1. Department of Gastroenterology, Oslo University Hospital, Oslo, Norway;
2. Unger-Vetlesen Institute, Lovisenberg Diaconal Hospital, Oslo, Norway;
3. Department of Public Health, Oslo Metropolitan University, Oslo, Norway;
4. Institute of Clinical Medicine, University of Oslo, Oslo, Norway;
5. Division of Cancer medicine, Surgery and Transplantation, Oslo University hospital, Oslo, Norway;
6. Department of Clinical Molecular Biology and Laboratory Sciences (EpiGen), Campus Ahus, Akershus University Hospital, Lørenskog, Norway