[1] Johns Hopkins Univ, Sch Med, Dept Med, Baltimore, MD 21205 USA
[2] Johns Hopkins Med Inst, Dept Med, Baltimore, MD 21205 USA
[3] Johns Hopkins Med Inst, Div Gastroenterol & Hepatol, Baltimore, MD 21205 USA
[4] Johns Hopkins Bloomberg Sch Publ Hlth, Divers Summer Internship Program, Baltimore, MD USA