[1] Thomas Jefferson Univ, Jefferson Med Coll, Div Gastroenterol & Hepatol, Philadelphia, PA 19107 USA
[2] St Louis Univ, Sch Med, Div Gastroenterol & Hepatol, St Louis, MO USA
[3] Univ Penn, Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA USA
[4] Mayo Clin Scottsdale, Div Gastroenterol & Hepatol, Scottsdale, AZ USA
[5] Univ Illinois, Sect Digest & Liver Dis, Chicago, IL USA
[6] Indiana Univ, Ctr Canc, Dept Med, Indianapolis, IN USA
[7] Tulane Univ, Digest Hlth Ctr, Atlanta, GA USA
[8] Univ Michigan, Sch Med, Dept Surg, Ann Arbor, MI USA
[9] Int Fdn Funct Gastrointestinal Disorders, Milwaukee, WI USA
[10] Baylor Coll Med, Sect Hlth Serv Res, Houston, TX USA
[11] Baylor Coll Med, Gastroenterol Sect, Houston, TX USA
[12] Univ N Carolina, Sch Med, Chapel Hill, NC USA
[13] Univ New Mexico, Hlth Sci Ctr, Dept Internal Med, Div Gastroenterol, Albuquerque, NM USA
[14] Univ Iowa, Dept Radiol, Iowa City, IA 52242 USA