1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences , Okayama , Japan
2. Department of Internal Medicine, Japanese Red Cross Himeji Hospital , Okayama , Japan
3. Department of Gastroenterology, National Hospital Organization Shikoku Cancer Center , Matsuyama , Japan
4. Department of Gastroenterology and Hepatology, Kurashiki Central Hospital , Kurashiki , Japan
5. Department of Internal Medicine, Okayama Saiseikai General Hospital , Okayama , Japan
6. Department of Internal Medicine, Fukuyama City Hospital , Fukuyama , Japan
7. Department of Gastroenterology, National Hospital Organization Fukuyama Medical Center , Fukuyama , Japan
8. Department of Internal Medicine, Hiroshima City Hospital , Hiroshima , Japan
9. Department of Gastroenterology, Japanese Red Cross Okayama Hospital , Okayama , Japan
10. Department of Gastroenterology, Iwakuni Clinical Center, National Hospital Organization , Iwakuni , Japan
11. Department of Gastroenterology, Sumitomo Besshi Hospital , Niihama , Japan
12. Department of Endoscopy, Okayama University Hospital , Okayama , Japan