1. Department of Gastroenterology; National Hospital Organization Hakodate Hospital; Hakodate Japan
2. Department of Public Health; Aichi Medical University School of Medicine; Nagakute Japan
3. Department of General Medicine and Community Health Science; Sasayama Medical Center; Hyogo College of Medicine; Sasayama Japan
4. Department of Internal Medicine; National Health Insurance Bihoro Hosipital; Bihoro Japan
5. Health Sciences University of Hokkaido; Tobetsu Japan