[1] Loyola Univ Med Ctr, Div Gastroenterol, Dept Med, Maywood, IL 60153 USA
[2] Stanford Univ, Dept Med, Sch Med, Div Gastroenterol & Hepatol, Stanford, CA 94305 USA
[3] Kaiser Permanente San Francisco, Dept Gastroenterol, San Francisco, CA USA
[4] Univ Calif Los Angeles, UCLA Ctr Inflammatory Bowel Dis, UCLA Vatche & Tamar Manoukian Div Digest Dis, Los Angeles, CA USA