Potentially good news for the 45% of Americans who have Type O blood: researchers said Tuesday that those people appear to have a slightly lower risk of developing heart diseasethan their neighbors with Type A, B or AB blood.
Dr. Lu Qi, an assistant professor of nutrition at the Harvard School of Public Health in Boston, analyzed heart disease risk in two large, multi-decade health studies — reviewing data collected from 62,073 women who participated in the Nurses’ Health Study, which was launched in 1976, and from 27,428 men who took part in the Health Professionals Follow-up Study, launched in 1986.
Adjusting for heart disease risk factors including diet, diabetes status, gender and race, Qi and his colleagues found that study participants with type AB blood had the largest heart disease risk — 20% greater than that of people with Type O blood. (The team calculated that the incidence of heart disease was 125 cases per 100,000 person-years.) Type B was next with an 11% greater risk, and type A was third with an 8% greater risk, the scientists reported.
The trend held up when the researchers compared their results with several other population studies recording the same factors. Across a total of seven studies, the increased risk for people with non-O blood types was 11% higher than that for people with Type O.