1. Centre of Surgical Science, Department of Surgery, Zealand University Hospital, Koege, Denmark
2. National Institute of Public Health, University of Southern Denmark, Denmark
3. Department of Surgery, Hvidovre Hospital, University of Copenhagen, Denmark
4. Digestive Disease Centre, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
5. Department of Surgery, Horsens Regional Hospital, University of Aarhus, Aarhus, Denmark