More than 13 million Americans are taking these medications to lower their cholesterol and hopefully stave off heart disease -- a job the drugs appear to excel at. Statins can lower "bad" LDL cholesterol by 20% to 60%. Over time, this can lower the risk of having a heart attack by about the same amount.
This has doctors and medical researchers debating whether many more people should be on statins than currently fall under treatment guidelines. Some drug companies and doctors have even argued that low doses of the drugs should be available over the counter, as they are in the United Kingdom.
At the same time, other studies are reporting that statins might help prevent or treat a number of noncardiovascular conditions -- including multiple sclerosis, cancer and Alzheimer's disease. With all this news, many may be wondering, "Should I take a statin, just in case?"
Experts, for the most part, will say only, "Maybe."
Most of the people at high risk of cardiovascular disease "are going to be safer and live longer if they're on a statin than if they're not," says Nathan Wong, director of the UC Irvine Heart Disease Prevention Program. But that doesn't hold for people whose risk for heart attacks is very low to begin with, he adds. "I'm not saying that everyone is going to be better on a statin. They need to be used with discretion."
All six statins available today -- atorvastatin (Lipitor), rosuvastatin ( Crestor), simvastatin (Zocor), lovastatin (Mevacor), pravastatin (Pravachol) and fluvastatin (Lescol) -- work by blocking an enzyme called HMG-CoA reductase.
In the liver, blocking this enzyme shuts down cholesterol production and increases the amount of cholesterol the liver takes out of the bloodstream.
But statins also block HMG-CoA reductase in the cells lining blood vessels, where, among other things, they can reduce inflammation.
The anti-inflammatory effect of statins has been on many heart experts' minds since the Nov. 9 announcement of the results of a clinical trial called JUPITER. The trial showed that statin treatment can reduce the risk of heart disease in people with normal cholesterol levels but high levels of inflammation as measured by blood levels of a marker called C-reactive protein (CRP).
A team led by Dr. Paul Ridker of Brigham and Women's Hospital in Boston and Harvard Medical School found that in 8,901 people with high blood CRP levels, rosuvastatin (Crestor) reduced the risk of a heart attack by 54% and the need for bypass surgery or angioplasty by 46% compared with an equal number of people taking a placebo.
There were 68 heart attacks and 131 bypass surgeries/angioplasties in the placebo group, but only 31 and 71, respectively, in the group taking the statin. There were 48% fewer strokes -- 64 versus 33. These effects were so dramatic that regulators stopped the trial, slated to go for four years, after less than two. AstraZeneca, the company that makes Crestor, funded the JUPITER trial.
The results raise an obvious question: Are the cholesterol-lowering effects or the inflammation-reducing effects of statins more important?
Dr. Christopher Cannon, a cardiologist at Brigham and Women's, says they both play a part: "You have to have some cholesterol get into the arteries [and cause damage]. And if you have inflammation that damages the lining of the arteries, the cholesterol gets in more easily."
Inflammation can also encourage plaques to rupture, causing clots that block blood flow. "Both [cholesterol buildup and inflammation] are happening simultaneously, and both are inhibited simultaneously with statins," Cannon says.
Currently, more than 13 million people take statin drugs for elevated LDL cholesterol, and at least 47 million more have cholesterol levels high enough to make them eligible by current National Heart, Lung, and Blood Institute cholesterol guidelines.