1. Department of Gastroenterology, Akershus University Hospital, Lørenskog, Norway
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway
3. Department of Gastroenterology, Herlev Hospital, Herlev, Denmark
4. Abdominal Center, Gastroenterology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
5. Department of Gastroenterology, University Hospital, Linköping, Sweden and Karolinska Institutet, Stockholm, Sweden
6. Department of Gastroenterology, Landspítali, University Hospital of Iceland, Reykjavik, Iceland
7. Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway
8. Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark