1. Gastroenterology Department, Santa Corona Hospital ASL 2 Savonese Viale 25 Aprile, 38 17027 Pietra Ligure SV Italy
2. Gastroenterology Department, Sanremo General Hospital ASL1 Imperiese Sanremo IM Italy
3. Clinical Epidemiology Unit IRCCS Ospedale Policlinico San Martino Genoa Italy
4. Department of Gastroenterology and Hepatology Radboud University Medical Center Nijmegen Netherlands