Shift work disturbs the body's natural clock
(circadian rhythm), which in turn affects the work life equilibrium. This can
result in a variety of health problems such as increased cholesterol and high
blood pressure. Vascular ailments are caused by hardening of arteries
(atherosclerosis) due to plaque deposition.
Recently, Manav and colleagues conducted a
systemic review to assess the link between shift work and vascular events. For
the review 34 observational studies in 2,011,935 individuals were identified.
"Study quality was assessed with the Downs and Black scale for observational
studies. The three primary outcomes were myocardial infarction, ischemic
stroke, and any coronary event."
The scientists noticed that shift work is
considerably linked with ischemic stroke and myocardial infarction. The risk
ratio with myocardial infarction was 1.23 and with ischemic stroke was 1.05.
The scientists reported that in contrast to
daytime workers, the shift workers had 24 percent high risk for coronary
ailments, 5 percent high risk for stroke and 23 percent high risk for heart
There was no association between raised
mortality rates and shift work. Adjustment for socioeconomic status and smoking
was not a cause of heterogeneity.
In Canada the occurrence of shift work is
32.8 percent and the risk for myocardial infarction were 7 percent, for
ischemic stroke the risk was 6 percent and for coronary events the risk was 7.3
The researchers said, "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."
They further added, "More work is needed
to identify the most vulnerable subsets of shift workers and the effects of
shift modifying strategies on overall vascular health."
The experts said that the relative risks were
modest but because of the rising frequency of shift work among the general
population, the consequences on the public health are not insignificant.
Scientists call for further researches to
analyze the most affected shift workers and to assess how the overall vascular
health is influenced by the pattern of shift.
Shift work and vascular events: systematic
review and meta-analysis; Manav Vyas et al; BMJ 2012; 345 doi: