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1 Department of Epidemiology and Department of Statistics, University of California, Los Angeles, CA, USA.
2 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, PO box 14155-6446, Tehran, Iran mansournia_ma@yahoo.com.
3 Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
1 Department of Epidemiology and Department of Statistics, University of California, Los Angeles, CA, USA.
2 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, PO box 14155-6446, Tehran, Iran mansournia_ma@yahoo.com.
3 Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.