Structural factors associated with an increased risk of HIV and sexually transmitted infection transmission among street-involved youth.(Research article)(human immunodeficiency virus)(Report)

Authors: Brandon DL Marshall [1,2]; Thomas Kerr [1,3]; Jean A Shoveller [2]; Julio SG Montaner [1,3]; Evan Wood (corresponding author) [1,3]

Background

Structural factors, defined as the economic, social, policy, and organizational environments that "structure" the context in which risk production occurs [1], are increasingly recognised as important determinants in the acquisition, transmission, and prevalence of HIV disease [2]. In recent years, extensive research has examined the structural factors that produce and re-produce HIV risk among high prevalence populations, including injection drug users (IDU) and sex workers [3, 4]. Homeless and street-involved adolescents have also been recognised as a marginalised population with unique exposures to structural environments that increase the likelihood of sustained and elevated disease burden; however, these factors remain poorly understood [5].

In Canada and the United States, it is estimated that between 4 and 7 percent of youth between the ages of 14 and 26 are absolutely, periodically, or temporarily without access to safe and stable shelter [6, 7]. Homeless and street-involved youth are known to be at a significantly increased risk for a wide range of adverse health outcomes [8]. Of considerable public health concern is the high prevalence of HIV and sexually transmitted infections (STIs) among these populations. In urban centres in Canada, the prevalence of HIV among street-involved youth is approximately 2 percent [9, 10], while the prevalence of Chlamydia has been estimated to be between 7 and 11 percent [11, 12]. Similar rates have been observed in the United States [13, 14].

Street-involved youth engage in a greater number of sexual risk behaviours than their non-homeless peers [15]. The vast majority is sexually active, and among those who do engage in sexual intercourse, inconsistent condom use is common [16, 17]. Street-involved youth are also more likely to have multiple and concurrent sex partners [18, 19]. Of further concern is that approximately one quarter of street youth have engaged in survival sex (i.e., sex in exchange for money, shelter, food or drugs) [20]. Among youth who are coerced or manipulated into survival sex, sexual victimization and abuse are common [21].

Research that has attempted to elucidate the underlying reasons for increased engagement in sexual risk behaviour among street-involved youth has continued to rely predominantly on individual level risk factor analyses [22]. However, a growing body of literature has demonstrated that a focus on individual level characteristics (e.g., childhood abuse, depression, knowledge) fails to acknowledge the social structural factors that shape and determine the context in which sexual risk behaviour takes place [3, 23]. Furthermore, it is increasingly recognised that structural factors, including economic inequities, laws, policies, and systemic discrimination, are better overall predictors of population level HIV and STI prevalence [24]. Given these methodological challenges and concerns, we sought to determine whether structural factors are associated with increased engagement in sexual risk behaviour among a community-recruited cohort of street-involved youth.

Methods

The At Risk Youth Study (ARYS) is a prospective cohort of homeless and street-involved youth in Vancouver, Canada that has been described in detail previously [25]. Briefly, participants were recruited through snowball sampling and extensive street-based outreach. Persons were eligible for the study if they were 14 to 26 years of age, had used illicit drugs other than or in addition to marijuana in the past 30 days, and provided informed consent. At baseline and semi-annually, participants complete an interviewer-administered questionnaire and provide blood samples for HIV and hepatitis C (HCV) serology. The questionnaire elicits demographic data and information regarding injection and non-injection drug use, HIV risk behaviours, addiction treatment experience, encounters with police and security guards, health service utilization, and sexual activity. All participants receive a monetary stipend of $20 CDN after each visit. The study has been approved by the University of British Columbia/Providence Health Care Research Ethics Board.

All participants who completed a baseline survey between September 2005 and October 2006 were included in this study. Since data from just one follow-up period was available at the time of study conception, only information collected at baseline was included in these analyses. We examined as our primary outcomes two sexual risk behaviours that together play key roles in determining the sexual transmission of HIV and STIs: 1) number of sexual partners, and 2) condom use during vaginal and anal intercourse. Participants were asked to report how many different male and female partners they had engaged in sexual activities with in the past 6 months, excluding those with whom they had engaged in sex for money, shelter, food, or drugs (i.e., sex trade work). Specifically, the total number of partners was obtained by adding responses to the questions: "Could you give me a precise number of male/female partners you had in the past 6 months?". Participants could report any set of positive integer values; thus, the variable was coded as continuous in bivariate and multivariate analyses. The resulting distribution was positively skewed, with a median of 1.0 (interquartile range: 0-3), a mean of 3.2 (standard deviation: 5.6), and a range of 0-55. For both same and opposite sex partnerships, participants were also asked to report how often a condom was used during vaginal and/or anal …