A recent study from the University of Maryland School of Medicine found that individuals with blood type A have a higher risk of having a stroke before the age of 60. The ABO blood type system, which includes A, B, AB, and O blood types, was used for this analysis. 

The study analyzed 48 different genetic studies on ischemic stroke, including over 167,000 stroke patients and more than 599,000 healthy individuals.

The researchers found that individuals with blood type A accounted for 48% of early-onset strokes, the highest percentage among the affected population, while individuals with type O blood had the lowest percentage.

After adjusting for other factors, individuals with blood type A had a 16% higher risk of early-onset stroke compared to those with other blood types, while individuals with type O blood had a 12% lower risk.