Abstract TMP116: Higher Lipoprotein(a) is a Risk Factor for Cognitive Impairment in Black but Not White Americans: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort

Background: Increased lipoprotein (a) [Lp(a)] is a risk factor for heart disease, and levels vary greatly by race, with blacks having 2-4-fold higher levels than whites. Despite the large body of evidence relating Lp(a) to cardiovascular risk, there is less known on its relation to cognitive function. Hypotheses: Lp(a) is a risk factor for cognitive impairment, and the association will be greater for blacks than whites. Methods: REGARDS recruited 30,239 black and white U.S. men and women between 2003-7 and a cognitive battery was administered every 2 years. With 3.4 years mean follow up, baseline Lp(a) was measured in 495 cases of incident cognitive impairment and 587 controls. All were free of prebaseline cognitive impairment and stroke. The association of Lp(a) and cognitive impairment was analyzed with logistic regression. Results: With multivariable adjustment, among black individuals the OR of cognitive impairment per SD higher increment of Lp(a) was 1.39 (95% CI 1.05, 1.84). There was no association in whites (OR 1.03; 95% CI 0.87, 1.21); p interaction race*Lp(a) =0.03. With further stratification by sex, among blacks the association was greater in women (OR 1.52; 95% CI 1.02-2.26) than men (OR 0.95; 95% CI 0.51, 1.76); p interaction by sex*Lp(a) =0.33. Compared to those in the lowest quartile of Lp(a), the risk of cognitive impairment in black women with Lp(a) above the median was more than doubled (Table). Conclusions: Lp(a) might explain part of the racial disparity in cognitive dysfunction with aging, especially in women (though confirmation required). To understand this, study is needed of racial differences in apo(a) size, interaction with environmental factors, and/or production or catabolization rates.