Blood type linked to higher risk of early stroke



Dr. Braxton Mitchell

New research shows that individuals with blood type A have a 16% higher risk of early stroke (EOS) than those with other blood types.

On the contrary, the results of a meta-analysis of nearly 17,000 cases ischemic stroke In adults younger than 60, they have shown that having blood type O reduces the risk of EOS by 12%.

In addition, the associations with risk were significantly stronger in EOS than in those with late stroke (LOS), suggesting a stronger role for clotting factors in younger patients, the researchers note.

“What this tells us is that perhaps what puts you at risk for stroke as an adult is your blood type, which really gives you a much higher risk of thrombosis and stroke compared to late onset,” said co-author Braxton Mitchell, PhD, professor of medicine, epidemiology and public health at University of Maryland School of Medicine, Baltimore, said Medscape Medical News.

The results were Posted online August 31 in Neurology.

A strong bond

The Genome-wide Association Study (GWAS) was conducted as part of the Early Hereditary Ischemic Stroke Consortium, a collaboration of 48 different studies across North America, Europe, Japan, Pakistan and Australia. evaluated early onset of ischemic stroke in patients aged 18 to 59 years.

The researchers included data from 16,927 patients with stroke. Of these, 5,825 had a stroke before the age of 60, which is defined as early onset. GWAS results were also examined for approximately 600,000 individuals without stroke.

The results showed that two genetic variants associated with blood groups A and O appeared to be strongly associated with the risk of early stroke.

The researchers found that the protective effects of type O were significantly stronger with EOS versus LOS (odds ratio [OR]0.88 vs 0.96, respectively; s = .001). Similarly, the association between type A and increased EOS risk was significantly stronger than the association found in LOS (OR, 1.16 vs 1.05; s = .005).

Using polygenic risk scores, the researchers also found that the genetic risk is greater for varicose veins blood clotsanother thrombotic condition, was more associated with EOS than with LOS (s = .008).

Previous studies have shown a link between stroke risk and . variables ABO The gene that determines blood type. The new analysis indicates that type A and O genetic variants account for nearly all of those genetically associated with early stroke, the researchers noted.

While the findings point to blood type as a risk factor for stroke in young adults, Mitchell cautions that, “Currently, blood type has no implications for preventive care.”

“The risk of stroke due to blood type is lower than other risk factors that we know about, such as smoking and Hypertension“I would be more concerned about these other risk factors, especially because they may be modifiable,” he said.

He noted that the next step in the study is to assess how blood type interacts with other risk factors known to increase stroke risk.

“There may be a subset of people, if you have type A blood and you have some of these other risk factors, you’re likely to be at particularly high risk,” Mitchell said.

More research is needed on younger patients

in accompanying opening notes, Jennifer Jules Majersek, MD, assistant professor of neuroscience at the University of Utah, Salt Lake City, and Paul Lacaze, PhD, associate professor and chair of the Public Health Genomics Program at Monash University, Australia, note that the study fills a gap in stroke research, which It mostly focuses on the elderly.

“In approximately 40% of subjects with EOS, stroke is cryptic, and there is scant data from clinical trials to guide the choice of preventive strategies in this population, as subjects with EOS are often excluded from trials,” Majersek and Lakaz wrote. .

“This work has deepened our understanding of the pathophysiology of EOS,” they add.

The editors note that future research can build on the results of this analysis, “with the goal of a more rigorous understanding of the pathophysiology of stroke, leading to targeted preventive therapies for EOS and reduced disability in patients’ most productive years.”

Mitchell echoed the call for greater involvement of young stroke patients in clinical trials.

“As we learn, stroke in the elderly is different from stroke in young people,” he said. “There are many common risk factors but there are also a few different factors … so there really is a need to include young people.”

The study was funded by the National Institutes of Health and the Department of Veterans Affairs. Mitchell, Majersek and Lakazi have not reported any relevant financial relationships.

Neurology. Posted online August 31, 2022. SummaryAnd the editorial

Kelly Whitlock Burton is a reporter for Medscape Medical News covering psychiatry and neuroscience.

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