Background
Cholesterol is a waxy substance found in your blood. Your body needs cholesterol to build healthy cells, but high levels of cholesterol can increase your risk of heart disease.
With high cholesterol, you can develop fatty deposits in your blood vessels. Eventually, these deposits grow, making it difficult for enough blood to flow through your arteries. Sometimes, those deposits can break suddenly and form a clot that causes a heart attack or stroke.
Causes
Cholesterol is carried through your blood, attached to proteins. This combination of proteins and cholesterol is called a lipoprotein. There are different types of cholesterol, based on what the lipoprotein carries. They are:
- Low-density lipoprotein (LDL). LDL, or "bad" cholesterol, transports cholesterol particles throughout your body. LDL cholesterol builds up in the walls of your arteries, making them hard and narrow.
- High-density lipoprotein (HDL). HDL, or "good" cholesterol, picks up excess cholesterol and takes it back to your liver.
Risk factors
Factors that can increase your risk of bad cholesterol include:
- Poor diet. Eating saturated fat, found in animal products, and trans fats, found in some commercially baked cookies and crackers and microwave popcorn, can raise your cholesterol level. Foods that are high in cholesterol, such as red meat and full-fat dairy products, will also increase your cholesterol.
- Obesity. Having a body mass index (BMI) of 30 or greater puts you at risk of high cholesterol.
- Lack of exercise. Exercise helps boost your body's HDL, or "good," cholesterol while increasing the size of the particles that make up your LDL, or "bad," cholesterol, which makes it less harmful.
- Smoking. Cigarette smoking damages the walls of your blood vessels, making them more prone to accumulate fatty deposits. Smoking might also lower your level of HDL, or "good," cholesterol.
- Age. Because your body's chemistry changes as you age, your risk of high cholesterol climbs. For instance, as you age, your liver becomes less able to remove LDL cholesterol.
- Diabetes. High blood sugar contributes to higher levels of a dangerous cholesterol called very-low-density lipoprotein (VLDL) and lower HDL cholesterol. High blood sugar also damages the lining of your arteries.
Complications
If you have too many cholesterol particles in your blood, cholesterol may accumulate on your artery walls. Eventually, deposits called plaques may form. The deposits may narrow — or block — your arteries. These plaques can also burst, causing a blood clot.
High cholesterol can cause a dangerous accumulation of cholesterol and other deposits on the walls of your arteries (atherosclerosis). These deposits (plaques) can reduce blood flow through your arteries, which can cause complications, such as:
- Chest pain. If the arteries that supply your heart with blood (coronary arteries) are affected, you might have chest pain (angina) and other symptoms of coronary artery disease.
- Heart attack. If plaques tear or rupture, a blood clot can form at the plaque-rupture site — blocking the flow of blood or breaking free and plugging an artery downstream. If blood flow to part of your heart stops, you'll have a heart attack.
- Stroke. Similar to a heart attack, a stroke occurs when a blood clot blocks blood flow to part of your brain.
Diagnosis
A blood test to check cholesterol levels — called a lipid panel or lipid profile — typically reports:
- Total cholesterol
- LDL cholesterol
- HDL cholesterol
- Triglycerides — a type of fat in the blood
For the most accurate measurements, don't eat or drink anything (other than water) for nine to 12 hours before the blood sample is taken.
Treatment
Lifestyle changes such as exercising and eating a healthy diet are the first line of defense against high cholesterol. But, if you've made these important lifestyle changes and your cholesterol levels remain high, your doctor might recommend medication.
The choice of medication or combination of medications depends on various factors, including your personal risk factors, your age, your health and possible drug side effects. Common choices include:
- Statins block a substance your liver needs to make cholesterol. This causes your liver to remove cholesterol from your blood. Statins can also help your body reabsorb cholesterol from built-up deposits on your artery walls, potentially reversing coronary artery disease. Tolerance of medications varies from person to person. The common side effects of statins are muscle pains and muscle damage, reversible memory loss and confusion, and elevated blood sugar.
Choices include atorvastatin (Lipitor), fluvastatin (Lescol XL), lovastatin (Altoprev), pitavastatin (Livalo), pravastatin (Pravachol), rosuvastatin (Crestor) and simvastatin (Zocor).
- Bile-acid-binding resins. Your liver uses cholesterol to make bile acids, a substance needed for digestion. The medications cholestyramine (Prevalite), colesevelam (Welchol) and colestipol (Colestid) lower cholesterol indirectly by binding to bile acids. This prompts your liver to use excess cholesterol to make more bile acids, which reduces the level of cholesterol in your blood.
- Cholesterol absorption inhibitors. Your small intestine absorbs the cholesterol from your diet and releases it into your bloodstream. The drug ezetimibe (Zetia) helps reduce blood cholesterol by limiting the absorption of dietary cholesterol. Ezetimibe can be used with a statin drug.
- Injectable medications. A newer class of drugs, known as PCSK9 inhibitors, can help the liver absorb more LDL cholesterol — which lowers the amount of cholesterol circulating in your blood. Alirocumab (Praluent) and evolocumab (Repatha) might be used for people who have a genetic condition that causes very high levels of LDL or in people with a history of coronary disease who have intolerance to statins or other cholesterol medications.
Medications for high triglycerides
If you also have high triglycerides, your doctor might prescribe:
- The medications fenofibrate (TriCor, Fenoglide, others) and gemfibrozil (Lopid) reduce your liver's production of very-low-density lipoprotein (VLDL) cholesterol and speed the removal of triglycerides from your blood. VLDL cholesterol contains mostly triglycerides.
Using fibrates with a stain can increase the risk of statin side effects.
- Niacin. Niacin limits your liver's ability to produce LDL and VLDL cholesterol. But niacin doesn't provide additional benefits over statins. Niacin has also been linked to liver damage and strokes, so most doctors now recommend it only for people who can't take statins.
- Omega-3 fatty acid supplements. Omega-3 fatty acid supplements can help lower your triglycerides. They are available by prescription or over-the-counter.
Information obtained from the Mayo Clinic website.