Obesity has a rising prevalence in children and adolescents, affecting 30% of the paediatric population in Portugal. Leptin is an important hormone involved in the pathogenesis of obesity and has been under investigation as a risk marker for future complications. AIMS: 1. To evaluate the relation between serum leptin levels and body mass index (BMI) and height. 2. To compare leptin levels in obese and non-obese...