Shiftwork, sleep disturbance and the metabolic syndrome among female hospital workers

Background: Shiftwork is associated with increased sleep disturbance and cardiovascular and metabolic disease risk. This thesis will focus on shiftwork-related sleep disturbance and the potential mediating role of reduced sleep duration in the relationship between a current rotational shiftwork schedule and the metabolic syndrome among female hospital employees. Objectives: 1) To describe sleep patterns in relation to different shiftwork exposure metrics (current status, cumulative exposure, number of consecutive night shifts); 2) To assess the association between shiftwork metrics and sleep duration; 3) To determine whether sleep duration on work shifts mediates the relationship between a current rotational shiftwork pattern and the metabolic syndrome; and 4) To assess whether cumulative shiftwork exposure and the number of consecutive night shifts are associated with the metabolic syndrome. Methods: 294 female hospital employees (142 rotating shiftworkers, 152 dayworkers) participated in a cross-sectional study. Shiftwork parameters were determined through self-report. Sleep was measured for one week with the ActiGraph GT3X+, a tri-axial accelerometer. The metabolic syndrome was defined according to the Joint Interim Studies Consensus Statement. Sleep was described by shiftwork exposure parameters, and multivariable linear regression was used to determine associations between shiftwork variables and sleep duration. Regression path analysis was used to assess whether sleep duration was a mediator between a current shiftwork schedule and the metabolic syndrome, and the significance of the indirect (mediating) effect was tested with bootstrap confidence intervals. Logistic regression was used to determine associations between cumulative shiftwork exposure, number of consecutive night shifts, and the metabolic syndrome. Results: Current shiftworkers slept less on work shifts, more on free days, and were more likely to nap compared to dayworkers. Sleep duration on work shifts was a strong intermediate in the relationship between a current shiftwork pattern and the metabolic syndrome. Cumulative shiftwork exposure and the number of consecutive night shifts did not affect sleep or the metabolic syndrome. Conclusions: A current shiftwork pattern disrupts sleep, and reduced sleep duration is an important intermediate between shiftwork and the metabolic syndrome among female hospital employees.

(MIS)PERCEIVED DRINKING NORMS AND HAZARDOUS DRINKING BEHAVIOURS IN UNIVERSITY FIRST-YEAR UNDERGRADUATE STUDENTS AND THE EFFECTS OF GENDER

Purpose: Across Canada, undergraduate university students are one of the highest alcohol-consuming populations. Many students engage in hazardous drinking and are at risk for negative health and social consequences. Social Norms Theory suggests that students’ overestimation of drinking norms can result in an increase in their drinking behaviour. As of yet, none of the literature addresses the possible link between drinking norm (mis)perception and hazardous drinking in a Canadian undergraduate context. This is the first Canadian study to examine this potential association in first-year undergraduate students across multiple universities using gender as an effect modifier. Methods: Using data collected by the Caring Campus Project, for 2347 first-year students from three Canadian universities, I evaluated the prevalence of drinking norm misperceptions by site and gender. Using multiple-logistic regression models, I analyzed the relationship between misperceived drinking norms and hazardous drinking behaviours (assessed via AUDIT-C). Results: The proportion of students who overestimated drinking and binge drinking frequency norms varied by site and gender. There was a positive relationship between overestimated drinking/ binge drinking frequency norms and hazardous drinking, modified by gender. Controlling for living arrangement and site, the odds of female students being hazardous drinkers increased by a factor of 2.27 (CI: 1.73-2.99) when the drinking frequency norm was overestimated. A non-significant association was found for male students. Among female students, when living arrangement and site were controlled, the odds of being a hazardous drinker were 1.83 (0.84-3.95) and 2.69 (1.24-5.83) times greater when the drinking frequency norm was perceived at “2-4 times per month” and “2 or more times per week”, respectively. Among male students, when living arrangement, previous residence and site were controlled, the odds of being a hazardous drinker were 4.03 (2.62-6.19) and 8.54 (5.41-13.49) times greater when the binge drinking frequency norm was perceived at “2-4 times per month” and “2 or more times per week”, respectively. Conclusion: This novel study enhances the understanding of the association between (mis)perceived drinking norms and drinking behaviours in Canadian undergraduate students. The demonstrated importance of gender and site provides a strong impetus for Canadian universities to develop targeted alcohol reduction interventions.

Randomized Trial for a Mobile Health Approach to Increase Uptake of Cervical Cancer Screening in Tanzania

Background: Largely due to low availability and uptake of screening in low- and middle-income countries, cervical cancer is the second ranked cancer among women in these countries. This is a tragedy because cervical cancer is one of the most preventable carcinomas. This thesis will investigate behaviour change methods, which capitalize on the recent exponential increase in ownership of mobile phones in Tanzania, to increase uptake of cervical cancer screening (CCS) in the Kilimanjaro region of Tanzania. Objectives: 1) To evaluate the effectiveness of behaviour change messages delivered via short message service (SMS) on the uptake of CCS in the Kilimanjaro region; 2) to evaluate the effectiveness of a transportation eVoucher on the uptake of CCS in the Kilimanjaro region; 3) to explore characteristics associated with CCS uptake in the Kilimanjaro region; and 4) to determine the attitudes towards and perceived benefit of behaviour change SMS messages and eVouchers intended to increase uptake of CCS. Methods: In the Kilimanjaro Region, 853 women participated in a randomized controlled trial. Baseline data was collected through self-report through systematic stratified random sampling. Participants were randomized to one of three groups: a control group, a group receiving behaviour change messages delivered via SMS, or a group receiving a travel eVoucher and identical SMS as the SMS group. A fieldworker recorded participants attending screening at the CCS clinics and administered a post-screening survey. The follow-up period was two months from the time of the participant’s enrolment. Logistic regression (both for the combined and stratified data sets) was used to determine associations between the behaviour change interventions, baseline characteristics and cervical cancer screening uptake. Results: All participants receiving SMS messages (SMS or eVoucher group) were more likely to attend cervical cancer screening in comparison with the control group. 83% of participants who attended screening shared the information contained in the messages with others. Conclusions: Behaviour change messages delivered via SMS and transportation eVouchers have the potential to increase uptake of cervical cancer screening in the Kilimanjaro region of Tanzania. Harnessing this potential will require implementing these interventions alongside other methods to achieve maximum impact.