A 2022 study found that individuals with type A blood appear to be more likely than those with other blood types to get a stroke before the age of 60.
The wide range of substances that are visible on the surface of our red blood cells are described by blood types. The names A and B, which can be present together as AB, separately as A or B, or not at all as O, are among the most well-known.
Subtle differences caused by gene mutations can be seen even among these primary blood types.
Recent advances in genetic research have revealed a direct link between the A1 subgroup gene and early-onset stroke.
About 17,000 stroke victims and approximately 600,000 non-stroke controls were included in the 48 genetic studies that comprised the data the researchers collated. The age range of each participant was 18 to 59.
Two regions were highly linked to an early risk of stroke, according to a genome-wide investigation. One was in the region where the blood type genes are located.
When compared to a population of persons with different blood types, those whose genomes coded for a variation of the A group had a 16 percent higher risk of stroke before the age of 60, according to a second investigation of particular blood-type genes.
The risk was reduced by 11% in people who carried the group O1 gene.
The higher risk of stroke among those with type A blood, according to the researchers, is negligible, thus there is no need for further screening or monitoring in this population.
According to lead author and vascular neurologist Steven Kittner of the University of Maryland, “we still don’t know why blood type A would impart a greater risk.”
However, it most certainly has something to do with circulating proteins, platelets, and cells that coat blood arteries, all of which are involved in the formation of blood clots.
Let’s put the research findings—which suggest that a person’s blood type may affect their chance of developing a stroke in their early years—into perspective.
Just nearly 800,000 people have a stroke in the US every year. About three out of every four of these incidents involve adults 65 years of age or older, with chances rising every ten years following that.
Additionally, the study’s participants were from North America, Europe, Japan, Pakistan, and Australia, with just 35% of them having non-European ancestry. Future research with a more varied sample may be able to shed further light on the results’ importance.
According to Kittner, “We obviously need further follow-up research to elucidate the reasons of increased stroke risk.”
Comparing individuals who experienced a stroke before the age of 60 to those who experienced a stroke after the age of 60 led to another important study conclusion.
The researchers utilized a dataset of around 9,300 over-60s who had strokes and roughly 25,000 over-60s controls who didn’t have strokes for this.
They discovered that the type A blood group’s higher risk of stroke diminished in the late-onset stroke group, indicating that strokes that develop early in life could have a different mechanism from those that happen later.
The study also discovered that regardless of age, those with type B blood were around 11% more likely to get a stroke than non-stroke controls.
Previous research suggests that coronary artery calcification, which inhibits blood flow, and heart attacks are linked to the “ABO locus,” a region of the genome that codes for blood type.
The genetic makeup of blood types A and B has also been linked to a marginally increased risk of venous thrombosis, or blood clots in veins.
This article appeared in Neurology.
This story initially appeared in a form in September 2022.