School of Medicine and Public Health, Hunter Medical Research Institute, University of Newcastle, Newcastle, New South Wales, Australia. Hunter New England Population Health, Wallsend, New South Wales, Australia. Centre for Pain, Health and Lifestyle, Ourimbah, New South Wales, Australia. Department of Health Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, The Netherlands. Department of Health Sciences, Faculty of Science, Vrije Universiteit Amsterdam, MOVE research institute Amsterdam, Amsterdam, The Netherlands. School of Public Health, University of Sydney, Camperdown, New South Wales, Australia. Neuroscience Research Australia (NeuRA), Randwick, New South Wales, Australia. Centre for Statistics in Medicine, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK. Outpatient Services, John Hunter Hospital, Hunter New England Local Health District, New Lambton, New South Wales, Australia. NSW Office of Preventive Health, Liverpool Hospital, South West Sydney Local Health District, Liverpool, New South Wales, Australia.