According to a new research, blood type may be linked with the risk for occurrence of early-onset stroke (EOS) before the age of 60. People with type A blood exhibited 16% more risk for EOS when compared to other blood types. On the other hand, type O blood was shown to have a 12% lower risk of EOS in a meta-analysis of approximately 17,000 instances of ischemic stroke in people under 60 years of age. Additionally, the relationships with risk were considerably greater in patients with EOS compared to those with late-onset stroke (LOS), suggesting that prothrombotic variables have a stronger role in younger individuals.

The blood type increases the risk of clotting and stroke in young individuals compared to those who experience stroke later in life. A genome-wide association study (GWAS) was conducted to evaluate early onset ischemic stroke in participants 18 to 59 years of age. Overall, 16,927 stroke patients' data were included by the researchers and of these, 5825 people experienced an EOS before the age of 60. For about 600,000 individuals without stroke, their GWAS data were reviewed. Two genetic variants linked with blood types A and O were shown to be strongly linked to an increased risk of developing an early stroke.

Investigators discovered that protective effects of type O were considerably more potent with EOS versus LOS (odds ratio [OR], 0.88 vs 0.96, respectively). The correlation between type A and elevated EOS risk was also much greater than that observed in LOS (OR, 1.16 vs 1.05).  With the aid of polygenic risk scores, the researchers discovered that the stronger genetic risk for venous thromboembolism (another prothrombotic condition) was more significantly connected with EOS than with LOS.

Previous research has linked variations in the ABO gene, which defines blood type, to an increased risk of stroke. According to the novel analysis, almost all of the genetic variations associated with early stroke are of type A and O. However, blood group does not seem to have implications for preventative care, despite the fact that the data suggest that blood type is a risk factor for stroke in younger people. Blood type has a lower probability of causing a stroke than other modifiable risk factors such as high blood pressure and smoking. There might be a subset of individuals where, if they have blood type A and some of the other risk factors, it is likely that they might be at greater risk.

As persons with EOS are frequently excluded from studies, there are few data from clinical trials to help guide the selection of preventative interventions in this population. Nearly 40% of people with EOS get cryptogenic strokes. Using the findings from this analysis as a foundation, future research can aim to develop a more accurate knowledge of stroke pathophysiology, resulting in targeted preventative therapies for EOS and a decrease in disability during patients' peak productive years.

Stroke in older persons is not similar as stroke in younger persons. A wide array of shared, as well as distinct risk factors, exist. Thus, the inclusion of young individuals with stroke in clinical trials is required. Further studies should investigate how the type of blood interacts with other well-known risk factors to escalate stroke risk.