This study attempted to clarify the association between participation in a social group and perceived health among elderly residents of a previously methylmercury-polluted area in Japan.

We conducted a cross-sectional study using eligible subjects from the Shiranui Sea coastal area, where mercury poisoning due to daily intake of fish and shellfish had previously caused some residents to develop the neurological disorder “Minamata disease (MD).” In the present study, we selected subjects aged ≥65 years who had never been diagnosed with MD or applied for medical treatment compensation.

A logistic regression model after adjusting for confounding factors showed that membership in a hobby or volunteer group was associated with good perceived health (odds ratio 1.97, 95 % confidence interval 1.02–3.80).

Our results showed that the effects of membership in social groups on perceived health were not equal across all social groups, with only hobby- or volunteer-related groups having a positive effect on perceived health. Our findings suggested that promoting participation in a social group such as hobby- or volunteer-related groups can help improve perceived health among elderly individuals who had experienced environmental pollution incidents.