Hypocholesterolemia

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Hypocholesterolemia
Other namesLow cholesterol
Cholesterol.svg
Formula structure of cholesterol
CausesStatins, hyperthyroidism, adrenal insufficiency, malabsorption, malnutrition, etc.

Hypocholesterolemia is the presence of abnormally low (hypo-) levels of cholesterol in the blood (-emia). A defect in the body's production of cholesterol can lead to adverse consequences as well. Cholesterol is an essential component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity. It is not clear if a lower than average cholesterol level is directly harmful; however, it is often encountered in particular illnesses.

Contents

Presentation

Role in disease

Cholesterolemia and mortality for men and women <50 years and >60 years ColesterolemiaMortalitaE.png
Cholesterolemia and mortality for men and women <50 years and >60 years

With the increased use of medication to suppress cholesterol, some have expressed concern that lowering cholesterol levels excessively will itself cause disease.

Specific disease entities

Demographic studies suggest that cholesterol levels form a U-shape curve when plotted against mortality; this suggests that low cholesterol is associated with increased mortality, mainly due to depression, cancer, hemorrhagic stroke, aortic dissection and respiratory diseases. [1] It is possible that whatever causes the low cholesterol level also causes mortality, and that the low cholesterol is simply a marker of poor health. [2]

Links with depression have been supported by studies. [3] In contrast, no evidence was found for a link with hemorrhagic stroke (although higher cholesterol levels conferred a relative protection), and neither did statin drugs worsen the risk. [4]

The Heart Protection Study found no increase in either respiratory disease or neuropsychiatric illness in a large trial population taking a statin drug. [5]

Elderly

In the elderly, low cholesterol may confer a health risk that may not be offset by the beneficial effects of cholesterol lowering. [6] Similarly, for elderly patients admitted to hospital, low cholesterol may predict short-term mortality. [7] The prevalence of hypocholesterolemia in the elderly ranges between 2% and 36%, depending on specific cutoff levels and age range investigated. [8] Alerting physicians to hypocholesterolemia may benefit some of their patients who take cholesterol-lowering drugs and decrease the rate of their emergency room visits. [9]

Critical illness

In the setting of critical illness, low cholesterol levels are predictive of clinical deterioration, and are correlated with altered cytokine levels. [10]

Causes

Possible causes of low cholesterol are:[ citation needed ]

Diagnosis

Classification

According to the American Heart Association in 1994, only total cholesterol levels below 160 mg/dL or 4.1 mmol/L are to be classified as "hypocholesterolemia". [2] However, this is not agreed on universally and some put the level lower.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Cholesterol</span> Sterol biosynthesized by all animal cells

Cholesterol is the principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.

<span class="mw-page-title-main">Low-density lipoprotein</span> One of the five major groups of lipoprotein

Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons, very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL delivers fat molecules to cells. LDL is involved in atherosclerosis, a process in which it is oxidized within the walls of arteries.

<span class="mw-page-title-main">Statin</span> Class of drugs used to lower cholesterol levels

Statins are the most common cholesterol-lowering drugs. Also known as HMG-CoA reductase inhibitors, they are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease.

Lipid-lowering agents, also sometimes referred to as hypolipidemic agents, cholesterol-lowering drugs, or antihyperlipidemic agents are a diverse group of pharmaceuticals that are used to lower the level of lipids and lipoproteins such as cholesterol, in the blood (hyperlipidemia). The American Heart Association recommends the descriptor 'lipid lowering agent' be used for this class of drugs rather than the term 'hypolipidemic'.

<span class="mw-page-title-main">Scandinavian Simvastatin Survival Study</span>

The Scandinavian Simvastatin Survival Study, was a multicentre, randomized, double-blind, placebo-controlled clinical trial, which provided the initial data that supported the use of the cholesterol-lowering drug, simvastatin, in people with a moderately raised cholesterol and coronary heart disease (CHD); that is people who had previously had a heart attack or angina. The study was sponsored by the pharmaceutical company Merck and enrolled 4,444 people from 94 centres in Scandinavia.

<span class="mw-page-title-main">Fibrate</span> Class of chemical compounds

In pharmacology, the fibrates are a class of amphipathic carboxylic acids and esters. They are derivatives of fibric acid. They are used for a range of metabolic disorders, mainly hypercholesterolemia, and are therefore hypolipidemic agents.

<span class="mw-page-title-main">Cardiovascular disease</span> Class of diseases that involve the heart or blood vessels

Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases, stroke, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, abnormal heart rhythms, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis.

<span class="mw-page-title-main">Hypercholesterolemia</span> High levels of cholesterol in the blood

Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia, hyperlipoproteinemia, and dyslipidemia.

Dyslipidemia is an abnormal amount of lipids in the blood. Dyslipidemia is a risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). ASCVD includes coronary artery disease, cerebrovascular disease, and peripheral artery disease. Although dyslipidemia is a risk factor for ASCVD, abnormal levels don't mean that lipid lowering agents need to be started. Other factors, such as comorbid conditions and lifestyle in addition to dyslipidemia, is considered in a cardiovascular risk assessment. In developed countries, most dyslipidemias are hyperlipidemias; that is, an elevation of lipids in the blood. This is often due to diet and lifestyle. Prolonged elevation of insulin resistance can also lead to dyslipidemia. Likewise, increased levels of O-GlcNAc transferase (OGT) may cause dyslipidemia.

<span class="mw-page-title-main">Heart Protection Study</span>

The Heart Protection Study was a randomized controlled trial run by the Clinical Trial Service Unit, and funded by the Medical Research Council (MRC) and the British Heart Foundation (BHF) in the United Kingdom. It studied the use of the cholesterol lowering drug, simvastatin 40 mg and vitamin supplementation in people who were at risk of cardiovascular disease. It was led by Jane Armitage, an epidemiologist at the Clinical Trial Service Unit.

