Apolipoprotein B: A Crucial Indicator for Heart Disease Risk

Low-density lipoprotein (LDL) cholesterol, often referred to as ‘bad’ cholesterol, is widely recognized as a significant risk factor for heart disease. Most individuals undergo annual screenings to assess their levels of this compound. However, emerging research suggests that apolipoprotein B (apoB) could serve as a more accurate marker for determining heart disease risk, despite it not being a part of routine blood tests.

Apolipoprotein B is a protein that binds to harmful fat particles within the blood. These particles, like LDL, are known contributors to heart disease. The significance of apoB lies in its presence on the surface of these detrimental lipoproteins. Unlike traditional LDL counting, each harmful particle contains one molecule of apoB, thus providing a comprehensive view of the total number of plaque-inducing compounds in the body.

Traditionally, medical professionals focus on LDL levels to gauge heart disease risk. Elevated LDL levels often prompt physicians to suggest lifestyle changes or medications to manage cholesterol. Typically, a blood lipid panel gives an overview of cholesterol levels, encompassing LDL, very low-density lipoprotein (VLDL), and high-density lipoprotein (HDL). It also measures triglycerides, another type of blood fat that can increase heart disease risk.

According to Dr. Ann Marie Navar from UT Southwestern Medical Center, LDL and VLDL have the potential to become embedded in arterial walls, leading to narrowing and subsequent heart disease. Cholesterol, unlike sugar, isn’t dissolved in blood. It’s enclosed within entities known as lipoproteins, according to Navar.

A common misconception is that a normal LDL level guarantees a low heart disease risk. This isn’t always the case due to a phenomenon known as discordance, where an individual may have normal LDL but elevated apoB. This condition is more likely in those who are overweight, have diabetes, or possess high triglyceride levels. Currently, the American Heart Association does not recommend routine apoB testing unless patients exhibit high triglycerides.

Dr. Navar advocates for universal apoB testing, including it in her routine patient evaluations. Similarly, Dr. Samia Mora suggests at least a one-time apoB test to ensure it aligns with LDL results.

How is apoB Tested?

Heart disease remains the leading cause of death among men and women in the United States. Dr. Thomas Dayspring, a cholesterol authority and fellow of the National Lipid Association, emphasizes that measuring arterial plaque elements is best achieved through the apoB test. Speaking on the ‘Proof with Simon Hill’ podcast, Dayspring indicated that apoB is the most essential metric for assessing cardiovascular risk.

The apoB test directly measures the number of harmful lipoproteins in the blood. While LDL cholesterol indicates the cholesterol amount carried, apoB specifies the quantity of LDL particles present, as noted by Dr. Mora. Dr. Jeffrey Berger from NYU Langone considers apoB a comprehensive tool to assess cholesterol burden and plaque formation.

Despite the importance of apoB, less than 1% of American adults have been tested for it, as per a 2024 study published in The American Journal of Preventive Cardiology. However, there has been a growing emphasis on apoB in both health influencer circles and the commercial testing market. Companies like Sweetgreen are advocating for its awareness alongside their health-oriented menus.

Dr. Michael Shapiro, a preventive cardiologist, recommends the use of apoB testing in specific treatment scenarios such as during lipid-lowering therapy with statins. Determining if a patient has achieved their targeted cholesterol levels can entail further verification via apoB testing. Insurance may cover the test, though it generally costs approximately $70 at labs.

While there’s no universal guideline for ideal apoB levels, values below 90 mg/dL are typically considered satisfactory, with some experts suggesting even lower targets to optimally prevent heart disease.

A notable concern is the lack of cholesterol screenings among the population. According to research from Johns Hopkins University, nearly 25% of eligible adults have not had their cholesterol evaluated in the past five years.

Dr. Akshay Syal, an internal medicine physician at UCLA Health and member of the NBC News Health Unit, contributes to the public awareness about the importance of such tests through various media channels.