Canadians who work night and rotating shifts are almost twice as likely to be injured on the job than those working regular day shifts, according to a study by researchers at the University of British Columbia.

The study, published in the current issue of the Scandinavian Journal of Work, Environment and Health, examined data on more than 30,000 Canadians collected as part of Statistics Canada’s Survey of Labour and Income Dynamics and compared results between workers involved in different types of shift work from 1996-2006. It shows that while the overall rate of work injuries in Canada decreased during this time, the rate of injuries did not decline for night shift workers.

The study also found that the risk of work injury associated with shift work was more pronounced for women, especially if they work rotating shifts.

“The disruption of normal sleep patterns due to shift work can cause drowsiness or fatigue, which can lead to workplace injuries,” says Imelda Wong, a PhD Candidate at UBC’s School of Environmental Health and the study’s lead author. “Our research shows that people working rotating and night shifts are more likely to experience an injury than those who work regular day hours.”

The researchers suggest that because women are more likely to be responsible for childcare and household work, they may have more difficulties adjusting to shift work and maintaining regular sleep schedules.

The number of Canadians working non-standard hours has increased dramatically in recent decades.  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.

In 2006, 307,000 work-related injury claims associated with shift work represented more than