Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 33, Issue 7
Displaying 1-8 of 8 articles from this issue
Original Article
  • Masaaki Yamada, Michikazu Sekine, Takashi Tatsuse
    2023 Volume 33 Issue 7 Pages 335-341
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: November 06, 2021

    Background: Pathological gaming (PG) has emerged as one of the major public health concerns worldwide. We aimed to assess PG and its associated factors among elementary school children in Japan.

    Methods: We conducted a school-based observational study in Toyama, Japan in 2018. In total, 13,413 children in the 4th–6th grades (mean age, 10.5 years) participated in the study. We distributed questionnaires and inquired about their lifestyle, irritability, and school and family environments. Referring to criteria of gaming disorder in the International Statistical Classification of Disease (ICD-11), we asked about three core symptoms: impaired control over gaming, increasing priority given to gaming over other activities, and continuation of gaming despite the negative consequences. Children who had all three criteria in the questionnaire were defined as PG.

    Results: The response rate was 97.6%, and 11,826 children were included in our analyses (88.2%). The prevalence of PG was 5.6% (7.8% in boys, 3.2% in girls). Besides sex, PG was significantly associated with lifestyles, including skipping breakfast (odds ratio [OR] 1.33; 95% confidence interval [CI], 1.05–1.68), physical inactivity (OR 2.23; 95% CI, 1.63–3.05 for rare), late bed time (OR 2.52; 95% CI, 1.96–3.25 for ≥11 p.m.), frequent irritability (OR 1.89; 95% CI, 1.47–2.43), frequent feeling of school avoidance (OR 1.92; 95% CI, 1.49–2.46), fewer close friends (OR 1.30; 95% CI, 1.08–1.56 for some), low academic performance (OR 1.53; 95% CI, 1.13–2.08), no child–parent interaction (OR 1.34; 95% CI, 1.02–1.75), and no rules at home (OR 1.21; 95% CI, 1.02–1.43).

    Conclusion: Unhealthy lifestyles, irritability, and low functioning in school and family environments were associated with PG. Besides having a healthy lifestyle, parental involvement appears to be an indispensable countermeasure for PG in children.

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  • Thomas Svensson, Norie Sawada, Masaru Mimura, Shoko Nozaki, Ryo Shikim ...
    2023 Volume 33 Issue 7 Pages 342-349
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: December 18, 2021
    Supplementary material

    Background: The number of people with cognitive impairment, including dementia, in the world is steadily increasing. Although the consumption of isoflavones and soy is associated with a reduced risk of cardiovascular disease, it might also be associated with cognitive impairment. The low number of studies investigating the association between soy/isoflavone intake and cognitive function warrant additional research.

    Methods: The Japan Public Health Center-based prospective (JPHC) Study is a large population-based cohort. Midlife dietary intake of soy and the isoflavone genistein was assessed on two occasions: in the years 1995 and 2000. In 2014–2015, 1,299 participants from Nagano prefecture completed a mental health screening. Of these, a total of 1,036 participants were included in analyses. Logistic regression was used to determine Odds Ratios (OR) and 95% Confidence Intervals (CI) for the association between midlife energy-adjusted genistein and soy food intake and cognitive impairment.

    Results: There were 392 cases of cognitive impairment (346 cases of MCI and 46 cases of dementia). Compared to the lowest dietary quartile of energy-adjusted genistein intake, the highest quartile was significantly associated with cognitive impairment (OR = 1.51; 95% CI, 1.02–2.24; P for trend = 0.03) in the final multivariable analysis.

    Conclusion: High midlife intake of the isoflavone genistein is associated with late-life cognitive impairment.

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  • Satoshi Seino, Yu Nofuji, Yuri Yokoyama, Takumi Abe, Mariko Nishi, Mar ...
    2023 Volume 33 Issue 7 Pages 350-359
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: December 18, 2021
    Supplementary material

    Background: This 3.6-year prospective study examined combined impacts of physical activity, dietary variety, and social interaction on incident disability and estimated population-attributable fraction for disability reduction in older adults.

