title: Reducing bias in prospective observational studies of drug users: the need for upstream and downstream approaches.
authors.affiliation: Kirby Institute for Infection and Immunity, Faculty of Medicine, UNSW Australia, Sydney, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Maher
authors.affiliation: University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Page
mesh_terms: D015982:Bias; D015331:Cohort Studies; D055030:Drug Users; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D015819:Substance Abuse, Intravenous
keywords: Bias; cohort; initiation; injection drug use; loss to follow-up.