Abstract P371: Race Disparities in the Contribution of Lipid Profiles to Ankle-Brachial Index: Lifecourse Evidence from the Bogalusa Heart Study

Abstract

Background: Ankle-brachial index (ABI) is a practical non-invasive estimation of the burden of atherosclerosis on the vascular system. Although cholesterol is known to affect ABI as part of the disease process, information is limited on the contribution of longitudinal measures of cholesterol on the decline of ABI over time. Hypothesis: Race (black-white)—specific differences exist in cumulative burden effects of cholesterol, measured from childhood to adulthood, on ABI decline in young adults. Methods: We examined 497 adult participants of the Bogalusa Heart Study (72.8% white, 43.1% men, age 32-51 years), who had at least 3 measurements of cardiovascular (CV) risk factors since childhood (average follow-up 33.5 years). ABI was obtained in two separate instances: baseline (2001-2002) and follow-up (2007-2010), and its change was computed as the mean difference, divided by the time (years), between the two instances. The long-term cumulative burden of each risk factor was calculated as the total area under the curve (AUCt). Measurements of cholesterol and other CV risk factors in childhood, adulthood and AUCt were standardized to z-scores prior to regression analyses. Results: ABI significantly decreased (1.09±0.09 vs 1.03±0.09, p<0.01) after a mean follow-up of 6.8 years. There were no significant differences in annual ABI decline between male and female (p=0.56) / black and white (p=0.18) participants. In multivariable linear regression analyses, after adjustment for sex, lipid-lowering medications, smoking status, body mass index, systolic blood pressure and baseline ABI, significant predictors of annual ABI decline in white participants were: childhood total cholesterol (TC) (β= -0.11, p<0.01), low-density lipoprotein cholesterol (LDL-C; β= -0.10; p<0.01), and non-high-density lipoprotein cholesterol (non-HDL-C; β= -0.10, p<0.01), as well as the AUCt of TC (β= -0.09; p=0.02) and non-HDL-C (β= -0.08, p=0.04). The AUCt of HDL-C was the only significant predictor in black participants (β= 0.16, p=0.04). Conclusions: These findings suggest that the impact of cholesterol levels on future adult ABI decline starts in childhood, and follows a cumulative detrimental pattern throughout the lifespan in a race-dependent fashion. Further, this information may aid in the development of strategies to improve prevention, diagnosis and treatment of vascular disease by race group