Slower Knee Cartilage Degeneration Seen After Weight Loss

By Megan Brooks

December 07, 2015

NEW YORK (Reuters Health) - New research suggests that losing weight can slow the progression of knee cartilage degeneration in overweight and obese adults - and the more pounds shed, the better.

"Degenerative joint disease is a major cause of pain and disability in our population, and obesity is a significant risk factor. Once cartilage is lost in osteoarthritis, the disease cannot be reversed," Dr. Alexandra Gersing, of the University of California, San Francisco, said in a statement from the annual meeting of the Radiological Society of North America (RSNA), where she presented her research this week.

In a prior "weight gain" study, the researchers found that patients' knee joint health deteriorated significantly. That provided the impetus to see if weight loss might provide a benefit regarding knee joint health, Dr. Gersing noted in an interview with Reuters Health.

The researchers examined the association between different degrees of weight loss and the progression of knee cartilage degeneration in 506 overweight and obese older adults (BMI 30.2 +/- 3.5) from the Osteoarthritis Initiative, a nationwide study on prevention and treatment of knee osteoarthritis funded by the National Institutes of Health.

The patients had mild to moderate osteoarthritis or risk factors for the disease. Over four years, 253 did not lose weight, 177 lost 5% to 10% of their body weight, and 76 lost more than 10%.

Findings on MRI showed that weight loss was associated with a protective effect against cartilage degeneration, and a larger amount of weight loss appeared more beneficial.

"Cartilage degenerated a lot slower in the group that lost more than 10% of their body weight, especially in the weight-bearing regions of the knee," Dr. Gersing said in the statement. "However, those with 5 to 10% weight loss had almost no difference in cartilage degeneration compared to those who didn't lose weight."

Patients who lost more than 10% body weight also had less pain, whereas pain got worse in those who didn't lose weight or lost only a little bit of weight.

Going forward, the researchers will assess what's behind the beneficial effects of weight loss on knee cartilage. "We have a questionnaire that was distributed to all the members of the study but that data is not released yet," Dr. Thomas Link of University of California San Francisco, who also worked on the study, told Reuters Health.

"That's our next step, to really look specifically at whether it was exercise, or weight loss or a mix of both," he said. "Right now, we just looked at the natural evolution of cartilage degeneration."

The researchers also plan to study the role of diabetes, which is closely linked with obesity, in cartilage degeneration.