Background: Gender disparities in the intention to leave research careers after marriage have not been investigated. This study aimed to clarify the gender-specific associations of marital status and nurturing children with the intention to leave research careers among medical researchers.

Methods: A cross-sectional study was conducted from December 2022 to January 2023. The study was based on a web-based survey targeting medical researchers affiliated with 141 Japanese academic societies. Participants who disagreed with continuing their research careers were classified as intending to leave. Multivariable-adjusted logistic regression analysis was used to evaluate the gender-specific association of marital status and having children with the intention to leave research careers.

Results: Among 3,009 participants, 812 (27.0%) were women, and 342 (11.4%) expressed an intention to leave. A total of 2,481 participants (82.5%) were married, and 2,267 (75.3%) had children. Marital status was associated with intention to leave research careers in opposite directions for men and women, with significant interactions on both multiplicative (P = 0.015) and additive (P = 0.001) scales. Specifically, married men had a significantly lower intention to leave compared with unmarried men (adjusted odds ratio [aOR] 0.63, 95% confidence interval [CI]: 0.40–0.97). In contrast, among women, marriage was associated with a higher intention to leave compared with being unmarried (aOR 1.41, 95% CI: 0.86–2.32), although this increase was not significant. In post hoc subgroup analyses by medical license status, the gender-specific association between marital status and intention to leave research careers was more evident among medical doctors (MDs) than non-MDs, among whom the proportion reporting intention to leave was lower (4% to 6% across groups). However, estimates among non-MD researchers were imprecise due to the small number of events. Similar gender disparities were observed for having children, although the interaction did not reach statistical significance (P for additive interaction = 0.083).

Conclusions: The present results suggest that marital status showed opposite associations with intention to leave research careers between men and women, a pattern primarily observed among MD researchers. Our finding highlights the need to consider gender difference when developing strategies to support retention of medical researchers.

Background: Although marital status is a key social determinant of health, its prognostic relevance in cardiopulmonary exercise testing (CPX) cohorts remains unclear. We aimed to evaluate the association between marital status and mortality risk in patients with cardiac disease (CD) who underwent CPX.

Methods: This retrospective, single-center observational study involved consecutive patients with CD who underwent post-discharge CPX between 2008 and 2020. Participants (mean age: 69 years; 73% male) were categorized as either unmarried (never married, divorced, or widowed) or married. The primary outcome was all-cause mortality, and the secondary outcome was cardiovascular mortality. We used Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Model 1 was adjusted for age and sex to estimate the overall association between marital status and outcomes. Model 2 was adjusted for Model 1 covariates and peak VO₂ to account for objectively measured exercise capacity.

Results: Of 4,681 patients analyzed, 1,117 were unmarried and 3,564 were married. In Model 1, being married was associated with a lower risk of all-cause mortality (aHR: 0.75, 95% CI: 0.62–0.91, P < 0.001). This association persisted after adjusting for peak VO₂ in Model 2 (aHR: 0.79, 95% CI: 0.65–0.96, P = 0.002). For cardiovascular mortality, the estimates were consistent in direction (Model 1; aHR: 0.64, 95% CI: 0.44–0.93, P = 0.019, Model 2; aHR: 0.69, 95% CI: 0.47–1.02, P = 0.061).

Conclusions: In a large CPX cohort of patients with CD, married status was associated with a lower risk of all-cause mortality. The association was attenuated but remained after adjustment for peak VO₂, suggesting that differences in exercise capacity may contribute but do not fully account for the observed association. Marital status should be interpreted as a social marker rather than a causal or interventional exposure, and future studies should clarify modifiable factors related to prognosis.

Background: Evidence regarding the association between ambient polycyclic aromatic hydrocarbon (PAH) mixtures and non-neoplastic gastrointestinal diseases in general populations remains limited. This study examined whether provincial ambient particulate-phase PAH burden was associated with prevalent gastrointestinal disease among middle-aged and older adults in China.

Methods: Provincial annual mean concentrations of particulate-phase PAHs for 2015 were compiled from published monitoring studies across 12 Chinese provinces and linked to participants in the 2015 wave of the China Health and Retirement Longitudinal Study. Gastrointestinal disease was defined as a self-reported physician diagnosis and/or current treatment, excluding tumors and cancer. Using multivariable logistic regression, we estimated odds ratios and 95% confidence intervals for prevalent gastrointestinal disease per doubling (log2) of total PAHs and of 17 individual PAHs, adjusting for demographic, socioeconomic, and health-related covariates. The Benjamini–Hochberg procedure controlled the false discovery rate. Likelihood ratio tests for interaction were used to assess effect modification.

