IS LIPOPROTEIN(A) AN INDEPENDENT RISK FACTOR FOR ISCHEMIC-HEART-DISEASE IN MEN - THE QUEBEC CARDIOVASCULAR STUDY

Objectives. This study was undertaken to determine whether lipoprotein (a) [Lp(a)] is an independent risk factor for ischemic heart disease ( IHD) and to establish the relation of Lp(a) to the other lipid fractio ns. Background. Several, but not all, studies have shown that elevated Lp(a) concentrations may be associated with IHD; very few have been p rospective. Methods. A 5-year prospective follow-up study was conducte d in 2,156 French Canadian men 47 to 76 years old, without clinical ev idence of IHD. Lipid measurements obtained at baseline included total cholesterol, low density lipoprotein (LDL) cholesterol, high density l ipoprotein (HDL) cholesterol, apoprotein B and Lp(a). During the follo w-up period, there were 116 first IHD events (myocardial infarction, a ngina, death). Adjusted proportional hazards models were used to estim ate the relative risk for the different variables. The cohort was also classified according to Lp(a) levels and other lipid risk factor tert iles to evaluate the relation of elevated Lp(a) levels to these risk f actors. A cutoff value of 30 mg/dl was used for Lp(a). Risk ratios wer e calculated using the group with low Lp(a) levels and the first terti le of lipid measures as a reference. Results. Lp(a) was not an indepen dent risk factor for IHD but seemed to increase the deleterious effect s of mildly elevated LDL cholesterol and elevated total cholesterol an d apoprotein B levels and seemed to counteract the beneficial effects associated with elevated HDL cholesterol levels. Conclusions. In this cohort, Lp(a) was not an independent risk factor for IHD but appeared to increase the risk associated with other lipid risk factors. (C) 199 8 by the American College of Cardiology.