Language：English   Publishing type：Research paper (scientific journal)  

Introduction: The association between complementary and alternative medicine (CAM) use and other health-related behaviors is an important issue. A previous study reported that complementary medicine use is related to greater use of cancer screening, whereas alternative medicine use is related to lower use of cancer screening. Given the sparse evidence from Japan, we aimed to examine the association of CAM use with cancer screening and medical checkups. We used a repeated cross-sectional survey of a nationally representative sample of Japanese people and conducted age-period-cohort analysis. Methods: The study population was 68,217 of 83,827 individuals observed from 2001 to 2013 who received cancer screening. CAM users were defined as individuals who received acupuncture, moxibustion, anma/massage/shiatsu, or judo therapy for their most worrisome symptom. The outcomes of interest were receiving stomach, lung, colorectal, uterine, and breast cancer screenings and medical checkups. Using crossclassified multilevel logistic regression models, we estimated odds ratios (ORs) and 95% credible intervals (CIs) for cancer screening and medical checkups. Results: For CAM users of complementary medicine, the adjusted ORs for stomach, lung, and colorectal cancer screening were 1.40 (95% CI: 1.35-1.44), 1.37 (95% CI: 1.34-1.40), and 1.52 (95% CI: 1.49-1.54), respectively. We found similar results for uterine and breast cancer screening, and medical checkups. Conclusions: Irrespective of whether they use CAM, CAM users in Japan tend to receive a variety of cancer screenings and medical checkups.

DOI： 10.1089/jicm.2023.0077

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/iae.0000000000003725

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Language：English   Publishing type：Research paper (scientific journal)  

Background Despite the impact of heat exposure caused by global warming, few studies have investigated the hourly effects of heat exposure and the risk of cardiovascular disease (CVD) in the elderly. We examined the associations between short-term heat exposure and the risk of CVD in the elderly in Japan and evaluated possible effect-measure modifications by rainy seasons that occur in East Asia. Methods and Results We conducted a time-stratified case-crossover study. The study included 6527 residents in Okayama City, Japan, aged ≥65 years who were transported to emergency hospitals between 2012 and 2019 for the onset of CVD during and a few months after the rainy seasons. We examined the linear associations between temperature and CVD-related emergency calls for each year and for hourly preceding intervals before the emergency call during the most relevant months. Heat exposure during 1 month after the end of the rainy season was associated with CVD risk; the odds ratio (OR) for a 1° C increase in temperature was 1.34 (95% CI, 1.29-1.40). When we further explored the nonlinear association by using the natural cubic spline model, we found a J-shaped relationship. Exposures 0 to 6 hours before the case event (preceding intervals 0-6 hours) were associated with CVD risk, particularly for the preceding interval 0 to 1 hour (OR, 1.33 [95% CI, 1.28-1.39]). For longer periods, the highest risk was at preceding intervals 0 to 23 hours (OR, 1.40 [95% CI, 1.34-1.46]). Conclusions Elderly individuals may be more susceptible to CVD after heat exposure during the month after the rainy season. As shown by finer temporal resolution analyses, short-term exposure to increasing temperature can trigger CVD onset.

DOI： 10.1161/JAHA.122.027046

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Language：English   Publishing type：Research paper (conference, symposium, etc.)   Publisher：(一社)日本循環器学会  

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Language：English   Publishing type：Research paper (conference, symposium, etc.)   Publisher：(一社)日本循環器学会  

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Despite an increasing number of students studying abroad worldwide, evidence about health risks while they are abroad is limited. Diarrhea is considered the most common travelers’ illness, which would also apply to students studying abroad. We examined diarrhea and related personal characteristics among Japanese students studying abroad. Japanese university students who participated in short-term study abroad programs between summer 2016 and spring 2018 were targeted (n = 825, 6–38 travel days). Based on a 2-week-risk of diarrhea (passing three or more loose or liquid stools per day) among travelers by country, the destination was separated into intermediate- and low-risk countries. After this stratification, the associations between personal characteristics and diarrhea during the first two weeks of their stay were evaluated using logistic regression models. Among participants in intermediate-risk countries, teenagers, males and those with overseas travel experience were associated with an elevated risk of diarrhea; the odds ratios (95% confidence intervals) were 2.42 (1.08–5.43) for teenagers (vs. twenties), 1.93 (1.08–3.45) for males (vs. females) and 2.37 (1.29–4.33) for those with overseas experience (vs. none). Even restricting an outcome to diarrhea during the first week did not change the results substantially. The same tendency was not observed for those in the low-risk countries. Teenage students, males and those with overseas travel experience should be cautious about diarrhea while studying abroad, specifically in intermediate-risk countries.

DOI： 10.1371/journal.pone.0279426

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

The attributable fraction (population) has attracted much attention from a theoretical perspective and has been used extensively to assess the impact of potential health interventions. However, despite its extensive use, there is much confusion about its concept and calculation methods. In this article, we discuss the concepts of and calculation methods for the attributable fraction and related measures in the counterfactual framework, both with and without stratification by covariates. Generally, the attributable fraction is useful when the exposure of interest has a causal effect on the outcome. However, it is important to understand that this statement applies to the exposed group. Although the target population of the attributable fraction (population) is the total population, the causal effect should be present not in the total population but in the exposed group. As related measures, we discuss the preventable fraction and prevented fraction, which are generally useful when the exposure of interest has a preventive effect on the outcome, and we further propose a new measure called the attributed fraction. We also discuss the causal and preventive excess fractions, and provide notes on vaccine efficacy. Finally, we discuss the relations between the aforementioned six measures and six possible patterns using a conceptual schema.

DOI： 10.1515/jci-2021-0068

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Mary Ann Liebert Inc  

DOI： 10.1089/jicm.2022.0631

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Other Link： https://www.liebertpub.com/doi/pdf/10.1089/jicm.2022.0631

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

AIM: A number of studies have indicated the potential benefits that breastfeeding has on reducing childhood obesity, but few studies have evaluated the effect on adolescent obesity. We examined the association between breastfeeding and overweight or obesity at 15 years of age using data from a large nationwide longitudinal study launched by the Japanese Government in 2001. METHODS: We analysed data for 26 164 participants with known infant feeding practices at 6 months of age, namely the duration of breastfeeding or formula feeding. Overweight or obesity at 15 years of age were calculated based on the subject's self-reported height and weight. Multinomial logistic regression analysis adjusted the data for child factors, namely sex, siblings, birth weight and physical activity clubs and the maternal factors of age, educational attainment and smoking status. RESULTS: Formula feeding was associated with an increased risk of overweight or obesity at 15 years of age. The adjusted odds ratios (95% confidence intervals) were 0.99 (0.89-1.09) for partial breastfeeding and 1.23 (1.02-1.48) for formula feeding, when exclusive breastfeeding was the reference category. CONCLUSION: Breastfeeding during infancy had potential benefits for overweight or obesity among 15-year-old adolescents. Our results provide further evidence of the importance of breastfeeding.

DOI： 10.1111/apa.16551

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000001558

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jclinepi.2022.02.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

We analyzed the local control (LC) of cervical squamous cell carcinoma treated by computed tomography (CT)-based image-guided brachytherapy (IGBT) using central shielding (CS). We also examined the value of tumor diameter before brachytherapy (BT) as a factor of LC. In total, 97 patients were analyzed between April 2016 and March 2020. Whole-pelvic (WP) radiotherapy (RT) with CS was performed, and the total pelvic sidewall dose was 50 or 50.4 Gy; IGBT was delivered in 3–4 fractions. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions, and distribution was modified manually by graphical optimization. The median follow-up period was 31.8 months (6.3–63.2 months). The 1- and 2-year LC rates were 89% and 87%, respectively. The hazard ratio was 10.11 (95% confidence interval: 1.48–68.99) for local recurrence in those with a horizontal tumor diameter ≥ 4 cm compared to those with < 4 cm before BT. In CT-based IGBT for squamous cell carcinoma, favorable LC can be obtained in patients with a tumor diameter < 4 cm before BT. However, if the tumor diameter is ≥ 4 cm, different treatment strategies such as employing interstitial-BT for dose escalation may be necessary.

DOI： 10.1093/jrr/rrac040

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/joim.13526

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

DOI： 10.1093/ije/dyac090

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Neurosurgery Publishing Group (JNSPG)  

OBJECTIVE

There have been no accurate surveillance data regarding the incidence rate of spinal arteriovenous shunts (SAVSs). Here, the authors investigate the epidemiology and clinical characteristics of SAVSs.

METHODS

The authors conducted multicenter hospital-based surveillance as an inventory survey at 8 core hospitals in Okayama Prefecture between April 1, 2009, and March 31, 2019. Consecutive patients who lived in Okayama and were diagnosed with SAVSs on angiographic studies were enrolled. The clinical characteristics and the incidence rates of each form of SAVS and the differences between SAVSs at different spinal levels were analyzed.

RESULTS

The authors identified a total of 45 patients with SAVSs, including 2 cases of spinal arteriovenous malformation, 5 cases of perimedullary arteriovenous fistula (AVF), 31 cases of spinal dural AVF (SDAVF), and 7 cases of spinal epidural AVF (SEAVF). The crude incidence rate was 0.234 per 100,000 person-years for all SAVSs including those at the craniocervical junction (CCJ) level. The incidence rate of SDAVF and SEAVF combined increased with advancing age in men only. In a comparative analysis between upper and lower spinal SDAVF/SEAVF, hemorrhage occurred in 7/14 cases (50%) at the CCJ/cervical level and in 0/24 cases (0%) at the thoracolumbar level (p = 0.0003). Venous congestion appeared in 1/14 cases (7%) at the CCJ/cervical level and in 23/24 cases (96%) at the thoracolumbar level (p < 0.0001).

CONCLUSIONS

The authors reported detailed incidence rates of SAVSs in Japan. There were some differences in clinical characteristics of SAVSs in the upper spinal levels and those in the lower spinal levels.

DOI： 10.3171/2021.7.spine21233

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Other Link： https://thejns.org/downloadpdf/journals/j-neurosurg-spine/36/4/article-p670.xml

Language：Japanese   Publishing type：Research paper (other academic)   Publisher：(公財)日本眼科学会  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

For decades, the sufficient cause model and the counterfactual model have shaped our understanding of causation in biomedical science, and the link between these two models has enabled us to obtain a deeper understanding of causality. Recently, a new causal model-the marginal sufficient component cause model-was proposed and applied in the context of interaction or mediation. The proponents of this model have emphasized its utility in visualizing the presence of "agonism" (a subtype of mechanistic interaction) in the counterfactual framework, claiming that the concept of agonism has not been clearly defined in causal inference and that agonistic interaction cannot be visualized by the conventional sufficient cause model. In this article, we illustrate that careful scrutiny based on the conventional sufficient cause model yields further insights into the concept of agonism in a more biologic sense. We primarily focus on the following three points: (1) "agonism" defined in the counterfactual model can be visualized as sets of sufficient causes in the conventional sufficient cause model; (2) although the so-called independent competing assumption or no redundancy assumption may seem irrelevant in the marginal sufficient component cause model, researchers do need to assume that potential completion times of relevant marginal sufficient causes differ; and (3) possibly differing potential completion times of marginal sufficient causes cannot be discerned until their hidden mechanistic paths are considered in the conventional sufficient cause model. In this rapidly progressing field of research, decades after its introduction, the sufficient cause model retains its worth.

DOI： 10.1097/EDE.0000000000001411

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Language：Japanese   Publisher：(NPO)日本脳神経血管内治療学会  

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Purpose Despite the increasing demand for public health measures to prevent problem gambling, few studies have examined the association between community characteristics and problem gambling. The aim of this nationally representative cross-sectional study was to investigate the relationship between a sense of community belonging and problem gambling in Canada. We also examined whether this relationship was modified by sex and marital status. Methods Canadian Community Health Survey (2013-2014) data from 38,968 residents of Quebec, Saskatchewan, Manitoba, and British Columbia were analyzed. Problem gambling was assessed using the Canadian Problem Gambling Index. We estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for problem gambling. Results The prevalence of problem gambling was 1.4% (1.9% among males; 0.9% among females). We observed an inverse dose-response relationship between a sense of community belonging and problem gambling. Compared with those with a very strong sense of community belonging, the adjusted ORs for problem gambling were 1.07 (95% CI 0.65-1.76) for a somewhat strong sense, 1.27 (95% CI 0.77-2.11) for a somewhat weak sense, and 2.32 (95% CI 1.34-4.02) for a very weak sense of community belonging. The association was more prominent among females (except for those widowed/divorced/separated), whereas no clear association was found among males, irrespective of marital status. Conclusion When implementing public health measures to reduce problem gambling, it would be useful to account for possible differential impacts of a sense of community belonging by sex and marital status, which may reflect significant social contexts among residents.

DOI： 10.1007/s00127-021-02040-w

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10654-021-00798-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Daedalus Enterprises  

BACKGROUND: Body mass index (BMI) can be an important indicator for health outcomes among critically ill patients. However, the association between BMI and ventilator dependence at ICU discharge among these patients remains unknown. We aimed to evaluate the association between BMI at ICU admission and ventilator dependence at the time of ICU discharge. As secondary outcomes, we used ICU mortality, hospital mortality, and implementation of tracheostomy during ICU stay. METHODS: This is a retrospective cohort study. The data were derived from The Japanese Intensive Care Patient Database, a nationwide ICU database in Japan. We included all patients in the registry who were >= 16 y old, received mechanical ventilation, and were admitted to an ICU between April 2018 and March 2019. On the basis of their BMI at ICU admission, subjects were classified as underweight (< 18.5 kg/m(2)); normal weight (6 18.5 kg/m(2) to < 23 kg/m(2)); overweight (6 23 kg/m(2) to < 27.5 kg/m(2)); or obese (6 27.5 kg/m(2)). RESULTS: Among 11,801 analyzed subjects, 388 (3.3%) subjects were ventilator-dependent at ICU discharge. Compared with normal-weight subjects, the risk for ventilator dependence at ICU discharge increased among underweight subjects even after adjusting for potential confounders and inter-ICU variance in 2-level multivariable logistic regression analysis (odds ratio 1.46 [95% CI 1.18-1.79]). Although obesity was also associated with a higher risk of ventilator dependence, the association was less clear (odds ratio 1.10 [95% CI 0.99-1.22]). The risk of ICU mortality, hospital mortality, and implementation of tracheostomy also increased in underweight subjects. CONCLUSIONS: Critically ill underweight subjects had a higher risk of ventilator dependence at ICU discharge compared to normal-weight subjects, even after adjusting for potential confounders and inter-ICU variance. The association between BMI and ventilator dependence should be examined using information on subjects' nutritional status and frailty in further studies

DOI： 10.4187/respcare.08660

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

BACKGROUND: Pulmonary metastasectomy could be considered one of the treatment options for disease control in sarcoma patients with pulmonary metastases; however, there is little consensus regarding the suitable criteria for predicting the likely outcomes in these patients. The aim of this study was to establish a prognostic benefit scoring system based on preoperatively examined prognostic factors for sarcoma patients with pulmonary metastases. METHODS: This was a single-center, retrospective cohort study conducted in a cohort of 135 sarcoma patients who underwent a first pulmonary metastasectomy at Okayama University Hospital between January 2006 and December 2015. Based on the results of a multivariable logistic regression analysis performed to determine the factors influencing 3-year mortality, a Sarcoma Lung Metastasis Score was created and its correlation with 3-year survival was analyzed. RESULTS: The results of the multivariate analysis revealed significant differences in the disease-free interval (< 2 years vs. ≥ 2 years; odds ratio (OR) 4.22, 95% confidence interval (CI) 1.67-10.70), maximum tumor diameter (≥ 15 mm vs. < 15 mm; OR 3.86, 95% CI 1.75-8.52), and number of pulmonary metastases (≥ 6 vs. < 6; OR 2.65, 95% CI 1.06-6.620). The Sarcoma Lung Metastasis Score, which was defined as the total score of these three factors, reliably predicted 3-year survival (score: 0, 89.5%; 1, 63.2%; 2, 39.0%; 3, 10.5%). CONCLUSIONS: Our newly proposed simple Sarcoma Lung Metastasis Score appears to be a useful prognostic predictor for sarcoma patients with pulmonary metastases, in that it could be helpful for the selection of appropriate treatments for these patients.

