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Health Place. Author manuscript; available in PMC 2010 September 1.
Published in final edited form as:
PMCID: PMC2673329

Homelessness and Unstable Housing Associated with an Increased Risk of HIV and STI Transmission among Street-Involved Youth


The role that environmental factors play in driving HIV and STI transmission risk among street-involved youth has not been well examined. We examined factors associated with number of sex partners using quasi-Poisson regression and consistent condom use using logistic regression among participants enroled in the At Risk Youth Study. Among 529 participants, 253 (47.8%) reported multiple partners while only 127 (24.0%) reported consistent condom use in the past six months. Homelessness was inversely associated with consistent condom use (adjusted odds ratio [aOR]=0.47, p=0.008), while unstable housing was positively associated with greater numbers of sex partners (adjusted incidence rate ratio [aIRR]=1.44, p=0.010). These findings indicate the need for interventions which modify environmental factors that drive risk among young street-involved populations.

Keywords: Adolescent, Homeless Youth, Sexual Behavior, Substance Use, HIV


Populations of homeless and street-involved youth are increasing in many North American settings (Public Health Agency of Canada, 2006b). In Canada, it has been estimated that there are upwards of 150,000 street-involved youth (DeMatteo et al., 1999). Although street youth are known to be at increased risk for a host of negative health outcomes, some of the most commonly reported concerns among this population are sexual and reproductive health issues (Frankish et al., 2005; Feldmann and Middleman, 2003). Many studies of street-involved youth have documented drastically elevated rates of HIV, sexually transmitted infections (STIs), and other blood borne diseases, including hepatitis B (HBV) and hepatitis C (HCV) (Roy et al., 2001; Roy et al., 1999; Roy et al., 2003b; Pfeifer and Oliver, 1997; Allen et al., 1994; Noell et al., 2001a). The prevalence of HIV among street-involved youth in Montreal (Roy et al., 2000) and Toronto (DeMatteo et al., 1999) has been estimated to be approximately 2%, while some studies in the United States have documented rates over 8% (Shalwitz et al., 1990; Rew et al., 2002; Pfeifer and Oliver, 1997). A recent report by the Public Health Agency of Canada indicated that the prevalence of Chlamydia trachomatis (CT) among Canadian street youth is at least ten times that of the general adolescent populations (Public Health Agency of Canada, 2006a), while cross-sectional studies have documented CT rates between 6.6% and 8.6% (Haley et al., 2002; Shields et al., 2004).

To explain the elevated rates of HIV and STIs among this population, epidemiological studies have described a range of sexual risk behaviours. The vast majority of street-involved youth are sexually active, among whom inconsistent condom use (i.e., not always using condoms with all sexual partners) is reported by 50% to 80% (Halcon and Lifson, 2004; Moon et al., 2001; de Carvalho et al., 2006; Milburn et al., 2006; Kissin et al., 2007). Street-involved youth are also likely to report multiple recent sexual partnerships. For example, the median number of sex partners in the past six months has been found to vary between 1 and 6 (Moon et al., 2000; Zimet et al., 1995; Montgomery et al., 2002; Zanetta et al., 1999). Furthermore, studies in Canada and the US suggest that approximately one quarter of street-involved youth have ever exchanged sex for money, drugs, shelter, or gifts (Kipke et al., 1995; Greene et al., 1999; Weber et al., 2002).

Along with sociodemographic factors such as age, gender, and ethnicity, commonly reported correlates of sexual risk behaviour among street-involved youth include: childhood sexual abuse (Stoltz et al., 2007; Noell et al., 2001b); depression (Rohde et al., 2001); relationship status (Evans et al., 2003; Coady et al., 2007); sexual decision making (Harvey et al., 2003); and a range of drug-related factors, including injection drug use (Haley et al., 2004; Gleghorn et al., 1998; Solorio et al., 2008). While the majority of studies have focused primarily on the individual, social and drug-related factors that predict engagement in sexual risk behaviour, less is known about the environmental influences that may impact the risk factors for HIV and STI transmission among youth. However, a growing body of literature has documented the association between homelessness and HIV transmission among adults and the link between housing status and health outcomes of people living with HIV (Wolitski et al., 2007). For example, unstable housing has been associated with elevated HIV incidence among injection drug users (Corneil et al., 2006), while a dose-response relationship between number of residences lived in and the likelihood of unprotected intercourse has been observed among incarcerated women at high risk for HIV (Weir et al., 2007). Furthermore, female drug users who remain in unstable housing environments are less likely to reduce HIV-related risk behaviours as compared to individuals who become stably housed (Elifson et al., 2007). Homelessness and residential instability have also been associated with exposure to sexual and drug-related HIV risk among young men who have sex with men (MSM) (Kipke et al., 2007; Clatts et al., 2005).

