Discordance between lipoprotein (a) and LDL-cholesterol levels in cardiovascular risk assessment in apparently healthy subjects.

Background And Aims: Lipoprotein(a) is a recognized independent cardiovascular risk factor and apolipoprotein B (apoB) level better reflects the risk than LDL-cholesterol. Despite this cardiovascular prediction mostly relies on traditional risk factors. We evaluated the association between Lp(a) and lipid biomarkers of cardiovascular risk in relation to age and sex in apparently healthy individuals.

Methods And Results: 422 presumably healthy subjects aged 19-84 were included. Lipid profile, Lp(a), apoB and small dense low-density lipoprotein cholesterol (sdLDL-C) were assayed. Subjects were divided at desirable cut-points of apoB and LDL-C. A group with elevated apoB (≥100 mg/dL) at low LDL-C (≤115 mg/dL) was appointed as high-risk and a group with low apoB but elevated LDL-C as low-risk. Significantly elevated triglycerides, TG/HDL-C and sdLDL-C were found in high risk group, but Lp(a) levels were comparable. TG/HDL-C was the best predictor of high risk with a very good diagnostic accuracy (AUC = 0.85), whereas Lp(a) had no discriminatory power. Women aged ≤40 with low LDL-C ≤ 100 mg/dL and elevated Lp(a) ≥ 40 mg/dL had higher levels of apoB and sdLDL-C (p = 0.002; p = 0.07) than those with Lp(a) < 40 mg/dL, which was not observed in men. In young females increase of LDL-C and apoB significantly raised the risk of elevated Lp(a).

Conclusions: Women younger than 40 with low LDL-C may be at increased cardiovascular risk associated with elevated Lp(a) and apolipoprotein B levels. Inclusion of Lp(a) and apoB in the routine lipid testing providing information on an individual level may improve the prediction of cardiovascular risk in primary prevention.