What does your ApoB value tell you about your risk of cardiovascular disease?

ApoB is a better predictor of cardiovascular disease risk than the well-known LDL cholesterol. A systematic review of 15 studies involving more than 593,000 participants showed that ApoB was more accurate than LDL cholesterol in all 9 direct comparisons, and also outperformed non-HDL cholesterol in 7 of those 9 comparisons. In a large study of nearly 294,000 participants with eleven years of follow-up, even among people with identical LDL values, the ten-year risk was almost doubled for those with high versus low ApoB: 7.3% compared with 4.0%. What ApoB measures is the total number of harmful fat particles in your blood. Each of those particles carries exactly one ApoB protein, so the ApoB value directly reflects how many of those particles are circulating. Whether those particles are large or small does not matter: it is purely about the count.

A higher ApoB is associated with a considerably higher risk of a heart attack. Each standard deviation increase in ApoB was associated with a 33% greater chance of heart disease in an analysis of more than 207,000 people in the United Kingdom. And among Danish individuals whose ApoB was higher than their LDL value would suggest, the risk of a heart attack was up to 75% higher in women and 52% higher in men, compared with those with the lowest 'excess'. This shows that ApoB captures information that LDL cholesterol simply misses.

ApoB does not tell the whole story, however. Lp(a), a specific type of fat particle with pro-inflammatory properties, confers additional risk on top of what ApoB already indicates. A complete picture therefore requires both values. Remnant cholesterol, another type of lipid fraction, was also found in a study of nearly 17,500 people over an average of nearly 19 years to signal additional risk that ApoB does not fully capture.

In everyday clinical practice, ApoB is still rarely measured, partly because there are no clear target values in guidelines, unlike LDL cholesterol. If you want a sharper assessment of your cardiovascular disease risk, you can ask your doctor to measure ApoB and Lp(a) alongside LDL cholesterol.