A comparison of drug use and risk behavior profiles among younger and older street youth

Among 559 street youth recruited between 2005 and 2007 in Vancouver, Canada, young drug users (<21 years of age) were compared with older drug users (≥21 years) with regard to recent drug use and sexual practices using multiple logistic regression. Older youth were more likely to be male and of Aboriginal ancestry, to have more significant depressive symptoms, to have recently engaged in crack smoking, and to have had a recent history of injection drug use. Young drug users, by contrast, were more likely to have engaged in recent binge alcohol use. Efforts to reduce drug use-related harm among street youth may be improved by considering the highly prevalent use of "harder" drugs and risk for depression among older youth.

Pathways to HIV risk and vulnerability among lesbian, gay, bisexual, and transgendered methamphetamine users: a multi-cohort gender-based analysis

Background

Methamphetamine (MA) use continues to be a major public health concern in many urban settings. We sought to assess potential relationships between MA use and individual, social, and structural HIV vulnerabilities among sexual minority (lesbian, gay, bisexual or transgendered) drug users.

Methods

Beginning in 2005 and ending in 2008, 2109 drug users were enroled into one of three cohort studies in Vancouver, Canada. We analysed longitudinal data from all self-identified sexual minority participants (n = 248). Logistic regression using generalized estimating equations (GEE) was used to examine the independent correlates of MA use over time. All analyses were stratified by biological sex at birth.

Results

At baseline, 104 (7.5%) males and 144 (20.4%) females reported sexual minority status, among whom 64 (62.1%) and 58 (40.3%) reported MA use in the past six months, respectively. Compared to heterosexual participants, sexual minority males (odds ratio [OR] = 3.74, p < 0.001) and females (OR = 1.80, p = 0.003) were more likely to report recent MA use. In multivariate analysis, MA use among sexual minority males was associated with younger age (adjusted odds ratio [AOR] = 0.93 per year older, p = 0.011), Aboriginal ancestry (AOR = 2.59, p = 0.019), injection drug use (AOR = 3.98, p < 0.001), having a legal order or area restriction (i.e., "no-go zone") impact access to services or influence where drugs are used or purchased (AOR = 4.18, p = 0.008), unprotected intercourse (AOR = 1.62, p = 0.048), and increased depressive symptoms (AOR = 1.67, p = 0.044). Among females, MA use was associated with injection drug use (AOR = 2.49, p = 0.002), Downtown South residency (i.e., an area known for drug use) (AOR = 1.60, p = 0.047), and unprotected intercourse with sex trade clients (AOR = 2.62, p = 0.027).

Conclusions

Methamphetamine use was more prevalent among sexual minority males and females and was associated with different sets of HIV risks and vulnerabilities. Our findings suggest that interventions addressing MA-related harms may need to be informed by more nuanced understandings of the intersection between drug use patterns, social and structural HIV vulnerabilities, and gender/sexual identities. In particular, MA-focused prevention and treatment programs tailored to disenfranchised male and female sexual minority youth are recommended.

Household-level correlates of condom use among a representative sample of Canadian adolescents

BACKGROUND

The relationship between an adolescent's micro-environment (e.g. the home) and the likelihood of engagement in sexual risk behaviour is poorly understood. Therefore, we sought to examine the household-level correlates of condom use at last intercourse among a nationally representative sample of Canadian adolescents aged 15 to 19.

METHODS

Using data from the 2005 Canadian Community Health Survey, we conducted logistic regression analyses to determine whether factors related to characteristics of the household environment were associated with self-reported condom use at last intercourse.

RESULTS

Among 3974 sexually active adolescents, condom use at last intercourse was reported by 74.8%. After adjusting for household education and income, participants who reported living in larger dwellings were less likely to report condom non-use, while those reporting greater numbers of persons in the household were more likely to report condom non-use. Other significant correlates of condom non-use included older age, female sex, alternative birth control methods and having a weak sense of community belonging.

CONCLUSION

Our results demonstrate that factors related to the household environment are independently associated with condom use among adolescents. Policies and programs that aim to promote condom use should seek to address issues such as privacy, which may limit adolescents' ability to engage in safer sexual practices.

Health outcomes associated with methamphetamine use among young people: a systematic review

OBJECTIVES

Methamphetamine (MA) use among young people is of significant social, economic and public health concern to affected communities and policy makers. While responses have focused upon various perceived severe harms of MA use, effective public health interventions require a strong scientific evidence base.

METHODS

We conducted a systematic review to identify scientific studies investigating health outcomes associated with MA use among young people aged 10-24 years. The International Classification of Diseases (ICD-10) was used to categorize outcomes and determine the level of evidence for each series of harms.

