Research from the University of Maryland (USA) has revealed that individuals with blood type A, or type B, are more likely to suffer a stroke before the age of 60 compared to those with other blood types. People with type B blood are 16 percent more likely to experience an early stroke than others.
Meanwhile, those with blood type O, or type A, have a 12 percent lower risk of an early stroke.
Each blood type is characterized by a rich variety of chemical substances present on the surface of our red blood cells. Within these groups, there are subtle differences arising from mutations in the responsible genes.
What Did the Researchers Discover?
In this new study, scientists analyzed data from 48 previous genetic studies, involving around 17,000 stroke patients and approximately 600,000 control participants without strokes. The participants ranged in age from 18 to 59, as reported by Science Alert.
A genome-wide search identified two locations closely associated with the risk of early stroke. One of these coincided with the area where blood group genes are located.
Analysis of specific blood group gene types showed that individuals whose genome encodes for the variation of blood type B had a 16 percent higher risk of stroke before the age of 60 compared to participants with other blood types. Conversely, those with the gene for blood type A had a 12 percent lower risk.
The researchers also found that individuals with blood type B (the third group) had an approximately 11 percent higher likelihood of stroke, regardless of age.
“We still don’t know why blood type A predicts the highest risk,” said lead author, vascular neurologist Stephen Kittner.
“But it’s likely related to factors involved in blood clotting, such as platelets and cells lining blood vessels, as well as proteins involved in thrombus formation,” the scientist suggested.
It’s worth noting that the study participants lived in North America, Europe, Japan, Pakistan, and Australia, with non-European individuals making up 35 percent of the participants. Therefore, the researchers believe that further studies with a more diverse sample are needed. Stephen Kittner believes these would help “clarify the mechanisms behind the increased risk of stroke.”
The results of the study were published in the journal Neurology.
For reference, 15 million people worldwide suffer a stroke each year. It ranks as the second leading cause of death after ischemic heart disease. The risk of stroke is associated with high blood pressure, smoking, blood clotting disorders, obesity, and lack of physical activity. Often, stroke is influenced by genetic inheritance. According to new statistics, 25 percent of stroke survivors are under the age of 45. It most commonly affects men over 55 and women over 65. Doctors are confident that a healthy lifestyle and preventive measures can help avoid stroke in 80 percent of cases.