Association between metabolic syndrome and knee structural change on MRI

To examine the association of metabolic syndrome (MetS) and its components with knee cartilage volume loss and bone marrow lesion (BML) change.

Longitudinal data on 435 participants from a population-based cohort study were analysed. Blood pressure, glucose, triglycerides and high-density lipoprotein (HDL) were collected. MetS was defined based on the National Cholesterol Education Program-Adult Treatment Panel III criteria. MRI of the right knee was performed to measure cartilage volume and BML. Radiographic knee OA was assessed by X-ray and graded using the Altman atlas for osteophytes and joint space narrowing.

Thirty-two percent of participants had MetS and 60% had radiographic knee OA. In multivariable analysis, the following were independently associated with medial tibial cartilage volume loss: MetS, β = -0.30%; central obesity, β = -0.26%; and low HDL, β = -0.25% per annum. MetS, hypertriglyceridaemia and low HDL were also associated with higher risk of BML size increase in the medial compartment (MetS: relative risk 1.72, 95% CI 1.22, 2.43; hypertriglyceridaemia: relative risk 1.43, 95% CI 1.01, 2.02; low HDL: relative risk 1.67, 95% CI 1.18, 2.36). After further adjustment for central obesity or BMI, MetS and low HDL remained statistically significant for medial tibial cartilage volume loss and BML size increase. The number of components of MetS correlated with greater cartilage volume loss and BML size increase (both P for trend <0.05). There were no statistically significant associations in the lateral compartment.

MetS and low HDL are associated with medial compartment cartilage volume loss and BML size increase, suggesting that targeting these factors has the potential to prevent or slow knee structural change.