People with A and B blood group at higher risk of DVT and heart disease: AHA Study

Netherlands: Can having a particular blood type makes you more susceptible to diseases? A recent study seems to suggest so. According to the study, published in the AHA journal Arteriosclerosis, Thrombosis, and Vascular Biology, people with blood types A and B are at a higher risk of developing dangerous blood clots compared to people having type O blood. Also, people with A and B blood groups are at a higher risk of developing certain types of heart diseases.

The study found that compared to people with type O blood, those with types A or B had a combined 8% higher risk of heart attack and 10% increased risk of heart failure. Also, those with A and B blood groups were 51% more likely to develop deep vein thrombosis and 47% more likely to develop a pulmonary embolism. Deep vein thrombosis is a clot that usually occurs in the leg and when a clot travels to the lungs it is called pulmonary embolism.

Having type A or B blood did however lower the risk of high blood pressure by 3% compared to those with type O blood.

Previous studies have shown an association between heart disease and ABO gene that exists in people with A, B or AB blood types, but not in people with type O blood. Pim van der Harst, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands, and colleagues determined the spectrum of phenotypes linked to the ABO blood group system, using genetic determinants of the ABO blood group system.

The researches assessed the risk of 41 health and disease outcomes, and 36 linear traits associated with the ABO blood group system in the UK Biobank cohort. The study involved a total of 406 755 unrelated individuals. Blood groups A, B, and O were determined based on allele combinations of previously established single-nucleotide polymorphisms rs8176746, rs8176719 in the ABO gene. Blood group AB was excluded owing to its relatively small sample size.

Key findings of the study include:

"Determining someone's blood group is relatively easy, low in cost and widely used," she said. "General practitioners might use this information in the prevention and treatment of cardiovascular disease, and medical professionals can consider including blood group information in future trials for risk and treatment approaches." Nevertheless, Groot said the findings should not be evaluated on their own.

Dr Mary Cushman, who was not involved in the study, said people with blood types A and B need to be aware that surgery, trauma and immobilization increase the risk of blood clots. Everyone can lower their risk by maintaining a healthy weight and diet and exercising regularly, she said.

"At this point, we don't understand the reasons (behind the findings). However, we know that people who are not O blood type tend to have higher cardiovascular risk, so that maintenance of healthy lifestyle is the best approach," said Cushman, medical director of the Thrombosis and Hemostasis Program at the University of Vermont Medical Center in Burlington.

The study was limited because researchers excluded people with type AB blood due to their small number compared to other blood types. Cushman said the research also was hindered by a lack of cause-and-effect explanations – especially when it came to high blood pressure.

"Why non-O type blood would lower hypertension when it increases cardiovascular diseases is … not clear," she said.

"I don't advise that patients with non-O blood types get distressed over these findings, but that they simply utilize them to consider how they might take better care to prevent cardiovascular diseases," Cushman said. "Many of these diseases can be prevented through lifestyle and treatment of hypertension and high cholesterol."

The study, "Genetically Determined ABO Blood Group and its Associations With Health and Disease," is published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

DOI: https://doi.org/10.1161/ATVBAHA.119.313658