Relation of serum leptin levels to lipid profile in healthy children

The association of leptin with body fat concentration is well established. There is also experimental evidence of a direct effect of leptin on lipid metabolism. The aim of this study was to evaluate whether leptin levels are related to the corresponding serum lipid levels independently of body fat mass. The study population consisted of 294 phenotypically healthy school children aged 6 to 12 years. Age, sex, body weight, height, Tanner stage, and triceps skinfold thickness were recorded for all participating subjects. A blood sample was drawn in the morning after a 12-hour fast, and serum total, high-density lipoprotein (HDL), and low-density lipoprotein cholesterol; triglyceride; and leptin levels were determined. Multiple regression analysis showed that triglyceride values were positively correlated with the ln(log(e))-transformed leptin levels (beta =.01, P <.001), whereas HDL levels were inversely associated with lnleptin values (beta = -.06, P =.05) after controlling for age, sex, Tanner stage, and body mass index when each of the lipid parameters was tested separately in the regression model. However, the introduction of both triglycerides and HDL values in the same model eliminated the significance of association of HDL with lnleptin, and the positive relationship of triglycerides with lnleptin remained significant. Our results indicate that triglycerides are independently associated with leptin levels after controlling for any known confounder.