Leptin Levels, Basal Metabolic Rates, and Insulin Resistance in Obese Pubertal Children

Introduction Obesity in children and adolescents is considered a serious public health problem. The consequences of overweight can last for life. It is extremely important to have formulas to calculate the basal metabolic rate (BMR) that are truly reliable in relation to the individual caloric expenditure. Objectives To investigate the association of serum levels of leptin, lipid profile, and insulin resistance (insuline resistance by Homeostatic Model Assessment [HOMA] index) with the body mass index (BMI) z-score of pubertal obese children. In addition, to compare the basal metabolic rate (BMR) evaluation carried out using bioimpedance (BIA) with the Food and Agricultural Organization/World Health Organization (FAO/WHO) equation. Methods Cross-sectional study including 37 pubertal obese children (aged 7 to 12 years old) seen for the first time in the outpatient care unit specialized in child obesity between June 2013 and April 2014. The participants were assessed regarding anthropometric data, body composition (fat mass) by BIA 310 bioimpedance analyzer (Biodynamic Body Composition Analyser, model 310 - Biodynamics Corporation, Seattle, EUA), and blood pressure. Blood samples were collected to measure glucose, insulin, lipid profile, triglycerides, and leptin. The stage of sexual maturity was determined by self-assessment according to the Tanner scale. Results Higher leptin levels were found in the severe obesity group (p = 0.007) and, as expected, higher BMI (p  Conclusions These results suggest that severely obese children may present leptin resistance in this early stage of life, (since this hormone is higher in these children). It is suggested that health professionals prioritize the calculation of BMR by bioimpedance, since the FAO/WHO equation seems to overestimate the caloric values.