Either high LDL cholesterol or low HDL cholesterol may lead to the buildup of cholesterol (plaque) in artery walls. This buildup, called atherosclerosis, hardens and narrows arteries and reduces blood flow to body tissues, including the heart muscle. Atherosclerosis can lead to:

• Coronary artery disease (CAD), which can cause chest pain, heart attack, heart failure, or irregular heartbeat (arrhythmia). For more information, see the topic Coronary Artery Disease.
• Stroke or transient ischemic attack (TIA). Atherosclerosis, when it affects arteries that supply blood to the brain, may lead to a stroke or TIA. For more information, see the topics Stroke and Transient Ischemic Attack (TIA).
• Peripheral arterial disease, which is caused by atherosclerosis in blood vessels that supply blood to the legs, arms, and other parts of the body. Reduced blood flow to the legs may cause pain or cramps in the calf, thigh, or rear end (buttock). For more information, see the topic Peripheral Arterial Disease of the Legs.

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Cholesterol levels naturally increase with age. They also increase after menopause in women and as a result of certain medical conditions, such as diabetes.