Physical frailty and health-related quality of life among Chinese rural older adults: a moderated mediation analysis of physical disability and physical activity

OBJECTIVES: The purpose of this study is to explore the mediating effect of physical disability as well as the role of physical activity (PA) as a moderator in the relationship between physical frailty and health-related quality of life (HRQoL) among rural older adults in China. DESIGN: Cross-sectional analysis. SETTING: Rural households in Shandong of China (Rushan, Qufu, Laolin). PARTICIPANTS AND METHODS: A survey was conducted among 3243 rural older adults. The data were collected using questionnaires measuring physical frailty, physical disability, HRQoL and PA. Bootstrap analyses were employed to explore the mediating effect of physical disability and also the moderating role of PA on physical frailty and HRQoL. RESULTS: After controlling for age and education, physical disability partially mediated the effect of physical frailty on HRQoL (indirect effect=−0.143, 95% CI −0.175 to –0.113), with the mediating effect accounting for 33.71% of the total effect. PA moderated the relationship between physical frailty and physical disability as well as the relationship between physical disability and HRQoL. Specifically, the interaction term between physical frailty and PA significantly predicted physical disability (β=−0.120, t=−7.058, p<0.001), and the interaction term between physical disability and PA also had a significant predictive effect on HRQoL (β=0.115, t=6.104, p<0.001). CONCLUSIONS: PA appears to moderate the indirect effect of physical disability on the association between physical frailty and HRQoL. This study provides support for potential mechanisms in the association between physical frailty and HRQoL. Encouraging rural older adults to increase PA appropriately might improve HRQoL for older adults with physical frailty and physical disability problems.