Lipoprotein(a) and incident ischemic stroke - The atherosclerosis risk in communities (ARIC) study

Background and Purpose - Numerous case-control and cross-sectional studies have reported higher median lipoprotein( a) [ Lp( a)] levels among stroke patients than controls, but existing prospective studies have not consistently shown an association. We sought to examine the relationship between plasma Lp( a) levels and the incidence of ischemic stroke among blacks and whites. Methods - Between 1987 and 1989, 14 221 men and women ( 3647 blacks and 10 574 whites) aged 45 to 64 years and free of clinical cardiovascular disease, took part in the first examination of the Atherosclerosis Risk in Communities ( ARIC) study cohort. Lp( a) and other risk factors for cardiovascular disease were measured at baseline. Results - During the 13.5-year follow-up, 496 ischemic strokes occurred. Participants with Lp( a) >= 300 mu g/mL had a 79% higher age, sex, and race-adjusted rate ratio ( RR) of ischemic stroke than did those with Lp( a) levels < 100 mu g/mL. Compared with Lp( a) < 100 mu g/mL, the multivariate adjusted RRs for Lp( a) >= 300 mu g/mL were 1.84 ( 95% CI, 1.05 to 3.07) in black women, 1.72 ( 95% CI, 0.86 to 3.48) in black men, 2.42 ( 95% CI, 1.30 to 4.53) in white women, and 1.18 ( 95% CI, 0.47 to 2.90) in white men. There was no significant increment in the RRs for 100 to 199 mu g/mL and 200 to 299 mu g/mL groups. Conclusions - A high Lp( a) concentration is associated with a higher incidence of ischemic stroke in blacks and white women, but not in white men.