Positive and negative influences of social participation on physical and mental health among community-dwelling elderly aged 65-70 years: a cross-sectional study in Japan.

Obligatory SP had significantly poorer MCS than voluntary participation, occasionally than non-participation; there is a possibility that obligatory SP has harmful influences on mental health of community-dwelling elderly. Measures to promote SP with consideration for individuals' autonomy may be effective in the public health approach to maintaining mental health.