1. School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia
2. Clinical Research Design, IT, and Statistical Support (CReDITSS) Unit, Hunter Medical Research Institute, University of Newcastle, New Lambton, New South Wales, Australia
3. Department of General Medicine, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
4. Tobacco Control Unit, Cancer Council NSW, Sydney, New South Wales, Australia
5. Westmead Hospital, Westmead, Sydney, New South Wales, Australia