1. Department of Gastroenterology, Division of Medicine, Oslo University Hospital, P.O. Box 4956, Nydalen, 0424 Oslo, Norway
2. The Institute of Clinical Medicine, University of Oslo, P.O. Box 1171, Blindern, 0318 Oslo, Norway
3. Department of Nursing Science, Institute of Health and Society, University of Oslo, P.O. Box 1130, Blindern, 0318 Oslo, Norway
4. Østfold University College, K.G. Meldahlsvei 9, 1671 Fredrikstad, Norway
5. Department of Gastroenterology, Østfold Hospital Trust, 1603 Fredrikstad, Norway
6. Research and Development Department, Telemark Hospital Trust, 3710 Skien, Norway