Smoking increases the risk of coronary artery disease in people who have high cholesterol and other diseases that increase the risk of heart disease, such as high blood pressure and diabetes.

Cigarette smoking lowers HDL ("good") cholesterol. It also injures the lining of the blood vessels and increases the risk of developing blood clots, which contributes to atherosclerosis (hardening of the arteries). Even inhaling others' cigarette smoke (secondhand smoke) has been shown to lower HDL cholesterol.

Studies have shown that HDL levels often go up soon after a person quits smoking. For information on how to quit, see the topic Quitting Smoking.