[1] Oita Univ, Dept Environm & Prevent Med, Fac Med, 1-1 Idaigaoka,Hasama Machi, Oita 8795593, Japan
[2] Oita Univ, Dept Gastroenterol, Fac Med, 1-1 Idaigaoka,Hasama Machi, Oita 8795593, Japan
[3] Oita Univ, Fac Welf & Hlth Sci, 700 Dannoharu, Oita, Oita 8701192, Japan
[4] Baylor Coll Med, Dept Med Gastroenterol, Houston, TX 77030 USA
[5] Michael E DeBakey VA Med Ctr, Houston, TX USA