Association between changes in body composition and physical function after intensive behavioral weight-loss intervention: a Look AHEAD trial subgroup analysis.

BACKGROUND Intentional weight-loss improves physical function among older adults with obesity, despite the associated lean mass loss. However, prior studies have not assessed impacts of weight-loss on physical function and body composition among older adults with type 2 diabetes mellitus (T2DM) and obesity, a population at high-risk for sarcopenia and functional decline. Our objective was to examine differences in body composition changes by physical function status among middle-aged and older adults with T2DM and overweight/obesity participating in an intensive weight-loss intervention of diet and exercise over 12 months. METHODS We conducted a secondary analysis of 12-month data from the Look AHEAD dual-energy X-ray absorptiometry (DXA) substudy among participants randomized to intervention (n=603). Independent variables included DXA-derived percent change in appendicular lean mass (ALM) and fat mass (FM). The dependent variable was SF-36 physical function subscale change categorized as worsened (decrease ≥5), stable (change ±4), or improved (increase ≥5). We examined the associations using ANOVA. RESULTS Overall, participants had a mean age of 58.3 (SD 6.7) and 63% were women - 8% had worsened, 69% stable, and 22% improved physical function. Differences in mean percent ALM change between physical function groups were non-significant (worsened -3.7%; stable -4.8%; improved -5.6% (p=0.05)). Mean percent FM change was significantly different across physical function groups (worsened -9.3%; stable -14.6%; improved -17.9% (p<0.01)). CONCLUSIONS Lean mass loss associated with lifestyle weight-loss intervention does not negatively impact physical function, rather the intervention appears to improve physical function by reducing adiposity among adults with T2DM and overweight/obesity.