Background: Increasing prevalence of childhood obesity threatens future health with higher cardiovascular morbidity and thereby reduction of life expectancy. Obesity in childhood is significant related to the metabolic syndrome. Stiffness in the wall of the central arteries increases systolic blood pressure and is an independent risk factor for cardiovascular complications. Measurements of central vascular stiffness and central blood pressure profiles may contribute to define the best principles for treatment of hypertension. Another variable “ambulatory arterial stiffness index” (AASI) is also shown to be a predictor on its own for cardiovascular complications.

Hypothesis: Central heamodynamic variables in obese children are related to the extent of obesity, the metabolic syndrome and insulin resistance, and will predict those obese children who are at risk for developing hypertension and signs of subclinical cardiovascular damage.

Objectives: This study aims to predict those obese children with the highest risk of developing cardiovascular complications / subclinical cardiovascular damage.

Methods: The study group consists of 100 obese children in the age of 12–16 years with a BMI over the 99^th percentile referred to a standardized weight loss programme. The design will be a cross-sectional study including 50 healthy controls and a prospective study of the obese children followed for one year of weight loss intervention. The following haemodynamic variables will be determined; central pulse wave velocity, central aortic blood pressure profiles, heart rate viability (Sphymocor), 24-hour blood pressure measurements including AASI, clinic blood pressure measurements, echocardiography, electrocardiography, urine albumin/creatinine ratio, and blood samples including metabolic and inflammatory parameters.