Subgroup Characteristics of the Association between Volunteering and the Risk of Functional Disability Among Older Japanese People: The Tsurugaya Project.

This prospective cohort study aimed to identify the subgroups of older people in which the association between volunteering and incident functional disability is most remarkable by conducting subgroup analyses of age, sex, chronic medical condition, and socio-demographic factors. Participants were 826 Japanese community-dwelling people aged ≥ 70 years who lived in Tsurugaya, Sendai. Volunteering status was assessed with a baseline survey conducted in 2003. Incident functional disability was defined as the first certification of Long-term Care Insurance until 2017. The Cox proportional hazard model was used to estimate the multivariate-adjusted hazard ratios (HR) with 95% confidence intervals (CI) for incident functional disability. Subgroup analyses were conducted according to sex, age, medical history, marital status, and educational level. The risk of incident functional disability was significantly lower in current volunteers (HR 0.70, 95% CI 0.51–0.96) than non-volunteers. This significant association was remarkable in several subgroups such as women, those aged 75 years or over, those living with chronic illnesses, those living without a spouse, and participants with higher educational levels. The association between volunteering and a decreased risk of incident functional disability was remarkable among vulnerable groups such as women, old-old, those living with chronic illnesses, and those living without a spouse.