[1] Univ Manchester, Fac Biol Med & Hlth, Manchester, Lancs, England
[2] Salford Royal NHS Fdn Trust, Dept Gastroenterol, Salford M6 8HD, Lancs, England
[3] Salford Royal NHS Fdn Trust, Dept Pathol, Salford, Lancs, England
[4] Salford Royal NHS Fdn Trust, Dept Upper GI Surg, Salford, Lancs, England
[5] Acute Pennine NHS Fdn Trust, Rochdale Infirm, Dept Gastroenterol, Rochdale, England
[6] Univ Manchester, DEG Div, FBMH, GI Sci, Manchester, Lancs, England