Your blood type may affect your risk of having a stroke before age 60, study finds

euronews.com:

People with type A blood may be at higher risk of having a stroke before the age of 60 compared to other blood groups, researchers have found.

In contrast, those with blood type O are less likely to have an early-onset stroke, according to the new meta-analysis.

The research was carried out by a team led by scientists from the University of Maryland School of Medicine in the United States, who looked at the relationship between genetic characteristics such as blood type and their relationship to stroke.

To do so, they looked at data from 48 genetic studies on ischemic strokes in adults between the ages of 18 and 59. Ischemic strokes are caused by a blockage of blood flow to the brain.

In total, the studies included around 17,000 stroke patients and nearly 600,000 healthy controls who had never experienced a stroke.

“We were interested in trying to identify the genetic determinants of stroke,” the study’s co-principal investigator Braxton Mitchell told Euronews Next.

“For stroke, we've known for a long time that there's a big environmental component, but there's also a genetic component,” said Mitchell, who is a professor of medicine at the University of Maryland School of Medicine.

To examine this further, he and his colleagues looked across people’s genetic profiles, and ended up finding a link between early-onset stroke and the area of the chromosome that includes the gene determining a person’s blood type.

Humans have four main blood groups, A, B, AB and O, and a person’s blood group is determined by the genes they inherit from their parents. Blood group O is the most common.

What the researchers found was that those who had early-onset stroke were more likely to have blood type A and less likely to have blood type O, compared