Our blood types may not seem overly important in the scheme of things, unless we’re about to donate blood or receive donated blood, but they have been found to impact our health. Research has shown that people with certain blood types may be at a higher risk of conditions like heart disease, stroke, and some cancers. A new study suggests that breast cancer may be among them.

A meta-analysis on the potential link between blood type and breast cancer was recently published in the journal Oncotarget. The team drew data from 29 studies with more than 13,000 breast cancer patients. The goal was to see if there is compelling evidence for the link, as past research has suggested there is one.

According to the findings, blood type A was the most common type found in breast cancer patients, and it carried an 18% higher risk of breast cancer than type O. Meanwhile, B, AB, and Rh factor were not found to have a significant link compared to type A.

While more research is needed, the team says blood type may impact breast cancer due to blood group antigens, which are proteins found on the surface of cells, including in the breast. They may play a role in cancer development or spread due to their impacts on the immune system or cell behavior.

The researchers write, “While our findings suggest a statistical association between blood type A and breast cancer risk, they do not establish a direct causal relationship. Further research should explore ABO gene polymorphisms, antigen expression patterns, and immune-related pathways to better understand the underlying mechanisms. Incorporating genetic analysis may help clarify the biological relevance of ABO blood groups in breast cancer.”

You can read the whole study here.

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