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 the impacts of weight loss on physical function and body composition among older adults with type 2 diabetes mellitus 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 type 2 diabetes mellitus 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 substudy among participants randomized to intervention (n = 603). Independent variables included dual-energy X-ray absorptiometry-derived percent change in appendicular lean mass and fat mass. 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 appendicular lean mass change between physical function groups were nonsignificant (worsened -3.7%; stable -4.8%; improved -5.6%; p = .05). Mean percent fat mass change was significantly different across physical function groups (worsened -9.3%; stable -14.6%; improved -17.9%; p < .01). Conclusions Lean mass loss associated with lifestyle weight-loss intervention does not negatively affect physical function, rather the intervention appears to improve physical function by reducing adiposity among adults with type 2 diabetes mellitus and overweight/obesity.