Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 31 , Issue 3
Showing 1-11 articles out of 11 articles from the selected issue
Original Article
  • Fuyu Miyake, Chimed-Ochir Odgerel, Yuko Mine, Tatsuhiko Kubo, Toshihar ...
    2021 Volume 31 Issue 3 Pages 165-171
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: March 07, 2020
    JOURNALS OPEN ACCESS

    Background: Customarily, bedrooms in Japan are left unheated. Although several studies have reported that the use of a heating system has positive outcomes on respiratory infection and asthma, the preventive effect of heating systems against infectious diseases in children is not well known.

    Methods: We conducted a cohort study using two questionnaire surveys, one before the winter season in November, 2018 and the second after winter in March, 2019. Participants were 155 children who did not use a heating system in the bedroom and 156 children who did.

    Results: Having a heated bedroom with a heating system was associated with decreased odds for the frequency of cold (≥3 times) (adjust odds ratio [AOR] 0.35; 95% confidence interval [CI], 0.19–0.65), duration of fever (≥3 days) (AOR 0.38; 95% CI, 0.22–0.66), duration of medicine for a cold (≥3 days) (AOR 0.91; 95% CI, 0.87–0.95), hospital visit due to cold (≥3 days) (AOR 0.54; 95% CI, 0.31–0.94), absence from school or nursery (≥3 days) (AOR 0.43; 95% CI, 0.27–0.70), influenza infection (AOR 0.43; 95% CI, 0.26–0.71), and gastroenteritis (AOR 0.39; 95% CI, 0.21–0.72). Influenza vaccination reduced the odds of influenza infection (AOR 0.36; 95% CI, 0.22–0.59) and absence from school or nursery (≥3 days) (AOR 0.62; 95% CI, 0.39–0.99).

    Conclusion: This study implies that the heating of bedrooms may have a preventive effect against infections among children. Broader dissemination of this knowledge in Japan will require cultural change through public health awareness.

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  • Madoka Iwase, Keitaro Matsuo, Masahiro Nakatochi, Isao Oze, Hidemi Ito ...
    2021 Volume 31 Issue 3 Pages 172-179
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: March 07, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: Obesity is a reported risk factor for various health problems. Genome-wide association studies (GWASs) have identified numerous independent loci associated with body mass index (BMI). However, most of these have been focused on Europeans, and little evidence is available on the genetic effects across the life course of other ethnicities.

    Methods: We conducted a cross-sectional study to examine the associations of 282 GWAS-identified single nucleotide polymorphisms with three BMI-related traits, current BMI, BMI at 20 years old (BMI at 20), and change in BMI (BMI change), among 11,586 Japanese individuals enrolled in the Japan Multi-Institutional Collaborative Cohort study. Associations were examined using multivariable linear regression models.

    Results: We found a significant association (P < 0.05/282 = 1.77 × 10−4) between BMI and 11 polymorphisms in or near FTO, BDNF, TMEM18, HS6ST3, and BORCS7. The trend was similar between current BMI and BMI change, but differed from that of the BMI at 20. Among the significant variants, those on FTO were associated with all BMI traits, whereas those on TMEM18 and HS6SR3 were only associated with BMI at 20. The association of FTO loci with BMI remained, even after additional adjustment for dietary energy intake.

    Conclusions: Previously reported BMI-associated loci discovered in Europeans were also identified in the Japanese population. Additionally, our results suggest that the effects of each loci on BMI may vary across the life course and that this variation may be caused by the differential effects of individual genes on BMI via different pathways.

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  • Ying-Li Liu, Ying-Jun Mi, Bing Zhang, Hui-Jun Wang, Jie Yu, Xing-Bing ...
    2021 Volume 31 Issue 3 Pages 180-186
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: March 28, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: The diagnosis of hypertension should be based on the mean of two or more properly measured BP readings on each of two visits for clinical practice, but a one-visit strategy was applied in most epidemiological surveys. The impact of hypertension definition based on two visits on estimates of hypertension burden is unknown. This study aims to assess the impact of hypertension diagnosis based on a two-visit strategy for estimating hypertension burden in China.

