[1] Asahikawa Med Univ, Dept Med, Div Gastroenterol & Hematol Oncol, Asahikawa, Hokkaido 0788510, Japan
[2] Hyogo Coll Med, Dept Internal Med, Div Hepatobiliary & Pancreat Dis, Nishinomiya, Hyogo 6638501, Japan
[3] Tokyo Womens Med Univ, Inst Gastroenterol, Tokyo, Japan
[4] Niigata Univ, Grad Sch Med & Dent Sci, Div Gastroenterol & Hepatol, Niigata, Japan
[5] Ehime Univ, Grad Sch Med, Dept Gastroenterol & Metabol, Toon, Japan