Working the night shift isn't just annoying; it might actually leave you at increased risk for injury.
A new study by researchers at the University of British Columbia has found that Canadians who work night shifts and rotating shifts are almost twice as likely to be injured on the job than those working regular day shifts.
The researchers also found that female night workers were more prone to injuries than male workers, especially if they worked rotating shifts.
The study, published in the Scandinavian Journal of Work, Environment and Health, was written by Imelda Wong, a PhD Candidate at UBC's School of Environmental Health.
Wong says she became interested in the health effects of night work after the International Agency for Research on Cancer (the cancer arm of the World Health Organization) reported in 2007 that those who work graveyard shifts appear to have an increased risk for all types of cancer.
Wong and her team decided to look at what other health effects are caused by night work. They looked at data on more than 30,000 Canadians from Statistics Canada's Survey of Labour and Income Dynamics. They compared results between workers involved in different types of shift work from 1996-2006.
They found that while the overall rate of workplace injuries in Canada fell during the study period, the injury rate for night shift workers didn't drop.
As for why that might be, Wong says it likely comes down to sleepiness.
"I think we can all relate to what it feels like to have a sleepless night. We feel a bit groggy the next day," she told CTV's Canada AM Wednesday from Vancouver. "Well, people who work shift work are constantly sleep-deprived and may be more fatigued at work and that does increase the risk of injury."
She says her study looked at both people who worked regular night schedules, and people who worked rotating schedules.
The study found that the risk of injury on the job associated with shift work was more pronounced for women, especially if they worked rotating shifts.
"We found with women the risk of injury was more pronounced with both rotating and regular night shift workers, and for men, the risk was highest among those who worked regular night shifts," she said.
The researchers suggest that because women tend to be responsible for child care and household work, they have more difficulty maintaining regular sleep schedules.
"On average, women spend nine hours more per week on household duties than men. And women's primary household duties include child care, which involves daily activities that require more alertness," Wong noted.
As Canada has become a 24-hour society, the number of Canadians working non-regular hours has increased dramatically. The number of women in rotating and night shift work increased by 95 per cent during the study period, primarily in the health care sector. For men, the increase was 50 per cent, mostly in manufacturing and trades.
All those injuries add up and cost society in real dollars, the study found.
In 2006, there were 307,000 work-related injury claims linked to shift work. All told, they represented more than $50.5 million in costs to Canada's workers' compensation system.
The authors conclude that both employers and governments need to "consider policies and programs to help reduce the risk of injuries among shift workers."
