About 15 million people worldwide suffer a stroke every year, according to the World Health Organisation (WHO). Of these, 5 million die, while another 5 million are left permanently disabled. Stroke can be fatal, and other consequences of it are nothing short of devastating. But what if your risk of having a stroke, especially before the age of 60, could be predicted? No, this is no fake prediction. The risk of stroke is already written in your blood. A groundbreaking study suggests that certain blood types have a higher risk of suffering an early-onset stroke.According to a new meta-analysis led by University of Maryland School of Medicine (UMSOM) researchers, your blood type could predict your risk of having a stroke before age 60. This could lead to potential new ways to predict and prevent strokes in young adults. The findings are published in the journal Neurology. What is a stroke
A stroke can occur when blood flow to the brain is blocked or there is sudden bleeding in the brain. There are two types of strokes.
- Ischemic stroke
- Hemorrhagic stroke
A stroke that occurs when the blood flow to the brain is blocked is called an ischemic stroke. Hemorrhagic strokes, on the other hand, occur when a blood vessel ruptures and bleeds into the brain. Ischemic stroke is the most common type, accounting for approximately 87% of all strokes. Blood type and stroke risk
The new study found that a person’s blood type may be linked to their risk of having an early stroke. The meta-analysis included all available data from genetic studies focusing on ischemic strokes, occurring in younger adults under age 60.“The number of people with early strokes is rising. These people are more likely to die from a life-threatening event, and survivors potentially face decades with disability. Despite this, there is little research on the causes of early strokes,” study co-principal investigator Steven J. Kittner, MD, MPH, Professor of Neurology at UMSOM and a neurologist with the University of Maryland Medical Center, said in a statement. Kittner and his team performed a meta-analysis of 48 studies on genetics and ischemic stroke that included 17,000 stroke patients and nearly 600,000 healthy controls who had never experienced a stroke. The researchers investigated the genetic factors associated with early strokes and pinpointed variations that could explain higher risks in some individuals.They 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 stroke were also more likely to have blood type B compared to controls. 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.What are the experts saying
“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 D. Mitchell, PhD, MPH, Professor of Medicine at UMSOM, said. They also stressed 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 study.“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. We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk,” said Dr. Kittner. Previous studies have also suggested that an A blood type has a slightly higher risk of developing blood clots in the legs, known as deep vein thrombosis.
“This study raises an important question that requires a deeper investigation into how our genetically predetermined blood type may play a role in early stroke risk. It points to the urgent need to find new ways to prevent these potentially devastating events in younger adults,” the researchers added.
