SMALL, DENSE LOW-DENSITY-LIPOPROTEIN PARTICLES AS A PREDICTOR OF THE RISK OF ISCHEMIC-HEART-DISEASE IN MEN - PROSPECTIVE RESULTS FROM THE QUEBEC CARDIOVASCULAR STUDY

Background Case-control studies have reported that patients with ische mic heart disease (IHD) have a higher proportion of small, dense LDL p articles than do healthy control subjects. The extent to which the ris k attributed to small LDL particles may be independent of concomitant variations in plasma lipoprotein-lipid concentrations remains to be cl early determined, however, particularly through prospective studies. M ethods and Results Baseline characteristics were obtained in 2103 men initially free of IHD, among whom 114 developed IHD during a 5-year fo llow-up period. These 114 case patients were matched with healthy cont rol subjects for age, body mass index, smoking habits, and alcohol int ake. LDL peak particle diameter (PPD) was measured a posteriori in 103 case-control pairs by nondenaturing gradient gel electrophoresis of w hole plasma. Conditional logistic regression analysis of the case-cont rol status revealed that men in the first tertile of the control LDL-P PD distribution (LDL-PPD less than or equal to 25.64 nm) had a 3.6-fol d increase in the risk of MD (95% CI, 1.5 to 8.8) compared with those in the third tertile (LDL-PPD>26.05 nm). statistical adjustment for co ncomitant variations in LDL cholesterol, triglycerides, HDL cholestero l, and apolipoprotein B concentrations had virtually no impact on the relationship between small LDL particles and the risk of IHD. Conclusi ons These results represent the first prospective evidence suggesting that the presence of small, dense LDL particles may be associated with an increased risk of subsequently developing IHD in men. Results also suggest that the risk attributed to small LDL particles may be partly independent of the concomitant variation in plasma lipoprotein-lipid concentrations.