Health Sciences, Faculty of

Receive updates for this collection

Does Size Really Matter? A Sensitivity Analysis of Number of Seeds in a Respondent-Driven Sampling Study of Gay, Bisexual and Other Men Who Have Sex With Men in Vancouver, Canada

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2016-11-16
Abstract: 

Background Respondent-driven sampling (RDS) is an increasingly used peer chain-recruitment method to sample “hard-to-reach” populations for whom there are no reliable sampling frames. Implementation success of RDS varies; one potential negative factor being the number of seeds used. Methods We conducted a sensitivity analysis on estimates produced using data from an RDS study of gay, bisexual and other men who have sex with men (GBMSM) aged ≥16 years living in Vancouver, Canada. Participants completed a questionnaire on demographics, sexual behavior and substance use. For analysis, we used increasing seed exclusion criteria, starting with all participants and subsequently removing unproductive seeds, chains of ≤1 recruitment waves, and chains of ≤2 recruitment waves. We calculated estimates for three different outcomes (HIV serostatus, condomless anal intercourse with HIV discordant/unknown status partner, and injecting drugs) using three different RDS weighting procedures: RDS-I, RDS-II, and RDS-SS. We also assessed seed dependence with bottleneck analyses and convergence plots. Statistical differences between RDS estimators were assessed through simulation analysis. Results Overall, 719 participants were recruited, which included 119 seeds and a maximum of 16 recruitment waves (mean chain length = 1.7). The sample of   >0 recruitment waves removed unproductive seeds (n = 50/119, 42.0%), resulting in 69 chains (mean length = 3.0). The sample of >1 recruitment waves removed 125 seeds or recruits (17.4% of overall sample), resulting in 37 chains (mean length = 4.8). The final sample of >2 recruitment waves removed a further 182 seeds or recruits (25.3% of overall sample), resulting in 25 chains (mean length = 6.1). Convergence plots and bottleneck analyses of condomless anal intercourse with HIV discordant/unknown status partner and injecting drugs outcomes were satisfactory. For these two outcomes, regardless of seed exclusion criteria used, the crude proportions fell within 95% confidence intervals of all RDS-weighted estimates. Significant differences between the three RDS estimators were not observed. Conclusions Within a sample of GBMSM in Vancouver, Canada, this RDS study suggests that when equilibrium and homophily are met, although potentially costly and time consuming, analysis is not negatively affected by large numbers of unproductive or lowly productive seeds.

Document type: 
Article
File(s): 

An Integrated Approach to Care Attracts People Living with HIV who Use Illicit Drugs in an Urban Centre with a Concentrated HIV Epidemic

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2016-11-22
Abstract: 

Background People living with HIV (PLHIV) who are also marginalized by social and structural inequities often face barriers to accessing and adhering to HIV treatment and care. The Dr. Peter Centre (DPC) is a non-profit integrated care facility with a supervised injection room that serves PLHIV experiencing multiple barriers to social and health services in Vancouver, Canada. This study examines whether the DPC is successful in drawing in PLHIV with complex health issues, including addiction. Methods Using data collected by the Longitudinal Investigations into Supportive and Ancillary health services (LISA) study from July 2007 to January 2010, linked with clinical variables available through the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program, we identified DPC and non-DPC clients with a history of injection drug use. Bivariable and multivariable logistic regression analyses compared socio-demographic and clinical characteristics of DPC clients (n = 76) and non-DPC clients (n = 482) with a history of injection drug use. Results Of the 917 LISA participants included within this analysis, 100 (10.9%) reported being a DPC client, of which 76 reported a history of injection drug use. Adjusted results found that compared to non-DPC clients with a history of injection drug use, DPC-clients were more likely to be male (AOR: 4.18, 95% CI = 2.09–8.37); use supportive services daily vs. less than daily (AOR: 3.16, 95% CI = 1.79–5.61); to have been diagnosed with a mental health disorder (AOR: 2.11; 95% CI: 1.12–3.99); to have a history of interpersonal violence (AOR: 2.76; 95% CI: 1.23–6.19); and to have ever experienced ART interruption longer than 1 year (AOR: 2.39; 95% CI: 1.38–4.15). Conclusions Our analyses suggest that the DPC operating care model engages PLHIV with complex care needs, highlighting that integrated care facilities are needed to support the multiple intersecting vulnerabilities faced by PLHIV with a history of injection drug use living within urban centres in North America and beyond.