To date, research examining the impact of homelessness on HIV risk behaviour among street-involved youth is equivocal. In a multi-site study of high risk adolescents conducted in the US, homelessness was found to be associated with HIV positivity, but only among males (Huba et al., 2000). A prospective study of newly homeless youth observed no significant association between future housing stability and sexual risk behaviour (Rosenthal et al., 2007); however, several studies have found that duration of homelessness is a predictor of behavioral outcomes associated with sexual health (Ennett et al., 1999; Rew et al., 2008; Milburn et al., 2006). There exists a lack of knowledge regarding how specific physical conditions associated with these periods of homelessness may influence sexual risk behaviour. Given that street-involved youth reside in a wide variety of settings (e.g., shelters, hostels, vehicles, parks, and other public spaces) (Greenblatt and Robertson, 1993; Daly, 1996), elucidating how specific environments may promote behaviours which drive the transmission of HIV and STIs is important to furthering our understanding of the multi-level factors that determine population level disease burden. Therefore, we conducted this study to determine if environmental factors, independent of individual level characteristics, predict engagement in sexual risk behaviour among a sample of street-involved youth.


The At Risk Youth Study (ARYS) is an ongoing prospective cohort of homeless and street-involved youth in Vancouver, Canada. The study has been described in detail previously (Wood et al., 2006). Briefly, the study consists of a convenience sample recruited through extensive street-based outreach and snowball sampling in which street youth were encouraged to recruit their peers. Outreach teams consisting of street nurses and study staff worked in close collaboration with local youth service organizations and agencies to refine the recruitment process and to ensure that specific hidden subpopulations (e.g., street youth who identify as lesbian, gay, bisexual, transsexual, or transgendered [LGBTT]) were represented. Furthermore, these organizations were encouraged to refer eligible youth to the study. Although these recruitment techniques are inferior to a random probability-based sampling, extensive efforts were taken to maximize the representativeness of the sample. For example, outreach was systematically conducted in a range of city neighbourhoods in areas where street youth are known to congregate, including shelters, youth services, and on the street. Outreach was also conducted at different times during the day and at night.

The term “street-involved youth” has been defined as an adolescent who spends a substantial amount of time on the street or is heavily engaged in the street economy (Marlatt, 2002), and may include youth who are absolutely, periodically, or at imminent risk of being homeless (Daly, 1996). As in previous studies of street-involved youth (Roy et al., 2003a; DeMatteo et al., 1999), housing status was not included as an eligibility criterion in order to capture as much as possible the diverse spectrum of street youth. Specific eligibility criteria included being between the age of 14 and 26 years of age at baseline, illicit drug use other than or in addition to marijuana in the past 30 days, and the provision of informed consent. At baseline and semi-annually, participants complete an interviewer-administered questionnaire and provide blood samples for HIV and hepatitis C (HCV) serology. 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 were recruited and completed a baseline survey between September 1, 2005 and October 31, 2006 were included in this cross-sectional analysis. The primary outcomes of interest in this study were number of sexual partners in the past 6 months and condom use during vaginal and anal intercourse during the past 6 months. Participants were asked to report how many male and female partners they had engaged in sexual activities with, excluding those with whom they had engaged in sex for money, drugs, shelter, or gifts. Since sex work is known to be associated with a profile of sexual risk behaviour distinct from that in the context of voluntary sex among both male and female street youth (Haley et al., 2004; Weber et al., 2004), we chose to omit this activity from our analyses. For both same and opposite sex partnerships, participants were also asked to report how often a condom was used during vaginal and anal intercourse. Possible responses included: always, regularly, occasionally, and never. To be consistent with previous studies of condom use among street-involved youth (de Carvalho et al., 2006; Moon et al., 2001), this variable was dichotomized into “consistent” (i.e., always) and “inconsistent” (i.e., regularly, occasionally, or never) condom use. Participants who reported more than one type of sexual activity in the past six months and who reported discordant condom use patterns were coded as inconsistent condom users.

