Objective To assess the prevalence of cardiovascular risk factors in severely obese children and adolescents.

Methods A nationwide prospective surveillance study was carried out from July 2005 to July 2007 where paediatricians were asked to report all new cases of severe obesity in 2–18-year-old children to the Dutch Paediatric Surveillance Unit. Severe obesity is defined by gender and age-dependent cut-off points for body mass index based on Dutch National Growth Studies corresponding to the adult cut-off point of 35 kg/m². Paediatricians were asked to complete a questionnaire for every severely obese child regarding socio-demographic characteristics and cardiovascular risk factors (blood pressure, fasting blood glucose and lipids).

Results In 2005, 2006 and 2007, 94%, 87% and 87%, respectively, of paediatricians in the Netherlands responded to the monthly request from the Dutch Paediatric Surveillance Unit and 500 children with newly diagnosed severe obesity were reported. 72.6% (n=363) of paediatricians responded to a subsequent questionnaire. Cardiovascular risk factor data were available in 255/307 (83%) children who were correctly classified as severely obese. 67% had at least one cardiovascular risk factor (56% hypertension, 14% high blood glucose, 0.7% type 2 diabetes and up to 54% low HDL-cholesterol). Remarkably, 62% of severely obese children aged ≤12 years already had one or more cardiovascular risk factors.

Conclusion A high number (2/3) of severely obese children have cardiovascular risk factors. Internationally accepted criteria for defining severe obesity and guidelines for early detection and treatment of severe obesity and comorbidity are urgently needed.