Lipoprotein(a), or Lp(a), is a protein that transports cholesterol in the blood. High levels of Lp(a) in the blood can increase the likelihood of plaques or blood clots forming in the arteries.

As a result of this effect, Lp(a) can increase the risk of cardiovascular disease. Taking steps to control cholesterol levels can help reduce this risk.

A doctor can carry out a blood test to check a person’s Lp(a) levels if they suspect that they may be high.

In this article, we look at what determines Lp(a) levels, what different test results might mean, and what steps a person can take to reduce their risk of cardiovascular disease.

A close-up of a nurse wearing rubber gloves placing a band aid on a person's arm, after performing a test for lipoprotein(a).Share on Pinterest
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Lipoproteins are a type of protein that transports cholesterol, a fatty substance, in the blood.

There are two main types of lipoprotein: high-density lipoprotein (HDL) cholesterol, which people may refer to as good cholesterol, and low-density lipoprotein (LDL), or bad, cholesterol.

The body needs a certain amount of cholesterol to function well. Cholesterol plays various roles in the body and is necessary for the maintenance of cell structure and the production of steroid hormones. High levels of HDL cholesterol may even help decrease the risk of cardiovascular disease.

However, high levels of LDL cholesterol can cause atherosclerosis, which is a buildup of fatty deposits in the blood vessels that can increase the risk of cardiovascular disease.

Lp(a) is a risk factor for developing cardiovascular disease. Research shows that Lp(a) can cause LDL cholesterol to form plaques on blood vessel walls, leading to the narrowing or blocking of blood vessels and the hardening of arteries, which increases the risk of heart disease and stroke.

Also, apolipoprotein(a), a protein that makes up part of Lp(a), can prevent enzymes from dissolving blood clots, so it may increase the risk of clots forming in the arteries.

Genetic factors seem to determine whether people have high Lp(a) levels. However, there is some evidence that diet and lifestyle may also affect them. More studies are necessary to understand exactly how diet and lifestyle habits contribute to high Lp(a) levels.

Research suggests that about 20% of the world’s population have elevated Lp(a) levels.

An Lp(a) test is not a routine test. However, doctors may test a person’s Lp(a) levels if their family medical history is unknown or they have:

  • a family history of early cardiovascular disease
  • cardiovascular disease but only slightly raised cholesterol or lipid levels
  • an inherited higher risk of high cholesterol levels

The doctor will perform this test by taking a sample of blood from a vein in the individual’s arm.

It is not necessary to prepare for an Lp(a) test. However, if the doctor also plans on carrying out a lipid panel test, which checks for cholesterol and triglyceride levels in the blood, they may ask the person to fast for 9–12 hours beforehand and only drink water.

Healthcare professionals will advise a person on how to prepare for their blood test.

High Lp(a) levels may indicate an increased risk of cardiovascular disease. People can receive normal lipid panel test results and still have elevated Lp(a) levels.

Some health conditions may cause high Lp(a) levels. These include:

In some cases, low estrogen levels may cause Lp(a) levels to increase. A doctor may test people going through menopause to check for a risk of cardiovascular disease, although this is rare.

Low or undetected levels of Lp(a) do not cause any health problems.

According to the American College of Cardiology, guidelines vary regarding cutoff points for high Lp(a) levels. High Lp(a) level markers may also vary among individuals, depending on risk factors and additional health conditions.

Some experts suggest that high Lp(a) levels are those measuring 50 milligrams per deciliter (mg/dl) or higher, whereas other guidelines suggest a slightly lower threshold.

Some research indicates that a reduction of Lp(a) levels to below 50 mg/dl is desirable, although levels above 25–30 mg/dl may still increase the risk of cardiovascular disease.

For example, studies have shown that adults have an increased risk of heart attack and coronary heart disease if they have Lp(a) levels above 30 mg/dl. Furthermore, they may have an increased risk of ischemic stroke if they have Lp(a) levels above 50 mg/dl.

Healthcare professionals consider low or undetected Lp(a) levels to be healthy. Normal Lp(a) levels are under 30 mg/dl. Some people may even have undetectable levels of Lp(a).

A person can speak with their doctor to understand their test results. Some laboratories may use different ranges or measurements.

Genetic factors determine Lp(a) levels. As a result, it can be difficult to alter them, and there are currently no specific treatments to do so.

Medications that inhibit PCSK9 may reduce Lp(a) levels, but further research is necessary to confirm this effect before doctors can recommend drugs for this use.

Lipoprotein apheresis is a procedure similar to dialysis. A machine separates cholesterol from blood plasma and removes the Lp(a) and LDL cholesterol from the blood.

People will require weekly or biweekly procedures to keep removing the cholesterol from the blood.

A limited number of medical centers in the United States and Canada offer lipoprotein apheresis. Alternatively, people can ask their doctor about any clinical trials that are currently researching further treatments for lowering Lp(a).

As genetic factors largely determine Lp(a) levels, these are not likely to change throughout a person’s lifetime.

If menopause is a contributing factor, though, taking niacin and estrogen may slightly lower Lp(a) levels. However, more research is necessary to confirm whether these treatments are effective and whether they can also lower the risk of cardiovascular disease.

In the meantime, people can focus on reducing controllable risk factors for cardiovascular disease. Focusing on lowering LDL cholesterol levels may be particularly beneficial.

Dietary and lifestyle changes can reduce LDL cholesterol, which can help lower the risk of cardiovascular disease.

People can take steps to improve their health and lower their risk. These include:

  • Adopting a healthy diet to support the heart: A healthy diet includes omega-3 oils, nuts, olive oil and some other vegetable oils, whole grains, fruits, and vegetables. It should also exclude or limit saturated and trans fats, such as those in fatty meat, dairy, and processed foods.
  • Exercising regularly: Staying physically active can lower LDL cholesterol and raise HDL cholesterol.
  • Managing body weight: If people have excess weight, losing 3–5% of their body weight is enough to lower LDL and raise HDL cholesterol.
  • Minimizing stress: Chronic stress may increase LDL cholesterol.
  • Quitting smoking: People who smoke can seek help to stop smoking to support heart health.
  • Getting better quality sleep: The Centers for Disease Control and Prevention (CDC) recommend that people aim to get 7–9 hours of sleep each night to help the heart and blood vessels recover and repair.
  • Limiting alcohol: People can limit their alcohol intake to increase heart health. Anyone who needs help to stop drinking can seek support from medical and mental healthcare professionals and support groups.

Genetic factors primarily determine Lp(a) levels, so these generally remain the same throughout a person’s life. High levels of Lp(a) can increase the risk of cardiovascular disease.

Although there is currently no specific treatment to lower Lp(a) levels, taking steps to lower LDL cholesterol can help reduce the risk of cardiovascular disease.