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

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A Behavioral Ecology Approach to Trade-offs in Reproduction: Modelling Women’s Reproductive Strategies and Empirical Studies of Post-partum Amenorrhea

Author: 
Date created: 
2016-07-26
Abstract: 

Reproductive behaviors are shaped by a plethora of selective pressures, past and present. On an ecological time scale, reproductive “decisions” are made by balancing life-history trade-offs that are dependent on intrinsic and extrinsic factors, such as resource availability and age. Mathematical models are powerful tools that allow for the systematic investigation of such factors, and to test whether selective forces thought to be responsible for particular traits had been correctly identified. In this thesis, I present a dynamic state variable model for the optimization of reproductive scheduling under a range of family and environmental contexts. Next, I test one of the model’s simplifying assumptions, that sons and daughters cost the same to produce and to raise, via secondary data analysis of two existing data sets. These results are discussed in parallel to the benefits of applying principles of evolutionary ecology to public health problems.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Pablo Nepomnaschy
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Caregivers’ Treatment-Seeking Behaviors for Malaria in Children Five and Under: A Field Study in Uganda’s Butaleja District

Author: 
Date created: 
2015-05-21
Abstract: 

Background: Reducing malaria mortality is a global priority. Uganda has focused its national strategic plan to have by 2010: 85% of children under five receive first-line antimalarials within 24 hours of fever onset and following diagnostic confirmation. In 2004, artemisinin-combination therapies (ACTs) were adopted as first-line treatment for uncomplicated malaria in children older than 4-months. Method: A three-study series investigated caregivers’ malaria related treatment-seeking behaviors for young children to inform future public health initiatives in Uganda’s Butaleja District: a literature review, a household survey, and a multiple case study. In this document, these appear as three manuscripts in Chapters 2-4. Results: While drug delivery improvements have increased ACT usage, these studies concur that initiatives still failed to meet the 2010 national target. Only 21% of children received blood tests, 31.6% received no antimalarials, 31.6% received “appropriate” (only first-line) antimalarials, and 36.8% received subordinate antimalarials. Among subordinates, 5.8% of children were mis-prescribed ACTs and 22.4% received ACTs and subordinate antimalarials. Home management was an important initial treatment source since visits to public facilities were commonly associated with hardships. Caregivers’ knowledge and preference about antimalarials varied with prior experiences and beliefs. The survey evaluated 160 behavioral questions in determining four independent predictors of likelihood that a child would receive an “appropriate” antimalarial: obtaining antimalarials from regulated outlets (OR=14.99); keeping ACT in the home for future use (OR=6.36); reporting they would select ACT given the choice (OR=2.31); and child’s age older than 4 months (OR=5.67). The study further employed the Health Belief Model to identify 10 scales of “Assets” and “Challenges” to guide more precise insights into caregivers’ behaviors. Four “Asset” scales predicted significantly whether a child received an “appropriate” antimalarial: Precursors to Receiving an Appropriate Antimalarial (R2=21%); Episode Management (R2=39%); Caregiver Knowledge (R2=6%); and Professional Assistance with Critical Decision (R2=9%). Similarly, two “Challenge” scales were significant predictors: Lack of Assistance with Critical Decision (R2=9%), and Problems Obtaining a Best Antimalarial (R2=4%).Conclusions: To conform practice to policy, this research sequence highlighted the importance of engaging the full spectrum of stakeholders in public health initiatives to manage malaria, including licensed and unlicensed providers, caregivers and family members.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Robert Hogg
Department: 
Health Sciences:
Thesis type: 
(Thesis) Ph.D.

A systematic review on the incidence of injuries to young children and implications for prevention and surveillance

Date created: 
2016-04-04
Abstract: 

Introduction: Childhood injuries represent a significant public health problem, with young children being injured in often predictable ways. Injury surveillance – not currently done in Canada – could track the population burden and help identify factors amenable to prevention. Methods: A systematic review of the childhood injury incidence literature was conducted using methods adapted from the Cochrane Collaboration. Particular attention was paid to identifying injuries according to developmentally sensitive age groupings to avoid masking the incidence of specific injury types in younger children. Results: Eight incidence studies met appraisal criteria. The highest injury rate was 375 per 1,000 one-year-old boys in Alberta. Despite variability in data sources and reporting methods, it was possible to use these findings to suggest new approaches to child injury surveillance that are developmentally sensitive and grounded in ecological approaches to understanding injury etiology. Discussion: The implications for child injury research, prevention, and surveillance in Canada are reviewed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Charlotte Waddell
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Exploring intersectionality as a framework for advancing research on gay men’s health inequities

Author: 
Date created: 
2015-12-14
Abstract: 

