High cholesterol is one of the major controllable risk factors for coronary heart disease, heart attack and stroke.
As your blood cholesterol rises, so does your risk of coronary heart disease. If you have other risk factors such as smoking, high blood pressure or diabetes, this risk increases even further. The greater the level of each risk factor, the more that factor affects your overall risk. Your cholesterol level can be affected by your age, gender, family health history and diet.
When too much LDL (bad) cholesterol circulates in the blood, it can slowly build up in the inner walls of the arteries that feed the heart and brain. Together with other substances, cholesterol can form a thick, hard deposit called plaque that can narrow the arteries and make them less flexible. This condition is known as atherosclerosis. If a clot forms and blocks a narrowed artery, a heart attack or stroke can result. (American Heart Association).