Shift workers are at a higher risk of injury when switching schedules: Report
Shift workers are at a higher risk for injuries when switching shifts — even when that change is from non-standard work hours to regular day shifts, according to a recent study by the Toronto-based Institute for Work and Health (IWH).
For Better or Worse? Changing Shift Schedules and the Risk of Work Injury Among Men and Women used data from Statistics Canada’s Survey of Labour and Income Dynamics to examine work schedule patterns over a six-year period among a representative sample of about 19,000 Canadian workers.
The study reviewed three of the survey periods — 1999-2004, 2002-2007 and 2005-2010 — and collecting data surrounding injuries leading to more than one week’s absence from work or a receipt for workers’ compensation.
It concluded that while employees working evening and night shifts are more likely to be injured on the job when compared to their counterparts working day shifts, employees switching between shift schedules are at an even higher risk.
This includes employees who move from irregular evening or night shifts to a regular, daytime schedule.
"That was surprising and seemed a bit counterintuitive to me because we generally think that working a regular daytime shift is better for workers in terms of better sleeping habits and better work-life balance and that might relate to reduced risk for work injury," said Imelda Wong, study author and board member of the Shiftwork and Working Time Society of the International Commission on Occupational Health.
"But we didn’t find that. I’m hoping that the study will raise awareness and generate discussion about why changing a shift schedule doesn’t necessarily equate to reducing the risk for injury. I’m very much interested in continuing this line of research on shift work and how it may affect health and safety in workers and even how it may affect their family and work-life balance."
The IWH estimates as many as 30 per cent of Canadians work schedules outside of conventional daytime hours. Because many biological functions follow a circadian rhythm — the natural cycle that promotes activity during daylight hours and recovery at night — continuous activity during normal sleeping hours can lead to circadian desynchronization, according to the institute.
Sleeping, waking, digestion, secretion of adrenalin, body temperature, blood pressure and pulse are some of the critical functions regulated by the 24-hour cycle, according to the Canadian Centre for Occupational Health and Safety (CCOHS). The disruption of the circadian rhythm can also interfere with the medical treatment of some diseases.
Long-term side effects include increased fatigue and poor concentration, according to CCOHS Shift work is associated with the human error connected with nuclear power plant incidents, air crashes and other catastrophic events.
While regular daytime schedules are widely thought to be the best when it comes to promoting healthy circadian rhythms, the IWH study found the disruption of biological patterns caused by the switch from one shift to another — even from irregular shifts to a daytime schedule — is significant enough to increase a worker’s risk for injury.
The study also found workers who changed shifts were generally younger and had lower levels of education and income — factors that have been associated with an increased risk of work injury in previous studies.
"I’m hoping what people who read the paper take home from this is that the results suggest the need to implement occupational health and safety programs soon after a change in shift schedule in whichever direction," Wong said.
"Results also highlight the importance of greater awareness of health and safety actions on an ongoing basis."
Better programs needed
Jean-Pierre Fortin, national president of the Customs and Immigration Union (CIU-SDI), said better programs and policies concerning shift work are crucial not only to employee safety but to public safety as well.
"We are in the law enforcement field and like any police forces in Canada, we do work on rotation shifts," Fortin said.
"We’re talking about people who have powers of arrest, who are armed at the border. So, obviously, for somebody who is doing a lot of shift work, a lot of rotations and a lot of overtime, it could impact our ability to perform our duties in the long run."
As a result, the union has been pushing hard in recent rounds of bargaining to allow employees access to their pension — with no penalty — after 25 years’ service, he said, citing studies that have proven the ways in which persistent shift work reduces not only quality of life but also life expectancy.
"The time that you were doing those long shifts, at the end you were exhausted," Fortin said. "This is a fact that’s been proven throughout many studies, that it reduces your expectation of life."
In addition to allowing employees to access their pension when they are no longer capable of maintaining rotating shifts, CIU-SDI is also calling for more flexibility in the negotiation of shift schedules.
Giving employees more control over their schedules — and encouraging them to maintain their personal health outside of work, such as with employee gym memberships — will positively impact workers’ health and reduce the risk of workplace injuries.
While employers may not be able to provide all of these improvements, even the smallest of adjustments can have an impact. CCOHS recommends shifts rotate forward from day to afternoon to night because circadian rhythms adjust more easily when moving ahead than when moving back.
The provision of certain facilities — including those for rest and socialization — can also help employees cope with shift schedules.
"There isn’t really one solution because each industry — and even workplace — is unique with very different circumstances," Wong said.
"I hope studies like mine create opportunities for employers and employees to discuss options to help fund a solution that works for their particular situation."
