Maybe you’ve heard blood type matters for transfusions—but did you know it might also affect your risk of having a stroke before age 60? According to a 2022 meta-analysis, by University of Maryland School of Medicine (UMSOM) researchers, people with blood type A have a modestly higher risk of what experts call early-onset ischemic stroke. Here’s the lowdown — what the study found, what it doesn’t mean, and what you can do about it.
What the 2022 study discovered
Researchers pooled data from 48 genetic studies involving nearly 17,000 stroke patients (all under age 60) and almost 600,000 control participants who never had a stroke.
Here’s what the researchers found:
- People with blood type A had about a 16% higher risk of early-onset ischemic stroke compared to those with other blood types.
- On the flip side, those with blood type O had roughly a 12% lower risk of early stroke.
- The association was stronger in younger adults (under 60) than in people older than that.
- They also noted that the increased risk is “modest” — this isn’t something that guarantees anything, just something that adds into your overall risk profile.
Why does blood type A carry more risk?
The study didn’t definitively pin down why type A has this edge when it comes to stroke risk, but there are some good clues:Blood clotting factors: People with non-O blood types (especially A) tend to have higher levels of certain proteins, like von Willebrand factor (vWF) and Factor VIII, which help blood clot. Bigger clot risk = higher chance of ischemic stroke.Genetic link: The locus (area) of the chromosome that codes for the ABO blood group was implicated in the analysis. That means the genetic “region for blood type” showed up as relevant in the stroke risk search. But important: none of this proves causation. Having type A don’t cause stroke directly, it just appears associated. Lifestyle, environment, and other risk factors still play much larger roles.
What it doesn’t mean
Before you start panicking or making big health changes just because of your blood type, here are a few calming facts:The risk increase is relatively small. It’s not like having type A means you’ll definitely have a stroke. It’s just one factor among many.People with blood type A aren’t recommended to undergo special screening just because of their type. Doctors aren’t saying you need extra tests solely based on this finding. The strongest effects were in younger adults (<60). For older age groups, the blood type-stroke connection was weaker.
Who should pay extra attention
If you have blood type A, it’s good to be informed. But what really matters is combining that with other known risks. These situations may increase risk more:
- If you have high blood pressure (hypertension)
- If you smoke or have a history of smoking
- If you have high cholesterol or other cardiovascular risk factors (diabetes, obesity, sedentary lifestyle)
- If you have a family history of strokes or cardiovascular disease
What you can do to reduce your stroke risk
Blood type is something you’re born with; you can’t change that. But you can control a lot of other factors. Whether you’re type A or not, here are smart moves:
- Track your blood pressure regularly and keep it in a healthy range.
- Quit smoking if you do, or avoid starting.
- Eat a heart-healthy diet — lean proteins, plenty of vegetables, fruits, whole grains.
- Exercise regularly — even moderate activity helps protect against stroke.
- Manage medical conditions like diabetes, cholesterol, weight.
So, blood type A does seem to bump up the risk of early ischemic stroke by about 16% compared to other blood groups, and type O seems to have a modest protective effect. But by itself, your blood type isn’t something to worry about in isolation. What really counts are all the other risk factors, lifestyle, medical history, and habits, that you can change.If you’re curious, talk with your doctor about your individual risk, especially if you’re under 60, type A, and have other risks like high blood pressure or smoking.
