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Some studies have explored the utility of DNA to predict risk more accurately. For example, in 2018, researchers published a study in Nature Genetics that showed that variations among individuals at more than 6 million points in their DNA were accurately associated with who had already had a heart attack. However, it remained unclear whether this association with cardiac events that had already taken place could translate into predictive value for future events, as well as how this predictive value compared with calculations made using traditional risk factors.
To answer these questions, the research team from the UT Southwestern Medical Center used data from two long-running studies that follow heart health in thousands of volunteers: the Atherosclerosis Risk in Communities (ARIC) study and the Multi-Ethnic Study of Atherosclerosis (MESA). Because the polygenic risk calculator had been developed using individuals of European descent, the research team included only this population in their own analysis, extracting data on traditional CHD risk factors and genetics from 7,306 individuals ages 45-79. They ran this information through both the ACC/AHA tool and the polygenic risk calculator for these study volunteers at baseline, then checked how these scores compared with which individuals experienced cardiac events over an average of about 15 years.
Their results showed a strong association between polygenic risk scores and CHD, with those scoring highest on this calculator at baseline most likely to experience cardiac events over the follow-up period. However, these results were roughly the same using the ACC/AHA calculator. Although the polygenic risk calculator reclassified about 5% of individuals to a higher or lower risk category, many of these classifications didn’t match who developed CHD or not.
According to the research team, the bottom line is that the polygenic risk score didn’t add much information beyond the ACC/AHA score that could help doctors more accurately predict CHD risk.
The researchers suggest that genetics is an important determinant of familial diseases and a key tool for understanding human biology, and the idea that genetics may also be important for predicting common diseases has been a source of excitement over the past several years. But as an everyday clinical tool for predicting cardiovascular risk, human genetics isn’t there yet. Researchers and clinicians should not lose sight of traditional risk factors for assessing risk of cardiovascular disease, counseling about that risk, and strategizing on reducing it by continuing to also consider traditional cardiovascular risk factors.
Coronary heart disease is the leading cause of death worldwide, killing an estimated 3.8 million men and 3.4 million women each year.
See this sequence on risk factors for coronary heart disease (CHD):