1. Gastroenterology Division; Saiseikai Yokohama-shi Nanbu Hospital; Yokohama Japan
2. Gastroenterology Division; Chigasaki Municipal Hospital; Chigasaki Japan
3. Department of Biostatistics and Epidemiology; Yokohama City University School of Medicine; Yokohama Japan
4. Department of Gastroenterology; Matsushita Memorial Hospital; Osaka Japan
5. Department of Surgery; Miura City Hospital; Miura Japan
6. Department of Internal Medicine; Keiyu Hospital; Yokohama Japan
7. Department of Medical Education; Yokohama City University School of Medicine; Yokohama Japan
8. Division of Endoscopy and Ultrasonography; Kawasaki Medical School; Kurashiki Japan
9. Department of Gastroenterology; Kawasaki Medical School; Kurashiki Japan
10. Department of Gastroenterology and Hepatology; Yokohama City University School of Medicine; Yokohama Japan