    Methods: Participants were 7,822 initially non-disabled residents (3,966 men and 3,856 women) aged 65–84 years of Ota City, Tokyo, Japan. Sufficiency of moderate-to-vigorous-intensity physical activity (MVPA) ≥150 min/week, dietary variety score (DVS) ≥3 (median), and social interaction (face-to-face and/or non-face-to-face) ≥1 time/week was assessed using self-administered questionnaires. Disability incidence was prospectively identified using the long-term care insurance system’s nationally unified database.

    Results: During a follow-up of 3.6 years, 1,046 (13.4%) individuals had disabilities. Independent multivariate-hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA, DVS, and social interaction sufficiency for incident disability were 0.68 (95% CI, 0.59–0.78), 0.87 (95% CI, 0.77–0.99), and 0.90 (95% CI, 0.79–1.03), respectively. Incident disability HRs gradually reduced with increased frequency of satisfying these behaviors (any one: HR 0.82; 95% CI, 0.65–1.03; any two: HR 0.65; 95% CI, 0.52–0.82; and all three behaviors: HR 0.54; 95% CI, 0.43–0.69), in an inverse dose-response manner (P < 0.001 for trend). Population-attributable fraction for disability reduction in satisfying any one, any two, and all three behaviors were 4.0% (95% CI, −0.2 to 7.9%), 9.6% (95% CI, 4.8–14.1%), and 16.0% (95% CI, 8.7–22.8%), respectively.

    Conclusion: Combining physical activity, dietary variety, and social interaction substantially enhances the impacts on preventing disability among older adults, with evidence of an inverse dose-response manner. Improving insufficient behavior elements through individual habits and preexisting social group activities may be effective in preventing disability in the community.

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  • Ehab S. Eshak, Sachiko Baba, Hiroshi Yatsuya, Hiroyasu Iso, Yoshihisa ...
    2023 Volume 33 Issue 7 Pages 360-366
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: February 12, 2022
    Supplementary material

    Background: Total work-family conflicts (TWFCs) could associate with mental health, and having ikigai (a purpose of life) may mediate this association.

    Methods: In a cross-cultural study of 4,792 Japanese Aichi Workers’ Cohort study participants and 3,109 Egyptian civil workers, the Midlife Development in the United States (MIDUS) questionnaire measured TWFCs and the Center for Epidemiological Studies Depression (CES-D) 11-item scale measured depression. We used logistic regression models to estimate odds ratios (ORs) of having depression and a high-ikigai across levels of TWFCs (low, moderate, and high), and the PROCESS macro of Hayes to test the mediation effect.

    Results: The prevalence of high TWFCs, depression, and having a high ikigai were 17.9%, 39.4%, and 70.1% in Japanese women, 10.5%, 26.8%, and 70.1% in Japanese men, 23.7%, 58.2%, and 24.7% in Egyptian women, and 19.1%, 38.9%, and 36.9% in Egyptian men, respectively. Compared with participants with low TWFCs, the multivariable ORs of depression in Japanese women and men with high TWFCs were 4.11 (95% confidence interval [CI], 2.99–5.65) and 5.42 (95% CI, 4.18–7.02), and those in Egyptian women and men were 4.43 (95% CI, 3.30–5.95) and 4.79 (95% CI, 3.53–6.48), respectively. The respective ORs of having a high-ikigai were 0.46 (95% CI, 0.33–0.64) and 0.40 (95% CI, 0.31–0.52) in Japanese women and men and were 0.34 (95% CI, 0.24–0.48) and 0.28 (95% CI, 0.20–0.39) in Egyptian women and men. No interaction between TWFCs and country was observed for the associations with depression or ikigai. Ikigai mediated (up to 18%) the associations between the TWFCs and depression, especially in Egyptian civil workers.

