THURSDAY, July 4, 2002 (HealthDayNews) -- If you think you don't have to worry about your blood cholesterol level because it is in the range described as normal and safe, you'd better think again.
That's the revolutionary implication of a major British study showing that a cholesterol-lowering statin drug reduces the incidence of heart attack and stroke in high-risk people, even if they have "normal" or "low" cholesterol readings.
The Heart Protection Study included more than 20,000 Britons aged 40 to 80. All were at more than usual risk of a heart attack or stroke because they had artery disease or diabetes or a previous stroke. Half took daily doses of simvastatin, a statin drug marketed as Zocor, and the other half got a placebo. Zocor's maker, Merck & Co., co-funded the study along with the British Heart Foundation and the U.K. Medical Research Council.
Over five years, the death rate from heart attack and stroke was 18 percent lower for the statin takers than for those in the placebo group, and the incidence of nonfatal heart attacks and strokes was 25 percent lower for the statin takers, says a report in this week's issue of The Lancet. The benefits of the drug were just as great for people whose cholesterol levels were in the "normal" or "low" range, the researchers report.
Doctors had better start revising the definition of low and normal cholesterol levels, says study author Dr. Rory Collins, a professor of medicine and epidemiology at Oxford University. This study was set up to test a hypothesis that prevailing cholesterol levels in Western countries, including Europe and the United States, are dangerously high.
"It's like calling 10 cigarettes a day normal," Collins says. "The epidemiological evidence comparing populations around the world would suggest that the Western average cholesterol level is not normal. The evidence provided here is likely to make people think about the way they have been using statins."
Specifically, he says that anyone at high risk of heart attack or stroke should be prescribed a statin, no matter what his or her cholesterol level. Side effects of the drug are not a problem, since they were minimal in the study, Collins says. By his calculation, putting 10 million high-risk people on statin therapy would save 50,000 lives a year, and would prevent a lot of nonfatal heart attacks and strokes.
The beneficial effect of the statin is almost certainly due to its cholesterol-lowering effect, Collins says. Some studies have indicated that it might have other effects that are good for the arteries, but "there is no reason to invoke such complications," he says.
Dr. Robert O. Bonow, a professor of medicine at Northwestern University School of Medicine and president of the American Heart Association, is not so sure. While bringing down cholesterol levels certainly helps, there are other studies indicating that "another interpretation would be that beneficial effects go beyond the lowering of cholesterol."
Whatever the mechanism, Bonow is impressed by the results. He says the British work is "one of those landmark studies, one that really stands out, a watershed." Some aspects of the study are especially valuable, Bonow says, such as the inclusion of large numbers of older people. "None of the previous studies had given an inkling that it [statin therapy] was efficacious in older people," he says, and the inclusion of large numbers of women was also valuable.
The results will affect the way he practices medicine, Bonow says. "I will now take many of my patients who have documented evidence of artery disease or diabetes, and put them on statin drugs," he says.
Collins and other participants in the study say it is time to re-evaluate the current guidelines on "safe" levels of LDL cholesterol, the "bad" kind that clogs arteries. The current guideline sets the danger level at 130 or above; there is a good case for making it lower, Collins says. The study found a beneficial effect in people with LDL levels under 120. Bonow says such a change will have to be considered by the heart association and other organizations.
One other finding of the study was more evidence that antioxidants such as vitamin C, vitamin E and beta carotene are not effective against cardiovascular disease. Giving supplements to study participants raised their antioxidant blood levels but had no effect on the risk of heart attacks, strokes, cancer or other major problems, the Lancet report says. The best that can be said about antioxidants is that they did not increase the risk of strokes or cancers, which some earlier studies have reported.
The simvastatin findings almost certainly apply to other members of the drug family, the researchers say. The cost of a daily dose of simvastatin is about $1.70 in Britain and $4 a day in the United States, they estimate. However, they note the patent for one widely used drug, lovastatin (Mevacor), expired in Europe at the beginning of the year and the patent for simvastatin will expire in mid-2003 in Europe and in 2006 in the United States, so lower-cost generic versions could become available.
What To Do
You can get the conventional wisdom about blood cholesterol from the American Heart Association, though the strength of this study may alter that thinking. Also, go to the National Heart, Lung, and Blood Institute to find out why you should keep your cholesterol levels low.
