Blood Group May Affect Heart Attack Risk

Healthcare professionals should consider a person's blood group when assessing their cardiovascular risk as people with A, B, and AB blood types may be at greater risk of cardiovascular events, particularly heart attacks, than individuals with O blood types.

There are some risk factors for heart attack that can be addressed, such as a poor diet, lack of exercise, and smoking. However, some heart attack risk factors cannot be changed, such as age, gender, and a family history of heart disease. A new study suggests that blood type should be added to the list.

Scientists at the University Medical Centre Groningen conducted a meta-analysis of studies that reported participants' blood types and the incidence of cardiovascular events, including heart attack, heart disease, heart failure, and cardiovascular death. The data included more than 1.3 million adults who were a part of 11 cohorts across nine studies. The investigators used the data to assess how each blood group might impact the risk of coronary events, combined cardiovascular events, and fatal coronary events.

The team identified 771,113 individuals with a non-O blood group and 519,743 individuals with an O blood group in the analysis of all coronary events. Among people with a non-O blood group, 1.5% (11,437) experienced a coronary event, compared with 1.4% (7,220) of people with an O blood group. In the analysis of combined cardiovascular events, they identified 708,276 people with a non-O blood group and 476,868 people with an O blood group. Among individuals with a non-O blood group, 2.5% (17,449) experienced a cardiovascular event, compared with 2.3% (10,916) who had an O blood group.

The scientists noted the that individuals with non-O blood types have higher concentrations of a blood-clotting protein called von Willebrand factor, which previous studies have linked to thrombotic events. Additionally, they point out that people with non-O blood groups, especially those with an A blood type, tend to have higher cholesterol levels, which is a known risk factor for poor cardiovascular health. The odd ratio (OR) for combined cardiovascular events was significantly higher in non-O blood group carriers, at 1.09 (95% CI 1.06-1.11).

Tessa Kole, a Master's degree student and lead author of the study said, “We demonstrate that having a non-O blood group is associated with a 9% increased risk of coronary events and a 9% increased risk of cardiovascular events, especially myocardial infarction. In future, blood group should be considered in risk assessment for cardiovascular prevention, together with cholesterol, age, sex, and systolic blood pressure.” The study was presented at the annual meeting of the European Society of Cardiology, held April 29 to May 2, 2017, in Paris, France.