• A new study links blood type to risk of stroke before 60.
  • The study found that people with blood type A are more likely to suffer a stroke before the age of 60 than those with blood type O.
  • This study could lead to potential new ways to prevent strokes in young adults.

Your blood type can tell you a lot more about your health than you might think. A new study published in the journal Neurology suggests that certain blood types are linked with a higher or lower risk of stroke before age 60. The researchers from the University of Maryland said in a press release that this ground-breaking research could lead to potential new ways to prevent strokes in young adults.

Researchers conducted the study by performing a meta-analysis of 48 studies on genetics and ischemic stroke that included 17,000 stroke patients and nearly 600,000 people who had never experienced a stroke, per the press release. Researchers then looked at all collected genetic data from the participants to identify genetic variations associated with a stroke and found a link between early-onset stroke (occurring before age 60) and the gene that determines whether a blood type is A, AB, B, or O.

The study found that people with early stroke were more likely to have blood type A and less likely to have blood type O (the most common blood type) compared to people with late stroke and people who never had a stroke. Both early and late strokes were also more likely to have blood type B.

After researchers adjusted for sex, they found those who had blood type A had a 16% higher risk of having an early stroke than people with other blood types. Those who had blood type O had a 12% lower risk of having a stroke than people 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,” said study co-principal investigator Braxton D. Mitchell, P.h.D., M.P.H., professor of medicine at UMSOM in a press release.

According to the release from the University of Maryland, the team of researchers emphasized that the increased risk was very modest and that those with type A blood should not worry about having an early-onset stroke or engage in extra screening or medical testing based on this finding. But, it’s simply another reason to remain vigilant about your health.

“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,” said study co-principal investigator Steven J. Kittner, M.D., M.P.H., Professor of Neurology at UMSOM in the press release.

This study had its own set of limitations, most importantly a lack of diversity among participants. “We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk,” said Dr. Kittner in the release.

“Stroke is the fifth leading cause of death and the leading cause of disability in the United States, but is the second leading cause of death in the world,” says Sandra Narayanan, M.D., board-certified vascular neurologist and neuro-interventional surgeon at Pacific Stroke & Neurovascular Center at Pacific Neuroscience Institute in Santa Monica. She adds that more than 50% of stroke survivors older than 65 have reduced mobility, which can lead to lower quality of life.

How can you prevent a stroke?

Fortunately, there are many strategies to prevent a first-time cerebrovascular event or to reduce the risk of recurrent stroke or TIA (transient ischaemic attack or “mini-stroke”). According to Dr. Narayanan, up to 80% of strokes can be prevented with these lifestyle changes:

  • Quit smoking.
  • Keep a blood pressure (BP) machine at home if you have high blood pressure and take measurements daily. Write these down and bring the log to your doctor’s appointments. Goal BP is <140/90 mm Hg (or <130/80 mm Hg for patients with diabetes mellitus).
  • Eat a Mediterranean-style diet rich in fruits, vegetables, whole grains, fish, and nuts.
  • Exercise—in any form, even if it’s just 10 minutes a day at first.
  • Know your cholesterol. If you’ve already had a stroke or TIA, aim for low-density lipoprotein (LDL) of <70 mg/dL. Knowing your numbers and partnering with the appropriate healthcare providers (PCP, neurologist, cardiologist) for routine follow-up, medication adjustment, and lab work is critical.
  • Consistency is key to maintaining healthy lifestyle interventions. Start early. 10-15% of strokes occur in adults <50 years of age.

The bottom line

This study adds to our knowledge of genetic and other unchangeable risk factors for diseases relating to the brain and blood vessels, says Dr. Narayanan. “As indicated above, healthy lifestyle interventions can accomplish much to prevent cerebrovascular disease from occurring or progressing. Being identified as having a riskier genetic profile for stroke may potentially serve as a positive impetus for lifestyle change, as well as initiate the conversation regarding medications or other strategies to reduce arterial or venous thrombosis.”

In agreement with the team of researchers on this study, Dr. Narayanan says further studies with more diverse populations are needed to clarify these findings and the mechanisms for differential stroke risks among certain blood types. But, this is a start!

From: Prevention US
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Madeleine Haase

Madeleine, Prevention’s assistant editor, has a history with health writing from her experience as an editorial assistant at WebMD, and from her personal research at university. She graduated from the University of Michigan with a degree in biopsychology, cognition, and neuroscience—and she helps strategize for success across Prevention’s social media platforms.