People with blood type B face a 28 percent higher risk of developing type 2 diabetes compared to individuals with non-B blood types, according to a 2024 review published in BMC Medicine.
Blood Type B and Type 2 Diabetes Risk Compared to Lifestyle Factors
Human blood falls into eight main groups based on surface sugars and proteins. Types A, B, and AB feature antigens that trigger immune responses, while type O lacks these antigens. Rhesus (Rh) factors determine positive or negative designations. While past studies linked these blood cell variations to disease vulnerabilities, epidemiologist Fang-Hua Liu and a team at Shengjing Hospital of China Medical University set out to test the strength of those links across 270 different health outcomes.
The research team evaluated 51 systematic reviews with meta-analyses, encompassing 270 associations between blood groups and health conditions. After running statistical stress tests to check for consistency, dataset size, and bias, only one association met the highest standard of evidence: the link between blood group B and type 2 diabetes mellitus.
The 28 percent increase in risk for blood type B individuals is relatively small when stacked against other established lifestyle factors. For instance, consuming just 50 grams of processed meat daily raises type 2 diabetes risk by 37 percent. A sedentary lifestyle increases that risk by 112 percent, while being overweight remains one of the strongest known risk factors.
Statistical Stress Tests Weed Out 269 Weak Health Links
The umbrella review methodology allowed researchers to survey a vast forest of scientific literature rather than single studies. Liu and colleagues searched PubMed, Web of Science, Embase, Scopus, the Cochrane Library, and regional databases from inception until February 16, 2024. They weeded out findings where small studies exaggerated effects or showed an unusual concentration of positive results.
Most of the 270 investigated associations failed these rigorous statistical checks. The researchers noted that while numerous systematic reviews previously explored correlations between ABO and Rhesus blood groups and health outcomes, the associations largely remained controversial until subjected to this systematic filtering.
Biological Drivers Behind the Blood Group B Association Remain Unknown
The published research did not examine the underlying biological mechanisms driving the increased risk for blood type B carriers. Although a 2025 study suggests the gut microbiome may play a role, the Shengjing Hospital research team emphasized that further investigation is necessary to confirm any causal pathways.
Blood type alone does not determine diabetes outcomes. Diet, body weight, and physical activity levels exert a far greater influence on an individual’s overall metabolic health, serving as major factors in type 2 diabetes prevention.
Common Questions About Blood Type and Diabetes Risk
Does having blood type O protect against type 2 diabetes?
The 2024 umbrella review found convincing evidence only for an association involving blood type B compared to non-B groups.
How much does blood type B increase your chances of diabetes?
Carrying blood type B, whether positive or negative, increases the risk of type 2 diabetes by about 28 percent on average compared to non-B blood types. This risk increase is notably smaller than the 112 percent increase associated with a sedentary lifestyle or the risks tied to being overweight.
What databases did researchers search for the 2024 review?
Liu and colleagues searched PubMed, Web of Science, Embase, Scopus, the Cochrane Library, and several regional databases from inception until February 16, 2024, identifying 51 systematic reviews with meta-analyses for their umbrella review.