1. Division of Gastroenterology and Hepatology; Department of Internal Medicine; Keio University School of Medicine; Tokyo Japan
2. National Hospital Organization Kurihama Medical and Addiction Center; Yokosuka Japan
3. Department of Surgery; Keio University School of Medicine; Tokyo Japan
4. Endoscopy Center; Kawasaki Municipal Ida Hospital; Kawasaki Japan
5. Department of Health Promotion; National Institute of Public Health; Wako Japan