Social participation and functional disability trajectories in the last three years of life: The Japan Gerontological Evaluation Study.

BACKGROUND:Functional disability has various patterns from onset until death. Although social participation is a known protective factor against functional disability among older individuals, it is unclear whether social participation is associated with the trajectory patterns of functional disability prior to death. This study assessed the association between social participation, specifically in horizontal and vertical groups, and the trajectories of functional disability prior to death. METHODS:We used survey data from the 2010 Japan Gerontological Evaluation Study for functionally independent older adults combined with public long-term care insurance system data from 2010 to 2016 (n = 4,502). The outcome variables included five previously identified trajectory patterns using group-based trajectory modeling. As the explanatory variable, we used three definitions of social participation: any group, horizontal group (e.g., sports, hobbies), or vertical group (e.g., political, religious), at least once a month. We used a multinomial logistic regression analysis to calculate odds ratios with 95 % confidence intervals for the identified trajectory patterns. RESULTS:Participation in any groups was significantly less likely to belong to "Accelerated disability" (OR=0.74 [95 % CIs 0.60-0.92]), "Persistently mild disability" (0.68 [0.55-0.84]), and "Persistently severe disability" (0.67 [0.50-0.83]) compared to "Minimum disability." Although participation in horizontal groups was similarly associated with trajectories regardless of gender, vertical groups was not associated with trajectories among males. CONCLUSIONS:Social participation among older adults may be associated with an extended period of living without disabilities before death. This association may differ by gender and social participation group and requires further research.