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.
High cholesterol can be inherited, but it's often the result of unhealthy lifestyle choices, which make it preventable and treatable. A healthy diet, regular exercise and sometimes medication can help reduce high cholesterol.
High cholesterol has no symptoms. A blood test is the only way to detect if you have it.
According to the National Heart, Lung, and Blood Institute (NHLBI), a person's first cholesterol screening should occur between the ages of 9 and 11, and then be repeated every five years after that.
The NHLBI recommends that cholesterol screenings occur every one to two years for men ages 45 to 65 and for women ages 55 to 65. People over 65 should receive cholesterol tests annually.
If your test results aren't within desirable ranges, your doctor might recommend more-frequent measurements. Your doctor might also suggest more-frequent tests if you have a family history of high cholesterol, heart disease or other risk factors, such as diabetes or high blood pressure.
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:
A lipid profile also typically measures triglycerides, a type of fat in the blood. Having a high triglyceride level also can increase your risk of heart disease.
Factors you can control — such as inactivity, obesity and an unhealthy diet — contribute to harmful cholesterol and triglyceride levels. Factors beyond your control might play a role, too. For example, your genetic makeup might make it more difficult for your body to remove LDL cholesterol from your blood or break it down in the liver.
Medical conditions that can cause unhealthy cholesterol levels include:
Cholesterol levels can also be worsened by some types of medications you may be taking for other health problems, such as:
Factors that can increase your risk of unhealthy cholesterol levels include:
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:
The same heart-healthy lifestyle changes that can lower your cholesterol can help prevent you from having high cholesterol in the first place. To help prevent high cholesterol, you can:
A blood test to check cholesterol levels — called a lipid panel or lipid profile — typically reports:
Generally you're required to fast, consuming no food or liquids other than water, for nine to 12 hours before the test. Some cholesterol tests don't require fasting, so follow your doctor's instructions.
In the United States, cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. In Canada and many European countries, cholesterol levels are measured in millimoles per liter (mmol/L). To interpret your test results, use these general guidelines.
| Total cholesterol (U.S. and some other countries) | Total cholesterol* (Canada and most of Europe) | Results |
|---|---|---|
| *Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines. | ||
| Below 200 mg/dL | Below 5.2 mmol/L | Desirable |
| 200-239 mg/dL | 5.2-6.2 mmol/L | Borderline high |
| 240 mg/dL and above | Above 6.2 mmol/L | High |
| LDL cholesterol (U.S. and some other countries) | LDL cholesterol* (Canada and most of Europe) | Results |
|---|---|---|
| *Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines. | ||
| Below 70 mg/dL | Below 1.8 mmol/L | Best for people who have coronary artery disease — including a history of heart attacks, angina, stents or coronary bypass. |
| Below 100 mg/dL | Below 2.6 mmol/L | Optimal for people at risk of coronary artery disease or who have diabetes. Near optimal for people with uncomplicated coronary artery disease. |
| 100-129 mg/dL | 2.6-3.3 mmol/L | Near optimal if there is no coronary artery disease. High if there is coronary artery disease. |
| 130-159 mg/dL | 3.4-4.1 mmol/L | Borderline high if there is no coronary artery disease. High if there is coronary artery disease. |
| 160-189 mg/dL | 4.1-4.9 mmol/L | High if there is no coronary artery disease. Very high if there is coronary artery disease. |
| 190 mg/dL and above | Above 4.9 mmol/L | Very high, likely representing a genetic condition. |
| HDL cholesterol (U.S. and some other countries) | HDL cholesterol* (Canada and most of Europe) | Results |
|---|---|---|
| *Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines. | ||
| Below 40 mg/dL (men) | Below 1.0 mmol/L (men) | Poor |
| Below 50 mg/dL (women) | Below 1.3 mmol/L (women) | |
| 40-59 mg/dL (men) | 1.0-1.5 mmol/L (men) | Better |
| 50-59 mg/dL (women) | 1.3-1.5 mmol/L (women) | |
| 60 mg/dL and above | Above 1.5 mmol/L | Best |
| Triglycerides (U.S. and some other countries) | Triglycerides* (Canada and most of Europe) | Results |
|---|---|---|
| *Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines. | ||
| Below 150 mg/dL | Below 1.7 mmol/L | Desirable |
| 150-199 mg/dL | 1.7-2.2 mmol/L | Borderline high |
| 200-499 mg/dL | 2.3-5.6 mmol/L | High |
| 500 mg/dL and above | Above 5.6 mmol/L | Very high |
For most children, the National Heart, Lung, and Blood Institute recommends one cholesterol screening test between the ages of 9 and 11, and then be repeated every five years after that.
If your child has a family history of early-onset heart disease or a personal history of obesity or diabetes, your doctor might recommend earlier or more-frequent cholesterol testing.
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:
If you also have high triglycerides, your doctor might prescribe:
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. If you decide to take cholesterol medication, your doctor might recommend liver function tests to monitor the medication's effect on your liver.
Diet and exercise are the best initial treatment for children age 2 and older who have high cholesterol or who are obese. Children age 10 and older who have extremely high cholesterol levels might be prescribed cholesterol-lowering drugs, such as statins.
Lifestyle changes are essential to improve your cholesterol levels.
If you're an adult who hasn't had regular cholesterol level checks, make an appointment with your doctor. Here's some information to help you get ready for your appointment.
When you make the appointment, ask if there's anything you need to do in advance. For a cholesterol test, you'll likely have to avoid eating or drinking anything other than water for nine to 12 hours before the blood sample is taken.
Make a list of:
For high cholesterol, some basic questions to ask your doctor include:
Don't hesitate to ask other questions.
Your doctor is likely to ask you a number of questions, such as:
