Stroke: people with this blood group more at risk? Our cardiologist answers

Smoking, high blood pressure, diabetes, cholesterol, being overweight Or lack of physical activity are proven and well-known risk factors for stroke (Stroke). But a meta-analysis published in the specialized journal Neurology and carried out by researchers from the University of Maryland Medicine in the United States highlighted a new parameter who could predict the risk of having an early stroke (before the age of 60 years): the blood group. The scientists analyzed 48 studies written on the subject, including 16,730 victims of ischemic stroke (or cerebral infarction, the most common stroke) as well as 600,000 control patients in good health who have never had a stroke. All were aged 18 to 59 years old. They then examined all chromosomes collected to identify genetic variants associated with stroke and discovered a link between the occurrence of an early stroke and the area of ​​the chromosome which includes the gene determining whether an individual’s blood type is A, AB, B or O.

Group O more sheltered?

After adjusting for gender and other factors (not cited), their results showed that:

► Peopleblood group A had a risk 16% higher of early stroke compared to other groups.

► People from blood group O had 12% less risk of early stroke compared to other groups.

► The link between blood group and the occurrence of a late stroke (after the age of 60) was much weaker than that found between blood group and early stroke.

For the moment, scientists have not determined of specific cause to these correlations. “This is probably due to factors of blood clottingas platelets and cells that line blood vessels, as well as other circulating proteins, all of which play a role in the development of blood clots“, explain the researchers in a publication accompanying the study. Indeed, an ischemic stroke occurs whena cerebral artery is blocked, often due to a blood clot. Obviously, additional follow-up studies are necessary to clarify these mechanisms.

“Scientific data still fragile”

So, what do we think of these results? “For now, this is preliminary data and today, we cannot consider that blood type is a predictive factor of stroke risk. As a result, we do not have a targeted strategy for patients who have this or that blood group. These are still fragile “scientific” data, especially since there are much simpler means of prevention (not smoking, controlling blood pressure, cholesterol, diabetes, fighting a sedentary lifestyle, etc.) than based on blood type. Let’s focus on the risk factors editable“, explains Professor Charlotte Cordonnier, Vice-President of the French Neuro-Vascular Society (SFNV) and head of the neurology and neurovascular pathology department at Lille University Hospital, specializing in the management of strokes. “People with blood type A should not worry of an early stroke or initiate further medical screening or testing based on these results“, would like to reassure the authors of the study.