Blood Type May Affect Heart Disease Risk

Studies have indicated that ABO blood group might influence plasma lipid level and recently, several genome-wide association studies found that variants at ABO locus were associated with plasma lipid levels and inflammatory markers that were associated with the CHD risk.
Scientists at the Harvard School of Public Health (Boston, MA, USA) examined data covering nearly 90,000 participants aged from 30 to 75 who were followed for 20 years or more in two large well-known American studies that included a cohort of 62,073 women and a cohort of 27,428 adults.

The proportions of men and women in the studies with various blood types were the same as in the general population, and the scientists 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.

The 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%. Those with blood type AB had a 23% increased risk for heart disease, those with type B had an 11% increased risk, and those with type A had a 5% increased risk, compared to people with type O.

The mechanisms that cause blood type to affect heart disease risk were not investigated, 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.

Lu Qi, MD, PhD, the senior author of the study, said, "It is important to know your blood type, just as it is good to know your cholesterol and blood pressure levels. If you know you are at higher risk, you can reduce the risk by adopting a healthier lifestyle, such as eating right, exercising, and not smoking." 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. The study was published on August 14, 2012, in the journal Arteriosclerosis, Thrombosis and Vascular Biology.

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Harvard School of Public Health