[1] Niigata Univ, Grad Sch Med & Dent Sci, Div Gastroenterol & Hepatol, Niigata 9518122, Japan
[2] Niigata Univ, Uonuma Inst Community Med, Dept Gastroenterol & Hepatol, Minami Uonuma 9497302, Japan
[3] Tachikawa Med Ctr, Div Gastroenterol & Hepatol, Nagaoka, Niigata 9408621, Japan
[4] Niigata Univ, Grad Sch Med & Dent Sci, Div Homeostat Regulat & Dev, Niigata 9518122, Japan
[5] Saiseikai Niigata Second Hosp, Div Gastroenterol & Hepatol, Niigata 9501104, Japan