Exercise And Dietary Weight Loss In Overweight And Obese Older Adults With Knee OA

Abstract

Knee osteoarthritis (OA), a chronic degenerative joint disease, afflicts as many as 30% of individuals over the age of 65 yrs. and is the leading cause of disability in the United States. Although the cause is still unknown, obesity is a major risk factor. Both obesity and knee OA are known to alter gait patterns. OBJECTIVE The purpose of this study was to determine whether dietary weight loss and exercise, separately and in combination, results in significant changes in gait kinematics relative to a healthy lifestyle control group. METHODS Participants for this study included 151 older (mean age = 68.5 ± 6.2 yrs), overweight and obese adults with knee OA. Participants had been randomized to one of four arms of the Arthritis, Diet and Activity Promotion Trial (ADAPT): diet (D), exercise (E), diet plus exercise (D+E) and healthy lifestyle control (HL). Dietary weight loss consisted of nutrition counseling and reducing total calories consumed with a goal of a 5% loss in body weight over 18 months. The exercise intervention consisted of an hour-long walking and resistance exercise program 3 dwk−1. Three-dimensional high-speed video analysis (60 Hz) was performed using a four-camera Motion Analysis Corporation system. An analysis of covariance was used to examine pair-wise differences between the intervention groups and the control group. RESULTS Weight loss for the four groups was: D:4.4%, E:6.8%, D+E:4.7%, HL:2.5%. Relative to the control group, the D+E group's maximum internal rotation of the hip (D+E: 12.3 ± 1.5 deg; HL = 8.4 ± 1.6 deg) and ankle ROM (D+E:23.8 ± 0.7 deg; HL = 25.6 ± 0.7 deg) were significantly lower (p<.05), and walking velocity (D+E: 110.7 ± 2.7 cm/s; HL = 104.0 ± 2.8 cm/s) was significantly (p<.05) greater after the 18 month intervention. There were no significant differences between both the D or E groups and the HL control group. CONCLUSIONS A diet plus exercise intervention has a significant effect on gait in older, overweight and obese adults with knee osteoarthritis. These improvements further support the use of diet plus exercise as a cornerstone for the treatment of overweight and obese patients with knee OA. Supported by NIH grants 5P60AG10484-07 and M01RR0021.