1. Centre for Clinical Epidemiology and Biostatistics, School of Medicine and Public Health, University of Newcastle, Newcastle, NSW.
2. Menzies Centre for Health Policy, Sydney School of Public Health, University of Sydney, Sydney, NSW.
3. School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Sydney, NSW.
4. Department of Public Health, School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea.