1. Department of Gastroenterology Yamagata Prefectural Central Hospital Yamagata Japan
2. Division of General Medicine Center for Community Medicine Jichi Medical University Tochigi Japan
3. Department of Gastroenterology Faculty of Medicine Yamagata University Yamagata Japan
4. Department of Gastroenterological Surgery Yamagata Prefectural Central Hospital Yamagata Japan
5. Division of Public Health Center for Community Medicine Jichi Medical University Tochigi Japan
6. R & D Division of Career Education for Medical Professionals Medical Education Center Jichi Medical University Tochigi Japan
7. Division of Gastroenterology Tohoku University Graduate School of Medicine Miyagi Japan