Document type: 
Article
File(s): 

Prevalence, Type, and Correlates of Trauma Exposure Among Adolescent Men and Women in Soweto, South Africa: Implications for HIV Prevention

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2016-11-25
Abstract: 

BACKGROUND: Youth trauma exposure is associated with syndemic HIV risk. We measured lifetime prevalence, type, and correlates of trauma experience by gender among adolescents living in the HIV hyper-endemic setting of Soweto, South Africa. METHODS: Using data from the Botsha Bophelo Adolescent Health Survey (BBAHS), prevalence of "ever" experiencing a traumatic event among adolescents (aged 14-19) was assessed using a modified Traumatic Event Screening Inventory-Child (TESI-C) scale (19 items, study alpha = 0.63). We assessed self-reported number of potentially traumatic events (PTEs) experienced overall and by gender. Gender-stratified multivariable logistic regression models assessed independent correlates of 'high PTE score' (≥7 PTEs). RESULTS: Overall, 767/830 (92%) participants were included (58% adolescent women). Nearly all (99.7%) reported experiencing at least one PTE. Median PTE was 7 [Q1,Q3: 5-9], with no gender differences (p = 0.19). Adolescent men reported more violent PTEs (e.g., "seen an act of violence in the community") whereas women reported more non-violent HIV/AIDS-related PTEs (e.g., "family member or someone close died of HIV/AIDS"). High PTE score was independently associated with high food insecurity among adolescent men and women (aOR = 2.63, 95%CI = 1.36-5.09; aOR = 2.57, 95%CI = 1.55-4.26, respectively). For men, high PTE score was also associated with older age (aOR = 1.40/year, 95%CI = 1.21-1.63); and recently moving to Soweto (aOR = 2.78, 95%CI = 1.14-6.76). Among women, high PTE score was associated with depression using the CES-D scale (aOR = 2.00, 95%CI = 1.31-3.03,) and inconsistent condom use vs. no sexual experience (aOR = 2.69, 95%CI = 1.66-4.37). CONCLUSION: Nearly all adolescents in this study experienced trauma, with gendered differences in PTE types and correlates, but not prevalence. Exposure to PTEs were distributed along social and gendered axes. Among adolescent women, associations with depression and inconsistent condom use suggest pathways for HIV risk. HIV prevention interventions targeting adolescents must address the syndemics of trauma and HIV through the scale-up of gender-transformative, youth-centred, trauma-informed integrated HIV and mental health services.

Document type: 
Article
File(s): 

Changes in Mortality Rates and Causes of Death in a Population-Based Cohort of Persons Living With and Without HIV from 1996 to 2012

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-02
Abstract: 

