1. Institute of Social and Preventive Medicine; University of Bern; Bern Switzerland
2. Division of Gastroenterology and Hepatology; University Hospital Zurich; Zurich Switzerland
3. Division of Gastroenterology and Hepatology; Stadtspital Triemli; Zurich Switzerland
4. Institut Universitaire de Médecine Sociale et Préventive; Centre Hospitalier Universitaire Vaudois et Université de Lausanne; Lausanne Switzerland
5. Inserm U954; Department of Hepato-Gastroenterology; University Hospital of Nancy; Lorraine University; Vandoeuvre-lès-Nancy France
6. Division of Gastroenterology and Hepatology; University Hospital Basel; Basel Switzerland
7. Division of Gastroenterology and Hepatology; Centre Hospitalier Universitaire Vaudois et Université de Lausanne; Lausanne Switzerland