Social Networks, Geography, and Syringe Sharing Among Young People Who Inject Drugs

Introduction: Injection drug use is a risk factor for HIV and hepatitis C (HCV) infections. In recent decades there has been a significant shift in the demographic profile of people who inject drugs (PWID), with initiates being increasingly likely to be suburban and non-Hispanic white. Young white suburban PWID have low rates of HIV and HCV infection, but frequently engage in behavior that places them at risk. This study examines social network and geographic characteristics associated with sharing syringes among young PWID.

Methods: We conducted a cross-sectional personal network and geographic study of 164 young PWID, collecting information on drug-using, sexual, and social support network members. Most participants were registered members of a large Chicago Syringe Exchange Program (SEP) with 5 locations in major outdoor heroin and cocaine markets that attract both urban and suburban drug users. Others were enrolled through active recruitment and flyers.  To be eligible, participants had to be 18 to 30 years old and have injected drugs in the past 30 days.

Results: About one third (37%) of participants reported suburban residence(s), 36% reported urban residence(s), and 27% reported both suburban and urban residences (“crossover”) in the past year. Among participants who injected with others in the past 6 months (n=145), 34% reported sharing a syringe with a network member. Participants who reported “crossover” residences were significantly more likely to share syringes (53% vs. 30% suburban and 22% urban; chi-square=9.37, p=.009).  HCV-negative participants were significantly less likely to share syringes (24% vs. 64% positive and 46% untested; chi-square=12.50, p=.002). After adjusting for network characteristics that influence syringe sharing, respondent characteristics associated with increased likelihood of sharing included female injecting with male partner (OR=3.75, 95% CI:1.45-9.68), “crossover” vs. suburban residence (OR=3.94, 95% CI: 1.44-10.78), and unknown HCV status vs. HCV negative (OR=5.53, 95% CI: 1.92-15.87). Network characteristics associated with syringe sharing included sex partner status (OR=3.99, 95% CI: 1.11-14.34), male partner of female respondent (OR=5.32, 95% CI: 1.38-20.46), sharing a residence (OR=7.17, 95% CI: 2.08-24.66), and “crossover” vs. urban residence (OR=5.60, 95% CI: 1.24-25.23).

Conclusions: Further research is needed to understand the risk behavior of young PWID who move from the suburbs into the city. Interventions need to address syringe sharing in sexual relationships, and other close and cross-gender relationships.