1 Academic Unit of Gastroenterology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK; Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK.
2 Academic Unit of Gastroenterology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK; Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK. Electronic address: david.sanders1@nhs.net.