[1] Triemli Hosp Zurich, Div Gastroenterol & Hepatol, Birmensdorferstr 497, CH-8063 Zurich, Switzerland
[2] Univ Hosp Zurich, Div Gastroenterol & Hepatol, Zurich, Switzerland
[3] Univ Hosp Basel, Div Gastroenterol & Hepatol, Basel, Switzerland
[4] Univ Hosp Lausanne CHUV, Div Gastroenterol & Hepatol, Lausanne, Switzerland
[5] Lindenhof Spital, Div Gastroenterol, Bern, Switzerland
[6] Spital Tiefenau, Div Gastroenterol & Hepatol, Bern, Switzerland
[7] Clin La Source Beaulieu, Crohn & Colitis Ctr, Lausanne, Switzerland
[8] Praxis Romerhof, Olten, Switzerland
[9] Univ Lausanne, Inst Social & Prevent Med IUMSP, Lausanne, Switzerland
[10] Univ Hosp Bern, Clin Visceral Surg & Med, Dept Gastroenterol, Inselspital, Bern, Switzerland
[11] See Spital, Dept Gastroenterol, Horgen, Switzerland
[12] Univ Bern, Inst Social & Prevent Med ISPM, Bern, Switzerland
[13] Natl Univ Malaysia, Div Gastroenterol, Med Ctr, Kuala Lumpur, Malaysia