Workers Changing to/from Shift Work Face Highest Risks of Injury


Countless studies have shown that employees working evening, night or rotating shifts face a higher risk of being injured on the job than those who work days.

But according to a study by Dr. Imelda Wong at the Institute for Work & Health (IWH), the ones facing the highest risks are those who change from day jobs into shift work and who change out of shift work into days. (Note: The study refers to permanent or indefinite shift changes, not those linked to rotating shift work.)

“This is surprising because we expected that moving into a daytime job may improve sleep and create a better work-life balance, thereby reducing the risk of work-related injury,” said Wong. “But we found that people who switch from nights to days are still two-and-a-half times as likely to get injured as those who have always worked days.”

The researchers used Statistics Canada’s Survey of Labour and Income Dynamics, focusing on three survey periods: 1999 to 2004; 2002 to 2007; and 2005 to 2010. Receipt of workers’ comp or a work injury requiring more than seven days’ away from work was used as the indicator of work-related injury.

The analysis looked at four categories of workers:

  • Those who only work days;
  • Those changing from days to non-standard shifts;
  • Those changing from shifts to days; and
  • Those working non-standard shifts the entire time.

The study found that, compared to day workers, long-term non-standard shift workers were 1.5 times more likely to be injured. But the risks were even greater for those changing work schedules, whether to or from shift work.

Those changing from day shifts into non-standard shifts were 2.6 times more likely to get hurt at work, while those changing into day shifts were 2.4 times more likely.

The study didn’t determine, however, why the risk of sustaining work injury among shift workers remains high even after they change to daytime work.

“At this time we can only speculate on what may be contributing to an elevated risk for those who switch from nights to days,” says Wong. “Still, I think this study tells us we need health and safety policies and programs for people who have made a change in shift schedules. It’s important to pay attention to health and injury risks even after someone has stopped working nights and moved into days.”

Source: At Work, Issue 78, Fall 2014: Institute for Work & Health, Toronto

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