1. Witten/Herdecke University, HELIOS University Hospital Wuppertal, Centre for Clinical and Translational Research, Department of Pediatrics, Wuppertal, Germany
2. Witten/Herdecke University, Institute of Medical Biometry and Epidemiology, Faculty of Health, Witten, Germany
3. University of Cambridge, Department of Pediatric Gastroenterology, Hepatology and Nutrition, Addenbrooke's Hospital, Cambridge, United Kingdom