For people with blood type B, a sweeping new analysis of global health research adds one more factor worth keeping on the radar: a modestly but meaningfully elevated risk of developing type 2 diabetes.
The finding comes from a 2024 umbrella review one of the most comprehensive types of scientific analyses available which examined more than 270 reported associations between blood type and various health outcomes. After applying a rigorous series of statistical tests designed to filter out weak or unreliable results, researchers found that only one association held up to the highest standard of evidence: the link between blood type B and type 2 diabetes.
What the research actually found
The review was led by epidemiologist Fang-Hua Liu of Shengjing Hospital of China Medical University, whose team systematically searched six major scientific databases, covering studies published from their inception through February 2024. Their analysis included 51 systematic reviews comprising a combined 270 health associations tied to ABO and Rhesus blood groups.
Each of those associations was put through a series of statistical stress tests. Researchers examined how strong and consistent the evidence was across different studies, whether the datasets were large enough to be considered trustworthy, and whether signs of bias such as small studies inflating effects were present. They also assessed whether each finding would likely hold up if tested again in future research.
Most of the 270 associations failed those checks. The one that did not was the connection between blood type B both positive and negative and a higher risk of developing type 2 diabetes compared to people with non-Blood type, That elevated risk was quantified at approximately 28%, on average.
How significant is a 28% increase
In isolation, a 28% increase sounds alarming, but context matters considerably. Researchers are careful to point out that this figure is modest compared to the diabetes risk tied to other well established factors.
Consuming just 50 grams of processed meat daily increases type 2 diabetes risk by around 37%. A consistently sedentary lifestyle can raise it by as much as 112%. And being overweight remains one of the most powerful risk factors known to science. Blood type, by contrast, is a fixed biological trait that sits lower on the risk hierarchy but it is not irrelevant.
Where the 28% figure becomes more meaningful is in combination with other risk factors. For someone with blood type B who also carries additional risks related to diet, physical activity, or body weight, the cumulative picture shifts enough to warrant closer attention and more proactive lifestyle management.
What blood type actually is and why it might matter
Human blood is classified into eight main groups based on the sugars and proteins present on the surface of red blood cells. Types A, B, and AB are named for the antigens sugar molecules that can trigger an immune response found on those cells. Type O blood carries neither A nor B antigens. The Rh factor, which gives blood its positive or negative designation, refers to a separate protein that determines blood compatibility.
Previous research has suggested that these subtle cellular differences may influence susceptibility to certain diseases. The biological mechanism behind the blood type B and diabetes association, however, remains unclear. The authors of the 2024 review did not investigate what might be driving the elevated risk. A separate 2025 study has proposed that the gut microbiome could be a contributing factor, but that line of inquiry is still in early stages and requires further investigation.
What this means for people with blood type B
The finding does not mean that having blood type B will lead to diabetes the vast majority of people with type B blood will never develop the condition. What the research does suggest is that the association is real and not an artifact of poorly designed studies, which is meaningful in a field where many reported blood-type-and-disease links do not survive rigorous scrutiny.
For people with blood type B, particularly those already managing other risk factors, the takeaway is practical: standard preventive steps around diet, regular physical activity, maintaining a healthy weight, and routine screening for blood sugar levels carry even more value than they might for the general population.
More broadly, the review highlights how much work remains to be done in understanding the relationship between blood type and disease, and underscores the importance of applying strict scientific standards before drawing firm conclusions from medical research.
