Is unwilling volunteering protective for functional decline? The interactive effects of volunteer willingness and engagement on health in a 3‐year longitudinal study of Japanese older adults

AIM: The present study explored the interactive effects of willingness to volunteer and actual volunteer engagement on the maintenance of functional health among older Japanese adults, using data from a 3-year longitudinal study. METHODS: We used data from the 3-year longitudinal Tokyo Metropolitan Institute of Gerontology Longitudinal Interdisciplinary Study on Aging (1997). We examined 676 older adults aged >65 years from the rural Nangai District who were independent in their basic activities of daily living (BADL). A follow-up study was carried out in 2000. We categorized participants into four groups: "willing volunteers," "unwilling volunteers," "willing non-volunteers" and "unwilling non-volunteers." Logistic regression analyses were carried out to evaluate the interactive effects of willingness to volunteer and actual engagement in volunteering at baseline on BADL decline over a 3-year period. RESULTS: During the follow-up period, 6.6% of willing volunteers, 17.4% of unwilling volunteers, 16.3% of willing non-volunteers and 21.0% of unwilling non-volunteers experienced a decline in BADL. Unwilling volunteers (odds ratio [OR] 2.88, 95% confidence interval [CI] 1.29-6.43) and both non-volunteer groups (willing: OR 2.70, 95% CI 1.28-5.72; unwilling: OR 2.48, 95% CI 1.32-4.64) had significantly higher odds of BADL decline than did willing volunteers. When unwilling non-volunteer was set as the reference, the OR of unwilling volunteers became 1.16 (95% CI 0.55-2.49), suggesting that unwilling volunteers had a similar odds of BADL decline as non-volunteers. CONCLUSION: Volunteer activity is effective for preventing BADL decline only for those who willingly engage. Geriatr Gerontol Int 2019; 19: 673-678.