[1] Univ Helsinki, Cent Hosp, Dept Gastrointestinal & Gen Surg, Helsinki 00029, Hus, Finland
[2] Bispebjerg Hosp, DK-2400 Copenhagen, Denmark
[3] OUS Rikshosp, Oslo, Norway
[4] Karolinska Univ Sjukhuset, Gastroctr Kirurgi, Stockholm, Sweden
[5] Turku Univ Hosp, Div Digest Surg & Urol, FIN-20520 Turku, Finland
[6] Oslo Univ Hosp, Dept Gastroenterol, Oslo, Norway
[7] Reg Sykehuset, Med Avdelning, Trondheim, Norway
[8] Univ Copenhagen, Hvidovre Hosp, Dept Gastroenterol, DK-2650 Hvidovre, Denmark
[9] Oulu Univ Hosp, Dept Gastrointestinal Surg, Oulu, Finland
[10] Skane Univ Hosp, Endoscopy Unit, Malmo, Sweden