Knowing your blood type might reveal more than just your compatibility for transfusions—it could also provide clues about your long-term health risks, including certain cancers. A 2015 study found that individuals with Type O blood tend to have a lower risk of developing cancers such as stomach, pancreatic, and colorectal cancer. On the other hand, those with A, B, or AB blood types showed a higher likelihood of some cancers, especially stomach and pancreatic types.

In addition to cancer risk, Type O blood has been associated with a reduced risk of heart disease, possibly due to having fewer blood clotting factors. However, experts emphasize that blood type does not influence cancer survival rates. Most people only discover their blood type during medical treatments, and each type (A, B, AB, or O) can be either positive or negative depending on the presence of the Rh protein. While blood type may play a role in risk assessment, it is only one of many factors to consider for cancer prevention and overall health.