1. Department of General Medicine and Community Health Science; Hyogo College of Medicine; Sasayama Japan
2. Department of Public Health; Aichi Medical University School of Medicine; Nagakute Aichi Japan
3. Department of Gastroenterology; National Hospital Organization Hakodate Hospital; Hakodate Hokkaido Japan
4. Department of Infectious Diseases; Kyorin University School of Medicine; Mitaka Japan
5. Department of Gastroenterology; Kyowakai Medical Corporation Second Kyoritsu Hospital; Kawanishi Hyogo Japan