Clinicians have long known that modest weight loss and exercise benefit patients with knee osteoarthritis by decreasing the load pressure on the joint, resulting in reduced pain and increased mobility. Now, new research findings appearing today in JAMA suggest that a more aggressive approach to such lifestyle changes can produce even better outcomes.
The researchers randomized 454 overweight and obese adults (average body mass index about 33.5) aged 55 years or older to 3 groups: exercise (1 hour of aerobic walking, strength training, and a cool-down period, 3 days a week), diet only (with a weight loss goal of 10% to 15%), or both. At 18 months, 399 participants completed the study. Those in the group that focused on both diet and exercise and those in the diet-only group lost more weight and experienced greater reductions in inflammation compared with those in the exercise-only group. Furthermore, those in the diet and exercise group reported decreases in pain and improved function compared with the exercise-only group.
Lead author Stephen P. Messier, PhD, a professor and director of the J. B. Snow Biomechanics Laboratory at Wake Forest University in Winston-Salem, North Carolina, discusses his team’s findings.
news@JAMA: Why did you do the study?
Dr Messier: We knew from a previous study that modest walking exercise and strength training decreased the progression of disability, so we know exercise should be part of the standard of care. Another study looked at diet with a goal of 5% weight loss and found that when combined with exercise it decreased pain. So we thought if 5% weight loss works, then maybe 10% or 15% would work better.
news@JAMA: And it did work better.
Dr Messier: We were very pleased. Clearly, losing 10% of body weight resulted in less pain, better function, and less inflammation. We also found a dose response with weight loss.
news@JAMA: So should this more aggressive approach be adopted by treating physicians?
Dr Messier: We think it should be part of the standard of care. The big question is, “Can you put this into a community?” We showed it works in a controlled environment; now we want to do a pragmatic trial in the community. When I talk to rheumatologists, they say, “We’d love to do this, but we don’t have the infrastructure. When a patient comes in, we say they need to exercise and lose weight, but we lose them in follow-up.”
news@JAMA: If a 10% loss of weight produced better results than a 5% weight loss, why not suggest 20% or 30% weight reduction?
Dr Messier: What we were trying to do is keep it practical. We found 10% weight loss is obtainable, and we felt it would not be so much that it discouraged people from even trying. We did have people who lost up to 30% of their body weight and we could look at their outcome in secondary analysis, but we haven’t gotten there yet.
news@JAMA: So is weight loss the key to reducing pain and disability from knee osteoarthritis?
Dr Messier: Within the body weight people lost, most of it was fat mass. But there was also loss of muscle mass, and with older adults you don’t want to lose muscle weight. So one of the things we’re thinking of recommending is to combine the intensive diet with even more intensive exercising so muscle mass can be maintained.