1. Dept. of Paediatrics Chronic Paediatric Diseases Queen Paola children’s Hospital Antwerp, Belgium
2. Dept. of Epidemiology and Social Medicine University of Antwerp, Belgium
3. Child Psychiatry ZNA General Hospital Middelheim Antwerp and University of Antwerp, Belgium
4. Dept. of Paediatrics University Hospital Antwerp, Belgium
5. Dept. of Paediatric Gastroenterology and Nutrition, University Hospital Brussels, Brussels, Belgium
6. Division of Cardiology, The Hospital for Sick Children, Toronto, Canada.