Body composition-based obesity and sarcopenic obesity, but not sarcopenia itself, are associated with an increased risk for knee osteoarthritis, according to findings published in Arthritis & Rheumatology.
“Prior studies of obesity and knee OA have mostly defined obesity using anthropometric measures, such as body weight or BMI,” Devyani Misra, MD, MSc, of the Boston University School of Medicine, and colleagues wrote. “Anthropometric measurements are not exclusive measures of adiposity though, but rather reflect the composite of fat, muscle and bone mass. Thus, whether the effects of ‘BMI,’ typically interpreted as effects of obesity, is truly due to excess adiposity versus overall loading due to the combined weight of body mass is not clear.”
To determine how various body mass categories, based on fat and muscle mass, affect a patient’s risk for knee OA, the researchers evaluated participants in the Multicenter Osteoarthritis Study, an NIH-funded, longitudinal cohort of older adults with, or at risk for, OA. For their own study, Misra and colleagues included 1,653 participants without radiographic knee OA at baseline and who completed the follow-up clinic visit at 60 months.
Body composition-based obesity and sarcopenic obesity, but not sarcopenia itself, are associated with an increased risk for knee OA, according to findings.
Based the participants’ fat and muscle mass, as measured by whole-body Dual Energy Xray, Misra and colleagues grouped the individuals into one of four categories — obese, sarcopenic obese, sarcopenic or nonsarcopenic nonobese. They then analyzed the relation between baseline body composition categories and the risk for OA at 60 months, using binomial regression with robust variance estimation.
According to the researchers, both men (RR = 1.73; 95% CI, 1.082.78) and women (RR = 2.29; 95% CI, 1.643.2) in the obese categories demonstrated a significantly increased risk for incident radiographic knee OA. Women who were sarcopenic obese (RR = 1.91; 95% CI, 1.173.11), but not men (RR = 1.74; 95% CI, 0.684.46), were similarly at a greater risk for knee OA. However, sarcopenia itself was not associated with an increased risk for knee OA in men (RR = 0.66; 95% CI, 0.341.3) or women (RR = 0.96; 95% CI, 0.621.49).
“Body composition assessment allows for new insights into the association between obesity and knee OA, especially the finding of the increased risk conferred by sarcopenic obesity,” Misra and colleagues wrote. “Preventive efforts may need to not only focus on reducing obesity, but also ameliorating sarcopenic obesity to reduce the burgeoning incidence and prevalence of knee OA.” – by Jason Laday
Disclosure: Misra reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.