Shift work
Working night shifts could have a negative impact on your health.

Working irregular or rotated shift patterns, especially at night, could have a detrimental effect on a person's health.

Research carried out by an international team has linked shift work with an increased risk of major vascular problems, such as heart attacks and strokes.

The study, published on BMJ.com (the British Medical Journal), represents the largest analysis of shift work and vascular risk to date, and its authors say it has implications for both public policy and occupational medicine.

Scientists from Canada, Norway and Sweden analysed the results of 34 studies, representing around 2 million people, to see what effect irregular or unspecified shifts, night shifts and rotating shifts could have on health.

Of the people studied, 6,598 suffered a heart attack, while 1,854 had an ischaemic stroke caused by a lack of blood flow to the brain.

It was found that these events were more commonly suffered by shift workers, who had a 23 percent increased risk of a heart attack, a 24 percent increased risk of a coronary event and a 5 percent increased risk of a stroke.

Night shifts were found to bring the steepest increase in heart attack risk, of some 42 percent. But the study found no increased risk of death in any case.

While the authors admit that the study did not find a major correlation, they concluded it was strong enough to prompt further analysis. Statistical research on Canadian patients during 2008-09 concluded that 7 percent of heart attacks, 7.3 percent of coronary events and 1.6 percent of strokes could be attributed to shift work.

"The increased risk of vascular disease apparent in shift workers, regardless of its expanation, suggests that people who do shift work should be vigilant about risk factor modification.

"Shift workers should be educated about cardiovascular symptoms in an effort to forestall or avert the earliest clinical manifestations of disease."

The authors add that the "modification and rationalisation of shift schedules may yield dividends in terms of healthier, more productive workers."