Abstract
BACKGROUND: It has not been clarified whether physical frailty symptoms predict social. frailty. The purpose of this study was to elucidate the effect of physical frailty on social frailty, and to determine which domains of physical frailty predict the development of social frailty. METHODS: We employed a two-year prospective cohort study. A total of 342 socially robust community-dwelling older adults were recruited. We used a modified social frailty screening index consisting of four social domains including financial difficulties, living alone, social activity, and contact with neighbors. Physical frailty status was also assessed at baseline. At the two-year follow-up, we assessed the development of social frailty. Social status was assessed using four social subdomains for the primary analysis. Social status was assessed using the two social subdomains of social activity and contact with neighbors, which would be affected by the physical frailty component, for the secondary analysis. The risk ratios (RR) of physical frailty for the development of social frailty were estimated. RESULTS: Although physical frailty symptoms were not a significant risk factor for future development of social frailty as assessed by four social subdomains (adjusted RR 1.39, 95% CI 0.95-2.15), it became significant when development of social frailty was assessed by the two social subdomains (adjusted RR 1.78, 95% CI 1.10-2.88). An analysis using the physical frailty subdomain showed that slow gait speed (adjusted RR 3.41, 95% CI 1.10-10.53) and weakness (adjusted RR 1.06, 95% CI 1.01-1.12) were independent risk factors for development of social frailty as assessed by two social subdomains. CONCLUSIONS: Physical frailty symptoms predict the development of social frailty. Among physical frailty subdomains, gait speed and muscle strength are critical independent risk factors for future decline in the social aspect. The prevention of physical frailty, especially by maintaining gait ability and muscle strength, may be effective for avoiding social frailty.