    Methods: The one-visit and two-visit strategies were applied to investigate the incidence of hypertension in a cohort study based on the China Health and Nutrition Survey (CHNS) 1989–2011. Additionally the prevalence of hypertension was investigated in a cross-sectional study based on the CHNS 2006–2009/2011 and the hypertension burden in China was estimated with data from the 2012–2015 China hypertension survey.

    Results: Overall, the age-adjusted incidence of hypertension based on the two-visit strategy (1.82%; 95% confidence interval [CI], 1.74–1.90%) was 62.1% lower than estimation based on the one-visit strategy (4.80%; 95% CI, 4.68–4.93%). Similar results were found in the prevalence of hypertension (one-visit: 18.13% [95% CI, 17.34–18.92%]; two-visit: 9.47% [95% CI, 8.87–10.07%]). When the two-visit strategy was applied to the 2012–2015 China hypertension survey, the hypertension burden was predicted to be overestimated by 25.5–47.8% (based on JNC 7) and 23.5–48.2% (based on the 2017 ACC/AHA).

    Conclusion: The hypertension burden would decrease from 244.5 million persons to 127.5–182.3 million persons in China if the two-visit strategy was applied.

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  • Ayaka Igarashi, Jun Aida, Taro Kusama, Takahiro Tabuchi, Toru Tsuboya, ...
    2021 Volume 31 Issue 3 Pages 187-193
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: March 28, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: The trend of the diffusion of heated tobacco products (HTPs) is a great concern because HTPs have become available worldwide. This study examined the sociodemographic characteristics of HTPs users in Japan, where HTPs were first launched.

    Methods: This cross-sectional study used data from an online survey conducted in 2017. A total of 4,926 participants, aged 20–69 years, were included. The dependent variable was the type of tobacco products used. The independent variables were age and equivalent income. Two analyses estimated the odds ratios (ORs) for 1) being smokers compared to “non-smokers,” and 2) being “HTP smokers” compared to “only combustible cigarette smokers.” Analyses were stratified by sex. Educational attainment and occupation were also used in the sensitivity analyses.

    Results: The percentages of “non-smokers,” “only combustible cigarette smokers,” and “HTP smokers” were 82.8%, 14.2%, and 3.0%, respectively. When compared to the oldest participants (aged 60–69), the youngest participants (aged 20–29) tended to be “HTP smokers” (OR 7.90; 95% confidence interval [CI], 3.09–20.22 for men and OR 9.28; 95% CI, 2.14–40.28 for women). Compared to participants with the lowest incomes (<2 million), those with the highest incomes (≥4 million) tended to use HTPs (OR 2.93; 95% CI, 1.56–5.49 in men and OR 1.82; 95% CI, 0.73–4.54 in women). These trends were consistent when analyses included only smokers. There were consistent results in other SES measurements, including educational attainment and occupation.

    Conclusions: Younger or more affluent people tended to use HTPs, although smoking rates among these populations were generally lower. New tobacco control efforts are required.

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  • Noritoshi Fukushima, Takafumi Abe, Jun Kitayuguchi, Chiaki Tanaka, Shi ...
    2021 Volume 31 Issue 3 Pages 194-202
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: March 28, 2020
    JOURNALS OPEN ACCESS

    Background: Physical activity (PA) guidelines for early childhood have been established worldwide, and adherence to PA guidelines has been utilized to assess the effectiveness of policies regarding PA promotion. Although there is a Japanese PA guideline for preschoolers, little is known about adherence to this recommendation. This study examined and compared proportions of meeting the Japanese PA guideline among preschoolers.

