Social participation and the onset of functional disability by socioeconomic status and activity type: The JAGES cohort study.

The impact of social participation on older adults' health may differ by individual socioeconomic status (SES). Consequently, we examined SES effect modification on the associations between types of social activity participation and incident functional disability. Cohort data from the 2003 Japan Gerontological Evaluation Study (JAGES) was utilized. This included individuals who were aged 65 or older and functionally independent at baseline. Analysis was carried out on 12,991 respondents after acquisition of information about their long-term care (LTC) status in Japan. Incident functional disability was defined based on medical certification and LTC information was obtained from municipal insurance databases. Cox proportional hazard regression was conducted for analysis. Results indicated that participants in a sport (hazard ratio [HR]: 0.66; 95% confidence interval [CI]: 0.51, 0.85) or hobby group (HR: 0.69; 95% CI: 0.55, 0.87), or who had a group facilitator role (HR: 0.82; 95% CI: 0.66, 1.02) were less likely to be disabled. While men with 13 or more years of education were less likely to become disabled if they held facilitator roles, this association was weak among men with 0-5years of education (HR of interaction term between 0 and 5years of education and facilitator role dummy variable=3.95; 95% CI: 1.30, 12.05). In conclusion, the association between group participation and smaller risk of the functional disability was stronger among highly educated older adults. Intervention programs promoting social participation should consider participants' socioeconomic backgrounds.