[1] Yokohama City Univ, Med Ctr, Ctr Inflammatory Bowel Dis, Yokohama, Kanagawa 232, Japan
[2] Yokohama City Univ, Sch Med, Yokohama, Kanagawa 232, Japan
[3] Yokohama Cit Univ, Sch Med, Yokohama, Kanagawa, Japan
[4] Yokohama City Univ, Med Ctr, Dept Lab Med & Clin Invest, Yokohama, Kanagawa 232, Japan
[5] Yokohama City Univ, Med Ctr, Dept Biostat & Epidemiol, Grad Sch Med, Yokohama, Kanagawa 232, Japan
[6] Hiroshima Univ, Dept Surg, Appl Life Sci Inst Biomed & Hlth Sci, Hiroshima, Japan
[7] Hiroshima Univ, Dept Infect Dis, Hiroshima, Japan
[8] Yokohama City Univ, Sch Med, Dept Gastroenterol, Yokohama, Kanagawa 232, Japan