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The risk of knee osteoarthritis may depend on muscle mass

Physical activities such as running may increase the risk of osteoarthritis in people with lower muscle mass around the knee joints, according to a study published April 30 in JAMA network opened.

In an analysis of X-rays and bone scans, a group from the Erasmus Medical Center in Rotterdam found that carrying out recreational activities was significantly associated with an increased risk of knee osteoarthritis in individuals with low muscle mass in the lower limbs. .

“This study provides evidence for future tailored physical activity recommendations based on an individual’s muscle mass and risk of osteoarthritis,” said lead author Dr. Yahong Wu and colleagues.

During weight-bearing activities such as running, the knees are exposed to the impact of several times your body weight. Such pressure can lead to joint strain and cause early osteoarthritis, the authors explain. Still, it is unclear whether the effects of physical activity on knee osteoarthritis depend on the muscle surrounding the knee joint, they noted.

To investigate these links, researchers studied knee X-rays at baseline and follow-up examinations after six years in a group of 1,881 participants. The subjects were divided into two groups: those who reported weight-bearing activities over the period, such as running or walking, and those who reported non-weight-bearing activities, such as cycling or swimming.

The groups were further stratified according to their muscle mass (tertiles of lower extremity muscle mass index (LMI)) using dual-energy X-ray absorptiometry studies.

According to the findings, among 1,273 individuals who had no knee pain at baseline, weight-bearing activity was significantly associated with radiographic knee osteoarthritis among 431 individuals in the lowest LMI tertile (odds ratio, 1.53, with 1 as reference), but not among patients in the middle and high LMI tertile.

Conversely, the researchers reported no significant association with the likelihood of osteoarthritis in individuals who engaged in non-weight-bearing activities during the study period across all LMI tertiles.

“We observed associations between more taxing recreational physical activity and a greater likelihood of incident radiographic knee osteoarthritis in individuals without knee pain,” the group wrote.

Ultimately, discovering specific conditions under which physical activity acts as a risk or protective factor for osteoarthritis could benefit patients and caregivers, the researchers noted.

“Although physical activity is known to have numerous health benefits, our research suggests that caution should be exercised when performing weight-bearing activities, especially in individuals with low muscle mass in the lower extremities,” the group concluded.

The full study is available here.