Depending on your blood type, you may be at higher risk of diabetes, research suggests.
According to a 2024 study, people with blood type B – positive or negative – are at slightly higher risk of developing type 2 diabetes than people with non-B blood type.
How much higher?
About 28 percent, on average. This may not seem like a lot, but it can be significant enough to tip the scales if other risk factors are involved.
“Many systematic reviews with meta-analyses have been published, exploring the correlations between ABO and Rh blood groups with various health outcomes,” wrote a team led by epidemiologist Fang-Hua Liu of Shengjing Hospital of China Medical University.
“However, to date, the association between these blood groups and human health outcomes remains controversial. The current general review included 51 systematic reviews with meta-analysis articles with 270 associations.
“We recalculated each association and found a single (instance of) convincing evidence of an association between blood group B and risk of type 2 diabetes mellitus compared to non-B blood group.”
Human blood is classified into eight main groups based on the sugars and proteins, or lack thereof, present on the surface of your red blood cells.
Types A, B and AB are based on the presence of antigens – sugar molecules that can trigger an immune response. Type O blood does not contain A or B antigens. Meanwhile, Rhesus (Rh) factors are proteins that determine blood compatibility and give your blood its positive or negative designation.
Previous studies have suggested that these subtle differences in our blood cells may be linked to increased vulnerability to certain diseases.
Liu and his colleagues undertook their study to systematically assess the links between blood type and disease across a catalog of approximately 270 different health outcomes.
A systematic review is a study that examines published articles on a given topic and analyzes their results collectively. A general review brings together systematic reviews – a kind of giant synthesis that offers a broader picture.
Think of individual studies as trees; a systematic review is like standing outside a grove, while an umbrella review is like flying a drone over an entire forest of groves.
“We systematically searched PubMed, Web of Science, Embase, Scopus, Cochrane Library and several regional databases from inception until February 16, 2024, to identify systematic reviews with meta-analyses of observational studies evaluating associations between ABO and Rh blood groups and various health outcomes,” the researchers explained.
To sort through the 270 reported links between blood type and disease, the researchers put each one through a series of statistical stress tests designed to weed out weak or unreliable results.
They looked at the strength of the evidence, whether the results were consistent across different studies, and whether the data sets were large enough to be trustworthy.
They also checked for signs of bias, such as small studies exaggerating effects or an unusually high number of positive results.
Importantly, they asked whether each association would likely hold up if tested again in future research. Most associations have not passed these checks.
Ultimately, only one link, between blood type B and type 2 diabetes, met the highest standards of evidence.
This suggests that the link is real, albeit relatively weak: only 28% above the current baseline. This is much lower than the risk associated with diet, weight or lifestyle.
For example, just 50 grams of processed meat per day increases the risk of type 2 diabetes by 37 percent. A sedentary lifestyle can increase the risk by 112 percent. And being overweight is one of the biggest known risk factors.
The researchers also did not examine what might cause this increased risk. A 2025 study suggests the gut microbiome may be involved; however, further research is needed.
The findings suggest that there is a real, tangible association between blood type and type 2 diabetes – one that people can factor into their perception of their own risk.
Still, your blood type alone won’t make or break your risk of diabetes. Diet, activity levels and weight matter much more – it’s just another piece of a puzzle that scientists are still putting together.
The research was published in BMC Medicine.
This article was fact-checked by Jess Cockerill and edited by Fiona MacDonald. Although we are proud of our process, we are only human. If you spot an error, please let us know.
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