The adverse effects of shift work have been the subject of many articles, scholarly reports and studies


The adverse effects of shift work have been the subject of many articles, scholarly reports and studies

The Institute for Health and Work (Canada)

Shift work and health

Shift work — employment with anything other than a regular daytime work schedule — makes up a large part of work in the Canadian economy. For at least 50 years, researchers have been exploring the question of whether working shifts poses a health hazard. This note summarizes the findings of a selection of this research, including several articles that have reviewed aspects of this literature.

What is the research telling us?

The Institute for Work & Health has scanned the research and called on experts to get the latest word on what we know – and don’t know – about the effects of shift work on employee health. There are certainly areas for concern, so more research on ways to protect shift workers is the logical next step.

The risk of injury

A study from the Institute for Work & Health—published in the January 2013 issue of Occupational & Environmental Medicine—found that about 12 per cent of work injuries experienced by women and six per cent of work injuries experienced by men were attributed to the higher risk of work injury during evening, night and early morning hours.

Poorer health outcomes

A study by the Institute for Work & Health compared the health outcomes of injured workers in standard day shifts with those of injured workers in non-standard shifts. The study found injured workers in non-standard shifts reported poorer health scores two years after an injury and that injured shift workers were not more likely than injured day workers to leave their jobs or change out of their shifts.

Health research update

Research on the health effects of shift work has continued to grow over time. There is a relatively large literature on possible connections between shift work and several aspects of workers’ health. In some of these areas, the research findings clearly point to an elevated risk of adverse health outcomes arising from shift work.

Probable cancer risk

Night-time shiftwork has been classified as ‘probably carcinogenic to humans’ by the International Agency for Research on Cancer. Approximately 18.5% of the working population in Canada (nearly 2.8 million workers) work a regular evening shift, graveyard shift, or rotating (both days and nights) shift.

In the news

Rotating night shifts tied to heart disease risk

Scientific American - 27 April 2016

Chronic cognition impairment

Shift work chronically impairs cognition, with potentially important safety consequences not only for the individuals concerned, but also for society. So says a 2014 report published in Occupational and Environmental Medicine, and international peer-reviewed journal in all aspects of environmental and occupational medicine.

Hazards of rotating shift work

In 2007 the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption. In a study in the American Journal of Preventive Medicine, researchers found that women working rotating night shifts for 15 or more years appeared to have a modest increase in lung cancer mortality.

Risk of medical error

Studies on diagnostic error in emergency medicine have shown error rates between 1 and 12%, and it’s been suggested that cognitive error, or some flaw in the decision making process (as apposed to a lack of knowledge), is present in about 95% of these cases.

Major health consequences

The 15 million Americans who work the night shift won't hesitate to tell you about the toll their work lives take on their sleep schedules. However, quality shut-eye isn't the only thing at risk when it comes to a shift worker's health -- especially among women working rotating night shifts, according to a new study.

Shift work linked to diabetes

A recent study found that retired shift workers were more likely than non-shift workers to report having diabetes. According to the researchers, shift work can disrupt sleep cycles, which has been found to negatively affect the body's ability to use glucose — a key trait of diabetes.

Shift work ages your brain

A new study shows hourly shift work might have serious implications for your brain. The study in Occupational & Environmental Medicine looked at more than 3,000 people living in France, half of whom had worked shifts. Those who had done so had lower scores on memory tests, processing speed and overall brain power.

More resources

US Nat. Library of Medicine

Sleep Management Institute

Sleep Education