1. Department of Gastrointestinal and Emergency Surgery, Haukeland University Hospital, Bergen, Norway
2. Department of Clinical Science, University of Bergen, Bergen, Norway
3. Department of Gastrointestinal Surgery, Haraldsplass Deaconess Hospital, Bergen, Norway
4. Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway
5. Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway