Associations between circulating adipokines and bone mineral density in patients with knee osteoarthritis: a cross-sectional study

Background: Associations between adipokines and bone mineral density (BMD) in knee osteoarthritis (OA) remain indistinct. The aim of this study was to investigate the cross-sectional associations between serum levels of adipokines and BMD in patients with knee OA. Methods: This study included 164 patients with symptomatic knee OA from the Anhui Osteoarthritis study. Serum levels of leptin, adiponectin, and resistin were measured using an enzyme-linked immunosorbent assay (ELISA). BMD at total body, spine, hip, and femur were measured by dual-energy X-ray absorptiometry (DXA). Results: In multivariable analyses, serum levels of leptin were significantly associated with reduced BMD at total body, hip, total femur, femoral neck, and femoral shaft (beta = -0.019, 95% CI -0.034 to -0.005; beta = -0.018, 95% CI -0.034 to -0. 003; beta = -0.018, 95% CI -0.034 to -0.002; beta = -0.016, 95% CI -0.032 to 0.000; beta = -0.026, 95% CI -0.046 to -0.006; respectively). Serum levels of adiponectin were significantly and negatively associated with BMD at total femur and femoral shaft (beta = -0.007, 95% CI -0.013 to 0.000; beta = -0.011, 95% CI -0.018 to -0.003; respectively). However, no significant associations were found between serum levels of resistin and BMD at any site measured. Conclusions: Serum levels of leptin and adiponectin were significantly and negatively associated with BMD, suggesting potentially detrimental effects of leptin and adiponectin on BMD in knee OA patients.