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Scientists claim people with this blood type more likely to have early stroke

Scientists claim people with this blood type more likely to have early stroke People with blood type A are more likely to suffer from a stroke before 60 (photo: Collage RBC-Ukraine)

Research shows that people with blood type A are more likely to suffer from a stroke before the age of 60 compared to people with other blood types, according to a study published in the journal Neurology.

Blood types describe a rich variety of chemicals present on the surface of red blood cells. Among the most well-known are those called A and B, which can be present together as AB, separately as A or B, or absent altogether as O.

Even within these major blood groups, there are small variations due to mutations in the responsible genes.

In the study, genomics scientists identified a clear link between the genome of the A1 subgroup and an early onset of stroke.

Researchers collected data from 48 genetic studies involving approximately 17,000 individuals with a stroke and nearly 600,000 individuals in a control group without a stroke. All participants were aged 18 to 59.

A whole-genome search revealed two locations closely associated with a higher risk of stroke. One of them coincided with the location of blood group genes.

A subsequent analysis of specific types of blood group genes found that people whose genome encoded the A group variation had a 16% higher risk of stroke before the age of 60 compared to the population of other blood groups. For those with the O1 blood group gene, the risk was 12% lower.

However, researchers noted that the additional risk of stroke in people with blood type A is small, so there is no need for special caution or screening in this group.

According to the words of the senior author of the article and vascular neurologist Steven Kittner from the University of Maryland, it is still not clear why blood type A increases the risk of early stroke.

Although the results of the study may seem alarming – blood type may alter the risk of early stroke – these findings should be placed in context.

Kittner pointed out that additional research to clarify the mechanisms of increased stroke risk was needed.

Another key conclusion of the study was made by comparing people who had a stroke before the age of 60 with those who had a stroke after 60.

To do this, researchers used a dataset of about 9,300 individuals aged 60 and over who had a stroke and about 25,000 control individuals aged 60 and over who did not have a stroke.

They found that the increased risk of stroke in the A blood group became insignificant in the late-onset stroke group, suggesting that strokes occurring at a young age may have a different mechanism compared to those occurring later.

According to the authors, strokes in young people are less likely to be caused by the accumulation of fat deposits in the arteries (a process called atherosclerosis) and more likely to be caused by factors related to thrombus formation.

The study also showed that people with blood group B are approximately 11% more likely to suffer a stroke compared to the control group without a stroke, regardless of their age.

Previous research indicates that a part of the genome that encodes blood type, called the ABO locus is associated with coronary artery calcification, limiting blood flow, and heart attack.

The genetic sequence of blood groups A and B is also associated with a slightly higher risk of thrombosis in veins, known as venous thrombosis.

For reference:

There are four main blood groups: O, A, B, and AB.

Blood group A - presence of A antigen on red blood cells and anti-B antibodies in plasma.

Blood group B - presence of B antigen on red blood cells and anti-A antibodies in plasma.

Blood group AB - presence of A and B antigens on red blood cells and absence of antibodies.

Blood group O - absence of A and B antigens on red blood cells and presence of anti-A and anti-B antibodies in plasma.

There are also two Rh factors: positive and negative. Thus, blood can be divided into 8 groups: A+, A-, B+, B-, AB+, AB-, O+, O-.

Blood groups are also denoted by Roman numerals:

O - I

A - II

B - III

AB - IV