1. Department of Gastroenterology, Saga Medical Centre Koseikan, Japan
2. Department of Internal Medicine, Saga Medical School, Japan
3. Department of Internal Medicine, Yuaikai Oda Hospital, Japan
4. Department of Preventive Medicine, Saga Medical School, Japan
5. Department of Internal Medicine and Gastrointestinal Endoscopy, Takagi Hospital, Japan
6. Department of Internal Medicine, Karatsu Red Cross Hospital, Japan
7. Department of Internal Medicine, National Hospital Organization Ureshino Medical Center, Japan
8. Department of Internal Medicine, Imari Arita Kyoritsu Hospital, Japan