DOI： 10.1245/s10434-020-09272-1

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Other Link： http://link.springer.com/article/10.1245/s10434-020-09272-1/fulltext.html

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000001360

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Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Okayama Medical Association  

DOI： 10.4044/joma.133.55

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

BACKGROUND AND PURPOSE: To date, the incidence of intracranial and spinal arteriovenous shunts has not been thoroughly investigated. We aimed to clarify recent trends in the rates of intracranial and spinal arteriovenous shunts in Japan. METHODS: We conducted multicenter hospital-based surveillance at 8 core hospitals in Okayama Prefecture between April 1, 2009 and March 31, 2019. Patients who lived in Okayama and were diagnosed with cerebral arteriovenous malformations, dural arteriovenous fistulas (DAVFs), or spinal arteriovenous shunts (SAVSs) were enrolled. The incidence and temporal trends of each disease were calculated. RESULTS: Among a total of 393 cranial and spinal arteriovenous shunts, 201 (51.1%) cases of DAVF, 155 (39.4%) cases of cerebral arteriovenous malformation, and 34 (8.7%) cases of SAVS were identified. The crude incidence rates between 2009 and 2019 were 2.040 per 100 000 person-years for all arteriovenous shunts, 0.805 for cerebral arteriovenous malformation, 1.044 for DAVF, and 0.177 for SAVS. The incidence of all types tended to increase over the decade, with a notable increase in incidence starting in 2012. Even after adjusting for population aging, the incidence of nonaggressive DAVF increased 6.0-fold while that of SAVS increased 4.4-fold from 2010 to 2018. CONCLUSIONS: In contrast to previous studies, we found that the incidence of DAVF is higher than that of cerebral arteriovenous malformation. Even after adjusting for population aging, all of the disease types tended to increase in incidence over the last decade, with an especially prominent increase in SAVSs and nonaggressive DAVFs. Various factors including population aging may affect an increase in DAVF and SAVS.

DOI： 10.1161/STROKEAHA.120.032052

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

DOI： 10.1097/EDE.0000000000001306

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Language：English   Publishing type：Research paper (conference, symposium, etc.)   Publisher：(一社)日本循環器学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Baycinar Medical Publishing  

Objectives: This study aims to determine if obesity is a risk factor for a poor response to anti-tumor necrosis factor alpha (anti-TNF alpha) therapy in Japanese patients with rheumatoid arthritis (RA) using the appropriate body mass index (BMI) cut-off points for Asian populations.Patients and methods: This retrospective cohort study evaluated 382 outpatients with RA (98 males, 284 females; mean age 54.2 years; range, 18 to 84 years) who had received anti-TNFa therapy between May 2009 and July 2017. Patients were classified according to BMI at baseline as follows: <18.5 kg/m(2) (underweight), 18.5-23.0 kg/m(2) (normal weight), 23.0-27.5 kg/m(2) (overweight), and >= 27.5 kg/m(2) (obese). The response variable was defined as Simplified Disease Activity Index (SDAI) remission after 12 months. We estimated odds ratios (ORs) and their 95% confidence intervals (CIs) for poor response to the therapy.Results: After 87 patients were excluded, 183 (62.0%) of 295 had reached remission at the 12-month follow-up. Compared with normal-weight patients, the multivariate OR for poor response of obese patients was 2.2 (95% CI: 0.5-9.4). Adjusting for the baseline SDAI score, the corresponding OR was 1.8 (0.4-7.6).Conclusion: We found no statistically significant association between obesity and poor response to anti-TNFa therapy in Japanese patients with RA. Because this may partly be due to the limited statistical power of our study, further research is warranted to examine the possible effect modification across countries.

DOI： 10.46497/archrheumatol.2020.7852

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Language：Japanese   Publisher：(NPO)日本脳神経血管内治療学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Background: The non-technical skills for surgeons (NOTSS) system was developed as a tool to assess surgical skills for patient safety during surgery. This study aimed to develop a NOTSS-based training system for surgical trainees to acquire non-technical skills using a chest surgery scenario in a wet lab.Materials and methods: Trainees were categorized into three subgroups according to the years of experience as follows: Level A: 6 years or more; Level B: 3-5 years; and Level C: 1-2 years. Three stages of surgical procedure were designed: 1. chest wall resection and right upper lobe lobectomy, 2. right middle lobe sleeve lobectomy, and 3. right lower lobe lobectomy. One instructor was assigned to each operation table, who evaluated each participant's NOTSS scores consisting of 16 elements.Results: When comparing average NOTSS score of all the three procedures, significant differences were observed between Level A, B, and C trainees. As an example of varying elements by procedure, Level A trainees demonstrated differences in Situation Awareness, and a significant difference was observed in Level C trainees regarding the elements of Decision Making. On the contrary, no significant difference was observed among Level B trainees. In the comparison between first-time and experienced participants, a significant improvement was observed in some elements in Level B and C trainees.Conclusion: This study highlights the usefulness and feasibility of the NOTSS scoring system for surgeons with different experiences and the effectiveness of providing feedback to trainees during intraoperative handoffs in a wet lab.

DOI： 10.1016/j.amsu.2020.07.062

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Epidemiological Association  

Epidemiologists are increasingly encountering complex longitudinal data, in which exposures and their confounders vary during follow-up. When a prior exposure affects the confounders of the subsequent exposures, estimating the effects of the time-varying exposures requires special statistical techniques, possibly with structural (ie, counterfactual) models for targeted effects, even if all confounders are accurately measured. Among the methods used to estimate such effects, which can be cast as a marginal structural model in a straightforward way, one popular approach is inverse probability weighting. Despite the seemingly intuitive theory and easy-to-implement software, misunderstandings (or "pitfalls") remain. For example, one may mistakenly equate marginal structural models with inverse probability weighting, failing to distinguish a marginal structural model encoding the causal parameters of interest from a nuisance model for exposure probability, and thereby failing to separate the problems of variable selection and model specification for these distinct models. Assuming the causal parameters of interest are identified given the study design and measurements, we provide a step-by-step illustration of generalized computation of standardization (called the g-formula) and inverse probability weighting, as well as the specification of marginal structural models, particularly for time-varying exposures. We use a novel hypothetical example, which allows us access to typically hidden potential outcomes. This illustration provides steppingstones (or "tips") to understand more concretely the estimation of the effects of complex time-varying exposures.

DOI： 10.2188/jea.je20200226

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER INC  

PURPOSE: To compare surgical outcomes between the inverted internal limiting membrane (ILM) flap technique and ILM peeling for macular hole retinal detachment (MHRD) in eyes with high myopia. DESIGN: Multicenter cohort study. PARTICIPANTS: We retrospectively reviewed medical records of consecutive patients treated between June 2008 and September 2018 at 7 hospitals and included 100 eyes with MHRD associated with high myopia in our study. All eyes underwent vitrectomy with the inverted ILM flap technique (57 eyes) or ILM peeling (43 eyes) and were followed up for more than 6 months. METHODS: We estimated odds ratios and their 95% confidence intervals (CIs) for macular hole (MH) closure using multivariate logistic regression analysis. We also examined factors associated with the postoperative best-corrected visual acuity (BCVA) at the final visit using multiple linear regression analysis. MAIN OUTCOME MEASURES: Macular hole closure and postoperative BCVA at the final visit. RESULTS: The MH closure rate was significantly higher in the inverted ILM flap group (80.7%) than in the ILM peeling group (37.2%; P < 0.001). Moreover, postoperative BCVA at the final visit was significantly better in the former group (0.88 ± 0.48 vs. 0.99 ± 0.48; P = 0.03). The retinal attachment rate (ILM flap, 91.2%; ILM peeling, 79.5%; P = 0.229) and recovery rates for the external limiting membrane and ellipsoid zone line (ILM flap, 10.9%; ILM peeling, 0%; P = 0.12) showed no significant intergroup differences. After adjustment for age, axis, tamponade substance, and dye for ILM staining, the inverted ILM flap technique was associated strongly and positively with MH closure (odds ratio, 7.14; 95% CI, 2.72-18.7; P = 0.001). Moreover, the inverted ILM flap technique and preoperative BCVA were associated significantly and positively with the postoperative BCVA at the final visit. CONCLUSIONS: Our findings suggest that the MH closure rate and postoperative visual outcome for eyes with high myopia-associated MHRD are better with the inverted ILM flap technique than with ILM peeling. Thus, vitrectomy with the inverted ILM flap technique should be considered as the initial surgery for MHRD associated with high myopia.

DOI： 10.1016/j.oret.2020.03.021

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Epidemiological Association  

Graphical models are useful tools in causal inference, and causal directed acyclic graphs (DAGs) are used extensively to determine the variables for which it is sufficient to control for confounding to estimate causal effects. We discuss the following ten pitfalls and tips that are easily overlooked when using DAGs: 1) Each node on DAGs corresponds to a random variable and not its realized values; 2) The presence or absence of arrows in DAGs corresponds to the presence or absence of individual causal effect in the population; 3) "Non-manipulable" variables and their arrows should be drawn with care; 4) It is preferable to draw DAGs for the total population, rather than for the exposed or unexposed groups; 5) DAGs are primarily useful to examine the presence of confounding in distribution in the notion of confounding in expectation; 6) Although DAGs provide qualitative differences of causal structures, they cannot describe details of how to adjust for confounding; 7) DAGs can be used to illustrate the consequences of matching and the appropriate handling of matched variables in cohort and case-control studies; 8) When explicitly accounting for temporal order in DAGs, it is necessary to use separate nodes for each timing; 9) In certain cases, DAGs with signed edges can be used in drawing conclusions about the direction of bias; and 10) DAGs can be (and should be) used to describe not only confounding bias but also other forms of bias. We also discuss recent developments of graphical models and their future directions.

DOI： 10.2188/jea.je20190192

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Association for Cancer Research (AACR)  

A genetic variant on aldehyde dehydrogenase 2 (ALDH2 rs671, Glu504Lys) contributes to carcinogenesis after alcohol consumption. Somewhat conversely, the ALDH2 Lys allele also confers a protective effect against alcohol-induced carcinogenesis by decreasing alcohol consumption due to acetaldehyde-related adverse effects. Here, we applied a mediation analysis to five case-control studies for head and neck, esophageal, stomach, small intestine, and colorectal cancers, with 4,099 cases and 6,065 controls, and explored the potentially heterogeneous impact of alcohol drinking on digestive tract carcinogenesis by decomposing the total effect of the ALDH2 Lys allele on digestive tract cancer risk into the two opposing effects of the carcinogenic effect (direct effect) and the protective effect (indirect effect mediated by drinking behavior). Alcohol was associated with an increased risk of most digestive tract cancers, but significant direct effects were observed only for upper gastrointestinal tract cancer risk, and varied substantially by site, with ORs (95% confidence interval) of 1.83 (1.432.36) for head and neck cancer, 21.15 (9.11-49.12) for esophageal cancer, and 1.65 (1.38-1.96) for stomach cancer. In contrast, a significant protective indirect effect was observed on risk for all cancers, except small intestine cancer. These findings suggest that alcohol is a major risk factor for digestive tract cancers, but its impact as a surrogate for acetaldehyde exposure appears heterogeneous by site. Meanwhile, the behavior-related effect of the ALDH2 Lys allele results in a decreased risk of most digestive tract cancers.Significance: These findings support that genetic alcohol avoidance is a factor against alcohol-induced cancers.

DOI： 10.1158/0008-5472.can-19-2685

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Neuromuscular blocking agents play a significant role in improving the success rate for urgent intubation, although there is limited evidence about the effect on subsequent outcomes, such as the incidence of tracheostomy. In this retrospective cohort study, we aimed to examine the association between avoidance of neuromuscular blocking agents for urgent tracheal intubation and incidence of tracheostomy among patients in the intensive care unit (ICU). The setting of this study was an eight-bed ICU at a tertiary-care hospital in Okayama, Japan. We included patients who underwent urgent tracheal intubation at the emergency department or the ICU and were admitted to the ICU between April 2013 and November 2017. We extracted data on methods and medications of intubation, predictors for difficult intubation, Cormack-Lehane grade, patient demographics, primary diagnoses, reintubation. We estimated odds ratios and their 95% confidence intervals for elective tracheostomy during the ICU stay using logistic regression models. Of 411 patients, 46 patients underwent intubation without neuromuscular blocking agents and 61 patients underwent tracheostomy. After adjusting for potential confounders, patients who avoided neuromuscular blocking agents had more than double the odds of tracheostomy (odds ratio 2.59, 95% confidence interval 1.06-6.34, p value = 0.04). When stratifying the subjects by risk status for tracheostomy, the association was more pronounced in high-risk group, while we observed less significant association in the low-risk group. Avoidance of neuromuscular blocking agents for urgent intubation increases the risk of tracheostomy among emergency patients, especially those who have a higher risk for tracheostomy.

DOI： 10.1007/s11739-019-02214-0

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Other Link： http://link.springer.com/article/10.1007/s11739-019-02214-0/fulltext.html

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

The relationship between collapsibility and confounding has been subject to an extensive and ongoing discussion in the methodological literature. We discuss two subtly different definitions of collapsibility, and show that by considering causal effect measures based on counterfactual variables (rather than measures of association based on observed variables) it is possible to separate out the component of non-collapsibility which is due to the mathematical properties of the effect measure, from the components that are due to structural bias such as confounding. We provide new weights such that the causal risk ratio is collapsible over arbitrary baseline covariates. In the absence of confounding, these weights may be used for standardization of the risk ratio.

DOI： 10.1186/s12982-018-0083-9

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

The participants in randomized trials and other studies used for causal inference are often not representative of the populations seen by clinical decision-makers. To account for differences between populations, researchers may consider standardizing results to a target population. We discuss several different types of homogeneity conditions that are relevant for standardization: Homogeneity of effect measures, homogeneity of counterfactual outcome state transition parameters, and homogeneity of counterfactual distributions. Each of these conditions can be used to show that a particular standardization procedure will result in an unbiased estimate of the effect in the target population, given assumptions about the relevant scientific context. We compare and contrast the homogeneity conditions, in particular their implications for selection of covariates for standardization and their implications for how to compute the standardized causal effect in the target population. While some of the recently developed counterfactual approaches to generalizability rely upon homogeneity conditions that avoid many of the problems associated with traditional approaches, they often require adjustment for a large (and possibly unfeasible) set of covariates.

DOI： 10.1007/s10654-019-00571-w

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Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

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Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

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Language：Japanese   Publisher：(NPO)日本脳神経血管内治療学会  

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000000898

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.socscimed.2018.04.023

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier USA  

Background: Despite growth in the number of cruises worldwide, evidence about diarrhea experienced by cruise ship passengers remains sparse. We investigated rates of diarrhea and related factors among passengers on world cruises departing from Japan. Methods: Targeting passengers on five world cruises (n = 4180) from 2012 to 2013 (85–103 travel days), we calculated rates of health seeking behavior for diarrhea by sex, age group, and number of roommates for each cruise. We estimated rate ratios and 95% confidence intervals, using the group aged 20–39 years, women, and 2–4 roommates as referent categories. Results: We found 5.04–6.00 cases per 10,000 person-days in the five cruises, with an elevated number after calling at ports. Older passengers (&gt
60 years) and passengers with fewer roommates had an elevated risk of health seeking behavior for diarrhea, although passengers aged &lt
20 years had an elevated risk on one cruise. After controlling for covariates (including cruise), significant associations remained for passengers aged &gt
60 years and without roommates. Conclusions: Older passengers and passengers with fewer roommates may be more likely to seek medical treatment for diarrhea during travel on a world cruise, and should take preventive measures.

