Studying urban-suburban bridging groups and their social networks in metropolitan Chicago among persons who inject drugs

Background: Young persons who inject drugs (PWID) are increasingly from suburban communities and predominantly non-Hispanic (NH) white. The impact of this demographic and geographic shift on HIV and hepatitis C (HCV) risk has not been adequately studied.

Methods: We conducted a cross-sectional personal network (egocentric) and geographic study of 164 young PWID (egos) and their drug-using, sexual, and support network members (alters) in metropolitan Chicago, Illinois. We recruited at Community Outreach Intervention Projects (COIP) syringe exchange program sites located in urban neighborhoods, using COIP’s Indigenous Leader Outreach Model where former drug users recruit active PWID.

Results: We enrolled 164 young PWID (median age=26) who were mostly male (65%), non-Hispanic white (71%) heroin (99%) injectors. Self-reported prevalence of HCV was 13% and HIV <1%. Most participants reported multiple residences in the past year. Compared to the participants, the overall drug use network was slightly older (mean=29.7) and similarly likely to be non-Hispanic white (69%). In multivariable models that controlled for demographic, risk behavior and network characteristics: (1) residing in both urban and suburban areas (crossover) was associated with syringe sharing; (2) homelessness was significantly associated with core network size, and (3) homelessness and HCV-positive status were associated with increasing number of HCV-positive persons in the core network.

Conclusions: We identified geographic mobility between suburban and urban locations as a significant risk factor associated with syringe sharing in a sample of young PWID. Further research is needed to understand the role of geographic factors promoting higher risk among these crossover PWID.