We typically don’t think about our blood type and how it may affect our health. But a new study shows that knowing whether we’re blood type A, B, O, or AB could actually help us determine our risk of developing coronary heart disease.
Researchers examined participants in two large studies: the Nurses’ Health Study (NHS) and the Health Professionals’ Follow-Up Study (HPFS). Out of 121,700 female participants in the NHS, 62,073 women were included in this particular study. The HPFS enrolled 51,529 men, and 27,428 of them were included in this study.
The participants self-reported their blood type (A, B, O, AB, or unknown) and their Rh factor (positive, negative or unknown) in a questionnaire. The frequency for blood type was:
- Type O: 42.9 percent of women; 43 percent of men
- Type A: 36 percent of women; 37.2 percent of men
- Type B: 13.3 percent of women; 12.3 percent of men
- Type AB: 7.8 percent of women; 7.5 percent of men
During up to 26 years of follow up of the NHS participants, 2,055 cases of coronary heart disease were diagnosed. In the 20-year follow-up period in the HPFS, 2,015 cases of coronary heart disease were documented. The researchers also took into account other factors that could contribute to heart disease, including age, diet, smoking, alcohol use, physical activity and family history.
After analyzing the results of their data, they found that the increased risk of coronary heart disease for type A blood was 8 percent; for type B was 11 percent, and for type AB was 20 percent. Rh factor did not appear to have any effect on these results.
This is interesting news indeed, but what exactly is it about non-O blood types that increase the risk of heart disease? Well, there are a couple of theories.
Some evidence shows that plasma levels of factor VIII-vWf complex in individuals with non-O blood types were 25 percent higher than in those with O blood type. The vWf complex has an important role in the stoppage of blood flow and in the formation of blood clotting, as well as the development of atherosclerosis.
Other research shows that A, B, and AB blood groups — but especially the A blood type — also have higher levels of total cholesterol and LDL cholesterol.
If You’re Not an O Blood Type, Should You Worry?
In short, no. While A, B, and AB blood groups do appear to have a modestly higher risk of coronary heart disease, other lifestyle factors play a much bigger role in increasing your risk.
Like age and family history, your blood type is a risk factor you can’t control, so there really is no point in worrying too much about it. Instead, focus on risk factors that you can control, like your diet, physical activity, smoking, and overconsumption of alcohol. Also, regardless of your blood type, you can help prevent heart disease even further by taking heart-protective nutrients like CoQ10, magnesium and omega-3 fatty acids.
 He M et al. ABO blood group and risk of coronary heart disease in two prospective cohort studies. Arterioscler Thromb Vasc Biol. 2012;32:1-7.