[1] Univ Melbourne, Melbourne Sch Populat & Global Hlth, Ctr Epidemiol & Biostat, Melbourne, Vic 3010, Australia
[2] Univ Melbourne, Murdoch Childrens Res Inst, Populat Hlth, Melbourne, Vic 3010, Australia
[3] Univ Melbourne, Dept Paediat, Melbourne, Vic 3010, Australia
[4] Royal Childrens Hosp, Dept Gastroenterol, Melbourne, Vic, Australia
[5] Royal Melbourne Hosp, Dept Gastroenterol & Hepatol, Melbourne, Vic, Australia
[6] Canc Council Victoria, Canc Epidemiol Ctr, Melbourne, Vic, Australia
[7] Austin Hlth, Dept Clin Genet, Heidelberg, Vic, Australia
[8] QIMR Berghofer Med Res Inst, Iron Metab Lab, Brisbane, Qld, Australia
[9] Univ Queensland, Clin Res Ctr, Brisbane, Qld, Australia
[10] Royal Brisbane & Womens Hosp, Brisbane, Qld, Australia
[11] Fremantle Hosp, Dept Gastroenterol, Fremantle, WA, Australia
[12] Univ Western Australia, Sch Med & Pharmacol, Nedlands, WA 6009, Australia
[13] Univ Calif Irvine, Dept Epidemiol, Irvine, CA USA