The influence of blood type on risk of early stroke (3 photos)

Researchers at the University of Maryland (UMD) have found that people with blood type A are at higher risk of early ischemic stroke, which occurs when blood flow to the brain is blocked. People with blood type O are at lower risk.





“Stroke is getting younger,” says Dr. Stephen J. Kittner, one of the study’s lead researchers and a neurologist at the University of Maryland (UMD) Medical Center. Mortality rates are rising, and those lucky enough to survive are often left disabled. Despite this, the causes of early strokes are largely unknown.

In 2022, Kittner and his colleagues conducted an analysis that looked at data from 48 genetic studies. The studies included more than 17,000 stroke patients and 600,000 healthy people who had never had a stroke. All participants were between the ages of 18 and 59.

By examining their genetic profiles, the researchers found a potential link between early strokes and a part of the chromosome that contains the gene that determines blood type.



"The association between blood type and late stroke was much weaker than it was for early stroke," said Dr. Braxton D. Mitchell, lead researcher and professor of medicine at the University of Maryland (UMD).

After adjusting for gender and other factors, the researchers found that people with type O blood, the most common blood type, had a 12 percent lower risk of stroke than other blood types. People with type A blood had a 16 percent higher risk of early stroke.

"We still don't know why blood type A is associated with an increased risk, but it appears that clotting factors, such as platelets and cells that line blood vessels, and other circulating proteins that form clots, play a role," Kittner explained.

Blood clots are a major cause of ischemic strokes because they block blood flow to the brain. Previous research has shown that people with blood type A may be more prone to blood clots in the legs, known as deep vein thrombosis.



"We definitely need more research to better understand why there is an increased risk of stroke," Kittner added.

Major risk factors for stroke include high blood pressure, high cholesterol, diabetes, smoking, and drinking alcohol. Obesity, poor diet, and lack of exercise can also significantly increase your chances.