Apolipoprotein A-I and B Levels and the Risk of Ischemic Heart Disease During a Five-Year Follow-Up

This Québec Cardiovascular Study paper established apolipoprotein B as the single strongest metabolic predictor of ischemic heart disease risk — outperforming LDL cholesterol, the total/HDL cholesterol ratio, and triglycerides.

In 2,155 men followed prospectively over five years, elevated apoB carried a relative rate of 1.4 (95% CI 1.2–1.7) for IHD. This association held after adjustment for all conventional lipid variables, including LDL cholesterol and triglycerides. Stepwise regression selected apoB as the dominant metabolic predictor. ApoA-I showed an inverse association that lost statistical significance in multivariate analysis.

The clinical implication was clear at publication and has only strengthened with subsequent evidence: LDL cholesterol is a surrogate for the true atherogenic driver — the number of apoB-containing particles. When apoB is elevated and LDL appears normal (as in insulin resistance, metabolic syndrome, or diabetic dyslipidemia), the standard lipid panel provides false reassurance. The patient’s actual risk is higher than the LDL suggests.

We rate the evidence strong. A landmark prospective study from a high-quality cohort that remains a foundational citation for why apoB should be measured alongside or instead of LDL cholesterol in clinical risk assessment.