Small, dense LDL cholesterol and apolipoprotein B: relationship with serum lipids and LDL size.

OBJECTIVE

Small, dense low-density lipoprotein-cholesterol (sdLDL-C) is a recently recognised marker of cardiovascular disease risk. On the other hand, the usefulness of sdLDL-apoB concentration determination in clinical practice offers grounds for further exploration. This study investigates the associations of sdLDL-C and sdLDL-apoB with serum lipid parameters and LDL size in healthy men and women.

METHODS

The concentrations of sdLDL-C and sdLDL-apoB were measured after heparin-magnesium precipitation of serum samples from ninety-five asymptomatic subjects (47 men, 30 premenopausal and 18 menopausal women). LDL size was determined by gradient gel electrophoresis and serum lipid and lipoprotein parameters were measured by routine laboratory methods.

RESULTS

Compared to premenopausal women, men had higher sdLDL-C (P<0.001) and sdLDL-apoB concentrations (P<0.001). No difference in the sdLDL-C concentration was found between men and menopausal women. Menopause status was associated with higher concentrations of both sdLDL-C (P<0.01) and sdLDL-apoB (P<0.05). Subjects with the LDL B phenotype had elevated sdLDL-C (P<0.01) and sdLDL-apoB concentrations (P<0.001). LDL size and triglycerides were independent determinants of both sdLDL-C and sdLDL-apoB concentrations.

CONCLUSION

Gender and menopausal status have significant impact on sdLDL-C and sdLDL-apoB concentrations. The variability in sdLDL-C and sdLDL-apoB levels is considerably influenced by changes in LDL size and triglyceride concentration. Our results suggest that the characterisation of sdLDL particles by evaluating sdLDL-C could be complemented with sdLDL-apoB determination.