%0 Journal Article %A Tatsuo Kobayashi %A Yasuo Yoshihara %A Atsuyoshi Samura %A Harumoto Yamada %A Masayuki Shinmei %A Harald Roos %A L Stefan Lohmander %T Synovial fluid concentrations of the C-propeptide of type II collagen correlate with body mass index in primary knee osteoarthritis %D 1997 %R 10.1136/ard.56.8.500 %J Annals of the Rheumatic Diseases %P 500-503 %V 56 %N 8 %X OBJECTIVE To explore in a cross sectional study in patients with primary knee osteoarthritis (OA) the relations between body mass index (BMI), disease stage, and the concentrations of a putative joint fluid marker of type II collagen synthesis, procollagen II C-propeptide.PATIENTS AND METHODS The study included 142 patients with knee OA (median age 68, median BMI 24.1). OA was staged radiologically. The concentrations in synovial fluid of procollagen II C-propeptide were measured by a sandwich enzyme immunoassay.RESULTS Joint fluid concentrations of procollagen II C-propeptide were increased in knees with OA (median 3.7 ng/ml), compared with published reference values for knees in healthy adult volunteers (median 1.3 ng/ml). The concentrations of procollagen II C-propeptide were independently related to both OA stage and BMI (r s = 0.343, p < 0.0001 andr s = 0.253, p = 0.002, respectively).CONCLUSIONS Joint fluid concentrations of this putative marker of collagen II synthesis are high in early and mid-stage OA, but decrease in end stage disease. In addition and for the first time it was shown that the concentrations in synovial fluid of procollagen II C-propeptide increase with increasing BMI in primary knee OA. The increased joint fluid values of this marker in patients with primary knee OA and a high BMI, may reflect increased rates of collagen synthesis in their joint cartilage and could relate to the previously shown increased risk for disease progression in such patients. %U https://ard.bmj.com/content/annrheumdis/56/8/500.full.pdf