Weight stability masks sarcopenia in elderly men and women

Abstract

Skeletal muscle loss or sarcopenia in aging has been suggested in cross-sectional studies but has not been shown in elderly subjects using appropriate measurement techniques combined with a longitudinal study design. Longitudinal skeletal muscle mass changes after age 60 yr were investigated in independently living, healthy men ( n = 24) and women ( n = 54; mean age 73 yr) with a mean ± SD follow-up time of 4.7 ± 2.3 yr. Measurements included regional skeletal muscle mass, four additional lean components (fat-free body 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 tendency for a loss of ASM (−0.1 ± 0.6 kg, P = 0.20). Multiple regression modeling indicates greater rates of LSM loss in men. Body weight in men at follow-up did not change significantly (−0.5 ± 3.0 kg, P = 0.44) and fat mass increased (+1.2 ± 2.4 kg, P = 0.03). Body weight and fat mass in women were nonsignificantly reduced (−0.8 ± 3.9 kg, P= 0.15 and −0.8 ± 3.5 kg, P = 0.12). These observations suggest that sarcopenia is a progressive process, particularly in elderly men, and occurs even in healthy independently living older adults who may not manifest weight loss.