Increased Serum Leptin Level Predicts Bone Mineral Density in Hemodialysis Patients

BACKGROUND: Leptin acts through the adipose-bone axis to regulate bone mineral density (BMD). This study evaluated the relationship between BMD and serum leptin levels in patients on hemodialysis. METHODS: In this cross-sectional study including 98 hemodialysis patients, BMD was measured using dual energy X-ray absorptiometry of the lumbar vertebrae (L2–L4), and serum leptin levels were determined using an enzyme immunoassay. RESULTS: There were 25 (25.5%), 13 (13.3%), and 60 (61.2%) patients with osteopenia, osteoporosis, and normal BMD, respectively. Advanced age (P=0.017); decreased body mass index (BMI, P < 0.001); body height (P < 0.001); prehemodialysis body weight (BW, P < 0.001); post-hemodialysis BW (P < 0.001); waist circumference (P < 0.001); and triglyceride (P=0.015), albumin (P=0.004), and leptin levels (P=0.017) were associated with lower lumbar T scores, whereas increased urea reduction rate (URR, P=0.004) and fractional clearance index for urea (Kt/V, P=0.004) were associated with lower lumbar T scores. The multivariable forward stepwise linear regression analysis with adjustment for sex; age; body height; prehemodialysis BW; BMI; waist circumference; logarithmically transformed triglycerides (log-triglycerides), albumin, creatinine, and leptin (log-leptin) levels; URR; and Kt/V indicated that high serum level of log-leptin (R(2) change = 0.184; P < 0.001), increased prehemodialysis BW (R(2) change = 0.325; P=0.008), male sex (R(2) change = 0.048; P=0.001), young age (R(2) change = 0.044; P=0.012), and increased serum albumin level (R(2) change = 0.017; P=0.044) were significantly and independently associated with lumbar BMD. CONCLUSIONS: Advanced age and female sex were associated with poor BMD, whereas increased BW, serum albumin, and leptin levels were positively associated with BMD in patients on hemodialysis.