1. Department of Gastroenterology, Centro Hospitalar Universitário de São João, 4200-427 Porto, Portugal
2. WGO Gastroenterology and Hepatology Training Center, 4200-319 Porto, Portugal
3. Department of Medicine, Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal
4. Gastroenterology and Digestive Endoscopy Unit, Pancreas Institute, Department of Medicine, G.B. Rossi University Hospital, 37134 Verona, Italy