low-density lipoprotein cholesterol

cholesterol

(ko-les'te-rol?) [ chole- + sterol] C₂₇H₄₅OH, a monohydric alcohol; a sterol widely distributed in animal tissues and occurring in egg yolks, various oils, fats, myelin in brain, spinal cord and axons, liver, kidneys, and adrenal glands. It is synthesized in the liver and is a normal constituent of bile. It is the principal constituent of most gallstones and of atherosclerotic plaques found in arteries. It is important in metabolism, serving as a precursor to various steroid hormones (e.g., sex hormones, adrenal corticoids).

An elevated blood level of cholesterol increases a person's risks of developing coronary heart disease (CHD). Lowering elevated total blood cholesterol levels and the levels of low-density lipoprotein cholesterol reduces the risk of heart attacks both in persons with a prior history of coronary disease and in asymptomatic individuals. Risk categories and recommended actions are included in the accompanying table. See: table

Cholesterol levels may be decreased by eating a diet that is low in cholesterol and fat and high in fiber; exercising regularly; and taking medications. Drugs used to control cholesterol levels include lovastatin (and other statins); niacin; and bile-acid resins, e.g., cholestyramine.

high-density lipoprotein cholesterol

See: high-density lipoprotein under lipoprotein.

low-density lipoprotein cholesterol

See: low-density lipoprotein under lipoprotein.

non-HDL cholesterol

The total cholesterol minus the HDL cholesterol. It is a risk factor, independent of other cholesterol measurements, for atherosclerotic vascular disease, esp. in patients with diabetes mellitus, triglyceride levels > 200 mg/dL, or people with the metabolic syndrome.

total cholesterol

The sum of low- and high-density lipoproteins. *N/A = not applicable. SOURCE: http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf, from the Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III); National Cholesterol Education Program; National Heart, Lung, and Blood Institute; National Institutes of Health, NIH Pub. No. 02-5215, September 2002.

Suggested Management of Patients with Raised Lipid Levels
• LDL cholesterol is the primary key to treatment. Diet is first-line therapy and drug intervention is reserved for patients considered to be at a higher risk. Continue diet for at least 6 months before initiating drug therapy; use drug therapy in conjunction with diet, not in place of diet. The greater the risk the more aggressive the intervention.
• If there is evidence of coronary heart disease (CHD), do lipoprotein analysis.
• Initially measure total cholesterol and HDL cholesterol levels; based on these results and the presence or absence of other risk factors, determine course of action or proceed to lipoprotein analysis.
• See American Heart Association (AHA) diet, Step I, and AHA diet, Step II.
• Risk factors for atherosclerosis: advanced age, diabetes mellitus, family history, hypertension, male gender, obesity, sedentary lifestyle, tobacco use.
TOTAL AND HDL CHOLESTEROL
Status and Total Cholesterol	HDL Cholesterol	=2 Positive Risk Factors	Recommendations
Desirable (200 mg/dL)	=35 mg/dL	N/A*	• Reassess total and HDL levels in 5 yr.
• Provide information on diet, physical activity, and risk factor reduction.
	=35 mg/dL	N/A	• Do lipoprotein analysis (see below).
Borderline high (200–239 mg/dL)	=35 mg/dL	No	• Reassess total and HDL levels in 1–2 yr.
• Reinforce diet, physical activity, and other risk factor reduction activities.
	=35 mg/dL	Yes	• Do lipoprotein analysis (see below).
High (=240 mg/dL)			• Do lipoprotein analysis (see below).
LIPOPROTEIN ANALYSIS
LDL cholesterol = (total cholesterol - HDL) - (triglycerides ÷ 5)
Status and LDL Cholesterol	=2 Positive Risk Factors	Recommendations
Desirable (130 mg/dL)	N/A	• Reassess total and HDL in 5 yr.
• Provide information on diet, physical activity, and risk factor reduction.
Borderline high-risk (130–159 mg/dL)	No	• Reassess total, HDL, and LDL annually.
• Provide information on Step I diet and physical activity.
High-risk (=160 mg/dL)	Yes	• Clinical workup (history, physical exam, and lab tests) to check for secondary causes or familial disorders.
• Consider risk factors that can be changed.
• Initiate Step I diet; if diet fails, proceed to Step II diet.
• Consider drug therapy if diet fails to obtain desired levels.
• Goal for borderline high-risk patients with =2 negative risk factors is LDL 130 mg/dL.
• Goal for high-risk patients with no other risk factors is LDL 160 mg/dL.
• When there is evidence of CHD, the goal of therapy is to reduce LDL to =100 mg/dL.
	• LDL > 100—Do clinical workup and initiate diet or drug therapy.
	• LDL =100—Individualize instruction on diet and physical activity and repeat lipoprotein analysis annually.

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