title: The effect of a needle exchange program on numbers of discarded needles: a 2-year follow-up.
abstract: OBJECTIVE
  This study estimates the quantity and geographic distribution of discarded needles on the streets of Baltimore, Md, during the 2 years after a needle exchange program opened.
  
  
  METHODS
  Thirty-two city blocks were randomly sampled. Counts were taken of the number of syringes, drug vials, and bottles before the needle exchange program opened and then at 6 periodic intervals for 2 years after the program opened. Nonparametric and generalized estimating equation models were used to examine change over time.
  
  
  RESULTS
  Two years after the needle exchange program opened, there was a significant decline in the overall quantity of discarded needles relative to that of drug vials and bottles (background trash). The block mean of number of needles per 100 trash items was 2.42 before the program opened and 1.30 2 years later (mean within-block change = -0.028, P < .05). There was no difference in the number of discarded needles by distance from the program site.
  
  
  CONCLUSIONS
  These data suggest that this needle exchange program did not increase the number of distribution of discarded needles.
authors.affiliation: Department of Epidemiology, Johns Hopkins School of Hygiene and Public Health, Baltimore, Md. 21205, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Doherty
authors.forename: B
authors.initials: B
authors.lastname: Junge
authors.forename: P
authors.initials: P
authors.lastname: Rathouz
authors.forename: R S
authors.initials: RS
authors.lastname: Garfein
authors.forename: E
authors.initials: E
authors.lastname: Riley
authors.forename: D
authors.initials: D
authors.lastname: Vlahov
mesh_terms: D015142:Baltimore; D003625:Data Collection; D005500:Follow-Up Studies; D006801:Humans; D018671:Needle-Exchange Programs / Q000706:statistics & numerical data*; D011897:Random Allocation; D012037:Refuse Disposal / Q000706:statistics & numerical data*; D012044:Regression Analysis; D013997:Time Factors