It’s common knowledge that heart disease risk can be raised by smoking, obesity and your family history. Now, a new study adds to the list that your very own blood type might increase risk for future heart problems.
However, the researchers said following a healthy lifestyle can still make a difference to protect people with the higher risk blood types.
The senior author of the study is Lu Qi, an assistant professor in the Department of Nutrition at the Harvard School of Public Health in Boston.
Qi and colleagues reviewed two studies that tracked nearly 90,000 people for more than 20 years and found that coronary heart disease risk varied with participants’ blood types. People with type O blood had the lowest incidence of coronary heart disease, and compared with them, those with type AB blood were 23 percent more likely to have heart disease, while those with type B blood were 11 percent more likely, and people with type A were 5 percent more likely.
Blood type AB is the rarest blood type, it occurs in around 7% of Americans, while type O, the most common, occurs in around 43%.
The proportions of men and women in the studies with various blood types were the same as in the general population, and the researchers were able to control for a number of factors that can affect health and heart disease risk, such as age, gender, race, body mass index, diet, smoking, menopause and medical history.
However, the participants were mostly Caucasian, so it’s not clear whether the results would be the same for other ethnic groups. Environment also affects risk, says Qi.
Possible Reasons Not Explored
The researchers did not look into the mechanisms that cause blood type to affect heart disease risk, but evidence from other studies gives some clues.
Blood type A is linked to higher levels of low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol that clogs up arteries.
Blood type AB is linked to inflammation, which can affect how blood vessels work.
And people with blood type O have higher levels of a compound that has a beneficial effect on blood flow and clotting.
Although people can’t change their blood type, there are things they can do to reduce risk for heart disease.
Qi says it’s important to know your blood type, just as it’s good to know your cholesterol and blood pressure levels.
“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,” he explains.
Also, armed with findings like these, health care providers can tailor treatments more effectively. For instance,patients with blood type A could be advised to reduce cholesterol in their diet to lower their risk of heart disease, says Qi, who suggests further studies should now be done to look at the effect of diet and lifestyle changes on heart disease risk in people with different blood types.