Individuals with blood type A are 16 per cent more likely to have a stroke before the age of 60 compared to those in other blood groups, a new study has identified.

Scientists from the University of Maryland School of Medicine found that certain blood groups can trigger an ischemic stroke in middle-aged adults.

First author Dr Steven J. Kittner said: “The number of people with early strokes is rising. These people are more likely to die from the life-threatening event, and survivors potentially face decades with disability. Despite this, there is little research on the causes of early strokes.”

During the study, the team of academics analysed the genetics of approximately 600,000 healthy adults and 17,000 participants recovering from a stroke.

They found that adults with blood type A are 16 per cent more likely to have an early stroke compared to those with other blood types.

In addition, they discovered that people with blood type B were also at risk of early and late stroke compared to those with blood type O.

Fellow researcher Dr Braxton D. Mitchell said: “Our meta-analysis looked at people’s genetic profiles and found associations between blood type and risk of early-onset stroke.

“The association of blood type with later-onset stroke was much weaker than what we found with early stroke.”

Prior studies have reported that adults with blood type A are also more likely to suffer with deep vein thrombosis.

According to the academics, people with type A blood do not need additional screening or medical testing based on this finding.

Dr Kittner said: “We still don’t know why blood type A would confer a higher risk, but it likely has something to do with blood-clotting factors like platelets and cells that line the blood vessels as well as other circulating proteins, all of which play a role in the development of blood clots. We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk.”

Dr Mark T. Gladwin added: “This study raises an important question that requires a deeper investigation into how our genetically predetermined blood type may play a role in early stroke risk.

“It points to the urgent need to find new ways to prevent these potentially devastating events in younger adults.”

The study has been published in Neurology.

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