1. Nottingham Digestive Diseases Biomedical Research Centre, National Institute for Health Research (NIHR), Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, NG7 2UH, UK
2. Division of Hepatobiliary and Transplant Surgery, Freeman Hospital, Freeman Rd, High Heaton, Newcastle upon Tyne NE7 7DN, UK
3. Department of Hepatology and Gastroenterology and Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark ,8200
4. Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Clinical Sciences Building, City Hospital, Nottingham NG5 1PB, UK