Heterogeneous trajectories of appendicular skeletal muscle mass change and cognitive impairment in community-dwelling middle-aged and older adults

To explore the heterogeneous trajectories of Appendicular Skeletal Muscle mass (ASM) change and their association with cognitive impairment in Chinese community-dwelling middle-aged and older adults, thereby providing evidence for the early identification of high-risk populations and the development of individualized interventions. This study used longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) collected in 2011, 2013, 2015, and 2020. Demographic information and body composition data of participants were collected. ASM was calculated using the height-adjusted ASM index (ASM/height[Formula: see text], kg/m[Formula: see text]). Cognitive function was assessed across four domains: orientation, calculation, memory, and drawing. Group-based Trajectory Modeling (GBTM) was applied to identify ASM change patterns, while logistic regression was used to analyze the association between different trajectories and cognitive impairment. Subgroup analyses were also conducted to explore potential interactions. A total of 7,973 middle-aged and older adults 45 years were included, and three ASM change trajectories were identified: low rapid decline (38.8%), moderate stable (41.1%), and high slow decline (20.1%). Compared with the high slow decline group, the moderate stable group (OR=1.44, 95%CI=1.19–1.75) and low rapid decline group (OR=2.11, 95%CI=1.67–2.71) had significantly higher risks of cognitive impairment. Subgroup analysis revealed a significant interaction between hypertension and ASM trajectories (P