People with type A blood appear to be more likely to have a stroke before the age of 60 than people with other blood types, according to a 2022 study.
blood types Describe the rich array of chemicals displayed on the surface of red blood cells. Among the most common are those named A and B, which can be present together as AB, individually as A or B, or not present at all, as O.
Even within these major blood groups, there are subtle differences that arise from mutations in the responsible genes.
Now, genomic research has revealed a clear link between the A1 subset gene and premature stroke.
The researchers pooled data from 48 genetic studies, which included nearly 17,000 people with stroke and nearly 600,000 people without stroke. All participants ranged from 18 to 59 years old.
A genome-wide search revealed two loci strongly associated with a prior risk of stroke. One of them coincided with the spot where the blood type genes were located.
A second analysis of specific blood group genes found that people whose genomes coded for the A variety had a 16% higher chance of having a stroke before the age of 60, compared to a group of other blood types.
For those with the group O1 gene, the risk was 12 percent lower.
The researchers note, however, that the additional risk of stroke in people with type A blood is small, so there is no need for additional vigilance or screening in this group.
“But it likely has something to do with blood clotting factors such as platelets and the cells that line blood vessels as well as other circulating proteins, all of which play a role in the formation of blood clots.”
Although the study results may seem alarming that this blood type may alter the risk of early stroke, let’s put these findings into context.
Each year in the United States, fewer than 800,000 people suffer a stroke. Most of these events – about Three out of four Occur in people aged 65 and over, and the risk doubles every decade after the age of 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 clarify the mechanisms of increased stroke risk,” Ketner said He said.
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, the researchers used a dataset of about 9,300 people over the age of 60 who 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 the Type A blood group became nonsignificant 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 the buildup 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 type B blood were approximately 11% more likely to have a stroke than people without stroke, regardless of their age.
Previous studies They suggest that the part of the genome that codes for blood type, called the “ABO locus,” is associated with coronary artery calcification, which limits blood flow, and heart attacks.
Genetic sequencing of blood types A and B has also been associated with a slightly increased risk of blood clots in the veins, which is called venous thrombosis.
This paper has been published in Neurology.
A version of this article was first published in September 2022.