title: Crystal methamphetamine and initiation of injection drug use among street-involved youth in a Canadian setting.
abstract: BACKGROUND
  Although injection drug use is known to result in a range of health-related harms, including transmission of HIV and fatal overdose, little is known about the possible role of synthetic drugs in injection initiation. We sought to determine the effect of crystal methamphetamine use on risk of injection initiation among street-involved youth in a Canadian setting.
  
  
  METHODS
  We used Cox regression analyses to identify predictors of injection initiation among injection-naive street-involved youth enrolled in the At-Risk Youth Study, a prospective cohort study of street-involved youth in Vancouver, British Columbia. Data on circumstances of first injection were also obtained.
  
  
  RESULTS
  Between October 2005 and November 2010, a total of 395 drug injection-naive, street-involved youth provided 1434 observations, with 64 (16.2%) participants initiating injection drug use during the follow-up period, for a cumulative incidence of 21.7 (95% confidence interval [CI] 1.7-41.7) per 100 person-years. In multivariable analysis, recent noninjection use of crystal methamphetamine was positively associated with subsequent injection initiation (adjusted hazard ratio 1.93, 95% CI 1.31-2.85). The drug of first injection was most commonly reported as crystal methamphetamine (14/31 [45%]).
  
  
  CONCLUSIONS
  Noninjection use of crystal methamphetamine predicted subsequent injection initiation, and crystal methamphetamine was the most commonly used drug at the time of first injection. Evidence-based strategies to prevent transition to injection drug use among crystal methamphetamine users are urgently needed.
authors.forename: Dan
authors.initials: D
authors.lastname: Werb
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.forename: Jane
authors.initials: J
authors.lastname: Buxton
authors.forename: Jeannie
authors.initials: J
authors.lastname: Shoveller
authors.forename: Chris
authors.initials: C
authors.lastname: Richardson
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D062787:Drug Overdose / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D018453:Homeless Youth / Q000706:statistics & numerical data*; D006801:Humans; D013287:Illicit Drugs / Q000506:poisoning*; D015994:Incidence; D035846:Law Enforcement; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000506:poisoning*; D011446:Prospective Studies; D015819:Substance Abuse, Intravenous / Q000453:epidemiology* / Q000517:prevention & control; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D008694:Methamphetamine