Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 27, Issue 12
Displaying 1-7 of 7 articles from this issue
Review Article
  • Shamima Akter, Atsushi Goto, Tetsuya Mizoue
    2017 Volume 27 Issue 12 Pages 553-561
    Published: 2017
    Released on J-STAGE: October 12, 2017
    Supplementary material

    Cigarette smoking is the leading avoidable cause of disease burden. Observational studies have suggested an association between smoking and risk of type 2 diabetes mellitus (T2DM). We conducted a meta-analysis of prospective observational studies to investigate the association of smoking status, smoking intensity, and smoking cessation with the risk of T2DM in Japan, where the prevalence of smoking has been decreasing but remains high. We systematically searched MEDLINE and the Ichushi database to December 2015 and identified 22 eligible articles, representing 343,573 subjects and 16,383 patients with T2DM. We estimated pooled relative risks (RRs) using a random-effects model and conducted subgroup analyses by participant and study characteristics. Compared with nonsmoking, the pooled RR of T2DM was 1.38 (95% confidence interval [CI], 1.28–1.49) for current smoking (19 studies) and 1.19 (95% CI, 1.09–1.31) for former smoking (15 studies). These associations persisted in all subgroup and sensitivity analyses. We found a linear dose-response relationship between cigarette consumption and T2DM risk; the risk of T2DM increased by 16% for each increment of 10 cigarettes smoked per day. The risk of T2DM remained high among those who quit during the preceding 5 years but decreased steadily with increasing duration of cessation, reaching a risk level comparable to that of never smokers after 10 years of smoking cessation. We estimated that 18.8% of T2DM cases in men and 5.4% of T2DM cases in women were attributable to smoking. The present findings suggest that cigarette smoking is associated with an increased risk of T2DM, so tobacco control programs to reduce smoking could have a substantial effect to decrease the burden of T2DM in Japan.

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Original Articles
  • Keigo Saeki, Kenji Obayashi, Norio Kurumatani
    2017 Volume 27 Issue 12 Pages 562-567
    Published: 2017
    Released on J-STAGE: October 12, 2017

    Background: Excess mortality from cardiovascular disease during cold seasons is a worldwide issue. Although some physiologic studies suggests that platelet activation via cold exposure may cause an increased incidence of cardiovascular disease in winter, the influence of indoor cold exposure in real-life situations on platelet (PLT) count remains unclear.

    Methods: A cross-sectional study was conducted among 1095 elderly individuals. After obtaining a venous sample in the morning, indoor temperature of participants' home was measured every 10 min for 48 h. The mean indoor temperature while the participants stayed at home was calculated. All measurement was conducted during cold seasons (October to April) from 2010 to 2014.

    Results: The mean age of the 1095 participants was 71.9 years. They spent 87.3% of the day at home (20 h 27 min). A 1 °C lower daytime indoor temperature was associated with a significant increase in PLT count of 1.47 × 109/L (95% confidence interval, 0.39–2.56 × 109/L). Compared with the warmest tertile group (20.1 [standard deviation {SD}, 0.09] °C), the coldest group (11.7 [SD, 0.12] °C) showed a 5.2% higher PLT count (238.84 [SD, 3.30] vs. 226.48 [SD, 3.32] × 109/L; P = 0.01), even after adjusting for basic characteristics (age, gender, body weight, and smoking), antihypertensive medication, comorbidities (diabetes, estimated glomerular filtration rate), socioeconomic status (household income and education), day length, and outdoor temperature.

    Conclusions: We found a significant and independent association between lower indoor temperature and higher PLT count among elderly in winter.

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  • Defu Ma, Hiromichi Sakai, Chihiro Wakabayashi, Jong-Sook Kwon, Yoonna ...
    2017 Volume 27 Issue 12 Pages 568-573
    Published: 2017
    Released on J-STAGE: October 12, 2017

    Background: Noncommunicable disease (NCD) has become the leading cause of mortality and disease burden worldwide.