DOI： 10.1016/j.tmaid.2018.01.004

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Purpose: To show conditions of covariate balance for no confounding in the sufficient-cause model and discuss its relationship with exchangeability conditions.Methods: We consider the link between the sufficient-cause model and the counterfactual model, emphasizing that the target population plays a key role when discussing these conditions. Furthermore, we incorporate sufficient causes within the directed acyclic graph framework. We propose to use each of the background factors in sufficient causes as representing a set of covariates of interest and discuss the presence of covariate balance by comparing joint distributions of the relevant background factors between the exposed and the unexposed groups.Results: We show conditions for partial covariate balance, covariate balance, and full covariate balance, each of which is stronger than partial exchangeability, exchangeability, and full exchangeability, respectively. This is consistent with the fact that the sufficient-cause model is a "finer" model than the counterfactual model.Conclusions: Covariate balance is a sufficient, but not a necessary, condition for no confounding irrespective of the target population. Although our conceptualization of covariate imbalance is closely related to the recently proposed counterfactual-based definition of a confounder, the concepts of covariate balance and confounder should be clearly distinguished. (C) 2017 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.annepidem.2017.11.005

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Background: Factors influencing the susceptibility of the elderly to the adverse health effects of short-term exposure to desert dust have yet to be explored. We aimed to identify the disease histories that increase the susceptibility of the elderly to disease onset induced by dust events.Methods: We used a time-stratified case-crossover design using data on 17,874 elderly residents (>= 65 years) of Okayama, Japan, who were transported to hospital emergency rooms because of cardiovascular and respiratory diseases between 2006 and 2010. We used conditional logistic models to calculate the odds ratios (ORs) per inter-quartile increase of Asian dust. We then conducted stratified analyses based on patients with or without a history of chronic disease.Results: Dust concentration was associated with a higher risk of cardiovascular (3-day lag), cerebrovascular (same day), and respiratory (3-day lag) disease onset. Patients with a history of respiratory disease had a higher risk of cardiovascular (OR: 1.09 [95% confidence interval (CI) = 1.00, 1.19] vs. 0.99 [0.97, 1.01]; P for interaction = 0.03) or cerebrovascular (1.15 [1.01, 1.31] vs. 0.99 [0.97, 1.01]; P = 0.02) disease onset (2-day lag) than those without. Patients with diabetes also had a higher risk of cerebrovascular disease onset (1.09 [1.00, 1.19] vs. 0.99 [0.97, 1.01]; P = 0.05) (2-day lag). In contrast, patients with a history of cerebrovascular disease had a lower risk of respiratory disease.Conclusions: People with a history of respiratory disease or diabetes might have a greater susceptibility to cardiovascular disease from Asian dust and would therefore benefit from proactive interventions during desert dust events.

DOI： 10.1097/ede.0000000000000700

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Background: Most studies that examined risk factors for wound complications after head and neck reconstruction analyzed various complications collectively. Moreover, they included a wide variety of resection areas and reconstruction materials. To overcome these limitations, both the resection area and reconstruction method were constrained in the present study.Methods: Patients who underwent free jejunal graft reconstruction after pharyngolaryngoesophagectomy for hypopharyngeal cancer were enrolled. The outcomes of interest were abscesses, fistulas, and cervical skin flap necrosis.Results: Abscesses, fistulas, and cervical skin flap necrosis developed in 19.3%, 11.3%, and 8.2% of 773 patients, respectively. A significant relationship was found between use of an open drain and abscess formation and between a longer operation time and cervical skin flap necrosis.Conclusion: Our findings suggest that use of an open drain, cardiovascular disease, and a longer operation time are significant risk factors for abscess formation, fistula formation, and cervical skin flap necrosis, respectively.

DOI： 10.1002/hed.24874

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

AimDespite increased interest in an obesity paradox (i.e. a survival advantage of being obese), evidence remains sparse in Japanese populations. We aimed to verify this phenomenon among community-dwelling older adults in Japan.MethodsOlder adults aged 65-84 years randomly chosen from all 74 municipalities in Shizuoka Prefecture completed questionnaires including body mass index information. Participants were followed from 1999 to 2009. Following World Health Organization guidelines, participants were classified using an appropriate body mass index for Asian populations as follows: <18.5 kg/m(2) (underweight), 18.5-23.0 kg/m(2) (normal weight), 23.0-27.5 kg/m(2) (overweight) and 27.5 kg/m(2) (obesity). We estimated hazard ratios and their 95% confidence intervals for all-cause mortality, controlling for sex, age, smoking status, alcohol consumption, physical activity, hypertension and diabetes mellitus.ResultsCompared with normal-weight participants, overweight/obese participants tended to have lower hazard ratios; the multivariate hazard ratios (95% confidence interval) were 0.86 (0.62-1.19) for obesity, 0.83 (0.73-0.94) for overweight and 1.60 (1.40-1.82) for underweight. In subgroup analyses by sex and age, the hazard ratios tended to be lower among obese men, albeit not significantly; hazard ratios (95% confidence interval) were 0.56 (0.25-1.27) in men aged 65-74 years, and 0.78 (0.41-1.45) in men aged 75-84 years.ConclusionsThe present study provides evidence of a conservative obesity paradox among older Japanese people, using the appropriate body mass index cut-off points for Asian populations. In particular, obese older men tend to have a lower risk of all-cause mortality. Geriatr Gerontol Int 2017; 17: 1257-1264.

DOI： 10.1111/ggi.12851

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Epidemiological Association  

Confounding is a major concern in epidemiology. Despite its significance, the different notions of confounding have not been fully appreciated in the literature, leading to confusion of causal concepts in epidemiology. In this article, we aim to highlight the importance of differentiating between the subtly different notions of confounding from the perspective of counterfactual reasoning. By using a simple example, we illustrate the significance of considering the distribution of response types to distinguish causation from association, highlighting that confounding depends not only on the population chosen as the target of inference, but also on the notions of confounding in distribution and confounding in measure. This point has been relatively underappreciated, partly because some literature on the concept of confounding has only used the exposed and unexposed groups as the target populations, while it would be helpful to use the total population as the target population. Moreover, to clarify a further distinction between confounding "in expectation" and "realized" confounding, we illustrate the usefulness of examining the distribution of exposure status in the target population. To grasp the explicit distinction between confounding in expectation and realized confounding, we need to understand the mechanism that generates exposure events, not the product of that mechanism. Finally, we graphically illustrate this point, highlighting the usefulness of directed acyclic graphs in examining the presence of confounding in distribution, in the notion of confounding in expectation. (C) 2016 The Authors. Publishing services by Elsevier B.V. on behalf of The Japan Epidemiological Association.

DOI： 10.1016/j.je.2016.09.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Objective: Social capital, the collective resources of groups including perceptions of trust and reciprocity, is recognized as an important contributor to suicide. We examined the association of individual-and community-level social capital with suicidal ideation after adjusting for social support among older adults living in the community. Methods: In August 2010 we sent questionnaires to all residents aged 65 years and older living in 3 rural municipalities (N = 21,232) in Okayama Prefecture, Japan; 13,919 questionnaires were returned (response rate: 65.6%). The final analysis included 10,094 participants. The outcome variable was suicidal ideation. Exposure variables were individual-level mistrust and lack of reciprocity (level 1), and the aggregated responses of these variables from 35 communities in the municipalities (level 2). Covariates included age, sex, educational attainment, marital status, the number of cohabitants, years of residence, self-rated socioeconomic status, disability, social support, and psychological distress. Multilevel logistic regression analysis was performed to obtain odds ratios (ORs) and 95% confidence intervals (CIs). Results: After adjusting for social support and psychological distress, we found that mistrust and lack of reciprocity were only associated with suicidal ideation at the individual level. Stratified analysis showed that among subjects with psychological distress, mistrust was associated with suicidal ideation at individual (OR: 1.88; 95% CI: 1.42-2.51) and community levels (OR: 1.98; 95% CI: 1.02-3.81). Conclusions: Our findings show that individual-and community-level social capital is a possible protective factor for suicidal ideation, particularly for people with psychological distress.

DOI： 10.1016/j.jagp.2016.10.014

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Purpose: To provide an organizational schema for systematic error and random error in estimating causal measures, aimed at clarifying the concept of errors from the perspective of causal inference.Methods: We propose to divide systematic error into structural error and analytic error. With regard to random error, our schema shows its four major sources: nondeterministic counterfactuals, sampling variability, a mechanism that generates exposure events and measurement variability.Results: Structural error is defined from the perspective of counterfactual reasoning and divided into nonexchangeability bias (which comprises confounding bias and selection bias) and measurement bias. Directed acyclic graphs are useful to illustrate this kind of error. Nonexchangeability bias implies a lack of "exchangeability" between the selected exposed and unexposed groups. A lack of exchangeability is not a primary concern of measurement bias, justifying its separation from confounding bias and selection bias. Many forms of analytic errors result from the small-sample properties of the estimator used and vanish asymptotically. Analytic error also results from wrong (misspecified) statistical models and inappropriate statistical methods.Conclusions: Our organizational schema is helpful for understanding the relationship between systematic error and random error from a previously less investigated aspect, enabling us to better understand the relationship between accuracy, validity, and precision. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.annepidem.2016.09.008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Background. The risk factors for thrombus formation in anastomotic vessels in free-flap head and neck reconstruction have been previously reported. However, the evidence is inconsistent.Methods. In total, 773 patients who underwent free jejunal graft reconstruction after pharyngolaryngoesophagectomy for hypopharyngeal cancer were enrolled at 12 institutions in Japan from 1995 to 2006. Both the resection area and the applied reconstruction method were constrained to overcome the limitations of previous studies. After the exclusion of recurrent cases, odds ratios (ORs) and 95% confidence intervals (CIs) for thrombosis were calculated in a multivariate logistic regression analysis.Results. Postoperative anastomotic thrombosis developed in 23 patients (3.0%). In the multivariate analysis, the OR for thrombosis per 100-mL increase in blood loss was 1.24 (95% CI = 1.02-1.51), even after controlling for other risk factors.Conclusion. Our results show that the blood loss volume is an independent risk factor for thrombosis in free tissue grafts. (C) 2016 Wiley Periodicals, Inc.

DOI： 10.1002/hed.24504

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Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000000516

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Background: After the Great East Japan Earthquake and Tsunami in March 2011, radioactive elements were released from the Fukushima Daiichi Nuclear Power Plant. Based on prior knowledge, concern emerged about whether an increased incidence of thyroid cancer among exposed residents would occur as a result.Methods: After the release, Fukushima Prefecture performed ultrasound thyroid screening on all residents ages 18 years. The first round of screening included 298,577 examinees, and a second round began in April 2014. We analyzed the prefecture results from the first and second round up to December 31, 2014, in comparison with the Japanese annual incidence and the incidence within a reference area in Fukushima Prefecture.Results: The highest incidence rate ratio, using a latency period of 4 years, was observed in the central middle district of the prefecture compared with the Japanese annual incidence (incidence rate ratio = 50; 95% confidence interval [CI] = 25, 90). The prevalence of thyroid cancer was 605 per million examinees (95% CI = 302, 1,082) and the prevalence odds ratio compared with the reference district in Fukushima Prefecture was 2.6 (95% CI = 0.99, 7.0). In the second screening round, even under the assumption that the rest of examinees were disease free, an incidence rate ratio of 12 has already been observed (95% CI = 5.1, 23).Conclusions: An excess of thyroid cancer has been detected by ultrasound among children and adolescents in Fukushima Prefecture within 4 years of the release, and is unlikely to be explained by a screening surge.

DOI： 10.1097/ede.0000000000000385

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000000468

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

DOI： 10.1371/journal.pone.0144683

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

ObjectiveNovel countermeasures to increase healthcare expenditures should be explored in rapidly aging societies, including Japan. Social support is a resource for the older people that effectively reduces psychological distress, with or without specialized health service provision. This cross-sectional study was conducted to determine whether home visits by commissioned welfare volunteers (organizations of community residents assigned by national or local governments) are associated with a lower risk of psychological distress among the older people.MethodsQuestionnaires were sent in August 2010 to all residents aged 65years in three municipalities (n=21,232) in Okayama Prefecture in Japan; 13,929 were returned (response rate=65.6%). The final sample size for the analysis was 11,312 participants. Home visits, psychological distress (Kessler Psychological Distress Scale: K6>5), and severe psychological distress (K6>13) were measured by the questionnaire. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for psychological distress, adjusting for age, gender, education, marital status, and qualification for long-term care insurance.ResultsThe prevalence was 41.4% for psychological distress and 6.5% for severe psychological distress among all participants. Home visits were significantly associated with a lower risk of psychological distress after adjusting for the covariates (OR: 0.71, 95% CI: 0.65-0.77). These associations were comparable for men and women. The association was clearer for severe psychological distress (OR: 0.51, 95% CI: 0.43-0.61).ConclusionsHome visits by commissioned welfare volunteers are significantly associated with a lower risk of psychological distress among older people. Copyright (c) 2015 John Wiley & Sons, Ltd.

DOI： 10.1002/gps.4268

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Despite accumulating evidence, previous studies have not clearly separated the contribution of community-level social capital on mental health from that of individual-level social support. We examined the association between community-level social capital and psychological distress in a sample of older Japanese individuals, taking into account the effects of individual-level social capital and social support. We collected data via a cross-sectional survey among all residents aged &gt;= 65 in three rural municipalities in Okayama Prefecture. We measured two components of social capital in the questionnaire: perceptions of trust and reciprocity in the community. Community-level social capital was obtained by aggregating individual responses and calculating the proportion of subjects reporting mistrust and lack of reciprocity. Psychological distress was assessed by the Kessler Psychological Distress scale. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for psychological distress using two-level Poisson regression models (9,761 individuals nested within 35 communities). The prevalence of psychological distress was 39.8%. Low community-level social capital was associated with psychological distress, even after controlling for individual-level social support, age, sex, educational attainment, frequency of alcohol consumption, smoking status, body mass index, marital status, socioeconomic status, and number of cohabiters. The adjusted RRs per 10% increase of the proportion of mistrust and lack of reciprocity in the communities were 1.23 (95% CI: 1.01-1.51) and 1.12 (95% CI: 1.02-1.24), respectively. Lower levels of community-level social capital are associated with psychological distress among the Japanese elderly population, even after adjusting for individual- level perceptions of social capital and social support.

DOI： 10.1371/journal.pone.0142629

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0000000000000304

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BMJ  

Objectives: We investigated the associations between self-rated health and social capital among Croatian high school students.Design: A cross-sectional survey among high school students was carried out in the 2013-2014 school year.Setting: High schools in Croatia.Participants: Subjects were 3427 high school students (1688 males and 1739 females), aged 17-18 years.Main outcome measure: Self-rated health was assessed by the single item: "How do you perceive your health?". Possible responses were arranged along a five-item Likert-type scale: 1 very poor, 2 poor, 3 fair, 4 good, 5 excellent. The outcome was binarised as 'good health' (excellent, good or fair) versus 'poor health' (poor or very poor).Methods: We calculated ORs and 95% CIs for good self-rated health associated with family, neighbourhood and school social capital, while adjusting for gender, self-perceived socioeconomic status, psychological distress, physical activity and body mass index. We used generalised estimating equations using an exchangeable correlation matrix with robust SEs.Results: Good self-rated health was significantly associated with higher family social capital (OR 2.43; 95% CI 1.55 to 3.80), higher neighbourhood trust (OR 2.02; 95% CI 1.48 to 2.76) and higher norms of reciprocity at school (OR 1.79; 95% CI 1.13 to 2.84). When all of the social capital variables were entered simultaneously, good self-rated health remained significantly associated with higher family social capital (OR 1.98; 95% CI 1.19 to 3.30), neighbourhood trust (OR 1.77; 95% CI 1.25 to 2.51) and reciprocity at school (OR 1.71; 95% CI 1.08 to 2.73).Conclusions: Higher levels of social capital were independently associated with higher self-rated health among youth. Intervention and policies that leverage community social capital might serve as an avenue for health promotion in youth.

