Statins are the most widely used class of cholesterol-lowering drugs. Large, randomized clinical trials have shown—and continue to show—that people who use statins have a 20 percent to 40 percent reduction in death from incidents of major cardiac events in studies lasting two to six years.

The study that really brought statins into the limelight was called the Scandinavian Simvastatin Survival Study, or the 4S trial. It involved 4,444 men and women, ages thirty-five to seventy, who had preexisting heart disease and high total cholesterol levels.

Half took the cholesterol-lowering drug simvastatin for five years, and half took placebo tablets containing no medication. By the end of the trial, LDL levels in the treatment group had fallen by 35 percent and total cholesterol dropped by 25 percent, while no change took place in the placebo group.

The treatment group also had a 30 percent lower chance of dying during the trial and a 34 percent lower chance of having a major coronary event (a nonfatal heart attack or death from coronary heart disease). Other studies that proved statins’ effectiveness in other populations followed in relatively short order.

While the 4S participants all had preexisting heart disease, the 6,595 men who volunteered for the West of Scotland Coronary Prevention Study did not, though they did have high cholesterol.

Those who took a statin (this time one called pravastatin) lowered their LDL and total cholesterol levels by 26 percent and 20 percent, respectively, and their risk of having a major coronary event by 31 percent, compared with those who took placebo tablets.

Then came the Cholesterol and Recurrent Events (CARE) trial. This study of pravastatin therapy involved 4,159 people who had recently had heart attacks but whose LDL cholesterol levels were only modestly elevated (the average was 140–150 mg/dL).

Compared to subjects in the control group, those taking pravastatin for five years were less likely to have a stroke or a second heart attack or need a procedure to open a clogged artery. In the space of just four years, these large studies marshaled powerful evidence of the value of statin drugs in lowering cholesterol.

And more studies continue to confirm this. The Heart Protection Study published in 2002, for example, studied the effect of simvastatin versus placebo in more than twenty thousand people in Great Britain with heart disease or diabetes, but with low enough LDL levels that statins would not necessarily be prescribed.

Half were randomly chosen to receive simvastatin, the other half placebo. The ten thousand people receiving simvastatin had 18 percent fewer deaths from cardiovascular events and a 25 percent reduction in first heart attacks and stroke over the five years of the study.

Even more recently, other studies have shown the benefit of lowering cholesterol levels lower than was previously recommended. These and other studies demonstrated that statins reduce the risk of having a heart attack or other major coronary event for almost everyone—people with and without preexisting heart disease and those with high cholesterol, borderline-high cholesterol, and even normal cholesterol.

This has prompted some to suggest that almost everyone should be taking a statin, and the United Kingdom has recently approved the sale of a statin as an over-thecounter drug. Should everyone be on a statin? The answer is no. First, statins are not approved for use in women who are pregnant because they may cause fetal damage.

Second, statins have side effects that, while rare, are serious. Third, statins are expensive, and many people can achieve acceptable levels of coronary disease risk without using medications at all.

So, I think the message physicians should be bringing to their patients is not that everyone should be on a statin but rather that everyone should know their heart disease risks and be treated if those risks warrant it. A lot more people should probably be on statins than are currently taking them, but these drugs are definitely not for everyone.