    Methods: A cross-sectional survey was carried out to investigate the prevalence of NCDs and risk factor control on dietary behaviors and dietary intake in China, Japan, and Korea.

    Results: There were significant differences among the three countries on the prevalence of hypertension (24.5% in China, 17.6% in Korea, and 15.2% in Japan), diabetes (8.9% in China, 5.7% in Korea, and 4.8% in Japan), hyperlipidemia (13.1% in China, 9.2% in Korea, and 6.9% in Japan), and angina pectoris (3.6% in China, 1.7% in Korea, and 1.5% in Japan). The prevalence rate of hypertension, diabetes, hyperlipidemia, and angina pectoris was highest in China and lowest in Japan. However, 82.2%, 48.4%, and 64.4% of Chinese, Koreans, and Japanese presented good dietary behavior, respectively. Multivariable logistic regression analysis found that sex, age, and marital status were predictors of good dietary behavior. In addition, in comparison with subjects without hypertension, diabetes, or hyperlipidemia, subjects with hypertension, diabetes, or hyperlipidemia significantly improved their dietary behaviors and controlled their intake of salt, sugar, and oil.

    Conclusions: The prevalence of NCDs and trends in major modifiable risk factor control in China, Korea, and Japan remain troubling. Public efforts to introduce healthy lifestyle changes and systematic NCDs prevention programs are necessary to reduce the epidemic of NCDs in these three Asian countries.

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  • Wei-Syun Hu, Cheng-Li Lin
    2017 Volume 27 Issue 12 Pages 574-577
    Published: 2017
    Released on J-STAGE: October 12, 2017

    Background: This study was conducted to evaluate the association between hemorrhoid and risk of incident peripheral artery occlusive disease (PAOD).

    Methods: Using the Taiwanese Longitudinal Health Insurance Database 2000, we compared the incident PAOD risk between the hemorrhoid and the non-hemorrhoid cohorts. Both of these cohorts were followed up from the index date until the date of PAOD diagnosis, withdrawal from the National Health Insurance program, or the end of 2011.

    Results: The mean follow-up period was 6.82 (standard deviation [SD], 3.22) and 6.70 (SD, 3.23) years in the hemorrhoid and non-hemorrhoid cohorts, respectively. The plot of the Kaplan–Meier analysis showed that, by the end of the 12-year follow-up period, the cumulative incidence of PAOD was significantly higher for the hemorrhoid cohort than for the non-hemorrhoid cohort (log-rank test: P < 0.001).

    Conclusions: A significantly increased PAOD risk in patients with hemorrhoids was found in this nationwide cohort study.

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  • Masaharu Nagata, Jun Hata, Yoichiro Hirakawa, Naoko Mukai, Daigo Yoshi ...
    2017 Volume 27 Issue 12 Pages 578-583
    Published: 2017
    Released on J-STAGE: October 12, 2017
    Supplementary material

    Background: Whether the intake of eicosapentaenoic acid (EPA) or arachidonic acid (AA) affects the risk of cancer remains unclear, and the association between the serum EPA:AA ratio and cancer risk has not been fully evaluated in general populations.

    Methods: A total of 3098 community-dwelling subjects aged ≥40 years were followed up for 9.6 years (2002–2012). The levels of the serum EPA:AA ratio were categorized into quartiles (<0.29, 0.29–0.41, 0.42–0.60, and >0.60). The risk estimates were computed using a Cox proportional hazards model. The same analyses were conducted for the serum docosahexaenoic acid to arachidonic acid (DHA:AA) ratio and individual fatty acid concentrations.

    Results: During the follow-up period, 121 subjects died of cancer. Age- and sex-adjusted cancer mortality increased with lower serum EPA:AA ratio levels (P trend<0.05). In the multivariable-adjusted analysis, the subjects in the first quartile of the serum EPA:AA ratio had a 1.93-fold (95% confidence interval, 1.15–3.22) greater risk of cancer death than those in the fourth quartile. Lower serum EPA concentrations were marginally associated with higher cancer mortality (P trend<0.11), but the serum DHA or AA concentrations and the serum DHA:AA ratio were not (all P trend>0.37). With regard to site-specific cancers, lower serum EPA:AA ratio was associated with a higher risk of death from liver cancer. However, no such associations were detected for deaths from other cancers.

