ARS | Publication request: Intensive lifestyle intervention improves physical function among obese adults with knee pain: Findings from the Look AHEAD Trial

Submitted to: Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 2010
Publication Date: January 1, 2011
Citation: Foy, C.G., Lewis, C.E., Hairston, K.G., Miller, G.D., Lang, W., Jakicic, J.M., Rejeski, W.J., Ribisl, P.M., Walkup, M.P., Wagenknecht, L.E., the Look AHEAD Research Group. 2011. Intensive lifestyle intervention improves physical function among obese adults with knee pain: Findings from the Look AHEAD Trial. Obesity. 19(1):83-93.

Interpretive Summary: As people age they begin to experience issues such as joint pain and stiffness and decreased mobility. Obesity in older adults can exacerbate these problems. The Look AHEAD study is a trial investigating the long-term health effects of an intensive lifestyle intervention (ILI) versus a usual care group for older adults ages 45-74 that are overweight or obese and have Type 2 diabetes. The goal of the ILI was to teach behavioral weight management strategies regarding diet and physical activity to promote a loss of 10% body weight and an increase in physical activity. The purpose of the current study was to examine whether participants in the ILI reported more improvements in physical function from the beginning of the study to 12 months compared to participants in the usual care condition, and to determine the role of improvements in fitness and weight loss in these differences. Overall, the results of the study show that overweight and obese adults with diabetes and knee pain in the ILI condition reported significant improvement in physical function compared to participants in the usual care condition. The ILI condition also resulted in significant weight loss and improved fitness, which are possible means through which the ILI condition improved physical function. The results of this study suggest that older adults with knee pain may benefit from losing weight and increasing physical activity. These findings are important due to the need to improve the health and quality of life of the growing population of older adults in the United States.

Technical Abstract: Lifestyle interventions have resulted in weight loss or improved physical fitness among individuals with obesity, which may lead to improved physical function. This prospective investigation involved participants in the Action for Health in Diabetes (Look AHEAD) trial who reported knee pain at baseline (n = 2,203). The purposes of this investigation were to determine whether an Intensive Lifestyle Intervention (ILI) condition resulted in improvement in self-reported physical function from baseline to 12 months vs. a Diabetes Support and Education (DSE) condition, and whether changes in weight or fitness mediated the effect of the ILI. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and physical function subscales, and WOMAC summary score. ILI participants exhibited greater adjusted mean weight loss (s.e.) vs. DSE participants (-9.02 kg (0.48) vs. -0.78 kg (0.49); P < 0.001)). ILI participants also demonstrated more favorable change in WOMAC summary scores vs. DSE participants (beta (s.e.) = -1.81 (0.63); P = 0.004). Multiple regression mediation analyses revealed that weight loss was a mediator of the effect of the ILI intervention on change in WOMAC pain, function, and summary scores (P < 0.001). In separate analyses, increased fitness also mediated the effect of the ILI intervention upon WOMAC summary score (P < 0.001). The ILI condition resulted in significant improvement in physical function among overweight and obese adults with diabetes and knee pain. The ILI condition also resulted in significant weight loss and improved fitness, which are possible mechanisms through which the ILI condition improved physical function.