Shiftwork increases heart disease risk

Shiftworkers are 13% more likely to develop ischaemic heart disease compared with daytime workers and their risk of contracting heart disease increases 1% annually. This is according to a large study recently published in the journal Occupational Medicine.

Ischaemic heart disease is caused by narrowed heart arteries. Also known as coronary artery disease, ischaemic heart disease is the leading cause of death in many parts of the world.

For this research on the risk of ischaemic heart disease in shiftworkers, researchers analysed 21 studies, which pooled together 320,002 participants with 19,782 cases of ischaemic heart disease. Shiftworkers were found to be 13% more likely to develop ischaemic heart disease compared with daytime workers. 

The study authors specifically looked at how the risk changes over time and found that there was a 0.9% increase in the chance of developing ischaemic heart disease with every year spent in this working pattern. Shiftwork is a very common working pattern and consists of irregular or unusual hours of work such as rotating shifts, evening work or night work.

The exact reason why shiftworkers are developing ischaemic heart disease is not known for certain, but it is felt that disruption of the normal sleep-wake cycle, the increased stress involved in shiftwork and unhealthy lifestyles often associated with shiftwork, could be contributing.

The study authors have called for employers of shiftworkers to do more to protect their employees’ health.

Study author Professor Chen said: “The number of deaths due to ischaemic heart disease has continued to rise, with 7.6 million deaths in 2005 and 8.9 million people dying due to the condition in 2015. Patients can require surgical interventions and medications meaning ischaemic heart disease is one of the biggest burdens on healthcare systems.

“This study summarised previous studies and drew a positive conclusion that shiftwork contributes to the incidence of ischaemic heart disease. The longer an employee spends working shifts, the higher their risk of developing ischaemic heart disease.

“Shiftwork is a timesaving work system, it can earn more profit but it can also cause harm to the health of employees, so employers should reduce shiftwork as much as possible.

“Employers should pay attention to staff members who are experiencing symptoms of heart problems as well as those with a family history of heart disease. Employers could provide health promotion, such as information on how to prevent and deal with ischaemic heart disease. Companies could also consider providing health checks to detect early signs of heart problems.”

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