Blood Type May Affect Risk Of Heart Disease
August 15, 2012

Certain Blood Types Can Raise Risk Of Heart Disease

Connie K. Ho for — Your Universe Online

Researchers recently discovered that people who have blood type A, B, or AB could be at higher risk for developing coronary heart disease as compared to people who have blood type O.

The study´s findings are published in Arteriosclerosis, Thrombosis and Vascular Biology, a journal under the American Heart Association. The scientists determined that people with rare blood type AB, the blood type seen in only seven percent of the U.S. population, had the most increased risk for heart disease at 23 percent. People with type B blood had 11 percent increase risk, while people with type A blood had five percent increased risk. 43 percent of the U.S. population has type O blood.

"While people cannot change their blood type, our findings may help physicians better understand who is at risk for developing heart disease," explained lead author Dr. Lu Qi, an assistant professor in the Department of Nutrition at the Harvard School of Public Health, in a prepared statement.

One important finding of the study is that individuals need to know their blood type to avoid heart disease and to stay healthy.

"It's good to know your blood type the same way you should know your cholesterol or blood pressure numbers," commented Qi in the statement. "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."

In the project, the researchers analyzed data from two large, well-known U.S. studies. One study, the Nurses´ Health Study, included 62,073 women and the other study, the Health Professionals Follow-Up Study, included 27,428 adults. The individual age range spanned from 30 to 75, with participants in both groups followed for 20 years or more.

As well, the scientists considered the participants´ age, body mass index, diet, gender, race, menopause status, medical history, and smoking status. On the other hand, they did not examine the biological processes related to blood type and heart disease risk. There is evidence to suggest that type A blood is related to higher levels of low-density lipoprotein cholesterol, a waxy substance that can build up in the arteries. There is also data to show that type AB blood is connected to inflammation, which could impact the functioning capability of blood vessels.  Lastly, there is prior knowledge to show that clotting could be higher in people with type O blood due to a substance that assists in blood flow.

"Blood type is very complicated, so there could be multiple mechanisms at play," noted Qi in the statement.

Factors that could have impacted the study include environmental issues and other ethnic groups.

“Most of things that are this modest, most of the time they don´t meaningfully change how you´d think about your risk overall,” Dr. Amit Khera, director of the Preventive Cardiology Program at the University of Texas Southwestern Medical Center, told the Washington Post. “This shouldn´t cause much alarm for most of the population.”

Medical experts believe that the study´s findings need to be confirmed.

“I actually don´t know the blood types of any of my patients, and I would imagine that most cardiologists will tell you the same thing,” preventive cardiologist Dr. Richard A. Stein, director of the exercise and nutrition program at New York University´s Center for the Prevention of Cardiovascular Disease, mentioned in a WebMD article. “Maybe this will prove to be useful in our assessments of how aggressively to treat patients, but we aren´t there yet.”

Researchers hope to conduct further analysis on the topic.

"It would be interesting to study whether people with different blood types respond differently to lifestyle intervention, such as diet," Qi concluded in the statement.