[Association between social participation and frailty among older adults: A longitudinal study from Japan Gerontological Evaluation Study].

Objective　In Japan, measures to prevent frailty among older adults have been implemented. Promotion of social participation is a key measure, but few longitudinal studies have examined the relationship between the types and number of social participation and frailty onset. In this study, we aimed to clarify the relationship between the types and number of social participation and frailty onset using longitudinal data from a large sample of older adults in municipalities in Japan.Methods　We used the 2016 and 2019 panel survey data from the Japan Gerontological Evaluation Study (JAGES). The analysis included 59,545 individuals from 28 municipalities who responded to the JAGES survey in both 2016 (at baseline) and 2019 (at follow-up). We excluded individuals who were dependent on activities of daily living at baseline and non-responders, and those who were frail or with no information about frailty. The dependent variable was frailty onset (≥8 out of 25 points on the basic checklist) at follow-up, and the independent variables were the types and number of types of social participation at baseline. We included 11 variables as potential confounders. We used multiple imputations to complete the missing values and used modified Poisson regression to examine the association between social participation and risk of frailty onset.Results　Of the 59,545 participants, 6,431 (10.8%) were frail onset at follow-up. After multiple imputations (minimum 64,212, maximum 64,287), the risk of frailty onset at follow-up was lower for eight types of social participation, excluding senior citizens' clubs, (nursing care [risk ratio; 0.91], paid work [0.90], volunteer groups [0.87], neighborhood associations [0.87], learning or cultural groups [0.87], activities intended to teach skills or pass experiences to others [0.85], hobby groups [0.81], and sports groups or clubs [0.80]; P<0.05), than no social participation. Additionally, individuals who participated in more types of social participation were at a lower risk of frailty than those with no social participation (P for trend <0.001).Conclusions　The risk of frailty onset was lower among individuals who participated in eight types of social participation at baseline and among those who participated in more types of social participation than those with no social participation. The results suggest that social participation is a useful measure to prevent frailty for extending healthy life expectancy.