Transition to Daylight Savings Time Temporarily Increases Stroke Risk

ischemic stroke
ischemic stroke
Increased incidence of ischemic stroke during first two days after transition to daylight saving time

HealthDay News – Supporting the concept that disruptions in internal circadian rhythm can increase the risk for stroke, a study to be presented at the annual meeting of the American Academy of Neurology in Vancouver, Canada found that the transition to daylight saving time (DST) is associated with a transient increased risk of ischemic stroke.

Jussi Sipilä, from the Division of Clinical Neurosciences, Turku University Hospital, Finland, and colleagues examined the effects of DST transitions on stroke hospitalizations and in-hospital mortality in Finland in 2004 to 2013. They compared incidence ratios for 3,033 patients hospitalized during the week following DST transition with expected incidences for 11 801 patients hospitalized 2 weeks before or 2 weeks after the index week.

The researchers found that the incidence of ischemic stroke was increased during the first 2 days after transition (incidence ratio, 1.08; 95% confidence interval, 1.01 to 1.05); the difference was attenuated during observation of the whole week (incidence ratio, 1.03; 95% confidence interval, 0.99 to 1.06). 

Compared with men, women were more susceptible to temporal changes after DST transitions, with no difference in overall risk of ischemic stroke between genders. The risk was increased for patients with malignancy, and advanced age (>65 years) correlated with increased risk on the first 2 days and second day after DST transition.

Hospital deaths from stroke did not increase in the week after a daylight saving time transition.

“Further studies must now be done to better understand the relationship between these transitions and stroke risk and to find out if there are ways to reduce that risk,” a coauthor said in a statement.


Sipilä JOT, Ruuskanen J, Rautava P, Kytö V. Daylight Saving Time Transitions, Incidence and In-hospital Mortality of Ischemic Stroke. Presented at: American Academy of Neurology Annual Meeting 2016. April 15-21, 2016. Vancouver.