    Methods: Participants comprised 821 children aged 3–6 years from all 21 preschools and childcare facilities (hereafter collectively “preschools”) within Unnan City, Shimane Prefecture, Japan. Data on PA levels were collected through a parent-report questionnaire in accordance with the Japanese PA guideline. This guideline recommends that preschoolers perform PA for at least 60 minutes every day. Analyses included descriptive statistics, chi-squared, and Mann–Whitney’s tests to compare adherence to the PA guideline.

    Results: Data of 441 participants from 20 preschools were analyzed. Of these, 292 (66.2%) preschoolers met the PA guideline. Boys (70.2%) showed a significantly higher proportion of meeting the PA guideline than girls (61.2%; P = 0.048). Proportions of meeting the PA guideline among preschool grades were not statistically different. Prevalence rates of meeting the PA guideline among 20 preschools considerably varied from 14.3% to 100% (P = 0.007).

    Conclusions: Two-thirds of preschoolers met the Japanese PA guideline, while adherence to PA recommendations differed between genders. Moreover, there were distinct variations of adherence to PA guideline among preschools. Possible determinants that cause the differences in adherence to the PA guideline at the individual and preschool-levels should be further evaluated.

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  • Takashi Oshio
    2021 Volume 31 Issue 3 Pages 203-209
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: April 04, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: Precarious job status is negatively related with workers’ health. Research has yet to address whether and to what extent the area-level risk of precarious employment is associated with workers’ health, independently from their job status. We addressed this issue in the present study.

    Methods: We estimated multi-level logistic regression models using repeated cross-sectional data comprising 253,048 men and 210,761 women aged 20–59 years who were living in 47 prefectures. This data were obtained from population-based surveys conducted in 2010, 2013, and 2016 in Japan.

    Results: For male workers, the estimated odds of reporting poor self-rated health, subjective symptoms, and problems in activities of daily living for those residing in the prefectures in the highest tertile of the proportion of precarious employees were 1.10 (95% confidence interval [CI], 1.01–1.18), 1.12 (95% CI, 1.05–1.19), and 1.15 (95% CI, 1.04–1.28) times, respectively, higher than those living in the prefectures in the lowest tertile, even after controlling for individuals’ job status and key covariates. The results remained largely similar, despite focusing on the sample with information about household income, which was available from the survey, and controlling for it. In contrast, the results indicated that women’s health outcomes were not associated with the prefecture-level proportion of precarious employees.

    Conclusions: The area-level risk of precarious employment matters for male workers’ health independently from their job status, underscoring the importance of policy measures aimed to reduce the adverse impacts of precarious employment on workers’ health.

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  • Jing Sun, Zhaoying Li, Yan Li, Dongfeng Zhang
    2021 Volume 31 Issue 3 Pages 210-219
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: April 11, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: Epidemiological evidence on the relationships between intakes of different categories of vegetables and fruits and depressive symptoms is very limited and inconsistent, especially with no evidence from the general population. This study aimed to estimate their relationships among a large general population.

    Methods: The cross-sectional design was based on the National Health and Nutrition Examination Survey (2007–2014) and included 16,925 adults. Dietary information was attained from two nonconsecutive 24-hr dietary recalls. Patient Health Questionnaire was applied for measuring depressive symptoms. The associations between vegetables and fruits intakes and depressive symptoms were appraised utilizing logistic regression and restricted cubic spline.

    Results: Compared with the lowest category of intake, the most-adjusted odds ratios of depressive symptoms for the highest intake category of tomatoes and tomato mixtures were 0.81 (95% confidence interval [CI], 0.66–0.99), and 0.64 (95% CI, 0.48–0.85) for dark-green vegetables, 0.67 (95% CI, 0.53–0.84) for other vegetables, 0.48 (95% CI, 0.29–0.79) for berries, 0.67 (95% CI, 0.55–0.82) for total vegetables, and 0.70 (95% CI, 0.57–0.86) for total fruits, and for the medium categories of bananas and dried fruits were 0.62 (95% CI, 0.41–0.95) and 0.39 (95% CI, 0.19–0.81), respectively. After sensitivity analysis further excluding subjects with co-morbid health conditions, these findings remained significant, except for bananas. An L-shaped relationship was observed between depressive symptoms and intake of total vegetables, while the association was linear with total fruits intake.

