DNA isn’t destiny when it comes to heart attacks. That's at least the takeaway from a new study of more than 55,000 adults published in the New England Journal of Medicine. Even if you’re genetically predisposed to coronary heart disease — the most common type, which often results in heart attacks — you can cut your odds in half by following even a semi-healthy lifestyle.
In one of the most comprehensive studies ever done on genetic versus lifestyle risks, researchers from Massachusetts General Hospital in Boston dug deep into four previous trials of people of various ages and ethnic backgrounds. They assigned each participant a genetic risk score (low, intermediate, or high) based on the 50 gene variants linked to coronary heart disease. Next they evaluated four key lifestyle factors — diet, physical activity, body-mass index, and smoking — and gave everyone a lifestyle risk score of favorable, intermediate, or unfavorable.
In three of the four trials, the genetically predisposed participants who led favorable lifestyles slashed their overall risk of heart attack in half. In the fourth study, which measured plaque buildup in the arteries, an early marker of heart disease, those with high genetic risk and healthy lifestyles had half the plaque buildup as those with risky habits.
Pooling the results of all four studies together revealed that “if you have high genetic risk and unfavorable lifestyle, your heart attack risk over the next 10 years is 11 percent,” says lead researcher Dr. Sekar Kathiresan, director of the Center for Human Genetic Research at Massachusetts General. “But if you have high genetic risk and favorable lifestyle, the risk is only 5 percent. This shows you really do have control over your health.”
In fact, your daily habits likely hold even more sway than this study showed. To earn a favorable lifestyle score, participants had to meet three of four criteria: they don’t smoke, have a BMI of 30 or below (meaning they could be overweight, just not obese), exercise one day a week, and meet six out of 12 dietary recommendations from the American Heart Association. That’s not exactly a tall order. According to Kathiresan, “We likely underestimated the benefits of lifestyle because we set the bar pretty low. If we had set stricter criteria, my guess is the benefits of lifestyle would be even greater.”
On the flipside, if you’re obese, sedentary, a smoker, or an unhealthy eater, you can sabotage low-risk DNA. “We found that your heart attack risk is about the same as someone’s with bad genetics and a good lifestyle,” Kathiresan says. “You may be dealt a good genetic hand, but you can do yourself a lot of harm with bad habits.”
While some people with a family history do everything they can to protect their hearts, Kathiresan says many others automatically equate genetic risk with having zero control. “They’ll say, ‘Oh, my father had a heart attack at age 45 and my brother had one young, so I’m destined to have a problem,” he says. “They’ll think that since they’ll likely have a heart attack anyway, they may as well go out living high.” But this attitude is risky — possibly deadly — so Kathiresan hopes these findings will inspire healthier habits across the board.