What Is High Blood Cholesterol? How is it Treated?

by Food and Drug Administration (FDA)

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What Is High Blood Cholesterol?

Cholesterol levels are determined through chemical analysis of a blood sample taken from a finger prick or from a vein in the arm. Home cholesterol kits, first approved in 1993, test only for total cholesterol levels but are as accurate as tests done in a doctor's office, says Steven Gutman, M.D., director of FDA's division of clinical laboratory devices. "These tests can give a consumer very valuable information when screening for high cholesterol," he says. "But they shouldn't be considered substitutes for a test conducted in a doctor's office." He adds that if test results are elevated, consumers should see a doctor right away for a more refined blood analysis. The National Cholesterol Education Program considers cholesterol testing in a doctor's office to be the preferred way because the patient can get advice immediately about the meaning of the results and what to do.

Besides determining total cholesterol levels, doctors often order a lipoprotein profile that shows the amounts of LDL, HDL, and another type of blood fat called triglycerides. This information gives doctors a better idea of heart disease risk and helps guide any treatment.

Cholesterol levels are measured in milligrams per deciliter (mg/dL). The National Cholesterol Education Program developed the following classifications for people over age 20 who do not have heart disease:

Desirable blood cholesterol — Total blood cholesterol is less than 200 mg/dL; LDL is lower than 130 mg/dL.

Borderline high cholesterol — Total level is between 200 and 239 mg/dL or LDL is 130 to 159 mg/dL.

High blood cholesterol — Total level is greater than 240 mg/dL or LDL is 160 mg/dL or higher. For patients with heart disease, LDL above 100 mg/dL is too high. In addition, an HDL level less than 35 mg/dL is considered low and increases the risk of heart disease.

The main goal of cholesterol treatment is to lower LDL in people without heart disease. If the LDL level is in the "high" category and fewer than two other risk factors for heart disease are present, the goal is an LDL level lower than 160 mg/dL. If two or more risk factors are present, the goal is less than 130 mg/dL. If a patient already has heart disease, LDL levels should be 100 mg/dL or less. By reducing LDL, heart disease patients may prevent future heart attacks, prolong their lives, and slow down or even reverse cholesterol buildup in the arteries, according to the National Heart, Lung, and Blood Institute.

Treating High Blood Cholesterol

When a patient without heart disease is first diagnosed with elevated blood cholesterol, doctors often prescribe a program of diet, exercise, and weight loss to bring levels down. National Cholesterol Education Program guidelines suggest at least a six-month program of reduced dietary saturated fat and cholesterol, together with physical activity and weight control, as the primary treatment before resorting to drug therapy. Typically, doctors prescribe the Step I/Step II diet (see "Food for Thought") to lower dietary fat, especially saturated fat. Many patients respond well to this diet and end up sufficiently reducing blood cholesterol levels. Study data reinforce these benefits. For example, a 1998 Columbia University study examined 103 male and female patients of diverse ages and ethnic backgrounds and found that reducing dietary saturated fat directly affected blood cholesterol. For every 1 percent drop in saturated fat, the study showed a 1 percent lowering of LDL in patients.

But sometimes diet and exercise alone are not enough to reduce cholesterol to goal levels. Perhaps a patient is genetically predisposed to high blood cholesterol. In these cases, doctors often prescribe drugs. The National Cholesterol Education Program estimates that as many as 9 million Americans take some form of cholesterol-lowering drug therapy. The most prominent cholesterol drugs are in the statin family, an array of powerful treatments that includes Mevacor (lovastatin), Lescol (fluvastatin), Pravachol (pravastatin), Zocor (simvastatin), Baycol (cervastatin), and Lipitor (atorvastatin). Many doctors say statin drugs have revolutionized patient care.

"These drugs have had a fantastic impact on cholesterol treatment," says Redonda Miller, M.D., assistant professor of medicine at Johns Hopkins University School of Medicine. "They all lower cholesterol levels, but the side effects are minimal."

A study published in the medical journal Circulation in 1998 showed that statins dramatically lower the risk of dying from heart disease. Research found that for every 10 percentage points cholesterol was reduced, the risk of death from heart disease dropped by 15 percent.

So far, only three of the drugs — Mevacor, Zocor and Pravachol — have been studied in long-term, controlled trials. "Based on existing evidence, [statin drugs] all have similar safety profiles and are effective at lowering cholesterol in appropriately selected patients," says FDA's Orloff. "The difference between drugs lies mainly in their absolute capacity to lower cholesterol — that is, at the highest approved daily doses."

One landmark study completed in 1994, the Scandinavian Simvastatin Survival Study, or 4S, showed a 42 percent reduction in deaths from heart disease and a 30 percent drop in death from all causes over five years in patients with coronary heart disease whose high LDL levels were lowered with Zocor. The West of Scotland study, reported in 1995, revealed similar benefits from lowering LDL levels with Pravachol in patients without heart disease. And the Cholesterol and Recurrent Events (CARE) study, reported in 1996, showed that lowering LDL levels with Pravachol reduced heart attacks and deaths in patients with a previous heart attack but with cholesterol levels relatively average for the general population. This study showed that Pravachol treatment not only reduced death from heart disease but also death from all causes in a group of heart disease patients with average cholesterol levels.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.