By smoking less, watching their cholesterol and lowering their high blood pressure, Americans halved their risk of dying from coronary heart disease over the past 20 years, a new study shows.

While treating existing heart disease also helped reduce mortality rates, preventing heart disease from occurring in the first place made the biggest dent by far.

Coronary heart disease (CHD), or narrowing of the arteries, can lead to chest pain and heart attack. Its main cause is build-up of hard cholesterol deposits in the arteries.

Using data from 1980 through 2000, researchers found that the biggest difference in death rates was due to primary prevention: reducing risk factors among healthy individuals. Smaller impact came from secondary prevention measures such as drugs or surgery for people with heart disease.

The study appears online and in the September issue of the American Journal of Preventive Medicine.

"Knowledge about what has caused these large mortality declines allows us to plan effective measures to reduce disease rates in the future," said lead author Fiona Young, at the Institute of Health and Society at Newcastle University in England.

The researchers gathered data on total cholesterol level, systolic blood pressure and smoking prevalence from The National Health and Nutrition Examination Survey, a yearly national survey representing the entire U.S. population. They entered those statistics into a model that estimates changes in heart disease mortality between two points in time.

People who had not yet had a heart attack accounted for 79 percent of the decrease. The rest came from people with symptoms of heart disease, through secondary prevention measures such as surgery or medication in addition to risk factor control.

"We were surprised by the small proportion of the mortality fall attributable to primary preventive drug interventions such as statins and blood pressure tablets," Young said.

This was partly due to the fact that so few healthy people in a group develop heart problems, even if their risk factors are not treated, she said. And of people who are prescribed these medicines, many either don't take them regularly or stop altogether.

The results prove again that prevention, prevention, prevention is important in staying healthy, according to Paul Sorlie, PhD, chief of the epidemiology branch of the Heart, Lung, and Blood Institute, part of the National Institutes of Health.

"Both primary and secondary prevention are important," he said. "If you don't have CHD, there is a lot you can do to keep healthy by lowering blood pressure and cholesterol, and stop smoking. If you have had a heart attack, you can impact on your future health, prevent a second heart attack, and reduce the risks of dying by working on these risk factors. Don't give up because you have CHD."

"This shows us we are seeing a reduced rate of CHD because we are getting more successful in reducing risk factors," said Nieca Goldberg, MD, cardiologist and spokesperson for the American Heart Association. "The things we have been telling people to do for years really work. This study reminds us of that again."

Young F, et al. Coronary mortality declines in the U.S. between 1980 and 2000: quantifying the contributions from primary and secondary prevention. Am J Prev Med 39(3), 2010.

American Journal of Preventive Medicine

Source: Health Behavior News Service