Does shift work lead to more injuries?
In my previous blog I discussed the indisputable fact that working extended hours causes worker fatigue and lowers performance. This was regardless of the time of day that was worked. Another aspect to consider is the effect of shift work on worker performance. I will define shift work as either the night shift or rotation shifts working normal amount of work hours (8-10 hours/shift). A recent study of Canadian workers shows some interesting results in regards to work injuries. The study covered a 10 year period, 1996-2006, and examined the injury rates of workers differentiated by the shift worked and by gender. The results were as follows:
- Rate of work injury decreased overall between 1996–2006, but not for night shift workers
- Night shift work was associated with work injury for women
- Rotating shift work was associated with work injury for women
- Excess risk of work injury attributed to shift work was 14.4% for women and 8.2% for men
The study concluded that “rotating and night shift workers appear to have a higher risk of work injury, particularly among women.” The greater risk among women may be explained by the difficulty of balancing shift work and life. Studies that have examined the sleep length of men and women night shift workers found that women with children had shorter sleep lengths than men. This leads to chronic sleep disruption, especially during non-shift work days. This results in greater fatigue, lower levels of alertness and job performance.
Why It Matters
Given that studies continue to show that fatigue has a negative effect on worker health and safety it is paramount that the design of the work systems and environment take these facts into account. There needs to be redundancies built into the system so that errors and injuries are very difficult at best to occur. This can be accomplished through the use of Human Factors/Ergonomics will additional controls through policies that support health and well-being of the worker.
Wong IS, McLeod CB, Demers PA. Shift work trends and risk of work injury among Canadian workers. Scand J Work Environ Health. 2011