The Associations Between Shift Work Exposure and Selected Health Outcomes Among Middle-Aged and Older Adults, Results from the Canadian Longitudinal Study on Aging

We live in a globalized 24-hour society, consuming services, products and entertainment around the clock. As a result, more and more people are working in shifts. Currently, one in every four Canadians is working in shifts other than regular daytime hours. At the same time, the working population is aging and are becoming more common in most developed nations, including Canada. Together with physiological and epidemiological data on the alarming relationships between shift work and various physical, social and mental health outcomes, there is reason to believe that shift work may become a major occupational health problem in the near future. This dissertation analyzed data from the Canadian Longitudinal Study on Aging (CLSA) and investigated the associations between shift work and three specific outcomes related to health of middle-aged and older adults, specifically variations in age at natural menopause, frailty and cognitive impairment. The primary exposure, shift work, was measured using three derived variables: ever exposed to shift work, shift work exposure in current job, and shift work exposure in longest job. Multivariable analysis revealed that exposure to shift work is significantly related to adverse health outcomes among middle-aged and older adults. These findings highlight how shift work affects the health of the aging labor force. It also serves as a reminder of the importance of taking modifiable risk factors like shift work into account when developing and implementing health interventions in old age. It is believed that shift work, through circadian misalignment and melatonin suppression, interfere with human homeostasis and wellbeing, however, further research is needed to confirm this.