Indexed on: 15 Aug '18Published on: 15 Aug '18Published in: Arthritis & Rheumatology
Obesity, defined by anthropometric measures, is a well-known risk factor for knee osteoarthritis (OA) but there is a relative paucity of data regarding the association of body composition (fat and muscle mass) on knee OA risk. We examined the longitudinal association of body composition categories based on fat and muscle mass with incident knee OA risk. We included participants from The Multicenter Osteoarthritis (MOST) Study, a longitudinal cohort of individuals with or at risk for knee OA. Based on body composition (i.e. fat and muscle mass) from whole body Dual Energy X-ray (DXA), subjects were categorized as: 1) obese; 2) sarcopenic obese; 3) sarcopenic; and 4) non-sarcopenic non-obese. We examined the relation of baseline body composition categories to the risk of incident radiographic OA at 60 months using binomial regression with robust variance estimation, adjusting for potential confounders. Among 1653 subjects without radiographic knee OA at baseline, significant increased risk of incident radiographic knee OA was found among obese (women RR 2.29, 95% CI 1.64-3.20; men RR 1.73, 95% CI 1.08-2.78) and sarcopenic obese women (RR 1.91, 95% CI 1.17-3.11), but not men (RR 1.74, 95% CI 0.68-4.46) subjects. Sarcopenia was not associated with knee OA risk (women RR 0.96, 95% CI 0.62-1.49; men RR 0.66; 95% CI 0.34-1.30). In this large longitudinal cohort, we found body composition based obesity and sarcopenic obesity but not sarcopenia, to be associated with knee OA risk. Weight loss strategies for knee OA should focus on obesity and sarcopenic obesity. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.