Association Between Social Participation and Disability-free Life Expectancy in Japanese Older People: The Ohsaki Cohort 2006 Study

Background: Although social participation has been reported to be associated with significantly lower risks of mortality and disability, to our knowledge, no study has estimated its impact on disability-free life expectancy (DFLE). Therefore, this study aimed to investigate the association between social participation and DFLE in community-dwelling older people. Methods: We analyzed 11-year follow-up data from a cohort study of 11,982 Japanese older adults (age >= 65 years) in 2006. We collected information on the number of social participations using a questionnaire. Using this information, we categorized the participants into four groups. DFLE was defined as the average number of years a person could expect to live without disability. The multistate life table method using a Markov model was employed for calculating DFLE. Results: The results revealed that DFLE according to the number of social participations was 17.8 years (95% confidence interval [CI], 17.3-18.2) for no activities, 20.9 (95% CI, 20.4-21.5) for one activity, 21.5 (95% CI, 20.9-22.0) for two activities, and 22.7 (95% CI, 22.1-23.2) for three activities in men, and 21.8 (95% CI, 21.5-22.2), 25.1 (95% CI, 24.6-25.6), 25.3 (95% CI, 24.7-25.9), and 26.7 years (95% CI, 26.1-27.4), respectively, in women. This difference in DFLE did not change after the participants were stratified for smoking, body mass index, physical activity, and depression. Conclusion: Social participation is associated with longer DFLE among Japanese older people; therefore, encouraging social participation at the population level could increase life-years lived in good health.