RESULTS

We identified 47 eligible studies for review. Consistent associations were observed between MA use and several mental health outcomes, including depression, suicidal ideation and psychosis. Suicide and overdose appear to be significant sources of morbidity and mortality among young MA users. Evidence for a strong association between MA use and increased risk of human immunodeficiency virus (HIV) and other sexually transmitted infections is equivocal. Finally, we identified only weak evidence of an association between MA use and dental diseases among young people.

CONCLUSIONS

Available evidence indicates a consistent relationship between MA use and mental health outcomes (e.g. depression, psychosis) and an increased risk of mortality due to suicide and overdose. We found insufficient evidence of an association between MA use and other previously cited harms, including infectious diseases and dental outcomes. As such, future research of higher methodological quality is required to further investigate possible associations. Current interventions should focus attention upon MA-related health outcomes for which sound scientific evidence is available.

Childhood trauma and injection drug use among high-risk youth

We examined the association between five types of childhood maltreatment and initiation of injection drug use among a cohort of high-risk youth in Vancouver, Canada. Among 560 participants, 230 (41.1%) had injected drugs previously. In multivariate logistic analyses, only physical abuse (adjusted odds ratio = 1.91, 95% confidence interval: 1.29-2.83) was associated with injection drug use. These findings highlight the impact of childhood physical abuse on subsequent initiation into injection drug use among high-risk youth.

Injection drug use among street-involved youth in a Canadian setting

Background

Street-involved youth contend with an array of health and social challenges, including elevated rates of blood-borne infections and mortality. In addition, there has been growing concern regarding high-risk drug use among street-involved youth, in particular injection drug use. We undertook this study to examine the prevalence of injection drug use and associated risks among street-involved youth in Vancouver, Canada.

Methods

From September 2005 to November 2007, baseline data were collected for the At-Risk Youth Study (ARYS), a prospective cohort of street-recruited youth aged 14 to 26 in Vancouver, Canada. Using multiple logistic regression, we compared youth with and without a history of injection.

Results

The sample included 560 youth among whom the median age was 21.9 years, 179 (32%) were female, and 230 (41.1%) reported prior injection drug use. Factors associated with injection drug use in multivariate analyses included age ≥ 22 years (adjusted odds ratio [AOR] = 1.18, 95% CI: 1.10–1.28); sex work involvement (AOR = 2.17, 95% CI: 1.35–3.50); non-fatal overdose (AOR = 2.10, 95% CI: 1.38–3.20); and hepatitis C (HCV) infection (AOR = 22.61, 95% CI: 7.78–65.70).

Conclusion

These findings highlight an alarmingly high prevalence of injection drug use among street-involved youth and demonstrate its association with an array of risks and harms, including sex work involvement, overdose, and HCV infection. These findings point to the need for a broad set of policies and interventions to prevent the initiation of injection drug use and address the risks faced by street-involved youth who are actively injecting.

Longitudinal community plasma HIV-1 RNA concentrations and incidence of HIV-1 among injecting drug users: prospective cohort study

OBJECTIVE

To examine the relation between plasma HIV-1 RNA concentrations in the community and HIV incidence among injecting drug users.

DESIGN

Prospective cohort study.

SETTING

Inner city community in Vancouver, Canada.

PARTICIPANTS

Injecting drug users, with and without HIV, followed up every six months between 1 May 1996 and 30 June 2007.

MAIN OUTCOME MEASURES

Estimated community plasma HIV-1 RNA in the six months before each HIV negative participant's follow-up visit. Associated HIV incidence.

RESULTS

Among 622 injecting drug users with HIV, 12 435 measurements of plasma HIV-1 RNA were obtained. Among 1429 injecting drug users without HIV, there were 155 HIV seroconversions, resulting in an incidence density of 2.49 (95% confidence interval 2.09 to 2.88) per 100 person years. In a Cox model that adjusted for unsafe sexual behaviours and sharing used syringes, the estimated community plasma HIV-1 RNA concentration remained independently associated with the time to HIV seroconversion (hazard ratio 3.32 (1.82 to 6.08, P<0.001), per log(10) increase). When the follow-up period was limited to observations after 1 January 1988 (when the median plasma HIV RNA concentration was <20 000 copies/ml), the median viral load was no longer statistically associated with HIV incidence (1.70 (0.79 to 3.67, P=0.175), per log(10) increase).

CONCLUSIONS

A longitudinal measure of community plasma HIV-1 RNA concentration was correlated with the community HIV incidence rate and predicted HIV incidence independent of unsafe sexual behaviours and sharing used syringes. If these findings are confirmed, they could help to inform both HIV prevention and treatment interventions.

