Department of Public Health Sciences Graduate Theses
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Item A frailty index for predicting mortality, healthcare resources and costs of cardiac procedure patients(2024-12-23) Hore, Elizabeth; Public Health Sciences; Johnson, Ana; Lu, ZihangBackground: Canada’s aging population is growing steadily. Older age is associated with frailty, defined as the accumulation of age and illness-related deficits, which can be measured using a frailty index. Objectives: 1) To develop a non-weighted and weighted frailty index for cardiac procedure patients and to use these to predict mortality. 2) To develop a weighted frailty index for cardiac procedures to predict healthcare utilization and costs. For objectives 1 and 2, the created frailty indices were compared with an existing frailty index. 3) To explore healthcare provider and hospital administrator perspectives on the clinical usefulness and feasibility of implementing a frailty index for cardiac procedures. Methods: This was a retrospective cohort study involving cardiac procedure patients using healthcare administrative data followed by key informant interviews with providers and hospital administrators using reflexive thematic analysis. Results: 64,822 open-heart surgery patients and 2,024 transcatheter aortic valve implantation (TAVI) patients were included in the retrospective cohort studies. For predicting mortality, the multivariable regression model containing the weighted frailty index showed a small improvement in the open-heart surgery cohort versus the non-weighted index model (concordance-statistic=0.80 [95% Confidence Interval (CI): 0.78,0.81] versus 0.79 [95% CI: 0.77,0.80] respectively). In the TAVI cohort, the pre-existing frailty index model had the greatest prediction capability. For healthcare costs, the weighted frailty index model demonstrated the highest predictive abilities in both cohorts. For length of initial hospital stay, the weighted frailty index model had the highest prediction abilities in the open-heart surgery cohort and similar capabilities to the model containing the pre-existing frailty index in the TAVI cohort. Key informant interviews revealed four themes regarding a cardiac procedure-specific frailty index: (1) potential uses; (2) feasibility for prehabilitation; (3) logistics of implementation; (4) future implementation. Subthemes included surgical candidacy and electronic incorporation of the index into health information systems. Conclusion: Researchers may choose the pre-existing frailty index for predicting TAVI mortality or the weighted frailty index when predicting healthcare costs and resources. A cardiac procedure-specific frailty index could be useful to healthcare providers when determining surgical candidacy and optimizing preoperative care, especially if electronically integrated into health information systems.Item Quarantine and Mental Health During COVID-19: Exploring the Impact on Depressive Symptoms and Suicidal Ideation Among Adults in Canada(2024-10-09) Towheed, Shahnawaz; Public Health Sciences; Heather, StuartBackground: The COVID-19 pandemic led to significant public health measures, including mandatory quarantine, which had potential mental health implications. This thesis investigated the association between mandatory quarantine and mental health outcomes, specifically depressive symptoms and suicidal ideation, among adults in Canada. Objectives: The primary objective was to assess whether mandatory quarantine due to close contact with a COVID-19 case was associated with increased odds of depressive symptoms and suicidal ideation. Secondary objectives included identifying key demographic, socioeconomic, and psychosocial factors that may act as effect modifiers or confounders to these associations. Methods: A cross-sectional analysis was conducted using data from a national survey by Mental Health Research Canada. The study sample included 3012 Canadian adults who participated in the sixth poll conducted in April 2021. Logistic regression models were used to examine the associations between quarantine and the mental health outcomes, adjusting for potential confounders such as age, prior mood disorders, and resilience. Results: Quarantine was not significantly associated with depressive symptoms after adjusting for confounders (AOR = 1.25, 95% CI: 0.90 to 1.73). Similarly, no significant association was found between quarantine and suicidal ideation (AOR = 1.07, 95% CI: 0.69 to 1.65). However, strong associations were observed for other factors. Having a history of a prior mood disorder was significantly associated with both depressive symptoms (AOR = 5.02, 95% CI: 4.07 to 6.20) and suicidal ideation (AOR = 5.97, 95% CI: 4.05 to 7.92). Older age was consistently protective against both outcomes, with the 65+ age group showing the lowest odds of depressive symptoms (AOR = 0.27, 95% CI: 0.19 to 0.39) and suicidal ideation (AOR = 0.25, 95% CI: 0.14 to 0.42). Conclusions: While quarantine itself was not a significant predictor of depressive symptoms or suicidal ideation after adjusting for confounders, the findings underscored the importance of considering pre-existing mood disorders and demographic factors in understanding mental health risks during public health crises. Targeted interventions for high-risk populations, particularly those with a history of mood disorders, remain crucial in mitigating the mental health impacts of such crises in the future.Item The Association Between Perceived Psychosocial Supports and Resilience Among Female Venezuelan Refugees and Migrants(2024-10-04) Josic, Maxwell Filip; Public Health Sciences; Bartels, Susan; Stoner, BradleyBackground: Migrants experience profound threats to their mental health, with women and girls facing additional vulnerabilities, like sexual exploitation and trafficking. Resilience acts in opposition to these threats, protecting against mental health decline through mental, emotional, and behavioural adaptations. A central component of resilience is perceived psychosocial support (PPS), which describes the provision of practical, material, and emotional assistance by others in order to mitigate the impacts of stressors on individuals. This study examines the association between PPS and resilience among displaced Venezuelan women and girls and hypothesizes they are positively correlated. Methods: This is a secondary analysis of a larger, qualitative/quantitative, cross-sectional study (2022) involving 9116 female Venezuelan migrants in Brazil, Ecuador, and Peru. Following the ‘sensemaking’ methodology, each participant shared a brief experience and completed a questionnaire that contextualized their shared experience and collected demographic data. Data from 5990 micro-narratives shared by women aged 14 or older were included in the