1. Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy;
2. Endoscopy Unit, Humanitas Clinical and Research Center, IRCCS, Rozzano, Italy;
3. Clinical Effectiveness Research Group, University of Oslo, Oslo, Norway;
4. Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan;
5. University of Kansas School of Medicine and VA Medical Center, Kansas City, Kansas, USA.