title: The Authors Respond.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran, mansournia_ma@yahoo.com Departments of Epidemiology and Biostatistics, Harvard School of Public Health, Boston, MA, Harvard-MIT Division of Health Sciences and Technology, Boston, MA.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mansournia
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Hernán