Cholesterol-lowering statin medications have been the number one prescribed class of drugs in the U.S. for years. More than 215 million prescriptions add $14 billion to drug company coffers every year.

A report from the government's National Center for Health Statistics showed that an astounding 25 percent of Americans ages 45 and older take statins, compared to only 2 percent in 1994.

It's not surprising that statins are so popular. Cardiovascular disease (CVD) is the biggest killer of Americans, and "bad" LDL cholesterol is one of the bad guys in this national tragedy, clogging arteries and triggering heart attacks and strokes.

Taking an LDL-lowering statin is a science-proven strategy for people with diagnosed heart disease or other blood vessel blockages.

You're on that list if you have angina or you've had a heart attack, coronary bypass surgery or an artery-widening angioplasty, or a stroke, or you have peripheral arterial disease (clogging of the arteries in the legs).

And possibly if you have diabetes, which damages blood vessels and doubles the risk of heart attack and stroke. In other words, if you already have CVD, an LDL-lowering statin might save your life through what medical experts call secondary prevention.

But most people who take statins haven't been diagnosed with CVD. A blood test simply showed they had high cholesterol, and their doctor prescribed a statin to prevent a heart attack or stroke — a use medical experts call primary prevention.

Shockingly, a new scientific review of 14 studies shows that statins are virtually useless for primary prevention.