    Conclusions: Intakes of tomatoes and tomato mixtures, dark-green vegetables, other vegetables, berries, dried fruits, total vegetables, and total fruits were inversely related to depressive symptoms among adults.

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Review Article
  • Xiuting Mo, Ruoyan Gai Tobe, Yoshimitsu Takahashi, Naoko Arata, Tippaw ...
    2021 Volume 31 Issue 3 Pages 220-230
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: May 23, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: This study aims to find evidence of the cost-effectiveness of gestational diabetes mellitus (GDM) screening and assess the quality of current economic evaluations, which have shown different conclusions with a variation in screening methods, data sources, outcome indicators, and implementation in diverse organizational contexts.

    Methods: Embase, Medline, Web of Science, Health Technology Assessment, database, and National Health Service Economic Evaluation Database databases were searched through June 2019. Studies on economic evaluation reporting both cost and health outcomes of GDM screening programs in English language were selected, and the quality of the studies was assessed using Drummond’s checklist. The general characteristics, main assumptions, and results of the economic evaluations were summarized.

    Results: Our search yielded 10 eligible economic evaluations with different screening strategies compared in different settings and perspectives. The selected papers scored 81% (68–97%) on the items in Drummond’s checklist on average. In general, a screening program is cost-effective or even dominant over no screening. The one-step screening, with more cases detected, is more likely to be cost-effective than the two-step screening. Universal screening is more likely to be cost-effective than screening targeting the high-risk population. Parameters affecting cost-effectiveness include: diagnosis criteria, epidemiological characteristics of the population, efficacy of screening and treatment, and costs.

    Conclusions: Most studies found GDM screening to be cost-effective, though uncertainties remain due to many factors. The quality assessment identified weaknesses in the economic evaluations in terms of integrating existing data, measuring costs and consequences, analyzing perspectives, and adjusting for uncertainties.

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Statistical Data
  • Hiroyuki Ohbe, Tadahiro Goto, Ryuichi Yamazaki, Taisuke Jo, Hiroki Mat ...
    2021 Volume 31 Issue 3 Pages 231-236
    Published: March 05, 2021
    Released: March 05, 2021
    [Advance publication] Released: April 04, 2020
    JOURNALS OPEN ACCESS

    Background: For patients with suicide attempts or self-harm, acute-care hospitals often function as the primary or sole point of contact with the healthcare system. However, little is known about patient characteristics or clinical trajectories of suicide attempts and self-harm episodes among those admitted to acute-care hospitals. This study aimed to describe the characteristics of suicide attempts and self-harm among patients admitted to acute-care hospitals, and the clinical practices provided in these hospitals, using a nationwide inpatient database in Japan.

    Methods: Using data from the Japanese Diagnosis Procedure Combination inpatient database from June 2015 to March 2017, we identified patients with emergency admission for suicide attempts or self-harm. We did not include patients with elective admission to psychiatric hospitals or outpatients. We described patient characteristics, treatments for physical injuries, psychiatric interventions, and discharge status.

    Results: We identified 17,881 eligible patients during the 22-month study period. Overall, 38% of the patients did not have any psychiatric or behavioral comorbidities at admission. The most common suicide method was drug overdose (50%), followed by hanging (18%), jumping from a height (13%), cutting or piercing without wrist cutting (7.1%), poisoning (6.6%), and wrist cutting (5.4%). Suicide was completed by 2,639 (15%) patients. Among patients discharged to home, 51% did not receive any psychiatric intervention. In 468 acute-care hospitals (54%), no psychiatric intervention was provided during the study period.

    Conclusion: We found that half of acute-care hospitals did not provide any hospital-based psychiatric care for patients with suicide attempts or self-harm.

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Letter to the Editor
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