[1] Howard Univ Hosp, Dept Med, Washington, DC USA
[2] NCI, Canc Prevent Div, NIH, Bethesda, MD 20892 USA
[3] Univ Penn, Perelman Sch Med, Dept Family Med & Community Hlth, Philadelphia, PA 19104 USA
[4] Howard Univ Hosp, Dept Pathol, Washington, DC USA
[5] Univ Pittsburgh, Dept Med & Epidemiol, Pittsburgh, PA USA
[6] Univ Texas SW Med Ctr Dallas, Div Gastroenterol, Dallas, TX 75390 USA
[7] Georgetown Univ, Dept Med, Div Gastroenterol, Washington, DC USA
[8] NCI, Lab Canc Prevent, Ctr Canc Res, NIH, Bethesda, MD 20892 USA
[9] Meharry Med Ctr, Dept Med, Nashville, TN USA
[10] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[11] NCI, Nutr Epidemiol Branch, Div Canc Epidemiol & Genet, NIH, Bethesda, MD 20892 USA