While we all know to be on the lookout for high cholesterol numbers, it’s not always so easy to interpret the results, especially since cholesterol serves an important role in our body. Cholesterol is a waxy, fat-like substance that is needed for the body to function — it’s found in every cell, and it’s necessary for making the cell membrane, hormones, vitamin D, and more. But excess cholesterol can also clog up in the blood vessels and harden the arteries, which increases your risk for cardiac events like heart attack and stroke.

A cholesterol test (also known as a lipid panel or lipoprotein profile) evaluates four types of fats in the blood: total cholesterol; low-density lipoprotein (LDL) cholesterol; high-density lipoprotein (HDL) cholesterol; and triglycerides.

“The ideal amount of cholesterol you have really depends on who you are, your genes, and your risk of heart disease — so interpreting cholesterol test results is more nuanced compared to other blood work,” says Dr. Corey Bradley, a cardiologist at NewYork-Presbyterian/Columbia University Irving Medical Center. “Because cholesterol numbers aren’t that simple, people may get mixed messages about what is normal or abnormal.”

So what do the different cholesterol numbers mean? And what do they say about heart health? To learn more about understanding cholesterol results, Health Matters spoke to Dr. Bradley.

How is cholesterol tested?

When we do a cholesterol test, we take blood and look at the cholesterol and triglycerides circulating in the bloodstream. Cholesterol in the blood is packaged in something we call a lipoprotein – “lipo” meaning lipid fat, and protein, which holds the fat together.

I just got my cholesterol numbers. What do these results mean?

In the standard lipid panel that we order at the annual physical, the results will be for both cholesterol and triglycerides.

The first cholesterol number that usually comes up on a lipid profile is total cholesterol, which is the total amount of cholesterol that is present in all the lipoproteins circulating around our bloodstream. We have cholesterol in the low-density lipoprotein (LDL) particles, we have cholesterol in the high-density lipoprotein (HDL) particles, and the total cholesterol number is the sum of all of that cholesterol. The level should be below 200 mg/dL.

What are LDL cholesterol and HDL cholesterol?

LDL and HDL are different types of lipoproteins:

• LDL cholesterol is the number we care about because it tells us the most about someone’s risk of heart disease. LDL particles can get into the wall of an artery and cause plaque, which can build up and clog the arteries.
  
  The ideal LDL cholesterol number is generally less than 100 mg/dL, however we adjust the goal based on the risk or presence of heart disease. For someone who has a medical condition like diabetes, the ideal LDL cholesterol should be less than 70 mg/dL. For someone who recently had a heart attack, we want to prevent any progression of heart disease, so we lower our goal even further to less than 55 mg/dL.
  
  A common misconception people have about LDL cholesterol is that you need high amounts of it for your body. Our bodies do need cholesterol, but that’s very different from when we’re talking about LDL cholesterol. You can have incredibly low LDL cholesterol and still be perfectly healthy and perfectly normal.
  
• HDL cholesterol has been thought of as “good cholesterol” because it’s involved in something called “reverse cholesterol transport.” HDL helps to bring cholesterol from the body back to the liver, where it is broken down. The ideal level for HDL is above 40 mg/dL for men and above 50 mg/dL for women.
  
  Many people think that having normal or elevated HDL cholesterol negates the risk of having high LDL cholesterol. But that’s not really how it works. You really need the full picture to be able to understand where someone’s risk lies.

What are triglycerides, and why do they matter?

Triglycerides are the primary way that our body stores fuel. We get them both from diet (particularly from fatty foods) and our body can also make them. Whenever we’re consuming more calories than we’re burning, our body is making and storing triglyceride in our body fat (or adipose tissue). High triglycerides are associated with an increased risk of heart disease and diabetes; the optimal level for triglycerides is less than 150 mg/dL.

What is ApoB, and why did my doctor order this test?

Apolipoprotein B (ApoB) is not included in the standard lipid profile yet, but it really is the best predictor of heart disease risk. I think everyone should have an ApoB screening at one point in their life.

ApoB is a protein found in LDL particles in the blood. Each LDL particle (the type most linked to plaque and heart disease) has exactly one ApoB on it, so measuring ApoB is essentially a way of counting how many LDL particles you have, and that will be the most accurate measurement of your heart disease risk.

An ApoB test can be especially helpful if you have a family history of heart disease, but your standard LDL cholesterol number doesn’t seem to match your risk, or if you have high triglycerides or diabetes.

When should I get a cholesterol test?

The American Heart Association recommends all adults ages 20 or older have their cholesterol checked every four to six years if their risk remains low. And if you have a family history of heart disease, diabetes or other risk factors, you may need to test at a younger age and more often.  

The earlier we can identify people with severely high LDL cholesterol (for example in their 20s or 30s) the better we are at preventing cardiovascular-related health risks. The name of the game with cholesterol numbers is “lower for longer.” You want your cholesterol numbers to be lower for the longest amount of time because cumulative exposure causes your risk.

How can I lower my cholesterol numbers?

About 75% to 85% of our LDL cholesterol is determined by genes.

Sometimes diet and exercise make a big difference, but in the average person, your cholesterol number may not budge that much. People get frustrated because they do all this hard work, but really genetics determine your LDL cholesterol, often regardless of what else you do. When I have patients who say they want to focus on lifestyle, I say, ‘OK, let’s do that, but you get six months, and depending on the results, we have to have a conversation about medications and other options.’

Taking cholesterol medication shouldn’t feel like a personal failure. I love explaining the genetic basis of cholesterol because it’s like a light bulb goes off. They feel like they understand so much more about their own lab tests and their family history.

What if I need medication for high cholesterol?

If you have high cholesterol and haven’t spoken to a doctor about medication, I’d encourage you to go and talk to them about all the options.

I’m a big advocate for statins, but statins are certainly not the only option. I also believe that non-statin therapies should be explored in patients when statins alone are not enough or cannot be tolerated. What I really care about is lowering your LDL — it’s not how we get there.

There is much more hope now compared to 10 years ago because we have many safe and effective medications to treat cholesterol and lower your risk for cardiovascular disease.