Is ApoB a Better Predictor than LDL? | Dr. Alan Flanagan & Danny Lennon | The Proof Clips EP 231

Episode Overview

• The discussion explores the shift in focus from LDL cholesterol (LDL-C) to Apolipoprotein B (ApoB) as a more accurate predictor of cardiovascular disease risk.
• The experts explain the fundamental difference between measuring the cholesterol content within particles (LDL-C) and counting the number of atherogenic particles (ApoB).
• They delve into the concept of concordance and discordance, highlighting situations where LDL-C levels can be misleading and why ApoB provides a clearer picture of risk.
• The conversation touches on the practicalities of why ApoB is not yet a standard test in routine blood work, despite its recognized superiority.

Key Concepts

• LDL-C vs. ApoB: LDL-C measures the amount of cholesterol carried by LDL particles. In contrast, ApoB measures the actual number of atherogenic (plaque-causing) lipoprotein particles, as each one contains a single ApoB molecule.
• Atherogenic Lipoproteins: The discussion clarifies that ApoB is present on all lipoproteins that contribute to atherosclerosis, including LDL, VLDL, and IDL particles, but not on protective HDL particles.
• Particle Number as the Primary Driver: The central thesis is that the total number of atherogenic particles (measured by ApoB) is a more direct and reliable indicator of atherosclerosis risk than the amount of cholesterol these particles contain (measured by LDL-C).
• Concordance and Discordance: In many people, LDL-C and ApoB levels are concordant (both high or both low). However, in cases of discordance (e.g., normal LDL-C but high ApoB), the ApoB number more accurately reflects the cardiovascular risk. This discrepancy can lead to underestimation of risk if only LDL-C is measured.
• Non-HDL Cholesterol: This is presented as a useful and readily available marker that is superior to LDL-C. It is calculated by subtracting HDL from total cholesterol and serves as a good proxy for the total amount of atherogenic cholesterol in the blood.

Quotes

• At 00:06 - "And it seems like the conversation is starting to shift a little bit from LDL cholesterol to ApoB being potentially, at least in certain circumstances, a better predictor of cardiovascular disease." - The host introduces the main topic, highlighting the evolving understanding of cholesterol markers.
• At 01:55 - "So by measuring ApoB, it's giving us a good idea of the number of these different particles... that refinement in understanding risk over time has essentially highlighted that it's not necessarily the cholesterol content per se of those particles, but the overall number of those particles." - A guest explains that the number of atherogenic particles, not just their cholesterol content, is the key factor in determining risk.
• At 05:15 - "So it is recognized... the various, you know, the EAS have have recognized the importance of a direct measure of ApoB. Um, generally, it's specifically recognized in the situations of discordance." - A guest confirms that major health organizations acknowledge ApoB's importance, especially in cases where LDL-C and particle count are misaligned.

Takeaways

• To get the most accurate assessment of your cardiovascular risk from lipids, request an ApoB test in addition to a standard cholesterol panel.
• Do not be falsely reassured by a "normal" LDL-C level; if there is discordance and your ApoB or non-HDL cholesterol is high, your risk is still elevated.
• If an ApoB test is not accessible, use non-HDL cholesterol (Total Cholesterol minus HDL) as a better and more comprehensive risk indicator than LDL-C alone.