Weight stability masks sarcopenia in elderly men and women

Skeletal muscle loss or sarcopenia in aging has been suggested in cross-sec tional studies but has not been shown in elderly subjects using appropriate measurement techniques combined with a longitudinal study design. Longitud inal skeletal muscle mass changes after age 60 yr were investigated in inde pendently living, healthy men (n = 24) and women (n = 54; mean age 73 yr) w ith a mean +/- SD follow-up time of 4.7 +/- 2.3 yr. Measurements included r egional skeletal muscle mass, four additional lean components (fat-free bod y mass, body cell mass, total body water, and bone mineral), and total body fat. Total appendicular skeletal muscle (TSM) mass decreased in men (-0.8 +/- 1.2 kg, P = 0.002), consisting of leg skeletal muscle (LSM) loss (-0.7 +/- 0.8 kg, P = 0.001) and a trend toward loss of arm skeletal muscle (ASM; -0.2 +/- 0.4 kg, P = 0.06). In women, TSM mass decreased (-0.4 +/- 1.2 kg, P = 0.006) and consisted of LSM loss (-0.3 +/- 0.8 kg, P = 0.005) and a te ndency for a loss of ASM (-0.1 +/- 0.6 kg, P = 0.20). Multiple regression m odeling indicates greater rates of LSM loss in men. Body weight in men at f ollow-up did not change significantly (-0.5 +/- 3.0 kg, P = 0.44) and fat m ass increased (+1.2 +/- 2.4 kg, P = 0.03). Body weight and fat mass in wome n were nonsignificantly reduced (20.8 +/- 3.9 kg, P = 0.15 and 20.8 +/- 3.5 kg, P = 0.12). These observations suggest that sarcopenia is a progressive process, particularly in elderly men, and occurs even in healthy independe ntly living older adults who may not manifest weight loss.