Blood Type A Linked to Higher Risk of Early Stroke, Research Shows

A recent study has revealed a potential correlation between blood type and the risk of experiencing a stroke at a younger age. Researchers have discovered that individuals with blood type A may face a slightly elevated risk, while those with blood type O might have a reduced risk. Further investigation is necessary to fully understand the underlying mechanisms and to develop targeted prevention strategies.

About 15 million individuals globally experience a stroke annually, according to the World Health Organization (WHO). Of these, 5 million succumb to the condition, while another 5 million are left with permanent disabilities. Strokes can be fatal, and their consequences are often devastating. But could your risk of experiencing a stroke, especially before the age of 60, be predicted? The answer may lie within your blood.

A groundbreaking study suggests that specific blood types are associated with a higher risk of early-onset stroke. According to a new meta-analysis conducted by researchers at the University of Maryland School of Medicine (UMSOM), your blood type could potentially predict your likelihood of suffering a stroke before the age of 60. This could pave the way for innovative approaches to predict and prevent strokes in young adults. The findings have been published in the journal Neurology.

Understanding Stroke

A stroke occurs when blood flow to the brain is interrupted, either due to a blockage or sudden bleeding. There are two primary types of strokes:

• Ischemic stroke
• Hemorrhagic stroke

An ischemic stroke happens when a blood clot obstructs an artery, restricting blood flow to the brain. Hemorrhagic strokes, conversely, occur when a blood vessel ruptures and bleeds into the brain. Ischemic stroke is the more prevalent type, accounting for approximately 87% of all stroke cases.

Blood Type and Stroke Risk: What the Study Reveals

The recent study indicates a potential link between a person's blood type and their risk of experiencing an early stroke. The meta-analysis incorporated data from multiple genetic studies focusing on ischemic strokes in adults under the age of 60.

Steven J. Kittner, MD, MPH, Professor of Neurology at UMSOM and a neurologist at the University of Maryland Medical Center, stated that the incidence of early strokes is increasing. He emphasized that these individuals face a higher risk of mortality and potential long-term disability.

Kittner and his team analyzed 48 studies on genetics and ischemic stroke, involving 17,000 stroke patients and nearly 600,000 healthy individuals without a history of stroke. The researchers investigated the genetic factors associated with early strokes, identifying variations that could explain the increased risk in certain individuals.

The study revealed that individuals 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 those with late stroke and individuals who had never experienced a stroke. Both early and late stroke patients were also more likely to have blood type B compared to the control group. The study found that people with blood type A had a 16% higher risk of having an early stroke, compared to other blood types. Those who had blood type O had a 12% lower risk of having a stroke than people with other blood types.

Expert Perspectives on Blood Type

Braxton D. Mitchell, PhD, MPH, Professor of Medicine at UMSOM, explained that their meta-analysis examined genetic profiles and discovered associations between blood type and the risk of early-onset stroke. He noted that the association between blood type and later-onset stroke was considerably weaker compared to early stroke.

The experts also clarified that the increased risk is relatively small, and individuals with blood type A should not be overly concerned about experiencing an early-onset stroke or undergoing additional screening or medical tests based on this study.

Dr. Kittner added that the reasons behind the higher risk associated with blood type A remain unclear but likely involve blood-clotting factors, such as platelets and cells lining blood vessels, as well as other circulating proteins that contribute to blood clot formation. He emphasized the need for further research to elucidate the mechanisms underlying the increased stroke risk. Previous studies have also suggested a slightly higher risk of developing blood clots in the legs, known as deep vein thrombosis, in individuals with blood type A.

The researchers concluded that the study highlights the importance of further investigating how genetically determined blood type may influence early stroke risk. They emphasized the urgent need to discover new strategies to prevent these potentially devastating events in younger adults.