1. Department Gastroenterology; Tel-Aviv Medical Center; Tel-Aviv Israel
2. School of Public Health; Faculty of Social Welfare and Health Sciences; University of Haifa; Haifa Israel
3. U.O.C. di Gastroenterologia; Ospedale di Acireale; Azienda Sanitaria Provinciale di Catania; Catania Italy
4. Sackler Faculty of Medicine; Tel-Aviv University; Tel-Aviv Israel