[1] Univ Nottingham Hosp, Div Gastroenterol, Nottingham NG7 2UH, England
[2] Univ Melbourne, Dept Med, Melbourne, Vic, Australia
[3] Lambeth Walk Grp Practice, Dept Gen Practice & Primary Care, London, England
[4] Univ Michigan, Med Ctr, Div Gastroenterol, Ann Arbor, MI 48109 USA
[5] AstraZeneca Res & Dev Molndal, AZ Biostat, Molndal, Sweden
[6] AstraZeneca Res & Dev Molndal, AZ Biostat, Sodertalje, Sweden
[7] AstraZeneca Res & Dev, Outcomes Res, Molndal, Sweden