What Is Secondary (Acquired) Hyperlipidemia?

Secondary hyperlipidemia is an abnormal rise in blood lipids (fats), including cholesterol and triglycerides. It does not cause noticeable symptoms, but it can increase the risk of heart attack and stroke. Also known as acquired hyperlipidemia, secondary hyperlipidemia develops as a result of lifestyle, underlying health conditions, or medication. It is diagnosed with a lipid panel blood test that measures fats in the blood. Secondary hyperlipidemia is managed by modifying certain unhealthy behaviors and using cholesterol-lowering drugs.

Symptoms

Hyperlipidemia does not cause specific symptoms, but it can have effects on your body.

Many of these effects are related to the build-up of fatty deposits in the blood vessels (atherosclerosis), which can lead to high blood pressure (hypertension), heart attack, stroke, and other related conditions.

If you have atherosclerosis or hypertension, you can experience shortness of breath and fatigue, particularly with exertion.

Advanced hyperlipidemia can cause:

• Yellowish fatty nodules under the skin called xanthomas, especially around the eyes, knees, and elbows
• Pain or a feeling of fullness in the right upper abdomen caused by enlargement of the liver
• Pain or fullness in the left upper abdomen associated with enlargement of the spleen
• The development of a light-colored ring around the cornea called arcus senilis

Causes

Healthcare providers sometimes classify the causes of secondary hyperlipidemia according to the four D's: diet, disorders of metabolism, diseases, and drugs. Unlike primary hyperlipidemia, which is an inherited disorder, the causes of secondary hyperlipidemia are usually modifiable.

Diet

This includes eating too much food that raises "bad" low-density lipoprotein (LDL) cholesterol rather than "good" high-density lipoprotein (HDL) cholesterol. Excessive amounts of saturated fat and trans fats from red meat, processed meats, commercial baked goods, and fried foods can contribute to secondary hyperlipidemia.

Risk factors such as smoking and heavy alcohol use also may contribute to the development and severity of secondary hyperlipidemia.

Metabolic Disorders and Diseases

A metabolic disorder involves hormone disruptions. It may be acquired, such as metabolic syndrome and insulin resistance, or congenital, such as type 1 diabetes.

In either instance, hyperlipidemia that arises as a result of a metabolic disorder is considered secondary even if the cause of the disorder is genetic.

Several metabolic disorders are associated with secondary hyperlipidemia:

• Diabetes mellitus (including type 1 diabetes, type 2 diabetes, and prediabetes) is associated with abnormal increases in triglycerides and very low density lipoprotein (VLDL) cholesterol.
• Kidney diseases (including kidney failure, cirrhosis, chronic hepatitis C, and nephrotic syndrome) are associated with high triglycerides and VLDL.
• Hypothyroidism (low thyroid function) is associated with high LDL.
• Cholestatic liver disease (in which bile ducts are damaged) is linked to high LDL.

Certain autoimmune diseases such as Cushing's syndrome and lupus also are associated with secondary hyperlipidemia. Sometimes eating disorders such as anorexia nervosa can cause abnormal elevations of total cholesterol and LDL.

Drugs

Some medications may impair hormone-producing glands, alter the chemistry of blood, or interfere with how lipids are cleared from the body.

The body uses cholesterol to produce hormones such as estrogen, testosterone, and cortisol. Drugs that increase hormone levels, such as hormone replacement therapy for treating menopause, can cause cholesterol to accumulate because the body no longer needs it to synthesize hormones.

Among the drugs associated with secondary hyperlipidemia:

• Estrogen tends to raise the levels of triglycerides and HDL.
• Birth control pills can raise cholesterol levels and increase the risk of atherosclerosis, depending on the type and the progestin/estrogen dosage.
• Beta-blockers, a class of drugs commonly prescribed for treating high blood pressure, glaucoma, and migraines, typically elevate triglycerides while lowering HDL.
• Retinoids, used to manage psoriasis and certain types of skin cancer, may increase LDL and triglyceride levels.
• Diuretic drugs, used to reduce the buildup of body fluids, typically causes an increase in both LDL and triglyceride levels.

Diagnosis

Hyperlipidemia, both primary and secondary, is diagnosed with a lipid panel. This blood test measures lipids in the blood after fasting for around 12 hours.

The lipid panel is measured in values of milligrams per deciliters (mg/dL).

According to the Centers for Disease Control and Prevention (CDC), the desirable values for cholesterol and triglycerides are:

• Total cholesterol: about 150 mg/dL
• LDL cholesterol: about 100 mg/dL
• Triglycerides: less than 150 mg/dL
• HDL cholesterol: greater than or equal to 40 mg/dL in men and 50 mg/dL in women

Treatment

Because secondary hyperlipidemia is acquired, an important aspect of treatment is lifestyle modification. Cholesterol-lowering drugs also are key.

Most of the underlying metabolic causes, like diabetes and hypothyroidism, are chronic and are not so much "cured" as they are controlled. Others, like hepatitis C, can be cured, although damage to the liver may result in elevated lipid levels even after treatment.

Medication-induced hyperlipidemia can often be eliminated by stopping or lowering the dose of the causative drug.

Diet and Lifestyle Modifications

The first step in managing hyperlipidemia is modifying the lifestyle factors that contribute to abnormally high blood fats—diet, lack of exercise, smoking, and the overuse of alcohol.

Among the lifestyle interventions a healthcare provider may recommend:

• Diet: Reduce intake of saturated fats to less than 6% of total daily calories. Replace saturated fats with healthier polyunsaturated or monosaturated fats. Increase intake of fruit and vegetables, whole grains, low-fat dairy, and oily fish rich in omega-3 fatty acids.
• Weight loss: Weight loss is currently recommended for obese people with a body mass index (BMI) over 30 and overweight people with a BMI between 25 and 29.9 who have at least two risk factors for cardiovascular disease (such as smoking, high blood pressure, family history, or diabetes).
• Exercise: The general consensus is that at least 30 minutes of moderate-intensity exercise should be performed three to four times per week.
• Smoking: Kicking this habit is possibly the single most significant lifestyle change a person can make to reduce the risk of cardiovascular disease. Stop smoking aids like nicotine replacement therapies and bupropion can significantly improve the chances of quitting.
• Alcohol: The American Heart Association recommends limiting alcohol intake to no more than two drinks per day for men and one drink per day for women.

Medications

There are a variety of medications that your healthcare provider may recommend if your cholesterol and triglyceride levels are not controlled by lifestyle changes.

Among them:

• Statin drugs are a class of medications that lower LDL levels by reducing the amount of cholesterol produced by the liver.
• Ezetimibe (cholesterol absorption inhibitors)
  
• Bile acid sequestrants are used to clear bile from the body and, by doing so, force the liver to produce more bile and less cholesterol.
• PCSK9 inhibitors
• Adenosine triphosphate-citrate lyase (ACL) inhibitors
• Fibrates are primarily used to reduce triglyceride levels and increase HDL levels.
• Niacin (nicotinic acid) is a prescription form of this B vitamin that may help reduce LDL and increase HDL (although it has not proven to be any more effective in doing so if combined with statins).

A Word From Verywell

Even though secondary hyperlipidemia is something you acquire, it shouldn't suggest that you are "to blame" for your condition. Some of the causes are beyond your control and some lifestyle factors might not have caused lipid elevations for you until recently.

Work with your healthcare provider to find the best ways to treat your condition. If your hyperlipidemia is especially resistant to treatment, you might need a referral to a lipidologist.