1. Department of Gastroenterology, IRCCS Humanitas Research Hospital, 20089 Milan, Italy
2. Department of Public Health, Experimental and Forensic Medicine, Section of Hygiene, University of Pavia, 27100 Pavia, Italy
3. Clinica San Michele, Savona, 17031 Albenga, Italy
4. IRCCS Policlinico San Matteo, 27100 Pavia, Italy
5. Health Professions Research and Development Unit, IRCCS Policlinico San Donato, 20097 Milan, Italy
6. Medical Department, University Hospital of Parma, 43121 Parma, Italy
7. Department of Biomedical Sciences for Health, University of Milan, 20133 Milan, Italy