[1] UCSF, Med GI Hepatol, San Francisco, CA USA
[2] Duke Univ, Gastroenterol, Durham VA Med Ctr, Durham, NC 27706 USA
[3] Duke Univ, Gastroenterol, Durham, NC 27706 USA
[4] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, Baltimore, MD 21218 USA
[5] Johns Hopkins, Baltimore, MD USA
[6] Univ Calif San Francisco, Obstet & Gynecol, San Francisco, CA 94143 USA
[7] Univ Calif San Francisco, Pathol, San Francisco, CA 94143 USA
[8] Univ Southern Calif, Div Gastrointestinal & Liver Dis, Los Angeles, CA USA