Aperçu

Résumé (français)

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Résumé (anglais)

There is growing evidence that shift workers are at increased risk of cancer and a number of chronic diseases. As the prevalence of shift work is unlikely to decrease, an understanding of the factors that contribute to, and strategies that can be used to mitigate this risk are needed. Physical activity is known to improve health, and reduce chronic disease risk. However, evidence suggests that women shift workers may be less likely than other women to be sufficiently physically active. This dissertation aims to examine the effect that physical activity may have on improving health and reducing breast cancer risk in shift workers, by employing a variety of research methodologies. The first study is a systematic review of the literature on interventions aimed at improving the health of shift workers. This was conducted to understand what strategies have been most effective, as well as to identify gaps in the literature. The second study used crosssectional data from the Canadian Health Measures Survey to understand patterns of physical activity and sedentary time in shift workers compared to day workers, as well as objective measures of physical fitness and obesity. The third and fourth studies aimed to understand women shift workers’ perspectives on physical activity, particularly barriers to and preferences for physical activity programming, using quantitative and qualitative research methods respectively. Findings from these four studies led to the development of a distance-based physical activity intervention, consisting of behavioural counselling sessions, and use of an activity tracker to encourage participants to meet Canada’s physical activity guidelines of 150 minutes per week of moderate-vigorous physical activity. This intervention was found to be feasible to implement in women shift workers, with preliminary evidence of efficacy. In summary, these studies highlight the important role that physical activity may play in improving health and reducing breast cancer risk in women shift workers. The intervention developed lays the groundwork for future randomized-controlled trials to determine the magnitude of the effect that regular physical activity may have on shift workers’ risk of breast cancer and other chronic diseases.