Identifying the specific associations between participation in social activities and healthy lifestyle behaviours in older adults

•The type of social activity is important in the context of healthy behaviours.•Participation in multiple social activities leads to engagement in healthy behaviours.•Our findings suggest the importance of both the type and the number of social activities. To examine the longitudinal association between participation in social activities and healthy lifestyle behaviours. This 2-year follow-up study used data from 6168 older adults (73.5 ± 5.3 years; 49% men). We studied participation in five types of social activities at baseline: participation in volunteer, sports, hobbies, senior clubs, and neighbourhood-association groups. The healthy lifestyle behaviours were physical activity (time spent walking: ≥150 min/week; or less), eating habits (dietary variety score: ≥4 points; or less), and intellectual activity (subcomponents of the Tokyo Metropolitan Institute of Gerontology Index of Competence: 4 points; or less). In the follow-up survey, 19% of participants were physically inactive, 53% had unfavourable eating habits, and 34% had diminished intellectual activity. Multilevel modified Poisson regression analysis showed that participation in sports groups was associated with a lower relative risk (RR) of physical inactivity (RR=0.82 [0.72, 0.93]) and unfavourable eating habits (RR=0.95 [0.90, 1.00]). Participation in hobby groups reduced the RR of unfavourable eating habits (RR=0.93 [0.90, 0.97]) and diminished intellectual activity (RR=0.90 [0.85, 0.96]). Participation in volunteering was associated with a lower RR of diminished intellectual activity (RR=0.84 [0.75, 0.95]). Relative to non-participation, participating in two or more social activities was associated with a 9% (95% CI: 0.83, 1.00) lower RR for physical inactivity, a 12% (95% CI: 0.82, 0.95) lower RR for unfavourable eating habits, and a 17% (95% CI: 0.77, 0.89) lower RR for diminished intellectual activity. Both the nature and the number of social activities determine the longitudinal effects of social participation on healthy lifestyle behaviours.