Compared with the assessment of traditional risk factors, such as family history and smoking, genetic testing at this time does not offer any additional information about your risk of a heart attack if you're generally healthy.
Case in point: In a 2010 study published in the Journal of the American Medical Association, researchers tested 19,313 healthy white women for 101 gene variations that studies have linked to an elevated risk of cardiovascular disease. Genetic risk scores were calculated based on the number of gene variations present.
During the study, 777 of the participants had a cardiovascular event, including 199 heart attacks, 203 strokes, 63 deaths, and 312 procedures to open blocked arteries. The 10-year risk of such an event was 3 percent in people with the lowest genetic risk score and 3.7 percent in those with the highest score—a small but statistically significant increase.
However, after adjusting for traditional risk factors—including family history, blood pressure, and high-density lipoprotein cholesterol levels—the genetic risk score was no longer predictive of cardiovascular disease.
At this point, routine genetic testing for cardiovascular disease is not recommended. High blood pressure, elevated cholesterol, physical inactivity, obesity, diabetes, smoking, and a family history of heart attacks or strokes remain the strongest predictors of cardiovascular risk in both women and men.
That's not surprising considering many cardiovascular diseases are caused by a complex interaction of perhaps hundreds of genes and lifestyle factors, such as diet, exercise, and alcohol consumption. Genes cannot tell the whole story.
That said, genetic research on heart disease might prove valuable in the future. Right now, it’s providing novel insights into the biology of cardiovascular disease. And researchers continue to uncover previously unknown genetic associations with heart attack and risk factors such as high cholesterol, blood pressure, diabetes and obesity.
It's hoped that one day genetic testing will usher in personalized medicine that aids diagnosis, counseling and treatment of people at risk.
What about direct-to-consumer genetic tests?
While research is ongoing, many companies are promoting direct-to-consumer genetic testing kits with the promise of providing information about your risks of cardiovascular disease. Experts caution that these tests are of questionable value, particularly if there isn’t a health care professional or genetic counselor available to interpret the results. That scenario raises concerns about accuracy of the results and one’s interpretation of them.
Genetic testing can be useful for assessing risk of certain health concerns, for example, testing for the BRCA1 and BRCA2 genes that play into breast cancer. But before you have any genetic testing, it's worthwhile to see a genetic counselor. A genetic counselor is specially trained to educate and support patients in their decisions about genetic testing. Counselors can explain various tests, note the pros and cons, and help interpret test results.
In most cases, genetic tests simply provide a probability that you will develop a disease, not a definitive answer. Finding out about your genome also raises sensitive issues, such as whether relatives do or don’t want to know about familial risks uncovered by genetic testing.
A genetic test is the most valuable when you can do something about the results, such as take preventative measures or receive earlier treatment. Fortunately, when it comes to heart health, we already know steps you can take:
- Eat a diet that is low in saturated fat, sodium and added sugars.
- Choose lots of fresh fruits and vegetables to get your fill of potassium and fiber.
- Have 3.5 ounces of fish (especially fatty fish with omega-3s, such as salmon and sardines) twice a week. Choose skinless poultry and lean meats over fatty options.
- Get 30 minutes or more of moderate aerobic exercise (such as brisk walking) on most days of the week.
- Lose excess weight.
- Quit smoking.
- Reduce stress and get adequate sleep.
By Natasha Persaud
American Heart Association. "Getting Healthy." Available at: http://www.heart.org/HEARTORG/GettingHealthy/GettingHealthy_UCM_001078_SubHomePage.jsp. Accessed: May 15, 2011.
Greenland, et al. “2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic Adults: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines.” Journal of the American College of Cardiology. 2010 Dec 14;56(25):e50-103.
National Society of Genetic Counselors. “FDA Recognizes Role of Genetic Counselors in DTC Testing.” March 9, 2011 news release. Accessed: May 15, 2011.
National Society of Genetic Counselors. "Consumers Should Be Mindful of DTC Genetic Testing." Feb 4, 2010 news release. Accessed: May 15, 2011.
Paynter, N. et al. “Association Between a Literature-Based Genetic Risk Score and Cardiovascular Events in Women.” JAMA Feb 17, 2010—Vol 303.
Thanassoulis, M.D., and Vasan, M.D. “Genetic Cardiovascular Risk Prediction: Will We Get There?.” Circulation. 2010 Nov 30;122(22):2323-34.