Structural factors associated with an increased risk of HIV and sexually transmitted infection transmission among street-involved youth

Background

The prevalence of HIV and sexually transmitted infections (STIs) among street-involved youth greatly exceed that of the general adolescent population; however, little is known regarding the structural factors that influence disease transmission risk among this population.

Methods

Between September 2005 and October 2006, 529 street-involved youth were enroled in a prospective cohort known as the At Risk Youth Study (ARYS). We examined structural factors associated with number of sex partners using quasi-Poisson regression and consistent condom use using logistic regression.

Results

At baseline, 415 (78.4%) were sexually active, of whom 253 (61.0%) reported multiple sex partners and 288 (69.4%) reported inconsistent condom use in the past six months. In multivariate analysis, self-reported barriers to health services were inversely associated with consistent condom use (adjusted odds ratio [aOR] = 0.52, 95%CI: 0.25 – 1.07). Structural factors that were associated with greater numbers of sex partners included homelessness (adjusted incidence rate ratio [aIRR] = 1.54, 95%CI: 1.11 – 2.14) and having an area restriction that affects access to services (aIRR = 2.32, 95%CI: 1.28 – 4.18). Being searched or detained by the police was significant for males (aIRR = 1.36, 95%CI: 1.02 – 1.81).

Conclusion

Although limited by its cross-sectional design, our study found several structural factors amenable to policy-level interventions independently associated with sexual risk behaviours. These findings imply that the criminalization and displacement of street-involved youth may increase the likelihood that youth will engage in sexual risk behaviours and exacerbate the negative impact of resultant health outcomes. Moreover, our findings indicate that environmental-structural interventions may help to reduce the burden of these diseases among street youth in urban settings.

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 (ARYS). Among 529 participants, 253 (47.8%) reported multiple partners while only 127 (24.0%) reported consistent condom use in the past 6 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.

High prevalence of HIV infection among homeless and street-involved Aboriginal youth in a Canadian setting

Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth. We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline, 15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection (odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants (p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention among Aboriginal young people are urgently required.

The contextual determinants of sexually transmissible infections among street-involved youth in North America

Young people living on the urban street are at a significantly increased risk of HIV and other sexually transmitted infections (STIs). Much research examining the epidemiological basis for their heightened susceptibility has concentrated on the individual behaviours and characteristics associated with acquiring these infections. However, contextual factors, including the social, structural and environmental forces that influence sexual risk behaviour, are increasingly found to play an important role in shaping the transmission dynamics of HIV and STIs within these marginalised populations. This paper reviews research describing the individual and contextual factors that have been shown to influence street youth sexual behaviour and provides an analysis of the potential impact of such factors on HIV and STI transmission. In order to implement effective sexual health programmes for street-involved young people, innovative programmes are required that take into account the unique social and structural context of youth homelessness. Interventions to reduce the elevated prevalence and incidence of HIV and STIs among this population must explicitly target multi-level factors influencing the transmission dynamics of these diseases.

Condom use among injection drug users accessing a supervised injecting facility

OBJECTIVES

Although supervised injecting facility (SIF) use has been associated with reductions in injection-related risk behaviours, the impact of SIFs on the sexual behaviour of injection drug users (IDUs) has not been thoroughly investigated. Therefore, we examined the patterns and predictors of condom use among SIF users in Vancouver, Canada.

METHODS

We performed a longitudinal analysis of the factors associated with consistent condom use among IDUs recruited from within a SIF.

RESULTS

Among 1090 individuals, 650 (59.6%) reported a sexual partner in the past 6 months at baseline. Consistent condom use was reported by 108 (25.3%) and 205 (61.6%) individuals reporting regular or casual partners, respectively. After 2 years of observation, these proportions increased to 32.9% and 69.8%, respectively. In multivariate analysis, predictors of consistent condom use with regular partners included HIV positivity (adjusted odds ratio (AOR) 2.23; 95% CI 1.51 to 3.31), injecting with a sex partner (AOR 0.50; 95% CI 0.37 to 0.68), enrollment in addiction treatment (AOR 0.68, 95% CI 0.52 to 0.89) and time since recruitment (AOR 1.29; 95% CI 1.06 to 1.55 per year). Predictors of consistent condom use with casual partners included HIV positivity (AOR 1.70; 95% CI 1.03 to 2.81), syringe borrowing (AOR 0.54; 95% CI 0.32 to 0.91) and syringe lending (AOR 0.52; 95% CI 0.32 to 0.84).

