Plasma leptin concentrations and obesity in relation to insulin resistance syndrome components among school children in Taiwan—The Taipei Children Heart Study

Abstract

OBJECTIVE: Leptin, an adipose tissue-derived product of the obesity (OB) gene, is an important regulator of energy metabolism and may be associated with the occurrence of insulin resistance and diabetes in humans. The purpose of this study was to evaluate the association of plasma leptin concentration with obesity and the components of insulin resistance syndrome (IRS) among 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. Obesity measurements included body mass index (BMI) and waist-to-hip circumference 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 levels. 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 signi®cantly associated with the IRS summary score and each of its components in both genders. Children with higher plasma leptin levels ( b 75th percentiles) have signi®cantly higher BP, TG, insulin levels and IRS score than children with low leptin levels. The associations between plasma leptin level and the IRS components and score were still signi®cant after adjusting for BMI in boys, but less so in girls. In both genders, after adjusting for WHR, plasma leptin levels were still signi®cantly associated with the IRS components and summary score (P`0.001). The ®nal model that included the standard covariates, BMI and leptin, but not WHR, was the most predictive of the IRS summary score among school children. CONCLUSIONS: Insulin resistance syndrome in childhood, characterized by high blood pressure, dyslipidemia, and hyperinsulinemia, may be an early marker of cardiovascular risk. From the present BMI and leptin in combination are the most predictive markers of insulin resistance syndrome among school children in Taiwan.

Plasma leptin is associated with insulin resistance independent of age, body mass index, fat mass, lipids, and pubertal development in nondiabetic adolescents

“…26,27,45,46 Since leptin may modulate IR in ways beyond the effects of adiposity and fat distribution, 47 plasma leptin in combination with BMI has been recognized as a compelling predictor of IR syndrome among school children. 48 In addition, higher leptin concentrations have been found to be associated with impaired arterial distensibility, suggesting that high levels of leptin may have an adverse impact on body fat metabolism, leading to CVD. 49 Therefore, the level of circulating plasma leptin in adolescents may be a powerful predictor for metabolic syndrome disorders and CVD.…”

Insulin resistance and obesity in childhood

“…Data based mainly on animal studies also suggest that increased levels of resistin, another molecule produced by adipose tissue, could impair insulin sensitivity (17). There are also data showing a close relationship between leptin levels and insulin resistance in children (24). Recently, it has also been shown that serum levels of retinol-binding protein 4 (RBP4) correlate with insulin resistance in subjects with obesity as well as in those with impaired glucose tolerance (IGT) or T2DM, therefore suggesting that it could be useful in assessing insulin resistance and the associated risk for complications (25).…”

The gender insulin hypothesis: why girls are born lighter than boys, and the implications for insulin resistance

“…[15][16][17][18][19][20][21][22][23] This sex difference in insulin resistance has usually been attributed to differences in adiposity or pubertal stage, but in studies which have adjusted for these factors 15,18 a residual difference remains which has not been explained. We have shown that girls are substantially (B33%) more insulin resistant than boys at 5 years 24 and in the years leading up to puberty.…”