title: Predictors of needle exchange program utilization during its implementation and expansion in Tijuana, Mexico.
abstract: OBJECTIVE
  Until the early 2000s, there was only one needle exchange program (NEP) offered in Mexico. In 2004, the second Mexican NEP opened in Tijuana, but its utilization has not been studied. We studied predictors of initiating NEP during its early expansion in Tijuana, Mexico.
  
  
  METHODS
  From April 2006 to April 2007, people who inject drugs (PWID) residing in Tijuana who had injected within the last month were recruited using respondent-driven sampling. Weighted Poisson regression incorporating generalized estimating equations was used to identify predictors of initiating NEP, while accounting for correlation between recruiter and recruits.
  
  
  RESULTS
  NEP uptake increased from 20% at baseline to 59% after 6 months. Among a subsample of PWID not accessing NEP at baseline (n = 480), 83% were male and median age was 37 years (Interquartile Range: 32-43). At baseline, 4.4% were HIV-infected and 5.9% had syphilis titers >1:8. In multivariate models, factors associated with NEP initiation (p < .05) were attending shooting galleries (Adjusted Relative Risk [ARR]: 1.54); arrest for track-marks (ARR: 1.38); having a family member that ever used drugs (ARR: 1.37); and having a larger PWID network (ARR: 1.01 per 10 persons). NEP initiation was inversely associated with obtaining syringes at pharmacies (ARR: .56); earning >2500 pesos/month (ARR: .66); and reporting needle sharing (ARR: .71).
  
  
  CONCLUSIONS
  Uptake of NEP expansion in Tijuana was vigorous among PWID. We identified a range of factors that influenced the likelihood of NEP initiation, including police interaction. These findings have important implications for the scale-up of NEP in Mexico.
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.|Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Smith
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.
authors.forename: Dan
authors.initials: D
authors.lastname: Werb
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.
authors.forename: Daniela
authors.initials: D
authors.lastname: Abramovitz
authors.affiliation: Centro Nacional parala Prevencion y Control del VIH/SIDA e ITS (CENSIDA), Mexico City, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Magis-Rodriguez
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.
authors.forename: Alicia
authors.initials: A
authors.lastname: Vera
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Patterson
authors.affiliation: Division of Global Public Health, Department of Medicine, University of California, San Diego.
authors.forename: Steffanie A
authors.initials: SA
authors.lastname: Strathdee
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D018671:Needle-Exchange Programs / Q000706:statistics & numerical data*; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D016495:Police / Q000706:statistics & numerical data; D015819:Substance Abuse, Intravenous / Q000517:prevention & control*