PEDIATRIC HIGHLIGHT Plasma leptin is associated with insulin resistance independent of age, body mass index, fat mass, lipids, and pubertal development in nondiabetic adolescents K-C Huang 1,2,3,4 *, RCY Lin 1,2,4 , N Kormas 3 , L-T Lee 1 , C-Y Chen 1 , TP Gill 2 and ID Caterson 2 1 Department of Family Medicine, National Taiwan University Hospital, Taiwan; 2 Human Nutrition Unit, School of Molecular & Microbial Biosciences, University of Sydney, Australia; 3 Metabolism and Obesity Services, Department of Endocrinology, Royal Prince Alfred Hospital, Missenden Road, Australia; and 4 Ramaciotti Center for Gene Function Analysis, School of Biotechnology & Biomolecular Sciences, University of New South Wales, Australia OBJECTIVE: The rising epidemic worldwide in overweight and obese children requires urgent attention. Leptin has been found to be associated with body weight control and possibly affects insulin sensitivity. Since insulin resistance is associated with obesity in adults and possibly in adolescents, we set out to investigate the association of plasma leptin level with various anthropometric indices, body fat mass (FM), lipids, and insulin resistance (IR) index in nondiabetic adolescents. DESIGN: A cross-sectional study from three high schools in Taipei City in Taiwan. SUBJECTS: A total of 402 nondiabetic subjects (162 boys and 240 girls; age range, 10–19 y; mean age, 15.871.9 y, and mean body mass index (BMI), 24.874.6 kg/m 2 ) were recruited. MEASUREMENTS: The fasting plasma leptin, plasma glucose, insulin, lipids, and anthropometric indices including height, weight, waist (WC) and hip circumferences, and waist-to-hip ratio (WHR) were examined. Total body FM and percentage body fat (FM%) were obtained from dual-energy X-ray absorptiometry. The homeostasis model was applied to estimate the degree of IR. RESULTS: The plasma leptin levels were significantly higher in girls (17.45710.13 ng/ml) than boys (8.8176.71 ng/ml, Po0.001). The plasma leptin levels were positively correlated to BMI, WC, WHR, FM, FM%, and triglycerides (TG). The IR index was positively correlated to BMI, WC, WHR, FM, FM%, TG, and leptin. Using the multivariate linear regression models, we found that plasma leptin remains significantly associated with IR index even after adjusting for age, gender, BMI, FM, WC, Tanner stage, and TG. CONCLUSION: Plasma leptin was associated with IR index independent of age, gender, BMI, FM, WC, Tanner stage, and TG. Plasma leptin levels in adolescents could be a predictor for the development of the metabolic syndrome disorders and cardiovascular diseases. International Journal of Obesity (2004) 28, 470–475. doi:10.1038/sj.ijo.0802531 Published online 2 March 2004 Keywords: leptin; insulin resistance; adolescence; obesity; plasma lipids Introduction The number of obese children and adolescents worldwide has increased considerably. 1–5 As with adults, obesity in childhood is closely related to hypertension, dyslipidemia, type II diabetes, and insulin resistance (IR) syndrome. 6–8 Obese children are at increased risk of becoming obese adults. 9 Furthermore, in a 55 y follow-up study, overweight in adolescence can be used to predict a broad range of adverse health effects that are independent of adult weight. 10 Therefore, obese children and adolescents tend to develop serious medical and psychosocial complications either at the present time or later on in their life, and have a greater risk of adult morbidity and mortality. IR in adults has been found to be associated with obesity, glucose intolerance or diabetes, hypertension, dyslipidemia, and cardiovascular diseases (CVD). There is also mounting evidence that the onset of the IR syndrome may occur in Received 15 April 2003; revised 8 September 2003; accepted 24 September 2003 *Correspondence: Dr K-C Huang, Department of Family Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei, Taiwan 100, Taiwan. E-mail: chin3@ha.mc.ntu.edu.tw International Journal of Obesity (2004) 28, 470–475 & 2004 Nature Publishing Group All rights reserved 0307-0565/04 $25.00 www.nature.com/ijo