1. Faculty of Medicine University of Oslo Oslo Norway
2. Department of Pediatrics, Sahlgrenska Academy Gothenburg University Gothenburg Sweden
3. Department of Pediatric Gastroenterology Queen Silvia Children's Hospital Gothenburg Sweden
4. Hans Christian Andersen Children's Hospital Odense University Hospital Odense Denmark
5. Department of Pediatric Research University of Oslo Oslo Norway
6. Division of Pediatric and Adolescent Medicine Oslo University Hospital Oslo Norway