DOI： 10.1136/bmjopen-2014-007184

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Language：English   Publisher：Dr. Dietrich Steinkopff Verlag GmbH and Co. KG  

DOI： 10.1007/s00127-014-0967-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER IRELAND LTD  

Objective: Permanent hearing impairment has a life-long impact on children and its early identification is important for language development. A newborn hearing screening (NHS) program has started in Okayama Prefecture, Japan, in 1999 to detect hearing impairment immediately after birth. We aim to examine the effect of this screening program on vocabulary development in pre-school children in a before and after comparative study design.
Methods: A total of 107 5-year-old children who graduated from Okayama Kanariya Gakuen (an auditory center for hearing-impaired children) between 1998 and 2011 were enrolled in this study. The pre-NHS group (n = 40) was defined as those who graduated between 1998 and 2003, while the post-NHS group (n = 67) was defined as those who graduated between 2004 and 2011. The primary outcome was receptive vocabulary, which was assessed by the Picture Vocabulary Test [score &lt;18 (low) vs. score &gt;18 (high)]. The secondary outcome was productive vocabulary, or the number of productive words, which was assessed by an original checklist [&lt;1773 words (low) vs. &gt;1773 (high)]. We calculated odds ratios and 95% confidence intervals for vocabulary development and compared both groups.
Results: The adjusted Picture Vocabulary Test score and number of productive words were significantly higher (p &lt; 0.01) in the post-NHS group than the pre-NHS group. Odds ratios were 2.63 (95% confidence interval: 1.17-5.89) for receptive vocabulary and 4.17 (95% confidence interval: 1.69-10.29) for productive vocabulary.
Conclusions: The introduction of NHS in Okayama Prefecture significantly improved both receptive and productive vocabulary development in hearing-impaired children. (C) 2014 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.ijporl.2014.12.006

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

<title>Abstract</title>
Background: Geographical inequalities in suicide have risen dramatically across 47 prefectures in Japan since 1995. We sought to examine temporal changes in the associations between prefecture-level economic conditions and completed suicide during the recent 35 years, controlling for individual composition in each prefecture. Methods: Based on quinquennial vital statistics and census data from 1975 to 2010, we analysed the entire population aged 25–64 years. The total number of suicides was 87 553 men and 34 559 women. As indicators of prefecture-level economic conditions, we used average yearly income, average savings and income inequality (measured by Gini coefficients for yearly income). For each sex, we estimated odds ratios and 95% credible intervals for suicide using multilevel logistic regression models, with cells at level 1, years at level 2 and prefectures at level 3. Results: Even after adjusting for individual age, occupation and time trends, low average savings at prefecture level were associated with a higher risk of suicide among men (odds ratio in low vs. high savings: 1.13, 95% credible interval: 1.05–1.21), whereas no clear patterns were observed with other economic indicators. When we further examined the associations in year-specific models by conducting a two-level analysis, both average yearly income and average savings were inversely associated with suicide risk in recent years. No clear association was found between income inequality and suicide risk for either sex. Conclusion: The present findings suggest that low area socioeconomic status may be driving the growing geographical inequalities in suicide in Japan, primarily among men.

DOI： 10.1093/eurpub/cku023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

The main purpose of this study was to determine the relationships between Japanese individuals' interest in living wills and their preferred end-of-life care and death locations. Questionnaires were mailed to 1,000 individuals aged &gt;= 50 to measure these 2 factors. We examined the associations between the respondents' characteristics and their preferred care and death locations by using multinomial logistic regression models. The response rate was 74%. Home was the most frequently preferred place for end-of-life care (64%), and a palliative care unit (PCU) was the most commonly preferred place to die (51%). Living will interest was associated with a preference for care (odds ratio [OR] 4.74, 95% confidence interval [CI] 1.95-12.1) and death (OR 2.75, 95% CI 1.70-4.47) in a PCU rather than a hospital, but it was not associated with the choice between receiving care or dying at home instead of a hospital. We must consider why Japanese people think home death is impracticable. The Japanese palliative care system should be expanded to meet patients' end-of-life needs, and this includes not only facilitating home care but also increasing access to PCU care.

DOI： 10.18926/AMO/53023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Background: Epidemiological studies have shown adverse effects of short-term exposure to air pollution on respiratory disease outcomes; however, few studies examined this association on an hourly time scale. We evaluated the associations between hourly changes in air pollution and the risk of respiratory disease in the elderly, using the time of the emergency call as the disease onset for each case.Methods: We used a time-stratified case-crossover design. Study participants were 6,925 residents of the city of Okayama, Japan, aged 65 or above who were taken to hospital emergency rooms between January 2006 and December 2010 for onset of respiratory disease. We calculated city-representative hourly average concentrations of air pollutants from several monitoring stations. By using conditional logistic regression models, we estimated odds ratios per interquartile-range increase in each pollutant by exposure period prior to emergency call, adjusting for hourly ambient temperature, hourly relative humidity, and weekly numbers of reported influenza cases aged >= 60.Results: Suspended particulate matter (SPM) exposure 24 to <72 hours prior to the onset and ozone exposure 48 to <96 hours prior to the onset were associated with the increased risk of respiratory disease. For example, following one interquartile-range increase, odds ratios were 1.05 (95% confidence interval: 1.01, 1.09) for SPM exposure 24 to <48 hours prior to the onset and 1.13 (95% confidence interval: 1.04, 1.23) for ozone exposure 72 to <96 hours prior to the onset. Sulfur dioxide (SO2) exposure 0 to <24 hours prior to onset was associated with the increased risk of pneumonia and influenza: odds ratio was 1.07 per one interquartile-range increase (95% confidence interval: 1.00, 1.14). Elevated risk for pneumonia and influenza of SO2 was observed at shorter lags (i.e., 8-18 hours) than the elevated risks for respiratory disease of SPM or ozone. Overall, the effect estimates for chronic obstructive pulmonary disease and allied conditions were equivocal.Conclusions: This study provides further evidence that hourly changes in air pollution exposure increase the risks of respiratory disease, and that SO2 may be related with more immediate onset of the disease than other pollutants.

DOI： 10.1186/1476-069x-13-67

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Objective: To evaluate the direct health effects of Asian dust on ambulance calls and its role as an effect modifier on the effects of anthropogenic air pollution in Japan. Methods: The subjects were 51,945 elderly residents who visited hospital emergency departments from 2006 to 2010. We evaluated the impact of Asian dust by time-series analyses and the excess risk from suspended particulate matter (SPM) stratified by Asian-dust exposure. Results: Asian dust was associated with daily ambulance calls due to all-cause, cardiovascular, and respiratory disease independently of SPM, for example, the relative risk per interquartile increase in Asian dust (3-day lag) was 1.021 (1.002 to 1.039) for cardiovascular disease. Furthermore, Asian dust modified the effects of SPM on cardiovascular and respiratory diseases. Conclusions: Asian dust had adverse effects and modified the effect of SPM.

DOI： 10.1097/jom.0000000000000334

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Objectives: We evaluated the association between short-term exposure to outdoor air pollution and out-of-hospital cardiac arrest in Japan. Methods: We studied 558 residents of Okayama, Japan, who visited hospital emergency departments between January 2006 and December 2010 for out-of-hospital cardiac arrest using a time-stratified case-crossover design. We calculated city-representative average concentrations of different air pollutants and examined the association between air pollution and cardiac arrest. Results: Exposure to air pollution was associated with an elevated risk of cardiac arrest; for example, odds ratios was 1.17 (95% confidence interval, 1.02 to 1.33) per interquartile-range increase in suspended particulate matter concentrations in the previous 48 to 72 hours. We also observed different susceptibilities to suspended particulate matter and ozone exposures by age category. Conclusions: Short-term exposure to outdoor air pollution was associated with increased risk of cardiac arrest.

DOI： 10.1097/jom.0000000000000274

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.annepidem.2014.04.003

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DOI： 10.1097/ede.0000000000000114

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Background and Purpose Few studies have examined the effect of hourly changes in air pollution on cardiovascular disease morbidity. We evaluated the associations between hourly changes in air pollution and the risks of several types of cardiovascular disease.Methods We used a time-stratified case-crossover design. Study participants were 10 949 residents of the city of Okayama, Japan, aged 65 years who were taken to hospital emergency rooms between January 2006 and December 2010 for onset of cardiovascular disease. We calculated city representative hourly average concentrations of air pollutants from several monitoring stations and examined the associations between air pollution exposure before the case event, focusing mainly on suspended particulate matter, and disease onset.Results Suspended particulate matter exposure 0 to <6 hours before the case events was associated with risks of onset of cardiovascular and cerebrovascular disease; odds ratios after 1 interquartile range increase in suspended particulate matter exposure were 1.04 (95% confidence interval, 1.01-1.06) for cardiovascular disease and 1.04 (95% confidence interval, 1.00-1.08) for cerebrovascular disease. We observed an elevated risk of hemorrhagic as well as ischemic stroke, but the risk was slightly higher for hemorrhagic stroke, and this elevation was persistent. Women tended to have higher effect estimates.Conclusions This study provides further evidence that particulate matter exposure increases the risks of onset of cardiovascular and cerebrovascular disease (including hemorrhagic stroke) shortly after exposure.

DOI： 10.1161/strokeaha.114.005227

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Aims Social support has consistently been reported to be effective in reducing suicidal ideation. This cross-sectional study was performed to determine whether home visits by commissioned welfare volunteers (i.e., organizations of community residents appointed by national or prefectural governments) are associated with a lower risk of suicidal ideation among the elderly.Methods In August 2010, questionnaires were sent to all residents aged >= 65 years in three municipalities (n = 21,232) in Okayama prefecture, Japan, and 13,929 returned the questionnaire (response rate: 65.6 %). We finally analyzed 11,218 subjects. Both home visits by commissioned welfare volunteers and suicidal ideation within the last 30 days were assessed in the questionnaire. Odds ratios (ORs) and 95 % confidence intervals (CIs) for suicidal ideation were calculated adjusting for age, sex, educational attainment, and marital status. We then additionally adjusted for instrumental and emotional support, separately.Results The prevalence of suicidal ideation was 10.0 % and higher in women than in men (11.4 % vs. 8.0 %). Home visits were significantly associated with a lower risk of suicidal ideation after adjusting for instrumental and emotional support, respectively (OR: 0.60, 95 % CI: 0.53-0.69; OR: 0.67, 95 % CI: 0.59-0.78). In sex-stratified analysis, the association was clearer for women than for men: the corresponding ORs among women were 0.55 (95 % CI: 0.46-0.65) and 0.61 (95 % CI: 0.52-0.73), whereas they were 0.71 (95 % CI: 0.56-0.90) and 0.78 (95 % CI: 0.61-0.99) among men.Conclusion Our findings suggest that home visits by commissioned welfare volunteers are significantly associated with lower suicidal ideation among the elderly, particularly in women.

DOI： 10.1007/s00127-013-0752-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

The aim of this study was to examine trends in the geographic distribution of nursing staff in Japan from 2000 to 2010. We examined time trends in the rates of nursing staff per 100,000 population across 349 secondary health service areas. Using the Gini coefficient as a measure of inequality, we separately analyzed the data of 4 nursing staff types: public health nurses (PHN), midwives (MW), nurses (NS), and associate nurses (AN). Then, using multilevel Poisson regression models, we calculated the rate ratios (RRs) and their 95% confidence intervals (CIs) for each type of nursing staff per 1-year change. Overall, the distribution of PUN, MW, and NS improved slightly in terms of the Gini coefficient. After adjusting for prefectural capital and population density, PHN, MW, and NS significantly increased; the RRs per 1-year increment were 1.022 (95% CI: 1.020-1.023), 1.021 (95% CI: 1.019-1.022), and 1.037 (95% CI: 1.037-1.038), respectively. In contrast, AN significantly decreased; the RR per 1-year increment was 0.993 (95% CI: 0.993-0.994). Despite the considerable increase in the absolute number of nursing staff in Japan (excluding AN), this increase did not lead to a sufficient improvement in distribution over the last decade.

DOI： 10.18926/AMO/52406

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DOI： 10.1097/ede.0000000000000060

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DOI： 10.1097/ede.0000000000000062

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DOI： 10.1097/ede.0000000000000050

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Background: A growing number of studies have sought to examine the health associations of workplace social capital; however, evidence of associations with overweight is sparse. We examined the association between individual perceptions of workplace social capital and overweight among Japanese male and female employees.Methodology/Principal Findings: We conducted a cross-sectional survey among full-time employees at a company in Osaka prefecture in February 2012. We used an 8-item measure to assess overall and sub-dimensions of workplace social capital, divided into tertiles. Of 1050 employees, 849 responded, and 750 (624 men and 126 women) could be linked to annual health check-up data in the analysis. Binomial logistic regression models were used to calculate odds ratios and 95% confidence intervals for overweight (body mass index: >= 25 kg/m(2), calculated from measured weight and height) separately for men and women. The prevalence of overweight was 24.5% among men and 14.3% among women. Among men, low levels of bonding and linking social capital in the workplace were associated with a nearly 2-fold risk of overweight compared to high corresponding dimensions of social capital when adjusted for age, sleep hours, physiological distress, and lifestyle. In contrast, among women we found lower overall and linking social capital to be associated with lower odds for overweight even after covariate adjustment. Subsequently, we used multinomial logistic regression analyses to assess the relationships between a 1 standard deviation (SD) decrease in mean social capital and odds of underweight/overweight relative to normal weight. Among men, a 1-SD decrease in overall, bonding, and linking social capital was significantly associated with higher odds of overweight, but not with underweight. Among women, no significant associations were found for either overweight or underweight.Conclusions/Significance: We found opposite gender relationships between perceived low linking workplace social capital and overweight among Japanese employees.

DOI： 10.1371/journal.pone.0088084

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Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN PRIMARY CARE ASSOCIATION  

Introduction : We report the effect of adaptive servo ventilation (ASV) treatment on heart failure in a home care setting.<br>Methods : For eight home care patients aged ≥75 with heart failure, we diagnosed sleep-disordered breathing (SDB) by using a simplified monitor and implemented ASV treatment. We assessed its effect on heart failure by using NT-proBNP. We also assessed its effects on SDB by using apnea hypopnea index (AHI).<br>Results : Three patients dropped out because they felt fear of putting on the mask. Among the other five patients, we observed a significant decrease rate of NT-proBNP (mean : -0.43, 95% confidence interval (CI) : -0.64, -0.22) after the ASV treatment. With regard to AHI, we observed a decreasing tendency (mean : -20.4 /hour, 95% CI : -41.2/hour, 0.4/hour).<br>Conclusion : This study suggests that ASV treatment is effective for a treatment of heart failure in a home care setting.

DOI： 10.14442/generalist.37.342

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Background: The counterfactual approach provides a clear and coherent framework to think about a variety of important concepts related to causation. Meanwhile, directed acyclic graphs have been used as causal diagrams in epidemiologic research to visually summarize hypothetical relations among variables of interest, providing a clear understanding of underlying causal structures of bias and effect modification. In this study, the authors aim to further clarify the concepts of bias (confounding bias and selection bias) and effect modification in the counterfactual framework.Methods: The authors show how theoretical data frequencies can be described by using unobservable response types both in observational studies and in randomized controlled trials. By using the descriptions of data frequencies, the authors show epidemiologic measures in terms of response types, demonstrating significant distinctions between association measures and effect measures. These descriptions also demonstrate sufficient conditions to estimate effect measures in observational studies. To illustrate the ideas, the authors show how directed acyclic graphs can be extended by integrating response types and observed variables.Results: This study shows a hitherto unrecognized sufficient condition to estimate effect measures in observational studies by adjusting for confounding bias. The present findings would provide a further understanding of the assumption of conditional exchangeability, clarifying the link between the assumptions for making causal inferences in observational studies and the counterfactual approach. The extension of directed acyclic graphs using response types maintains the integrity of the original directed acyclic graphs, which allows one to understand the underlying causal structure discussed in this study.Conclusions: The present findings highlight that analytic adjustment for confounders in observational studies has consequences quite different from those of physical control in randomized controlled trials. In particular, the present findings would be of great use when demonstrating the inherent distinctions between observational studies and randomized controlled trials.