The primary explanatory variable of interest in this study was current place of residence. For analytical purposes, we created a categorical variable with the following three levels: 1) stably housed – living in an apartment, house or single room occupancy hotel (SRO); 2) unstably housed – living in a shelter or hostel; and 3) homeless – living on the street or having no fixed address (NFA). Other independent variables included a range of sociodemographic, individual level, drug-related, and social factors, and were chosen based on their known or a priori hypothesized relationship with both housing status and one or both of the sexual risk behaviours listed above. Sociodemographic variables that were examined included: age (per year older), sex (female vs. male), Aboriginal ethnicity (yes vs. no) and sexual orientation (LGBTT vs. heterosexual). Other individual level factors that were examined included engaging in anal intercourse in the past six months (yes vs. no), sexual abuse (yes vs. no), depression, and self-efficacy for limiting HIV risk behaviours (LHRB). Sexual abuse was defined as answering “yes” to the question, “Have you ever been sexually abused?”, while the latter two variables were defined using validated, published scales. The Center for Epidemiologic Studies Depression Scale (CES-D) is designed to measure current levels of depressive symptoms and has been shown to have high levels of internal consistency and reliability among groups of adolescents (Radloff, 1977; Rushton et al., 2002). The presence of depressive symptoms was evaluated using a well-defined cut-off (CES-D ≥ 16 [yes] versus CES-D < 16 [no]). The self-efficacy for LHRB Scale is a validated instrument found to have high levels of consistency among at-risk youth (Smith et al., 1996; Kang et al., 2004). Self-efficacy refers to the belief in one’s capability of performing actions to attain certain goals (Bandura, 1986); therefore, the LHRB Scale consists of questions that require a respondent to record how sure they are that they could perform sexual and injection-related risk reduction behaviours, such as talking about safe sex with a partner, using a condom correctly during sex, and refusing to share needles with friends. Responses were dichotomized into “high” versus “low” self-efficacy for LHRB based on their value with respect to the sample median. Social and drug-related factors that were examined included: relationship status (single or casually dating vs. regular partner or married), drug dealing (yes vs. no), alcohol dependence (yes vs. no), crack use (yes vs. no), cocaine use (yes vs. no), heroin use (yes vs. no), crystal methamphetamine use (yes vs. no), injection drug use (yes vs. no), and sharing syringes (yes vs. no). Alcohol dependence was measured using the Perceived-Benefit-of-Drinking Scale (PBDS), a 5-item true/false validated instrument that is used to assess drinking behaviours among adolescents (Petchers and Singer, 1987; Petchers et al., 1988). A standard a priori defined cut-off of three or higher was used to define alcohol dependence. All other drug-use variables refer to behaviours occurring in the past six months: cocaine, heroin, and crystal methamphetamine use refer to both injection and inhalation routes of consumption. To be consistent with our previous work, syringe sharing was defined as lending or borrowing a used syringe in the past six months (Kerr et al., 2005). Since sexual risk behaviours are known to be interdependent (Aral, 2004), each dependent variable was included as a potential explanatory variable when not used as the primary dependent variable of interest.

Initially, we examined bivariate associations between the individual level, social, drug-related and environmental variables and each sexual risk behaviour outcome. To analyse the sexual partnership data, a Poisson-type regression was used to estimate the unadjusted incidence rate ratio (IRR) and 95% confidence intervals (95% CI) associated with each independent variable. The distribution of recent sex partners was highly skewed; therefore, in order to account for overdispersion, we used a log-linear quasi-Poisson regression. This approach relaxes the assumption that the variance of the underlying distribution is equal to the mean by allowing the variance to be modeled as a linear function of the mean (McCullagh and Nelder, 1999; Ver Hoef and Boveng, 2007). To analyse the bivariate associations with consistent condom use, dichotomous and categorical variables were examined using the Pearson χ2 test.

Since the objective of this study was to determine whether environmental conditions, independent of established sociodemographic and individual level factors, are associated with sexual risk behaviour, we fit a series of confounding models based on an approach described by Rothman and Greenland (Rothman and Greenland, 1998; Maldonado and Greenland, 1993). For a variable to be considered a confounder in the relationship between place of residence and sexual risk behaviour, it must be associated with both the behaviour and with housing status. Therefore, we conducted initial bivariate screenings based on a conservative p-value of 0.20 to determine which explanatory variables were associated with the outcome and thus may be potential confounders. We then used these variables to create two multivariate “full” models. These models were then subjected to a manual stepwise approach to select significant confounders. Starting with the “full” models, variables that did not alter the relative change in the coefficient of the primary variable of interest by more than 10% were removed in a sequential fashion. Since the primary variable of interest was categorical with two levels, variables were considered significant confounders if their removal altered one or both of the coefficients by more than 10%. This technique has been described and used successfully by several authors (Lima et al., 2007; Lima and Kopec, 2005; Maldonado and Greenland, 1993). To account for the well-established confounding effects of age, sex, ethnicity, and sexual orientation, these variables were forced into the “full” models and were not subjected to the stepwise procedure. All statistical modelling was conducted using S-PLUS software version 8.0. All reported p-values are two-sided.


