1. Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital , Tampere , Finland
2. Faculty of Social Sciences, Tampere University , Tampere , Finland
3. Faculty of Medicine, Helsinki University , Helsinki , Finland
4. Department of Surgery, Gerontology Research Center (GEREC) , Tampere , Finland
5. Department of Surgery, Päijät-Häme Central Hospital , Lahti , Finland
6. Department of Surgery, Vaasa Central Hospital , Vaasa , Finland
7. Department of Abdominal Surgery, Helsinki University Hospital , Finland
8. Department of Surgery, Satakunta Central Hospital , Pori , Finland
9. Department of Surgery, Central Hospital of Central Finland , Jyväskylä , Finland
10. Department of Surgery, Seinäjoki Central Hospital , Seinäjoki , Finland
11. Department of Surgery, North Karelia Central Hospital , Joensuu , Finland
12. Division of Digestive Surgery and Urology, Turku University Hospital , Turku , Finland
13. Faculty of Medicine, Turku University , Turku , Finland