Early-onset strokes more common among those with type A blood
Your blood type might indicate whether you are at a higher risk of suffering from a stroke before you turn 60, according to a new analysis from the University of Maryland School of Medicine.Read More »
Researchers came to this conclusion after studying all data available in genetic studies of young adults who suffered ischemic strokes. Such strokes take place when the flow of blood to the brain is blocked.
More likely to have blood type A
The study found that those who suffer an early-onset stroke (one that takes place before the age of 60) are more likely to have blood type A than blood type O, the most common blood type, says study author Dr. Braxton D. Mitchell who is a professor of medicine at the University of Maryland School of Medicine.
Those who suffered both early and late strokes were more likely also to have blood type B, but the link with blood type A was found more strongly only in those younger than 60.
Those who possess the gene variants in those blood types might have a greater likelihood of developing blood clots—which can lead to their suffering a stroke.
The link between blood types and strokes that occur later in life is a lot weaker than the link between strokes suffered earlier in life, Mitchell adds.
No reason for concern
The researchers point out that the increased risk is relatively low. Those with type A blood should not worry about suffering from an early-onset stroke. They also should not undergo medical testing or additional screening based on this finding.
Scientists still are not sure why blood type A would mean a higher risk of early-onset stroke, explains Dr. Steven J. Kittner, professor of neurology at the University of Maryland School of Medicine. It likely involves blood-clotting factors such as cells that line the blood vessels and platelets. Other circulating proteins which play a role in the development of blood clots also are involved.
Blood clots in legs
Earlier studies have suggested that people with type A blood have a slightly greater risk of developing blood clots in their legs, known as deep vein thrombosis.
More studies clearly are needed to make clear the mechanisms behind the increased stroke risk in these people, Kittner adds.
Cases are increasing
The research is needed because the number of people who suffer strokes early in life is growing, Kittner explains. Many are likely to die from such a life-threatening event, while those who survive face decades of having to live with a disability. Nevertheless, until now little research has been conducted on the causes of these early strokes.
The results deepen scientists’ understanding of how early onset strokes take place, says Dr. Jennifer Juhl Majersik of the University of Utah and Fellow of the American Academy of Neurology, who wrote an editorial that accompanies the study. Future research is needed to understand more precisely how strokes develop, she explains.
Treatments could be developed
As the causes of early onset strokes are found, treatments could be developed to prevent them, Majersik adds.
The result could mean that those who are prone to the strokes would suffer less disability during the years in which people are at their most productive.
How study was conducted
The researchers looked thoroughly at 48 studies on ischemic stroke and genetics of 17,000 stroke patients and compared them with almost 600,000 healthy patients in a control group who never had experienced a stroke.
They searched all the gathered chromosomes to spot genetic variants linked to a stroke. They found an association between early-onset stroke and the region of the chromosomes that included the gene that determines whether a blood type is A, AB, B, or O.
The finding was that those who had blood type A had a 16% higher risk of having an early-onset stroke than those who had blood type O. Those who had blood type O had a 12% lower chance of suffering a stroke than people with other blood types.
The analysis is published in the journal Neurology.