DOI： 10.1186/1471-2288-13-101

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Background: To date, only a small amount of research on bonding/bridging social capital has separately examined their effects on health though they have been thought to have differential effects on health outcomes. By using a large population-based sample of elderly Japanese people, we sought to investigate the association between bonding and bridging social capital and self-rated health for men and women separately.Methods: In August 2010, questionnaires were sent to all residents aged >= 65 years in three municipalities in Okayama prefecture (n = 21232), and 13929 questionnaires were returned (response rate: 65.6%). Social capital was measured from survey responses to questions on participation in six different types of groups: a) the elderly club or sports/hobby/culture circle; b) alumni association; c) political campaign club; d) citizen's group or environmental preservation activity; e) community association; and f) religious organization. Participant perception of group homogeneity (gender, age, and previous occupation) was used to divide social capital into bonding or bridging. Odds ratios (ORs) and 95% confidence intervals (CIs) for poor self-rated health were calculated.Results: A total of 11146 subjects (4441 men and 6705 women) were available for the analysis. Among men, bonding and bridging social capital were inversely associated with poor self-rated health (high bonding social capital; OR: 0.55, 95% CI: 0.31-0.99; high bridging social capital; OR: 0.62, 95% CI: 0.48-0.81) after adjusting for age, educational attainment, smoking status, frequency of alcohol consumption, overweight, living arrangements, and type-D personality. The beneficial effect among women was more likely limited to bonding social capital (high bonding social capital; OR: 0.34, 95% CI: 0.12-1.00), and the association between bridging social capital and self-rated health was less clear (high bridging social capital; OR: 0.69, 95% CI: 0.44-1.07).Conclusions: Bonding/bridging social capital could have differential associations with self-rated health among the Japanese elderly depending on the individual's sex. Considering the lack of consensus on how to measure bonding and bridging social capital, however, we need to carefully assess the generalizability of our findings. Further research is warranted to identify health-relevant dimensions of social capital in different cultural or economic settings.

DOI： 10.1186/1471-2458-13-1189

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

We investigated the association between Type D personality, psychological distress, and self-ratings of poor health in elderly Japanese people. In August 2010, questionnaires were sent to all residents aged >= 65 in three municipalities (n = 21232) in Okayama Prefecture, Japan, and. 13929 questionnaires were returned (response rate: 65.6%). To assess mental and physical health outcomes, we used the Kessler Psychological Distress Scale and a single item question regarding perceived general health. We analyzed 9759 questionnaires to determine odds ratios (ORs) and 95% confidence intervals (CIs) for several health outcomes, adjusting for sex, age, smoking status, frequency of alcohol consumption, overweight status, educational attainment, socioeconomic status, and number of cohabiters. The multiple imputation method was employed for missing data regarding Type D personality. The prevalence of Type D personality in our sample was 46.2%. After adjusting for covariates, we found that participants with Type D personality were at 4-5 times the risk of psychological distress, and twice the risk of poor self-rated health. This association was stronger in participants aged 65-74 years (psychological distress; OR: 5.80, 95% CI: 4.96-6.78, poor self-rated health; OR: 2.84, 95% CI: 2.38-3.38) than in those aged over 75 years (psychological distress; OR: 4.54, 95% CI: 3.96-5.19, poor self-rated health; OR: 2.05, 95% CI: 1.79-2.34). Type D personality is associated with adverse health status among Japanese elderly people in terms of mental and physical risk; therefore, further research into the implications of this personality type is warranted.

DOI： 10.1371/journal.pone.0077918

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Objective:To examine which contextual features of the workplace are associated with social capital.Methods:This is a cohort study of 43,167 employees in 3090 Finnish public sector workplaces who responded to a survey of individual workplace social capital in 2000-02 (response rate 68%). We used ecometrics approach to estimate social capital of work units. Features of the workplace were work unit's demographic and employment patterns and size, obtained from employers' administrative records. We used multilevel-multinomial logistic regression models to examine cross-sectionally whether these features were associated with social capital between individuals and work units. Fixed effects models were used for longitudinal analyses in a subsample of 12,108 individuals to examine the effects of changes in workplace characteristics on changes in social capital between 2000 and 2004.Results:After adjustment for individual characteristics, an increase in work unit size reduced the odds of high levels of individual workplace social capital (odds ratio 0.94, 95% confidence interval 0.91-0.98 per 30-person-year increase). A 20% increase in the proportion of manual and male employees reduced the odds of high levels of social capital by 8% and 23%, respectively. A 30% increase in temporary employees and a 20% increase in employee turnover were associated with 11% (95% confidence interval 1.04-1.17) and 24% (95% confidence interval 1.18-1.30) higher odds of having high levels of social capital respectively). Results from fixed effects models within individuals, adjusted for time-varying covariates, and from social capital of the work units yielded consistent results.Conclusions:These findings suggest that workplace social capital is contextually patterned. Workplace demographic and employment patterns as well as the size of the work unit are important in understanding variations in workplace social capital between individuals and workplaces. © 2013 Oksanen et al.

DOI： 10.1371/journal.pone.0065846

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OXFORD UNIV PRESS INC  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Background: Despite advances in our understanding of the countercyclical association between economic contraction and suicide, less is known about the levels of and changes in inequalities in suicide. The authors examined social and geographical inequalities in suicide in Japan from 1975 through 2005.Methods: Based on quinquennial vital statistics and census data, the authors analyzed the entire population aged 25-64 years. The total number of suicides was 75,840 men and 30,487 women. For each sex, the authors estimated odds ratios (ORs) and 95% credible intervals (CIs) for suicide using multilevel logistic regression models with "cells'' (cross-tabulated by age and occupation) at level 1, seven different years at level 2, and 47 prefectures at level 3. Prefecture-level variance was used as an estimate of geographical inequalities in suicide.Results: Adjusting for age and time-trends, the lowest odds for suicide was observed among production process and related workers (the reference group) in both sexes. The highest OR for men was 2.52 (95% CI: 2.43, 2.61) among service workers, whereas the highest OR for women was 9.24 (95% CI: 7.03, 12.13) among security workers. The degree of occupational inequalities increased among men with a striking change in the pattern. Among women, we observed a steady decline in suicide risk across all occupations, except for administrative and managerial workers and transport and communication workers. After adjusting for individual age, occupation, and time-trends, prefecture-specific ORs ranged from 0.76 (Nara Prefecture) to 1.36 (Akita Prefecture) for men and from 0.79 (Kanagawa Prefecture) to 1.22 (Akita Prefecture) for women. Geographical inequalities have increased primarily among men since 1995.Conclusions: The present findings demonstrate a striking temporal change in the pattern of social inequalities in suicide among men. Further, geographical inequalities in suicide have considerably increased across 47 prefectures, primarily among men, since 1995.

DOI： 10.1371/journal.pone.0063443

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Despite accumulating evidence of associations between social capital and health in public health research, a criticism of the field has been that researchers have exclusively focused on concepts of social cohesion to the exclusion of individual-level approaches. In the present study, we evaluated the association between social capital measured by the Resource Generator (an individual-level assessment of access to social capital) and self-rated health among Japanese population in a cross-sectional study. A postal survey of 4000 randomly selected residents in Okayama City (western Japan) was conducted in February 2009. We divided the overall scores from the Resource Generator Japan scale into quartiles. Odds ratios (ORs) and 95% confidence intervals (CIs) for self-rated health were calculated separately by sex. Individuals with the highest quartile of scores had significantly lower odds of poor health compared to the lowest group after covariate adjustment among both men and women (men; OR: 0.45, 95% CI: 0.24-0.86, women; OR: 0.44, 95% CI: 0.25-0.79, respectively) and there were also significant dose-response relationships. In the sub-domains of Resource Generator Japan scale, a differential pattern was observed by sex. Women showed a clear dose response relationship with health across all four sub-scales (domestic resources, expert advice, personal skills, and problem solving resources). In contrast, only the domain of expert advice exhibited a strong association with men's health. Among both men and women individual-level social capital measured by the Resource Generator was related to reduced odds of poor health even after taking into account individual confounders. Although we cannot exclude reverse causation due to the cross-sectional design, our study adds to the accumulating evidence of the potential utility of the Resource Generator for evaluating the relationship between individual-level access to social capital and health. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.socscimed.2013.02.027

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

The purpose of this study was to examine the association between shift work and diabetes mellitus by separating shift workers according to the intensity of their shift work (seasonal shift work and continuous shift work). Between May and October 2009, we collected data from annual health checkups and questionnaires at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate: 96.2%, men/women = 1,314/287). Diabetes mellitus was defined as hemoglobin Alc &gt;= 6.5% and fasting blood sugar &gt;= 126 mg/dl. After exclusions, which included all the women and clerical workers because they did not work in shifts, we analyzed 475 skilled male workers. After adjusting for age, smoking status, frequency of alcohol consumption, and cohabitation status, odds ratios for diabetes mellitus were 0.98 (95% confidence interval [CI]: 0.28-4.81) and 2.10 (95% CI: 0.77-5.71) among seasonal shift workers and continuous shift workers, respectively, compared with non-shift workers. In an age-stratified analysis (&lt; 45 years vs. &gt;= 45 years), the association between continuous shift work and diabetes mellitus was more pronounced among older participants. Compared with non-shift workers, the risk of diabetes mellitus was increased among continuous shift workers, whereas its effect is limited among seasonal shift workers.

DOI： 10.18926/AMO/49254

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Background: We examined how crossover therapy might affect the association between progression-free survival (PFS) and overall survival (OS) in non-small cell lung cancer (NSCLC).Methods: We extracted PFS- and OS-hazard ratios (HRs) in phase III trials of molecular-targeted agents for advanced NSCLC. Their relationship was modeled in a linear function with the coefficient of determination (R-squared) to assess the correlation between PFS and OS.Results: Thirty-four trials with 35 pairs for the investigational and reference arms were identified (24,158 patients). Overall, there was little correlation between PFS- and OS-HRs (R-squared = 0.14), suggesting PFS-HR could account only for 14% of variation in OS-HR The median proportion of crossover therapy per trial was 20%. If patients seldom crossed over (none or <1%), the association between PFS- and OS-HRs was strong (R-squared = 0.69). When the proportion of crossover was >= 1%, however, R-squared declined considerably (>= 1% to <20% crossover, R-squared = 0.27; >= 20% to <40%, R-squared = 0.06; and >= 40%, R-squared = 0.27).Conclusions: A PFS advantage seldom is associated with an OS advantage any longer. Our analysis suggests this is due to a high level of crossover now that an increasing number of active agents are available for NSCLC. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.lungcan.2012.10.007

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Background: Multilevel analyses are ideally suited to assess the effects of ecological (higher level) and individual (lower level) exposure variables simultaneously. In applying such analyses to measures of ecologies in epidemiological studies, individual variables are usually aggregated into the higher level unit. Typically, the aggregated measure includes responses of every individual belonging to that group (i.e. it constitutes a self-included measure). More recently, researchers have developed an aggregate measure which excludes the response of the individual to whom the aggregate measure is linked (i.e. a self-excluded measure). In this study, we clarify the substantive and technical properties of these two measures when they are used as exposures in multilevel models.Methods: Although the differences between the two aggregated measures are mathematically subtle, distinguishing between them is important in terms of the specific scientific questions to be addressed. We then show how these measures can be used in two distinct types of multilevel models-self-included model and self-excluded model-and interpret the parameters in each model by imposing hypothetical interventions. The concept is tested on empirical data of workplace social capital and employees' systolic blood pressure.Results: Researchers assume group-level interventions when using a self-included model, and individual-level interventions when using a self-excluded model. Analytical re-parameterizations of these two models highlight their differences in parameter interpretation. Cluster-mean centered self-included models enable researchers to decompose the collective effect into its within-and between-group components. The benefit of cluster-mean centering procedure is further discussed in terms of hypothetical interventions.Conclusions: When investigating the potential roles of aggregated variables, researchers should carefully explore which type of model-self-included or self-excluded-is suitable for a given situation, particularly when group sizes are relatively small.

DOI： 10.1371/journal.pone.0051717

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Background: The link between long working hours and health has been extensively studied for decades. Despite global concern regarding metabolic syndrome, however, no studies to date have solely evaluated the relationship between long working hours and that syndrome. We therefore examined the association between long working hours and metabolic syndrome in a cross-sectional study.Methods: Between May and October 2009, we collected data from annual health checkups and questionnaires from employees at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate: 96.2%; 1,314 men, 287 women). After exclusions, including women because of a lack of overtime work, the analysis was performed for 933 men. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for metabolic syndrome. Further, we conducted a stratified analysis by age-group (<40 years vs. >= 40 years).Results: Metabolic syndrome was identified in 110 workers (11.8%). We observed a positive association between working hours and metabolic syndrome after adjusting for age, occupation, shift work, smoking status, frequency of alcohol consumption, and cohabiting status. Compared with subjects who worked 7-8 h/day, multivariate ORs for metabolic syndrome were 1.66 (95% CI, 0.91-3.01), 1.48 (95% CI, 0.75-2.90), and 2.32 (95% CI, 1.04-5.16) for those working 8-9 h/day, 9-10 h/day, and >10 h/day, respectively. Similar patterns were obtained when we excluded shift workers from the analysis. In age-stratified analysis, the corresponding ORs among workers aged >= 40 years were 2.02 (95% CI, 1.04-3.90), 1.21 (95% CI, 0.53-2.77), and 3.14 (95% CI, 1.24-7.95). In contrast, no clear association was found among workers aged <40 years.Conclusions: The present study suggests that 10 h/day may be a trigger level of working hours for increased risk of metabolic syndrome among Japanese male workers.

DOI： 10.1186/1471-2458-12-395

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

When one discusses the dynamic changes in human health over time, one innately conceptualizes time from the three different, but related perspectives - age, period, and cohort. To determine their separate contributions to health outcomes, age-period-cohort analyses have been used for the past 80 years. This commentary aims to provide some insight into this analytical method by distinguishing the concept of time in terms of composition and context. To demonstrate, the author uses hypothetical nested data structures of age-period-cohort analyses in the two types of individual-level data, i.e., repeated cross-sectional survey and longitudinal data on the same individuals. The conceptual distinctions between composition and context have profound implications of hypothetical interventions in age-period-cohort analyses. Age is a compositional variable, and a hypothetical intervention to change age is at the individual level. By contrast, both period and cohort are contexts, and thus two distinct types of hypothetical interventions can be envisaged to examine their contextual effects. On a related issue, the author also discusses manipulability of time. Although time is a significant context in biomedical science, it is not the only context. In this commentary, context is proposed to be classified into three fundamental dimensions - relational, spatial, and temporal. Inattention to the contextual triad leads to a biased and precarious knowledge base for public health action, and the continuing flow of performance over time is an intrinsic component of improving our understanding of multilevel causal inference in the new era of eco-epidemiology. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.socscimed.2012.03.036

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Background: A recent study from Japan suggested that geographic inequalities in all-cause premature adult mortality have increased since 1995 in both sexes even after adjusting for individual age and occupation in 47 prefectures. Such variations can arise from compositional effects as well as contextual effects. In this study, we sought to further examine the emerging geographic inequalities in all-cause mortality, by exploring the relative contribution of composition and context in each prefecture.Methods: We used the 2005 vital statistics and census data among those aged 25 or older. The total number of decedents was 524,785 men and 455,863 women. We estimated gender-specific two-level logistic regression to model mortality risk as a function of age, occupation, and residence in 47 prefectures. Prefecture-level variance was used as an estimate of geographic inequalities in mortality, and prefectures were ranked by odds ratios (ORs), with the reference being the grand mean of all prefectures (value = 1).Results: Overall, the degree of geographic inequalities was more pronounced when we did not account for the composition (i.e., age and occupation) in each prefecture. Even after adjusting for the composition, however, substantial differences remained in mortality risk across prefectures with ORs ranging from 0.870 (Okinawa) to 1.190 (Aomori) for men and from 0.864 (Shimane) to 1.132 (Aichi) for women. In some prefectures (e. g., Aomori), adjustment for composition showed little change in ORs, while we observed substantial attenuation in ORs in other prefectures (e. g., Akita). We also observed qualitative changes in some prefectures (e. g., Tokyo). No clear associations were observed between prefecture-level socioeconomic status variables and the risk of mortality in either sex.Conclusions: Geographic disparities in mortality across prefectures are quite substantial and cannot be fully explained by differences in population composition. The relative contribution of composition and context to health inequalities considerably vary across prefectures.

