title: Reply.
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Kuniholm
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
authors.forename: Kenrad E
authors.initials: KE
authors.lastname: Nelson