1. Faculty of Medicine, University of Iceland, Reykjavík, Iceland;
2. Department of Gastroenterology, Landspitali University Hospital, Reykjavik, Iceland;
3. Digestive Disease Center, Copenhagen University Hospital/Herlev, University of Copenhagen, Copenhagen, Denmark;
4. Department of Gastroenterology, University Hospital of Heraklion, University of Crete, Heraklion, Greece