DOI： 10.1371/journal.pone.0039876

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Objective: To evaluate the association between proximity to a health center and early childhood mortality in Madagascar, and to assess the influence of household wealth, maternal educational attainment, and maternal health on the effects of distance.Methods: From birth records of subjects in the Demographic and Health Survey, we identified 12565 singleton births from January 2004 to August 2009. After excluding 220 births that lacked global positioning system information for exposure assessment, odds ratios (ORs) and their 95% confidence intervals (CIs) for neonatal mortality and infant mortality were estimated using multilevel logistic regression models, with 12345 subjects (level 1), nested within 584 village locations (level 2), and in turn nested within 22 regions (level 3). We additionally stratified the subjects by the birth order. We estimated predicted probabilities of each outcome by a three-level model including cross-level interactions between proximity to a health center and household wealth, maternal educational attainment, and maternal anemia.Results: Compared with those who lived >1.5-3.0 km from a health center, the risks for neonatal mortality and infant mortality tended to increase among those who lived further than 5.0 km from a health center; the adjusted ORs for neonatal mortality and infant mortality for those who lived >5.0-10.0 km away from a health center were 1.36 (95% CI: 0.92-2.01) and 1.42 (95% CI: 1.06-1.90), respectively. The positive associations were more pronounced among the second or later child. The distance effects were not modified by household wealth status, maternal educational attainment, or maternal health status.Conclusions: Our study suggests that distance from a health center is a risk factor for early childhood mortality (primarily, infant mortality) in Madagascar by using a large-scale nationally representative dataset. The accessibility to health care in remote areas would be a key factor to achieve better infant health.

DOI： 10.1371/journal.pone.0038370

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OXFORD UNIV PRESS INC  

DOI： 10.1371/journal.pone.0051717

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BMJ  

Background Few studies have examined the potential difference in the relationship between bonding versus bridging social capital and health outcomes. We sought to examine the association between these different types of social capital and self-rated health in a population-based study.Methods In February 2009, 4000 residents of Okayama City (aged 20-80 y) were randomly selected for a survey on social capital and health. The survey asked about participation in six different types of associations: Parents and Teachers Association, sports clubs, alumni associations, political campaign clubs, citizen's groups and community associations. We distinguished between bonding and bridging social capital by asking participants about their perceived homogeneity (with respect to gender, age and occupation) of the groups they belonged to. ORs and 95% CIs for poor health were calculated.Results Bridging social capital (ie, participation in groups involving people from a diversity of backgrounds) was inversely associated with poor health in both sexes and women appeared to benefit more than men. Compared to those who reported zero participation, high bridging social capital was associated with a reduced odds of poor health (OR 0.25, 95% CI 0.11 to 0.55) in women after controlling for demographic variables, socioeconomic status, smoking habit and overweight. By contrast, bonding social capital was not consistently associated with better health in either gender.Conclusions The present study suggests that bonding and bridging social capital have differential associations with health and that the two forms of social capital need to be distinguished in considering interventions to promote health.

DOI： 10.1136/jech.2010.115592

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Objective: The association between workplace factors and the development of hypertension remains uncertain. We examined the risk of hypertension as a function of workplace social capital, that is, social cohesion, trust and reciprocity in the workplace.Methods: A total of 11 777 male and 49 145 female employees free of chronic hypertension at baseline in 2000-2004 were followed up for incident hypertension until the end of 2005 (the Finnish Public Sector Study). We used survey responses from the participants and their coworkers in the same work unit to assess workplace social capital at baseline. Follow-up for incident hypertension was based on record linkage to national health registers (mean follow-up 3.5 years, 1424 incident hypertension cases).Results: Male employees in work units characterized by low workplace social capital were 40-60% more likely to develop chronic hypertension compared to men in work units with high social capital [age-adjusted hazard ratio 1.57, 95% confidence interval (CI) 1.15-2.14 for self-assessed social capital and 1.41, 95% CI 1.01-1.97 for coworkers' assessment]. According to path analysis adjusted for covariates, the association between low self-reported social capital and hypertension was partially mediated by obesity (P for pathway = 0.02) and alcohol consumption (P = 0.03). For coworker-assessed social capital, the corresponding mediation pathways did not reach statistical significance (P = 0.055 and 0.22, respectively). No association between workplace social capital and hypertension was found for women.Conclusion: These data suggest that low self-reported workplace social capital is associated with increased near-term risk of hypertension in men in part due to unhealthy lifestyle.

DOI： 10.1097/hjh.0b013e32835377ed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Objectives: A few studies have revealed the impact of neighborhood social capital on oral health among young people. We sought to examine the associations of social capital in three settings (families, neighborhoods, and schools) with self-rated oral health among a sample of college students in Japan. Methods: Cross-sectional survey of 967 students in Okayama University, aged 18 and 19 years, was carried out. Logistic regression was used to examine the associations of poor self-rated oral health with perceptions of social capital, adjusting for self-perceived household income category and oral health behaviors. Results: The prevalence of subjects with poor self-rated oral health was 22%. Adjusted for gender, self-perceived household income category, dental fear, toothbrush frequency, and dental floss use, poor self-rated oral health was significantly associated with lower level of neighborhood trust [odds ratio (OR) 2.22; 95% confidence interval (CI): 1.40-3.54] and lower level of vertical trust in school (OR 1.71; 95% CI: 1.05-2.80). Low informal social control was unexpectedly associated with better oral health (OR 0.54; 95% CI: 0.34-0.85). Conclusion: The association of social capital with self-rated oral health is not uniform. Higher trust is associated with better oral health, whereas higher informal control in the community is associated with worse oral health.

DOI： 10.1111/j.1600-0528.2011.00642.x

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

It has been noted that there is ambiguity in the expression "attributable fraction," and epidemiologic literature has drawn a distinction between "excess fraction" and "etiologic fraction." These quantities do not necessarily approximate one another, and the etiologic fraction is not generally estimable without strong biologic assumptions. In previous studies, researchers have explained the relations between excess and etiologic fractions in the potential-outcome framework, and few authors have explained the relations between these concepts by showing the correspondence between the potential-outcome model and the sufficient-cause model. In this article, the authors thoroughly clarify the conceptual relations between excess, attributable, and etiologic fractions by explicating the correspondence between these 2 models. In so doing, the authors take into account the potential completion time of each sufficient cause, which contributes to further insight to clarify the 2 types of etiologic fraction, i.e., accelerating etiologic proportion and total etiologic proportion. These 2 measures cannot be distinguished in epidemiologic data, and the differences might be subtle. However, they are closely related to a very fundamental issue of causal inference, that is, how researchers define etiology. Further, the authors clarify the relation between 3 distinct assumptions-positive monotonicity, no preventive action (or sufficient-cause positive monotonicity), and no preventive sequence.

DOI： 10.1093/aje/kwr333

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Objectives: To examine trends in social and geographic inequalities in all-cause premature adult mortality in Japan.Design: Observational study of the vital statistics and the census data.Setting: Japan.Participants: Entire population aged 25 years or older and less than 65 years in 1970, 1975, 1980, 1985, 1990, 1995, 2000 and 2005. The total number of decedents was 984 022 and 532 223 in men and women, respectively.Main outcome measures: For each sex, ORs and 95% Cls for mortality were estimated by using multilevel logistic regression models with 'cells' (cross-tabulated by age and occupation) at level 1, 8 years at level 2 and 47 prefectures at level 3. The prefecture-level variance was used as an estimate of geographic inequalities of mortality.Results: Adjusting for age and time-trends, compared with production process and related workers, ORs ranged from 0.97 (95% Cl 0.96 to 0.98) among administrative and managerial workers to 2.22 (95% Cl 2.19 to 2.24) among service workers in men. By contrast, in women, the lowest odds for mortality was observed among production process and related workers (reference), while the highest OR was 12.22 (95% Cl 11.40 to 13.10) among security workers. The degree of occupational inequality increased in both sexes. Higher occupational groups did not experience reductions in mortality throughout the period and was overtaken by lower occupational groups in the early 1990s, among men. Conditional on individual age and occupation, overall geographic inequalities of mortality were relatively small in both sexes; the ORs ranged from 0.87 (Okinawa) to 1.13 (Aomori) for men and from 0.84 (Kanagawa) to 1.11 (Kagoshima) for women, even though there is a suggestion of increasing inequalities across prefectures since 1995 in both sexes.Conclusions: The present findings suggest that both social and geographic inequalities in all-cause mortality have increased in Japan during the last 3 decades.

DOI： 10.1136/bmjopen-2011-000425

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Does Open-air Exposure to Volatile Organic Compounds near a Plastic Recycling Factory Cause Health Effects?: Takashi YORIFUJI, et al. Department of Human Ecology, Okayama University Graduate School of Environmental Sciences-Objectives: After a plastic reprocessing factory began to operate in August 2004, the residents around the factory in Neyagawa, Osaka, Japan, began to complain of symptoms. Therefore, we conducted an exposure assessment and a population-based epidemiological study in 2006. Methods: To assess exposure, volatile organic compounds (VOCs) and total VOCs were measured at two locations in the vicinity of the factory. In the population-based study, a total of 3,950 residents were targeted. A self-administered questionnaire was used to collect information about subjects' mucocutaneous or respiratory symptoms. Using logistic regression models, we compared the prevalence of symptoms in July 2006 by employing the farthest area from the factory as a reference, and prevalence odds ratios (PORs) and their 95% confidence intervals (Cis) were estimated. Results: The concentration of total VOCs was higher in the vicinity of the factory. The prevalence of mucocutaneous and respiratory symptoms was the highest among the residents in the closest area to the factory. Some symptoms were significantly increased among the residents within 500 m of the factory compared with residents of an area 2800 m from the factory: e.g., sore throat (POR=3.2, 95% CI: 1.3-8.0), eye itch (POR=3.0, 95% CI: 1.5-6.0), eye discharge (POR=6.0, 95% CI: 2.3-15.9), eczema (POR=3.0, 95% CI: 1.1-7.9) and sputum (POR=2.4, 95% CI: 1.1-5.1). Conclusions: Despite of the limitations of this study, these results imply a possible association of open-air VOCs with mucocutaneous and respiratory symptoms. Because this kind of plasticre cycling factory only recently came into operation, more attention should be paid to the operation of plastic recycling factories in the environment. (J Occup Health 2012; 54: 79-87)

DOI： 10.1539/joh.11-0202-oa

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Maternal Working Hours and Early Childhood Overweight in Japan: A Population-based Study: Toshiharu MITSUHASHI, et al. Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Objectives: There has been a growing concern that maternal employment could have adverse or beneficial effects on children's health. Although recent studies demonstrated that maternal employment was associated with a higher risk of childhood overweight, the evidence remains sparse in Asian countries. We sought to examine the relationship between maternal working hours and early childhood overweight in a rural town in Okayama Prefecture. Methods: In February 2008, questionnaires were sent to parents of all preschool children aged >= 3 yr in the town to assess maternal working status (working hours and form of employment), children's body mass index, and potential confounders. Childhood overweight was defined following the age and sex-specific criteria of the International Obesity Task Force. Odds ratios (ORs) and 95% confidence intervals (CIs) for childhood overweight were estimated in a logistic regression. We used generalized estimating equations with an exchangeable correlation matrix, considering the correlation between siblings. Results: We analyzed 364 preschool children. Adjusting for each child's characteristics (age, sex), mother's characteristics (age, obesity, educational attainment, smoking status, and social participation), and family's characteristics (number of siblings), children whose mothers work <8 h/day had a substantially lower risk for being overweight (OR: 0.28, 95% CI: 0.09, 0.93) compared with children of non-working mothers, whereas the relationship was less pronounced among children whose mothers work >= 8 h/day (OR: 0.71, 95% CI: 0.19, 2.68). We observed similar patterns in a stratified analysis by the form of maternal employment. Conclusion: Short maternal working hours are associated with a lower odds of early childhood overweight. (J Occup Health 2012; 54: 25-33)

DOI： 10.1539/joh.11-0100-oa

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0b013e3182319159

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

The aim of the present study was to assess the diagnostic usefulness of Fluorine-18 fluorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) in the prediction of local recurrence of malignant lung tumors by analyzing the pre-radiofrequency ablation (RFA) maximal standardized uptake value (SUVmax). We performed a historical cohort study of consecutive malignant lung tumors treated by RFA from January 2007 to May 2008 at Okayama University Hospital. We selected only lung tumors examined by PET/CT within 90 days before RFA and divided them (10 primary and 29 metastatic) into 3 groups according to their tertiles of SUVmax. We calculated recurrence odds ratios in the medium group and the high group compared to the low group using multivariate logistic analysis. After we examined the relationship between SUVmax and recurrence in a crude model, we adjusted for some factors. Tumors with higher SUVmax showed higher recurrence odds ratios (medium group; 1.84, high group; 4.14, respectively). The tumor size also increased the recurrence odds ratio (2.67); we thought this was mainly due to selection bias because we excluded tumors less than 10 mm in diameter. This study demonstrated the pre-RFA SUVmax in PET/CT may be a prognostic factor for local recurrence of malignant lung tumors.

DOI： 10.18926/AMO/47265

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Background: While hypertension is a common and treatable health problem, adherence to antihypertensive medication remains a challenge. This study examines the hypothesis that workplace social capital may influence adherence to antihypertensive medication among hypertensive employees.Methodology/Principal Findings: We linked survey responses to nationwide pharmacy records for a cohort of 3515 hypertensive employees (mean age 53.9 years, 76% women) who required continuous antihypertensive drug therapy (the Finnish Public Sector study). A standard scale was used to measure workplace social capital from co-workers' assessments and self-reports in 2000-2004. Non-adherence to antihypertensive medication was determined based on the number of days-not-treated at the year following the survey using comprehensive prescription records. Negative binomial regression models were conducted adjusting for socio-demographic characteristics, duration of hypertension, behaviour-related risk factors, and co-morbid conditions. The overall rate of days-not-treated was 20.7 per person-year (78% had no days-not-treated). Higher age, obesity, and presence of somatic co-morbidities were all associated with better adherence, but this was not the case for co-worker-assessed or self-reported workplace social capital. The rate of days-not-treated was 19.7 per person-year in the bottom fourth of co-worker-assessed workplace social capital, compared to 20.4 in the top fourth. The corresponding rate ratio from the fully-adjusted model was 0.95 (95% confidence interval (CI) 0.58-1.56). In a subgroup of 907 new users of antihypertensive medication this rate ratio was 0.98 (95% CI 0.42-2.29).Conclusions/Significance: We found no consistent evidence to support the hypothesized effect of workplace social capital on adherence to drug therapy among employees with chronic hypertension.

DOI： 10.1371/journal.pone.0024732

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Public Health Association  

Objectives. We examined the association between workplace social capital and all-cause mortality in a large occupational cohort from Finland.Methods. We linked responses of 28043 participants to surveys in 2000 to 2002 and in 2004 to national mortality registers through 2009. We used repeated measurements of self- and coworker-assessed social capital. We carried out Cox proportional hazard and fixed-effects logistic regressions.Results. During the 5-year follow-up, 196 employees died. A 1-unit increase in the mean of repeat measurements of self-assessed workplace social capital (range 1-5) was associated with a 19% decrease in the risk of all-cause mortality (age- and gender-adjusted hazard ratio [HR]=0.81; 95% confidence interval [CI) =0.66, 0.99). The corresponding point estimate for the mean of coworker-assessed social capital was similar, although the association was less precisely estimated (age- and gender-adjusted HR=0.77; 95% CI=0.50, 1.20). In fixed-effects analysis, a 1-unit increase in self-assessed social capital across the 2 time points was associated with a lower mortality risk (odds ratio=0.81; 95% CI=0.55, 1.19).Conclusions. Workplace social capital appears to be associated with lowered mortality in the working-aged population. (Am J Public Health. 2011;101: 1742-1748. doi:10.2105/AJPH.2011.300166)

DOI： 10.2105/ajph.2011.300166

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OXFORD UNIV PRESS INC  

DOI： 10.1007/s10654-011-9568-3

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OXFORD UNIV PRESS INC  

DOI： 10.1097/EDE.0b013e3181febc5c

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

The assessment of mediation and mechanism is one way to more deeply explore cause-effect relationships, providing a stronger test and explanation of the observed associations. Most previous studies have described direct and indirect effects in terms of potential outcomes and response types, exploring mediation analysis in the counterfactual (= potential-outcome) framework. A recent paper by Hafeman (Eur J Epidemiol 23(11):711-721, 2008) provided a conceptual description of mediation in the sufficient-component cause framework, and VanderWeele (Eur J Epidemiol 24(5):217-224, 2009) explored the distinctions and relationships between the concepts of mediation and mechanism. This study builds on this prior work and demonstrates that further insight can be given by elucidating the concepts of mediation and mechanism in the sufficient-component cause framework, distinguishing their operation from presence. The careful consideration of the concepts of mediation and mechanism can clarify the relationship between them. Then, the present article describes how investigators can identify mediation as well as mechanism by showing their correspondence with direct and indirect effects in the counterfactual framework. This study also demonstrates how a researcher can decompose the total effect into the effect due to mediated paths and the effect due to non-mediated paths in terms of the probabilities of background factors of sufficient causes.

