Medically Reviewed and Written By: Kathleen O’Shea Northrup, MD
Lowering your cholesterol is a well-known way to decrease your risk of heart attack or stroke. You’ve likely heard of “good” cholesterol (HDL) and “bad” cholesterol (LDL), but what about Lipoprotein(a)? Lp(a), as it is more commonly known, has been the subject of increasing research in recent years, and the role it plays in cardiovascular disease might surprise you. By the end of this blog post, you will better understand whether getting tested for Lp(a) could make a difference in your health or the health of a loved one. But let’s start at the beginning.
First, what is cholesterol?
Cholesterol is a waxy, fat-like substance that is found in almost every cell of your body. Though we think of cholesterol as dangerous, it is actually necessary for good health. The body needs it to make hormones and help digest fatty foods.
Where does it come from?
Your body gets all of the cholesterol it needs from your liver, where it is produced. The problem is, many foods that we eat also contain cholesterol and our body simply doesn’t need all of the extra cholesterol we consume. Meats, shrimp, egg yolks, and cheese are common sources of dietary cholesterol. In addition, those foods contain fat- which causes your liver to make even more cholesterol. Some tropical oils (coconut oil, palm kernel oil, and palm oil) can also do this. These oils are commonly found in baked goods.
What does cholesterol do?
Your body needs some cholesterol to make hormones and help it to digest foods. However, too much cholesterol- especially “bad” cholesterol or LDL- can cause fatty deposits to build up in your blood vessels. These buildups make it harder for blood to flow through the blood vessels, and sometimes they can even break off and block a blood vessel. This can lead to a heart attack or stroke.
What are LDL, HDL, and non-HDL cholesterol?
When your doctor wants to check your cholesterol, they will typically order a “lipid profile,” which includes total cholesterol level, HDL, LDL, and triglycerides. It may also include a measurement of non-HDL cholesterol.
- Total cholesterol: this is the total amount of cholesterol in your blood
- LDL (low-density lipoprotein): LDL is a type of lipoprotein- a combination of fat (lipid) and protein that carries cholesterol around the body. This is also known as “bad” cholesterol. What makes LDL so bad? LDL causes a buildup of plaque on the walls of arteries. This is known as atherosclerosis, which causes arteries to narrow. Narrow arteries are harder for blood to travel through, and blood clots or pieces of plaque can break off and block them, leading to heart attack or stroke.
- HDL (High-density lipoprotein): HDL is also a type of lipoprotein. This is also known as “good” cholesterol because it carries LDL from other parts of your body back to your liver, where it can be removed from your body.
- Non-HDL: There are also smaller amounts of other lipoproteins in your blood that act in similar ways to LDL. This measurement includes those other “non-HDL” cholesterol.
- Triglycerides: While triglycerides aren’t the same as cholesterol, they are frequently measured simultaneously. They are a type of fat found in the blood. They come from the food you eat and can also be made by the liver. High levels of triglycerides can increase the risk of heart disease. Some people have high triglycerides due to genetic conditions, which put them at higher-than-average risk of cardiovascular diseases.
So, what is LP(a)?
LP (a) stands for lipoprotein (a), which also carries cholesterol in the blood. It is quite similar to LDL cholesterol, except it is even “stickier.” It is made up of a lipoprotein very similar to LDL, plus two other proteins known as ApoB and Apo(a). ApoB can cause atherosclerosis and plaque buildup, but Apo(a) works differently- when added to a lipoprotein, it is like coating it with a fine layer of honey. This makes it stick to artery walls and cause plaque buildup, much like LDL does- only more effectively. It is also thought to increase the risk of forming blood clots. If your level of Lp(a) is elevated, you have a two to four times higher risk of a major cardiovascular event than someone with low Lp(a) levels. That means a two to four times higher risk of heart attack, stroke, or limb ischemia (a problem with blood flow to your arms or legs). There is also a higher risk of developing aortic stenosis, which is a buildup of calcium on one of your heart valves that can make it harder for blood to leave your heart.
Unlike LDL, however, LP(a) is not affected by what you eat. It is made by the liver. The amount of LP(a) your liver makes is not something you can control- it is almost completely determined by your genes. Lp(a) levels are 70-90% genetically determined. For the most part, the level of Lp(a) in your blood will be the same when you are 5 years old as it is when you are 50. There are a few conditions that can slightly impact this, such as kidney disease, liver disease, thyroid issues, and menopause, but overall your Lp(a) level generally remains the same during your lifetime. One in five people worldwide has elevated Lp(a) levels and may not even know it. The risk is higher in people of African and South Asian descent.
At this time, there are no commonly used treatments for an elevated Lp(a) level. However, there are currently several promising treatments under investigation, so getting tested now might help you have important discussions with your doctor about these treatments in the future. The current advice is that an elevated Lp(a) level should be viewed as another risk factor for cardiovascular disease. If your Lp(a) level is elevated, it is especially important for you to work with your doctor to lower the risks of cardiovascular disease that you can control. These include exercising regularly, eating a healthy diet, controlling weight, and not smoking. Your doctor may also recommend a daily baby aspirin.
If your LDL level is also high, taking a cholesterol-lowering medication known as a statin is important. There have been some studies that show that statins can slightly increase Lp(a) levels, but they are still recommended due to their overall effects in lowering the risk of heart attack and stroke. In rare cases, your doctor may recommend you undergo a weekly procedure known as lipoprotein apheresis (which is a way to filter your blood through a machine to remove lipoprotein particles). Apheresis is only approved by the FDA for patients with a condition known as Familial Hypercholesterolemia, however. There are also injectable medicines known as PCSK9 inhibitors that can decrease Lp(a) levels by approximately 30%, but these are not routinely used. Luckily, there are several clinical trials currently underway for medications that could be used to lower Lp(a) levels by targeting the genes in the body that produce Lp(a). Given what we now know about the risks of elevated Lp(a), additional options for treatment could make a big difference in improving cardiovascular health.
If understanding all the different cholesterol types has your head spinning, there are ways you can start managing your health. Check out patientslikeme.com/groups/healthy_living/overview to join our discussion. You can share what you are going through, ask for advice, and plan a path forward from people who understand.