A population-based survey of social capital and instrumental ADL among community-dwelling elderly in a rural area, Japan

To elucidate the impact of social factors such as social capital on instrumental ADL (IADL) among community-dwelling elderly in a rural area, a cross-sectional, population-based survey was conducted using a self-administered questionnaire. The study participants were all residents aged 65 years or more who lived in one of 6 districts in Kurihara city, Miyagi prefecture (n=14097). The study region was randomly selected from 10 districts, stratifying by area (city center, mid-city, and mountain areas). IADL was measured by the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC), developed to measure functional ADL and social activeness in a community, and impaired IADL was defined as usual (below 11; full IADL=13). Participation rate was 83.9%. Overall proportion of impaired IADL was 30.3%. By univariate logistic regression analysis, “few contacts with neighbors” was strongly associated with impaired IADL (OR=10.8, 95%CI=9.5-12.4). “Few/no community activity ever” and “low trust for other people” were also significant factors for impaired IADL (ORs were 3.1 and 1.9, respectively). These results were unchanged if a multivariate logistic regression was employed, in which sex, age and all social factors were included as covariates. Although it is important to interpret the study results with caution as reverse causation is likely occur, such as impaired IADL can interfere with contacting neighbors, this large-scale, population-based study indicates that social network and social activities in the community are significantly associated with IADL among the elderly living in a rural area of Japan. Further follow-up study is needed to clarify the causality.