Hyperlipidemia

Definition

Hyperlipidemia, also known as high cholesterol, hyperlipoproteinemia, or dyslipidemia, is a high level of lipids (fats) in the bloodstream. These lipids include cholesterol, cholesterol compounds, phospholipids, and triglycerides, all carried in the blood as part of large molecules called lipoproteins.

Description

Hyperlipidemia affects the way lipids are produced, used, carried in the blood, and disposed of by the body. The three types of hyperlipidemia include:




Hand of a patient with hyperlipidemia, with excessive cholesterol levels in the blood; here causing fatty lumps under the skin.





Hand of a patient with hyperlipidemia, with excessive cholesterol levels in the blood; here causing fatty lumps under the skin.
(Clinical Photography, Central Manchester University Hospitals NHS Foundation Trust, UK/Science Source)

The lipoproteins present in blood plasma that transport lipids belong to the following major groups:

Dangers of hyperlipidemia

People with hyperlipidemia are thought to be more likely to develop heart disease. When individuals have too much cholesterol in the blood, the cholestrol accumulates in arteries, which can lead to their narrowing (atherosclerosis) and, cause heart disease or stroke.

Generally speaking, doctors recommend that LDL levels be low and HDL high. HDL is often called “good cholesterol” and LDL “bad cholesterol,” although this is misleading because neither HDL nor LDL is in fact cholesterol; they are both lipoproteins that transport cholesterol in the blood.

Cholesterol levels

Able to control

What you eat. Certain foods have types of fat that raise your cholesterol level.

Weight. Being overweight tends to increase your LDL level, lower your high-density lipoprotein (HDL) level, and increase your total cholesterol level.

Activity level. Lack of regular exercise can lead to weight gain, which could raise your LDL cholesterol level. Regular exercise can help you lose weight and lower your LDL level. It can also help your raise your HDL level.

Unable to control

Heredity. High blood cholesterol can run in families. An inherited genetic condition (familial hypercholesterolemia) results in very high LDL cholesterol levels. It begins at birth, and may result in a heart attack at an early age.

Age and sex. Starting at puberty, men have lower levels of HDL than women. As women and men get older, their LDL cholesterol levels rise. Younger women have lower LDL cholesterol levels than men, but after age 55, women have higher levels than men.

SOURCE: National Heart, Lung and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services

Demographics

According to the Centers for Disease Control and Prevention (CDC), from 2011 to 2012 approximately 37% of the adult population had LDL levels in the range at which experts recommend cholesterol medication. Nearly 29 million people had total cholesterol levels greater than 240 mg/dl.

Symptoms

High cholesterol by itself does not cause symptoms, so people are generally not aware that their lipid levels are too high.

Diagnosis

Simple blood tests are done to check blood lipid levels. The CDC recommends that people have their cholesterol checked every four to six years after age 20. A lipoprotein test, also called a fasting lipid test, is commonly performed as part of a routine medical examination. The test measures lipid levels and usually reports on four groups:

A total cholesterol value greater than 200 mg/dL is believed to indicate a greater risk for heart disease. A high HDL is desirable, as are low triglycerides. Cardiologists have believed that LDL levels are a better predictor of heart disease, and they determine how your high cholesterol should be treated, although guidelines issued in 2013 shifted focus from LDL to a more comprehensive picture of lifestyle factors, including weight and blood pressure. In the late 2010s, the importance of non-HDL cholesterol as a marker of risk was also noted. This considers other parts of ‘bad’ cholesterol known as IDL, VLDL and lipoprotein(a) as well as LDL-cholesterol.

The ratio of triglycerides to HDL is another marker used to identify risk of heart attack or stroke. The lower the ratio, the better. A TG/HDL ratio less than 2 is ideal. A ratio over 4 has been shown to be a good predictor of developing coronary artery disease and of insulin resistance. It also predicts worse outcomes after acute ischaemic stroke.

In recent years, much more complex cholesterol tests have been developed, which can break down the LDL component into particle sizes, leading to some refinement of analysis of cholesterol levels. Small LDL particles are believed to present an actual risk, whereas large, fluffy LDL particles are protective and associated with low triglycerides. It is possible to have low LDL numbers and yet have a high level of small, dangerous particles. Some experts now believe that testing for LDL-P and apolipoprotein B (apoB) with a test called the NMR test would be a better approach for deciding treatments.

Treatment

Treatment depends on lipid levels, the presence of risk factors for heart disease, and general health. When lipid levels are not balanced, the goal is to bring them under control, and this is done by changing dietary habits. A patient with hyperlipidemia may be given dietary advice such as:

If dietary changes do not correct the hyperlipidemia, a doctor may recommend a course of drug therapy. In the Unites States, men older than age 35 and postmenopausal women are generally candidates for lipid-lowering medications.

