Background: This study aimed to assess the clinical relevance of three-dimensional occupational stress (job stressor score [A score], psychological and physical stress response score [B score], and social support for workers score [C score]) of the Brief Job Stress Questionnaire (BJSQ) in the national stress check program in Japan to irregular menstruation.

Methods: The present retrospective cohort study included 2,078 female employees aged 19–45 years who had both annual health checkups and the BJSQ between April 2019 and March 2022 in a national university in Japan. The outcome was self-reported irregular menstruation measured at annual health checkups until March 2023. A dose-dependent association between BJSQ scores and incidence of irregular menstruation was examined using Cox proportional hazards models to calculate multivariable-adjusted hazard ratios (HRs) of four quantile (0–49% [Q_0–49], 50–74% [Q_50–74], 75–89% [Q_75–89], and 90–100% [Q_90–100]) of the BJSQ scores.

Results: During 2.0 years of the median observational period, 257 (12.4%) women reported irregular menstruation. B score, not A or C scores, was identified as a significant predictor of irregular menstruation (adjusted HR of A, B, and C scores per 1 standard deviation: 1.06 [95% confidence interval {CI}, 0.89–1.27], 1.35 [95% CI, 1.15–1.57], and 0.93 [95% CI, 0.80–1.08], respectively). Women with higher B score had a significantly higher risk of irregular menstruation in a dose-dependent manner (adjusted HR of Q_0–49, Q_50–74, Q_75–89, and Q_90–100: 1.00 [reference], 1.38 [95% CI, 1.00–1.90], 1.48 [95% CI, 1.00–2.18], and 2.18 [95% CI, 1.38–3.43], respectively).

Conclusion: Psychological and physical stress response predicted irregular menstruation.

Background: We aimed to investigate the association between women’s birth weight and their reproductive characteristics.

Methods: We used data from the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT), a population-based cohort in Japan. The main analysis included 40,796 women aged 40 to 68 years. Outcomes of interest were age at menarche, age at menopause, history of menstrual irregularity, and nulliparity. Associations between self-reported birth weight categories and outcomes were assessed using either a linear regression or a modified Poisson regression adjusted for potential confounders.

Results: Among participants with complete data, those with lower birth weights (<1,500 g and 1,500–2,499 g) compared to women with a birth weight of 3,000–3,999 g had a later age at menarche (adjusted mean difference [aMD]: 2.4 months and 2.0 months, respectively), earlier age at menopause (aMD: −6.7 months and −2.7 months, respectively), and therefore a shorter reproductive span (aMD: −7.7 months and −4.5 months, respectively). They also had a higher risk of menstrual irregularity (adjusted relative risk [aRR]: 1.19 and 1.11, respectively) and a higher likelihood of nulliparity (aRR: 1.25 and 1.19, respectively).

Conclusion: We observed that Japanese women’s birth weight was significantly associated with reproductive characteristics. Specifically, those with a low birth weight had a shorter reproductive span and a higher risk of irregular menses and nulliparity compared to those with a normal birth weight.

Background: Long-term sickness absence (LTSA) is an important public health challenge, yet limited data exist on its incidence in Japan. We aimed to describe the incidence of all-cause and cause-specific LTSA by sex and age using 10-year data from a large Japanese working population, with a focus on sex differences.

Methods: The study participants were employees from 16 worksites in the Japan Epidemiology Collaboration on Occupational Health Study between April 2012 and March 2022. LTSA, defined as sickness absence from work lasting 30 days or more, was recorded at each worksite. The causes of LTSA were classified using the International Classification of Diseases, 10th Revision. Incidence rates for all-cause and cause-specific LTSA were calculated based on sex and age.

Results: During 730,391 and 161,513 person-years of follow-up, 6,518 and 1,866 spells of LTSA were recorded in males and females, respectively. Females had higher incidence rates of all-cause LTSA than males (115.5 vs 89.2 per 10,000 person-years), especially among females in their 20s and 30s. This was partly attributed to younger females experiencing higher LTSA incidence rates due to mental disorders, neoplasms, and pregnancy-related illnesses. In older age, females had higher LTSA incidence rates than males for musculoskeletal diseases and injuries/external causes, whereas LTSA incidence rates due to circulatory diseases were lower than those in males.

Conclusion: The incidence of total and cause-specific LTSA varied greatly by sex and age, highlighting the need to consider employees’ characteristics in the prevention and management of LTSA.

Background: Socioeconomic inequalities in cancer screening participation remain a public health issue worldwide. We assessed trends in cancer screening participation according to socioeconomic status in Japan between 2013 and 2022, considering the potential impact of the coronavirus disease 2019 (COVID-19) pandemic.

Methods: Data from the nationally representative Comprehensive Survey of Living Conditions (2013–2022: approximately 500,000 persons per survey) were analyzed for age-standardized self-reported cancer screening rates for stomach, lung, colon, breast (aged 40–69 years), and cervical (aged 20–69 years) cancers, stratified by education levels. An age-adjusted Poisson model was used to assess the statistical significance of changes between the survey years.

Results: A clear socioeconomic gradient was observed, particularly in stomach cancer screening, where the 2022 rates ranged from 28.3% (low education) to 58.2% (high education) for men and 20.2% to 43.2% for women, depending on education level. Between 2019 and 2022, screening rates for stomach, lung, and colorectal cancers changed by −1.2%, −0.9%, and +0.6% for men and −1.0%, +0.1%, and +1.4% for women, respectively. Breast and cervical cancer screening rates declined by 0.5% and 0.4%, respectively. The COVID-19 pandemic worsened inequalities, with a 3.1% decline in breast cancer screening among individuals with low education level, compared to a 1.0% decline among those with higher education level.

Conclusion: The COVID-19 pandemic had a minor impact on screening rates (counteracting increasing trends of screening rates), except for colorectal cancer screening rates; however, the impact was relatively severe for individuals with lower socioeconomic status, especially for women.

Background: New long-term care insurance (LTCI) certifications and mortality are key outcomes in cohort studies involving older adults; however, the coronavirus disease 2019 (COVID-19)’s comprehensive impacts on these outcomes remain underexplored. We examined the pandemic’s impact on new LTCI applications and all-cause mortality in a metropolitan cohort.

Methods: In 2016, 15,500 individuals aged 65–84 years were randomly selected through stratified sampling from Ota City, Tokyo. LTCI and death records were tracked through December 2023; the monthly LTCI applications and all-cause deaths per 10,000 people were calculated. The COVID-19 pandemic period was defined as beginning in March 2020, after the World Health Organization Director-General characterized the situation as a pandemic on March 11, 2020. Interrupted time-series segmented regression analysis was used to compare trends pre- (January 2018–February 2020) and post-pandemic onset (March 2020–December 2023).

Results: From January 2018 to December 2023, 4,083 new LTCI applications and 2,457 deaths were recorded. New monthly LTCI applications showed a modest upward trend pre-pandemic (0.4 per 10,000 people; 95% confidence interval [CI], 0.1–0.8), declined sharply at the pandemic’s onset (−9.6 per 10,000 people; 95% CI, −16.0 to −3.2), and subsequently increased at a higher rate than pre-pandemic levels (0.8 per 10,000 people; 95% CI, 0.6–1.0). Monthly all-cause deaths remained stable before and immediately after the pandemic’s onset but rose slightly in the post-pandemic period (0.3 per 10,000 people per month; 95% CI, 0.2–0.5).

Conclusion: The COVID-19 pandemic influenced both new LTCI applications and all-cause mortality in this study. These impacts should be carefully considered in cohort studies examining these outcomes.