Factors associated with buying and selling syringes among injection drug users in a setting of one of North America's largest syringe exchange programs

We performed analyses of syringe buying and syringe selling among Vancouver injection drug users, recruited from May 1996 and followed up between November 2002 and August 2003, in the context of one of North America's largest syringe exchange programs (SEPs). An interviewer-administered questionnaire, approximately 45 minutes in duration, was used to collect information regarding risk factors for HIV infection and sources of sterile syringes. Seventy participants (15%) reported syringe selling and 122 (26%) reported syringe buying. Syringe sellers were more likely to be female, reside in unstable housing, need help injecting, and have visited the SEP at least once weekly. Syringe buyers were more likely to need help injecting, have difficulty finding new syringes, have binged on drugs, and have visited the SEP at least once weekly. Syringe buying most frequently occurred when the SEP was closed.