Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 31, Issue 5
Displaying 1-9 of 9 articles from this issue
Original Article
  • Yudai Tamada, Kenji Takeuchi, Chikae Yamaguchi, Masashige Saito, Tetsu ...
    2021 Volume 31 Issue 5 Pages 301-307
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: May 16, 2020

    Background: While laughter is broadly recognized as a good medicine, a potential preventive effect of laughter on disability and death is still being debated. Accordingly, we investigated the association between the frequency of laughter and onset of functional disability and all-cause mortality among the older adults in Japan.

    Methods: The data for a 3-year follow-up cohort including 14,233 individuals (50.3% men) aged ≥65 years who could independently perform the activities of daily living and participated in the Japan Gerontological Evaluation Study were analyzed. The participants were classified into four categories according to their frequency of laughter (almost every day, 1–5 days/week, 1–3 days/month, and never or almost never). We estimated the risks of functional disability and all-cause mortality in each category using a Cox proportional hazards model.

    Results: During follow-up, 605 (4.3%) individuals developed functional disability, identified by new certification for the requirement of Long-Term Care Insurance, and 659 (4.6%) deaths were noted. After adjusting for the potential confounders, the multivariate-adjusted hazard ratio of functional disability increased with a decrease in the frequency of laughter (P for trend = 0.04). The risk of functional disability was 1.42 times higher for individuals who laughed never or almost never than for those who laughed almost every day. No such association was observed with the risk of all-cause mortality (P for trend = 0.39).

    Conclusions: Low frequency of laughter is associated with increased risks of functional disability. Laughter may be an early predictor of functional disability later on in life.

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  • Takashi Oshio
    2021 Volume 31 Issue 5 Pages 308-314
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: May 23, 2020

    Background: The “retired husband syndrome” refers to the negative impact of the husband’s retirement on the wife’s health. This study provided new insights by examining whether and to what extent the wife’s social participation, interactions with her husband, and job status prior to her husband’s retirement affected the evolution of her mental health after her husband’s retirement.

    Methods: We collected data from a 12-wave nationwide panel survey conducted from 2005 to 2016, starting with individuals aged 50–59 years. Focusing on 3,794 female respondents whose husbands retired during the survey period, we applied random-effects linear regression models to investigate the evolution of their mental health as measured by the Kessler 6 (K6) score (range, 0–24; Mean, 3.41; standard deviation, 4.11) during the 5 years after their husbands’ retirement.

    Results: On average, the wife’s K6 score rose by 0.18 (95% confidence interval [CI], 0.08–0.28), 0.18 (95% CI, 0.03–0.34), and 0.19 (95% CI, −0.02 to 0.43) in the first 3 years, respectively, after the husband’s retirement, before declining toward the baseline level. However, the wife’s active social participation, intense interactions with her husband, and absence of paid employment before her husband’s retirement prevented her mental health from deteriorating.

    Conclusion: The results suggest the limited relevance of the “retired husband syndrome” among middle-aged Japanese couples. The effects of a husband’s retirement on the wife’s mental health depended heavily on her prior behavior.

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  • Yoshimune Hiratsuka, Tetsuji Yokoyama, Masakazu Yamada
    2021 Volume 31 Issue 5 Pages 315-319
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: May 30, 2020

    Background: Improving the specific health checkups participation rate is an essential task nationwide; however, studies on measures to accomplish this are limited. This study aimed to examine the influence of ophthalmic checkups on the specific health checkups’ participation rate.

    Methods: We conducted a postal questionnaire survey on 1,741 countrywide municipalities in Japan from January to February 2019. The questionnaire specifically addressed health checkup participation rates of 2017, health checkups formats (group, individual, or both), simultaneous cancer screenings, simultaneous ophthalmic checkups, and the state of implementation of ophthalmic checkups. We used multiple linear regression analyses to calculate the partial regression coefficients (βs) and their 95% confidential intervals (CIs) to identify the influence of simultaneous ophthalmic checkups on specific health checkup participation rates.

    Results: There was a significant association between specific health checkup participation rates and simultaneous ophthalmic checkups (β: +2.5%; 95% CI, 1.3–3.8) after adjusting for covariates. The fundus photos of all applicants, fundus photos with restrictions, and ophthalmology consultation for all applicants were associated with a significant increase in the specific health checkup participation rate (β: +2.8%, 95% CI, 1.2–4.4; β: +2.0%, 95% CI, 0.2–3.9; β: +7.4%, 95% CI, 1.2–13.6 respectively).

    Conclusions: Our results suggest that additional simultaneous ophthalmic checkups as specific health checkups could increase the specific health checkup participation rate.

