1. Department of Gastroenterology and Hepatology; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama; Japan
2. Department of Preventive Dentistry; Institute of Health Biosciences; The University of Tokushima Graduate School; Tokushima; Japan
3. Department of Preventive Dentistry; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama; Japan
4. Health Service Center; Okayama University; Okayama; Japan