Dear Doctor Column, July 26, 2004

Lower Cholesterol to Reduce Risk of Heart Disease

Question:

What should my cholesterol level be? Last time it was checked I think it was about 220, but I'm not sure. How often should it be checked?

Answer:

The American Heart Association (AHA) and the American College of Cardiology endorses the National Cholesterol Education Program (NCEP), a part of the National Institutes of Health, which recommends everyone aged 20 years and older have their cholesterol measured at least once every 5 years. People with abnormal cholesterol levels or high risks for heart disease need more frequent checks.

Because your total cholesterol may be elevated, you should check with your physician and ask for help in interpreting your overall heart disease risk and establishing a time for routine checks of your lipid profile, which includes not only total cholesterol, but also high-density lipoprotein (HDL) and low-density lipoprotein cholesterol (LDL) and triglycerides.

Cholesterol is measured in milligrams per deciliter of blood (mg/dL). To answer your question, in adults, total cholesterol levels of 240 mg/dL or higher are considered high risk; levels from 200 mg/dL to 239 mg/dL are considered borderline high risk; and 240 mg/dL or higher is high blood cholesterol. A person with this level has more than twice the risk of heart disease as someone whose cholesterol is below 200 mg/dL.

But let's back up a bit and talk about cholesterol, what it is, what the numbers mean, why it is important to know our cholesterol levels, and how we can lower our cholesterol and keep it low. Plus, we'll discuss new guidelines issued by the NCEP earlier this month. The new treatment guidelines are for people at high and moderately high risk for a heart attack, including setting lower treatment goals for LDL cholesterol and initiating cholesterol-lower drug therapy at lower LDL thresholds. We'll discuss details of the changes in a moment.

Cholesterol is a soft, waxy substance found among the lipids (fats) in the bloodstream and in all your body's cells. The body needs cholesterol to form cell walls and produce certain hormones, among other essential functions. But a high level of cholesterol in the blood (referred to medically as hypercholesterolemia) confers a major risk for coronary heart disease, the number one killer of women and men in the United States. Each year, more than a million Americans have heart attacks, and about a half million people die from heart disease.

Abnormal cholesterol values do not cause symptoms, so many people are unaware their cholesterol levels are causing problems. It is important to find out precisely what your cholesterol numbers are because correcting abnormal cholesterol levels lessens the risk for developing heart disease and reduces the chance of a heart attack or stroke or dying from the disease, even if you already have it. Cholesterol lowering is important for everyone — younger, middle age, and older adults; women and men; and people with or without heart disease. Your health-care provider must interpret your cholesterol numbers based on other risk factors such as family history of heart disease, race, smoking, high blood pressure, physical inactivity, obesity, and diabetes.

Altered cholesterol levels start doing their damage during the late teens and early adult years. That is when cholesterol begins to accumulate in artery walls, forming plaques that narrow vessels. If you wait until middle age to do something about your cholesterol levels, you will have lost valuable time. Studies have found young adults with lower total cholesterol levels stay healthier and live longer than those with higher cholesterol levels.

But your total cholesterol level does not tell the entire story. What is important is the ratio of "good" HDL to "bad" LDL cholesterol, and the NCEP recommends that HDL and LDL cholesterol be measured along with total cholesterol and triglycerides as part of the initial screening of healthy people aged 20 years and older. Lipoproteins are substances that carry cholesterol through the body. HDL carries cholesterol away from artery walls, while LDL carries cholesterol to the arteries. Consequently, a high HDL cholesterol (60 mg/dL or more) reduces your chance of having a heart attack, while a HDL level below 40 mg/dL increases your risk.

Triglyceride is the most common type of fat in the body and may be checked, as well, depending on risk factors. Many people who have heart disease or diabetes have high triglyceride levels. Normal triglyceride levels vary by age and sex. A high triglyceride level combined with low HDL cholesterol or high LDL cholesterol seems to step up atherosclerosis (the buildup of fatty deposits in artery walls). Atherosclerosis increases the risk for heart attack and stroke.

New NCEP LDL Guidelines

Because of the rising evidence that it is better to have lower cholesterol levels, the NCEP has issued updated guidelines based on a review of five major clinical trials of cholesterol-lowering drugs published since the last guidelines were issued in 2001. The new guidelines were published in the July 13, 2004, issue of Circulation, the Journal of the American Heart Association. By focusing attention on the benefits of reaching much lower LDL cholesterol levels, the new guidelines are expected to intensify treatment of patients at greatest risk for heart attack and also push millions of others at moderate to high-risk of heart disease to begin cholesterol-lowering drug therapy to reduce their LDL cholesterol.

In the updated 2004 guidelines, the NCEP created a new category of patients who should be considered at very high risk and recommended they consider lowering their levels of LDL cholesterol to below 70 mg/dL. Previously, the guidelines recommended such patients reduce their levels to 100 mg/dL or less.

People at very high risk are those who already have heart disease, plus diabetes and high blood pressure, and smoke cigarettes, or also have "metabolic syndrome," a constellation of other risk factors, such as high levels of triglycerides, insulin resistance, and low levels of HDL cholesterol.

High-risk patients are those who have heart disease or diabetes or two or more risk factors, such as smoking and high blood pressure that give them a greater than 20% chance of having a heart attack within 10 years.

The panel also recommended that people at moderately high risk try to cut their LDL levels to at least 100 mg/dL, down from the currently recommended 130 mg/dL. People at moderately high risk are those who have multiple risk factors for coronary heart disease together with a 10% to 20% risk of heart attack within 10 years, which your doctor can help you estimate. Overall, the panel recommended that anyone at high or moderately high risk should try to reduce LDL levels by 30% to 40% through the use of therapeutic lifestyle changes, such as exercise and losing weight and, if needed, cholesterol-lowering drugs.

To view the new guidelines in their entirety, visit the National Blood and Lung Institute's Web site.

The panel also endorsed a combination of diet, exercise, and cholesterol-lowering drugs to cut LDL levels and improve overall cholesterol levels. Most people can significantly improve their risk for developing heart disease, regardless of their age by following the right diet, exercising regularly, losing weight, and not smoking (or being around those who do since active and passive cigarette smoke is a risk factor for heart disease).

The NCEP and AHA offer these additional tips to help you control cholesterol:

• Take control of your health. Know your cholesterol numbers. Be an active partner with your health-care professional in getting and keeping them in control.
• Take control of your grocery shopping. Read food labels and choose foods low in saturated fat and cholesterol.
• Take control of portion sizes. Learn what one serving or portion looks like.
• Take control of your weight. Aim for a healthy weight.
• Take control of your refrigerator. Stock it with fresh fruits, vegetables, and low-fat or fat-free dairy foods.
• Take control of your activity level. Do moderate physical activity, such as brisk walking, for at least 30 minutes on most, and preferably all, days of the week. No time? Do three 10-minute segments on as many days as you can.

For more information, visit the following Web sites:

National Heart, Lung, and Blood Institute; American Dietetic Association; and AHA.