BACKGROUND: Non-HIV/AIDS-related diseases are gaining prominence as important causes of morbidity and mortality among people living with HIV. The purpose of this study was to characterize and compare changes over time in mortality rates and causes of death among a population-based cohort of persons living with and without HIV in British Columbia (BC), Canada. METHODS: We analysed data from the Comparative Outcomes And Service Utilization Trends (COAST) study; a retrospective population-based study created via linkage between the BC Centre for Excellence in HIV/AIDS and Population Data BC, and containing data for HIV-infected individuals and the general population of BC, respectively. Our analysis included all known HIV-infected adults (≥ 20 years) in BC and a random 10% sample of uninfected BC adults followed from 1996 to 2012. Deaths were identified through Population Data BC - which contains information on all registered deaths in BC (BC Vital Statistics Agency dataset) and classified into cause of death categories using International Classification of Diseases (ICD) 9/10 codes. Age-standardized mortality rates (ASMR) and mortality rate ratios were calculated. Trend test were performed. RESULTS: 3401 (25%), and 47,647 (9%) individuals died during the 5,620,150 person-years of follow-up among 13,729 HIV-infected and 510,313 uninfected individuals, respectively. All-cause and cause-specific mortality rates were consistently higher among HIV-infected compared to HIV-negative individuals, except for neurological disorders. All-cause ASMR decreased from 126.75 (95% CI: 84.92-168.57) per 1000 population in 1996 to 21.29 (95% CI: 17.79-24.79) in 2011-2012 (83% decline; p < 0.001 for trend), compared to a change from 7.97 (95% CI: 7.61-8.33) to 6.87 (95% CI: 6.70-7.04) among uninfected individuals (14% decline; p < 0.001). Mortality rates from HIV/AIDS-related causes decreased by 94% from 103.85 per 1000 population in 1996 to 6.72 by the 2011-2012 era (p < 0.001). Significant ASMR reductions were also observed for hepatic/liver disease and drug abuse/overdose deaths. ASMRs for neurological disorders increased significantly over time. Non-AIDS-defining cancers are currently the leading non-HIV/AIDS-related cause of death in both HIV-infected and uninfected individuals. CONCLUSIONS: Despite the significant mortality rate reductions observed among HIV-infected individuals from 1996 to 2012, they still have excess mortality risk compared to uninfected individuals. Additional efforts are needed to promote effective risk factor management and appropriate screening measures among people living with HIV.

Document type: 
Article
File(s): 

Validating a Self-Report Measure of HIV Viral Suppression: An Analysis of Linked Questionnaire and Clinical Data from the Canadian HIV Women's Sexual and Reproductive Health Cohort Study

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-03
Abstract: 

BACKGROUND: We assessed the validity of a self-report measure of undetectable viral load (VL) among women with HIV in British Columbia (BC), Canada. Questionnaire data from the Canadian HIV Women's Sexual and Reproductive Health Cohort Study was linked with population-based clinical data from the BC Centre for Excellence in HIV/AIDS. Self-reported undetectable VL was assessed by the question: "What was your most recent VL, undetectable (i.e. <50 copies/mL) or detectable (i.e. ≥50 copies/mL)?" Laboratory measurements of VL <50 copies/mL (closest to/before study visit) were the criterion for validity analyses. We measured positive and negative predictive values (PPV, NPV) and likelihood ratios (LR+, LR-). RESULTS: Of 356 participants, 99% were linked to clinical data. Those unlinked (n = 1), missing self-report VL (n = 18), or missing self-report and laboratory VL (n = 1) were excluded. Among the remaining 336: median age was 44 (IQR 37-51); 96% identified as cis-gender; 84% identified as heterosexual; and 45% identified as Indigenous, 40% White, 8% African, Caribbean, or Black, and 8% other/multiple ethnicities. Overall, 85% self-reported having an undetectable VL while 82% had clinical data indicating viral suppression. The PPV was 93.7 (95% CI 90.2-96.2) indicating that 94% of women who self-reported being undetectable truly were. The NPV was 80.4 (95% CI 66.9-90.2). LR+ was 3.2 (2.1-4.6) and LR- was 0.05 (0.03-0.10). CONCLUSIONS: Our self-report measure assessing undetectable VL strongly predicted true viral suppression among Canadian women with HIV. This measure can be used in research settings without laboratory data in regions with high rates of VL testing and suppression.

Document type: 
Article
File(s): 

Conspiracy Beliefs and Knowledge About HIV Origins Among Adolescents in Soweto, South Africa

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-02-02
Abstract: 

We examined adolescents' knowledge regarding the origin of HIV/AIDS and correlates of beliefs surrounding conspiracy theories in Soweto, South Africa. Now, a decade post-AIDS denialism, South Africa has the largest antiretroviral therapy roll-out worldwide. However, conspiracy theories stemming from past AIDS denialism may impact HIV prevention and treatment efforts.

