Resumen de Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults With Knee Osteoarthritis: The IDEA Randomized Clinical Trial
Stephen P. Messier, Sahnnon L. Mihalko, Claudine Legault, Gary D. Miller, Barbara J. Nicklas
Importance Knee osteoarthritis (OA), a common cause of chronic pain and disability, has biomechanical and inflammatory origins and is exacerbated by obesity.
Objective To determine whether a =10% reduction in body weight induced by diet, with or without exercise, would improve mechanistic and clinical outcomes more than exercise alone.
Design, Setting, and Participants Single-blind, 18-month, randomized clinical trial at Wake Forest University between July 2006 and April 2011. The diet and exercise interventions were center-based with options for the exercise groups to transition to a home-based program. Participants were 454 overweight and obese older community-dwelling adults (age =55 years with body mass index of 27-41) with pain and radiographic knee OA.
Interventions Intensive diet-induced weight loss plus exercise, intensive diet-induced weight loss, or exercise.
Main Outcomes and Measures Mechanistic primary outcomes: knee joint compressive force and plasma IL-6 levels; secondary clinical outcomes: self-reported pain (range, 0-20), function (range, 0-68), mobility, and health-related quality of life (range, 0-100).
Results Three hundred ninety-nine participants (88%) completed the study. Mean weight loss for diet + exercise participants was 10.6 kg (11.4%); for the diet group, 8.9 kg (9.5%); and for the exercise group, 1.8 kg (2.0%). After 18 months, knee compressive forces were lower in diet participants (mean, 2487 N; 95% CI, 2393 to 2581) compared with exercise participants (2687 N; 95% CI, 2590 to 2784, pairwise difference [?]exercise vs diet?=?200 N; 95% CI, 55 to 345; P?=?.007). Concentrations of IL-6 were lower in diet + exercise (2.7 pg/mL; 95% CI, 2.5 to 3.0) and diet participants (2.7 pg/mL; 95% CI, 2.4 to 3.0) compared with exercise participants (3.1 pg/mL; 95% CI, 2.9 to 3.4; ?exercise vs diet + exercise?=?0.39 pg/mL; 95% CI, -0.03 to 0.81; P?=?.007; ?exercise vs diet?=?0.43 pg/mL; 95% CI, 0.01 to 0.85, P?=?.006). The diet + exercise group had less pain (3.6; 95% CI, 3.2 to 4.1) and better function (14.1; 95% CI, 12.6 to 15.6) than both the diet group (4.8; 95% CI, 4.3 to 5.2) and exercise group (4.7; 95% CI, 4.2 to 5.1, ?exercise vs diet + exercise?=?1.02; 95% CI, 0.33 to 1.71; Ppain?=?.004; 18.4; 95% CI, 16.9 to 19.9; ?exercise vs diet + exercise, 4.29; 95% CI, 2.07 to 6.50; Pfunction?
Conclusions and Relevance Among overweight and obese adults with knee OA, after 18 months, participants in the diet + exercise and diet groups had more weight loss and greater reductions in IL-6 levels than those in the exercise group; those in the diet group had greater reductions in knee compressive force than those in the exercise group.
