Arteriosclerosis, also known as hardening of the arteries, occurs when the arterial walls thicken and then harden as calcium deposits form. If the coronary vessels are affected, this is known as coronary artery disease. Atherosclerosis is another type of hardening of the arteries in which lipids, particularly cholesterol, build up on the side arterial walls. Risk factors for atherosclerosis include cigarette smoking, a high fat/high cholesterol diet, and hypertension.