Alternative Names hypercholesterolaemia, hyperlipidaemia
Definition High cholesterol is an excessive level of cholesterol in the blood. Hyperlipidaemia is a more general term for high levels of different kinds of fats in the blood. These can result from a diet high in total fat, saturated fats, and cholesterol. Both conditions may also occur as inherited forms.
What is going on in the body? The body produces all the cholesterol it needs, more than 1,000 milligrams on a typical day. When too much cholesterol and other fats are consumed, the body cannot get rid of the excess. As a result, the fats build up in various cells and tissues of the body. High cholesterol can build up on the insides of blood vessel walls. This results in arteriosclerosis, or hardening of the arteries. Blood vessel disease is the most important cause of death and disability in the developed countries. Certain other fats can concentrate in the pancreas and cause painful inflammation.
What are the signs and symptoms of the disease? Any sign of high cholesterol is usually hidden until the major damage is already done. Other conditions that lead to high cholesterol may be more obvious. Obesity and lack of exercise - which often go hand in hand - are the two most important contributors to high cholesterol. Other medical conditions that can result in high cholesterol include:
Certain medications can also increase fat levels. Some of these are:
oestrogens
birth control pills
corticosteroids, such as prednisone
diuretics, or water pills
What are the causes and risks of the disease? Most often, the cause is a diet high in cholesterol and saturated fats. People with any of the following conditions should see their doctor regularly about their cholesterol level:
cirrhosis of the liver
poor control of diabetes
cardiovascular disease
chronic infection
alcohol abuse
chronic infection
underactive thyroid gland
family history of high cholesterol
What can be done to prevent the disease? People should talk to their doctors about how to help prevent or manage high cholesterol. If the person has a family history of high cholesterol or a medical condition that increases the risk, a treatment plan can be suggested. People who are overweight or do not exercise much will be advised to follow a low-fat diet and a regular exercise program.
How is the disease diagnosed? The diagnosis is made by a blood test after an overnight fast. High cholesterol is diagnosed when the total cholesterol is above 5.1 mmols/L (millimoles per litre) of blood. The kind of cholesterol is very important.
LDL cholesterol is the "bad" type. It is linked to blood vessel diseases, heart attacks, and strokes. It should be lower than 3.3 mmols/L.
HDL cholesterol is the "good" type, and is associated with a lower risk of those diseases. It should be 1.0 mmols/L or higher and make up at least 25% of total cholesterol.
What are the long-term effects of the disease? High levels of cholesterol greatly increase the risk of arteriosclerosis, heart disease, and stroke. A total cholesterol level of 7.7 mmols/L doubles the risk of heart attack, for example. Excess fat and cholesterol can be deposited in other areas of the body, causing both medical and cosmetic problems. This is more likely in some of the inherited forms of hyperlipidaemia.
What are the risks to others? High cholesterol does not pose a direct risk to others. Many forms of hyperlipidaemia are inherited, though. Children of affected people may also face the problem of high cholesterol or high fat levels.
What are the treatments for the disease? Anyone with high cholesterol should discuss treatment options with a healthcare professional. The first line of treatment is usually diet and exercise. The person works with his or her doctor to develop the right treatment plan. The person's condition will play a large role in what is prescribed. For example:
People with an underlying medical condition that contributes to high cholesterol may follow a treatment program for that condition.
People who are overweight or eat a high-fat diet will receive information on low-fat diets and a regular exercise program.
People who are not very active can be given a program of regular aerobic exercise. Exercise can both increase "good" HDL cholesterol and lower "bad" LDL cholesterol.
People who have diabetes and are not following their treatment plans may have their doctors recommend certain medications and changes in diet.
People whose cholesterol remains high after these measures may require medications to lower it. These include:
bile acid resins, such as cholestyramine and colestipol, and niacin.
statin drugs are also used. These include atorvastatin, fluvastatin, lovastatin, pravastatin, and simvastatin.
The choice of drugs is based on the cholesterol level, the person's age, and any other problems they have with fats.
What are the side effects of the treatments? The side effects depend on the particular drug chosen. Most cholesterol-lowering drugs can have bad effects on the liver. Blood tests are often done to measure the levels of enzymes produced by the liver.
Niacin can cause flushing of the skin and itching. It may also cause nausea, vomiting, diarrhoea, and high blood sugar.
What happens after treatment for the disease? Any treatment requires repeated measures of the cholesterol level to see how well the program is working. People treated with cholesterol-lowering drugs will require periodic blood tests to check their liver function.
How is the disease monitored? Blood levels of total cholesterol, LDL cholesterol, and HDL cholesterol are measured on a regular basis.
Author: William M. Boggs, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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