Purpose: The objective of this study is to investigate the effects of 12 months of dietary weight loss and/or aerobic exercise on lean mass and the measurements defining sarcopenia in postmenopausal women and to examine the potential moderating effect of serum 25-hydroxyvitamin D (25(OH)D) and age.
Methods: Four hundred thirty-nine overweight and obese postmenopausal women were randomized to diet modification (N = 118), exercise (N = 117), diet + exercise (N = 117), or control (N = 87). The diet intervention was a group-based program with a 10% weight loss goal. The exercise intervention was 45 min·d, 5 d·wk, of moderate-to-vigorous intensity aerobic activity. Total and appendicular lean mass (ALM) were quantified by dual x-ray absorptiometry at baseline and 12 months. A skeletal muscle index (SMI = ALM (kg) / height (m)) and the prevalence of sarcopenia (SMI <5.67 kg·m) were calculated. Serum 25(OH)D was assayed using a competitive chemiluminescent immunoassay.
Results: Dietary weight loss resulted in a significant decrease in lean mass and a borderline significant decrease in ALM and SMI compared with controls. In contrast, aerobic exercise significantly preserved ALM and SMI. Diet + exercise attenuated the loss of ALM and SMI compared with diet alone and did not result in significant loss of total mass or ALM compared with controls. Neither serum 25(OH)D nor age was significant moderators of the intervention effects.
Conclusions: Aerobic exercise added to dietary weight loss can attenuate the loss of ALM during weight loss and may be effective for the prevention and treatment of sarcopenia among overweight and obese postmenopausal women.
Trial registration: ClinicalTrials.gov NCT00470119.