Weight Loss through Diet and Exercise Significantly Improves Knee Osteoarthritis

Weight loss through intensive dieting and moderate exercise reduces pain and increases mobility and function for those with knee osteoarthritis (OA), a new study finds. The study, which included older adults who were overweight or obese, was presented earlier this month at the annual scientific meeting of the American College of Rheumatology in Chicago.

The Intensive Diet and Exercise for Arthritis (IDEA) trial enrolled 454 overweight adults over the age of 55 with knee OA for an 18-month study period. Participants were divided into two groups with a weight-loss goal of 10% of body weight, one with restricted diet and moderate exercise (D+E) and one with restricted diet only (D), as well as a control group that did only exercise (E). In all cases, exercise consisted of one hour of low-to-moderate walking and resistance training three times per week.

In all, 399 (88%) participants completed the study. Their average age was 65.6, 72% were female, 81% were white, their average body mass index was 33.6, and 85% were determined to have bilateral knee OA. During the 18-month study, the D+E group lost 11.4% of body weight on average (10.6 kg), the D group lost 9.5% (8.9 kg), and the E group lost 2.2% (2.0 kg).

Pain, function, and mobility all improved more for the D+E group than the others. Average pain was reduced by 51% for the D+E group, compared with 27% for the D group and 29% for the E group. Average function improved 47% for the D+E group, 30% for the D group, and 24% for the E group. Average walking speed increased 12% for the D+E group, 10% for the D group, and 6% for the E group.

“Clinicians can tell their patients that they will see marked improvement in pain and function in six months or less with intensive diet and exercise,” said lead study author Stephen P. Messier, PhD, a professor and director of the J.B Snow Biomechanics Laboratory at Wake Forest University, in a press release. “Significant between-group differences, however, may not appear (between diet, exercise, and diet combined with exercise) until 18 months. This underscores the need for long-term studies to detect clinically and statistically meaningful results.”