Gene tests fail to predict women's heart risks

Gene tests that combined over 100 genetic mutations proved ineffective at predicting a woman's risk of a heart attack or stroke, U.S. researchers said on Tuesday.

They said high cholesterol, high blood pressure and a family history of heart disease were the strongest predictors of a woman's heart disease risk.

Many variations of genes have been identified that are associated with a higher risk of heart disease, but combining them into a risk prediction score did not help researchers find which women in a study of 19,000 participants would eventually develop the disease.

They found that after adjusting for traditional heart risk factors, a genetic risk score that combined 101 so-called single nucleotide polymorphisms or SNPs - a single-letter change in the genetic code - was not useful in predicting heart disease risk.

For years, teams have been using a tool called a genome-wide association study, in which researchers compare the genomes of people with a disease to those of healthy people, to look for common genetic differences that could help predict disease.

"While multiple genetic markers associated with cardiovascular disease have been identified by genome-wide association studies, their aggregate effect on risk beyond traditional factors is uncertain, particularly among women," Nina Paynter of Brigham and Women's Hospital in Boston, and colleagues wrote in the Journal of the American Medical Association.

The team developed two genetic risk scores based on genetic markers known to be associated with either heart disease or factors that cause heart disease, such as high cholesterol.

During follow-up, women in the study had 199 heart attacks, 203 strokes, 63 deaths from heart disease and 312 procedures to open blocked arteries.

After adjusting for traditional heart disease factors, such as blood pressure and total cholesterol, the genetic risk score was not associated with heart disease risk.

Instead, they found that family history of an early heart attack was one of the biggest independent risk factors.

"Our findings confirm the importance of family history of cardiovascular disease, which integrates shared genetics, shared behaviors, and environmental factors," Paynter and colleagues wrote.

"While the importance of genetic data in understanding biology and etiology is unchallenged, we did not find evidence in this study of more than 19,000 women to incorporate the current body of known genetic markers into formal clinical tools for cardiovascular risk assessment," they wrote.

SOURCE: Journal of the American Medical Association, February 17, 2010.