According to new research, working in shifts has a negative impact on cardiovascular health.
The Chinese study, which was published in the journal Occupational Medicine, observed more than 320,000 shift workers. They found that:
- Shift workers have a heightened risk of heart disease; and
- The risk increases the longer shifts are worked.
While the study was not designed to prove cause and effect, the data showed that shift workers were 13% more likely to develop coronary heart disease than daytime workers.
Largest ever study
Dr Weihong Chen, the study’s lead author, claims: “This is the largest study about shift work and ischemic heart disease ever undertaken”. Data was analysed from 21 previous studies involving hundreds of thousands of people and nearly 20,000 cases of coronary heart disease. Coronary artery disease, also known as ischaemic heart disease, is the leading cause of death in many parts of the world.
Dr Chen’s analysis of the prior studies draws a positive conclusion that shift work contributes to the incidence of ischaemic heart disease. Dr Chan says “The longer an employee spends working shifts, the higher their risk of developing ischaemic heart disease”.
Chinese researchers additionally found that every year spent working on shifts adds nearly 1% to the risk of coronary heart disease. The exact reason shift workers are developing ischaemic heart disease is not known for certain but the disruption of the normal sleep-wake cycle, the increased stress involved in shift work and unhealthy lifestyles associated with shift work are felt to be contributing.
The exact reason shift workers are developing ischaemic heart disease is not known for certain but the disruption of the normal sleep-wake cycle, the increased stress involved in shift work and unhealthy lifestyles associated with shift work are felt to be contributing.
Reduce shift work
Dr Chen comments: “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”.
Dr Chen stresses employers need to be more proactively involved in their employees’ health by:
- Paying attention to staff experiencing heart problem symptoms – as well as those with a family history of heart disease;
- Providing health promotions – such as how to prevent and deal with heart disease; and
- Considering health checks to detect early signs of heart problems.
Dr Chen is a researcher in occupational and environmental health at Huazhong University of Science and Technology in Wuhan.
In 2007, the World Health Organisation classified night shift work as a probable carcinogen/cause of cancer due to the way it disrupts a person’s body clock.