[1] Shimane Cent Prefectural Hosp, Dept Gastroenterol, Shimane, Japan
[2] Shimane Univ, Sch Med, Dept Gastroenterol & Hepatol, Izumo, Shimane 6938501, Japan
[3] Awaji Prefectural Hosp, Dept Med, Awaji, Japan
[4] Tottori Municipal Hosp, Dept Gastroenterol, Tottori, Japan
[5] Kasai Municipal Hosp, Dept Med, Kasai, Japan