Abstract TP41: Racial Differences in Cumulative Blood Pressure Exposure and Hippocampal Subvolumes

Abstract

Introduction: We previously showed that a higher cumulative systolic blood pressure (cSBP) burden from young adulthood to midlife was associated with lower hippocampal volumes in Black but not White individuals independent of other vascular risk factors (VRF). And this difference was particularly evident in those with highest cSBP. In this study, we further explored these relationships by examining the impact of cSBP exposure on different hippocampal subvolumes. Methods: Thirty-four participants (18 black, 16 white) in the highest quartile of cSBP and longitudinal VRF exposure over 30 years with available brain MRI at the year 30 visit of the Coronary Artery Risk Development in Young Adults (CARDIA) cohort were used for this analysis. We measured the hippocampal subvolumes (CA1, CA2/3, and CA4) standardized as a percentage of total intracranial volume. T1 MRI images were processed using FreeSurfer (7.3.2) recon-all and the hippocampal sub-regions were segmented based on the computational atlas available in FreeSurfer. Results: Among the three regions, cSBP was only associated with CA1 subvolume in Black but not White participants. Racial differences were most evident in the CA1 hippocampal subvolume (p=0.099) and this difference remained even when other VRF were accounted for. Conclusion: Blacks with higher cSBP exposure over young adulthood to midlife, have smaller hippocampal CA1 subvolumes, which parallels the disparities in cSBP we previously reported. Our findings further highlight the anatomic vulnerability of the CA1 region to cSBP exposure and underscore the importance of early blood pressure control, particularly in minority populations where early screening for VRF may be limited.