Muscle Functional Capacity Modifies the Association Between Adiposity and Sarcopenia: Evidence from Two Population-Based Cohorts

The study examined the relationship between adiposity (excessive body fat) and sarcopenia (muscle loss) in older adults using two independent cohorts: the Chinese CHARLS cohort (15,701 participants) and the US NHANES cohort (10,730 participants). Researchers tested 536 interactions between various fat measures and muscle functional indicators. They found that the relationship between adiposity and sarcopenia was strongly modified by relative grip strength (the ratio of maximum grip strength to body weight). In individuals with high grip strength, higher adiposity was associated with lower sarcopenia risk (approximately 10-fold stronger effect), whereas in those with low grip strength, this protective effect was not observed. These findings were independently confirmed in the US cohort. The results suggest that integrating grip strength assessment into adiposity evaluation may improve sarcopenia risk stratification in older adults.