Cholesterol and Heart Health: The Hidden Benefits of the Apolipoprotein B Test
- devillamcn
- Jun 10
- 3 min read
When visiting a primary care doctor, most established patients will have their cholesterol levels checked as part of their annual health check-up. They are an important indicator of cardiovascular health and disease risk, often reflecting how fats are transported and contribute to the formation of plaque within blood vessels and clogged arteries. Cholesterol is carried in particles called lipoproteins, aiding in transport throughout the bloodstream. These lipoproteins are made of lipids (cholesterol and triglycerides) and proteins (called apolipoproteins) and comprise different types:
HDL (High density lipoprotein) - referred to as the “good cholesterol”, these lipoproteins will transport excess cholesterol from the tissues and arteries
LDL (Low density lipoprotein) - referred to as the “bad cholesterol”, these lipoproteins will transport cholesterol from the liver to the tissues
VLDL (Very low density lipoprotein) - mainly carries triglycerides, and can contribute to cholesterol transport
IDL (Intermediate density lipoprotein) - forms when VLDL loses triglycerides as it circulates in the bloodstream, and can be further processed into LDL
Over time, excess cholesterol carried by LDL, VLDL and IDL can deposit along the inner lining of the arteries and form a fatty deposit called a plaque. Plaques narrow and harden the arteries, reducing blood flow to vital organs such as the heart. These can lead to further complications such as coronary or peripheral artery disease, heart attack and stroke. Since high LDL cholesterol is attributed to 24% of cardiovascular disease-related deaths, it is important to measure and monitor their levels with simple clinical tests.
A lipid panel will measure the weight of these cholesterol particles in the patient’s blood in order to assess cardiovascular disease risk. However, cholesterol tests will not directly reveal the number of lipoprotein particles that carry different amounts of cholesterol, such as apolipoprotein B.
What is the Apolipoprotein B test?
Apolipoprotein B (apoB) is a type of structural protein found on the surface of lipoproteins, with a central role of attaching to and forming lipoprotein particles (mainly LDL, VLDL, and IDL) to aid in the transport of triglycerides and cholesterol. This protein allows the lipoproteins to be recognized and taken up in the cells of various tissues. All particles that contribute to the formation of atheromatous plaques - LDL, VLDL, and IDL, are more accurately reflected in the apoB test. By taking into account all of the “bad cholesterol particles”, an apoB test can give additional insight into cardiovascular disease risk.
Who can benefit from this test?
For the general population, a standard LDL cholesterol is an appropriate measurement of “bad cholesterol” since high levels of LDL cholesterol are related to high levels of apoB. However, researchers argue that this may not be the case for certain individuals. These include patients with obesity, insulin resistance (prediabetes or diabetes), and high triglycerides, as these conditions often reveal smaller LDL cholesterol particles that correlate with lower LDL levels on standard cholesterol tests.
Other important beneficiaries of apoB testing include:
Patients on statins or cholesterol-lowering therapy
Patients with a family history of cardiovascular disease
Patients that are “high risk” for developing cardiovascular disease, with normal LDL levels
How do I interpret the results of the test?
The levels of ApoB are classified into the following categories:
In healthy persons: < 90 mg/dL
Borderline high to moderately elevated: between 90 and 129 mg/dL
High risk for cardiovascular disease: > 130 mg/dL
If levels of apoB are greater than 130 mg/dL, primary care physicians can recommend lifestyle changes such as regular exercise (≥30 min a day), decreasing the amount of saturated fat in the diet while incorporating more fruits and vegetables, and smoking cessation. If values remain high, cholesterol-lowering therapies such as statins, PCSK9 drugs, ezetimibe, and bempedoic acid are particularly helpful in lowering cholesterol levels, especially when combined with a healthy diet and exercise.
References
Feingold KR. Introduction to Lipids and Lipoproteins. [Updated 2024 Jan 14]. In: Feingold KR, Adler RA, Ahmed SF, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK305896/
Soffer, D. E., Marston, N. A., Maki, K. C., Jacobson, T. A., Bittner, V. A., Peña, J. M., Thanassoulis, G., Martin, S. S., Kirkpatrick, C. F., Virani, S. S., Dixon, D. L., Ballantyne, C. M., & Remaley, A. T. (2024). Role of apolipoprotein B in the clinical management of cardiovascular risk in adults: An Expert Clinical Consensus from the National Lipid Association. Journal of clinical lipidology, 18(5), e647–e663. https://doi.org/10.1016/j.jacl.2024.08.013
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