[1] Gastroklin, Private Gastroenterol Practice, CH-8810 Horgen, Switzerland
[2] Univ Hosp Zurich, Dept Gastroenterol, CH-8091 Zurich, Switzerland
[3] Med Univ Dept, Kantonsspital Aarau, Div Gastroenterol & Hepatol, CH-5001 Aarau, Switzerland
[4] Aristotle Univ Thessaloniki, Ippokrat Hosp, Dept Internal Med, Med Clin 2, Thessaloniki 54642, Greece
[5] Univ Hosp Zurich, Dept Otorhinolaryngol Head & Neck Surg, CH-8091 Zurich, Switzerland
[6] Aristotle Univ Thessaloniki, Sch Med, Lab Pharmacol 1, Thessaloniki 54124, Greece
[7] Univ Coll London Hosp UCLH, Pancreaticobiliary Med Unit, London NW1 2BU, England
[8] Gastrocentro Plus, Private Gastroenterol Practice, CH-6900 Lugano, Switzerland
[9] Gastroenterol Gruppenpraxis, Private Gastroenterol Practice, CH-3011 Bern, Switzerland
[10] Univ West Macedonia, Sch Healthcare Sci, Midwifery Dept, Macedonia 50100, Greece
[11] 401 Gen Mil Hosp Athens, Dept Gastroenterol, Athens 11525, Attica, Greece