Health Sciences - Theses, Dissertations, and other Required Graduate Degree Essays

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Kidney Transplant Outcomes for Prolonged Cold Ischemic Times in the Context of Kidney Paired Donation

Date created: 
2017-07-21
Abstract: 

The need for kidneys outweighs the current organ supply. This study examines the impact of longer cold ischemic time (CIT) on graft outcomes to help expand living donor transplantation in kidney paired donation (KPD). In a retrospective cohort study of 48,498 living donor (LD) recipients in the United States between 2005-15, multivariate survival analyses reveal no association between CIT <16 hours for all-cause graft loss, or death-censored graft loss (hazard ratios for CIT 8.0-16.0 hours (0.97; 95% CI 0.74-1.26) and (1.09; 95% CI 0.81-1.48) respectively, compared to CIT 0.1-2.0 hours). These results were robust in LD >50 years and in KPD and non-KPD transplants. While there was a higher incidence of delayed graft function (DGF) in groups with longer CIT, the overall incidence of DGF was low. Multivariate regression analyses show increased odds of DGF only in CIT 8.1-16 hours compared to 0.1-2.0 hours (odds ratio: 1.47; 95% CI 1.05-2.05).

Document type: 
Thesis
File(s): 
Senior supervisor: 
Malcolm Steinberg
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.P.H.

Modelling Fine Particulate Matter Concentrations inside the Homes of Pregnant Women in Ulaanbaatar, Mongolia

Author: 
Date created: 
2017-06-30
Abstract: 

Fine particulate matter (PM2.5) is a leading public health risk factor globally. Indoor concentrations are an important determinant of exposure because people spend the majority of time indoors. I developed models for predicting PM2.5 concentrations inside the homes of pregnant women in Ulaanbaatar, Mongolia. The work was part of a randomized controlled trial of portable air cleaner use during pregnancy, fetal growth, and early childhood development. Multiple linear regression (MLR) and random forest regression (RFR) were used to model indoor PM2.5 concentrations using 7-day indoor PM2.5 measurements and potential predictors obtained from outdoor monitoring data, questionnaires, home assessments, and geographic data sets. The MLR (R2 = 50.5%) and RFR (R2 = 47.8%) models explained a moderate amount of variation in log-transformed indoor PM2.5. Model predictions can be used to evaluate associations between indoor PM2.5 concentrations during pregnancy and development in early life.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Ryan Allen
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Tobacco industry targeting of youth in Nigeria since the 1990s: An analysis of tobacco industry documents

Author: 
Date created: 
2017-10-19
Abstract: 

This study analyses the tactics and strategies used by transnational tobacco companies (TTCs) to target youth in Nigeria since the 1990s. Nigeria is considered by the tobacco industry to be a major emerging market given its population, demographic profile, and growing wealth. The study systematically searched the Truth Tobacco Industry Documents Library, available primary and secondary sources on industry activities in Nigeria, and conducted key informant interviews. It applied the theory of triadic influence as a heuristic framework to analyse the collected data. The findings suggest that TTCs have actively targeted youth in Nigeria, seeking to change behaviour through the biological/personality, and environmental/cultural and social streams. This has taken place against a backdrop of weak tobacco control policy despite Nigeria’s adoption of the Framework Convention on Tobacco Control. The study makes recommendations to strengthening youth protections under the National Tobacco Control Bill adopted into law in 2015.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Kelley Lee
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Cancer risk among women living with HIV: Implications for care in the modern cART era

Author: 
Date created: 
2017-06-28
Abstract: 

Following the advent of modern combination antiretroviral therapy (cART) in 1996, a temporal decline was widely observed in AIDS-related morbidity and mortality. In the province of British Columbia (BC), universal provision of cART free-of-charge for people living with HIV (PLHW) has contributed in part to a significant demographic shift, with individuals over 50 years of age comprising over half of all PLHW. In this context there is a need to understand how comorbidities, such as cancer, impact this aging cohort. Within this line of inquiry, it is imperative to look at cancer risk specifically amongst women living with HIV (WLWH). The majority of studies looking at cancer as a co-morbid condition among PLWH fail to conduct sex-stratified analyses, which may obscure the burden of cancer risk specific to WLWH. Using a Life Course Epidemiology framework, the objectives of this PhD dissertation were to: 1) measure cancer incidence among WLWH in BC compared to a general population sample of women; 2) identify the role of early cART initiation in mitigating excess risk of cancer observed among WLWH; and 3) estimate the burden of cancer-related mortality among PLWH. This research utilized administrative health data from Population Data BC (which included data from the BC Cancer Agency and Vital Statistics) and clinical HIV data from the BC Centre for Excellence in HIV/AIDS. Findings suggest WLWH experience an increased risk of certain cancers, notably for certain viral-related malignancies, in comparison to HIV-negative women in the modern cART era. A protective effect of early initiation of cART therapy was found for some types of cancer, suggesting oncological health benefits might be associated with timely initiation of cART after HIV diagnosis for WLWH. Finally, sex stratified age-adjusted cancer-related mortality rates promisingly suggest there may not be significantly different cancer-related mortality outcomes between PLWH and the general population. This dissertation demonstrates that cancer-related morbidity is a healthcare priority for the growing aging demographic of WLWH and subsequently highlights the importance of appropriate and effective routine cancer screening measures as well as comprehensive HIV care inclusive of timely diagnosis and cART initiation.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Robert Hogg
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

