1. Centre for Clinical Epidemiology and Biostatistics (CCEB), The School of Medicine and Public Health, Faculty of Health, The University of Newcastle, Newcastle, NSW 2008, Australia
2. The School of Public Health and Community Medicine, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
3. Biostatistics, School of Medicine and Public Health, The University of Newcastle, Newcastle, NSW 2008, Australia
4. Research and Education Department, ASPETAR-Qatar Orthopaedic and Sports Medicine Hospital, P.O. Box 29992, Doha, Qatar