Reciprocal relationship between physical and social frailty among community-dwelling older adults

Both physical and social frailty are risk factors for major adverse health-related outcomes and influence each other. However, the longitudinal causal relationship between physical and social frailty has not been clarified. This study aimed to determine the reciprocal relationship between physical and social frailty by age group.This study analyzed longitudinal data from a cohort study of older adults aged 65 years or older living in Obu City, Aichi Prefecture, Japan. The study included 2568 participants who participated in both a baseline assessment in 2011 and a follow-up assessment four years later. Participants participated in assessments of physical and cognitive function. Physical frailty was assessed using the Japanese version of the Cardiovascular Health Study criteria. Social frailty was assessed with five questions about daily social activities, social roles, and social relationships. A total frailty score was calculated for each frailty type and used in the cross-lagged panel analysis. The reciprocal relationship between physical and social frailty status was analyzed using a cross-lagged panel model in each of the young-old (n = 2006) and old-old (n = 562) groups.In the old-old group, baseline physical frailty status predicted social frailty status four years later, and social frailty status at baseline predicted physical frailty status four years later. In the young-old group, the effect of social frailty status at baseline on physical frailty at four years was significant; however, the cross-lag effect from baseline physical frailty status to social frailty status at four years was insignificant, indicating that social frailty preceded physical frailty.The reciprocal relationship between physical and social frailty differed by age group. The results of this study suggest the importance of considering age when planning strategies to prevent frailty. Although a causal relationship between both physical and social frailty was observed in old-old, social frailty preceded physical frailty in the young-old, suggesting that early prevention of social frailty is important for the prevention of physical frailty.