RESUMO
<p><b>OBJECTIVE</b>To investigate serum leptin level and its relationship with bone mineral density in obese children from Changsha City.</p><p><b>METHODS</b>One hundred and nineteen obese children and 103 normal children aged 7 to 12 years from five primary schools of Changsha City were enrolled. Obesity was assessed based on the body mass index (BMI). Dual energy X-ray absorptiometry (DEXA) was used to determine bone mineral density (BMD) and body composition. Serum leptin level was measured using enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The obesity group had higher height, weight, BMI, waist circumference and waist to hip ratio (WHR) compared with the normal group (p<0.01). BMD, bone mineral content (BMC), lean mass (LM), fat mass (FM), percentage of body fat (%BF) and leptin concentration in the obesity group were significantly higher than those in the normal group (p<0.01). Serum leptin level was positively correlated with BMD, BMC, LM and FM (r=0.528-0.903, p<0.01). Multiple stepwise regression analysis indicated that BMI and %BF were independent influencing factors for serum leptin level.</p><p><b>CONCLUSIONS</b>Obese children have higher serum leptin level. Serum leptin concentration is significantly correlated with BMD and body composition. BMI and %BF are independent influencing factors for serum leptin level in children.</p>