If You Have This Blood Type, You're More at Risk of Blood Clots, New Study Says

Your blood type could increase your risk of experiencing certain blood clots, research shows.

There's been heightened attention on blood clots lately, due to the rare clotting complications linked to the Johnson & Johnson COVID vaccine. As a result, you may be wondering about your risk of experiencing a blood clot. While there are a lot of factors that play a part (including your age, the medications you take, whether you're pregnant, and even your height), another significant risk factor is your blood type. A new study just found that one blood type is more prone to developing certain kinds of blood clots than the others. Keep reading to find out what the researchers discovered, and to see which meds can put you at risk, If You Take This Medication, You're More Likely to Get a Blood Clot.

People with type A blood are more likely to experience certain blood clots, according to new research.

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A study out of Lund University in Sweden, published in the journal eLife on April 27, examined the health registries of more than five million people to find potential links between blood type and more than 1,000 diseases. The study found that people with type A blood are more likely to develop a blood clot, specifically pulmonary embolisms and portal vein thrombosis. As the Mayo Clinic explains, a pulmonary embolism is "a blockage in one of the pulmonary arteries in your lungs. In most cases, pulmonary embolism is caused by blood clots that travel to the lungs from deep veins in the legs or, rarely, from veins in other parts of the body (deep vein thrombosis)." Portal vein thrombosis is a blood clot in the portal vein, which carries blood from the intestines to the liver, according to Healthline.

An earlier study from the American Heart Association (AHA) journal Arteriosclerosis, Thrombosis, and Vascular Biology published in Jan. 2020 found that, compared to people with type O blood, those with type A and type B blood were 51 percent more likely to develop deep vein thrombosis and 47 percent more likely to develop a pulmonary embolism. However, the more recent Swedish study found that people with type A blood are specifically more at risk.

These kinds of blood clots, however, are distinct from those linked to the Johnson & Johnson vaccine, which are instances of thrombosis with thrombocytopenia syndrome (TTS). That occurs when a person has blood clots (thrombosis) along with low platelet counts (thrombocytopenia). "Platelets are the cells that circulate within our blood and bind together when they recognize damaged blood vessels," explains Marlene Williams, MD, director of the Coronary Care Unit at Johns Hopkins Bayview Medical Center. Many of the 15 instances of blood clots as a result of the Johnson & Johnson vaccine were specifically cases of cerebral venous sinus thrombosis (CVST), a rare and severe blood clot in the brain.

To learn about the latest vaccine-related blood clot case, find out why All Johnson & Johnson Blood Clot Patients Had This in Common, Until Now.

People with type O blood are more likely to have a bleeding disorder.

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While people with type O blood are less prone to blood clots, they are at a higher risk for another bleeding issue. The Swedish study found that people with type O blood are more likely to experience a bleeding disorder, specifically gastric ulcers and duodenal ulcers. Other bleeding disorders include hemophilia, Von Willebrand's disease, and Factor II, V, VII, X, or XII deficiencies, according to Healthline.

To see what else your blood type can tell you, If You Have This Blood Type, Your Dementia Risk Is High, Study Says.

People with any positive blood types or type O blood specifically are more likely to develop pregnancy-induced hypertension.

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According to the Cleveland Clinic, pregnancy-induced hypertension occurs in about 10 percent of pregnancies, and the Swedish study found a link between the condition and blood type. According to the research, those with type O blood or with RhD-positive blood (meaning any positive blood type) are more likely to experience pregnancy-induced hypertension. For more useful health news delivered straight to your inbox, sign up for our daily newsletter.

People with type B blood have a lower risk of kidney stones.

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Another finding in the Swedish study centered on blood type and kidney stones, a connection that hasn't been explored much before. The researchers found that people with type B blood are at a reduced risk of developing kidney stones.

"Our findings highlight new and interesting relationships between conditions such as kidney stones and pregnancy-induced hypertension and blood type or group," the study's senior author Gustaf Edgren, PhD, physician in the Department of Cardiology at Södersjukhuset Hospital, said in a statement. "They lay the groundwork for future studies to identify the mechanisms behind disease development, or for investigating new ways to identify and treat individuals with certain conditions." To see if your blood type may affect your heart health, know that If You Have This Blood Type, Your Heart Attack Risk Is Higher, Study Says.

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