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Cardiovascular · 5 min

Lipids and the ApoB problem

Atherosclerosis is the leading cause of death worldwide, and it is, mechanistically, a disease of particles. Specifically, apolipoprotein B-containing particles — LDL, VLDL, IDL, chylomicron remnants, and Lp(a) — depositing cholesterol into the arterial wall over decades. Each of those particles carries exactly one ApoB molecule. Counting ApoB therefore counts the offenders directly.

Why LDL-C alone is not enough

Standard lipid panels report LDL-cholesterol, the mass of cholesterol carried inside LDL particles. But two people with identical LDL-C can carry very different numbers of particles — and it is the particles, not the cholesterol mass, that drive disease. This is why people with metabolic syndrome often have 'normal' LDL-C and a high ApoB. Their risk is hidden in plain sight.

Mendelian randomisation studies — natural genetic experiments — show that ApoB is the dominant causal driver of cardiovascular disease, with triglyceride-rich particles independently contributing risk on top of LDL.

Earlier and lower wins

Atherosclerosis is a function of cumulative ApoB exposure × time. A person with an ApoB of 80 mg/dL from age 20 accumulates far less arterial plaque than someone with the same number starting at 50. This is why waiting until your first event is the wrong strategy. Lifetime exposure is the variable.

Suggested targets, depending on overall risk: <80 mg/dL for low-risk primary prevention, <60 mg/dL for high-risk primary prevention, and <50 mg/dL for established disease. These are tighter than many physicians still use.

Lp(a): the one-time test almost nobody runs

Roughly 1 in 5 people inherit high lipoprotein(a), a particularly atherogenic, thrombogenic ApoB-containing particle. It is genetically determined, lifelong, and largely unaffected by diet or statins. Everyone should have it measured once. If it is elevated, the rest of your modifiable risk — particularly ApoB and blood pressure — needs to be driven lower.

What to do this week

  • Ask for ApoB (not just LDL-C) and a one-time Lp(a) on your next blood draw.
  • If your ApoB is above 80 mg/dL, treat it as a signal to act, not a number to monitor passively.
  • Optimise the lifestyle levers first: sleep, Zone 2, resistance training, fibre, low refined-carb load.
  • If lifestyle alone is not enough, discuss pharmacotherapy early — statins, ezetimibe, PCSK9 inhibitors, or bempedoic acid.