Shift work ‘increases coronary artery disease risk’

Shift work has a harmful effect on cardiovascular function, with the risk of developing coronary artery disease increasing the longer an employee carries out this type of work, research has found.

Shift workers were found to be 13% more likely to develop coronary artery disease – sometimes called ischaemic heart disease – than daytime workers, while there was a 0.9% increase in the chance of a diagnosis with every year spent in this working pattern.

Disturbances to circadian rhythms and increased stress, affecting normal metabolic and hormonal functions, are potential reasons for the increase in coronary artery disease diagnoses among shift workers, the researchers from Huazhong University of Science and Technology in China suggested.

Unhealthy lifestyle choices such as smoking, poor diet and lack of physical exercise were also more common among shift workers.

The research, Shift work and ischaemic heart disease: meta-analysis and dose–response relationship – which has been published in the journal Occupational Medicine – analysed 21 studies involving 320,002 participants, of whom 19,782 had coronary artery disease.

Study author Professor Man 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 health care systems.

“Shift work 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 shift work 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.”