Nutrition and dietary concerns

To treat hyperlipidemia, a diet low in total fat, saturated fat, and cholesterol is recommended, along with reducing or avoiding alcohol intake and losing weight. The American Heart Association (AHA) endorses the following dietary recommendations for people with high blood cholesterol:

Categories of appropriate foods include:

These recommendations translate into the following practical dietary guidelines:

QUESTIONS TO ASK YOUR DOCTOR
KEY TERMS
Adipose—
Tissue that contains fat cells.
Artery—
A blood vessel that carries blood from the heart to the body.
Atherosclerosis—
Clogging, narrowing, and hardening of the large arteries and medium-sized blood vessels. Atherosclerosis can lead to stroke, heart attack, eye problems, and kidney problems.
Bile—
A digestive juice secreted by the liver and stored in the gallbladder that helps in the digestion of fats.
Blood plasma—
The pale yellowish, protein-containing fluid portion of the blood in which cells are suspended. Blood plasma is 92% water, 7% protein, and 1% minerals.
Cholesterol—
Soft, waxy substance found among the lipids present in the bloodstream and in all cells of the body.
Extrahepatic—
Originating or occurring outside the liver.
Fatty acid—
Any of a large group of monobasic acids, especially those found in animal and vegetable fats and oils, having the general formula CnH.
Heart attack—
A heart attack occurs when blood flow to the heart muscle is interrupted. This deprives the heart muscle of oxygen, causing tissue damage or tissue death.
Lipids—
Group of chemicals, usually fats, that do not dissolve in water but dissolve in ether.
Lipoproteins—
Proteins present in blood plasma. The five major families are: chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).
Phospholipid—
Any phosphorous-containing lipid, such as lecithin and cephalin, composed mainly of fatty acids, a phosphate group, and a simple organic molecule.
Plant sterols—
Plant sterols are present naturally in small quantities in many fruits, vegetables, nuts, seeds, cereals, legumes, vegetable oils, and other plant sources.
Psyllium—
Psyllium husk comes from the crushed seeds of the Plantago ovata plant, an herb native to parts of Asia, the Mediterranean, and North Africa. Similar to oats and wheat, psyllium is rich in soluble fiber and has been used as a gentle bulk-forming laxative for constipation.
Saturated fat—
A type of fat that comes from animals and that is solid at room temperature.
Sterols—
Any of a group of predominantly unsaturated solid alcohols of the steroid group.
Stroke—
The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or the rupture of an artery to the brain.
Triglyceride—
The storage form of fat consisting of three fatty acids and glycerol. Triglycerides are used by the body to store energy.
Unsaturated fat—
A type of fat derived from plant and some animal sources, especially fish, that is liquid at room temperature.
Whole grain foods—
A grain is considered whole when all three parts—bran, germ, and endosperm— are present. Common whole grain foods include wild rice, brown rice, whole wheat breads and cookies, oatmeal, whole oats, barley, whole rye, bulgar, and popcorn.

Although lowering fat intake is commonly recommended, particularly for those who need to lose weight, it is now recognised that some types of fat and carbohydrates are key to the maintenance of a healthy lipid profile. Replacement of saturated fat with unsaturated fats (monounsaturates and polyunsaturates) and/or high fiber, complex carbohydrates (e.g., whole grain foods) can lower blood cholesterol levels. Diets high in refined carbohydrates or sugar and/or saturated fat are associated with increases in cholesterol and triglyceride levels.

Therapy

The AHA states that, under current guidelines, drug therapy is considered for:

There are several types of drugs available to help lower blood cholesterol levels, and they work in different ways. Some are better at lowering LDL cholesterol, some are good at lowering triglycerides, and others help raise HDL cholesterol. Lipid-lowering medications include:

Doctors have prescribed cholesterol-lowering medications such as statins since the 1980s. Studies have regularly shown a reduction in risk of cardiovascular events with their use. A review of 90,000 statin users by the Medical Research Council in Oxford and the University of Sydney concluded that risk of fatal heart attack or stroke fell by about a third. Changes in recommendations have steadily increased the number of people taking them. In 2016, the U.S. Preventive Services Task Force issued guidelines increasing the number of people who should be screened to see if they could benefit from stains, regardless of whether they have a history of heart disease. A 2017 study concluded that treating asymptomatic people with statins could prevent heart attacks.

There is not universal acceptance of the value of cholesterol-reducing drugs. Some cardiologists worry about the side effects of statins, which can include muscle pain and cognitive disruptions. Others worry that statin research and advertising focuses on relative risk as opposed to absolute risk of heart attacks, allowing much greater claims of effectiveness than are actually the case. They argue that statins are only effective in men who have had a prior heart attack and that they have never been proven effective at reducing heart attacks in women because they have not been as well represented in studies to date. More research is needed to look at their effects on women of moderate risk.

Prognosis

Prognosis depends on the presence of any additional risk factors for heart disease, such as diabetes, high blood pressure, being a male over age 45 or a female over age 55, and having a first-degree female relative diagnosed with heart disease before age 65 or a first-degree male relative diagnosed before age 55 and with obesity. Outcome is also highly related to early diagnosis, treatment, and compliance with therapy.

Prevention

Hyperlipidemia can be prevented by eating a healthy diet, maintaining a normal weight, and being physically active. Everyone can take steps to maintain proper cholesterol levels, although some people have a genetic predisposition to high cholesterol levels. The most important considerations are to eat foods that are low in saturated fat, to exercise regularly, to lose weight if overweight, to avoid smoking, and to get routine medical examinations and cholesterol tests.

