Pm Images/Getty Images

Genetic traits—from eye color to hair retention—are shaped by our DNA. Blood type, determined by genetics, is more than a transfusion label; it offers insights into immune function and disease susceptibility.

Recent research indicates that individuals with non‑O blood types face a higher likelihood of heart attacks. Conversely, type‑O carriers may have an increased risk of fatal bleeding events. Although these findings can be unsettling, they underscore the value of personalized prevention strategies. Additionally, type‑A or AB blood has been linked to a greater incidence of gastric cancer. Overall, blood type carries more clinical significance than many realize.

Not every person with a particular blood type will experience these outcomes; the data reflect statistical risk rather than destiny. However, awareness can guide proactive health decisions.

Non‑O type blood is associated with a greater risk of cardiovascular events

Anusorn Nakdee/Getty Images

New evidence demonstrates that non‑O blood types are associated with a higher incidence of cardiovascular events—stroke, heart failure, and myocardial infarction—compared to type‑O individuals. The study reports a 9% greater risk of coronary events and overall cardiovascular complications, particularly heart attacks. Importantly, there was no significant difference in fatal coronary outcomes between the two groups, indicating that type‑O carries its own unique risks.

The findings were published in the Cardiovascular Journal of Africa and presented at Heart Failure 2017 and the 4th World Congress on Acute Heart Failure. This comprehensive meta‑analysis, directed by Tessa Kole of the University Medical Centre Groningen, aggregated data from nine prospective studies, encompassing 1,362,569 participants. Across these cohorts, 23,154 cardiovascular events were documented, allowing researchers to examine links between blood type and specific coronary outcomes, including combined cardiovascular incidents and fatal events.

There are several possible reasons why those with non‑O type blood are more at risk

Ktsdesign/sciencephotolibrary/Getty Images

Although the study did not pinpoint the exact mechanism, clinicians suspect that elevated levels of von Willebrand factor—a key clotting protein—may contribute to the increased cardiovascular risk observed in non‑O blood types.

A 2025 study in the Journal of the American College of Cardiology reported that non‑O blood types carried a heightened risk of cardiovascular events among hospitalized COVID‑19 patients. Similarly, a 2023 investigation in the Journal of Stroke and Cerebrovascular Diseases linked non‑O blood types to higher rates of stroke, myocardial infarction, and peripheral vascular disease, attributing these associations to von Willebrand factor and factor VIII—a second clotting protein.

These findings underscore the relevance of blood type in cardiovascular risk assessment, yet they do not imply inevitability. Lifestyle factors—diet, exercise, smoking cessation—remain pivotal and can substantially modify risk across all blood groups.