    Conclusions: These findings suggest that decreased level of the serum EPA:AA ratio is a significant risk factor for cancer death in the general Japanese population.

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  • Huichu Li, Hongjian Bai, Changyuan Yang, Renjie Chen, Cuicui Wang, Zhu ...
    2017 Volume 27 Issue 12 Pages 584-589
    Published: 2017
    Released on J-STAGE: October 12, 2017

    Background: Epidemiological studies have shown the associations of ambient temperature and particulate matter (PM) air pollution with respiratory morbidity and mortality. However, the underlying mechanisms have not been well characterized. The aim of this study is to investigate the associations of temperature and fine and coarse PM with fractional exhaled nitric oxide (FeNO), a well-established biomarker of respiratory inflammation.

    Methods: We conducted a longitudinal panel study involving six repeated FeNO tests among 33 type 2 diabetes mellitus patients from April to June 2013 in Shanghai, China. Hourly temperature and PM concentrations were obtained from a nearby fixed-site monitoring station. We then explored the associations between temperature, PM, and FeNO using linear mixed-effect models incorporated with distributed lag nonlinear models for the lagged and nonlinear associations. The interactions between temperature and PM were evaluated using stratification analyses.

    Results: We found that both low and high temperature, as well as increased fine and coarse PM, were significantly associated with FeNO. The cumulative relative risk of FeNO was 1.75% (95% confidence interval [CI], 1.04–2.94) comparing 15 °C to the referent temperature (24 °C) over lags 0–9 days. A 10 μg/m3 increase in fine and coarse PM concentrations were associated with 1.18% (95% CI, 0.18–2.20) and 1.85% (95% CI, 0.62–3.09) FeNO in lag 0–1 days, respectively. PM had stronger effects on cool days than on warm days.

    Conclusions: This study suggested low ambient temperature, fine PM, and coarse PM might elevate the levels of respiratory inflammation. Our findings may help understand the epidemiological evidence linking temperature, particulate air pollution, and respiratory health.

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Statistical data
  • Chihiro Nishiura, Akiko Nanri, Ikuko Kashino, Ai Hori, Chihiro Kinugaw ...
    2017 Volume 27 Issue 12 Pages 590-595
    Published: 2017
    Released on J-STAGE: October 12, 2017

    Background: Long-term sick-leave is a major public health problem, but data on its incidence in Japan are scarce. We aimed to present reference data for long-term sick-leave among private sector employees in Japan.

    Methods: The study population comprised employees of 12 companies that participated in the Japan Epidemiology Collaboration on Occupational Health Study. Details on medically certified sick-leave lasting ≥30 days were collected from each company. Age- and sex-specific incidence rate of sick-leave was calculated for the period of April 2012 to March 2014.

    Results: A total of 1422 spells in men and 289 in women occurred during 162,989 and 30,645 person-years of observation, respectively. The three leading causes of sick-leave (percentage of total spells) were mental disorders (52%), neoplasms (12%), and injury (8%) for men; and mental disorders (35%), neoplasms (20%), and pregnancy-related disease (14%) for women. Incidence rate of sick-leave due to mental disorders was relatively high among men in their 20s–40s but tended to decrease with age among women. Incidence rate of sick-leave due to neoplasms started to increase after age 50 in men and after age 40 in women, making neoplasms the leading cause of sick-leave after age 50 for women and after age 60 for men and the second leading cause after age 40 for women and after age 50 for men. Pregnancy-related disease was the second leading cause of sick-leave among women aged 20–39 years.

    Conclusions: These results suggest that mental disorder, neoplasms, and pregnancy-related disease are the major causes of long-term sick-leave among private sector employees in Japan.

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