Estrogen and Heart Disease

Could the same hormone that helps reduce the risk of heart disease in some cases raise it in others? MIT researchers are shedding light on this apparent contradiction. They are helping explain why estrogen seems to protect certain people from cardiovascular disease while being strongly associated with heart attack in others.

Research scientist Amanda Shearman and her team at MIT's Center for Cancer Research examined a genetic variation in certain cells that interact with estrogen. Their results show that this variation indicates a high risk of heart attack. Shearman's team identified the variation by surveying the blood samples and medical histories of 1,739 people. The subjects were second-generation participants in the Framingham Heart Study-a landmark initiative that tracked the medical health of 5,209 Framingham, MA, residents and their descendants for 50 years.

Subjects two and three have a genetic variation that makes them more likely to have heart attacks. (Courtesy of Amanda Shearman)

The researchers found that 12 percent of the men with the genetic variation had suffered heart attacks over a 27-year period. In contrast, only 5 percent of men without the variation suffered heart attacks. Further studies on women need to be conducted, Shearman says, "because there were too few cardiovascular events among them for such a result to have had any meaning."

The scientists hope that discovering the variation will allow doctors to genetically identify people who might be at risk for cardiovascular disease. But diagnosing the variant during a doctor's visit is a ways off. "The results in our...paper are statistically significant and quite exciting but do not yet provide a basis for a diagnostic test," says Shearman.