Curtains for heart disease?

"We can end heart disease epidemic in the U.S.," says epidemiologist and world-renowned cardiovascular disease expert Jeremiah Stamler. Stamler's work, which spans more than half a century, has homed in on the causes of cardiovascular disease and the strategies to prevent it. His latest findings demonstrate that diet, exercise, and not smoking can head off most heart attacks and strokes.

Diet is like tobacco, Stamler suggests. "The science is no longer in doubt."

Q: You say that we can now end the heart disease epidemic. What's changed?

A: We've had two major advances. For decades, we've known that three major risk factors for heart disease are smoking, high cholesterol, and high blood pressure. And we've addressed two of the three. Advice to the public on not smoking and on diets that lower cholesterol has had a big impact. Smoking has dropped, and average adult cholesterol levels have declined from about 240 to about 200. We've achieved a national health goal.

But now we know how to solve the third piece of the puzzle--how to lower blood pressure with population-wide improvements in diet and exercise.

Furthermore, we now have, for the first time, data on what happens to people who have none of these three major risk factors. With that knowledge, we can end heart disease as an epidemic. It's that simple.

Q: Haven't researchers estimated the risks of high cholesterol, high blood pressure, and smoking before?

A: Yes. And we learned that the more risk factors you've got, the worse off you are. But the earlier comparisons focused on unfavorable or adverse levels. For example, we compared people with cholesterol of 240 and higher to those who were below 240. But below 240 is not favorable. Below 200 is. And optimal is below 180.

We did the same thing with blood pressure. We compared people with blood pressure of 140 over 90 and above to those whose blood pressures were below. But below 140 over 90 isn't favorable--120 over 80 and lower is. We never looked at people with favorable levels.

Q: Why not?

A: There were just too few people who were low-risk. We wanted men and women who had none of the three major risk factors when our studies began in the late 1960s--people who didn't smoke and who had total cholesterol levels below 200 and blood pressures of 120 over 80 or below. And we wanted people who had no history of diabetes or heart attack.

Those people made up less than ten percent of every group of men we looked at, and about 20 percent of younger women. It wasn't until we screened roughly 400,000 people in two major studies that we could identify enough low-risk people. Our latest studies have tracked them for at least 25 years.

Q: Did they live longer?

A: Yes. The findings were all that we could hope for. For example, for two groups of men who were under age 40 when the study began--about 82,000 men altogether--the long-term death rate from coronary heart disease was reduced by 90 percent for low-risk men compared to all others.

We estimated that these low-risk younger men--freed of the burden of epidemic coronary disease--lived six to ten years longer than the other men. The results were similar for low-risk women. For these people, there was no heart disease epidemic.

Q: How about people who were middle-aged when the study began?

A: We estimated that low-risk middle-aged people would live six years longer than all others. Our results probably also apply to older low-risk people, but we didn't have enough of them to say for sure.

Q: Are you just talking about heart disease?

A: No. The low-risk people also had lower death rates from stroke and cancer. And people who were low-risk in middle age were more likely to sail into older age with a better quality of life, less chronic illness, lower Medicare costs, and no evidence of advanced atherosclerosis in their coronary arteries.

Q: What about other risk factors?

A: Diet is a risk factor, but it isn't readily measured. Overweight is a risk factor beyond its impact on blood cholesterol, blood pressure, and diabetes, but we were unsure of that in the late 1960s. And we measured total instead of LDL--so-called bad--cholesterol because when these large studies started, it was cheaper, easier, and less error-prone to measure. But that's not a problem because total cholesterol mirrors LDL, and it predicts heart disease risk.

Q: Why are so few Americans at low risk?

A: It's interesting--in young adults, average levels are still favorable. Blood pressure averages about 116 over 70 and cholesterol averages about 180. But as people age, their blood pressure and cholesterol rise. In part, that's because we eat too much salt, sugar, and fatty baked goods, red meat, and dairy products. And we eat too many calories and exercise too little.

Now we have a diet that can lower blood pressure and cholesterol and keep both from rising with age. It's called DASH, or Dietary Approaches to Stop Hypertension (see "A DASHing Pyramid," p. 8).