The Mediating Effect of Life-style Behaviors on the Association Between Personality Traits and Cardiovascular Disease Mortality Among 29,766 Community-Dwelling Japanese.

OBJECTIVE: Personality traits have been associated with an increased risk of cardiovascular disease (CVD) mortality as well as life-style-related cardiovascular risk factors. However, the mediating effects of life-style behaviors in the association between personality factors and CVD mortality remain insufficiently understood. The aim of the present study was to examine the mediating effect of life-style behaviors on the association between personality traits and CVD mortality. METHODS: We conducted a prospective cohort study of 29,766 Japanese adults aged 40 to 64 years at the baseline and followed them up for 20.8 years from 1990 to 2011. Personality was measured using the Japanese version of the Eysenck Personality Questionnaire - Revised Short Form in 1990. We estimated the multivariable hazard ratio and 95% confidence interval for CVD mortality using Cox proportional hazards models, and explored the mediating effects of life-style behaviors (smoking, drinking, body mass index, and time spent walking) on the association between personality traits and CVD mortality. RESULTS: We documented 1033 deaths due to CVD during 562,446 person-years of follow-up. Psychoticism represents tough-mindedness, aggressiveness, coldness, a lack of deliberateness, and egocentricity. After adjusting for confounding variables, higher psychoticism was associated with CVD mortality (base model hazard ratio = 1.36, 95% confidence interval = 1.14-1.61, p trend < .001). All the life-style behaviors together mediated this association by 19.2%, with smoking having the greatest effect at 15.7%. For the other personality traits, no significant associations with CVD mortality were found. CONCLUSION: The present study demonstrated that life-style behaviors, especially smoking, partially mediate the association between psychoticism and CVD mortality.

Sense of life worth living (ikigai) and incident functional disability in elderly Japanese: The Tsurugaya Project.

OBJECTIVE: To test the hypothesis that elderly persons who feel ikigai (a sense of life worth living) have a lower risk of incident functional disability than those who do not. Recent studies have suggested that ikigai impacts on mortality. However, its impact upon disability is unknown. The aim of the present study was to investigate the association between ikigai and incident functional disability among elderly persons. METHODS: We conducted a prospective cohort study of 830 Japanese elderly persons aged ≥70 years as a comprehensive geriatric assessment in 2003. Information on ikigai was collected by self-reported questionnaire. Data on functional disability were retrieved from the public Long-term Care Insurance database in which participants were followed up for 11 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of functional disability were calculated for three groups delineated according to the presence of ikigai ("no", "uncertain" or "yes") using the Cox proportional hazards regression model. RESULTS: The 11-year incidence of functional disability was 53.3% (442 cases). As compared with the "no" group, the multiple-adjusted HR (95% CI) of incident functional disability was 0.61 (0.36­1.02) for the "uncertain" group and 0.50 (0.30­0.84) for the "yes" group. CONCLUSION: A stronger degree of ikigai is significantly associated with a lower risk of incident functional disability.