Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 30 , Issue 12
Showing 1-8 articles out of 8 articles from the selected issue
Original Article
  • Xiling Yin, Deyun Li, Kejing Zhu, Xiaodong Liang, Songxu Peng, Aijun T ...
    2020 Volume 30 Issue 12 Pages 529-536
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: November 09, 2019
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: The patterns and risk factors of intentional injuries compared to unintentional injuries among Chinese children and adolescents have not been examined in depth. This work comprehensively describes patterns of intentional injuries in China, for which little information has been previously published.

    Methods: All cases involving individuals 0–17 years old registered at emergency rooms and outpatient clinics were examined using data submitted to the National Injury Surveillance System from 2006 through 2017. A logistic regression model was performed to explore the risk factors related to intentional injuries compared to unintentional injuries.

    Results: A total of 81,459 (95.1%) unintentional injuries, 4,218 (4.9%) intentional injuries (4,013 violent attacks and 205 self-mutilation/suicide) cases were identified. Blunt injuries accounted for 59.4% of violent attacks, while cuts and poisoning accounted for 37.1% and 23.4% of injuries involving self-mutilation/suicide, respectively. For unintentional injuries, falls (50.4%) ranked first. Additional risk factors for intentional injuries included being male (odds ratio [OR] 1.6), coming from rural areas (OR 1.9), being staff or workers (OR 2.2), and being a student (OR 1.8). As the age of the patients increased, so did the risk of intentional injuries (OR 5.0 in the 15–17 age group). Intentional injuries were more likely to occur at 00:00–03:00 am (OR 2.0).

    Conclusions: Intentional injuries affected more males, rural and older children, school students, and staff or workers. The mechanisms and occurrence times differed according to age group. Preventive measures should be taken to reduce the dropout of rural students, strengthen the school’s violence prevention plan, and reduce self-harm.

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  • Nam-Hee Kim, Ichiro Kawachi
    2020 Volume 30 Issue 12 Pages 537-541
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: December 07, 2019
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: In 2009, the South Korean government expanded universal health insurance to include oral health services. In the present study, we sought to examine whether improved access resulted in a reduction in income-based self-reported oral health inequalities.

    Methods: We analyzed repeated cross-sectional data from the Korea National Health and Nutrition Examination Survey (KNHANES) waves IV through VI (2007–2015). We analyzed self-reported oral health status among 68,431 subjects. Changes in oral health inequalities across four income levels (low, middle-low, middle-high, and high) were assessed with the Slope Index of Inequality (SII) and the Relative Index of Inequality (RII).

    Results: The average oral health status of children and adolescents improved the most over the observation period. The absolute magnitude of oral health inequalities (measured by the SII) improved for most groups, with the notable exception of young male adults. By contrast, the ratio of poor oral health between high- and low-income groups (measured by the RII) changed little over time, indicating that relative inequalities remained resistant to change.

    Conclusions: The expansion of dental health insurance may not be sufficient to move the needle on self-reported oral health inequalities among adults.

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  • Shotaro Aso, Hiroki Matsui, Hideo Yasunaga
    2020 Volume 30 Issue 12 Pages 542-546
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: December 07, 2019
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: Computed tomography (CT) is commonly used in children with mild head injuries. People in Japan are concerned about radiation exposure and radiation-induced cancer because of the Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011. This study investigated whether the accident influenced the use of CT in children with mild head injuries.

    Methods: Using the Japan Medical Data Center database, we identified patients aged ≤15 years visiting hospitals because of mild head injuries from January 1, 2008, to December 31, 2013. We excluded patients who were admitted to the hospital or received other medical examinations. Regression discontinuity analysis was used to compare proportions of patients undergoing head CT and having clinically important traumatic brain injury (ciTBI) overlooked before versus after the accident, adjusting for patient characteristics, secular trends, and hospital effect.

    Results: Eligible patients (n = 40,440) were classified as visiting the hospital before (n = 11,659) or after (n = 28,781) the accident. The regression discontinuity analysis showed that the accident was associated with a reduction in the proportion of patients undergoing head CT (odds ratio [OR] 0.73; 95% confidence interval [CI], 0.63–0.86), whereas the accident was not associated with an increase in cases where ciTBI was overlooked (OR 0.72; 95% CI, 0.13–4.00).

    Conclusions: The use of CT in children with mild head injuries declined after the Fukushima Daiichi Nuclear Power Plant accident. Improving awareness of radiation exposure risks among patients and physicians could reduce unnecessary CT.

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  • Aya Kinjo, Yuki Kuwabara, Maya Fujii, Aya Imamoto, Yoneatsu Osaki, Rur ...
    2020 Volume 30 Issue 12 Pages 547-555
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: November 30, 2019
    JOURNALS OPEN ACCESS

    Background: In this study, we aim to estimate the prevalence of heated tobacco product (HTP) smokers 3 years after the launch of HTPs in Japan.

