Cholesterol Levels: What the Numbers Mean

Illustration of a blood vessel partially occluded by cholesterol plaque.

Cholesterol is a waxy, fat-like substance that is naturally present in cell walls or membranes everywhere in the body. The body uses cholesterol to produce many hormones, vitamin D, and bile acids that help to digest fat. Too much cholesterol in your bloodstream can lead to narrowing of arteries in the body that cause heart attacks, strokes, and peripheral artery disease.

Cholesterol levels are checked by a simple blood test. This test measures the following:

• total cholesterol,
• low-density lipoproteins (LDL) cholesterol,
• high-density lipoproteins (HDL) cholesterol, and
• triglycerides.

Your health-care professional will be able to help you interpret the blood test results to determine if your cholesterol levels are normal or require treatment.

Too much cholesterol in the body can clog arteries.

Total cholesterol is the sum of all the cholesterol in your blood. Your risk for heart attack and stroke increases with higher cholesterol levels. Other risk factors include smoking, high blood pressure, diabetes, and family history of heart disease or stroke.

HDL (high density lipoprotein) is considered the "good" cholesterol because it may help decrease the cholesterol buildup in the walls of arteries that causes narrowing of their openings.

LDL (low density lipoprotein) is considered "bad" cholesterol. The risk of heart disease goes up if you have a high level of LDL cholesterol in your blood because of increased potential for narrowing of blood vessels.

Triglycerides are another type of fat in the bloodstream. High levels are a risk factor for narrowing arteries in the body.

As described above, high total cholesterol blood levels are associated with an increased risk of heart disease, stroke, and peripheral vascular disease. Depending on the test results, lifelong treatment including healthy lifestyle changes and/or medications may be recommended.

If you have high cholesterol or triglyceride levels, the main goal of a treatment program is to lower the numbers to decrease the potential risk of narrowed arteries and their complications.

• Lifestyle changes include eating a healthy diet low in unsaturated fats and cholesterol, exercise, weight control, and avoiding or quitting smoking.
• Medications may be prescribed in conjunction with lifestyle changes. The health-care professional and patient decide together which medications may be required if lifestyle changes are not adequate to control cholesterol levels. The choice of medication depends upon which type of cholesterol or triglyceride is elevated, past medical history, other illnesses that may be present, and other medications that are being taken.
• Cholesterol control is often a lifelong commitment.
• Other risk factors associated with heart attack, stroke, and peripheral artery disease include smoking, high blood pressure, diabetes, and family history.
• Cholesterol lowering medications may be prescribed even if cholesterol levels are relatively normal, if the risk of developing heart disease or stroke is high. Total cholesterol, HDL cholesterol, blood pressure, blood sugar, and body mass index (BMI) are all assessed by a doctor to determine whether medication may be helpful.

See the following Websites for information on CVD risk calculators:

• American College of Cardiology's Risk Calculator
• National Institutes of Health's Risk Assessment Tool for Estimating Your 10-year Risk of Having a Heart Attack