[1] Mayo Clin, Div Gastroenterol & Hepatol, Rochester, MN 55905 USA
[2] Mayo Clin, Div Biomed Stat & Informat, Rochester, MN 55905 USA
[3] Univ Newcastle, Fac Hlth, Callaghan, NSW 2308, Australia
[4] Korea Univ, Coll Med, Dept Internal Med, Div Gastroenterol & Hepatol, Seoul 136705, South Korea