High cholesterol
Elevated blood cholesterol increases risk of heart disease and stroke.
High cholesterol, medically termed hypercholesterolemia, is a condition defined by an excess of cholesterol circulating in the bloodstream. It falls under the broader categories of hyperlipidemia (elevated blood lipids), hyperlipoproteinemia (elevated lipoproteins), and dyslipidemia (any imbalance in lipid or lipoprotein levels). Cholesterol itself is a fundamental lipid produced by all animal cells, used to construct cell membranes, and serves as the precursor for steroid hormones and bile acids. Because cholesterol does not dissolve in water, it must be transported through the blood plasma inside protein particles called lipoproteins. These lipoproteins are categorized by their density: very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). While all lipoproteins carry cholesterol, elevated levels of non-HDL lipoproteins—particularly LDL—are strongly linked to an increased risk of atherosclerosis and coronary heart disease. Conversely, higher HDL levels are considered protective.
The condition itself produces no direct symptoms. However, persistently high cholesterol over many years drives the gradual buildup of fatty plaques within artery walls, a process known as atherosclerosis. These plaques can narrow arteries or rupture, triggering blood clots that may block blood flow. A sudden blockage in a coronary artery can cause a heart attack; in an artery supplying the brain, it can cause a stroke. Gradual narrowing may lead to tissue ischemia, manifesting as chest pain, temporary vision loss, dizziness, difficulty speaking, or calf pain while walking. Certain inherited forms, such as familial hypercholesterolemia, produce distinctive physical signs like yellowish cholesterol deposits around the eyelids (xanthelasma), white or gray rings in the cornea (arcus senilis), and cholesterol-rich lumps in tendons (xanthomata).
- field
- Medicine, Cardiology, Lipidology
- known_for
- Association with atherosclerosis and coronary heart disease; dietary and medical management of blood cholesterol
- prevalence_in_US
- About 34 million adults in the United States have high blood cholesterol
- measurement_units
- mg/dL (US) or mmol/L (UK, Europe, Canada)
- recommended_UK_limits
- Total cholesterol ≤5 mmol/L; LDL ≤3 mmol/L for healthy adults
Quick Facts
- Field
- Cardiology, internal medicine
- Complications
- Atherosclerosis, thrombosis, embolism, heart attack, stroke, coronary thrombosis, fat embolism, cardiovascular and coronary heart disease
- Duration
- Lifelong
- Causes
- Poor diet, junk food, fast food, diabetes, alcoholism, monoclonal gammopathy, dialysis therapy, nephrotic syndrome, hypothyroidism, Cushing's syndrome, anorexia nervosa
- Differential
- Hyperlipidemia, hypertriglyceridemia
- Prevention
- Healthy lifestyle, exercise, having a healthy diet, avoiding junk food
- Treatment
- Statins
- Medication
- Atorvastatin, simvastatin
- Prognosis
- Good if managed appropriately
Facts from the source article.
Lore & Background
Cholesterol is one of three major classes of lipids produced and used by all animal cells to form membranes. It is the precursor of steroid hormones and bile acids. Since cholesterol is insoluble in water, it is transported in blood plasma within lipoproteins, classified by density: VLDL, IDL, LDL, and HDL. Elevated levels of non-HDL cholesterol, particularly LDL, are associated with increased risk of atherosclerosis and coronary heart disease, while higher HDL levels are protective. Hypercholesterolemia itself is asymptomatic, but longstanding elevation can lead to atherosclerosis—the buildup of fatty plaques in arteries. Over decades, this can cause progressive narrowing or sudden rupture of plaques, leading to heart attack or stroke. Specific physical findings may include xanthelasma palpebrarum, arcus senilis, and xanthomata, especially in familial hypercholesterolemia. Causes are typically a combination of environmental and genetic factors. Diet high in sugar or saturated fats increases total cholesterol and LDL; trans fats reduce HDL while increasing LDL.
Reader's Guide
High cholesterol is a major modifiable risk factor for cardiovascular disease, the leading cause of death worldwide. Its significance lies in the well-established link between elevated LDL or non-HDL cholesterol and the development of atherosclerosis, which can lead to heart attacks, strokes, and peripheral artery disease. The condition is common—affecting about 34 million US adults—and often requires lifelong management. Dietary measures, such as avoiding trans fats and replacing saturated fats with polyunsaturated fats, are recommended for adults. However, in people with very high cholesterol, such as those with familial hypercholesterolemia, diet alone is often insufficient, and lipid-lowering medications are usually required. In severe cases, treatments like LDL apheresis or surgery may be performed. Diagnosis relies on blood lipid measurements, with different thresholds used in the US (mg/dL) versus the UK and Europe (mmol/L). There is no absolute cutoff between normal and abnormal; values must be considered alongside other risk factors. Genetic screening is advised when familial hypercholesterolemia is suspected. The legacy of research on high cholesterol has shaped public health guidelines, dietary recommendations, and pharmaceutical development, though debates persist over the relative predictive value of LDL versus non-HDL cholesterol and the role of dietary cholesterol.
Did You Know?
- About 34 million adults in the United States have high blood cholesterol.
- Higher HDL cholesterol levels are protective against atherosclerosis and coronary heart disease.
- The Lithuanian Jewish population may exhibit a genetic founder effect for a familial hypercholesterolemia mutation dated to the 14th century.
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