Blood Types That Could Increase Your Risk Of Pancreatic Cancer

Pancreatic cancer is a relatively rare form of cancer when it comes to cases diagnosed per year. However, it remains a deadly type of cancer that accounts for a high percentage of annual deaths when compared to diagnosis rates.

In other words, you want to avoid pancreatic cancer if you can. And whether or not you're likely to be diagnosed with pancreatic cancer depends on a number of factors. Some are in your control. The American Cancer Society notes that tobacco users are at a higher risk, so if you never smoke or quit using tobacco, you may lower your risk. That said, other factors are hereditary, such as being born a biological male or having a history of pancreatitis. And there's another potential risk factor you can't change: your blood type.

You may already know your blood type, which is likely to be A, AB, B, or O. (Additional blood types do exist, but they make up a short list of the rarest blood types.) Among those four, three have been tentatively connected with pancreatic cancer: A, AB, and B.

A 2023 study in Cancer Epidemiology, Biomarkers and Prevention found that individuals who had a non-O blood type seemed to be more likely to be diagnosed with pancreatic cancer. The study also noted that while the evidence suggested that those with A blood types had a higher risk than those with B blood types, it was unclear which non-O blood type carried the highest risk for the disease.

These were not the first findings to identify a potential bridge between blood type and pancreatic cancer, though. A 2009 study in the Journal of the National Cancer Institute came to the same conclusion. After tracking the health data of 107,503 individuals over many years, researchers observed a higher incidence of annual pancreatic cancer diagnoses among people with non-O blood types. (In the study, B blood types showed the highest rates of diagnosis, followed by AB and then A.)

The lead author of the 2009 study, Dr. Brian Wolpin, cautioned against assuming that blood type alone could raise the risk of pancreatic cancer and suggested that perhaps blood type might be connected to the disease in other ways (via Dana-Farber Cancer Institute). Regardless, he shared a positive outlook, stating, "The association between blood type and pancreatic cancer risk provides a new avenue for getting at the disease's underlying biological mechanisms."

A theory posits that people with non-O blood types may be more prone to being infected by the bacteria Helicobacter pylori (H. pylori). (Here are other surprising ways your blood type can affect your health). A 2010 study in the Journal of the National Cancer Institute showed a probable (though not proven) link between H. pylori, pancreatic cancer, and A, B, and AB blood types.

What is it about H. pylori that makes it a possible precursor to pancreatic cancer? Once in the stomach, H. pylori can cause inflammation as it breaks down the protective tissues that line the gut. According to the American Cancer Society, H. pylori can fuel stomach ulcers, therefore potentially raising a person's pancreatic cancer risk. (Learn about the warning signs of an ulcer you should never ignore.)

While H. pylori may not necessarily lead to pancreatic cancer, it may put an individual at risk of other cancers. As the National Cancer Institute notes, H. pylori has been connected with stomach cancer, a form of non-Hodgkin lymphoma, and potentially colorectal cancer.