Serum Irisin Level Is Positively Associated with Bone Mineral Density in Patients on Maintenance Hemodialysis

BACKGROUND: Irisin is a circulating hormone-like myokine that plays an important role in bone metabolism. We performed a cross-sectional study to investigate whether serum irisin levels correlated with bone mineral density (BMD) in patients on maintenance hemodialysis (MHD). METHODS: Blood samples were obtained from 80 patients on MHD, and serum irisin concentrations were determined using a commercially available enzyme-linked immunosorbent assay. BMD was measured by dual-energy X-ray absorptiometry of the L2–L4 vertebrae. RESULTS: In the study cohort, 10 (12.5%) and 19 (23.8%) patients had osteoporosis and osteopenia, respectively, and 51 (63.75%) patients had normal BMD. Lumbar T-score was negatively associated with body height (P=0.010), body weight (P=0.002), body mass index (BMI, P=0.010), and serum irisin (P < 0.001) and was positively associated with advanced age (P=0.031), female sex (P=0.001), alkaline phosphatase (ALP, P=0.010), urea reduction rate (P=0.018), and fractional clearance index for urea (P=0.020). Multivariable forward stepwise linear regression analysis revealed that high serum logarithmically transformed irisin (log-irisin, β = 0.450, adjusted R(2) change = 0.258; P < 0.001), female sex (β = −0.353, adjusted R(2) change = 0.134; P < 0.001), and serum ALP level (β = −0.176, adjusted R(2) change = 0.022; P=0.049) were significantly and independently associated with lumbar BMD in patients on MHD. CONCLUSIONS: In addition to female sex and serum ALP level, serum irisin level was positively associated with lumbar BMD in patients on MHD.