A total of 529 participants completed a baseline interview between September 2005 and October 2006. As shown in Table 1, the mean age was 21.9 (standard deviation [SD] = 2.8), 159 (30.1%) were female, 127 (24.0%) were of Aboriginal ethnicity, and 69 (13.0%) self-identified as non-heterosexual. The sociodemographic characteristics of this sample are similar to a Vancouver street youth study conducted in 2003 in which the mean age was 22.2 (SD = 3.1), 28.2% of participants were female, and 24.0% self-identified as Aboriginal (Martin et al., 2006). A national survey of urban street youth conducted in 2003 observed a mean age of 19.7 with a similar proportion of females (37.1%) but a higher proportion of Aboriginals (36.3%) (Public Health Agency of Canada, 2006b). Sexual activity in the past six months was reported by 415 (78.4%), of whom 253 (61.0%) reported multiple sex partners and 127 (30.6%) reported consistent condom use. The median number of sex partners in the past six months was 1 (interquartile range: 1 – 3; range: 0 – 55).

Table 1
Sociodemographic characteristics and sexual behaviours of street-involved youth in Vancouver, Canada (n = 529).

The results of the bivariate quasi-Poisson analyses are shown in Table 2. As a group, housing status was statistically significant (type 3 p-value < 0.001, 2 df). Additional pairwise comparisons revealed that living in a shelter or hostel (incidence rate ratio [IRR] = 1.65, 95% confidence interval [95% CI]: 1.12 – 2.43) was positively associated with greater numbers of sex partners, and living NFA or on the street was marginally significant (IRR = 1.40, 95% CI: 0.98 – 2.01). Other variables that that were positively associated with greater numbers of sex partner included: LGBTT orientation (IRR = 1.90, 95% CI: 1.37 – 2.63); being single or casually dating (IRR = 1.79, 95% CI: 1.19 – 2.69); low self-efficacy for LHRB (IRR = 1.55, 95% CI: 1.14 – 2.13); sometimes/occasionally using condoms (IRR = 1.52, 95% CI: 1.10 – 2.10); anal intercourse (IRR = 2.52, 95% CI: 1.83 – 3.48); sexual abuse (IRR = 1.67, 95% CI: 1.25 – 2.24); crack use (IRR = 1.45, 95% CI: 1.07 – 1.98); and cocaine use (IRR = 1.62, 95% CI: 1.20 – 2.19). Never using condoms (IRR = 0.56, 95% CI: 0.35 – 0.90) was inversely associated with number of sex partners. In a multivariate confounding model (see Table 2), housing status remained statistically significant (type 3 p-value < 0.001, df = 2), and additional pairwise comparisons revealed that living in a shelter or hostel was independently associated with greater numbers of sex partners (adjusted incidence rate ratio [aIRR] = 1.44, 95% CI: 1.09 – 1.90). Other factors that remained significant in the final model included: female gender (aIRR = 0.65, 95% CI: 0.49 – 0.87); Aboriginal ethnicity (aIRR = 0.75, 95% CI: 0.56 – 0.99); LGBTT orientation (aIRR = 1.75, 95% CI: 1.29 – 2.36); never using condoms (aIRR = 0.46, 95% CI: 0.31 – 0.68); anal intercourse (aIRR = 1.47, 95% CI: 1.13 – 1.91); sexual abuse (aIRR = 1.40, 95% CI: 1.09 – 1.79); crack use (aIRR = 1.46, 95% CI: 1.14 – 1.87); and cocaine use (aIRR = 1.39, 95% CI: 1.10 – 1.74).

Table 2
Factors associated with number of sex partners among a cohort of street-involved youth (n = 529).

