1 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran mansournia_ma@yahoo.com nazemipour.m@iums.ac.ir.
2 Sports Medicine Research Center, Tehran University of Medical Sciences, Neuroscience Institute, Tehran, Iran.
3 Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
4 National Institute for Health Research Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK.
5 Department of Public Health, Section for Sports Science, Aarhus University, Aarhus, Denmark.
6 Research Unit for General Practice, Aarhus, Denmark.
7 Psychosocial Health Research Institute, Iran University of Medical Sciences, Tehran, Iran mansournia_ma@yahoo.com nazemipour.m@iums.ac.ir.
8 Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK.
9 Division of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, California, USA.
10 ScHARR, University of Sheffield, Sheffield, UK.