(HealthDay News) – Shift work correlates with an increased risk of vascular events, according to a review published online July 26 in BMJ.

Manav V Vyas, from Western University in London, Canada, and colleagues conducted a systematic literature review and meta-analysis to examine the association between shift work and major vascular events. Thirty-four observational studies involving 2,011,935 individuals were identified.

The researchers found that shift work correlated significantly with myocardial infarction (risk ratio, 1.23) and ischemic stroke (risk ratio, 1.05), with no between-study heterogeneity. There was also an increased risk of coronary events (risk ratio, 1.24), although there was considerable heterogeneity between studies (I²=85%). The pooled risk ratios were also significant after adjustment for risk factors. With the exception of evening shifts, all shift work schedules correlated with a significantly higher risk of coronary events. There was no correlation between shift work and increased rates of mortality (vascular cause specific or not). Adjustment for smoking and socioeconomic status was not a source of heterogeneity in the primary studies. On the basis of a 32.8% prevalence of shift work in Canada, the shift work-related, population attributable risks were 7% for myocardial infarction, 7.3% for all coronary events, and 1.6% for ischemic stroke.

“The increased risk of vascular disease apparent in shift workers, regardless of its explanation, suggests that people who do shift work should be vigilant about risk factor modification,” the authors write. “More work is needed to identify the most vulnerable subsets of shift workers and the effects of shift modifying strategies on overall vascular health.”

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