Shift work and health

About one-quarter of full-time working Canadians aged 19 to 64 worked shifts in 2005, according to data from Statistics Canada’s General Social Survey. Shift work—essentially anything other than a regular daytime work schedule—makes up a large part of the Canadian economy.

Why study shift work?

Shift work is not without health risks. For at least five decades, researchers have been exploring whether working shifts poses a safety and/or health hazard.

Researchers have found that shift workers, particularly those working nights, face a higher risk of getting hurt on the job than regular day workers. They have also found that shift work is associated certain health problems.

For example, studies have shown long-term night shift workers have an elevated risk of breast cancer and a potentially elevated risk of colorectal cancer. Higher risks of gastrointestinal disorders, mental health problems (including depression) and preterm delivery during pregnancy have also been indicated among shift workers.

The health effects of shift work

Researchers at the Institute for Work & Health (IWH) are interested in learning about the health hazards related to shift work. In April 2010, IWH joined with the Occupational Cancer Research Centre (OCRC) to co-host a symposium on this topic. The goal of the symposium was to address the strength of the research evidence on the role of shift work in cancer, cardiovascular disease, sleep disturbances, work injuries and pregnancy outcomes.

IWH has also published a number of other reports and articles on the health effects of shift work.

Related OCRC resources on the effects of shift work on injury and health are also available.

Interventions to decrease the health effects of shift work

Having explored health and safety hazards related to shift work, IWH and OCRC teamed up again to explore ways to mitigate these hazards. A second symposium was held in November 2012. Led by OCRC and co-hosted by IWH, the symposium sought to extend previous discussions of injuries and illnesses related to shift work to promising interventions for prevention.