Longitudinal MRI Measures of Cerebrovascular Injury and AD Atrophy in a Study of Latinos (SOL-INCA-MRI Long)

About This Grant

PROJECT SUMMARY/ABSTRACT Latinos constitute a heterogeneous population which accounted for slightly more than 50% of the United States (US) population growth for 2010 to 2020. Latinos are also becoming a larger proportion of older individuals in the US. Despite this, biomarker studies of normal aging and cognitive impairment remain limited, and the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) constitutes the only known representative sample. Moreover, epidemiological data indicate that Latinos have a higher prevalence of vascular risk factors, lower cardiovascular health metrics, and a greater likelihood of having mild cognitive impairment (MCI) or dementia due non-Alzheimer’s disease processes that differ by heritage. Consequently, diagnosis and treatment of Latino persons with cognitive impairment may be more challenging, but more amenable to prevention through reduction of vascular risk factors than non-Hispanic White persons where vascular risk and disease is less prevalent. The first cycle of “MRI Measures of Cerebrovascular Injury and Alzheimer’s disease Atrophy in a Study of Latinos (RF1 AG054548; AKA SOL-INCA-MRI)” was designed to identify biological underpinnings of normal cognitive aging, MCI and Alzheimer’s disease and related dementias (ADRD) in a representative subgroup of the HCHS/SOL 62 + 9 years of age on average. Despite restrictions imposed by the COVID pandemic, our investigators successfully obtained brain MRI from 2668 individuals or >95% of the proposed study cohort. From these data we have published on 1) differences in brain structure from ages 35-85; 2) the impact of vascular risk and sleep on brain structure; 4) the association of cognition with subsequent MRI measures; and 4) genetic influences on select brain measures. These early results, while of scientific value, are cross- sectional and do not reflect ongoing degeneration or incident vascular injury, limiting inferential power that might extend scientific knowledge of brain aging and ADRD in this unique cohort. For this application, we propose to extend our work to include longitudinal MRI analysis, leveraging longitudinal biomarker and clinical data from 3 visits, spanning approximately 12 years of HCHS/SOL and its cognitive ancillary study (SOL-INCA- AD; R01 AG075758, Gonzalez, DeCarli Co-PIs) on a deeply characterized and diverse Hispanic/Latino cohort. Adding longitudinal image analysis in combination with longitudinal lifestyle, medical risk factors, plasma ATN biomarkers, genetics and cognitive assessment in this Latino cohort will address multiple ADRD research milestones and priorities while enabling stronger statistical inference of risk and resilience factors amongst representative, yet relatively young-old members of diverse Latino communities, creating the opportunity to identify modifiable risk factors, potentially reducing societal burden due to later-life ADRD in this rapidly growing portion of the older US population.