[1] Vestre Viken Hosp Trust, Baerum Hosp, Dept Med, Drammen, Norway
[2] Ostfold Hosp Trust, Dept Res, Gralum, Norway
[3] Univ Oslo, Inst Clin Med, Oslo, Norway
[4] Oslo Univ Hosp, Dept Gastroenterol, Oslo, Norway
[5] Akershus Univ Hosp, Dept Gastroenterol, Lorenskog, Norway
[6] Oslo Univ Hosp, Hormone Lab, Oslo, Norway
[7] Univ Oslo, Coll Appl Sci, Oslo, Norway
[8] Stavanger Univ Hosp, Dept Gastroenterol, Stavanger, Norway
[9] Alesund Hosp Trust, Dept Med, Alesund, Norway
[10] Telemark Hosp Trust, Dept Res & Dev, Skien, Norway
[11] Innlandet Hosp Trust, Dept Med, Gjovik, Norway
[12] Innlandet Hosp Trust, Dept Med, Hamar, Norway
[13] Ostfold Hosp Trust, Dept Gastroenterol, Gralum, Norway
[14] Ostfold Univ Coll, Dept Hlth Sci, Fredrikstad, Norway