DOI： 10.1007/s10654-011-9568-3

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Other Link： http://link.springer.com/article/10.1007/s10654-011-9568-3/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

Seasonal influenza infection is a major challenge in public health. The term "seasonal influenza" refers to the typical increase in the number of influenza patients in the winter season in temperature zones. However, it is not clear how environmental factors within a single flu season affect influenza infection in a human population. Therefore, we evaluated the effects of temperature and humidity in the 2006-7 flu season on the onset of seasonal influenza using a case-crossover study. We targeted patients who attended one pediatric clinic in Okayama city, Japan and who were diagnosed as being infected with the seasonal influenza virus. Using 2 references (time-stratified and symmetric bidirectional design), we estimated the effects of average temperature and relative humidity from the onset day (lag0) to 10 days before (lag10). The total number of subjects was 419, and their onset days ranged from 26 December 2006 to 30 April 2007. While the onset was significantly associated with lower temperature, relative humidity was not related. In particular, temperatures before the 3-day incubation period had higher-magnitude odds ratios. For example, the odds ratio and 95% confidence interval for average temperature at time lag 8 was 1.12 (1.08-1.17) per 1.0 degrees C decrease. Low environmental temperature significantly increased the risk of seasonal influenza onset within the 2006-7 winter season.

DOI： 10.18926/AMO/45268

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OKAYAMA UNIV MED SCHOOL  

There have been only 2 reports of a large-scale foodborne outbreak arising from Salmonella enterica serotype Braenderup infection worldwide. On August 9, 2008, an outbreak originating in boxed lunches occurred in Okayama, Japan. We conducted a cohort study of 786 people who received boxed lunches from a particular catering company and collected 644 questionnaires (response rate: 82%). Cases were defined as those presenting with diarrhea (&gt;= 4 times in 24h) or fever (&gt;= 38 degrees C) between 12 am on August 8 and 12 am on August 14. We identified 176 cases (women/men: 39/137); younger children (aged &lt; 10 years) appeared to more frequently suffer severe symptoms. Three food items were significantly associated with higher risk of illness; tamagotoji (soft egg with mixed vegetables and meat) (relative risk (RR): 11.74, 95% confidence interval (CI): 2.98-46.24), pork cooked in soy sauce (RR: 3.17, 95% CI: 1.24-8.10), and vinegared food (RR: 4.13, 95% CI: 1.60-10.63). Among them, only the RR of tamagotoji was higher when we employed a stricter case definition. Salmonella Braenderup was isolated from 5 of 9 sampled cases and 6 food handlers. It is likely that unpasteurized liquid eggs contaminated by Salmonella Braenderup and used in tamagotoji caused this outbreak.

DOI： 10.18926/AMO/45264

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

Purpose: The aim of this study was to evaluate the local efficacy of I-131 for F-18 fluorodeoxyglucose positron emission tomography (FDG PET)-positive lesions.
Methods: Whole-body FDG PET/CT was performed on 37 patients (55 cases: 16 men, 21 women; age range: 24-82 years; mean age +/- standard deviation: 60.5 +/- 16.0 years) with differentiated thyroid cancer after total thyroidectomy. The metastatic or recurrent lesions were divided into 5 categories: primary tumor bed, lymph node, lung, bone, and other. The well-defined lesions were measured on CT, and the sizes were compared before and after radioactive iodine therapy.
Results: The analysis was performed on 37 patients with 44 lesions (lymph node: 24, lung: 16, bone: 4). Sixteen lesions (70%) were increased and 7 (30%) showed no change or reduction when there was positive accumulation on FDG PET/CT and negative accumulation on I-131 (F(+)I(-)) group. In the positive accumulation for both FDG PET/CT and I-131 (F(+)I(+)) group, 5 lesions (63%) were increased and 3 (37%) showed no change or reduction. There was no significant difference for the tendency to increase in size between the F(+)I(-) and the F(+)I(+) groups.
Conclusions: Lesions which show positive accumulations on FDG PET/CT have a greater tendency to increase in size. FDG-avid lesions are resistant to radioactive iodine therapy with or without I-131 uptake.

DOI： 10.1097/RLU.0b013e318203bb6c

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0b013e3181febc5c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER IRELAND LTD  

Background: The relationship between poor performance status (PS) and toxicity during chemotherapy is controversial. We examined this for erlotinib monotherapy in non-small cell lung cancer (NSCLC) patients.
Patients and methods: Toxicity during the first month of therapy was recorded in 209 patients receiving erlotinib for NSCLC, and its association with PS was assessed.
Results: Of 209 patients, 52, 115, 30 and 12 had a PS of 0, 1, 2 and 3-4, respectively. Treatment was discontinued in 26% of patients within 1 month, with a higher rate in poorer PS patients (17%, 25%, 37% and 42%). Discontinuation was predominantly due to disease progression, rather than adverse events, in both the whole cohort (82% vs. 18%) and the poorest PS subgroup (100% vs. 0%). Three, two, and four patients with a PS of 1,2 and 3-4, respectively, died within 1 month; all six deaths of PS 2-4 patients were attributed to disease progression. Treatment interruption and dose reduction rates were similar among the subgroups. The principal adverse event was skin rash, with identical incidence in all PS subgroups.
Conclusions: Poor PS is unlikely to increase the risk for toxicity during erlotinib monotherapy, but was related to low compliance, probably because of disease progression rather than treatment-related toxicity. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.lungcan.2010.03.008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0b013e3181f32842

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: Social capital is hypothesized to be relevant to health promotion, and the association between community social capital and cigarette smoking has been examined. Individual-level social capital has been found to be associated with smoking cessation, but evidence remains sparse on the contextual effect of social capital and smoking. Further, evidence remains sparse on the association between smoking and social capital in the workplace, where people are spending an increasing portion of their daily lives. We examined the association between workplace social capital and smoking status among Japanese private sector employees.
Methods: We employed a two-stage stratified random sampling procedure. Of the total of 1,800 subjects in 60 companies, 1,171 (men/women; 834/337) employees (65.1%) were identified from 46 companies in Okayama in 2007. Workplace social capital was assessed in two dimensions; trust and reciprocity. Company-level social capital was based on inquiring about employee perceptions of trust and reciprocity among co-workers, and then aggregating their responses in order to calculate the proportion of workers reporting mistrust and lack of reciprocity. Multilevel logistic regression analysis was conducted using Markov Chain Monte Carlo methods to explore whether individual-and company-level social capital was associated with smoking. Odds ratios (ORs) and 95% credible intervals (CIs) for current smoking were obtained.
Results: Overall, 33.3% of the subjects smoked currently. There was no relationship between individual-level mistrust of others and smoking status. By contrast, one-standard deviation change in company-level mistrust was associated with higher odds of smoking (OR: 1.25, 95% CI: 1.06-1.46) even after controlling for individual-level mistrust, sex, age, occupation, educational attainment, alcohol use, physical activity, body mass index, and chronic diseases. No clear associations were found between lack of reciprocity and smoking both at the individual-and company-level.
Conclusions: Company-level mistrust is associated with higher likelihood of smoking among Japanese employees, while individual perceptions of mistrust were not associated. The link between lack of reciprocity and smoking was not supported either at the individual-or company-level. Further studies are warranted to examine the possible link between company-level trust and smoking cessation in the Japanese workplace.

DOI： 10.1186/1471-2458-10-489

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Background: To examine the association between individual-level social capital and physical activity.
Methodology/Principal Findings: In February 2009, data were collected in a population-based cross-sectional survey in Okayama city, Japan. A cluster-sampling approach was used to randomly select 4,000 residents from 20 school districts. A total of 2260 questionnaires were returned (response rate: 57.4%). Individual-level social capital was assessed by an item inquiring about perceived trust of others in the community (cognitive dimension of social capital) categorized as low trust (43.0%), mid trust (38.6%), and high trust (17.3%), as well as participation in voluntary groups (structural dimension of social capital), which further distinguished between bonding (8.9%) and bridging (27.1%) social capital. Using logistic regression, we calculated the odds ratios (ORs) and 95% confidence intervals (CIs) for physical inactivity associated with each domain of social capital. Multiple imputation method was employed for missing data. Among total participants, 68.8% were physically active and 28.9% were inactive. Higher trust was associated with a significantly lower odds of physical inactivity (OR = 0.58, 95% CI = 0.42-0.79) compared with low trust. Both bridging and bonding social capital were marginally significantly associated with lower odds of physical inactivity (bridging, OR = 0.79, 95% CI = 0.62-1.00; bonding, OR = 0.71, 95% CI = 0.48-1.03) compared with lack of structural social capital.
Conclusions/Significance: Low individual-level social capital, especially lower trust of others in the community, was associated with physical inactivity among Japanese adults.

DOI： 10.1371/journal.pone.0012135

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

DOI： 10.2147/copd.s10029

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MANEY PUBLISHING  

We investigated whether individuals exposed to asbestos by living near an asbestos-manufacturing facility experienced increased lung cancer mortality. We studied a neighborhood around such a plant in the central Japanese city of Hashima. From 1943 to 1991 this plant produced insulation and packing material using amosite- and chrysotile-type asbestos fibers. The study group was comprised of 577 households. We obtained demographic information by a questionnaire and determined the underlying cause of death for deceased household members from death certificates. Using hourly meteorological data from local observatories, we estimated relative asbestos concentrations in the plant's vicinity, determined the quartile boundaries, and designated each study subject's quartile of ambient exposure. Finally, we calculated standardized mortality ratios to evaluate the association of residential asbestos with lung cancer risk. Our findings strongly suggest that neighborhood asbestos exposure can increase the risk of lung cancer mortality in men and probably in women.

DOI： 10.1179/107735210799160110

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

While the majority of studies of social capital and health have focused on conceptualizing social capital at the geographic level, evidence remains sparse on workplace social capital. We examined the association between workplace social capital and health status among Japanese private sector employees in a cross-sectional study. By employing a two-stage stratified random sampling procedure, 1147 employees were identified from 46 companies in Okayama in 2007. Workplace social capital was measured based on two components; trust and reciprocity. Company-level social capital was based on aggregating employee responses and calculating the proportion of workers reporting mistrust and lack of reciprocity. Multilevel logistic regression analysis was conducted using Markov Chain Monte Carlo methods to explore whether individual- and company-level mistrust and lack of reciprocity were associated with poor self-rated health. Odds ratios (ORs) and 95% credible intervals (as) for poor health were obtained for each variable. Workers reporting individual-level mistrust and lack of reciprocity had approximately double the odds of poor health even after controlling for sex, age, occupation, educational attainment, smoking, alcohol use, physical activity, body mass index, and chronic diseases. While we found some suggestion of a contextual association between company-level mistrust and poor health, no association was found between company-level lack of reciprocity and health. Despite the thorough examination of cross-level interaction terms between company-level social capital and individual characteristics, no clear patterns were observed. Individual perceptions of mistrust and lack of reciprocity at work have adverse effects on self-rated health among Japanese workers. Although the present study possibly suggests the contextual effect of workplace mistrust on workers' health, the contextual effect of workplace lack of reciprocity was not supported. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.socscimed.2010.01.014

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Background: Physical activity recommendations for older adults with poor health needs to be understood.
Purpose: This study aims to examine the association between the frequency of physical activity and mortality among a sample of elderly subjects, most of whom were under treatment for pre-existing disease.
Methods: Data on the frequency of leisure-time physical activity, walking for transportation, and non-exercise physical activity were obtained from a population-based cohort study in Shizuoka, Japan. Of the randomly selected 22,200 residents aged 65-84 years, 10,385 subjects were followed from 1999 to 2006 and analyzed. Hazard ratios (HRs) and 95% CIs were obtained for all-cause; cardiovascular disease (CVD); and cancer mortality, after adjusting for covariates such as preexisting disease(s) A subgroup analysis that was restricted to subjects under treatment for preexisting disease(s) at baseline was further conducted. Data were collected between 1999 and 2006, and all analyses were conducted in 2008 and 2009.
Results: Every physical activity was associated with a reduced risk of all-cause and CVD mortality, among not only the total sample but even those under treatment. The HRs for CVD mortality among participants with 5 or more days of non-exercise physical activity per week for the total sample and those with pre-existing disease(s) were 038 (95% CI=0.22, 0 55) and 0.35 (95% CI=0.24, 052), respectively, compared with no non-exercise physical activity. The association between physical activity and cancer mortality was not clear
Conclusions: This study suggests a protective effect of physical activity on all-cause and CVD mortality among Japanese elderly people with pre-existing disease (Am J Prev Med 2010;38(4) 410-418) (C) 2010 American Journal of Preventive Medicine

DOI： 10.1016/j.amepre.2009.12.033

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：B M J PUBLISHING GROUP  

Objectives The number of studies investigating the health effects of long-term exposure to air pollution is increasing, however, most studies have been conducted in Western countries. The health status of Asian populations may be different to that of Western populations and may, therefore, respond differently to air pollution exposure. Therefore, we evaluated the health effects of long-term exposure to traffic-related air pollution in Shizuoka, Japan.
Methods Individual data were extracted from participants of an ongoing cohort study. A total of 14 001 older residents, who were randomly chosen from all 74 municipalities of Shizuoka, completed questionnaires and were followed from December 1999 to March 2006. Individual nitrogen dioxide exposure data, as an index for traffic-related exposure, were modelled using a land use regression model. We assigned participants an estimated concentration of nitrogen dioxide exposure during 2000-2006. We then estimated the adjusted HR and their Cl for a 10 mu g/m(3) increase in exposure to nitrogen dioxide for all-cause or cause-specific mortality.
Results The adjusted HR for all-cause mortality was 1.02 (95% Cl 0.96 to 1.08). Regarding cause-specific mortality, the adjusted HR for cardiopulmonary mortality was 1.16 (95% Cl 1.06 to 1.26); in particular the adjusted HR for ischaemic heart disease mortality was 1.27 (95% Cl 1.02 to 1.58) and for pulmonary disease mortality it was 1.19 (95% Cl 1.02 to 1.38). Furthermore, among non-smokers, a 10 mu g/m(3) increase in nitrogen dioxide was associated with a higher risk for lung cancer mortality (HR 1.30, 95% Cl 0.85 to 1.93).
Conclusion Long-term exposure to traffic-related air pollution, indexed by nitrogen dioxide concentration, increases the risk of cardiopulmonary mortality, even in a population with a relatively low body mass index and increases the risk of lung cancer mortality in nonsmokers.

DOI： 10.1136/oem.2008.045542

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Association for Acute Medicine  

The fundamental statistical knowledge that is required in clinical studies is, first, being able to decide "Which test would be the best to use in which situation" when comparing basic attributes, and understanding logistic regression analysis as a form of multivariate analysis that is used to "adjust for confounding factors". In addition, because many clinical studies use survival time as their outcome, it is also important to learn about survival analysis. When comparing basic attributes, after determining whether the variables are "continuous variables" or "categorical variables", the decision as to which test to use depends on whether "2 groups" are going to be compared or "more than 3 groups" are going to be compared. Logistic regression analysis is often used when there are two outcome values, and it is possible to estimate the effect of exposure as an odds ratio. By contrast, with the Cox proportional hazard model, which is used in survival analyses, the effect of exposure can be estimated in the form of a hazard ratio. "Increasing the statistical knowledge required after studying epidemiology thoroughly" might be an efficient way to acquire knowledge about clinical studies in the midst of a busy clinical practice.