CONCLUSIONS

Our results demonstrate that among SIF users, consistent condom use was more frequent among casual sex partners and among HIV positive individuals. Importantly, while the prevalence of consistent condom use was low at baseline, it increased over time. Our findings suggest a possible beneficial effect of the SIF on safer sexual practices.

Highly active antiretroviral therapy and survival in HIV-infected injection drug users

CONTEXT

Highly active antiretroviral therapy (HAART) is often withheld from injection drug users (IDUs) infected with the human immunodeficiency virus (HIV) based on the belief that their unstable lifestyles may predetermine a markedly inferior outcome with HAART. However, long-term evaluations of HIV treatment outcomes among IDUs in comparison with other risk groups are not available.

OBJECTIVE

To compare survival rates among HIV-infected patients initiating HAART with and without a history of injection drug use.

DESIGN, SETTING, AND PATIENTS

Population-based, prospective cohort study (HAART Observational Medical Evaluation and Research [HOMER]) of 3116 antiretroviral-naive HIV-infected patients in a province-wide HIV/AIDS treatment program in British Columbia, Canada. Of the 3116 patients, 915 were IDUs (29.4%), 579 were female (18.6%), and the median age was 39.4 years (interquartile range, 33.3-46.4 years). Treatment with HAART was initiated between August 1, 1996, and June 30, 2006. The median duration of follow-up was 5.3 years (interquartile range, 2.8-8.3 years) for IDUs and 4.3 years (interquartile range, 2.0-7.6 years) for non-IDUs. Patients were followed up until June 30, 2007. Data were analyzed between November 1, 2007, and May 26, 2008.

MAIN OUTCOME MEASURE

All-cause mortality.

RESULTS

Overall, 622 individuals died (20.0%) during the study period (232 IDUs and 390 non-IDUs), for a crude mortality rate of 20.0% (95% confidence interval [CI], 18.4%-21.5%). At 84 months after the initiation of HAART, the product limit estimate of the cumulative all-cause mortality rate was similar between the 915 IDUs (26.5%; 95% CI, 23.2%-29.8%) and 2201 non-IDUs (21.6%; 95% CI, 16.9%-26.2%) (Wilcoxon P = .47). In multivariate time-updated Cox regression, the hazard ratio of mortality was similar between IDUs and non-IDUs (1.09; 95% CI, 0.92-1.29).

CONCLUSION

In this study population, injection drug use was not associated with decreased survival among HIV-infected patients initiating HAART.

Elevated syringe borrowing among men who have sex with men: a prospective study

OBJECTIVE

Despite efforts to scale up HIV prevention services for drug users, high rates of HIV risk behavior persist among some subpopulations. Given that few prospective studies have considered the relationship between sexual activity and syringe sharing, we sought to evaluate syringe sharing among male injection drug users (IDUs) who have sex with men (MSM) in Vancouver.

METHODS

We performed a longitudinal analysis of factors associated with syringe borrowing among male participants enrolled in the Vancouver Injection Drug Users Study during the years 1996 to 2005 using generalized estimating equations (GEE).

RESULTS

Among the 1019 male participants included in this analysis, 553 (54.3%) reported borrowing syringes during the study period. In multivariate GEE analysis, MSM were at an elevated risk for syringe borrowing (adjusted odds ratio [AOR] = 1.50, 95% confidence interval [CI]: 1.10 to 2.04) after extensive adjustment for other known risk factors.

CONCLUSIONS

Among male participants, having sex with men was found to be strongly and independently associated with syringe borrowing. Our findings may aid policy makers in their efforts to identify IDUs who should be targeted with education and prevention efforts, and indicate the need for ongoing development of prevention interventions that address sexual orientation.

A multistranded polymer model explains MinDE dynamics in E. coli cell division

In Escherichia coli, the location of the site for cell division is regulated by the action of the Min proteins. These proteins undergo a periodic pole-to-pole oscillation that involves polymerization and ATPase activity of MinD under the controlling influence of MinE. This oscillation suppresses division near the poles while permitting division at midcell. Here, we propose a multistranded polymer model for MinD and MinE dynamics that quantitatively agrees with the experimentally observed dynamics in wild-type cells and in several well-studied mutant phenotypes. The model also provides new explanations for several phenotypes that have never been addressed by previous modeling attempts. In doing so, the model bridges a theoretical gap between protein structure, biochemistry, and mutant phenotypes. Finally, the model emphasizes the importance of nonequilibrium polymer dynamics in cell function by demonstrating how behavior analogous to the dynamic instability of microtubules is used by E. coli to achieve a sufficiently rapid timescale in controlling division site selection.