PROJECT ABSTRACT
With an increasing proportion of the population at older ages (i.e., the `graying of America'), there is a growing
prevalence of Alzheimer's Disease and Related Dementias (ADRDs). The increase in proportion of older
Americans is happening at a faster rate among minority populations compared with non-Hispanic Whites
(NHWs), for instance, the number of “oldest” Americans is expected to grow by 81% among non-Hispanic Whites
compared to 131% growth among Non-Hispanic Blacks (NHBs) and 328% among Hispanics, by the year 2030.
Paralleling this increased racial disparity in the proportion of oldest Americans, is also a racial disparity in the
incidence and prevalence of ADRDs. For instance, there is significantly higher prevalence of all dementias
among NHBs compared to NHWs, with NHB men and women having a 2 – 2.5 times the prevalence among
NHW men or women. Among NHB men, the prevalence of Alzheimer's dementia (AD) is 2.5 times that among
NHW men. When only vascular cognitive impairment and dementia (VCID) is examined, NHBs were more than
twice as likely to develop VCID even after adjusting for differences in cumulative incidence of stroke, stroke
severity and known vascular and dementia risk factors. Suggesting the need to identify other factors that could
be contributing to the observed racial or black-white disparity. Our overall goals are to (1) determine whether
there is a black-white disparity in the prevalence of magnetic resonance imaging (MRI) defined markers of CSVD
among participants in the REGARDS cohort with confirmed stroke/TIA and (2) identify the contributions of CSVD
and ADRD genetic and vascular risk factors to the black-white disparity in VCIDs) and ADRDs. We hypothesize
that among REGARDS participants who had a stroke or TIA, the black-white disparity in the prevalence and
trajectory of VCI and ADRDs is partly due to black-white disparity in the prevalence and burden of CSVD, which
could be related to differences in the distribution of vascular and ADRD genetic risk factors. CSVDs are MRI
detected brain lesions whose components are cerebral microbleeds (CMBs), white matter hyperintensity (WMH)
lesions, lacunes and enlarged perivascular spaces (ePVS) and are associated with vascular risk factors as well
as incidence and prevalence of cognitive impairment and dementia. Our hypothesis will be tested based on the
following aims: (1) Determine the prevalence, pattern and racial/geographic difference in CSVD and variation in
brain volumetric parameters. (2) Examine the association between vascular and genetic (APOE ε4, ABCA7 and
TREM2) risk factors, and prevalence or disparity in CSVD and brain volumes. (3) Determine the association
between CSVD, brain volumetric measures and incidence, prevalence and trajectory as well as any observed
black-white disparity in risk of cognitive impairment and dementia. Completing the above aims will enable us to
identify a high-risk population for more targeted VCID prevention or treatment strategies to potentially reduce
black-white disparity in VCID. Additionally, the MRI scans retrieved, and the phenotype derived will be a useful
resource for further research in REGARDS.
