THE IMPORTANCE OF SERUM-LIPOPROTEIN (A) AS AN INDEPENDENT RISK FACTORFOR PREMATURE CORONARY-ARTERY DISEASE IN MIDDLE-AGED BLACK-AND-WHITE WOMEN FROM THE UNITED-STATES

Objective. To determine the association of serum levels of lipoprotein (a) (Lp(a)) with coronary artery disease (CAD) in relation to other r isk factor variables in black and white women. Design. Retrospective c ase-control study. Setting. Community of Bogalusa, Louisiana and Cardi ac Catherization Laboratory at the Medical Center of Louisiana, New Or leans, USA. Subjects. The study included 47 female cases (52% black; m ean +/- SD age: 50.8 +/- 6.3 years) with confirmed myocardial infarcti on (MI) or at least 75% blockage of one or more major epicardial coron ary arteries determined by angiography, and 55 controls (60% black; me an +/- SD age: 49.6 +/- 7.9 years) with no high grade obstructive lesi on (<50% blockage) and no history of CAD. Main outcome measures. Lipop rotein variables, homocysteine, body mass index and cigarette smoking. Results. In the whole group, mean values of Lp(a), total cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB) and very-low-density lipoprotein cholesterol (VLDL-C) were higher (P < 0.05-0.0001) and apoA-I was lower (P < 0.05) in cases than in control s. The multivariate logistic regression analysis showed elevated level s of Lp(a) (>500 mg L-1) and LDL-C (>3.36 mmol L-1) as strong independ ent risk factors, with odds ratios (with 95% confidence intervals) of 13.6 (4.00-46.30) and 4.64 (1.31-16.49), respectively. ApoA-I, with an odds ratio of 0.11 (0.02-0.64), was a protective factor only at high levels (>53.6 mu mol L-1). Between races, significant odds ratios were noted in the black women for Lp(a) (OR = 15.98; P < 0.01) and LDL-C ( OR = 7.69; P < 0.05) and in the white women for only Lp(a) (OR = 15.23 ; P < 0.01). Conclusions. Lp(a) is an important risk factor for CAD bo th in black and in white women.