Scientific Symposium - The Health Effects of Shift Work - Toronto, April 12, 2010

The prevalence of shift work in Canada

Paul A. Demers (presenter), Imelda Wong and Chris McLeod


One third of the Canadian labour force does not work a regular daytime shift. Work during night, evening, and rotating shifts has the greatest potential for disturbing sleep patterns and the disruption of circadian rhythms. Shift work involving night and evenings has been associated with a wide variety of health effects, including an increased risk of workplace injury, heart disease, and cancer. These health effects may be expected to vary by both industry and sex. For example, the underlying risk of workplace injury may vary significantly by industry and the strongest evidence for cancer is for breast cancer among women. In this paper we will describe the patterns of shift work in Canada.

Based on the 2005 Survey of Labour and Income Dynamics conducted by Statistics Canada, approximately 12% of employed Canadians worked rotating shifts while 6% worked regular evenings and 2.3% worked regular night shifts. "Accommodation and food services" is the sector with the largest proportion of the labour force working these shifts (40%), but other large sectors such as "Manufacturing" and "Health care and social assistance" also have large proportions (27% and 26% respectively). In terms of absolute numbers, "Health care and social assistance" is the sector with the largest number of women (n=334,000) working rotating, evening or night shifts, closely followed by "Trade" (n=309,000) and "Accommodation and food services" (n=246,000). For men, the largest sector by far was "Manufacturing" (n=470,000), although large numbers of men were also employed in "Trade" (n=238,000) and "Accommodation and food services" (n=208,000).

The patterns of shift work in Canada vary considerably between men and women as well as between industries. It is important to understand the patterns and trends in shift work to design studies, predict health impacts, and target efforts to prevent or mitigate any adverse health effects.

Presenter Biography

Paul Demers is a Professor and the Director of the University of British Columbia’s School of Environmental Health. He is an epidemiologist whose research has primarily focused on occupational cancer, lung disease, and heart disease. His recent epidemiologic studies have included an examination of the impact of air pollution on child health and several retrospective cohort studies of firefighters, paramedics, aluminum smelter workers, and sawmill workers. He has been a member of various International Agency for Research on Cancer (IARC) Working Groups for the Evaluation of Carcinogenic Risk to Humans, including the working group that evaluated shift work in 2007. He is the director of the CAREX Canada project, a national occupational and environmental hazard surveillance program funded by the Canadian Partnership against Cancer and will be presenting shift work data from that project at this symposium. Paul has just accepted an offer to become the new director of the Occupational Cancer Research Centre in Toronto.



Demers PA, Wong I, McLeod C



 Occupational Cancer Research CentreInstitute for Work & Health | Research Excellence Advancing Employee Health