[1] Saiseikai Yokohama Shi Nanbu Hosp, Div Gastroenterol, Yokohama, Kanagawa, Japan
[2] Yokohama City Univ, Sch Med, Dept Biostatist & Epidemiol, Yokohama, Kanagawa, Japan
[3] Yokohama City Univ, Sch Med, Dept Med Educ, Yokohama, Kanagawa, Japan
[4] Yokohama City Univ, Sch Med, Dept Gastroenterol & Hepatol, Yokohama, Kanagawa, Japan
[5] Keiyu Hosp, Dept Internal Med, Yokohama, Kanagawa, Japan
[6] Chigasaki Municipal Hosp, Div Gastroenterol, Chigasaki, Kanagawa, Japan
[7] Matsushita Mem Hosp, Dept Gastroenterol, Osaka, Japan
[8] Miura City Hosp, Dept Surg, Miura, Kanagawa, Japan
[9] Kawasaki Med Sch, Div Endoscopy & Ultrasonog, Kurashiki, Okayama, Japan
[10] Kawasaki Med Sch, Dept Gastroenterol, Kurashiki, Okayama, Japan