In a recent review, researchers analyzed data from 34 studies to determine the association between shift work and vascular events. The study designs varied-11 were prospective cohort trials, 13 were retrospective studies, and 10 were case-control analyses-as did definitions of shift work: subjects worked a variety of shifts, including evening, mixed, night, and rotating shifts. Some studies didn't specify the type of shift. Of the 34 studies, which involved a total of 2,011,935 people, 30 compared data between shift workers and day workers; the other four used the general population as the control group.

Results of a pooled random-effects analysis showed that shift work was associated with increased risks of myocardial infarction (risk ratio, 1.23), coronary events (risk ratio, 1.24), and ischemic stroke (risk ratio, 1.05). The authors also examined cardiovascular events and coronary, cerebrovascular, cardiovascular, and all-cause mortality, although no significant associations were seen.

The authors, noting that this review is the largest conducted to date that examines the relationship between shift work and vascular events, also note that the studies used differing outcome definitions, which may have led to differences among study results.

Although causality cannot be determined from observational studies, the results of this analysis show an increased risk of vascular events among shift workers. The authors recommend that people doing shift work be made aware of modifiable risk factors and adjust accordingly. They should also be mindful of cardiovascular symptoms indicative of disease to proactively address any potential issues.

Reference