Crestor

Metabolism, processing and removal

Cholesterol is oxidized in the liver in various bile acids. [22] This, in turn, conjugated with glycine, taurine, glucuronic acid or sulfate. A mixture of conjugated and conjugated bile acids along with the most cholesterol is derived from the liver with bile. About 95% of bile acids are reabsorbed from the intestine, and the rest is lost in the faeces. [23] excretion and reabsorption of bile acids is the basis of enterohepatic circulation, which is essential for digestion and absorption of food fats. Under certain circumstances, when more concentrated, as in the gallbladder, cholesterol crystallizes and is a major component of most gallstones, although lecithin and bilirubin gallstones also occur less frequently [24].
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[edit] Arrhythmia
Main article: hypercholesterolemia and lipid hypothesis

In accordance with the lipid hypothesis, abnormally high cholesterol (hypercholesterolemia), ie higher concentrations of LDL and lower concentrations of functional HDL are strongly associated with cardiovascular disease because these promote atheroma of the arteries (atherosclerosis). This disease process leads to myocardial infarction (heart attack), stroke and peripheral vascular disease. Since higher blood LDL, especially high concentrations of LDL particles and smaller LDL particle size, contribute to this process than cholesterol particle LDL, [25] LDL particles are often called "bad cholesterol" because they were associated with the formation of atheroma . On the other hand, high concentrations of functional HDL, which can be removed from the cells, cholesterol and atheroma, protect, and sometimes called "good cholesterol". These balances are mostly genetically determined, but may be changed physique, medicines, food choices, as well as other factors [26].

Conditions with elevated concentrations of particles of oxidized LDL, especially "small dense LDL" (sdLDL) particles that are associated with the formation of atheroma in the arterial walls, a condition known as atherosclerosis, which is a major cause of coronary heart disease and other forms of cardiovascular disease. In contrast, particles of HDL (especially large HDL) have been identified as a mechanism by which cholesterol and inflammatory mediators can be removed from atheroma. Increased concentrations of HDL correlate with lower rates of atheroma progressions and even regression. 2007 study combining data on almost 900,000 subjects in 61 cohorts of blood showed that total cholesterol levels have an exponential effect on the cardiovascular and total mortality, with the Association is more pronounced in younger subjects. However, since cardiovascular disease rarely occurs in younger people, the influence of high cholesterol on health is greater in the elderly. [27]

Elevated levels of lipoprotein fractions, LDL, VLDL and IDL are atherogenic (prone to cause atherosclerosis). [28] levels of these fractions, rather than total cholesterol levels, correlated with the degree and progress of atherosclerosis. On the contrary, total cholesterol may be within normal limits, but will mainly consist of small LDL particles and small HDL, under any circumstances atheroma growth rates are still high. In contrast, however, if the number of LDL particles is low (mostly large particles) and a significant proportion of HDL particles are large, then atheroma growth rates are generally low, even negative, for any given total concentration of cholesterol in the blood. [Edit] Recently, after a special analysis of the ideal and the EPIC prospective study found an association between high levels of HDL cholesterol (adjusted for apolipoprotein AI and apolipoprotein B) and increased risk of cardiovascular disease, casting doubt on the cardioprotective role of "good cholesterol "[29]

Some people study with HMG-CoA reductase inhibitors, known as statins, have repeatedly confirmed that changing the structure of the lipoprotein transport from unhealthy to healthy model significantly reduces rates of heart disease, even for people with cholesterol values currently considered low for adults. [Edit] As a result, people with a history of cardiovascular disease may benefit from statins, regardless of their cholesterol levels, [30], and in men without cardiovascular disease have benefited from the reduction of abnormally high levels of cholesterol (primary prevention) [31]. primary prevention among women is practiced only by the expansion of scientific achievements in research on men, [32], as well as in women, none of the large statin trials showed reduction in total mortality and cardiovascular endpoints [33].

1987 Report of the National Cholesterol Education Program, Adult Treatment Panel offers total blood cholesterol level should be: <200 mg / dl a normal level of blood cholesterol, 200-239 mg / dL borderline high,> 240 mg / dl high cholesterol. [34] American Heart Association has a similar set of guidelines for total (Ramadan), blood cholesterol levels and risk of cardiovascular disease: [35]
Level mg / dL level mmol / L Interpretation
<200 <5.0 Desirable level corresponding to lower risk for heart disease
200-240 5.2-6.2 Borderline high risk
> 240> 6.2 High risk

However, as today's testing methods determine LDL ( "bad") and HDL ( "good") cholesterol separately, this simplistic view has become somewhat outdated. The desirable level of LDL is less than 100 mg / dL (2.6 mmol / l) [36], although the new goal <70 mg / dL may be considered at higher risk individuals based on some of the above tests. The ratio of total cholesterol, HDL-another useful measure for much less than 5:1 is considered healthy. It should be noted, typical LDL values for children before fatty strips begin to develop is 35 mg / dL. [Edit]
Reference ranges for blood tests showing normal and optimal levels of HDL cholesterol, LDL and total cholesterol mass and molar concentration, found in orange on the right, ie, among the blood components with a high concentration.

Total cholesterol is defined as the sum of HDL, LDL and VLDL. As a rule, measured only the total, HDL, and triglycerides. For cost reasons, VLDL, usually estimated as one fifth of triglycerides, LDL is measured using the Friedewald formula (or variants): It is estimated, LDL = [total cholesterol] - [total HDL] - [estimated VLDL] . Estimated VLDL and LDL triglycerides greater error above 200 mg / dL. [37] It is important to quickly, at least eight hours before the blood, as the triglyceride level varies significantly with food intake.

Given the widely recognized role of cholesterol in cardiovascular disease, it is surprising that some studies have shown an inverse correlation between cholesterol and mortality. Study of 2009 patients with acute coronary syndrome found the Association of hypercholesterolemia with the best mortality. [38]. In the Framingham Heart Study, in subjects over 50 years, they found an 11% increase overall and 14% increase in cardiovascular mortality at 1 mg / dL per year reduction in total blood cholesterol levels. The researchers explain this phenomenon is the fact that people with serious chronic diseases or cancer, as a rule, lower than normal level of cholesterol in the blood. [39] This explanation is not supported by the monitoring of Vorarlberg and health promotion program in which men of all ages and women over 50 with very low cholesterol are more likely to die of cancer, liver disease and mental illness. This result shows that the low cholesterol effect occurs even among younger respondents, contradicting the previous estimate, among the cohort of older people, which is a proxy server or a marker of weakness occurring with age. [40]

A small group of scientists, united in the International Network of Cholesterol Skeptics continue to question the link between cholesterol and atherosclerosis. [41] Nevertheless, the vast majority of physicians and medical scientists accepts the link as a fact. [42]
[edit] Hypocholesterolemia

Abnormally low levels of cholesterol are called hypocholesterolemia. Investigation of the causes of this condition is rather limited, but some studies suggest a link with depression, cancer and a brain hemorrhage. In general, low levels of cholesterol, seem a consequence of underlying disease, not a cause. [27]
[edit] Cholesterol testing