While the rights of gay men have improved significantly over the past 40 years, the health inequities of this diverse population remain considerable and efforts to reverse the trend have yielded few results. This suggests that a radical shift is warranted into how we theorize, investigate and intervene in this area. Public health researchers have primarily focused on gay men’s behaviours to explain negative health outcomes while social factors have been largely neglected. To change this trend, intersectionality has been proposed as a framework to study gay men’s health inequities. Intersectionality promotes an understanding of humans as being shaped by the interaction of different social locations and structures of power. It is now recognized as an important framework to study health inequities. However, marginalized and multiply oppressed women are still the primary focus of much intersectional scholarship and the literature exploring the relationship between intersectionality and gay men’s health is still underdeveloped. Therefore, more work is needed theoretically, methodologically and empirically to grasp the potential contributions of intersectionality to the understanding of how health inequities of gay men are produced and sustained. In this dissertation I explore how intersectionality can help transform the field of gay men’s health research, and help attend to issues of gay men’s health inequities more effectively. This was accomplished by uniting in one collection three case studies, each looking at how intersectionality can transform a different aspect of research: theorizing, methodology, and data analysis. Together, the three case studies demonstrate that intersectionality can 1) disrupt essentialist assumptions and the false homogenization of gay men in public health research and therefore bring forward issues of diversity more effectively; 2) illuminate interactive power dynamics affecting gay men’s health such as systemic heterosexism, sexism, and racism as well as power differences operating within gay communities such as racism, classism and misogyny; 3) produce new and more accurate knowledge about health inequities due to its attention to multiple and intersecting factors. In light of these results, I conclude that intersectionality is more than a useful framework for gay men’s health research; it is critical to reversing gay men’s health inequities.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Marina Morrow
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

Mentoring and the Public Health Workforce: A Scoping Review

Date created: 
2015-07-02
Abstract: 

This study sought to better understand mentoring in the training of the public health workforce, and to identify key issues in the conceptualization and application of mentoring and its potential relevance to public health. Methods entailed a scoping review of literature in Medline, CINAHL, and Web of Science databases following guidelines in the PRISMA standards. A total of 1809 references between 2000 and June 2014 were identified, of which 27 met inclusion criteria. Very little research on the topic has been published. The main thematic areas were the models used in mentoring, the value of mentoring, mentors' and mentees' perceptions and needs, attributes of successful mentoring relationships, elements for the design and evaluation of mentoring programs, and authors’ recommendations. The main conclusion is that mentoring is a growing interest in relation to developing the public health workforce. To improve mentoring models and practices, further research should be conducted.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Kitty Corbett
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Engagement in care among adolescents and young adults living with HIV in Canada

Date created: 
2015-09-22
Abstract: 

Background: More than thirty years after the beginning of the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic, HIV continues to be a problem among adolescents and young adults (AYA).. The benefits of combination antiretroviral therapy (cART), including lower morbidity and improved survival, are realized through timely uptake of treatment, virological suppression, and retention in care; however, compared with their adult counterparts, AYA living with HIV tend to have poorer treatment and clinical outcomes. In the current context of UNAIDS’ ambitious 90-90-90 campaign, there is a push to expand cART to all those in need in order to reduce morbidity/mortality and to curb transmission of HIV. We will not achieve the 90-90-90 goals without addressing HIV treatment and outcomes among AYA; however this population remains under-researched; to date there is very little research describing AYA living with HIV in Canada. The overall aim of this dissertation is to examine key cART treatment outcomes among Canadian AYA (ages 18-29 years) living with HIV and compare outcomes with those of older adults (30 years and older). Methods: The quantitative studies in this dissertation utilize clinical and laboratory data from the Canadian Observational Cohort Collaboration (CANOC), Canada’s largest HIV cohort study, which includes data from the year 2000 onward on a total of 10,044 people living in three of Canada’s largest provinces—British Columbia, Ontario, and Quebec. All participants in CANOC are HIV-positive and were cART-naive prior to initiating antiretroviral treatment on or after January 1, 2000. Findings: There are 1168 (13.7%) AYA (ages 18-29 years) in CANOC. Significant differences in treatment outcomes were found between AYA and older adults. AYA were more likely than older adults to initiate cART before their CD4 counts were <200 cells/mm3 and/or they had an AIDS-defining illness (ADI) (51.7% vs 40.2% p<0.001). When looking at virological suppression, fewer AYA experienced virological suppression than older adults (86% vs. 91%, p<0.001) and of these, only 73% (compared with 80% of older adults) suppressed within the first year of cART inititation (p<0.001). Additionally, a greater proportion of AYA who achieved virological suppression experienced viral rebound than older adults (26% vs. 22%, p=0.009). Discussion: When comparing AYA with older adults, AYA are more likely to initiate treatment when recommended but once on treatment, they are less likely to virologically suppress and remain suppressed. The importance of supporting AYA to achieve optimal health is a long-term investment with benefits over the life course. In order to meet ambitious public health goals such as those that the UNIADS 90-90-90 campaign has set, AYA will require tailored health care services and programming to assist them to access and remain in care.

