WEIGHT-BEARING activity could contribute to increased odds of radiographic knee osteoarthritis in people with low levels of lower-limb muscle mass, according to recent findings. Although physical activity is known to have numerous health benefits, the study suggests that caution is needed when engaging in weight-bearing activity.
A cohort study was conducted among 5,003 participants (mean age: 64.5 years; 56% female) from the Rotterdam Study, who had X-ray knee measurements done at baseline and follow-up (mean time: 6.33 years). Participants with knee osteoarthritis at baseline were excluded from the study. Data on total weight-bearing and non-weight-bearing recreational physical activities were collected via questionnaires at baseline, and lower-limb muscle mass was also measured by dual X-ray absorptiometry.
The total incidence rate of knee osteoarthritis was 8.4%. Higher weight-bearing activity was associated with increased odds of developing the condition (odds ratio [OR]: 1.22; 95% confidence interval [CI]: 1.10–1.35; P<0.001); whereas non-weight-bearing activity was not (OR: 1.04; 95% CI: 0.95–1.15; P=0.37). When lower-limb muscle mass was taken into consideration, the association of weight-bearing activity and knee osteoarthritis was found in 431 participants with low lower-limb muscle index (OR: 1.53; 95% CI: 1.15–2.04; P=0.003), but not among patients with middle (OR: 0.93) or high (OR: 1.15).
From these findings, the team conclude that the impact of joint loading for adults with low lower-limb muscle mass index may increase the risk of radiographic knee osteoporosis. This underscores the importance of tailored advice for physical activity, particularly for individuals with low muscle mass, in efforts to mitigate the risk. By understanding the differential impact of weight-bearing activity based on muscle mass levels, healthcare providers can better guide patients towards appropriate exercise regimens to promote joint health and reduce the burden of osteoarthritis.
Reference:
Wu Y et al. Weight-bearing physical activity, lower-limb muscle mass, and risk of knee osteoarthritis. JAMA Netw Open. 2024;7(4):e248968.
