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If You Have This Blood Type, You May Be at Risk for Disease

Scientists have made a provocative finding about your innate chance of certain disorders.
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People with specific blood types may have a higher risk for certain diseases, a new study has found.

Analyzing health data from more than 5 million people in Sweden, researchers at the Karolinska Institute in Stockholm investigated the link between blood type, RhD status and more than 1,000 diseases. They identified 49 diseases linked to blood types, and one associated with having RhD-positive blood.

A person who is RhD positive has a protein called the D antigen on their red blood cells, while being RhD negative means the protein is missing.

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Risk of blood disorders ranges

The study, published in the journal eLife, reinforced some previous findings: People with type A blood are more likely to have blood clots, while those with type O blood are more likely to have a bleeding disorder, specifically gastric ulcers and duodenal ulcers, and women with type O blood are more likely to develop pregnancy-induced high blood pressure (hypertension).

Bleeding disorders include hemophilia and Factor II, V, VII, X, or XII deficiencies, which affect the blood's ability to clot. Hypertension happens during about 10 percent of pregnancies; it can impair the placenta's ability to deliver oxygen and nutrients to the fetus, the Cleveland Clinic says.

The researchers also discovered new links—having type B blood seems to carry a lower risk of kidney stones, and women who are RhD positive seem more likely to develop pregnancy-induced hypertension.

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More study needed, researchers say

"There is still very little information available about whether people with RhD-positive or RhD-negative blood groups may be at risk of certain diseases, or how many more diseases may be affected by blood type or group," said Torsten Dahlén, the study's lead author.

The researchers said more study is needed to confirm the results and determine whether blood types are in fact associated with a higher risk of certain health conditions, or if some other factor is responsible.

"Our findings highlight new and interesting relationships between conditions such as kidney stones and pregnancy-induced hypertension and blood type or group," said study senior author Gustaf Edgren, associate professor of epidemiology at the Karolinska Institute. 

"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," he said.

The link between blood types and disease has been in the news recently because of a potential COVID-19 connection. A large study published in April in The Annals of Internal Medicine found that people with type O or RhD-negative blood may have a 12% lower risk of testing positive for COVID and a 13% lower risk of developing severe COVID-19 or dying from the disease. Those who are RhD negative also seem to have some immunity against the virus.

To get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.

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