Going beyond health-related quality of life for outcome measurement in economic evaluation

Author: 
Date created: 
2017-07-04
Abstract: 

Background: The quality-adjusted life year (QALY) framework has been challenged for use in economic evaluation because of its narrow focus on health-related aspects of quality of life, thus ignoring potential ‘non-health’ benefits associated with treatments and interventions. With the development of new preference-based measures, such as the ICEpop CAPability (ICECAP) instruments that adopt a broader evaluative space, the aim of this thesis was to examine methodological considerations and applied implications for outcome measurement in health economics when applying measures that extend beyond health. Methods: A narrative review provides an overview of challenges involved for broadening the evaluative space of the QALY and the progress that has been made in this area. A critical interpretive synthesis (CIS) is then presented that conceptualized benefits beyond the health-related QALY, followed by three empirical analyses, each using a different dataset: (i) regression analyses testing the complementarity of a preference-based health-related quality of life (HRQoL) measure, the EQ-5D-5L, and a measure of capability wellbeing for older adults, the ICECAP-O, within the context of public health; (ii) exploratory factor analyses investigating the overlap between the ICECAP-A and five preference-based HRQoL measures; and (iii) path analyses to further explore the relationship between two HRQoL measures (EQ-5D-5L and AQoL-8D) and two wellbeing measures (ICECAP-A and subjective wellbeing). Results: The CIS conceptualized non-health benefits into four themes: (i) benefits affecting a person’s wellbeing (psychological wellbeing, subjective wellbeing, empowerment, and capability wellbeing); (ii) benefits derived from the process of health care delivery; (iii) benefits beyond the affected individual; and (iv) benefits beyond the health care sector. Three key findings were made from the empirical analyses that further explored wellbeing measures. Firstly, the ICECAP-O is more sensitive to environmental features (i.e., social cohesion and street connectivity) when compared with the EQ-5D-5L; secondly, the ICECAP-A contains domains in its descriptive system that are not measured by most HRQoL measures, except for the AQoL-8D; and thirdly, HRQoL and wellbeing measures are affected in a different way by different secondary health conditions but a similar relationship was found between the ICECAP-A and AQoL-8D. Conclusion: The thesis concludes that the application of wellbeing measures in economic evaluations requires careful consideration due to the risk of double counting. The capability approach has the potential to extend the QALY but the operationalization of this approach – and other non-health benefits within or outside the QALY framework – requires further research.

Document type: 
Thesis
File(s): 
Senior supervisor: 
David Whitehurst
Scott Lear
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

Canadians leaving the Canadian health care system to seek bariatric surgery abroad: Examining patient experience with international bariatric tourism

Date created: 
2017-06-09
Abstract: 

Globally, bariatric surgery, commonly known as weight loss surgery, has grown in popularity among obese individuals as a means to addressing their weight-related negative health when more traditional weight loss programs, such as diet and exercise, fail to elicit long term sustained weight loss. In Canada, however, complex barriers related to social, administrative, and other structural factors restrict access to care domestically, leaving some patients turning to surgical options abroad through the practice of medical tourism. In light of this, it is important that we understand the implications the practice of ‘bariatric tourism’ may hold for Canadians. Using an interview-based approach with former Canadian bariatric tourists, this study examines the patient experience of bariatric tourism. The analyses highlight specific barriers that are motivating patients to seek care internationally and challenges experienced in care obtainment both internationally and domestically that appear to heighten the health and safety risks these patients undertake.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Jeremy Snyder
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

The aryl hydrocarbon receptor nuclear translocator (ARNT) transcriptional co-regulator complex: Effects on estrogen and hypoxia signaling

Date created: 
2016-08-11
Abstract: 

