Heart health: Behavior trumps genetics

NORTHWESTERN (US) — A healthy lifestyle has more impact than genetics on cardiovascular health, according to two new studies.

The majority of people who adopt healthy lifestyle behaviors in young adulthood maintain a low cardiovascular risk profile in middle age.

The five most important behaviors are not smoking, low or no alcohol intake, weight control, physical activity, and a healthy diet.

“Health behaviors can trump a lot of your genetics,” says Donald Lloyd-Jones, chair and professor of preventive medicine at Northwestern University.

“This research shows people have control over their heart health. The earlier they start making healthy choices, the more likely they are to maintain a low-risk profile for heart disease.”

Many young adults who have a low-risk profile for heart disease, often tip into the high-risk category by middle age with high blood pressure, high cholesterol and excess weight, as a result of lifestyle, the first study found.

But more than half of the young adults who followed the five healthy lifestyle factors for 20 years were able to maintain their low-risk profile for heart disease though middle age.

“This means it is very important to adopt a healthy lifestyle at a younger age, because it will impact you later on,” explains Kiang Liu, professor of preventive medicine and lead author of the study.

Adults who reach middle age with a low-risk profile for heart disease garner big benefits: they will live much longer, have a better quality of life, and generate lower Medicare bills.

The study followed 2,336 black and white participants, ages 18 to 30 at baseline, for 20 years. Researchers tracked participants’ diet, physical activity, alcohol consumption, smoking, weight, blood pressure and glucose levels at the baseline year, year seven and year 20.

The participants are part of the CARDIA (Coronary Artery Risk Development in Young Adults) multi-center longitudinal study sponsored by the National Heart, Lung and Blood Institute.

After 20 years, the prevalence of a low-risk profile was 60 percent for participants who followed all five healthy lifestyle factors, 37 percent for four factors, 30 percent for three factors, 17 percent for two, and 6 percent for one or zero. The results were similar for men only, women only, black only, and white only.

“From a public health point of view, this shows we should put more emphasis on promoting a healthy lifestyle in young adulthood,” Liu says.

“We need to educate and encourage younger people to do this now, so they’ll benefit when they get older.”

The second study examined three generations of families from the Framingham Heart Study to determine the heritability of cardiovascular health.

Heritability includes a combination of genetic factors and the effects of a shared environment such as the types of foods that are served in a family.

Only a small percentage of the United States population—8 percent—has ideal levels of all the risk factors for cardiovascular health at middle age.

The study found that only a small proportion of cardiovascular health is passed from parent to child; instead, it appears that the majority of cardiovascular health is due to lifestyle and healthy behaviors.

“What you do and how you live is going to have a larger impact on whether you are in ideal cardiovascular health than your genes or how you were raised,” says Norrina Allen, the lead study author and a postdoctoral fellow in preventive medicine.

The study looked at three generations of families including 7,535 people at age 40 and a separate group of 8,920 people at age 50. The goal was to see who was in ideal cardiovascular health at these two critical periods in middle age.

Both studies build on previous research from the department of preventive medicine that has provided the core for the national definition of cardiovascular health over the past decade, notes Lloyd-Jones.

“We really need to encourage individuals to improve their behavior and lifestyle and create a public health environment so people can make healthy choices,” Lloyd-Jones says.

“We need to make it possible for people to walk more and safely in their neighborhoods and buy fresh affordable fruit and vegetables in the local grocery store. We need physical activity back in schools, widely applied indoor smoking bans and reduced sodium content in the processed foods we eat.

“We also need to educate people to reduce their calorie intake. It’s a partnership between individuals making behavior changes but also public health changes that will improve the environment and allow people to make those healthy choices.”

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