[1] Univ Nebraska Med Ctr, Dept Epidemiol, Coll Publ Hlth, Omaha, NE 68198 USA
[2] Univ Nebraska Med Ctr, Coll Med, Dept Internal Med, Div Gastroenterol & Hepatol, Omaha, NE USA
[3] Hubei Third Peoples Hosp, Dept Hepatol, Wuhan, Hubei, Peoples R China
[4] Univ Nebraska Med Ctr, Coll Publ Hlth, Dept Hlth Serv Res & Adm, Omaha, NE USA
[5] Univ Nebraska Med Ctr, Dept Biostat, Coll Publ Hlth, Omaha, NE USA