1. Department of Hygiene, Kyoto Prefectural University of Medicine, Kyoto, Japan
2. Second Department of Internal Medicine, Shiga University of Medical Science, Shiga, Japan
3. Department of Gastroenterological Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
4. Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
5. Tokyo Research Center, Tosoh Corporation, Kanagawa, Japan