Results: Of 3,671 adults aged 45 years or older, 1,056 (28.8%) reported a gastrointestinal disease. In fully adjusted models, each doubling of total PAH concentration was associated with increased odds of gastrointestinal disease (odds ratio 1.07, 95% confidence interval 1.02–1.12; false discovery rate–adjusted q = 0.014). Following multiple-comparison correction, naphthalene, fluorene, phenanthrene, and pyrene each demonstrated consistent positive associations. The association for total PAHs was more pronounced among non-drinkers (odds ratio 1.43, 95% confidence interval 1.19–1.71; P for interaction = 0.015) and rural residents (odds ratio 1.37, 95% confidence interval 1.15–1.65; P for interaction = 0.035).

Conclusions: Higher provincial ambient particulate-phase PAH burden was associated with a greater prevalence of self-reported non-neoplastic gastrointestinal disease among middle-aged and older Chinese adults, with potential heterogeneity by residence and alcohol consumption. Given the cross-sectional design and province-level exposure assignment, longitudinal studies with individual-level exposure assessment and validated outcomes are needed.

Background: New tobacco products, including heated tobacco products and electronic cigarettes, are rapidly increasing in popularity among younger populations worldwide, particularly in Japan. Thus, clarifying the effects of both active and passive smoking of new tobacco products during pregnancy is an urgent public health concern. We focused on nausea and vomiting in pregnancy (NVP) which is traditionally and epidemiologically considered an indicator of healthy pregnancy progression. In this study, we classified maternal and paternal smoking status focussing on new tobacco product use and investigated its association with the absence of NVP.

Methods: This cross-sectional study used control data from a case–control study designed to explore modifiable factors for anorectal malformations. The questionnaire survey was conducted within seven Japanese regions between December 2019 and March 2023, enrolling a total of 1,522 postpartum women. The study included 1,450 postpartum women who delivered singleton babies and provided complete information. The main outcome was the absence of NVP. The exposure was the smoking status of mothers and their partners, classified into four categories: dual users (combustible cigarettes and new tobacco products), new tobacco product-only users, combustible cigarette-only users, and non-smokers (reference). Logistic regression analysis was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the absence of NVP.

Results: Based on maternal smoking status, the absence of NVP was reported in 27.1% of dual users, 25.0% of new tobacco product–only users, 18.0% of combustible cigarette–only users, and 15.2% of non-smokers. Maternal dual use was associated with an increased OR of the absence of NVP (adjusted OR = 2.07, 95% CI: 1.02–4.22). After restricting to non-smoking mothers, the adjusted OR for paternal combustible cigarette smoking was 2.62 (95% CI: 1.25–5.50).

Conclusion: Our main finding was the positive association between maternal dual use of new tobacco products and combustible cigarettes during pregnancy and the absence of NVP. This suggests that smoking cessation guidance during pregnancy, including new tobacco products, is particularly warranted.

Trial registration: Not applicable.

Background: Thyroid hormones support endothelial repair, whereas bedtime snacking is linked to a higher risk of chronic kidney disease (CKD). Since endothelial dysfunction is a core feature of CKD, bedtime snacking could potentially contribute to subclinical hypothyroidism (SCH) by elevating the demand for endothelial repair. This study aimed to explore the association between bedtime snacking and SCH.

Method: In this cross-sectional study, 1,478 Japanese individuals aged 40–69 years with normal thyroid function were enrolled; normal thyroid function was defined as free triiodothyronine (T3) and free thyroxine (T4) levels within the reference ranges and the absence of thyroid-related medication use. Individuals with elevated serum concentrations of TSH (>4.01 µIU/mL) were defined as having SCH. Bedtime snacking was determined in the basis of participants’ affirmation to the question “Do you consume a night meal or snack after dinner, within two hours of bedtime, three or more times per week? (Yes, No)”.

Results: In the study population, 263 individuals reported a bedtime snacking habit, whereas SCH was identified in 81 individuals. A statistically significant association was found between bedtime snacking and SCH. The sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (CI) were 1.77 (1.05, 2.99). This association remained significant after additional adjustment for skipping breakfast and late dinner; 1.83 (1.07, 3.11), and further adjustment for free T4, atherosclerosis, hypertension, diabetes, CKD, and thyroid cysts; 1.93 (1.11, 3.35), respectively.

Conclusion: Bedtime snacking is positively associated with SCH, potentially due to an increased physiological demand for endothelial repair. This finding is not only an efficient tool for diagnosing the early stages of endothelial and thyroid dysfunction, but also for clarifying the mechanism underlying the regulation of thyroid hormones related to endothelial health.