The basic Helix-Loop-Helix/PER-ARNT-SIM (bHLH-PAS) domain family of proteins mediates cellular responses to a variety of stimuli. The bHLH-PAS proteins are heterodimeric transcription factors that are further sub-classified into sensory and aryl hydrocarbon receptor nuclear translocator (ARNT) proteins. The ARNT protein is constitutively expressed and heterodimerizes with hypoxia-inducible factors (HIFs) to mediate oxygen-sensing mechanisms and heterodimerizes with the aryl hydrocarbon receptor (AHR) to combat environmental contaminant exposure. Firstly, a reciprocal disruption relationship exists between AHR ligands, like 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and estrogen receptor (ER) ligands, like 17β-estradiol (E2). Ligand-bound ER tethers to the AHR/ARNT transcription factor complex and represses TCDD-inducible gene transcription. However, the tethering paradigm and molecular mechanisms employed by AHR and ARNT at ER-regulated genes remains to be determined. Secondly, thyroid hormone receptor/retinoblastoma-interacting protein 230 (TRIP230) interacts with ARNT and is a coactivator required for hypoxia-regulated transcription. The retinoblastoma protein (Rb) is a negative regulator of the cell cycle and also negatively regulates TRIP230 coactivator potential. Thus, Rb may influence ARNT transcription factor functions via TRIP230. Rb-loss in many solid tumours directly precedes the activation of HIF-regulated genes and correlates with increased angiogenesis and metastasis. As most solid tumours contain regions of hypoxia and only correlative data between HIF/ARNT activity and Rb-loss has been gathered, we have identified a need to rigorously examine the role of Rb-loss in concert with hypoxia in breast and prostate cancer models. In this thesis, I used siRNA technology to knockdown ARNT and AHR expression and found that TCDD-mediated disruption of ER-signalling is AHR-dependent and that ARNT is a coactivator in MCF7 cells and a corepressor in ECC1 cells. Additionally, I used siRNAs and shRNA technology in concert with microarray analysis in LNCaP prostate cancer cells and MCF7 breast cancer cells to delineate the role of the ARNT-TRIP230-Rb transcriptional complex in hypoxia-regulated transcription. I found that Rb-depletion in conjunction with hypoxia exacerbates HIF1-mediated transcription and promotes a more invasive and late stage phenotype in both breast and prostate cancer models. The molecular mechanisms and gene pathways described herein should prove useful for developing chemotherapies for late stage breast and prostate cancers.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Timothy Beischlag
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

Sexual self-efficacy among adolescent men and women living in an HIV-hyper-endemic setting of South Africa

Date created: 
2017-04-12
Abstract: 

Adolescent women in South Africa face disproportionate HIV acquisition. In this context, evidence remains mixed on whether sexual self-efficacy (SSE)- one’s perceived control in decision-making regarding safe sex, predicts consistent condom use (CCU). Using cross-sectional survey data from 830 adolescent men and women aged 14-19 living in Soweto, South Africa, this thesis conducted gender-based analyses to examine determinants of high-SSE (study-alpha=0.75) and the association between high-SSE and CCU. Results revealed women have higher SSE than men. High-SSE was associated with CCU use for men, but not women. For women, high-SSE was associated with having an adult in the home, and no history of physical violence. Moreover, lower depressive symptomology among women was more predictive of CCU than SSE, indicating that gender-targeted HIV prevention interventions must move beyond individual-level determinants of behaviour to address socio-structural and relational factors influencing syndemic HIV risk among adolescent women in South Africa.

Document type: 
Thesis
Senior supervisor: 
Dr. Robert Hogg
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

How Much Help? How Much Harm? Working class women’s experiences of prenatal care in East Vancouver

Author: 
Date created: 
2017-03-06
Abstract: 

This project sought to interrogate the institution of prenatal care in East Vancouver through the lived experiences of working class and historically marginalized women. Prenatal care in British Columbia is a complex of institutional policies and practices. This project focused on prenatal visits between pregnant women and their chosen maternity care provider. Through the stories and experiences of nine research participants, this project affords insight into how the work of prenatal care might be improved to better the experiences and health outcomes for working class and historically marginalized women and their newborns. This could include integrating more substantive ways of centering women in the institution of prenatal care and recruiting women as active participants, such as the use of group care and lay health care workers. Pregnancy is a time of great change for working class and historically marginalized women, attempts to reduce social inequity can start with the institutions that provide women care throughout pregnancy.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Nicole Berry
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Impacts of a new Greenway on older adult mobility: A mixed-methods analysis in Vancouver, BC

Author: 
Date created: 
2017-04-19
Abstract: 

Our population is aging, and life expectancies are increasing globally. One strategy to promote healthy aging is by creating environments that support physical activity. Using a natural experiment study design, this dissertation takes a mixed-methods approach to capture the impacts of a built environment intervention aimed to increase active transportation among community-dwelling older adults. We captured location-specific travel and physical activity using accelerometers and GPS monitors one year before and after the Comox-Helmcken Greenway was developed, and measured change in weekly transportation-related activity, specific activity along the Greenway, and activity along a comparison corridor. Secondly, we interviewed a subset of these older adults to capture their perceptions of the Greenway. We found no change in weekly physical activity levels, but a decrease in the number of trips along the Greenway. Our interview data suggests this may result from confusion of messaging, the steep slope, and a lack of destinations.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Meghan Winters
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.