Background: Social relationships are associated with physical function. However, little scholarly attention has been focused on the effect of changing social factors on physical function.Purpose: This study was designed to examine the effects on physical function of changes in social relationships in adults aged 65 years and older.Methods: This study is part of a longitudinal, prospective cohort study that was conducted on community-dwelling older adults in a suburban area of central Japan. Baseline self-report data were collected in 2011, and a follow-up survey was conducted in 2017. Social relationships were assessed using the Index of Social Interaction, and physical function was evaluated using a subscale of the Kihon Checklist. Chi-square tests, Mann-Whitney U tests, and multiple logistic regression analysis were used to analyze data from 442 older adults who were functionally independent at baseline.
Results: After controlling for covariates in 2011, negative changes in social relationships (odds ratio [OR] = 3.20, 95% CI [1.18, 8.69]) were found to be associated with physical function decline. Moreover, 1-point increases in the different social-relationship values between baseline and follow-up were associated with protective effects against functional decline (OR = 0.71, 95% CI [0.63, 0.80]). Furthermore, median trends between baseline and follow-up revealed associations between decreasing (OR = 4.18, 95% CI [1.53, 11.39]) and continuously low (OR = 2.98, 95% CI [1.42, 6.28]) social relationships and physical function decline.Conclusions/Implications for Practice: The findings support a strong association between negative changes in social relationships and physical function decline and highlight the importance of promoting social relationships to delay physical function decline in older adults.