Blood group helps determine a person’s risk of heart disease, a study has found.
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%.
The 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 workers. The other, the Health Professionals’ Follow Up Study, involved around 27,400 male health professionals.
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 (LDL).