1 Department of Metabolism, Digestion, and Reproduction, Imperial College London, London, UK; Department of Gastroenterology, Imperial College Healthcare Trust, London, UK; Inflammatory Bowel Disease Unit, St Mark's Hospital, Harrow, UK. Electronic address: j.alexander@imperial.ac.uk.
2 Department of Metabolism, Digestion, and Reproduction, Imperial College London, London, UK; Department of Gastroenterology, Imperial College Healthcare Trust, London, UK.
3 Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA.
4 Royal Devon University Healthcare NHS Foundation Trust, Exeter, UK.
5 Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK; Edinburgh Inflammatory Bowel Diseases Unit, Western General Hospital, Edinburgh, UK.