Document type: 
Article
File(s): 

Global Health Governance: We Need Innovation not Renovation

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-03-09
Abstract: 

Although the global health community widely accepts that WHO, as currently configured, is no longer fit-for-purpose, commentators cling to renovation (‘reform’), rather than innovation, at the expense of a global health governance system that reflects the needs of a very changed world.Collective action in a globalised world requires institutions that look very different from what we currently have. Rather than the renovation of outdated institutional forms—which are closed, territorially fixed and hierarchical—we need to harness innovations such as social networks, open-source systems and the sharing economy.One of the biggest forms of institutional innovation more broadly is ‘network governance’, by which collective action is achieved through interconnected institutions spanning government, business and civil society.

Document type: 
Article
File(s): 

Controlling Corporate Influence in Health Policy Making: An Assessment of the Implementation of Article 5.3 of the World Health Organization Framework Convention on Tobacco Control

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-03-08
Abstract: 

The World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC) stands to significantly reduce tobacco-related mortality by accelerating the introduction of evidence-based tobacco control measures. However, the extent to which States Parties have implemented the Convention varies considerably. Article 5.3 of the FCTC, is intended to insulate policy-making from the tobacco industry's political influence, and aims to address barriers to strong implementation of the Convention associated with tobacco industry political activity. This paper quantitatively assesses implementation of Article 5.3's Guidelines for Implementation, evaluates the strength of Parties' efforts to implement specific recommendations, and explores how different approaches to implementation expose the policy process to continuing industry influence.

Highly selective and incomplete implementation of specific guideline recommendations facilitates extensive ongoing opportunities for industry policy influence. Stronger commitment to implementation is required to ensure consistently strong compliance with the FCTC internationally.

Document type: 
Article
File(s): 

The Globalisation Strategies of Five Asian Tobacco Companies: A Comparative Analysis and Implications for Global Health Governance

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-01-31
Abstract: 

The global tobacco industry, from the 1960s to mid 1990s, saw consolidation and eventual domination by a small number of transnational tobacco companies (TTC). This paper draws together comparative analysis of five case studies in the special issue on 'The Emergence of Asian Tobacco Companies: Implications for Global Health Governance.' The cases suggest that tobacco industry globalisation is undergoing a new phase, beginning in the late 1990s, with the adoption of global business strategies by five Asian companies. The strategies were prompted foremost by external factors, notably market liberalisation, competition from TTCs and declining domestic markets. State protection and promotion enabled the industries in Japan, South Korea and China to rationalise their operations ahead of foreign market expansion. The TTM and TTL will likely remain domestic or perhaps regional companies, JTI and KT&G have achieved TTC status, and the CNTC is poised to dwarf all existing companies. This global expansion of Asian tobacco companies will increase competition which, in turn, will intensify marketing, exert downward price pressures along the global value chain, and encourage product innovation. Global tobacco control requires fuller understanding of these emerging changes and the regulatory challenges posed by ongoing globalisation.

Document type: 
Article
File(s): 

‘Preparing Ourselves to Become an International Organization’: Thailand Tobacco Monopoly’s Regional and Global Strategies

Peer reviewed: 
Yes, item is peer reviewed.
Date created: 
2017-01-31
Abstract: 

The Thailand Tobacco Monopoly (TTM) controlled the country's tobacco industry from its formation in the 1940s, until the government dropped restrictions on imported cigarettes in the late 1980s in response to pressure from the United States. The TTM has since competed with transnational tobacco companies (TTCs) in a semi-monopoly market in which TTCs have steadily increased their market share. Coupled with a decline in national smoking prevalence, the result of Thailand's stringent tobacco control agenda, the TTM now accounts for a diminishing share of a contracting market. In response, the monopoly has looked to regional trade liberalisation, and proximity to markets with some of the world's highest smoking rates to expand its operations. Expansion strategies have gone largely unrealised however, and the TTM effectively remains a domestic operation. Using TTM publications, market and trade reports, industry publications, tobacco industry documents and other resources, this paper analyses TTM expansion strategies, and the limited extent to which they have been achieved. This inability to expand its operations has left the monopoly potentially vulnerable to global strategies of its transnational competitors. This article is part of the special issue 'The Emergence of Asian Tobacco Companies: Implications for Global Health Governance'.

Document type: 
Article
File(s):