Authors: Ellen Clarke
A new preliminary study has revealed that daylight saving time may temporarily increase risk of ischemic stroke. The results of the study are due to be presented at the American Academy of Neurology’s 68th Annual Meeting (15 – 21 April, Vancouver, Canada).
Ischemic stroke, which accounts for 87% of all strokes, occurs as a result of a clot blocking blood flow to the brain.
“Previous studies have shown that disruptions in a person’s circadian rhythm, also called an internal body clock, increase the risk of ischemic stroke, so we wanted to find out if daylight saving time was putting people at risk,” explained author Jori Ruuskanen, from the University of Turku (Finland).
The team of researchers utilized ten years of data for stroke in Finland to compare the rate of stroke before and after a daylight saving time transition. The rate of stroke in 3033 people who were admitted to hospital during the week following a daylight saving time transition was compared with the rate of stroke in a group of 11,801 who were admitted to hospital either two weeks preceding or two weeks following that week.
Overall, the rate of ischemic stroke was found to be 8% higher during the first two days following a daylight saving time transition, in contrast to the next two days, where no difference was observed.
The study also indicated that certain groups had an increased risk of stroke following daylight saving time than any other period, including cancer patients, who were 25% more likely to experience stroke, and individuals over the age of 65, who were 20% more likely to have a stroke directly after the transition. Hospital deaths from stroke did not increase however in the week following 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,” commented Ruuskanen.