A person’s blood type is associated with a greater or lesser risk of premature stroke before the age of 60, a new US scientific study shows.
Group 0 has the lowest risk of early stroke before age 60, while A has the highest. This finding may lead to new methods of predicting and preventing strokes in young adults, which are increasingly occurring at these ages.
Researchers at the University of Maryland School of Medicine, led by professors Braxton Mitchell and Stephen Kittner, who published in the journal Neurology of the American Academy of Neurology, evaluated data from 48 studies involving a total of nearly 17,000 people with ischemic stroke (of which 5,825 before 60) and 576,353 without stroke.
The study (meta-analysis) shows that people with blood type A have a 16% higher risk of early stroke before the age of 60, while those with type 0 have a 12% lower risk of early stroke, compared to other blood types.
“Non-O blood types have previously been linked to a risk of early stroke. Our meta-analysis findings show a stronger association between these blood types and early stroke than stroke after age 60, and the risk is mostly for blood type A.”Mitchell said.
The researchers found that:
- People who had a stroke before the age of 60 were more likely to have type A blood and less likely to have type 0, compared to those who had a stroke after 60 and those who had never had a stroke.
- 48% of people with an early stroke had type A blood compared to 45% of those who had a stroke after age 60 and 44% of those who never had a stroke.
- 35% of people with a stroke before 60 had blood type O compared to 39% of people with a stroke after 60 and 41% of those who never had a stroke.
The researchers pointed out that the increased risk for blood group A is however very small and those with this group should not worry that they have a high probability of having an early stroke, nor do they need to bother with extra medical tests for no reason.
“We don’t yet know why blood group A has a higher risk, but it probably has to do with blood clotting factors such as platelets and cells on the surface of blood vessels, as well as proteins circulating in the blood that play a role in clot development”said Dr. Kittner.
Previous studies have shown that people with blood type A have a slightly higher risk of developing blood clots in the legs (deep vein thrombosis).