Plasma leptin concentrations and obesity in relation to insulin resistancesyndrome components among school children in Taiwan - The Taipei Children Heart Study

OBJECTIVE: Leptin, an adipose tissue-derived product of the obesity (OB) ge ne, is an important regulator of energy metabolism and may be associated wi th the occurrence of insulin resistance and diabetes in humans. The purpose of this study was to evaluate the association of plasma leptin concentrati on with obesity and the components of insulin resistance syndrome (IRS) amo ng school children in Taiwan. METHODS: After multistage sampling of 85 junior high schools in Taipei, we randomly selected 1264 children (617 boys and 647 girls) aged 12-16 y. Obes ity measurements included body mass index (BMI) and waist-to-hip circumfere nce ratio (WHR). We calculated an IRS summary score for each individual by adding the quartile ranks from the distribution of systolic blood pressure (BP), serum triglyceride (TG), HDL-cholesterol (inverse), and insulin level s. RESULTS: Boys had a higher BMI and WHR, BP and IRS score and lower leptin, insulin, TG and HDL-C levels than girls. BMI. WHR and plasma leptin levels were significantly associated with the IRS summary score and each of its co mponents in both genders. Children with higher plasma leptin levels (>75th percentiles) have significantly higher BP, TG, insulin levels and IRS score than children with low leptin levels. The associations between plasma lept in level and the IRS components and score were still significant after adju sting for BMI in boys, but less so in girls. In both genders, after adjusti ng for WHR, plasma leptin levels were still significantly associated with t he IRS components and summary score (P < 0.001). The final model that inclu ded the standard covariates, BMI and leptin, but not WHR, was the most pred ictive of the IRS summary score among school children. CONCLUSIONS: Insulin resistance syndrome in childhood, characterized by hig h blood pressure, dyslipidemia, and hyperinsulinemia, may be an early marke r of cardiovascular risk. From the present BMI and leptin in combination ar e the most predictive markers of insulin resistance syndrome among school c hildren in Taiwan.