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  • Kimitaka Nakamura, Daigo Yoshida, Takanori Honda, Jun Hata, Mao Shibat ...
    2021 Volume 31 Issue 5 Pages 320-327
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 06, 2020
    Supplementary material

    Background: The prevalence of sarcopenia defined using the Asian Working Group for Sarcopenia (AWGS) criteria in Asian communities has not been fully addressed. Moreover, few studies have addressed the influence of sarcopenia on mortality.

    Methods: A total of 1,371 and 1,597 residents aged 65 years or older participated in health surveys in 2012 and 2017. Sarcopenia was determined using the AWGS definition. Factors associated with the presence of sarcopenia were assessed using a logistic regression model in participants in the 2012 survey. Subjects in the 2012 survey were followed-up prospectively for a median of 4.3 years. Mortality risk for subjects with sarcopenia was examined using the Cox proportional hazards model.

    Results: The crude prevalence of sarcopenia was 7.4% and 6.6% in participants at the 2012 and 2017 surveys, respectively; there was no significant difference between surveys (P = 0.44). The prevalence of sarcopenia increased significantly with age in both sexes (both P for trend <0.001). Subjects with sarcopenia were more likely to exercise less regularly, to intake less total energy, and to exhibit a disability in activity of daily living than those without. The multivariable-adjusted hazard ratio for all-cause mortality was 2.20 (95% confidence interval, 1.25–3.85) in subjects with sarcopenia, compared to those without.

    Conclusions: Approximately 7% of older subjects had sarcopenia in a community-dwelling older Japanese population. Moreover, subjects with sarcopenia had an increased mortality risk. Our findings suggest that a public health strategy for sarcopenia is needed to extend healthy life expectancy.

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  • Shuko Takahashi, Yuki Yonekura, Kozo Tanno, Haruki Shimoda, Kiyomi Sak ...
    2021 Volume 31 Issue 5 Pages 328-334
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 13, 2020
    Supplementary material

    Background: Previous studies have linked residential displacement as a result of the 2011 East Japan Earthquake to increases in body weight. However, no study has examined longer-term trajectories of body weight among displaced survivors. We compared body weight change between survivors relocated to temporary housing (TH) group versus other types of accommodation for up to 5 years after the Great East Japan Earthquake.

    Methods: Longitudinal follow-up was conducted from 2011 to 2015 in a cohort of 9,909 residents of 42,831. We compared trends in body weight in the TH group (n = 3,169) and the non-TH group (n = 6,740) using a mixed linear regression model stratified by sex (mean age, 61.0 years old; male, 38.9%).

    Results: In age-adjusted analysis, the body weight in the 2011 survey was not significantly different between two groups for either sex. In men, the TH group significantly increased body weight compared to the non-TH group since 2012. In women, body weight sharply increased in the TH group while body weight did not change in the non-TH group during survey time points. The interaction of living conditions and survey years was statistically significant in both sexes (men; F-value, 6.958; P < 0.001: women; F-value, 19.127; P < 0.001).

    Conclusion: Survivors relocated to temporary housing had an increased risk of weight gain. The weight gain in this group is a potential risk factor for metabolic syndrome in the post-disaster period.

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  • Saeideh Fallah-Fini, Nayu Ikeda, Nobuo Nishi
    2021 Volume 31 Issue 5 Pages 335-342
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 27, 2020

    Background: The double burden of malnutrition is a growing public health problem in Japan. We estimated the dynamics of the energy imbalance gap (EIG) (average daily difference between energy intake and expenditure) to explain trends in the prevalence of underweight, overweight, and obese Japanese adults.

    Methods: We used individual-level data on body height and weight from the National Health and Nutrition Surveys from 1975 to 2015. We calibrated a validated system dynamics model to estimate the EIG for Japanese adults aged 20 to 74 years by survey year, sex, and weight status classified by the body mass index (BMI).

    Results: The overall EIG for men increased from 2.3 kcal/day in 1975 to 4.7 kcal/day in 1987 and then decreased to 2.3 kcal/day in 2015. The overall EIG for women consistently decreased from 4.3 kcal/day in 1975 to −0.5 kcal/day in 2015. By BMI class, the EIG for men with a BMI of <30 kg/m2 began to decrease around 1990, indicating a deceleration in the prevalence of overweight and obese men. The EIG consistently decreased for women with a BMI of <25 kg/m2 and reached negative values from the late 2000s to early 2010s, indicating a gradual decrease in the prevalence of overweight and obese women.

    Conclusions: The dynamics of the EIG were different across sex and weight groups. Public health interventions should target a further decrease in the EIG for normal-weight, overweight, and obese men and a stop in the decreasing trends of the EIG in underweight and normal-weight women.

