[1] Univ Hosp Zurich, Dept Gastroenterol & Hepatol, Zurich, Switzerland
[2] Cantonal Hosp Liestal, Dept Gastroenterol & Hepatol, Liestal, Switzerland
[3] Univ Bern, Inst Social & Prevent Med, Bern, Switzerland
[4] Univ Lausanne, Ctr Hosp Univ Vaudois CHUV, Div Gastroenterol & Hepatol, Lausanne, Switzerland
[5] Univ Bern, CTU Bern, Bern, Switzerland
[6] Gastroenterol Univ Hosp Zurich, Ramistr 100, CH-8091 Zurich, Switzerland