An intriguing link between people with non-O blood groups and a higher risk of adverse cardiac events is the subject of a new study from the European Society of Cardiology. Non-O blood groups, I.E. A, B, or AB blood groups have been associated with risk of heart problems in the past, but the newest study provides clearer evidence.
Past research suggesting this phenomenon came from case-control studies with not a lot of evidence, but the the present study included a meta-analysis of multiple prospective studies comparing O and non-O blood groups looking for any difference in risk for cardiovascular events: myocardial infarction AKA heart attack, coronary artery disease, ischaemic heart disease, heart failure and cardiovascular mortality.
Of nearly one-and-a-half million study subjects, an analysis of coronary and combined cardiovascular events included around 7-800,000 with a non-O blood group and 500,000 with an O blood group. Odds ratios for both analyses showed carriers of a non-O blood group to be at a higher risk of heart disease.
"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," explained lead author Tessa Kole.
Nine percent may not seem like a lot, studies like Kole’s at the very least shine a light on this connection for future study. In the mean time, researchers have a few guesses as to what factors could be influencing the increased risk of cardiac events for non-O blood groups.
Greater concentrations of von Willebrand factor, a blood clotting protein associated with thrombotic events
Galectin-3, a biomarker linked to inflammation and poor health outcomes for heart failure patients and which is also especially high in non-O blood group
More research is necessary to understand the connection completely, but for now, Kole recommends that “blood group should be considered in risk assessment for cardiovascular prevention, together with cholesterol, age, sex and systolic blood pressure. We need further studies to validate if the excess cardiovascular risk in non-O blood group carriers may be amenable to treatment."