Ischemic stroke occurs when a blood clot blocks the flow of blood through a narrow artery to the brain. This triggers a major medical emergency as the brain quickly becomes deprived of necessary oxygen and nutrients. While there are many factors which can contribute to your stroke risk, researchers have recently found that one somewhat unexpected factor—your blood type—could make you 16 percent more likely to experience a stroke before the age of 60. Read on to learn whether you’re at heightened risk, and if so, how you can mitigate it.
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Established research has already shown that your blood type and stroke risk are linked, but the association appeared to be minimal. Now, a new study published in the Aug. 2022 issue of the journal Neurology says the association is strongest when you look at blood type and early strokes—those occurring before age 60—in particular.
That team conducted a meta-analysis of 48 studies on genetics and ischemic stroke. Their subject pool included 17,000 individuals who had previously had a stroke, as well as nearly 600,000 healthy people who had never had a stroke. They then looked to identify genetic variants associated with stroke risk. Ultimately, they were able to establish a link between early stroke and blood type.
However, the scientists behind the study say they still don’t know why this particular blood type would cause higher risk. “It likely has something to do with blood-clotting factors like platelets and cells that line the blood vessels as well as other circulating proteins, all of which play a role in the development of blood clots,” Steven J. Kittner, MD, MPH, Professor of Neurology at UMSOM and a neurologist with the University of Maryland Medical Center, told Medical News Today. “We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk,” he added.
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The Neurology study determined that people who experienced early stroke were more likely to have type A blood than those who did not have a stroke, or had a stroke later in life. In fact, these individuals were 16 percent more likely than others to experience a stroke before age 60.
Both those who experienced early and late stroke were also more likely than average to have type B blood, though the association was less pronounced for this group.
The researchers also looked at which group was most protected from stroke based on blood type, and found that individuals with type O blood—the most common blood type—had a 12 percent lower than average risk of stroke, compared with the other blood types.
Incidence of stroke increases significantly with age, “doubling for each decade after age 55,” according to a 2011 study published in the medical journal Neurotherapeutics.
However, those under 60 are at increasing risk, experts say. “The number of people with early strokes is rising. These people are more likely to die from the life-threatening event, and survivors potentially face decades with disability. Despite this, there is little research on the causes of early strokes,” Kittner told Medical News Today.
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The researchers emphasized that your blood type should not be any major cause for concern when it comes to your stroke risk. “People with blood type A should not be worried,” said researcher Braxton Mitchell, a professor at the University of Maryland School of Medicine. That’s because there are many ways to lower your stroke risk significantly. These include quitting smoking, exercising regularly, eating a healthy diet, maintaining a healthy weight, and managing any underlying health conditions, including diabetes, high blood pressure, high cholesterol, and heart disease. Speak with your doctor for more information on how you can lower your stroke risk.