1. Department of Gastrointestinal Surgery; Graduate School of Medicine; The University of Tokyo; Tokyo
2. Division of Gastroenterology; Kyoto Min-iren Chuo Hospital; Kyoto
3. Department of Clinical Nursing; Shimane University, Faculty of Medicine; Izumo
4. Department of Gastroenterology; Murakami Memorial Hospital, Asahi University; Gifu
5. Niigata University; Niigata; Japan
6. Department of Clinical Research and Informatics; International Clinical Research Center, Research Institute, International Medical Center of Japan