Cholesterol

Description

High blood cholesterol is one of the four major risk factors for coronary heart disease (cigarette smoking, high blood pressure, and sedentary lifestyle are the other three).

High blood cholesterol occurs when there is too much cholesterol in your blood. Your cholesterol level is determined partly by your genetic makeup and the saturated fat and cholesterol in the foods you eat. Even if you didn't eat any cholesterol, your body would manufacture enough for its needs.

The risk of developing coronary heart disease increases as your blood cholesterol level rises. This is why it is so important that you have your blood cholesterol level measured.

Currently, more than half of all adult Americans have blood cholesterol levels of 200 mg/dl or greater, which places them at an increased risk for coronary heart disease.

Approximately 25 percent of the adult population 20 years of age or older has blood cholesterol levels that are considered "high," that is, 240 mg/dl or greater.

Your doctor can measure your level with a blood sample taken from your finger or your arm and will confirm this result with a second test if it is greater 0 than 200 mg/dl.

The following breakdown can help you see how the results of your total blood cholesterol tests relate to your risk of developing coronary heart disease:

Desirable Cholesterol: Less than 200 mg/dl

Borderline High Cholesterol: 200 to 239 mg/dl

High Cholesterol: 240 mg/dl and above

A blood cholesterol level of 240 mg/dl or greater is considered "high" blood cholesterol. But any level above 200 mg/dl, even in the "borderline-high" category, increases your risk for heart disease. If your blood cholesterol is 240 mg/dl or greater, you have more than twice the risk of someone whose cholesterol is 200 mg/dl, and you need medical attention and further testing.

Cholesterol And Heart Disease

When your high blood cholesterol level is combined with another major risk factor (high blood pressure, cigarette smoking, sedentary lifestyle), your risk for coronary heart disease increases even further.

For example, if your cholesterol level is in the "high" category and you have high blood pressure, your risk for coronary heart disease increases six times. If you also smoke, your risk increases more than 20-fold.

Other factors that increase your risk for coronary heart disease include a family history of coronary heart disease before the age of 55, diabetes, vascular (blood vessel) disease, obesity, and being male. Whether your total blood cholesterol is in the "borderline-high" category or "high" category, you should make some changes in your diet and increase your activity levels to lower your cholesterol. If your cholesterol level is desirable, you should have your level checked again in 5 years and take steps to prevent it from rising.

Most coronary heart disease is caused by atherosclerosis, which occurs when cholesterol, fat, and other substances build up in the walls of the arteries that supply blood to the heart. These deposits narrow the arteries and can slow or block the flow of blood. Atherosclerosis is a slow progressive disease that may start very early in life yet might not produce symptoms for many years. Lowering your high blood cholesterol level will slow fatty buildup in the walls of the arteries and reduce your risk of a heart attack and death caused by a heart attack (for more information, see Health Profile on Atherosclerosis).

In the U.S., blood cholesterol levels in men and women start to rise at about age 20. Women's blood cholesterol levels prior to menopause (45 to 60 years) are lower than those of men of the same age. After menopause, however, the cholesterol level of women usually increases to a level higher than that of men.

In men, blood cholesterol levels off around age 50 and the average blood cholesterol level declines slightly after age 50. Since the risk of coronary heart disease is especially high in the later decades of life, reducing blood cholesterol levels may be important in the elderly.

Lowering Cholesterol By Diet

For nearly all patients with high cholesterol, a cholesterol-lowering diet is the first step in therapy. Pharmacologic lipid-lowering therapy is reserved for patients in whom dietary therapy fails, or for patients with severely elevated lipid levels, especially in the presence of severe Coronary Artery Disease. Even patients who require pharmacologic therapy should be placed on a low-cholesterol diet to maximize efficacy.

The goal of diet therapy is to reduce serum cholesterol levels while maintaining a nutritionally complete diet. The cardinal principles of cholesterol-lowering dietary intervention are as follows:

• Reduction of saturated fat intake

• Restriction of dietary cholesterol intake

• Curtailing excess caloric intake in an effort to obtain nearly ideal body weight

Reduction of saturated fat intake is the most important factor in dietary therapy. Saturated fat intake has a profound effect on serum cholesterol levels, perhaps even greater than cholesterol intake. Despite this evidence, Americans typically consume nearly 40 percent of total calories in the form of saturated fats. Also, many food products that are high in saturated fats are labeled as "no cholesterol" products by manufacturers. When saturated fats are replaced by any major nutrients (i.e., polyunsaturated fatty acids, monounsaturated fatty acids, or high-carbohydrate foods), total cholesterol levels fall significantly. Thus, the primary goal of dietary intervention is to significantly limit saturated fat intake.

Use Of Niacin

Niacin's ability to reduce cholesterol levels in the blood has long been recognized, but because it was a vitamin and cannot be patented, no drug company has bothered to test and promote it in the fight against coronary heart disease. But the current National Cholesterol Education Program, which aims to get every adult with high cholesterol identified and treated, has led some doctors to take a hard look at niacin.

Researchers have shown that niacin can achieve a 10 percent reduction in cholesterol for one-third to one-half the cost of other cholesterol-lowering drugs. As a further benefit, niacin therapy appears to raise the protective form of cholesterol, called HDL (for high-density lipoprotein). Thus, drug doses of niacin may help cleanse coronary arteries of obstructing fatty deposits.

Use Of Drugs

There are several medications your physician can prescribe to help you lower your blood cholesterol levels. The report issued by the National Cholesterol Education Program cited the bile acid sequestrants - cholestyramine and colestipol - and nicotinic acid as the drugs of first choice. The report underscored the effectiveness and the long-term safety of these drugs as demonstrated in research studies.

The report also highlighted the availability of a new class of drugs, known as the "statins," which have considerable effectiveness in lowering cholesterol levels. Lovastatin, pravastatin and simvastatin, all known by various brand names, appear to work similarly and have added to the likelihood that physicians will treat hypercholesterolemia with medication.

Evidence suggests that for some individuals these drugs reduce the likelihood of coronary events and improve overall mortality rates. Other drugs cited in the report which were not considered as efficacious in lowering LDL-cholesterol as those mentioned above include gemfibrozil and probucol. All cholesterol-lowering medications should be taken only with the advice of and under the supervision of your physician.

Questions to Ask Your Doctor

Can cholesterol levels change from day to day depending on your diet?

Is there a dietician or some other resource you can recommend to help me obtain information about an appropriate diet?

Do you recommend niacin or any other medications to help lower the cholesterol levels? If so, what are the side effects?

How often should cholesterol level checked?

How can I best begin and sustain a program of regular physical activity?