If You Have This Blood Type, You Could Be At Greater Risk For Stomach Cancer
It's thought that at least a third of Americans don't know their blood type, with many of us likely thinking it's only really important for blood donations. But which group our blood belongs to can actually tell us a lot about our immunity to certain diseases and even predict which conditions we might suffer from at some stage in our lives. As such, blood type is one of those genetic characteristics that's much more important than we might realize.
There are four main blood groups — A, B, AB and O — and which group our blood falls into is determined by which antigens are present on the surface of our red blood cells. All cells in our body have these surface markers and the surface markers on our red blood cells are known as antigens — essentially any substance to which the immune system can respond. If you introduce an antigen into your body that isn't already on your red blood cells, the immune system attacks, which is why it's crucial to ensure the right blood type for blood transfusions.
These antigens can also tell us more about our body and its susceptibility to certain medical situations. For example, if you have a certain blood type you could be at risk of a painful death. Another recent study, meanwhile, suggests that those with type A or AB blood are at a higher risk of developing stomach cancer
You might be at a higher risk of stomach cancer if you have type A or AB blood
A 2019 study published in the journal BMC Cancer looked at the association of ABO blood groups with gastric cancer risk, noting how previous explorations of this link had yielded inconsistent results. In order to get more definitive answers, the researchers identified the blood type of 4,932 people with gastric cancer, alongside 6,158 control patients. They then evaluated the association of blood type with the risk of gastric cancer while carrying out a wide-ranging review of the literature and a meta-analysis of all relevant studies.
The results showed an association between those with type A blood and the risk of developing gastric cancer, and suggested type AB blood was also associated with gastric cancer risks. Specifically, the study showed that those with type A blood had a 13% higher risk of developing stomach cancer compared to those with type O. Meanwhile, type AB blood was associated with an 18% higher risk. The researchers' meta-analysis of other studies related to the subject also backed up these results, revealing similar patterns showing that those with blood type A were at a 19% greater risk of developing stomach cancer and those with blood type AB were at a 9% greater risk.
The authors also acknowledged earlier research that showed those with blood type A are more susceptible to the bacteria known as Helicobacter pylori, which is actually the leading cause of stomach cancer. This study, however, showed that those with blood type A were more at risk of developing stomach cancer regardless of whether they had an H. pylori infection or not, while those with blood type AB were more likely to develop the disease if they did have an H. pylori infection.
Don't panic if you have blood type A or AB
If you have blood type A, you don't need to be worried that you'll develop cancer simply as a result of that blood type. To be clear, the 2019 study simply suggests that those with type A and AB blood are at higher risk of developing the disease. It's also important to note that while genetic characteristics such as blood type can play a role in the risk of developing stomach cancer, so too can things like age, sex, ethnicity, and lifestyle. As noted by the 2019 study authors, for example, smoking, drinking, and eating large amounts of salted foods can also contribute Even climate change can have an effect on our health.
As noted by the researchers in the 2019 study, at the time, gastric cancer was the fifth most common cancer and the third leading cause of cancer death worldwide. In 2025, The American Cancer Society estimates that 30,300 new cases of stomach cancer will be diagnosed in the United States and that there will be around 10,780 deaths from this type of cancer. Thankfully, as a 2024 study published in BMC Public Health notes, rates of stomach cancer and death linked to the disease have shown a decreasing trend in the past decade, even while some countries show an increasing trend. But there's still the issue of population growth potentially leading to an increase in stomach cancer deaths overall. As such, understanding everything we can about the disease is crucial, and the 2019 study was a big step in that regard.