High-Risk Geographic Mobility Patterns among Young Urban and Suburban Persons who Inject Drugs and their Injection Network Members

Abstract

Young people in the USA who inject drugs, particularly those at a risk of residence instability, experience the highest incidence of hepatitis C (HCV) infections. This study examined associations between geographic mobility patterns and sociodemographic, behavioral, and social network characteristics of 164 young (ages 18-30) persons who inject drugs (PWID). We identified a potential bridge sub-population who reported residence in both urban and suburban areas in the past year (crossover transients) and higher-risk behaviors (receptive syringe sharing, multiple sex partners) compared to their residentially localized counterparts. Because they link suburban and urban networks, crossover transients may facilitate transmission of HIV and HCV between higher and lower prevalence areas. Interventions should address risk associated with residential instability, particularly among PWID who travel between urban and suburban areas.

Social Networks of Substance-Using Populations: Key Issues and Promising New Approaches for HIV

“…However, relocating to neighborhoods with better social and economic conditions was associated with smaller networks of substance users and more turnover out of substance-using networks. Work in Chicago with young PWID found that crossover transience between urban and suburban places was a significant risk factor for syringe sharing and multiple sex partners, but that transience was often tied to homelessness [35,36]. Importantly, this study suggests that this movement served as a spatial bridge for HIV between higher prevalence and lower prevalence areas [35,36].…”

“…New research supports the importance of network size [21], structure [22], bridging (i.e., ties connecting different groups) [23], clustering (i.e., nodes grouping together) [24], multiplexity (i.e., ties with multiple social connections, such as a sexual and drug use connection) [25][26][27], and social support and capital [28][29][30] for HIV risk behavior, transmission, viral suppression, HIV disclosure, and ART initiation. This work entails an expanded focus on populations that have historically received less attention, including research on the networks of non-injecting drug users [31,32], substance users in suburban and rural areas [22,31,[33][34][35][36], and the role of networks in newly emerging HIV outbreaks, both domestically [37][38][39] and globally [3,[40][41][42][43]. Of particular note, recent research has evolved to utilize new network concepts and to more fully account for risk environment factors that shape health.…”

“…Importantly, neighborhoods and venues are essential to understanding HIV transmission dynamics because they serve as locations where networks converge. At the same time, we know that networks often transcend geographic space, which has implications for HIV transmission and public health efforts: studies show cross-border PWID networks between San Diego and Tijuana [62,67] and suburban and urban networks near Chicago [35,36].…”

“…Increasingly, researchers have combined place-based methods with network research in ways that have illustrated the geographic and sociospatial dynamics underlying drug userelated harms and HIV. For example, recent work has shown the impact of neighborhood context and movement across neighborhoods on network composition, stability, and bridging and how these shifts may increase vulnerability to HIV [35,36,76,77]. Among substance-using individuals relocating from public housing complexes in Atlanta, both old and new neighborhood characteristics shaped networks: on the one hand, prior residence in violent neighborhoods predicted future illicit drug-using networks [77].…”

“…Work in Chicago with young PWID found that crossover transience between urban and suburban places was a significant risk factor for syringe sharing and multiple sex partners, but that transience was often tied to homelessness [35,36]. Importantly, this study suggests that this movement served as a spatial bridge for HIV between higher prevalence and lower prevalence areas [35,36]. Collectively, this research highlights the need to better understand how movement across geographic space shapes networks in ways that may increase or reduce vulnerability to substance use and HIV.…”