Prevalence of Sarcopenia and Relationships Between Muscle and Bone in Indian Men and Women

Both ethnicity and age are important determinants of musculoskeletal health. We aimed to determine the prevalence of sarcopenia, assess the suitability of current diagnostic guidelines, and explore muscle-bone relationships in adults from India. A total of 1009 young (20-35 years) and 1755 older (> 40 years) men and women from existing studies were collated and pooled for the analysis. Dual-energy x-ray absorptiometry measured areal bone mineral density (aBMD) at the hip and spine, and fat and lean mass; hand dynamometer measured hand grip strength (HGS). Indian-specific cut-points for appendicular lean mass (ALM), ALM index (ALMI) and HGS were calculated from young Indian (-2SD mean) populations. Sarcopenia was defined using cut-points from The Foundations for the National Institutes of Health (FNIH), revised European Working Group on Sarcopenia in Older People (EWGSOP2), Asian Working Group for Sarcopenia (AWGS), and Indian-specific cut-points. Low lean mass cut-points were then compared for their predictive ability in identifying low HGS. The relationship between muscle variables (ALM, ALMI, HGS) and aBMD was explored, and sex differences were tested. Indian-specific cut-points (men-HGS:22.93 kg, ALM:15.41 kg, ALMI:6.03 kg/m²; women-HGS:10.76 kg, ALM:9.95 kg, ALMI:4.64 kg/m²) were lower than existing definitions. The Indian-specific definition had the lowest, while EWGSOP2 ALMI had the highest predictive ability in detecting low HGS (men:AUC = 0.686, women:AUC = 0.641). There were sex differences in associations between aBMD and all muscle variables, with greater positive associations in women than in men. The use of appropriate cut-points for diagnosing low lean mass and physical function is necessary in ethnic populations for accurate sarcopenia assessment. Muscle-bone relationships are more tightly coupled during ageing in Indian women than men.