The factors associated with consistent condom use in bivariate analyses are shown in Table 3. Overall, housing status was marginally significant (type 3 p-value = 0.077, 2 df). Additional pairwise comparisons revealed that living NFA or on the street (odds ratio [OR] = 0.56, 95% CI: 0.35 – 0.92) was significantly and inversely associated with consistent condom use. Other variables that were significantly (p < 0.05) associated with consistent condom use included: being single or casually dating ([OR] = 2.50, 95% CI: 1.46 – 4.30); LGBTT orientation (OR = 0.42, 95% CI: 0.20 – 0.90); and engaging in anal intercourse (OR = 0.41, 95% CI: 0.21 – 0.79). The results of the multivariate analysis are shown in Table 4. Housing status was independently associated with consistent condom use (type 3 p-value < 0.001, df = 2), and additional pairwise comparisons revealed that youth living NFA or on the street were significantly less likely to report consistent condom use (adjusted odds ratio [aOR] = 0.47, 95% CI: 0.27 – 0.82). In addition to housing status, being single or casually dating (aOR = 3.50, 95% CI: 1.89 – 6.50) and LGBTT orientation (aOR = 0.43, 95% CI: 0.19 – 0.98) were significantly associated with consistent condom use in the final confounding model.

Table 3
Factors associated with consistent condom use among a cohort of sexually active street-involved youth (n = 415).
Table 4
Multivariate logistic regression analysis of factors associated with consistent condom use among a cohort of sexually active street-involved youth (n = 415).

We also conducted a sensitivity analysis to determine if our model selection procedure significantly impacted the observed associations between housing status and sexual risk behaviours. Implementing an alternate model selection protocol whereby all variables significant in bivariate analyses (p < 0.10) were included did not significantly alter our results (data not shown). We also sought to examine whether the observed associations between LGBTT orientation and sexual risk behaviours were confounded by sex. An analysis of variance (ANOVA) revealed no significant difference between non-heterosexual men and non-heterosexual women with respect to the mean number of recent sexual partners (p = 0.068), while Fisher’s exact test revealed no significant difference in consistent condom use by sex when the sample was restricted to LGBTT participants (p = 0.720).


In the present study, we observed a high prevalence of multiple sexual partnerships and inconsistent condom use among a community-recruited cohort of street-involved adolescents. In multivariate analyses, we observed that housing status was a strong and independent correlate of both greater numbers of sex partners and inconsistent condom use, even after adjustment for sociodemographic, drug-related, and other individual level confounders. In particular, living in a shelter or hostel was positively associated with an elevated number of recent sex partners, while living NFA or on the street was inversely associated with consistent condom use. Since both the transmissibility of infection (determined in part by condom use) and the rate of sex partner change are key parameters that determine population-level HIV and STI incidence (Vickerman and Watts, 2003; May and Anderson, 1987), these findings indicate that precarious housing environments may act synergistically to increase sexual HIV and STI transmission among young street-involved populations.

We observed that specific housing and shelter environments appear to have distinct yet important impacts on sexual risk behaviours, independent of measured sociodemographic and individual level factors. Our finding that shelter and hostel-style housing conditions were correlated with an increased number of sexual partnerships is consistent with studies of other marginalized youth populations, including young MSM (Kipke et al., 2007), young IDU (Coady et al., 2007), and HIV positive adolescents (Eastwood and Birnbaum, 2007). Our findings suggest that conditions associated with the unique environment of shelter and hostel-based residences may play an important role in influencing behaviours that drive HIV and STI transmission, irrespective of individual level determinants such as depression, childhood trauma, and self-efficacy. For example, shelters and hostels in which a high turnover of clients is common may facilitate elevated rates of partner change among residents, particularly if cramped conditions necessitate the sharing of beds or sleeping quarters. Such environments may also facilitate discordant sexual mixing patterns that promote the transmission of HIV and other STIs (Aral et al., 2007); for example, young or recently homeless adolescents may be more likely to come in to contact with older, higher HIV/STI prevalence populations within shelter or hostel-based environments. Given that numerous epidemiological studies have shown how discordant mixing patterns can fuel the spread of HIV and STIs, particularly among low prevalence populations (Aral, 2002; Aral et al., 1999; Lee et al., 2003), future research should be conducted to examine more carefully the social-sexual networks of sheltered and unstably housed youth.

