Effects of sarcopenia on cognitive function in middle-aged and older adults: mediating roles of social participation and instrumental activities of daily living disability

Mechanisms linking sarcopenia and cognitive function among middle-aged and older adults in China remain unclear. We examined whether social participation and instrumental activities of daily living (IADL) disability mediate the longitudinal association between sarcopenia status and cognitive function. We included 7,114 participants from the China Health and Retirement Longitudinal Study (CHARLS) who were followed for 7 years. Associations between sarcopenia status (non-sarcopenia, possible sarcopenia, sarcopenia) and cognitive function were examined using multivariable linear regression. Parallel mediation and moderated mediation effects were tested using nonparametric bootstrapping. After covariate adjustment, sarcopenia was associated with poorer cognitive function compared with non-sarcopenia (B = -0.784, P < 0.001). For possible sarcopenia, IADL disability showed an indirect-only mediating effect (B = -0.055, 95% CI: -0.091 to -0.024). For sarcopenia, both IADL disability (B = -0.133, 95% CI: -0.219 to -0.061) and social participation (B = -0.047, 95% CI: -0.115 to -0.002) partially mediated the association, accounting for 14.94% and 5.28% of the total effect, respectively. In this observational cohort, IADL disability showed an indirect-only mediating effect for possible sarcopenia, while IADL disability and social participation partially mediated the association for sarcopenia. These findings suggest potentially relevant pathways and may inform stage-tailored strategies. Further studies are needed to confirm the proposed pathways and assess causality.