8.5: Summary

Atherosclerosis is a disease in which the passageway in arteries becomes progressively damaged and narrowed. The process can begin early in life. If the flow of blood is abruptly blocked by a clot, the clot can cause a heart attack if the affected artery feeds the heart muscle.

If the artery feeds the brain, a clot can cause a stroke. A stroke can also occur from a rupture of an artery that feeds the brain (a hemorrhagic stroke). Such a rupture is generally caused by a defect in the arterial wall and/or high blood pressure.

Atherosclerosis is the main cause of heart disease—the leading cause of death in the U.S. The age-adjusted rate of death from heart disease has fallen dramatically since the 1950s, but heart disease is still our leading cause of death because of the increased proportion of older adults in our population.

Although heart disease is most common among older adults, it’s also a common cause of death among those under age 65. In this younger group, heart disease is more common among men than women, and more common among Blacks than Whites.

The major risk factors in the development of atherosclerosis are genetic predisposition, smoking, high LDL-cholesterol, high blood pressure, and male gender. Smoking markedly increases the risk of a heart attack, even more so for sudden death from a heart attack. Carbon monoxide in the smoke displaces some of the oxygen carried by red blood cells, and nicotine constricts blood vessels. Both effects result in less oxygen delivery to tissues.

Adults age 20 and over are advised to have their blood pressure and blood-cholesterol checked periodically. If either of these measurements is high, they should seek the advice of a physician. The initial blood-cholesterol test is usually one that measures total blood-cholesterol. If this is high, LDL and HDL components of blood-cholesterol are measured. There are effective and inexpensive drugs to treat high blood pressure and high LDL-cholesterol.

The higher the LDL(bad)-cholesterol, the higher the risk of a heart attack. Genetics can be a major factor. Dietary factors also have an effect. Diets rich in soluble fibers tend to lower LDL-cholesterol, and diets rich in saturated fat and trans fat tend to raise LDL-cholesterol.

Low HDL(good)-cholesterol is linked to a higher risk of a heart attack. Men have lower HDL than premenopausal women. People who are sedentary or overweight also have lower HDL; regular exercise and losing excess weight help raise HDL to normal levels.

To lower risk of heart attacks and strokes, we’re advised to not smoke, exercise regularly, include fish in the diet, and follow the dietary guidelines outlined in Chapter 4. These guidelines include advice to: maintain a healthy weight; minimize trans and saturated fat; eat plenty of fruits, vegetables, and whole grains; limit salt intake; and, if you drink alcohol, drink only moderate amounts.

If following the guidelines aren’t enough to bring LDL-cholesterol and blood pressure to normal levels, and/or are too hard to follow, your physician can prescribe effective and inexpensive drugs—but the drugs are effective only if taken diligently.