Research shows that people with one of these blood types are more likely to have a stroke before age 60 than people with other blood types.
blood type Describe the wide variety of chemicals that appear on the surface of red blood cells.
The best known are those named A and B, which can exist together as AB, individually as A or B, or not at all as O.
Even within these major blood types, there are subtle differences that arise from the underlying genetic mutations.
In a study published in 2022, genomics researchers revealed a clear link between genes in the A1 subgroup and early-onset stroke.
The researchers compiled data from 48 genetic studies, including about 17,000 stroke patients and 600,000 non-stroke controls. All participants were between the ages of 18 and 59.
A genome-wide search revealed two locations strongly associated with early risk of stroke. One of them matched where the blood type gene was located.
Then, a second analysis of specific types of blood group genes found that people with genomes encoding group A variations were less likely to have a stroke before age 60 compared to other blood group populations. was found to be 16% higher.
For people with genes in the O1 group, the risk was 12% lower.
However, researchers note that the additional risk of stroke in people with blood type A is small, so there is no need for special vigilance or screening in this group.
“We still don’t know why people with blood type A are at higher risk.” said Stephen Kittner, senior author and vascular neurologist at the University of Maryland;
“But it’s more likely to have something to do with blood clotting factors such as platelets, the cells lining blood vessels, and other circulating proteins, all of which play a role in the development of blood clots.”
The findings that blood type can change early risk of stroke may seem alarming, but let’s put these results into context.
Just under 800,000 people in the United States experience a stroke each year. Most of these events are 3 out of 4 people – Occurs in people over age 65, with risk doubling every 10 years after age 55.
Participants in the study also lived in North America, Europe, Japan, Pakistan, and Australia, and only 35 percent of participants were of non-European descent. Future studies with more diverse samples may help clarify the significance of the results.
“It is clear that further follow-up studies are needed to elucidate the mechanisms underlying the increased risk of stroke,” Kitner said. said.
Another key finding of the study came from comparing people who had a stroke before age 60 with those who had a stroke after age 60.
To do this, the researchers used a dataset of about 9,300 people over the age of 60 who had had a stroke and about 25,000 controls over the age of 60 who had not had a stroke.
They found that the increased risk of stroke in blood type A was no longer significant in the late-onset stroke group, suggesting that strokes that occur early in life may have different mechanisms than strokes that occur later in life. It suggests that there is a gender.
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Strokes in young people are less likely to be caused by the buildup of fatty deposits in the arteries (a process called atherosclerosis) and more likely to be caused by factors involved in blood clot formation, the authors said. I am. said.
The study also found that people with blood type B were about 11 percent more likely to have a stroke than non-stroke controls, regardless of age.
Previous research The study suggests that the part of the genome that encodes blood types, called the ABO locus, is associated with coronary artery calcification, which restricts blood flow, and heart attacks.
Genetic sequences for blood types A and B are also associated with a slightly higher risk of blood clots in the veins, called venous thrombosis.
This paper is Neurology.
A previous version of this article was published in September 2022.