analysis. Using SAS statistical software (SAS® 9.4 TS1M3), three quantitative analyses were performed: 1) descriptive statistical analysis, 2) bivariate analysis, and 3) multivariate logistic regression modelling (using backward elimination with a generous inclusion threshold of p<0.20). Results: Overall, 65% of participants were fully resilient. The final regression model included five of eight potential confounders: age, ethnicity, miscellaneous health issues, length of displacement, and relative wealth. Participants in the top tertile of PPS had 2.13 times the odds of resilience compared to the bottom tertile (95% CI: [1.84, 2.47], p<0.0001), while no significant difference was found between the bottom and middle tertiles (95% CI: [0.87, 1.14], p=0.91). Health issues, low relative wealth, and a longer time since displacement were associated with lower resilience, while age correlated with higher resilience. Finally, the relationship between ethnicity and resilience varied depending on the self-identified ethnic background. Conclusions: This study confirmed that PPS plays an important role in the resilience of forcibly displaced Venezuelan women and girls, and elucidated several unexpected results deserving of further investigation, such as the null association between resilience and self-identifying as LGBTQ+. Future studies should administer validated resilience questionnaires to better understand the contributions of the constituent components of resilience in this population. The results of this investigation can be used to more efficiently direct humanitarian mental health resources and develop tailored resilience-fostering interventions for this large, at-risk population.Item Reconsidering Teen Pregnancy as a Public Health “Problem”: A Phenomenological Study of Intentional Teen Pregnancy Through the Experiences and Perspectives of Teen Mothers in Canada(2024-10-04) Dutton, Sherri; Public Health Sciences; Davison, ColleenThe main objective of this thesis was to explore intentional teen pregnancy in Canada in relation to the field of public health through young mothers’ perspectives and experiences. This thesis consists of four manuscripts, three of which are empirical studies and one that is a conceptual manuscript, as well as an overarching methodology chapter. The first manuscript is a critical scoping review exploring public health research orientations to intentional teen pregnancy in Canada. Results argue that much of public health research in Canada is focused on biomedical and individualistic discourses related to pregnancy and is limited in terms of methodological diversity and public health action. The second manuscript assesses public health communications related to perinatal risk for teen and older age pregnancies in Ontario using comparative framing and qualitative content analysis. Results of this study present two differential frames of perinatal risk: risk as part of societal benefit for older age pregnancies and risk as part of societal disadvantage for teenage pregnancies. Analysis highlights how societal values shape public health communications, adding to the growing scholarship within critical health communication research. The third manuscript uses Bourdieusian analysis to explore the experiences, perceptions, and motivations of young mothers in Ontario. This manuscript shows young mothers to be motivated by the potential transformative and positive impacts of motherhood, while simultaneously facing oppression through racist, classist, gendered, and ageist valuations of capital. Results of this study argues that public health efforts have the potential to uphold or work against the oppression related to teen pregnancy in Canada. The fourth and final manuscript is a conceptual piece reflecting on my use of a resistance epistemology in public health research. This manuscript argues a resistance epistemology helps to overcome epistemological barriers such as epistemic violence and oppression within teen pregnancy research and adds to the growing scholarship around epistemologies in public health research. Following these manuscripts is a general discussion where I (re)consider the field of public health related to teen pregnancy within an anti-oppressive lens through pivoting the center of public health practice and reaffirming a social justice approach.Item Patient-level factors associated with delays to adjuvant chemotherapy in female patients with breast cancer(2024-09-30) Stevens, Taylor; Public Health Sciences; Wijeratne, Don Thiwanka; King, WillBackground: Longer time to initiation of adjuvant chemotherapy following surgery (TTC) is associated with worse patient outcomes in breast cancer treatment. This thesis examined patient sociodemographic and clinical factors for their relationships with TTC through a scoping review and analysis of data from patients who received treatment at the National Cancer Institute Sri Lanka (NCISL). Methods: A scoping review was conducted by searching MEDLINE, EMBASE, CINHAL, Web of Science, and grey literature repository databases for papers that evaluated patient sociodemographic and clinical factors for association with TTC in breast cancer treatment. A single-institution retrospective cohort study was performed with data from female patients with stage II-III breast cancer treated at the NCISL. Delay in TTC was defined as initiation >12 weeks following surgery. A Poisson regression with robust variance estimation was used to estimate the independent relationships of patient sociodemographic and clinical factors with delayed TTC. Results: In the scoping review, 49 papers met the inclusion criteria and 41 patient sociodemographic and clinical factors were identified. The most commonly evaluated factors were age, stage, and surgical complications. Retrospective cohort designs and administrative or clinical data were most often used. A paucity of studies from lower middle income (LMIC) and low-income country (LIC) contexts was identified. The cohort study included 2,907 female patients who had undergone surgery for stage II-III breast cancer and received adjuvant chemotherapy within 6 months of surgery. The median TTC was 6.1 weeks and 11.9% of participants experienced delay. An age ≥70 years compared to <40 years, having less than three children compared to three or more, having no education compared to secondary level or higher, having a primary hospital outside the Western Province of Sri Lanka, and wide local excision compared to mastectomy with or without reconstruction were found to be associated with delayed TTC. Conclusion: More research in the area of TTC is necessary in the context of LMIC and LICs. The findings of this study contribute to by identifying factors in the context of a LMIC that can be used to identify patients at risk for delayed TTC and inform targeted intervention.