Researchers from the University of Maryland found that individuals with blood group type II may have a higher risk of stroke before age 60. The study, published in Neurology, showed that carriers of blood group A1 experienced early strokes 16% more often than other study participants.
Researchers analyzed data from 48 genetic studies involving about 17,000 patients who had suffered a stroke and nearly 600,000 people without the condition. All participants were aged between 18 and 59 years.
The authors examined the relationship between genetic variants of the ABO blood group system and the risk of early stroke. The analysis revealed that carriers of the A1 subgroup, corresponding to blood group type II, encountered strokes before age 60 more frequently. In contrast, individuals with blood group type I had a 12% lower risk than average.
"The number of early strokes is increasing. Such patients are more likely to die from this condition, and survivors may live with the consequences for decades. However, the causes of strokes at a young age are not well understood," noted one of the authors, vascular neurologist Stephen Kittner.
At the same time, the scientists emphasize that this refers to a small increase in risk. The authors do not believe that people with blood group type II need to undergo additional examinations or special screenings.
The reasons for the discovered link remain unclear. According to the researchers, it may be related to blood coagulation characteristics — for example, differences in the functioning of platelets, vascular wall cells, and proteins involved in thrombus formation.
The scientists also compared data from more than 9,000 people over 60 years old who had suffered a stroke with 25,000 participants from the control group. In this age category, the link between blood group type II and stroke disappeared. The authors suggest that early strokes may develop through different mechanisms than strokes in older age.
The researchers emphasize that the identified link does not mean that individuals with blood group type II are destined to have a stroke. It is merely a small increase in risk, the reasons for which still need to be studied. The researchers believe that blood coagulation and thrombus formation characteristics may play an important role; however, specialists do not currently recommend implementing additional screening solely based on blood type.
