03/08/2026
Two people on a statin can show the same normal LDL cholesterol and carry different cardiovascular risk, and the variable that separates them is not the amount of cholesterol in the blood but the number of particles carrying it.
Researchers drew on the Copenhagen General Population Study, took 13,015 adults who were already on statin therapy, measured both their LDL cholesterol and their apolipoprotein B, and followed them for a median of eight years of heart attacks and deaths. When the two markers disagreed, the people whose apoB ran high while their LDL cholesterol sat in the normal range had a 49% higher rate of myocardial infarction and a 21% higher rate of death from any cause than the people whose two markers were both low.
The finding that gives this study its weight is the mirror image. The intuitive assumption is that any elevated marker means elevated risk, so a high LDL cholesterol should be as dangerous as a high apoB. It was not. When LDL cholesterol ran high but apoB stayed normal, the risk did not rise at all, for either heart attack or death. Non-high-density-lipoprotein cholesterol, which sums the cholesterol across every atherogenic particle and so tracks the particle burden more closely than LDL cholesterol does, behaved the same way apoB did. The cholesterol concentration on its own carried no signal once the particle count was normal. It was the number of particles, not the amount of cholesterol they carried, that separated the people who had events from the people who did not.
The reason the two markers can diverge is that they measure different things. Every atherogenic particle, whether LDL, VLDL, IDL, or lipoprotein(a), carries exactly one apoB molecule, so apoB is a direct count of how many such particles are in circulation, while LDL cholesterol measures only the mass of cholesterol those particles happen to be carrying. The two readings split apart most in people whose particles are cholesterol poor, the small dense LDL common with high triglycerides and insulin resistance: each particle carries less cholesterol, so LDL cholesterol can fall into the normal range on a statin while the particle count stays high, because the cholesterol measure understates how many particles are actually there. It is the particles themselves, not their cholesterol cargo, that cross the arterial wall and initiate plaque, which is why a marker that counts them tracks disease more faithfully than one that weighs their contents.
This is an observational cohort, so discordant apoB cannot be declared a cause of the events it tracked; it may partly mark people whose metabolic health is worse in ways that independently raise risk, and no observational design fully removes that possibility. The population was specifically statin-treated, so the finding describes residual risk in people already on therapy and does not extend to untreated adults, in whom LDL cholesterol and apoB agree more often. Discordance was defined by a median split rather than a clinical threshold, which sorts people into high and low relative to this cohort rather than to any absolute cutoff. And the study measured association with events, not the effect of lowering apoB, which is a different question a cohort cannot answer.
What the evidence supports, is that in people on statin therapy, apoB and non-high-density-lipoprotein cholesterol reflect a residual cardiovascular risk that LDL cholesterol alone can miss, and that a normal LDL cholesterol does not rule that risk out when the particle count is still high. What it does not support is a promise that lowering apoB to a target will lower any individual's event rate, because demonstrating that requires a treatment trial rather than a cohort. The practical reframe is still worth stating: lipid management overwhelmingly targets the cholesterol number, the value printed on every standard panel, while the particle count that this study flags as the marker carrying the residual risk is one most people on a statin have never had measured. The open question is whether treating patients to an apoB target, rather than an LDL cholesterol target, changes hard cardiovascular outcomes, or whether apoB is simply the more honest readout of a risk that is already there.
Johannesen et al., J Am Coll Cardiol 2021
Sniderman et al., Circ Cardiovasc Qual Outcomes 2011
Marston et al., JAMA Cardiol 2022
