Over the years, as people grow old, the buildup of fatty material and calcium gets thicker and harder, significantly reducing the blood's flow through an artery. But most of the damage occurs when the a piece of plaque break off. When a piece of plaque breaks off, it can turn into a blood clot that sometimes travels to another part of the body, to a smaller blood vessel in the brain, for example, reducing the flow of oxygen-rich blood to a certain area of the brain and producing memory loss or other cerebral dysfunctions.
Atherosclerosis, or arteriosclerosis, can lead to serious problems, including heart attack, stroke, or even death. Scientists think it begins with damage to the innermost layer of the artery. This layer is called the endothelium. Causes of damage to the arterial wall include elevated levels of cholesterol and triglyceride in the blood, high blood pressure, tobacco smoke, and diabetes. Tobacco smoke greatly worsens atherosclerosis and speeds its growth in the coronary arteries, the aorta and arteries in the legs.