1 Hunter New England Population Health, Wallsend, New South Wales.
2 School of Medicine and Public Health, University of Newcastle, New South Wales.
3 Hunter Medical Research Institute, New Lambton Heights, New South Wales.
4 Priority Research Centre for Health Behaviour, University of Newcastle, New South Wales.
5 Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, United Kingdom.