Introduction and Objective The association of adolescent obesity with metabolic syndrome (MS) is a major risk factor for both type 2 diabetes mellitus and premature coronary artery disease.

Methods Patients were evaluated at the first visit to an obesity programme. The definition of MS used was based on the NCEP (ATPIII) guidelines modified for paediatric age (⩾3 of the following: concentration of triglycerides ⩾100 mg/dl; high-density lipoprotein (HDL) cholesterol <50 mg/dl (<45 mg/dl for males between 15 and 19 years), waist circumference (WC) ⩾75th percentile (sex specific), fasting glucose concentration ⩾110 mg/dl and systolic/diastolic blood pressure ⩾90th percentile (age, sex and height percentile specific). SPSS 15.0 for Windows was used for statistical analysis.

Results 237 adolescents enrolled in the programme, 53% girls, mean age 13.6 ± 1.6 years, 89% classified as obese and the remainder as overweight. MS was diagnosed in 34.9% of these patients. No adolescent fulfilled the five MS criteria and only three had no criteria at all. Obesity was more prevalent among boys (χ²  =  4.65; p<0.05), increased WC was the most prevalent criterion (98.7%) and high fasting glucose the least (1.3%). Obese adolescents had a significantly higher prevalence of lower HDL values (χ²  =  10.137; p<0.001), increased blood pressure (χ²  =  12.659; p<0.001), increased WC (χ²  =  23.632; p<0.001) and overall MS prevalence (χ²  =  10.21; p<0.001) compared with overweight adolescents. There was a positive correlation between lower HDL and increased triglyceride values (χ²  =  10.139; p<0.001).

Conclusions MS was highly prevalent among the population studied identifying a target subgroup for weight control intensive intervention.