Researchers have found that people with type A blood are more likely to have a stroke before the age of 60 compared to people with other blood types.
blood types Describe the rich set of chemicals displayed on the surface of red blood cells. Among the most common are those named A and B, which can exist together as AB, individually as A or B, or not exist at all, as O.
Even within these major blood groups, slight differences arise from mutations in the genes responsible.
Now, genomic research has revealed a clear link between the subgroup A1 gene and early stroke.
The researchers pooled data from 48 genetic studies, which included nearly 17,000 people who had a stroke and nearly 600,000 people who did not have a stroke. The ages of all participants ranged from 18 to 59 years.
A genome-wide search has revealed two loci that are strongly associated with an earlier risk of stroke. One of them coincided with the spot where the blood type genes are located.
Then a second analysis of specific blood type genes found that people whose genomes encoded for a variety of group A had a 16% higher chance of having a stroke before age 60, compared to a group of other blood types.
For those with a group O1 gene, the risk was 12 percent lower.
The researchers note, however, that the additional risk of stroke in people with blood type A is small, so there is no need for further vigilance or screening in this group.
“We still don’t know why blood type A poses a greater risk,” Says Senior author and vascular neurologist Stephen Kettner of the University of Maryland.
“But it likely has something to do with blood clotting factors such as platelets and cells lining blood vessels as well as other circulating proteins, all of which play a role in the formation of blood clots.”
While the study results may sound alarming, this blood type may alter the risk of early stroke, let’s put these findings in context.
Each year in the United States, just under 800,000 people suffer a stroke. Most of these events - about Three out of four It occurs in people aged 65 and over, and the risk doubles every decade after age 55.
Also, the people in the study lived in North America, Europe, Japan, Pakistan, and Australia, and people of non-European ancestry made up only 35 percent of the participants. Future studies with a more diverse sample could help clarify the significance of the findings.
“It is clear that we need more follow-up studies to elucidate the mechanisms of increased stroke risk,” Kettner Says.
Another key finding of the study came from comparing people who had a stroke before the age of 60 with those who had a stroke after the age of 60.
For this purpose, the researchers used a data set of about 9,300 people over the age of 60 who had had a stroke, and about 25,000 people over the age of 60 who had not had a stroke.
They found that the increased risk of stroke in type A blood became non-significant in the late stroke group, suggesting that strokes that occur early in life may have a different mechanism compared to those that occur later.
Strokes in young adults are less likely to be caused by a build-up of fatty deposits in the arteries (a process called atherosclerosis), and more likely to be caused by factors related to clot formation, the authors say. Say.
The study also found that people with blood type B were nearly 11% more likely to have a stroke compared to people without stroke, regardless of their age.
Previous studies She suggests that the part of the genome that codes for blood type, called the “ABO locus,” is linked to coronary artery calcification, which limits blood flow, and heart attacks.
The genetic sequence of blood groups A and B has also been associated with a slightly increased risk of developing blood clots in the veins, called venous thrombosis.
This paper was published in Neurology.