By David W Freeman
(CBS/AP) A new study suggests that the risk for stroke is tied to blood type, with men and women with type AB and women with type B facing greater risk than people with type O.
The research doesn’t prove the link. But it fits with other studies that have tied A, B, and AB to heart attack and to blood clots in the legs. And type O has been linked to a heightened risk for bleeding, which implies less chance of the clots that are responsible for most strokes.
“There’s increasing evidence that blood type might influence risk of chronic disease,” said one of the study leaders, Dr. JoAnn Manson, chief of preventive medicine at Harvard’s Brigham and Women’s Hospital. “It’s not at the level where we want to alarm people and we want to make that clear. But it’s one more element of risk that people would want to know about,” and it could encourage them to keep watch on their keep blood pressure and cholesterol, she said.
The study was led by Brigham’s Dr. Lu Qi and was presented Wednesday at a meeting of the American Heart Association. It involved 90,000 men and women in two observational studies that have gone on for more than two decades.
Looking at the 2,901 strokes that have occurred during that time and taking high blood pressure and other stroke risk factors into account, researchers found that men and women with AB had a 26 percent higher risk of stroke compared to those with type O and that women with type B blood had a 15 percent greater risk compared to women with type O.
What explains the link between blood type and stroke?