We also observed that over two thirds of sexually active youth reported inconsistent condom use with their recent sex partners, a prevalence similar to that observed in other North American and international settings (Kral et al., 1997; Solorio et al., 2006; de Carvalho et al., 2006; Kissin et al., 2007). Furthermore, those who were currently living NFA or on the street were twice as likely to report inconsistent condom use with their recent sexual partner(s). This effect remained significant even after accounting for potentially confounding factors such as relationship status, drug and injection-related risk behaviours, and a range of sociodemographic characteristics. Therefore, it is plausible that exposure to street environments, in particular living in deprived street-based conditions, may impact condom use patterns. While less is known regarding the influence of public and street-based environments on condom use, there exists an extensive literature describing how micro- and macro-environmental factors impact injection-related risk behaviour (Kerr et al., 2007). For example, public injection in which rushed, unsanitary injections are common has been linked to an array of HIV and health-related harms (Rhodes et al., 2006; Small et al., 2007; Clatts et al., 2001). Analogously, studies of MSM who have sex in public environments have observed low rates of condom use, which may be due to rushed encounters stemming from the fear of being harassed by police and homophobic individuals or groups (Somlai et al., 2001; French et al., 2000). Although youth who report living NFA or on the street likely have sex in a number of public, semi-public, and private environments, these results indicate that similar environmental mechanisms may play a role in structuring the context in which sexual risk behaviour and HIV/STI transmission among street-involved youth occurs.

Our results have a number of important implications for policy makers, health care workers, and youth organizations seeking to implements policies, laws, and programs that aim to reduce HIV and STI transmission among young street-involved populations. While historically youth sexual health interventions have privileged individual level determinism as the primary mechanism for enacting behaviour change, such programs often fail to result in sustained, population level health outcomes (Shoveller et al., 2006; Aral, 2002). Furthermore, it has been argued that such programs are unable to account for the social, environmental, and structural context in which HIV and STI risk produced (Rhodes et al., 2005; Frye et al., 2006; Shoveller et al., 2006; Kerrigan et al., 2006). Our results support these arguments and provide quantitative evidence that sexual risk behaviour is associated with and possibly perpetuated by environmental factors, including housing conditions. As such, we recommend that future policies and programs implement structural-environmental interventions within preexisting health-based infrastructures. Multiple studies, including several intervention trials, have demonstrated that rent subsidy programs are highly effective at reducing the risk of future homelessness and mitigating HIV risk behaviour among persons living with HIV and AIDS (Dasinger and Speiglman, 2007; Scott et al., 2007; Aidala et al., 2005; Elifson et al., 2007) and among low-income families (Shinn et al., 1998). Similar programs are likely to be equally effective for marginalized and at-risk youth. Given that rental prices in our setting for low-income and SRO housing increased by almost 8% from 2005 to 2007 (City of Vancouver, 2007), policies and structural-environmental interventions that prioritize the provision of safe and stable housing for homeless and street-involved youth are urgently required in our setting.

The present study has several limitations that should be noted. Although extensive snowball and outreach-based sampling methods were conducted in an attempt to derive a representative sample of street-involved youth, we are unable to generalize our results to the entire street youth population in Vancouver. With respect to this concern, it is noteworthy that the demographic profile of our sample is very similar to other studies of street-involved adolescents that have been conducted in our setting previously (Ochnio et al., 2001; Martin et al., 2006). However, it is important to note that particularly hard to reach subpopulations of street youth such as those under the age of 14 remain underrepresented in our and in other studies. Secondly, self-reported sexual behaviours are known to be highly susceptible to reporting and recall bias. Since the accuracy of such reports increases with shorter recall periods (Fenton et al., 2001), we attempted to maximize the accuracy of the data by restricting our analysis to recent (past six month) behaviours and outcomes. Thirdly, our analyses were restricted to sexual activity that did not occur in the context of sex in exchange for money, drugs, gifts, or shelter. Future research should be conducted to examine the specific environmental factors associated with sexual risk behaviour and HIV/STI transmission among young street-involved sex workers in Vancouver. Lastly, the data is cross-sectional, and therefore the relationships between explanatory variables and sexual risk behaviour outcomes do not imply causality. In particular, causal inferences with respect to housing conditions and street youth sexual behaviour must be tempered by the fact that only current place of residence was assessed and individuals may have lived in multiple locations over the six month period of interest. Future studies should examine longitudinally whether the frequency at which street-involved youth change housing conditions impacts the likelihood of engagement in sexual risk behaviours.

In summary, the results of our study suggest that housing status may influence sexual risk behaviour and therefore may play an important role in driving HIV and STI transmission among street-involved youth. Along with LGBTT orientation, housing status was independently associated with both greater numbers of sex partners and inconsistent condom use. These results support the adoption and evaluation of structural-environmental frameworks that explicitly include environmental determinants of HIV and STI transmission, and suggest that policies, law, and programs be restructured to prioritize housing conditions and other environmental factors as primary prevention strategies. Our results add to a growing literature that indicates HIV and STI prevention efforts must target the environmental-structural contexts in which disease is transmitted and risk is produced.


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