    Conclusion: TWFCs were associated with depression, and having low ikigai mediated these associations in Japanese and Egyptian civil workers.

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Short Communication
  • Silvano Gallus, Cristina Bosetti, Giuseppe Gorini, Chiara Stival, Robe ...
    2023 Volume 33 Issue 7 Pages 367-371
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: February 25, 2023
    Supplementary material

    Background: Despite the robust evidence of an excess risk of coronavirus disease 2019 (COVID-19) severity and mortality in ever smokers, the debate on the role of current and ex-smokers on COVID-19 progression remains open. Limited or no data are available on the link between electronic cigarette (e-cigarette), heated tobacco product (HTP) and second-hand smoke (SHS) exposure and COVID-19 progression. To fill this knowledge gap, we undertook the COvid19 and SMOking in ITaly (COSMO-IT) study.

    Methods: A multi-centre longitudinal study was conducted in 2020–2021 in 24 Italian hospitals on a total of 1,820 laboratory-confirmed COVID-19 patients. We estimated multivariable odds ratios (OR) and 95% confidence intervals (CI) to quantify the association between smoking-related behaviours (ie, smoking status, e-cigarette and HTP use, and SHS exposure) and COVID-19 severity (composite outcome: intubation, intensive care unit admission and death) and mortality.

    Results: Compared to never smokers, current smokers had an increased risk of COVID-19 mortality (OR 2.17; 95% CI, 1.06–4.41). E-cigarette use was non-significantly associated to an increased risk of COVID-19 severity (OR 1.60; 95% CI, 0.96–2.67). An increased risk of mortality was observed for exposure to SHS among non-smokers (OR 1.67; 95% CI, 1.04–2.68), the risk being particularly evident for exposures of ≥6 hours/day (OR 1.99; 95% CI, 1.15–3.44).

    Conclusion: This multicentric study from Italy shows a dismal COVID-19 progression in current smokers and, for the first time, in SHS exposed non-smokers. These data represent an additional reason to strengthen and enforce effective tobacco control measures and to support smokers in quitting.

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Statistical Data
  • Hirokazu Tanaka, Sayo Tanaka, Kayo Togawa, Kota Katanoda
    2023 Volume 33 Issue 7 Pages 372-380
    Published: July 05, 2023
    Released on J-STAGE: July 05, 2023
    Advance online publication: February 11, 2023
    Supplementary material

    Background: The 2015 Japan Standard Population (JSP) was established in response to changes in the age structure. However, the effects of major updates, especially the recategorization of older age groups, for interpreting various health metrics have not been clarified.

    Methods: Population data were collected and estimated for older age categories (85–89, 90–94, and ≥95 years). Data on the number of deaths were also collected from the Vital Statistics. We recalculated the all-cause and leading cause-specific age-standardized mortality rate (ASMR) using the 2015 JSP by the direct standardization method for data from 1950 to 2020. We compared ASMRs calculated using the 2015 JSP with those calculated using the 1985 JSP. Pearson’s correlation coefficients were used to evaluate the consistency of mortality trends between the 2015 and 1985 JSPs.

    Results: The absolute all-cause ASMRs calculated using the 2015 JSP were 2.22–3.00 times higher than those calculated using the 1985 JSP. The ASMR ratios increased gradually over time. While trends in all-cause and cause-specific ASMRs calculated using the 2015 JSP and 1985 JSP were generally highly correlated (Pearson’s correlation coefficient [r] = 0.993 for all-cause), correlations were relatively low for malignant neoplasms (r = 0.720 for men and r = 0.581 for women) and pneumonia/bronchitis (r = 0.543 for men and r = 0.559 for women) due to non-monotonous trends over time and fluctuations in earlier time periods.

    Conclusion: The effect of introducing the new JSP for interpreting trends in all-cause mortality was considered minimal. However, caution is needed when interpreting trends in some cause-specific mortality rates.

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Letter to the Editor