Assessment of lean (muscle) mass and its distribution by dual energy X-ray absorptiometry in healthy Indian females

Abstract

Mean appendicular lean mass increased from the second decade to reach maximum in the fourth decade in Indian women. Post-menopausal females with LMM were significantly older, leaner, and had lower bone mineral density (BMD). Lean mass and ASMI were negatively correlated with age and positively with BMI and BMD at all sites. Sarcopenia is defined by low muscle mass (LMM), strength, and performance. Lean mass can be precisely measured by dual-energy X-ray absorptiometry (DXA). There is no uniform definition of LMM. We undertook this study to prepare percentile charts for lean mass, which serves as a surrogate for muscle mass, in apparently healthy Indian females and correlate it with anthropometric and bone mineral density (BMD) parameters. This cross-sectional study included 1,045 apparently healthy females who participated in a general health examination. They were evaluated for anthropometry, lean mass, and BMD. LMM was defined by appendicular skeletal muscle mass index (ASMI) of <5.5 kg/m(2) (European cutoff) and <5.11 kg/m(2) (<20th centile of this study population cutoff). The study subjects were categorized as pre-menopausal (<50 years) or post-menopausal (>50 years). Mean age and BMI were 44.0 ± 17.1 years and 25.0 ± 5.2 kg/m(2), respectively. Mean total and appendicular lean mass (arm and leg) increased from the second decade to reach maximum in the fourth decade, and then declined. LMM was present in 341 (32.6%) and 157 (15%), respectively, with European and study-based cutoff (ASMI 5.11 kg/m(2)). Twenty percent of post-menopausal females had LMM. Post-menopausal females with LMM were significantly older, leaner, and had lower BMD. Lean mass and ASMI were negatively correlated with age and positively with BMI and BMD at all sites. Peak muscle mass among Indian females is achieved in the fourth decade, and they have lower total and regional lean mass than other ethnic groups.