Yuito Hosaka

BACKGROUND: Work-related stress is associated with cardiovascular disease (CVD), yet the contributions of specific work-related stressors, support and satisfaction to CVD incidence are not fully understood. Clarifying whether lifestyle behaviors and physiological factors mediate associations between stressors and CVD is essential for targeted prevention. METHODS: In this prospective cohort study, a cohort of 4,820 Japanese workers (3,876 men and 944 women) aged 35-65 years was followed up for CVD incidence from 2007 to 2022. Work-related stressors (e.g., quantitative job overload), support (e.g., supervisor support) and satisfaction (e.g., family life satisfaction) were assessed using the 57-item Brief Job Stress Questionnaire. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD risk. Mediation analysis evaluated the role of lifestyle behaviors (e.g., smoking, alcohol consumption) and physiological factors (e.g., systolic blood pressure, obesity) in the association between stressors and CVD incidence. RESULTS: Quantitative job overload, low supervisor support, and low family life satisfaction were independently associated with increased CVD incidence (HRs ranging from 1.69 to 2.33). A part (24.9%) of the association of quantitative job overload with CVD was significantly mediated by obesity (p=0.007). CONCLUSION: Quantitative job overload, lack of supervisor support, and low family life satisfaction were significant predictors of CVD among Japanese civil servants. These findings suggest that both reducing excessive workload and strengthening support systems inside and outside the workplace may be important for cardiovascular disease prevention among Japanese civil servants.

ABSTRACT Objective To examine the characteristics associated with happiness in Japanese individuals with schizophrenia. Methods A self‐reported online survey was conducted in 2022 among individuals aged 20–75 years, including 223 and 1776 individuals with and without schizophrenia, respectively. We used a modified Poisson regression to assess the factors associated with happiness by calculating the age‐ and sex‐adjusted prevalence ratios (PRs). We examined within‐schizophrenia group differences by age and sex strata, and compared these stratified PRs between groups with and without schizophrenia. Results Among participants with schizophrenia, happiness was significantly associated with self‐rated health status (PR = 1.75), Ikigai (PR = 5.02), depressive symptoms (PR = 0.43), perceived stress (PR = 0.52), cognitive social capital (PR = 2.07), structural social capital (PR = 1.70), social support (PR = 2.40), close friends (PR = 1.88), close relatives (PR = 2.34), and a cohabiting partner (PR = 1.57). Within the schizophrenia group, sex differences were significant for cognitive social capital (men: PR = 3.45; women: PR = 1.43) and cohabiting partners (men: PR = 2.26; women: PR = 1.25), whereas no significant age differences were found. Factors demonstrating a stronger association in participants with schizophrenia than in those without schizophrenia included: Ikigai (with, PR = 5.02; without, PR = 2.91), cognitive social capital (with, PR = 2.07; without, PR = 1.49), and structural social capital (with, PR = 1.70; without, PR = 1.24). Conclusion Happiness in individuals with schizophrenia is associated with physical, mental, and social factors, with social factors exhibiting sex‐related differences.

Better identification of individuals at high risk for type 2 diabetes mellitus (T2DM) requires risk-prediction models incorporating novel predictors. Accordingly, this study aimed to evaluate the merits of including long-term systolic blood pressure variability (SBPV) in predicting T2DM incidence in a Japanese cohort of 3017 participants (2446 men, 571 women; age, 36-65 years) in 2007, who were followed up until March 2019. Consecutive SBP values, recorded between 2003 and 2007, were regressed annually for each participant. The slope and root-mean-square error of the regression line were calculated for each individual to represent SBPV. The significance of SBPV was examined by adding it to a multivariate Cox model incorporating age, sex, smoking status, regular exercise, family history of diabetes, body mass index, blood levels of triglycerides, high-density lipoprotein cholesterol, and fasting blood glucose. The c-index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to compare the performance of the prediction models without (Model 1) and with (Model 2) SBPV. During the 9.8-year follow-up period, 135 participants developed T2DM. Although a statistically significant difference in c-index between Model 1 (0.785) and Model 2 (0.786) was not found, the NRI (8.312% [p < 0.001]) and IDI (0.700% [p = 0.012]) demonstrated that the performance of Model 2 improved compared with Model 1. In conclusion, results suggested that long-term SBPV slightly improved predictive utility for T2DM when added to a conventional prediction model. The study was registered at University Hospital Medical Information Network Clinical Trial registry (UMIN000052544, https://www.umin.ac.jp/).

Background Research on the influence of heart failure on mortality after Alzheimer's disease diagnosis is limited. Objective To evaluate the association between comorbid heart failure and mortality following Alzheimer's disease diagnosis, particularly considering sex differences. Methods We analyzed administrative claims data from Japan, involving 32,363 individuals (11,064 men and 21,299 women) aged 75 or older newly diagnosed with Alzheimer's disease, with 7% having comorbid heart failure. Cox proportional hazard models and population attributable fractions (PAFs) were used to evaluate the association between comorbid heart failure and mortality within one year following Alzheimer's disease diagnosis. Results Individuals with Alzheimer's disease and heart failure had a multivariate-adjusted hazard ratio of 1.51 (95% confidence interval [CI], 1.32–1.73) for mortality during the one-year follow-up period compared to those with Alzheimer's disease and without heart failure. Subgroup analysis by sex revealed a higher mortality hazard ratio in women of 1.63 (95% CI, 1.36–1.95) than that in men of 1.39 (95% CI, 1.13–1.71). Further age and sex subgroup analysis indicated that women across all age brackets—75–79, 80–84, and ≥ 85 years—had higher mortality hazard ratios. The PAF for heart failure increased with age in both sexes, with women having higher PAFs than men, and the sex difference in PAF being most pronounced in the 75–79 age category (men: 1.4%, women: 4.0%). Conclusions Hazard ratios and PAFs for mortality associated with comorbid heart failure in newly diagnosed Alzheimer's disease are higher in women than in men, which persists across all age subgroups.