    Methods: Our study, performed in February 2018 in Japan, had a cross-sectional population-based design. A total of 4,628 adult participants (2,121 men and 2,507 women) were randomly sampled from all regions of Japan. The response rate was 57.9%. Interviews were conducted by trained investigators who visited participants’ homes. A survey on current (past 30 days) and lifetime tobacco use (including e-cigarettes and HTPs), as well as numerous sociodemographic factors, was conducted.

    Results: The age-adjusted rates and estimated number of lifetime-HTP smokers were 14.1% (95% confidence interval [CI], 12.5–15.6%; 7.11 million men) and 3.7% (95% CI, 2.9–4.4%; 1.99 million women). The age-adjusted rates for current HTP smokers were 8.3% (95% CI, 7.1–9.6%; 4.21 million men) and 1.9% (95% CI, 1.3–2.4%; 1.02 million women). Multiple variables were found to be associated with a higher prevalence of current HTP use, including being male, aged 20–39 years, a current Internet user, a risky drinker, or a heavy episodic drinker. HTP use was also higher among men with 10 years or more of education, women with 15 years or less of education, and men with middle- or high-level household incomes.

    Conclusion: We concluded that HTP use has increased substantially in Japan. However, regulations for HTPs are weaker than those for combustible cigarettes in Japan. Thus, HTPs should be subjected to the same regulations as combustible tobacco products.

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  • Michiko Furuta, Kenji Takeuchi, Toru Takeshita, Akihiko Tanaka, Shino ...
    2020 Volume 30 Issue 12 Pages 556-565
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: February 01, 2020
    JOURNALS OPEN ACCESS
    Supplementary material

    Background: Toothbrushing is a health-related lifestyle habit and has been reported to contribute not only to oral health but also to some parameters of general health; however, little research has been conducted to understand the association of the frequency and timing of toothbrushing with the development of comprehensive metabolic abnormalities, with consideration of oral health condition. In this study, using longitudinal data, we examined this association in Japanese adults, adjusting for periodontal condition.

    Methods: A 5-year longitudinal study was performed with 4,537 participants between 35 and 64 years old who underwent an annual dental examination in both 2003 and 2008. Data about toothbrushing habits and metabolic abnormalities, such as obesity, hyperglycemia, diabetes, hypertension, hypertriglyceridemia, and low levels of high-density lipoprotein-cholesterol, were analyzed using Poisson regression analysis.

    Results: The percentage of participants with a toothbrushing frequency ≤1 time/day was 29.4%, and that for those not brushing their teeth at night was 21.4%. The incidences of obesity and hyperglycemia after 5 years were 5.5% and 28.4%, respectively. A toothbrushing frequency ≤1 time/day was associated with development of obesity (prevalence rate ratio [PRR] 1.77; 95% confidence interval [CI], 1.12–2.80), after adjusting for periodontal condition and potential risk factors. A significant association between not brushing teeth at night and hyperglycemia (PRR 1.30; 95% CI, 1.02–1.66) was observed in participants with toothbrushing frequency of 1 time/day. No association was found between toothbrushing habits and other metabolic abnormalities.

    Conclusions: This study suggests that toothbrushing habits are associated with the development of obesity and hyperglycemia.

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  • Taiji Noguchi, Hiroko Nakagawa-Senda, Yuya Tamai, Takeshi Nishiyama, M ...
    2020 Volume 30 Issue 12 Pages 566-573
    Published: December 05, 2020
    Released: December 05, 2020
    [Advance publication] Released: December 07, 2019
    JOURNALS OPEN ACCESS

    Background: Second-hand smoke exposure has been associated with poor mental health. However, among Japanese adults, little is known about the association between second-hand smoking and depressive symptoms. We examined this association in a cross-sectional study among a Japanese general adult population sample.

    Methods: Japanese adults were recruited from the Japan Multi-Institutional Collaborative Cohort Study in the Okazaki area between 2012 and 2017. Second-hand smoke exposure and smoking status were assessed using a self-administered questionnaire. Based on their frequency of exposure to second-hand smoke, non-smokers and smokers were categorized as “almost never,” “sometimes,” and “almost every day”. Depressive symptoms were defined by a Kessler 6 score ≥5 points. We performed a multivariable Poisson regression analysis to obtain adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) for depressive symptoms.

    Results: Overall, 5,121 participants (4,547 non-smokers and 574 smokers) were included whose mean age was 63.6 (standard deviation [SD], 10.3) years for non-smokers and 59.33 (SD, 10.2) years for smokers. The association between second-hand smoking and depressive symptoms was significant among non-smokers, but not among smokers. Among non-smokers, PRs compared with “almost never” were 1.25 (95% CI, 1.09–1.42) for “sometimes” and 1.41 (95% CI, 1.09–1.84) for “almost every day” (P for trend <0.001); among smokers, PRs compared with “almost never” were 1.30 (95% CI, 0.82–2.06) for “sometimes” and 1.44 (95% CI, 0.90–2.33) for “almost every day” (P for trend = 0.144).

    Conclusions: Second-hand smoking and depressive symptoms were associated among non-smokers. Our findings indicate the importance of tobacco smoke control for mental health.

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