[Does participation in community gatherings suppress aggravation of functional decline risk among older people? A study based on 2013-2016 data from the Japan Gerontological Evaluation Study].

Objective　Through the amendment of the Long-Term Care Insurance Law in 2014, Japan's Ministry of Health, Labour and Welfare established a general long-term care and prevention project centered on "Kayoinoba" to promote participation in social and physical activities for older people, which included environmental approaches for individual health and well-being through community-building. However, reports show that the effectiveness of long-term care and prevention in Kayoinoba across multiple municipalities is limited. The purpose of this study was to verify the effect of participation in Kayoinoba in reducing the risk of functional decline among older people, using data from 24 municipalities of 10 prefectures nationwide.Methods　This study examined self-administered mail survey data from the Japan Gerontological Evaluation Study. The participants were older people aged ≥65 years who lived in 24 municipalities of 10 prefectures, in 2013 and 2016. The dependent variable was an increase in total score of ≥5 points on a risk assessment scale predicting incident functional disability ("incident functional disability risk score")(Tsuji et al., 2018), and the explanatory variable was existence of participation in a Kayoinoba program. Nine variables were used as the covariates: educational attainment, equivalent income, depression, smoking, drinking, instrumental activities of daily living, incident functional disability risk score in 2013 (including sex and age), living status (whether the person lived alone), and employment status in 2013. We conducted Poisson regression analysis with stratification of the participants into two groups according to age: young older people and old older people. Sensitivity analysis of the possible increase of ≥3 or 7 points in the incident functional disability risk score was also conducted.Results　Of the 3,760 participants in the study, 472 (316 young older people and 156 old older people)[12.6% (11.8%, 14.5%)] participated in Kayoinoba. Compared with those who did not participate in Kayoinoba, the incidence rate ratio (IRR) of increase in risk assessment score was 0.88 (95% confidence interval: 0.65-1.18) for all who did participate, 1.13 (0.80-1.60) in the young older people and 0.54 (0.30-0.96) in the old older people, and was significant in the latter. In addition, similar results were obtained in the sensitivity analysis with the dependent variable as an increase in total score of ≥3 or 7 points on the risk assessment scale predicting incident functional disability.Conclusions　Compared with those who did not participate in Kayoinoba, functional decline risk was suppressed in those who did participate. The IRR was suppressed 46% in old older people. Promoting participation in Kayoinoba may effectively prevent the need for long-term care in old older people.