Weight-bearing exercises predispose people with reduced lower body muscle mass to knee OA

Weight-bearing recreational physical activities may lead to knee osteoarthritis (OA) in individuals with low levels of lower-limb muscle mass, according to a study.

Researchers used data from the Rotterdam Study and looked at 5,003 participants (mean age 64.5 years, 56.0 percent women) who had undergone knee x-ray examinations at baseline and follow-up. These participants completed questionnaires that covered total, weight-bearing, and nonweight-bearing recreational physical activities.

The primary outcome was incident radiographic knee OA. Logistic regression within generalized estimating equation framework was used in the analyses.

Over a mean follow-up of 6.33 years, radiographic knee OA was detected in 793 or 9,483 knees (8.4 percent). Weight-bearing activity showed a positive association with the odds of incident radiographic knee OA (odds ratio [OR], 1.22, 95 percent confidence interval [CI], 1.10–1.35; p<0.001). No association was found for nonweight-bearing activity (OR, 1.04, 95 percent CI, 0.95–1.15; p=0.37).

In an analysis stratified by lower-limb muscle mass index (LMI), the association between weight-bearing activity and incident radiographic knee OA was seen only among participants in the lowest LMI tertile (OR, 1.53, 95 percent CI, 1.15–2.04; p=0.003).

The present data highlight an opportunity for tailored physical activity recommendations based on individual muscle mass and osteoarthritis risk, which can help optimize the benefits of physical activity while minimizing the potential of OA development.