Hyperlipidemia (High Blood Lipids)

What blood lipids are

Cholesterol and triglycerides do not dissolve in blood, so they travel in particles called lipoproteins:

• LDL (low-density lipoprotein): carries cholesterol into artery walls. The main target of treatment.
• HDL (high-density lipoprotein): helps remove cholesterol from arteries. Higher levels are generally better, but raising HDL with drugs has not been shown to help.
• Triglycerides: the main fat stored for energy; high levels contribute to heart risk and, if very high, pancreatitis.
• Non-HDL cholesterol: total minus HDL; captures all harmful particles.
• Lipoprotein(a), or Lp(a): a largely inherited particle that raises heart risk; measuring it once in adulthood is increasingly recommended.

Lipid levels explained

Targets depend on overall risk. People with heart disease, diabetes or very high risk are treated to lower LDL levels, often under 70 or even 55 mg/dL.

Types of hyperlipidemia

• High LDL cholesterol (hypercholesterolemia): see also high cholesterol.
• High triglycerides (hypertriglyceridemia).
• Mixed (combined) hyperlipidemia: both raised; common with obesity, diabetes and metabolic syndrome.
• Familial hypercholesterolemia (FH): an inherited condition affecting about 1 in 250 people, causing very high LDL from birth and early heart disease if untreated.
• Familial combined hyperlipidemia and other inherited lipid disorders.

Causes and risk factors

Lifestyle

• diets high in saturated fat, trans fat, refined carbohydrates and sugar
• excess alcohol, which especially raises triglycerides
• excess weight, especially around the waist
• physical inactivity
• smoking, which lowers HDL and damages arteries

Medical conditions (secondary causes)

• type 2 diabetes and insulin resistance
• hypothyroidism
• chronic kidney disease and nephrotic syndrome
• liver disease, especially cholestatic liver disease
• pregnancy
• polycystic ovary syndrome

Medicines

Steroids, some diuretics and beta-blockers, retinoids, some antipsychotics, HIV protease inhibitors, immunosuppressants and estrogen (triglycerides).

Genetics

Family history of early heart disease or very high cholesterol suggests an inherited cause.

Symptoms

Hyperlipidemia usually has no symptoms. Signs that may appear with very high levels include:

• xanthelasma: yellow patches on the eyelids
• tendon xanthomas: lumps on the Achilles tendons or knuckles, typical of FH
• eruptive xanthomas: small yellow bumps with very high triglycerides
• corneal arcus: a white ring around the cornea before age 45

Complications produce symptoms: chest pain (coronary artery disease), stroke, leg pain on walking (peripheral artery disease) or severe belly pain (acute pancreatitis) from very high triglycerides.

Diagnosis

A lipid panel blood test measures total cholesterol, LDL, HDL and triglycerides. Fasting is not usually required, except when triglycerides are high.

Who should be tested:

• adults every 4 to 6 years from age 20, more often if risk is raised
• children once between ages 9 and 11 and again between 17 and 21; earlier with a family history of FH or early heart disease

Doctors then estimate your 10-year cardiovascular risk using tools such as the AHA PREVENT calculator, which combine age, sex, blood pressure, diabetes, smoking, kidney function and lipids. A coronary artery calcium scan can refine risk when the decision is uncertain. Tests for secondary causes include thyroid, kidney and liver function and blood sugar.

Treatment

Lifestyle changes

• Eat a heart-healthy diet: more vegetables, fruit, whole grains, beans, nuts, fish and olive oil; less saturated fat (fatty meats, butter, full-fat dairy), trans fat and processed food.
• Add soluble fiber: oats, barley, beans and psyllium lower LDL.
• Cut sugar, refined carbohydrates and alcohol to lower triglycerides.
• Exercise: at least 150 minutes a week of moderate activity.
• Lose weight: 5 to 10% weight loss improves triglycerides and HDL.
• Stop smoking.

Medicines

Statin decisions are based on overall risk, not cholesterol alone. They are recommended for people with cardiovascular disease, LDL of 190 mg/dL or more, diabetes aged 40 to 75, and others with raised 10-year risk.

Statin side effects: muscle aches are the most common complaint, though many are not caused by the statin itself. Serious muscle damage is rare. Statins slightly raise the chance of developing diabetes, but the heart benefit outweighs this in people at risk.

Complications

• coronary artery disease, angina and heart attack
• stroke and transient ischemic attack
• peripheral artery disease
• aortic aneurysm
• acute pancreatitis with very high triglycerides

Living with hyperlipidemia

Recheck lipids 4 to 12 weeks after starting or changing treatment, then every 3 to 12 months. Treatment is usually long term. If you have FH, your parents, siblings and children should be tested.

Frequently asked questions

What causes hyperlipidemia?

It is caused by a combination of diet high in saturated fat and sugar, excess weight, inactivity, alcohol, smoking, conditions such as diabetes and hypothyroidism, certain medicines, and genetics. Inherited forms like familial hypercholesterolemia cause very high LDL from childhood.

Is hyperlipidemia the same as high cholesterol?

Mostly. Hyperlipidemia is the broader term for high blood fats, including high LDL cholesterol, high triglycerides, or both. High cholesterol is one type. Doctors also use dyslipidemia, which includes low HDL.

What are the symptoms of hyperlipidemia?

Hyperlipidemia usually causes no symptoms, which is why blood tests are important. Very high levels can cause yellow fatty deposits on the eyelids or tendons. Symptoms usually appear only when complications such as heart disease or pancreatitis develop.

Can hyperlipidemia be reversed without medication?

Lifestyle changes can lower LDL by about 10 to 20% and triglycerides by more, and are enough for some people. Those with high cardiovascular risk, very high LDL or familial hypercholesterolemia usually also need medicine to reach safe levels.

What is a dangerous cholesterol level?

An LDL of 190 mg/dL (4.9 mmol/L) or higher is very high and often genetic. Triglycerides above 500 mg/dL are severe and raise pancreatitis risk, especially above 1,000 mg/dL. Overall danger depends on your total cardiovascular risk, not one number.