A scientific review conducted in 2024 established a link between having blood type B and an increased risk of developing type 2 diabetes. This conclusion was reached through a detailed analysis of various studies comparing blood groups with overall health.
The findings indicated that individuals with blood type B, whether positive or negative, have, on average, a 28% higher risk than individuals with other blood types of contracting the disease. However, the researchers emphasize that this correlation does not determine the origin of diabetes nor allow for predicting who will be affected.
The research team, led by epidemiologist Fang-Hua Liu, affiliated with Shengjing Hospital of China Medical University, examined 51 scientific reviews. These reviews, collectively, investigated 270 potential connections between blood types and health problems.
The analysis process involved compiling data from previous research to identify patterns that might not be visible in an isolated study. The scientists also verified the consistency of the findings, the sufficiency of participants in the studies, and the possibility of biases or distortions in the results. Furthermore, they assessed whether such associations could disappear in future investigations.
The vast majority of the relationships examined did not show sufficient robust evidence to be considered reliable. The only association that passed all the most rigorous criteria was that between blood type B and type 2 diabetes, when compared to other blood groups.
The researchers warned that, so far, the link between these blood groups and human health outcomes remains a controversial topic. This result is significant because it limits the conclusion to a relationship supported by more consistent evidence, but this does not imply that blood type B is the cause of diabetes.
Blood is categorized into eight primary groups, defined by the combination of the ABO system with the Rh factor. The distinction between types A, B, AB, and O is made by the presence or absence of certain antigens—molecules capable of provoking an immune reaction. The Rh factor, in turn, specifies whether the blood is positive or negative.
Although previous studies have sought to establish whether these biological differences could be linked to susceptibility to diseases, the exact mechanisms justifying the association between type B and diabetes have not yet been defined. A subsequent study, dated 2025, suggested the hypothesis that the gut microbiome, composed of intestinal microorganisms, could be involved in this relationship, although this possibility still requires confirmation.
It is important to note that the 28% increase in risk linked to blood type B is smaller than the risk associated with certain habits and health conditions. For example, consuming 50 grams of processed meat daily is linked to a 37% higher risk of developing type 2 diabetes. Additionally, sedentary lifestyle can raise this risk by 112%, and excess weight is also among the main factors favoring the onset of the disease.
These percentages should not be interpreted as individual predictions nor as directly comparable measures in all circumstances. The risk of developing diabetes is multifactorial, and the association with blood group should not replace the evaluation of other health conditions.
The study, published in the journal BMC Medicine, contributes to the advancement of knowledge about possible links between blood characteristics and pathologies. Additional research is essential to elucidate why type B relates to type 2 diabetes and what the real importance of this connection is in clinical practice.