See also Coronary heart disease ; Dietary cholesterol ; Fats ; High-fat, low-carb diets ; Triglycerides .

Resources

BOOKS

American Heart Association. American Heart Association Low-Fat, Low-Cholesterol Cookbook: Delicious Recipes to Help Lower Your Cholesterol. 5th ed. New York: Harmony, 2015.

Furman, Richard. Your Cholesterol Matters: What Your Numbers Mean and How You Can Improve Them. Grand Rapids, MI: Revell: 2017.

Koslo, Jennifer. The Heart Healthy Cookbook for Two. Emeryville, CA: Rockridge, 2017.

Roberts, Barbara H. The Truth About Statins. New York: Pocket, 2012.

Rosch, Paul J., editor. Fat and Cholesterol Don't Cause Heart Attacks and Statins Are Not the Solution. Monmouthshire, UK: Columbus, 2016.

Swanson, Karen. The Low Cholesterol Cookbook and Action Plan: 4 Weeks to Cut Cholesterol and Improve Heart Health. Emeryville, CA: Rockridge, 2018.

PERIODICALS

Baez-Duarte, Blanca Guadalupe, Irma Zamora-Gínez, Ramiro González-Duarte, et al. “Triglyceride/HighDensity Lipoprotein Cholesterol (TG/HDL-C) Index as a Reference Criterion of Risk for Metabolic Syndrome (Mets) and Low Insulin Sensitivity in Apparently Healthy Subjects.” Gaceta Médica de México 153, no. 2 (March—April 2017): 152–58.

Deng, Q-W., H. Wang, C-Z. Sun, et al. “Triglyceride to High-Density Lipoprotein Cholesterol Ratio Predicts Worse Outcomes after Acute Ischaemic Stroke.” European Journal of Neurology 24, no. 2 (February 2017): 283–91.

Ravnskov, Uffe, David M. Diamond, Rokura Hama, et al. “Lack of an Association or an Inverse Association Between Low-Density-Lipoprotein Cholesterol and Mortality in the Elderly: A Systematic Review.” BMJ Open 6, no. 6 6 (June 2016): e010401. http://bmjopen.bmj.com/content/6/6/e010401 (accessed May 4, 2018).

Ridker, Paul M., Brendan M. Everett, Tom Thuren, et al. “Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease.” New England Journal of Medicine 377, no. 12 (September 2017):1119–31.

Stuckle, D., et al. “Cholesterol and Mortality.” Annals of Nutrition and Metabolism 66, suppl. 4 (2015): 1–116. DOI: 10.1159/000381654 https://www.karger.com/article/pdf/381654 (accessed May 4, 2018).

WEBSITES

American Heart Association. “Prevention and Treatment of High Cholesterol (Hyperlipidemia).” Heart.org . http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Hyperlipidemia_UCM_434965_Article.jsp (accessed May 4, 2018).

Best Diet Rankings. “DASH Diet.” U.S. News and World Report. https://health.usnews.com/best-diet/dash-diet (accessed March 3, 2018).

Centers for Disease Control and Prevention. “High Cholesterol Facts.” U.S. Department of Health and Human Services. https://www.cdc.gov/cholesterol/facts.htm (accessed May 4, 2018).

Minneapolis Heart Institute Foundation. “Minneapolis Study Finds Most Major Heart Attacks Occur in People with Normal Cholesterol.” American Association for the Advancement of Science (AAAS). https://www.eurekalert.org/pub_releases/2017-04/ah-msf041217.php (accessed May 4, 2018).

National Heart, Lung, and Blood Institute. “Low-Calorie, Lower Fat Alternative Foods.” National Institutes of Health. http://www.nhlbi.nih.gov/health/public/heart/obesity/lose_wt/lcal_fat.htm (accessed March 3, 2018).

Pritkin Longevity Center and Spa. “Pritkin Diet & Eating Plan.” Pritkin.com . https://www.pritikin.com/healthiestdiet/pritikin-eating-plan (accessed March 3, 2018).

ORGANIZATIONS

American Heart Association, 7272 Greenville Ave., Dallas, TX, 75231, (888) 242-8883, help@onlineaha.org, https://www.onlineaha.org .

British Nutrition Foundation, New Derwent House, 69-73 Theobalds Rd., London, United Kingdom, WC1X 8TA, +44 20 7557-7930, postbox@nutrition.org.uk, http://www.nutrition.org.uk .

Centers for Disease Control and Prevention, Division for Heart Disease and Stroke Prevention, 1600 Clifton Rd., Atlanta, GA, 30329-4027, (800) CDC-INFO (232-4636), cdcinfo@cdc.gov, http://www.cdc.gov/dhdsp .

National Heart, Lung, and Blood Institute, Bldg. 31, 31 Center Dr., Bethesda, MD, 20892, (301) 592-8573, nhlbiinfo@nhlbi.nih.gov, http://www.nhlbi.nih.gov .

Monique Laberge, PhD
Revised by Amy Hackney Blackwell, PhD

  This information is not a tool for self-diagnosis or a substitute for professional care.