People With This Blood Type May Have Higher Risk Of Early Stroke: Study

People's blood types may be a factor in their risk for early stroke, a new study has found.

For their work, published Wednesday in the journal Neurology, a team of researchers looked at people's genetic profiles and their possible contribution to the risk of early-onset stroke (EOS). This is the stroke that occurs before a person hits 60 years old.

To do this, the researchers analyzed 48 different studies that looked at EOS in people aged 18 to 59. In total, there were 16,730 EOS cases and nearly 600,000 non-stroke controls who never had a stroke, the University of Maryland School of Medicine (UMSOM) noted in a news release.

Indeed, the researchers found "significant associations" between EOS and the part of the chromosome with the gene that determines blood type.

Specifically, they found that those who had EOS were "more likely to have blood type A and less likely to have blood type O" compared to those who had either a late onset stroke or who never had a stroke at all, UMSOM noted. Overall, those with blood type A had a 16% higher risk of EOS, while those with blood type O had 12% lower risks of stroke compared to those with other blood types.

"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," study co-principal investigator Braxton Mitchell of UMSOM said in the news release.

This doesn't mean that those with blood type A should be concerned as the increase was said to be "very modest," the researchers said. However, this warrants further study as certain blood types appear to be carrying a higher risk for 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," study co-principal investigator Steven Kittner of UMSOM said in the news release. "We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk."

For now, people can reduce their stroke risks by working on the factors that, unlike blood type, they can actually control. They include building better habits such as exercising, reducing salt intake, incorporating more fruits and vegetables in the diet and quitting smoking. It would also be wise to drink alcohol moderately. As Harvard Health Publishing noted, "there is no such thing as a small stroke."