By Shyla Cadogan

More adults are surprisingly suffering strokes at younger ages, and scientists have turned their attention more toward this population to find out what’s causing this and why. Now, University of Maryland School of Medicine (UMSOM) researchers are suggesting that blood type may hold the answer to predicting if someone will suffer a stroke at an earlier age.

According to their findings, individuals under 60 with blood type A may be most at risk.

“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,” says study co-principal investigator Steven J. Kittner, MD, MPH, Professor of Neurology at UMSOM and a neurologist at the University of Maryland Medical Center, in a media release.

Kittner and team conducted a meta-analysis of 48 different studies on genetics and ischemic stroke. In total, the study included 17,000 stroke patients and 600,000 healthy controls. Following this, they looked across all collected chromosomes to find any genetic variants associated with stroke, ultimately finding a connection between early-onset stroke prior to turning 60 and the area of the chromosome that contains the gene which determines blood type.

Their findings report that those suffering an early stroke were more likely to have blood type A and less likely to have blood type O, which is the most common type. Those who had strokes later in life or people who never experienced a stroke did not show these results.

A notable similarity, however, is that early and late stroke sufferers were more likely to have B blood compared to healthy controls. Overall, after taking confounding factors out of the equation, the team found those with blood type A had a 16-percent higher risk of having an early stroke than those with other types. Those who had blood type O had a 12-percent lower risk of having early stroke.

“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,” explains Dr. Kittner.

Since the exact reasoning and mechanism for these results remains unknown, Kittner and the team don’t see an end to this research any time soon, and hope that more studies continue to explore this with greater patient diversity.

“We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk,” the researcher concludes.