[1] Bassett Med Ctr, Dept Internal Med, Cooperstown, NY USA
[2] Mayo Clin, Coll Med, Div Gastroenterol & Hepatol, Jacksonville, FL 32224 USA
[3] Augusta Univ, Div Gastroenterol, Dept Internal Med, Med Coll Georgia, Augusta, GA USA
[4] Chiang Mai Univ, Dept Biochem, Fac Med, Chiang Mai, Thailand
[5] Mahidol Univ, Siriraj Hosp, Fac Med, Clin Epidemiol Unit,Dept Res & Dev, Bangkok, Thailand