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  • Wen-Chi Pan, Szu-Yu Yeh, Chih-Da Wu, Yen-Tsung Huang, Yu-Cheng Chen, C ...
    2021 Volume 31 Issue 5 Pages 343-349
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 20, 2020
    Supplementary material

    Background: Exposure to traffic-related pollution is positively associated with cardiovascular diseases (CVD), but little is known about how different sources of traffic pollution (eg, gasoline-powered cars, diesel-engine vehicles) contribute to CVD. Therefore, we evaluated the association between exposure to different types of engine exhaust and CVD mortality.

    Methods: We recruited 12,098 participants from REVEAL-HBV cohort in Taiwan. The CVD mortality in 2000–2014 was ascertained by the Taiwan Death Certificates. Traffic pollution sources (2005–2013) were based on information provided by the Directorate General of Highway in 2005. Exposure to PM2.5 was based on a land-use regression model. We applied Cox proportional hazard models to assess the association of traffic vehicle exposure and CVD mortality. A causal mediation analysis was applied to evaluate the mediation effect of PM2.5 on the relationship between traffic and CVD mortality.

    Results: A total of 382 CVD mortalities were identified from 2000 to 2014. We found participants exposed to higher volumes of small car and truck exhausts had an increased CVD mortality. The adjusted hazard ratio (HR) was 1.10 for small cars (95% confidence interval [CI], 0.94–1.27; P-value = 0.23) and 1.24 for truck (95% CI, 1.03–1.51; P-value = 0.03) per one unit increment of the logarithm scale. The findings were still robust with further adjustment for different types of vehicles. A causal mediation analysis revealed PM2.5 had an over 60% mediation effect on traffic-CVD association.

    Conclusions: Exposure to exhaust from trucks or gasoline-powered cars is positively associated with CVD mortality, and air pollution may play a role in this association.

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  • Shiho Amagasa, Noritoshi Fukushima, Hiroyuki Kikuchi, Koichiro Oka, Se ...
    2021 Volume 31 Issue 5 Pages 350-355
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 13, 2020

    Background: Daily step count is the simplest measure of physical activity. However, little is known about how daily step count related to time spent in different intensities of physical activity (PA) and sedentary behavior (SB).

    Methods: These cross-sectional data were derived from 450 older Japanese adults (56.7% men; mean age, 74.3 years) who were randomly selected from three communities and responded a survey. Daily step count and time spent in moderate-to-vigorous PA (MVPA), light-intensity PA (LPA), and SB were measured using a validated wearable technology (HJA-350IT). Associations of daily step count with time spent in measured behaviors were examined using linear regression models with isometric log-ratio transformations of time-use composition, adjusting for gender, age, and residential area.

    Results: Participants averaged 5,412 (standard deviation, 2,878) steps/d and accumulated MVPA, LPA, and SB corresponding to 4.0%, 34.8%, and 61.2% of daily waking time, respectively. Daily step count significantly increased with increase in time spent in MVPA relative to other behaviors (ie, LPA and SB) and in the ratio of LPA to SB after allowing for MVPA. After stratification, daily step count was significantly related to the ratio of LPA to SB in those taking <5,000 steps/d, but not in those taking 5,000–7,499 and ≥7,500 steps/d.

    Conclusions: Higher daily step count can be an indicator of not only larger relative contribution of time spent in MVPA, but also higher ratio between LPA and SB, particularly among those who are the least physically active.

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Short Communication
  • Yuta Taniguchi, Masao Iwagami, Nobuo Sakata, Taeko Watanabe, Kazuhiro ...
    2021 Volume 31 Issue 5 Pages 356-360
    Published: May 05, 2021
    Released on J-STAGE: May 05, 2021
    Advance online publication: June 13, 2020

    Background: With increasing age globally, more people may become vulnerable to food choking. We investigated the nationwide epidemiology of food choking deaths in Japan.

    Methods: Using Japanese Vital Statistics death data between 2006 and 2016, we identified food choking deaths based on the 10th revision of the International Statistical Classification of Diseases code W79 (Inhalation and ingestion of food causing obstruction of respiratory tract) as a primary diagnosis. We assessed the demographics of people with food choking deaths; temporal trends of food choking deaths by the year (overall and by age group), the day of year; and prefecture variations.

    Results: Overall, 52,366 people experienced food choking deaths (median age, 82 years, 53% were male, and 57% occurred at home). The highest numbers occurred January 1–3, and were lowest in June. Despite a stable total number of cases at around 4,000 yearly, from 2006 to 2016 the incidence proportion declined from 16.2 to 12.1 per 100,000 population among people aged 75–84 years. Among people ≥85 years, the incidence proportion peaked at 53.5 in 2008 and decreased to 43.6 in 2016. The number of food choking deaths varied by prefecture.

    Conclusions: There are temporal and regional variations of food choking deaths in Japan, possibly due to the consumption of Japanese rice cake (mochi), particularly over the New Year’s holiday.

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