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EPIDEMIOLOGY Heartening News About Coronary Heart Disease PreventionLifestyle Can Reduce Risk More than Expected It is almost a truism that living well—not smoking, keeping weight down, eating a diet high in fish oils and low in saturated fats, exercising, and drinking a half glass of wine a day—is a fine way to prevent heart attacks. But we have not known just how good it is.
When Meir Stampfer first looked at the recent study data, he was encouraged that more than 80 percent of heart attacks could be prevented but surprised that only 3 precent of nurses in the study actually followed a heart-healthy lifestyle. It now appears that as many as four out of five heart attacks could be avoided if people followed a "heart-healthy" lifestyle. A team of HSPH and Brigham and Women's researchers followed the fate of 84,129 women participating in the Nurses' Health Study over the past two decades. They found that those who practiced the heart-virtuous lifestyle were 82 percent less likely to develop coronary heart disease than those who did not. Their findings appear in the July 6 New England Journal of Medicine. What this suggests, says lead author Meir Stampfer, is that a person's ability to avoid heart attacks—and the overall potential for prevention of coronary heart disease in this country—is much greater than previously believed. "If people realize the magnitude of the overall benefit, and assuming these factors have a causal impact, we can reduce coronary heart disease by over 80 percent," says Stampfer, professor and newly appointed chair of epidemiology and nutrition at HSPH. "That really reduces it from the number one cause of death to something that's still important but much less likely to strike." Walking the WalkEarlier studies by the researchers had shown that adopting single behaviors—not smoking, eating a healthy diet, keeping weight down, exercising—could lower a woman's risk of developing heart disease. This is the first to look at the cumulative impact of doing all the right things.But getting people to do just that will be a challenge. Only 3 percent of the nurses in the study actually followed the healthy lifestyle. "The thing of it is, these are nurses. These are women with a demonstrated interest in health," says Stampfer. "We know that the percent of people following the lifestyle is even smaller in the general population—which, if you want to try and look on the bright side, means the potential for benefit is even greater in the general population." Also on the bright side, Stampfer and his colleagues believe that the heart-healthy lifestyle practiced by the 3 percent of nurses is well within the grasp of many Americans. For example, a half an hour of brisk walking a day—or averaged over several days—satisfies the criterion for exercise. And adopting one healthy lifestyle behavior may lead to another. Such behavioral clustering had been considered a nuisance in their single-risk-factor studies—something that had to be adjusted for statistically. Thinking that such clustering might have biological significance, the researchers decided to take a more holistic look. The first step was to identify which behaviors constituted a heart-healthy lifestyle. Having chosen those behaviors—no smoking; weight-maintenance; a diet low in sugars and saturated fats and high in folate, fiber, and fish oils; and moderate exercise and alcohol consumption—they then decided who was practicing optimal behavior in each category. Their guidelines were actually quite lenient, says Stampfer. Former smokers qualified as did women with a body mass index of up to 25. The diet categorization ended up including 40 percent of the women in the study. They then looked to see who went on to develop fatal and non-fatal heart attacks. "We had two competing goals," says Stampfer. "The first was to see how far you could get with heart disease prevention with what I consider lenient guidelines. The other was to see how much you could get if you were really optimal. I couldn't get to that second goal at all because there were too few people who were optimal." Where did the nurses fall off the heart-healthy wagon? "At every stage," says Stampfer. A quarter of them smoke and a "shockingly high number" are overweight. He hopes that the new study—with its enormous statistical punch as well as its message of leniency—will encourage Americans to make needed changes. Action ItemsBut the study needs to be part of a larger educational campaign. Currently, Americans consume enormous quantities of saturated fats in fast foods. Even those who think they are eating healthy diets by cutting back on all sorts of fats may be doing their hearts damage. "I think from a nutrition point of view, we have failed to get the true facts out there," says Stampfer. "The idea that some kinds of fat are bad, therefore anything with fat is bad is just a scientifically unsound message."Researchers also need to educate consumers so they can demand more from the food industry, says Stampfer. The diets of millions of Americans would improve greatly if food manufacturers substituted unsaturated fats for saturated, or trans, fats. For now, a healthy lifestyle is something that everyone can strive for—and achieve, Stampfer says. For those still on the fence, he has even more heartening news. "We saw the 82 percent decrease without taking into account pharmaceutical intervention," he says. "If you combine this with pharmaceutical interventions, you're pushing heart disease way down." —Misia Landau |
