What is the relationship between cholesterol and heart disease?

If there is too much cholesterol in the blood, some of the excess can become trapped in the artery walls. Over time, this can build up and is called plaque. The plaque can narrow blood vessels and make them less flexible, a condition called arteriosclerosis or “hardening of the arteries.”

This process can happen to blood vessels anywhere in the body, including those of the heart, which are called coronary arteries. If the coronary arteries become partly blocked by plaque, then the blood may not be able to bring enough oxygen and nutrients to the heart muscle.

Some cholesterol-rich plaques are unstable – they have a thin covering and can burst, releasing cholesterol and fat into the bloodstream. The release can cause a clot to form over the plaque, blocking blood flow through the artery.

When arteriosclerosis affects the coronary arteries, the condition is called coronary heart disease or coronary artery disease. Because high blood cholesterol affects the coronary arteries, it is a major risk factor for heart disease. The National Cholesterol Education Program (NCEP) has identified LDL as a primary target of cholesterol-lowering therapy because there is direct evidence that reducing your LDL can help reduce your risk of coronary heart disease. Raising your HDL level is considered good because it can help reduce the risks for heart disease. Conversely, the NCEP has concluded that there is growing evidence that a low HDL level can increase the risk of coronary heart disease.

In addition, according to the 2002 NCEP guidelines, high levels of total cholesterol have been associated with an increased risk of cardiovascular disease.

Risk factors are conditions or behaviors that can increase your chance of developing a disease. Other major heart disease risk factors are listed below.

What are risk factors?

For heart disease, there are two types of risk factors – those you can't change and those you can. Fortunately most of the heart disease risk factors can be changed.

Risk factors you can't change:

• Age – 45 or older for men; 55 or older for women.
• Gender
• Family history of early heart disease – father or brother diagnosed before age 55, or mother or sister diagnosed before age 65.

Risk factors you can change:

• Smoking
• High blood pressure
• High blood cholesterol
• Overweight/obesity
• Physical inactivity
• Diabetes

To visit the National Heart Lung and Blood Institute website and see the full publication on lowering your cholesterol, go to: http://www.nhlbi.nih.gov/health/public/heart/chol/chol_tlc.htm.

Click here for a Cholesterol Goal Tracker and/or a Doctor Discussion Guide to help you when talking to your doctor.