People from groups A, B, and AB are more at risk than those with the more common blood type O, research shows.
Individuals with the rarest blood group, AB — found in about 7% of the population — were far and away the most vulnerable.
Compared with people having blood group O, their chances of suffering heart disease were raised by 23%.
Group B blood increased the risk by 11%, and type A by 5%.
“While people cannot change their blood type, our findings may help physicians better understand who is at risk for developing heart disease,” said lead researcher Professor Lu Qi, from the Harvard School of Public Health in Boston.
“It’s good to know your blood type the same way you should know your cholesterol or blood pressure numbers. If you know you’re at higher risk, you can reduce the risk by adopting a healthier lifestyle, such as eating right, exercising, and not smoking.”
The study’s findings, published in the American Heart Association journal Arteriosclerosis, Thrombosis and Vascular Biology, are based on an analysis of two large US health and lifestyle studies.
One, the Nurses’ Health Study, recruited more than 62,000 female health staff.
The other, the Health Professionals’ Follow Up study, involved about 27,400 male health workers.
Participants were aged between 30 and 75, and both groups were monitored for 20 years or more. The epidemiological study compared blood groups and heart disease incidence but did not probe the complex biological mechanisms behind the results.
However, there is evidence that type-A blood is associated with higher levels of the “bad” type of cholesterol, low-density lipoprotein.
This type of cholesterol combined with other substances can clog up arteries.
AB blood is linked to inflammation, which also plays an important role in artery damage.
People with type-O blood may benefit from a substance that is thought to assist blood flow and reduce clotting.
The researchers pointed out that the study group was mostly white Caucasian. It was not clear whether the same findings applied to other ethnic groups.
Prof Qi said: “It would be interesting to study whether people with different blood types respond differently to lifestyle intervention, such as diet.”