Spatial access to syringe exchange programs and pharmacies selling over-the-counter syringes as predictors of drug injectors' use of sterile syringes

Objectives: We examined relationships of spatial access to syringe exchange programs (SEPs) and pharmacies selling over-the-counter (OTC) syringes with New York City drug injectors' harm reduction practices. Methods: Each year from 1995 to 2006, we measured the percentage of 42 city health districts' surface area that was within 1 mile of an SEP or OTC pharmacy. We applied hierarchical generalized linear models to investigate relationships between these exposures and the odds that injectors (n=4003) used a sterile syringe for at least 75% of injections in the past 6 months. Results: A 1-unit increase in the natural log of the percentage of a district's surface area within a mile of an SEP in 1995 was associated with a 26% increase in the odds of injecting with a sterile syringe; a 1-unit increase in this exposure over time increased these odds 23%. A 1-unit increase in the natural log of OTC pharmacy access improved these odds 15%. Conclusions: Greater spatial access to SEPs and OTC pharmacies improved injectors' capacity to engage in harm reduction practices that reduce HIV and HCV transmission.