1. Biochemistry Section, Pathcentre, QE II Medical Centre, Nedlands, Western Australia 6009, Australia
2. Department of Public Health and
3. University Department of Medicine, University of Western Australia, Fremantle, Western Australia 6160, Australia
4. Department of Gastroenterology, Fremantle Hospital, Fremantle, Western Australia 6160, Australia
5. Busselton Population Medical Research Foundation, Perth, Western Australia 6907, Australia
6. Queensland Institute of Medical Research, Brisbane, Queensland 4029, Australia