Discovering you have a higher risk of developing a long-term health condition usually comes down to checking your diet, family history, or how often you lace up your trainers.
However, researchers have found a different factor hidden away in your DNA that could play a massive role in how your body processes sugar. It turns out that your specific blood group does a lot more than just dictate who you can receive a transfusion from; it might actually influence your metabolic health.
While most people never give their blood type a second thought outside of a hospital visit, the statistical link between certain antigens and insulin resistance is shedding new light on how type 2 diabetes develops.
Researchers wanted to know how blood type impacts overall health.
A team of researchers set out to look at the relationship between blood type and a wide range of health outcomes, working through around 270 different reported links that had been identified across previous studies. Rather than conducting new experiments, they gathered and analysed the existing body of research, looking for associations strong enough to hold up under serious scrutiny.
This kind of review, which compiles and re-examines the results of many studies at once, is considered one of the most reliable ways to check whether a finding is genuinely solid rather than a fluke produced by a single piece of research. The team applied a series of statistical checks to each of the 270 reported links to see which ones held up and which ones fell apart.
Which blood type is involved?
After working through all 270 associations, only one survived the full set of tests with strong enough evidence to be considered convincing. People with blood type B, whether positive or negative, appear to have around a 28% higher risk of developing type 2 diabetes compared to people with any other blood type.
This is the only blood type link that made it through the researchers’ rigorous checks, which means it’s the only one they’re confident enough to highlight as likely being real rather than a statistical coincidence. Every other reported connection between blood type and disease either failed the tests or didn’t have enough evidence behind it.
What are blood types?
Blood is sorted into eight main groups based on tiny molecules found on the surface of red blood cells. Types A, B, and AB are named after specific molecules called antigens that sit on those cells, while type O has none of these antigens at all. The positive or negative part of a blood type refers to a separate protein that determines how compatible blood is for transfusions.
These differences between blood types might seem minor, but previous research has suggested that they can affect how vulnerable people are to certain diseases. The differences are subtle, but blood cells are involved in a huge range of bodily processes, which is why researchers think blood type could plausibly influence health in ways beyond just transfusion compatibility.
How significant is a 28% higher risk?
A 28% increase in risk sounds alarming, but it’s worth putting in context. Scientists describe it as a relatively small effect compared to the better-known risk factors for type 2 diabetes, the kind that come from lifestyle and weight rather than biology.
Eating 50 grams of processed meat every day increases diabetes risk by 37%, more than the blood type effect. A sedentary lifestyle raises the risk by 112%, and being considerably overweight remains one of the strongest known risk factors of all. Blood type B raises risk, but it’s nowhere near the top of the list of things that determine whether someone develops the condition.
It’s still noteworthy, despite being a small effect.
The reason scientists think this finding is worth knowing about, even though the risk increase is modest, is that risk factors tend to stack on top of each other. Someone who already has several other risk factors for type 2 diabetes might find that a 28% extra nudge from blood type is enough to tip the balance in a way it wouldn’t for someone with no other risks.
Knowing about this connection also gives people with blood type B an additional reason to pay attention to the lifestyle factors they do have control over, like diet, exercise, and weight, since those levers remain far more powerful than blood type in determining overall diabetes risk.
Scientists don’t yet know why this link exists.
The research confirmed that the link appears real but didn’t investigate what’s actually driving it at a biological level. That part of the puzzle is still unclear, and understanding the mechanism would require further dedicated research.
One line of thinking, suggested by a separate 2025 study, points to the gut microbiome as a possible explanation, with differences in gut bacteria potentially connecting blood type to diabetes risk. This remains speculative for now and would need proper investigation before any firm conclusions could be drawn.
For most people with type B blood, this doesn’t change much.
Having blood type B doesn’t mean diabetes is inevitable or even likely. It means there’s a slightly elevated risk that’s worth factoring into how you think about your health, particularly if other risk factors are also present.
The practical takeaway is straightforward: the lifestyle factors that protect against type 2 diabetes, staying active, maintaining a healthy weight, eating well, and not smoking, matter for everyone, but perhaps carry a little extra weight for those with blood type B. The things within your control remain far more influential than anything your blood type does in the background.
