[1] Univ Zurich, Gastroenterol & Hepatol, Zurich, Switzerland
[2] Univ Zurich Hosp, Dept Internal Med, Div Gastroenterol & Hepatol, Zurich, Switzerland
[3] Univ Lausanne, Inst Social & Prevent Med, Healthcare Evaluat Unit, Lausanne, Switzerland
[4] Univ Lausanne, IUMSP, Lausanne, Switzerland
[5] Crohn & Colitis Ctr Clin Source, Gastroenterol, Lausanne, Switzerland
[6] Univ Bern, Inst Social & Prevent Med, Bern, Switzerland
[7] Univ Basel, Gastroenterol & Hepatol, Basel, Switzerland
[8] Univ Zurich, Pediat Gastroenterol, Zurich, Switzerland
[9] Univ Lausanne, Pediat Gastroenterol, Lausanne, Switzerland
[10] CHU Vaudois, Gastroenterol & Hepatol, CH-1011 Lausanne, Switzerland