<span class="mw-page-title-main">Atorvastatin</span> Cholesterol-lowering medication

Atorvastatin, sold under the brand name Lipitor among others, is a statin medication used to prevent cardiovascular disease in those at high risk and to treat abnormal lipid levels. For the prevention of cardiovascular disease, statins are a first-line treatment. It is taken by mouth.

<span class="mw-page-title-main">Simvastatin</span> Lipid-lowering medication

Simvastatin, sold under the brand name Zocor among others, is a statin, a type of lipid-lowering medication. It is used along with exercise, diet, and weight loss to decrease elevated lipid levels. It is also used to decrease the risk of heart problems in those at high risk. It is taken by mouth.

<span class="mw-page-title-main">Rosuvastatin</span> Statin medication

Rosuvastatin, sold under the brand name Crestor among others, is a statin medication, used to prevent cardiovascular disease in those at high risk and treat abnormal lipids. It is recommended to be used together with dietary changes, exercise, and weight loss. It is taken orally.

<span class="mw-page-title-main">Ezetimibe</span> Medication used to treat high cholesterol

Ezetimibe is a medication used to treat high blood cholesterol and certain other lipid abnormalities. Generally it is used together with dietary changes and a statin. Alone, it is less preferred than a statin. It is taken by mouth. It is also available in the fixed combinations ezetimibe/simvastatin, ezetimibe/atorvastatin, ezetimibe/rosuvastatin, and ezetimibe/bempedoic acid.

A polypill is a type of drug combination consisting of a single drug product in pill form and thus combines multiple medications. The prefix "poly" means "multiple", referring to the multiplicity of distinct drugs in a given "pill". In precise usage, a pill is a polypill if it contains at least 4 drugs. An occasional synonym is combopill. A polypill is commonly targets treatment or prevention of chronic conditions.

<span class="mw-page-title-main">Phytosterol</span> Class of steroids derived from plants

Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanols. More than 250 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.

<span class="mw-page-title-main">Torcetrapib</span> Chemical compound

Torcetrapib was a drug being developed to treat hypercholesterolemia and prevent cardiovascular disease. Its development was halted in 2006 when phase III studies showed excessive all-cause mortality in the treatment group receiving a combination of atorvastatin (Lipitor) and torcetrapib.

<span class="mw-page-title-main">Familial hypercholesterolemia</span> Genetic disorder characterized by high cholesterol levels

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein cholesterol, in the blood and early cardiovascular diseases. The most common mutations diminish the number of functional LDL receptors in the liver or produce abnormal LDL receptors that never go to the cell surface to function properly. Since the underlying body biochemistry is slightly different in individuals with FH, their high cholesterol levels are less responsive to the kinds of cholesterol control methods which are usually more effective in people without FH. Nevertheless, treatment is usually effective.

<span class="mw-page-title-main">Colesevelam</span> Pharmaceutical drug

Colesevelam is a bile acid sequestrant administered orally. It was developed by GelTex Pharmaceuticals and later acquired by Genzyme. It is marketed in the U.S. by Daiichi Sankyo under the brand name Welchol and elsewhere by Genzyme as Cholestagel. In Canada it is marketed by Valeant as Lodalis.

The JUPITER trial was a clinical trial aimed at evaluating whether statins reduce heart attacks and strokes in people with normal cholesterol levels.

References

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  2. 1 2 Criqui MH. (1994). Very Low Cholesterol and Cholesterol Lowering. Leaflet 71-0059. American Heart Association.
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  4. Woo D, Kissela BM, Khoury JC, et al. (2004). "Hypercholesterolemia, HMG-CoA reductase inhibitors, and risk of intracerebral hemorrhage: a case-control study". Stroke. 35 (6): 1360–4. doi: 10.1161/01.STR.0000127786.16612.A4 . PMID   15087556.
  5. Heart Protection Study Collaborative Group (2002). "MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial". Lancet. 360 (9326): 7–22. doi:10.1016/S0140-6736(02)09327-3. PMID   12114036. S2CID   35836642.
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  8. Tsabar, Nir; Press, Yan; Rotman, Johanna; Klein, Bracha; Grossman, Yonatan; Vainshtein-Tal, Maya; Eilat-Tsanani, Sophia (2018-01-05). "The low indexes of metabolism intervention trial (LIMIT): design and baseline data of a randomized controlled clinical trial to evaluate how alerting primary care teams to low metabolic values, could affect the health of patients aged 75 or older". BMC Health Services Research. 18 (1): 4. doi:10.1186/s12913-017-2812-0. ISSN   1472-6963. PMC   5755463 . PMID   29301522.
  9. Tsabar, Nir; Press, Yan; Rotman, Johanna; Klein, Bracha; Grossman, Yonatan; Vainshtein-Tal, Maya; Eilat-Tsanani, Sophia (2019-10-12). "A Randomized Trial of Alerting to Hypocholesterolemia Results of the Low Indexes of Metabolism Intervention Trial-C (LIMIT-C)". Journal of the American Medical Directors Association. 21 (3): 410–414. doi:10.1016/j.jamda.2019.08.018. ISSN   1525-8610. PMID   31610995. S2CID   204702775.
  10. Gordon BR, Parker TS, Levine DM, et al. (2001). "Relationship of hypolipidemia to cytokine concentrations and outcomes in critically ill surgical patients". Crit. Care Med. 29 (8): 1563–8. doi:10.1097/00003246-200108000-00011. PMID   11505128. S2CID   8199266.
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