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

Global-Fundization: HIV/AIDS funding mechanisms and programming in Sierra Leone

Date created: 
2015-05-08
Abstract: 

This thesis explores how the Global Fund’s standardized funding stipulations and expectations impact HIV/AIDS programs in Sierra Leone. Situating funding mechanisms within the current trajectory of international healthcare delivery and financing, I argue that the Global Fund’s business-oriented financing approach has shaped Sierra Leonean program targets towards data production and digitization, allowing the Global Fund to make decisions ‘from a distance.’ Drawing on three months of ethnographic fieldwork in Freetown, Sierra Leone, I demonstrate how: 1) contradictions between weak infrastructure and Global Fund expectations impact HIV program practices; 2) the Global Fund’s data requirements and timeframes create asymmetries and disconnects in-country; and 3) audit and accountability technologies in HIV programs can become practices unrelated to health outcomes.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Susan L. Erikson
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Elucidating the consequences of HIV-1 immune escape from host CTL selection pressure

Author: 
Date created: 
2015-08-05
Abstract: 

This thesis focuses on HIV-1 adaptation to CTL immune response and presents original data on the consequences of 10 published HLA-B*13-associated CTL escape mutations in Gag, Pol and Nef on HIV-1 replication capacity (RC) and Nef-mediated CD4 and HLA class I downregulation. B*13-driven immune escape at Gag-I147L and -I437L incurred replicative costs of 5% and 17% on in vitro viral RC, which was rescued to wild-type (HIV-1NL4.3) levels by Gag-A146S/K436R and Gag-K436R, respectively. One major observation was that B*13-driven double mutation, NefE24Q/Q107R impaired this protein’s HLA class I downregulation ability by 40%, with no evidence of replicative or expression defects. Moreover, cells infected with double mutant virus were “visible” to HIV-specific T cells. Our results thus suggest that B*13-mediated protective effects on HIV-1 disease progression may be attributable, in part to a novel mechanism – namely, the selection of escape mutations in Nef that dampen one of HIV-1’s key immune evasion strategies.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Zabrina Brumme
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.Sc.

Associations between biogeoclimatic zones, aquifer type, agricultural land and five gastrointestinal illnesses in British Columbia from 2000-2013 and potential implications under projected climate change

Author: 
Date created: 
2015-05-14
Abstract: 

Rates of five acute gastrointestinal illnesses (AGIs) were calculated across three environmental variables in British Columbia: biogeoclimatic zone, aquifer type and agricultural land. The three bacterial pathogens (campylobacteriosis, Verotoxin-producing Escherichia coli and salmonellosis) were strongly correlated with many temperature-related variables calculated at the biogeoclimatic zone level. Combined relative risk for the three bacterial AGIs was 1.11189 (p=0.006) for every degree Celsius increase in mean annual temperature. When amalgamated into two groups (bacteria and parasites) both groups had significantly higher proportions associated with unconsolidated aquifers than with bedrock aquifers. Verotoxin-producing Escherichia coli rates were significantly higher in watersheds with agricultural land than those with none. Conversely, rates of campylobacteriosis, salmonellosis and giardiasis were significantly lower in agricultural watersheds.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Tim Takaro
Diana Allen, Margot Parkes, Stephen Dery
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.Sc.

Cervical Screening in Swaziland: an Ethnographic Case Study

Date created: 
2015-07-31
Abstract: 

This thesis examines and contextualizes women’s fears about cervical screening in Swaziland. I begin with a critique of the historical and epidemiological trend to blame screening avoidance among African women on cultural fears. Then, drawing on data from semi-structured interviews and participant observation, I find that fear of cervical screening is a product of the clinical, social and political contexts of screening, thus challenging assumptions about culture-based fear. The clinical encounter between women and nurses is laborious; complicated by fears of gossip, the pejorative judgment of women’s bodies and hospital politics. The complexities of this encounter collide with politically produced realities of cancer treatment scarcity, therapeutic failure and HIV’s dominance of local clinical space to further create and sustain fear. Ultimately, women’s fears of cervical screening are logical, and must be understood relative to the complex backdrop of clinical sociality, politics and scarcity that situates cervical cancer in Swaziland.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Susan Erikson
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.Sc.