[1] Fremantle Hosp, Dept Gastroenterol, Fremantle, WA, Australia
[2] Univ Western Australia, Dept Med, Nedlands, WA 6009, Australia
[3] Univ Western Australia, Dept Publ Hlth, Nedlands, WA 6009, Australia
[4] Perth Cardiovasc Inst, Nedlands, WA, Australia
[5] Busselton Populat Med Res Fdn, Perth, WA, Australia
[6] Queen Elizabeth II Med Ctr, Pathctr, Perth, WA, Australia
[7] Western Australian Inst Med Res, Brisbane, Qld, Australia
[8] Queensland Inst Med Res, Brisbane, Qld 4006, Australia
[9] Univ Queensland, Brisbane, Qld, Australia