1Gastroenterology and Hepatology Unit, The Canberra Hospital, Canberra, ACT, Australia, 2Centre for Population Health Research, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia, 3Department of Gastroenterology, Fremantle Hospital, Fremantle, WA, Australia, 4Faculty of Health Sciences, Curtin University, Bentley, WA, Australia, 5School of Medicine and Pharmacology (Fremantle Hospital Campus), The University of Western Australia, WA, Australia, 6Department of Haematology, Fremantle Hospital, Fremantle, WA, Australia, 7Department of Gastroenterology, Fiona Stanley Hospital, Perth, WA, Australia, 8Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, WA, Australia