[1] Hiroshima Univ, Hlth Serv Ctr, Higashihiroshima 7398521, Japan
[2] Aichi Canc Ctr, Res Inst, Div Epidemiol & Prevent, Nagoya, Aichi, Japan
[3] Kawasaki Med Sch, Dept Internal Med, Div Gastroenterol, Kurashiki, Okayama, Japan
[4] Hiroshima Univ, Grad Sch Biomed Sci, Programs Biomed Res, Div Frontier Med Sci,Dept Med & Mol Sci, Hiroshima, Japan
[5] Hiroshima Univ Hosp, Dept Endoscopy, Hiroshima, Japan