An investigation of sugar-sweetened beverage consumption among Canadian youth

Background: Consumption of sugar-sweetened beverages (SSBs) is an important public health problem in Canada, especially among adolescents. Estimates show that rates of SSB consumption are particularly high in the northern territories, especially in Nunavut. This is concerning given that regular SSB consumption is associated with obesity, diabetes and tooth decay, among other health concerns. Objectives: This thesis has two objectives. The first is to describe SSB consumption patterns among adolescents from Nunavut specifically, all three territories combined and the provinces.The second is to determine the association between individual and cumulative school food programs and SSB consumption. Methods: Data were obtained from the Health Behaviour in School-aged Children study (HBSC); a cross-sectional survey of Canadian youth in grades 6-10. All frequencies for food and beverage consumption were obtained from a 7-day food frequency questionnaire. SSB consumption consisted of a composite measure including soft drinks, sports drinks and energy drinks. The types of school food programs were obtained from an administrative questionnaire filled out by each school’s Principal or delegate. Multilevel multivariate Poisson regression models were used to examine the associations between school food programs and SSB consumption. Results: Youth from Nunavut consumed the most SSBs (53.1% in 2010 and 55.0% in 2014 were daily consumers), followed by youth from the territories (31.1% in 2010 and 27.0% in 2014), then youth from the provinces (24.3% in 2010 and 19.1% in 2014). No significant relationships were found between school food programs and daily SSB consumption. Two school food programs were weakly associated with weekly SSB consumption: nutrition month activities (RR=0.93,CI=0.89, 0.98) and healthy options in the snack bar (RR=1.07, CI=1.01, 1.14). Conclusions:Rates of SSB consumption were highest among Nunavummiut youth followed by youth from all three territories combined and then the provinces. Little association was found between school food programs and SSB consumption among Canadian youth in grades 6-10. These findings point to the need for examining other determinants and potential areas for intervention, for reducing SSB consumption among Canadian youth, particularly in high consumer sub-populations.

Adiposity, Sex Hormones, and Repetitive Element DNA Methylation in Healthy Postmenopausal Women

INTRODUCTION: Low levels of methylation within repetitive DNA elements, such as long interspersed nuclear element-1 (LINE-1) and Alu repeats, are believed to epigenetically predispose an individual to cancer and other diseases. The extent to which lifestyle factors affect the degree of DNA methylation within these genomic regions has yet to be fully understood. Adiposity and sex hormones are established risk factors for certain types of cancer and other illnesses, particularly amongst postmenopausal women. The aim of the current investigation is to assess the impact of adiposity and sex hormones on LINE-1 and Alu methylation in healthy postmenopausal women. METHODS: A cross-sectional study was conducted using baseline data from an ancillary study of the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial. Current adiposity was measured using a dual-energy x-ray absorptiometry (DXA) scan, computed tomography (CT) scan, and balance beam scale. Historical weights were self-reported in a questionnaire. Current endogenous sex hormone concentrations were measured in fasting blood serum. Estimated lifetime number of menstrual cycles was used as a proxy for cumulative exposure to ovarian sex hormones. Repetitive element methylation was quantified in white blood cells using a pyrosequencing assay. Linear regression was used to model the relations of interest while adjusting for important confounders. RESULTS: Adiposity and serum estrogen concentrations were positively related to LINE-1 methylation but were not associated with Alu methylation. Cumulative ovarian sex hormone exposure had a “U-shaped” relation with LINE-1 regardless of folate intake and a negative relation with Alu methylation amongst low folate consumers. Androgens were not associated with repetitive element DNA methylation in this population. CONCLUSION: Adiposity and estrogens appear to play a role in maintaining high levels of repetitive element DNA methylation in healthy postmenopausal women. LINE-1 methylation may be a mechanism whereby estrogen exposure protects against cardiovascular and neurodegenerative illnesses. These results add to the growing body of literature showing how the epigenome is shaped by our lifestyle choices. Future prospective studies assessing the relation between levels of repetitive element DNA methylation in healthy individuals and subsequent disease risk are needed to better understand the clinical significance of these results.

Unsettling Histories: Representation and Indigenous Creative Art Praxis in Official Indian Residential School Redress

This dissertation offers an investigation of the role of visual strategies, art, and representation in reconciling Indian Residential School history in Canada. This research builds upon theories of biopolitics, settler colonialism, and race to examine the project of redress and reconciliation as nation and identity building strategies engaged in the ongoing structural invasion of settler colonialism. It considers the key policy moments and expressions of the federal government—from RCAP to the IRSSA and subsequent apology—as well as the visual discourse of reconciliation as it works through archival photography, institutional branding, and commissioned works. These articulations are read alongside the creative and critical work of Indigenous artists and knowledge producers working within and outside of hegemonic structures on the topics of Indian Residential School history and redress. In particular the works of Jeff Thomas, Adrian Stimson, Krista Belle Stewart, Christi Belcourt, Luke Marston, Peter Morin, and Carey Newman are discussed in this dissertation. These works must be understood in relationship to the normative discourse of reconciliation as a legitimizing mechanism of settler colonial hegemony. Beyond the binary of cooptation and autonomous resistance, these works demonstrate the complexity of representing Indigeneity: as an ongoing site of settler colonial encounter and simultaneously the forum for the willful refusal of contingency or containment.