High cholesterol is an excess of cholesterol in your blood. Cholesterol
is a type of lipid, which is a group of fats and fatlike substances found in
your body and in the foods you eat. A high cholesterol level is often due to a
problem with your lipoproteins (low-density lipoproteins, or LDL, and
high-density lipoproteins, or HDL), which are combinations of cholesterol, fat,
and protein that your body uses to transport cholesterol and fat nutrients in
your blood. The other important lipid nutrient that your body processes and
distributes along with cholesterol is triglyceride, a fat nutrient that your
muscle cells use for energy and that your body stores in your fat tissue for
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Why is high cholesterol a risk factor for coronary artery disease?
An imbalance of these
cholesterol-carrying lipoproteins can lead to a buildup of cholesterol inside
your arteries. Although doctors do not completely understand the process, this
excess cholesterol gets deposited in the walls of your arteries, which
contributes to the development of coronary artery disease. The hard plaque that
forms in your arteries as a result of atherosclerosis is made largely of
Cholesterol is measured in
milligrams per deciliter (mg/dL). The following are
general guidelines for total cholesterol levels:1, 2
LDL carries cholesterol from the liver to
other parts of the body where it is needed for cell repair and other
activities. But under certain conditions, LDL cholesterol builds up in the
walls of the arteries. For this reason, LDL cholesterol is often referred to as
"bad" cholesterol. In general, cholesterol-lowering efforts are most often
aimed at reducing levels of LDL cholesterol to reduce the risk of
atherosclerosis, heart attack, and other complications.
If you do not have a history of heart disease,
then an LDL level of:
Less than 100 mg/dL is considered optimal.
100 to 129 mg/dL is considered near-optimal or above
130 to 159 mg/dL is considered
160 to 189 mg/dL is considered
190 mg/dL and above is considered very high.
For people with a higher risk of heart disease, LDL
goals will be lower. Your LDL goal depends on your risk of heart disease and
stroke. For example, if you are at very high risk, your goal is less than 100
with an optional goal of less than 70. If you are at high risk, your goal is
less than 100. Your risk of heart disease depends on
factors like age, blood pressure, smoking, and if you already have
coronary artery disease or
diabetes, or if you have already had a
heart attack or
High-density lipoprotein (HDL)
HDL cholesterol is often referred to as "good" cholesterol because it
helps remove excess "bad" (LDL) cholesterol from the body. HDL cholesterol
picks up leftover cholesterol from the bloodstream and carries it to the liver
for disposal. Low HDL cholesterol increases the risk of coronary artery
disease, and high levels of HDL cholesterol appear to help protect against
heart disease. If you are at risk for heart disease, it may be beneficial to
raise your HDL cholesterol levels.
An HDL level that is:
60 mg/dL or higher is desirable. It reduces the
risk of heart disease, even if total or LDL cholesterol is
Between 40 and 60 mg/dL is good.
Below 40 mg/dL
is considered low. Low HDL is considered a major risk factor for coronary
artery disease in people who also have high total cholesterol levels.
Triglycerides are another form of fat found in the blood. High
triglyceride levels may contribute to fat buildup in the heart arteries and
increase the risk of developing coronary artery disease (CAD).
The following are general triglyceride guideline levels. A triglyceride
Less than 150 mg/dL is considered
150 to 199 mg/dL is considered
200 to 499 mg/dL is considered
500 mg/dL or greater is considered very high.
Lowering LDL and total cholesterol levels can help lower the
risk of CAD, as well as heart attack, stroke, and death, in many people with
average to high cholesterol levels. People at high risk for CAD are especially
encouraged to keep their cholesterol levels low.
For more information, see the topic High Cholesterol.
Grundy SM, et al. (2001). Executive summary of the
third report of the National Cholesterol Education Program (NCEP) Expert Panel
on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults
(Adult Treatment Panel III). JAMA, 285(19):
Grundy SM, et al. (2004). Implications of recent
clinical trials of the National Cholesterol Education Program Adult Treatment
Panel III Guidelines. Circulation, 110(2): 227-239.
[Erratum in Circulation, 110(6): 763.]
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
Carl Orringer, MD - Cardiology, Clinical Lipidology
July 2, 2010
WebMD Medical Reference from Healthwise
July 02, 2010
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