Why Americans' Cholesterol Levels Are Improving

Americans' cholesterol levels are heading in the right direction, a new study finds. Cholesterol is a waxy substance that can build up in blood vessels and increase a person's risk for heart disease, according to the Centers for Disease Control and Prevention. For example, HDL (high-density lipoprotein) cholesterol, or "good" cholesterol, carries cholesterol to the liver so that it can be flushed from the body, the CDC says.