Lower Serum Fibroblast Growth Factor 21 Levels are Associated with Normal Lumbar Spine Bone Mineral Density in Hemodialysis Patients

Recent evidence has indicated that fibroblast growth factor 21 (FGF21) regulates longitudinal bone growth, with increased FGF21 levels leading to bone loss. The present study evaluated the relationship between bone mineral density (BMD) and serum FGF21 levels in patients undergoing hemodialysis (HD). We analyzed blood samples from 95 patients undergoing HD and measured BMD using dual-energy X-ray absorptiometry of the lumbar vertebrae (L2-L4). Serum FGF21 concentrations were determined using a commercially available enzyme-linked immunosorbent assay kit. Thirteen (11.6%) patients were found to have osteoporosis, 27 (28.4%) osteopenia, and 57 patients had normal BMD. Advanced age and decreased body mass index, height, body weight, waist circumference, and triglyceride level were associated with lower lumbar T-scores, as were increased alkaline phosphatase, urea reduction rate, fractional clearance index for urea, and FGF21 levels. Low log-FGF21, increased body mass index, increased pre-HD body weight, and increased logarithmically transformed triglycerides (log-TG) were found to be significantly and independently associated with lumbar BMD by multivariate forward stepwise linear regression analysis with adjustment for significant confounders. We conclude that high serum FGF21 level is negatively associated with BMD in patients undergoing HD.