The purpose of this study is to objectify the effect of diet and exercise on early markers of atherosclerosis in obese children.

The favorable responses of combined treatment strategies, consisting of exercise training and proper diet change, for childhood and adolescent obesity on vascular health are poorly understood. The overall objective of this research project is to investigate the underlying pathophysiological mechanisms that mediate these beneficial effects.

Particularly, the following aims are set forth:

1. To establish the effect of a combined lifestyle intervention, i.e. an individualized exercise training and caloric restriction program, on vascular function (primary endpoint) and structure in a substantial population of obese adolescents.
2. To characterize causal pathways between obesity and endothelial dysfunction with focus on classical risk factors, oxidative and inflammatory stress, metabolic adaptations, bone marrow derived progenitor cells, and blood microparticles.

This research knowledge will be instrumental for risk stratification and clinical management aimed to improve endothelial function by limiting damage and reinforcing regenerative mechanisms in obese adolescents.

Inclusion Criteria: Children with severe obesity

• Younger than 16 yrs: BMI ≥97th sex and age specific BMI-percentile
• Older than 16 yrs: BMI ≥35 kg/m²

Exclusion Criteria:

• Acute or chronic inflammatory process, use of non-steroidal anti- inflammatory drugs or immunosuppressive drugs. (including inhalation corticosteroids).
• Structural heart disease or other cardiac diseases.
• Active malignant hematological disease

10 months