DOI： 10.3893/jjaam.20.851

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Other Link： http://search.jamas.or.jp/link/ui/2010080209

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

PURPOSE: To investigate the association between green tea consumption and mortality from all causes, cancer, and cardiovascular disease (CVD) among elderly people.METHODS: In a population-based, prospective cohort study, a total of 14,001 elderly residents (aged 65-84 years), randomly chosen from all 74 municipalities in Shizuoka, Japan, completed questionnaires that included items about frequency of green tea consumption. They were followed for up to 6 years, from December 1999 to March 2006. Consequently, 12,251 subjects were analyzed to estimate the hazard ratios (HRs) for all-cause mortality, cancer, and CVD.RESULTS: Among 64,002 person-years, 1,224 deaths were identified (follow-up rate, 71.6%). The multivariate HRs and 95% confidence intervals (CIs) for CVD mortality compared those who consumed seven or more cups per day with those who consumed less than one cup per day, were 0.24 (0.14-0-40), 0.30 (0.15-0.61), and 0.18 (0.08-0.40) for total participants, men, and women, respectively. Although green tea consumption was not inversely associated with cancer mortality, green tea consumption and colorectal cancer mortality were inversely associated with a moderate dose-response relationship.CONCLUSIONS: Green tea consumption is associated with reduced mortality from all causes and CVD. This study also suggests that green tea Could have protective effects against colorectal cancer. Ann Epidemiol 2009; 19:732-739. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.annepidem.2009.06.003

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：BMJ  

DOI： 10.1136/jech.2008.082453

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Society for Hygiene  

Confounding is frequently a primary concern in epidemiological studies. With the increasing complexity of hypothesized relationships among exposures, outcomes, and covariates, it becomes very difficult to present these hypotheses lucidly and comprehensively. Graphical models are of great benefit in this regard. In this article, we focuse on directed acyclic graphs (DAGs), and review their value for confounder selection, categorization of potential biases, and hypothesis specification. We also discuss the importance of considering causal structures before selecting the covariates to be included in a statistical model and the potential biases introduced by inappropriately adjusting statistical models for covariates. DAGs are nonparametric and qualitative tools for visualizing research hypotheses regarding an exposure, an outcome, and covariates. Causal structures represented in DAGs will rarely be perfectly "correct" owing to the uncertainty about the underlying causal relationships. Nevertheless, to the extent that using DAGs forces greater clarity about causal assumptions, we are able to consider key sources of bias and uncertainty when interpreting study results. In summary, in this article, we review the following three points. (1) Although researchers have not adopted a consistent definition of confounders, using DAGs and the rules of d-separation we are able to identify clearly which variables we must condition on or adjust for in order to test a causal hypothesis under a set of causal assumptions. (2) We also show that DAGs should accurately correspond to research hypotheses of interest. To obtain a valid causal interpretation, research hypotheses should be defined explicitly from the perspective of a counterfactual model before drawing DAGs. A proper interpretation of the coefficients of a statistical model for addressing a specific research hypothesis relies on an accurate specification of a causal DAG reflecting the underlying causal structure. Unless DAGs correspond to research hypotheses, we cannot reliably reach proper conclusions testing the research hypotheses. Finally, (3) we have briefly reviewed other approaches to causal inference, and illustrate how these models are connected.<br>

DOI： 10.1265/jjh.64.796

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Other Link： https://jlc.jst.go.jp/DN/JALC/00337274259?from=CiNii

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3893/jjaam.20.794

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)  

DOI： 10.1265/jjh.64.786

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Objective. To investigate the associations between sleep duration and mortality in the elderly by controlling for sleep quality.Method. Data were collected from participants in a cohort study in Shizuoka, Japan. A total of 14,001 elderly residents (aged 65-85 years), randomly chosen from all 74 municipalities in the prefecture. completed questionnaires that evaluated sleep duration, sleep complaints, and the use of hypnotics. Participants were followed from 1999 to 2006. We analyzed 11,395 subjects to estimate the hazard ratios (HR) for mortality from all causes and cardiovascular disease (CVD).Results. With 60,252 person-years, 1004 deaths were identified. While short sleep duration and mortality were not associated, longer sleep duration was associated with higher risk of mortality in both sexes. Compared with those who slept 7 h, the multivariate HR and 95% confidence interval of CVD mortality for those who slept >= 10 h was 1.95 (1.18-3.21) and, for those who slept <= 5 h, it was 1.10 (0.62-1.93). Although no clear association was found between sleep quality and mortality, long sleep duration was associated with higher risk of CVD mortality among those with poor sleep quality.Conclusion. Long sleep duration is associated with higher risk of CVD mortality among the elderly with poor sleep quality. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.ypmed.2009.06.016

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3893/jjaam.20.397

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Oseltamivir is a neuraminidase inhibitor that inhibits influenza virus proliferation, and is used as an antiviral drug against influenza A and B viruses. Recently, concerns have been raised about hallucinations, delirium, and abnormal activity after administration of oseltamivir for treatment of infection with influenza virus. A large epidemiologic study was conducted in Japan in the winter of 2006-2007 to assess the relationship between oseltamivir intake and adverse behaviors, and an interim report was released on 10 July 2008. In the report, the research group concluded that no positive associations were detected between oseltamivir intake and abnormal behaviors. However, the analytic method used in the study was flawed. A correct analysis (based on person-time) shows a rate ratio of 1.57 (95% confidence interval = 1.34-1.83). This example clearly illustrates the importance of person-time in the analysis of cohort studies.

DOI： 10.1097/ede.0b013e3181a3d3f6

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OXFORD UNIV PRESS INC  

DOI： 10.1016/j.ypmed.2009.06.016

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Association for Acute Medicine  

Comprehending academic theses (i.e., critical appraisal) is a fundamental technique that is necessary when conducting research: in recent days with the practice of EBM, it has become a prerequisite needed even by clinicians. A great many clinicians find understanding academic theses almost painful. However, the authors believe that acquiring a basic knowledge of epidemiology and studying the methods of writing academic theses are the best approach if one wishes to master a technique that will lead to an understanding of academic theses. For the fundamental knowledge of epidemiology, understanding epidemiological indices and outcome measures, which are necessary for quantitative estimation of the effects of exposure (treatment) on the outcome, as well as the research design that are a prerequisite in considering biases are extremely important. For an interpretation of academic theses, on the other hand, one's efficacy to read and understand academic theses improves dramatically if he understands the paragraph structure and learns to do "paragraph reading" (reading each paragraph consecutively). The best training is to read these academic theses while referring to various guidelines for writing papers.

DOI： 10.3893/jjaam.20.338

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Other Link： http://search.jamas.or.jp/link/ui/2009262363

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3893/jjaam.20.288

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Background: Large-scale methylmercury poisonings have occurred in Japan (Minamata and Niigata) and in Iraq. The current WHO threshold for adult exposure (hair level: 50 mu g/g) was based on evidence from Niigata, which included only acute and severe cases. That study leaves open the possibility of more subtle effects at lower exposure levels.Methods: The Shiranui sea had been contaminated in the 1950s by the discharge of methylmercury from a factory near Minamata.In 1960, the hair mercury content of 1694 residents living on the coastline of the Shiranui sea was measured by researchers from the Kumamoto Prefecture Institute for Health Research. Independently, in 1971, a population-based study to examine neurologic signs was conducted in the Minamata and Goshonoura areas, on the coastline of the Shiranui Sea, and the Ariake area (reference), by researchers at Kumamoto University. We identified 120 residents from exposed areas who were included in both datasets, plus 730 residents of Ariake (an unexposed area) who were also examined for neurologic signs.Results: Hair mercury levels were associated with perioral sensory loss in a dose-response relationship. The adjusted prevalence odds ratios and 95% confidence intervals for perioral sensory loss, compared with the lowest exposure category (0-10 mu g/g), were 4.5 (0.5-44), 9.1 (1.0-83), and 10 (0.9-110), for the dose categories >10 to 20, >20 to 50, and >50 mu g/g, respectively. The prevalence of all neurologic signs was higher in the exposure area than in Ariake.Conclusions: An increased prevalence of neurologic signs, especially perioral sensory loss, was found among residents with hair mercury content below 50 mu g/g.

DOI： 10.1097/ede.0b013e318190e73f

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1097/01.ede.0000340088.39958.8b

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Sciences-The effectiveness of Internet-based self-help programs for insomnia is still unclear. A randomized controlled trial was conducted to evaluate the effect of an Internet-based self-help program for better quality of sleep among adult workers. Forty-three volunteers were recruited and randomly assigned to either an intervention group (n=21) or a waiting-list group (n=22). The intervention group participated in a two-week Internet-based program, including selecting and daily practicing sleep-related target behaviors and monitoring those behaviors along with sleep quality. At the same time, each participant received automatically generated, personalized messages and reports both daily and weekly. A total of 12 intervention group participants and 18 waiting-list group participants completed questionnaires at baseline, post-intervention, and at a 3-wk follow-up. Subjective sleep quality was measured by a self-reported questionnaire developed for this study. The sleep quality score increased in the intervention group at post-intervention, with a significant interaction effect [F(1, 28)=5.19, p=0.031]. Sleep-related behaviors also greatly increased in the intervention group at post-intervention, with a significant interaction effect [F(1,28)=7.14, p=0.012]. Sleep-onset latency reduced in the intervention group at follow-up, with a marginally significant effect [F(1,28)=3.52, p=0.071]. The Internet-based self-help program improves subjective sleep quality and sleep-onset latency among adult workers.

DOI： 10.1539/joh.l7154

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

DOI： 10.1097/ede.0b013e31816379b1

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Responsible for pages：89–111   Language：Japanese Book type：Scholarly book

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J-GLOBAL

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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Symposium: New methods for an old epidemiologic problem: age, period, and cohorts effects. (Symposium chairs: Whitney Robinson, Katherine M. Keyes)

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：(公社)日本医学放射線学会  

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Language：English   Publisher：JAPAN SOC OCCUPATIONAL HEALTH  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

DOI： 10.1097/01.ede.0000391895.33567.d5

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DOI： 10.1097/01.ede.0000391894.33567.9c

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Other Link： http://search.jamas.or.jp/link/ui/2010214186

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：Japan Society for Occupational Health  

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J-GLOBAL

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Event date： 2023.1.21

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Venue：Kumamoto  

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Event date： 2022.12.1 - 2022.12.3

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Event date： 2022.11.5 - 2022.11.6

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Venue：Chicago, IL  

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Venue：Chicago, IL  

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Venue：San Diego, CA (online conference)  

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Venue：Matsumoto, Nagano  

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Event date： 2021.3.26 - 2021.3.28

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Venue：Yokohama  

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Event date： 2021.2.12 - 2021.2.14

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.1.27 - 2021.1.29

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Saga  

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Event date： 2020.12.16 - 2020.12.18

Language：English   Presentation type：Poster presentation  

Venue：Boston, MA (online conference)  

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Event date： 2020.12.16 - 2020.12.18

Language：English   Presentation type：Poster presentation  

Venue：Boston, MA (online conference)  

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Event date： 2020.11.19 - 2020.11.21

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kyoto  

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Event date： 2020.11.1 - 2020.11.3

Language：Japanese   Presentation type：Poster presentation  

Venue：Osaka  

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Event date： 2020.10.15 - 2020.10.17

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Okayama  

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Event date： 2020.8.23 - 2020.9.24

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yokohama  

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Event date： 2020.8.23 - 2020.9.24

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yokohama  

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Event date： 2020.8.23 - 2020.9.24

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yokohama  

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Event date： 2020.8.23 - 2020.9.24

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Yokohama  

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Event date： 2020.5.13 - 2020.5.16

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Asahikawa, Hokkaido  

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Event date： 2020.4.22 - 2020.4.24

Language：English   Presentation type：Poster presentation  

Venue：Oslo  

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Event date： 2019.11.21 - 2019.11.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.11.21 - 2019.11.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.11.21 - 2019.11.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.6.23 - 2019.6.26

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Portland, OR  

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Event date： 2019.6.18 - 2019.6.21

Language：English   Presentation type：Poster presentation  

Venue：Minneapolis, MN  

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Event date： 2019.5.22 - 2019.5.24

Language：English   Presentation type：Poster presentation  

Venue：Montreal  

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Event date： 2018.8.26 - 2018.8.30

Language：English   Presentation type：Poster presentation  

Venue：Ottawa  

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Event date： 2018.6.19 - 2018.6.22

Language：English   Presentation type：Poster presentation  

Venue：Baltimore, MD  

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Event date： 2018.5.22 - 2018.5.23

Language：English   Presentation type：Poster presentation  

Venue：Pittsburgh, PA  

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Event date： 2017.11.24 - 2017.11.26

Language：Japanese   Presentation type：Poster presentation  

Venue：Tokyo  

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Event date： 2017.6.20 - 2017.6.23

Language：English   Presentation type：Poster presentation  

Venue：Seattle, WA  

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Event date： 2017.5.23 - 2017.5.25

Language：English   Presentation type：Poster presentation  

Venue：Chapel Hill, NC  

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Event date： 2016.11.9 - 2016.11.12

Language：English   Presentation type：Poster presentation  

Venue：Vienna  

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Event date： 2016.9.1 - 2016.9.4

Language：English   Presentation type：Poster presentation  

Venue：Rome  

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Event date： 2016.9.1 - 2016.9.4

Language：English   Presentation type：Poster presentation  

Venue：Rome  

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Event date： 2016.9.1 - 2016.9.4

Language：English   Presentation type：Poster presentation  

Venue：Rome  

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Event date： 2016.7.23 - 2016.7.24

Language：Japanese   Presentation type：Poster presentation  

Venue：Kurashiki, Okayama  

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Event date： 2016.6.26 - 2016.6.29

Language：English   Presentation type：Poster presentation  

Venue：Sapporo, Hokkaido  

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Event date： 2016.6.21 - 2016.6.24

Language：English   Presentation type：Poster presentation  

Venue：Miami, FL  

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Event date： 2016.6.21 - 2016.6.24

Language：English   Presentation type：Poster presentation  

Venue：Miami, FL  

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Event date： 2016.3.2 - 2016.3.5

Language：English   Presentation type：Poster presentation  

Venue：Kathmandu  

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Event date： 2016.1.6 - 2016.1.7

Language：English   Presentation type：Symposium, workshop panel (nominated)  

Venue：Tokyo  

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Event date： 2015.11.4 - 2015.11.6

Language：Japanese   Presentation type：Poster presentation  

Venue：Nagasaki  

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Event date： 2015.11.4 - 2015.11.6

Language：Japanese   Presentation type：Poster presentation  

Venue：Nagasaki  

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Event date： 2015.10.14 - 2015.10.17

Language：English   Presentation type：Poster presentation  

Venue：Milan  

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Event date： 2015.10.14 - 2015.10.17

Language：English   Presentation type：Poster presentation  

Venue：Milan  

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Event date： 2015.8.30 - 2015.9.3

Language：English   Presentation type：Poster presentation  

Venue：Sao Paulo  

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Event date： 2015.6.16 - 2015.6.19

Language：English   Presentation type：Poster presentation  

Venue：Denver, CO  

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Event date： 2015.6.16 - 2015.6.19

Language：English   Presentation type：Poster presentation  

Venue：Denver, CO  

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Event date： 2015.6.16 - 2015.6.19

Language：English   Presentation type：Poster presentation  

Venue：Denver, CO  

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Event date： 2015.6.16 - 2015.6.19

Language：English   Presentation type：Poster presentation  

Venue：Denver, CO  

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Event date： 2015.5.13 - 2015.5.16

Language：Japanese   Presentation type：Poster presentation  

Venue：Osaka  

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Event date： 2015.3.5 - 2015.3.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Toyama  

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Event date： 2014.11.29 - 2014.12.2

Language：English   Presentation type：Poster presentation  

Venue：Shanghai  

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Event date： 2014.11.17 - 2014.11.18

Language：English   Presentation type：Oral presentation (invited, special)