[1] Guys Kings & St Thomas Sch Med, Dept Gen Practice & Primary Care, London SE11 6SP, England
[2] Royal Adelaide Hosp, Dept Gastroenterol Hepatol & Gen Med, Adelaide, SA 5000, Australia
[3] Northwestern Univ, Sch Med, Dept Med, Div Gastroenterol & Hepatol, Chicago, IL 60611 USA
[4] Univ Sydney, Nepean Hosp, Dept Med, Penrith, NSW 2751, Australia