[1] Indiana Univ, Sch Med, Dept Med, Div Gastroenterol & Hepatol,Roudebush VA Med Ctr, Indianapolis, IN 46202 USA
[2] Richard L Roudebush VA Med Ctr, Indianapolis, IN USA
[3] Univ Minnesota, Sch Med, Dept Family Med & Community Hlth, Minneapolis, MN 55455 USA
[4] Indiana Univ, Dept Biostat, Indianapolis, IN 46202 USA
[5] Regenstrief Inst Inc, Indianapolis, IN USA
[6] Roudebush VAMC, Gastroenterol, Indianapolis, IN USA