1. Section of Gastroenterology, S.Elia – Raimondi Hospital, Caltanissetta, Italy
2. Section of Internal Medicine, Villa Sofia – V. Cervello Hospital, Palermo, Italy
3. Internal Medicine, Gastroenterology & Liver Unit, Università Cattolica Sacro Cuore, Rome, Italy
4. Gastroenterology and Endoscopy Unit, Fondazione Istituto San Raffaele Giglio, Cefalù, Italy
5. School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
6. Section of Internal Medicine, DIBIMIS, University of Palermo, Palermo, Italy