A+, A-, B+, B-, AB+, AB-, O+, O-.  We all know these are the blood types everyone has, but is it possible your blood type can secretly affect your heart health? And how many of us know our blood type? A 2019 survey by Quest Diagnostics, a clinical laboratory company, found that 43% of Americans don’t know their blood types.

How can I find out my blood type?

Let’s start with how to learn your blood type. Unfortunately, the typical blood workup run by your PCP annually doesn’t usually include a test to determine your blood type, as it’s not considered a necessary part of routine exams or wellness checks. Additionally, insurance providers may not cover it unless there’s a medical reason for the test. However, there are a couple of ways you can learn this information. First, if you’ve had a surgical procedure or given birth, your blood type is likely on record and available upon request. If that doesn’t apply, donating blood is another relatively easy way to determine your blood type.  Not only do you find out a key piece of information about your body, but you can also help others by contributing to the short blood supply. 

In the United States, O+ is the most common blood type, found in about 37% of the population, followed by A+ in around 36% of people, according to the Stanford School of Medicine Blood Center. AB- is the rarest, occurring in less than 1% of Americans. The Red Cross considers people with Type O- blood the “universal blood donor” because it can be used in emergency blood transfusions for any other blood type.  Your blood type is determined by genetics and generally does not change during your lifetime.  However, in some cases, the blood types can change due to unusual circumstances, such as having a bone marrow transplant or getting certain cancers or infections. Not all of the changes in blood type are permanent.

How can blood type affect the health of your heart?

Scientists have been trying to better understand the relationship between disease and blood type since the early 1900s. When they first discovered antibodies and antigens on blood cells and plasma were inherited, the question about blood type and disease arose. The risk of heart disease came to the forefront in the late 1960s. It became clearer in the 1970s after the publication of the results from the Framingham Heart Study, which was the first large-scale study to identify common factors or characteristics that contribute to cardiovascular disease.

Since that early heart health study, a finding that continues to surface in various studies is people with type O blood could have a slightly different risk profile than people with type A & B blood types when it comes to certain health conditions. People with a non-O blood type (A, B, and AB) are at a higher risk of developing cardiovascular diseases, heart attacks, or experiencing heart failure. While the increased risk is small (types A or B had a combined 8% higher risk of heart attack and 10% increased risk of heart failure), the difference in blood clotting rates is much higher. People with type A and B blood were 51% more likely to develop deep vein thrombosis, clots usually occurring in the leg, and 47% more likely to develop a pulmonary embolism. This severe blood clotting disorder can also increase the risk of heart failure.

This increased risk might have to do with inflammation in the bodies of people with type A, type B, or type AB blood. The proteins in type A and type B blood may cause more "blockage" or "thickening" in the veins and arteries, increasing the risk of clotting and heart disease. 

While the research shows that blood type can tip the scale regarding someone's risk of developing heart disease, big factors such as diet, exercise, or even the level of pollution you're exposed to in your community are the major players in determining heart disease health. 

Should I change my lifestyle based on my blood type? 

There isn’t enough information to move this variable to the list of risk factors that physicians discuss with their patients, like age, cholesterol, nicotine habits, or blood pressure. While there is an effect of blood type on certain health variables, it is probably small and not nearly as consequential as having other more impactful health conditions such as diabetes. 

A person can’t change their blood type, but they can change behaviors like quitting smoking or exercising to reduce their risk for heart disease, which is where we should all be focused; variables that are under our control. 

More to come on how blood type affects your health, so stay tuned.

Research on whether your blood type affects your chances of disease is ongoing. Studies are investigating how blood types affect:

• Gastrointestinal microbiome (and related to this, your healthiest food choices).

• Blood clotting.

• Coronary heart disease.

• Developing certain types of cancer, such as stomach (gastric) and pancreatic cancer.