(3 of 9)
The experts were still not quite able to pin the blame on cholesterol, however. Explains Fred Mattson, a leading researcher at the University of California at San Diego, "We were missing a key piece of evidence: no one had ever shown that reducing the level of cholesterol in the blood did any good."
That was the reason for the N.H.L.B.I, study. The elaborate, ten-year program recruited 3,806 men between the ages of 35 and 59, all of whom had cholesterol levels above 265 mg per deciliter of blood (the average for U.S. adults is 215 to 220). Half the men were put on daily doses of cholestyramine, an unpleasant, cholesterol-lowering drug that was mixed with orange juice and taken six times a day. One participant likened taking it to swallowing "orange-flavored sand." Among its side effects: constipation, bloating, nausea and gas. The other half received a similarly gritty placebo. Researchers had decided to use a drug rather than diet to lower cholesterol, because it would have been virtually impossible to control or measure the diet of so many men over so long a period. By the end of the study, the cholestyramine group had achieved an average cholesterol level 8.5% lower than that of the control group and had suffered 19% fewer heart attacks. Their cardiac death rate was a remarkable 24% lower than that of the placebo group.
The lesson is plain, says Dr. Charles Glueck, director of the University of Cincinnati Lipid Research Center, one of twelve centers that participated in the project: "For every 1% reduction in total cholesterol level, there is a 2% reduction of heart-disease risk." This, says Project Director Basil Rifkind, is the evidence scientists have been waiting for. "It is a turning point in cholesterol-heart-disease research."
Convincing though the study was, doctors disagree on its implications. There is no longer any doubt that lives can be saved by lowering cholesterol levels in the blood, but can this be achieved just by improving diet? If so, would healthier eating habits benefit all Americans? According to Columbia University Cardiologist Robert Levy, who directed the study, the answer is yes on both counts. Says Levy: "If we can get everyone to lower his cholesterol 10% to 15% by cutting down on fat and cholesterol in the diet, heart-attack deaths in this country will decrease by 20% to 30%." Other doctors are not so sure, and urge a stricter interpretation of the study. Says Dr. Edward Ahrens, a veteran cholesterol researcher at Rockefeller University: "Since this was basically a drug study, we can conclude nothing about diet; such extrapolation is unwarranted, unscientific and wishful thinking."
One point on which there is no argument is the importance of treating patients who, like the men in the study, have extremely high cholesterol levels. But doctors differ somewhat on when to sound the alarm. Some believe that anyone with a reading over 200 mg should cut back on fat and cholesterol: that would include more than half the U.S. population. A less extreme view is that only people with levels above 240 mg should receive serious attention. Says Rifkind: "People in this group represent only 20% of the population, but they suffer 40% of the heart attacks."