Background Increasing evidence suggests associations between osteoarthritis (OA) and the metabolic syndrome (MetS) and its components.
Objectives The objective of this study was to examine whether components of MetS, either singly or additively, are associated with the incidence of severe knee and hip OA, and whether these associations were independent of obesity assessed by body mass index (BMI).
Methods 21,837 participants who had fasting blood lipids, anthropometric and blood pressure measurements during 2003-2007 were selected from the Melbourne Collaborative Cohort Study. MetS was defined as central obesity assessed by waist circumference and any two of dyslipidaemia, hypertension or impaired fasting glycaemia (IGT). The incidence of severe OA requiring total knee and hip replacement was determined by linking the records to the Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR).
Results 685 participants had knee OA and 580 had hip OA. After adjustment for age, gender, country of birth, education and BMI, central obesity (hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.20-1.91) and hypertension (1.25, 1.05-1.50) were associated with increased risk of knee OA. There was a dose-response relationship between the number of MetS components and knee OA risk, independent of BMI: one component 2.11 (1.11-4.01), two components 2.94 (1.57-5.52), three or more components 3.13 (1.66-5.91), p for trend <0.001. No significant associations were observed for hip OA.
Conclusions The cumulative number of MetS components and individual components of the MetS, central obesity and hypertension, are associated with increased risk of severe knee OA, independent of obesity. No association is seen for severe hip OA. The findings suggest different pathogenesis of knee and hip OA and that management of MetS may reduce the risk of knee OA.
Disclosure of Interest None Declared