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This information was reviewed and approved by Andrew M. Freeman, MD, FACC, FACP (7/1/2025).

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What Is High Cholesterol?


Some cholesterol is important for your body’s function. But high levels of cholesterol in the blood (high blood cholesterol) can be serious. It can cause fatty deposits, called plaque, to build up in arteries, making blood flow more difficult. High blood cholesterol can be secondary to many diseases and poor lifestyle. It also can contribute too many other forms of disease, most notably heart disease.

There are often no signs or symptoms of high cholesterol (although at very high levels it can sometimes show up with special skin, tendon, or eye findings). Many people don't know that their cholesterol level is too high until they have a heart attack or stroke, unless they have their cholesterol levels checked regularly.

Everyone age 20 and older should have their cholesterol levels checked at least once every five years. If you are at higher risk, your levels may need to be checked more frequently. You and your doctor can discuss how often you should be tested.

Many people wonder if cholesterol is the issue by itself. While important, the overall goal is not to treat numbers, but you as an individual to lower your personal risk for a cardiac event.

Types of Cholesterol

Low-Density Lipoprotein (Bad Cholesterol) and Apolipoprotein B

When too much low-density lipoprotein (LDL) circulates in the blood, it can slowly build up in the inner walls of the arteries that feed blood to the body. Together with other substances, it can form plaque (or atheroma). Plaque is a thick deposit that can narrow the arteries, make them less flexible and limit the amount of blood they can deliver. Some cardiologists refer to this as “sludge in the pipes” or “hardening of the arteries.” This condition is known as atherosclerosis. As the artery narrows and hardens, less blood can get through, causing ischemia, or a lack of necessary nutrients. If a clot or blockage forms in a narrowed artery to the heart or the brain, a heart attack or stroke can result. Sometimes, plaques can rupture depending on their composition, which is the most common cause for a sudden cardiac event.

Apolipoprotein B (ApoB) is a protein found in lipoproteins, which are particles that carry cholesterol and other types of fats in the blood. It's a key component of LDL and other lipoproteins like CLDL and Lp(a). Measuring ApoB levels can be a more accurate way to assess cardiovascular risk than just LDL alone, especially in certain individuals. 

Lp(a) Cholesterol

Lp(a) is another type of blood cholesterol and is mostly genetically determined. A high level of Lp(a) is a significant risk factor for the premature development of fatty deposits in arteries, as well as a problem with the heart valves. Most professional societies recommend checking this test at least once in a lifetime.

High-Density Lipoprotein (Good Cholesterol)

 About one-fourth to one-third of blood cholesterol is carried by high-density lipoprotein (HDL). HDL cholesterol is known as "good" cholesterol, because moderate levels of HDL seem to protect against heart attack. Low levels of HDL (less than 40 mg/dL) may also increase the risk of cardiac events. HDL tends to carry cholesterol away from the arteries and back to the liver, where it's passed from the body — in a way, it "eats" up the bad cholesterol. Importantly, higher levels may not be as protective as we once thought.

Causes

A high level of cholesterol in the blood is due to abnormal levels of lipoproteins, the particles that carry cholesterol in the bloodstream. 

High cholesterol may be related to:

  • Diet (eating a diet high in carbohydrates and fatty foods, and animal products)
  • Genetic factors (having a family history of high cholesterol)
  • Lack of physical activity or sedentary lifestyle
  • Presence of other diseases (diabetes, underactive thyroid, etc.)
  • Weight (being overweight or obese

It is important to note that a healthy lifestyle with moderate physical activity 30 minutes a day combined with a mostly plant-based diet is probably the best, no-cost, and most highly effective option as a first step toward improved cholesterol levels.


Signs and Symptoms


There are typically no symptoms of high cholesterol. However, if your cholesterol levels remain high, you may develop heart disease. At very high levels, it can sometimes show up in special skin, tendon, or eye tests. 


Diagnosis


A complete medical and exposure history is essential for diagnosis. Your doctor will conduct a complete physical exam and ask you questions about your lifestyle, including your family history, your job, your habits, your hobbies, your current medications and your symptoms. When high cholesterol is suspected, your doctor may have you do a number of tests. 

Lab Tests

Blood Test

Since there are usually no signs and symptoms of high blood cholesterol, a blood test is important to diagnose high blood cholesterol. High blood cholesterol is diagnosed by a blood test called a lipoprotein profile or lipid panel.

You might need to fast before your test. Please check with your doctor beforehand. If you need to fast, you cannot eat or drink anything for 10 to 12 hours or more before taking the test. Often people fast after dinner, until blood is drawn in the morning.

The lipoprotein profile or lipid panel can provide information about:

  • Low-density lipoprotein (LDL) or bad cholesterol level
  • High-density lipoprotein (HDL) or good cholesterol level
  • Total cholesterol
  • Triglycerides
  • Lp(a) and ApoB

If it is not possible to get a lipoprotein profile or lipid panel done, knowing your total cholesterol and HDL cholesterol can give you a general idea about your cholesterol levels.


Treatment


Treatment is tailored to your individual risk of developing heart disease. Some people need to have an LDL less than 70 or even 55 mg/dL (or lower), but you and your doctor can work on these plans together. Below is just one example of some treatment goals. As always, consult your doctor for complete information on your individual needs.

Medications

Medication treatment such as statins control but does not "cure" high blood cholesterol. Therefore, you must continue taking your medicine and adhere to a healthy lifestyle to keep your cholesterol level in the recommended range.

The major types of cholesterol-lowering medications are:

  • Bile Acid Sequestrants: Lower LDL cholesterol
  • Ezetimibe: Lowers LDL cholesterol and risk
  • Fibrates: Lower triglycerides and may increase HDL cholesterol
  • Bempedoic Acid: Lowers LDL and risk
  • PCSK9 Inhibitors: Lower LDL cholesterol and risk (usually injected, 2-26 times/year)
  • Statins: Lower LDL cholesterol and risk

Lifestyle Management

Lifestyle changes are the most common treatment for high cholesterol. Lifestyle changes that help lower cholesterol include: 

  • avoiding excess carbohydrates and fatty foods
  • decreasing animal products in the diet
  • increasing exercise

If these lifestyle changes don't produce the necessary result, oftentimes doctors will use medications. 

It is important to note that a healthy lifestyle with moderate physical activity 30 minutes a day combined with a mostly plant-based diet is probably the best, low-cost and most highly effective option as a first step toward improved cholesterol levels.

See a Specialist


Your primary care physician (PCP) can perform the blood tests needed to diagnose high cholesterol. Your PCP may refer you to a cardiologist if they cannot get your cholesterol under control or suspect heart disease.

At National Jewish Health in Denver, Colorado, we have one of the most respected cardiology and prevention programs in Denver and the region. Learn more about our programs or use the button below to make an appointment.


Our Specialists

  • Christopher K. Dyke

    Christopher K. Dyke, MD, FACC

  • Andrew M. Freeman

    Andrew M. Freeman, MD, FACC, FACP

  • Daniel Groves

    Daniel Groves, MD

  • Glenn A. Hirsch

    Glenn A. Hirsch, MD, MHS, FACC

  • Darlene Kim

    Darlene Kim, MD, FACC

  • Minisha Kochar

    Minisha Kochar, MD

  • Camille Triebel

    Camille Triebel, ANP-BC