1. Division of Digestive Surgery and Urology, Turku University Hospital, Turku, Finland
2. Department of Surgery, University of Turku, Turku, Finland
3. Department of Public Health, University of Turku, Turku, Finland
4. Primary Health Care Unit, Hospital District of Southwest Finland, Turku, Finland
5. University of Namibia, Windhoek, Namibia
6. Department of Surgery, Mikkeli Central Hospital, Mikkeli, Finland
7. Institute of Clinical Medicine, University of Eastern Finland, Joensuu, Finland
8. Department of Surgery, Oulu University Hospital, Oulu, Finland
9. Division of Surgery, Gastroenterology and Oncology, Tampere University Hospital, Tampere, Finland
10. Department of Surgery, Jyväskylä Central Hospital, Jyväskylä, Finland
11. Department of Surgery, Kuopio University Hospital, Kuopio, Finland
12. Department of Surgery, Seinäjoki Central Hospital, Seinäjoki, Finland
13. Department of Biostatistics, University of Turku, Turku, Finland