Risk factors. Medical research shows that certain conditions and habits increase the likelihood that a person will develop CAD. Doctors call these conditions and habits risk factors. There are some risk factors that people cannot control. For example, CAD strikes more men than women and older people more than younger ones. In addition, doctors think that genes are involved in some cases because the disease appears to run in some families.

Coronary artery disease develops when your coronary arteries — the major blood vessels that supply your heart with blood, oxygen and nutrients — become damaged or diseased. Cholesterol-containing deposits (plaque) in your arteries and inflammation are usually to blame for coronary artery disease. When plaques build up, they narrow your coronary arteries, decreasing blood flow to your heart. Eventually, the decreased blood flow may cause chest pain (angina), shortness of breath, or other coronary artery disease signs and symptoms. A complete blockage can cause a heart attack.

People can take steps to control other risk factors involved in coronary artery disease. For example, the most important risk factor is the amount of a fatty substance called cholesterol that people have in their blood. Cholesterol is one of the main fats involved in forming plaques. Doctors have found that the risk of CAD rises as a person's cholesterol level increases. People can help control their cholesterol level by reducing the amount of cholesterol and other animal fats in their diet. For a discussion of healthy cholesterol levels.

CHOLESTEROL. Other controllable risk factors that may cause coronary artery disease include high blood pressure and cigarette smoking. High blood pressure stresses the heart by making it work harder, which may bring on a heart attack. In addition, the force of high blood pressure can break arterial plaques, which can also lead to blood clots and heart attacks. People can lower their blood pressure by losing weight, exercising, reducing alcohol intake, and eating less salt. Certain medicines also help reduce high blood pressure.

Cigarette smokers are more likely to develop CAD than are nonsmokers. Heavy smokers have more than twice the risk of a heart attack that nonsmokers have. But smokers who quit significantly reduce their risk of heart disease. Other risk factors that may contribute to development of coronary artery disease include diabetes, extreme fatness, lack of exercise, and stress.

Regular medical checkups are an important tool in controlling risk of CAD. During examinations, doctors can check a patient's blood pressure and cholesterol level. They can also check the blood for a substance called C-reactive protein. The body releases C-reactive protein when blood vessels leading to the heart are damaged by atherosclerosis. The level of C-reactive protein in the blood helps doctors predict the patient's risk of heart attack. Depending on the results, they may advise people to quit smoking or to follow a special diet to control high blood pressure, cholesterol level, or weight.