[1] Tampere Univ Hosp, Dept Gastroenterol & Alimentary Tract Surg, FIN-33521 Tampere, Finland
[2] Univ Tampere, Sch Med, FIN-33101 Tampere, Finland
[3] Seinajoki Cent Hosp, Dept Med, Seinajoki, Finland
[4] Social Insurance Inst, Res Dept, Turku, Finland
[5] Univ Tampere, Sch Hlth Sci, FIN-33101 Tampere, Finland
[6] Univ Tampere, Ctr Child Hlth Res, FIN-33101 Tampere, Finland
[7] Tampere Univ Hosp, FIN-33521 Tampere, Finland
[8] Kuopio Univ Hosp, SF-70210 Kuopio, Finland
[9] North Karelia Cent Hosp, Joensuu, Finland
[10] South Karelia Cent Hosp, Lappeenranta, Finland
[11] Kymenlaakso Cent Hosp, Kotka, Finland
[12] Satakunta Cent Hosp, Pori, Finland
[13] Vaasa Cent Hosp, Vaasa, Finland
[14] Mikkeli Cent Hosp, Mikkeli, Finland
[15] Lansi Pohjas Cent Hosp, Kemi, Finland
[16] Keski Pohjanmaas Cent Hosp, Kokkola, Finland