Objective: Physical function and body composition in older obese adults with knee osteoarthritis (OA) were examined after intensive weight loss.
Research Methods and Procedures: Older obese adults (n = 87; ≥60 years; BMI ≥ 30.0 kg/m2) with symptomatic knee OA and difficulty with daily activities were recruited for a 6-month trial. Participants were randomized into either a weight stable (WS) or weight loss (WL) program. Participants in WL (10% weight loss goal) were prescribed a 1000 kcal/d energy deficit diet with exercise 3 d/wk. WS participants attended health information sessions. Body composition and physical function (Western Ontario and McMaster University Osteoarthritis Index, 6-minute walking distance, and stair climb time) were assessed at baseline and 6 months. Statistical analysis included univariate analysis of covariance on 6-month measurements using baseline values as covariates. Associations between physical function and body composition were performed.
Results: Body weight decreased 8.7 ± 0.8% in WL and 0.0 ± 0.7% in WS. Body fat and fat-free mass were lower for WL than WS at 6 months (estimated means: fat = 38.1 ± 0.4% vs. 40.9 ± 0.4%, respectively; fat-free mass = 56.7 ± 0.4 vs. 58.8 ± 0.4 kg, respectively). WL had better function than WS, with lower Western Ontario and McMaster University Osteoarthritis Index scores, greater 6-minute walk distance, and faster stair climb time (p < 0.05). Changes in function were associated with weight loss in the entire cohort.
Discussion: An intensive weight loss intervention incorporating energy deficit diet and exercise training improves physical function in older obese adults with knee OA. Greater improvements in function were observed in those with the most weight loss.