[1] Hillingdon Hosp, Dept Gastroenterol & Hepatol, Uxbridge UB8 3NN, Middx, England
[2] Royal Wolverhampton Trust New Cross Hosp, Wolverhampton, England
[3] Cambridge Univ Hosp, Dept Gastroenterol, Cambridge, England
[4] Newcastle Univ, Fac Med Sci, Translat & Clin Res Inst, Newcastle Upon Tyne, Tyne & Wear, England
[5] Newcastle Upon Tyne Hosp NHS Fdn Trust, Dept Gastroenterol, Newcastle Upon Tyne, Tyne & Wear, England
[6] Wolverhampton Univ, Fac Sci & Engn, Wolverhampton, England
[7] Royal Wolverhampton NHS Trust, Dept Gastroenterol, Wolverhampton, England