Healthy living could offset genetics and add years free of heart disease
By Laura Williamson, American Heart Association News
People who follow seven rules for healthy living – such as staying physically active and eating a healthy diet – could offset a high genetic risk for heart disease, according to new research that suggests it could mean as many as 20 extra years of life free of heart disease.
The study, published Monday in the American Heart Association journal Circulation, found people with high cumulative genetic risk scores for heart disease could dramatically lower that risk if they adhered to seven lifestyle modifications, called Life's Simple 7. In addition to eating a heart-healthy diet and moving more, this includes not smoking, maintaining an appropriate weight, and keeping blood glucose, cholesterol and blood pressure levels under control.
The findings are not the first to suggest lifestyle can give a person with high genetic risk a winning edge against heart disease, but they are the first to use a new genetic risk tool to show how much disease-free living a person might gain by taking steps to reduce that risk, said lead study author Natalie Hasbani, a doctoral candidate and graduate research assistant at the University of Texas Health Science Center at Houston.
"It's important to communicate these risks in a way that is truly impactful," she said, "to put it in terms of what the information can do for me." Translating risk reduction into an absolute measure – years lived free of disease – is something more typically done in cancer treatment research, she said. "The hope is that hearing these numbers can convince people to change their behaviors."
This was the first study to use the tool to predict lifetime risk for heart disease and the number of years both Black and white adults might live free of it if they adhered to a set of healthy lifestyle guidelines.
Polygenic risk scores are a relatively new tool that includes all of a person's genetic information rather than individual genes associated with a disease. The scoring is based on the total number of variants that increase heart disease risk found in a person's genetic code, based on studies that compare the genes of people who have the disease with those who don't.
The study calculated heart disease risk for 8,372 white adults and 2,314 Black adults age 45 and older. Overall, it found the risk for developing heart disease during a person's remaining lifetime ranged from 16.6% for those who practiced the healthiest lifestyles to 43.1% for those with the least healthy lifestyles. People with high polygenic risk scores could lower their risk for heart disease by up to 50% by also scoring high on following the healthy lifestyle recommendations, compared to their high genetic risk peers who didn't have healthy lifestyles.
The impact of a healthy lifestyle varied by race. For white adults at high genetic risk, living an ideal lifestyle offered 20.2 more years of heart disease-free living compared to those with the least healthy lifestyles. But Black adults at high risk for heart disease were only able to gain 4.5 disease-free years by living a healthy lifestyle.
However, polygenic risk scoring relies on data culled largely from people of European descent. That means it is less reliable when used to predict risk for Black adults and others of non-European descent whose DNA are not well represented in the data pool, the researchers said.
"We need larger genetic association studies in Black adults if we're going to do better in summarizing their risk," said the study's senior author Paul de Vries, assistant professor at the School of Public Health of the University of Texas Health Science Center at Houston.
In a 2021 scientific statement, the AHA called for greater inclusion of people from diverse ethnicities and ancestry in medical research to create more accurate tools for identifying genetic risk for disease in these groups. Efforts are now underway to collect that data, said Dr. Donald Lloyd-Jones, the AHA's president and chair of the department of preventive medicine at Northwestern University Feinberg School of Medicine in Chicago.
In the meantime, "applying (polygenic risk scores) to someone who is African American or Asian just doesn't work very well," he cautioned. "It has the potential to create real problems with health disparities until we get better data."
Polygenic risk scores may be most useful when used to identify people under the age of 40 who carry a high genetic risk for heart disease and don't know it, Lloyd-Jones said. Decisions about whether someone should take medications such as statins to reduce heart disease risk currently are based upon whether they are likely to develop heart disease within 10 years, which is not typically the case for someone in their 30s but might be for someone with high genetic risk.
"We could be missing opportunities to start treatment earlier when it might have a bigger impact," he said. "But there's not a lot of value in genetic risk scores to date for older people. Once people reach middle age, their personal health behaviors tend to matter a lot more than whatever genes they were born with."
The main message of this study, Lloyd-Jones said, is that "while family history or genetics are important, they don't determine your fate. If you are at high risk, you can lower it by pursuing a healthy lifestyle. Likewise, if you are at lower risk, you can worsen your situation by not controlling behaviors."
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