Latinos have up to a fourfold risk of Alzheimer's disease and related dementias (ADRD) compared to non- Hispanic whites. Further, ADRD onset occurs earlier in Latinos and is often accompanied by vascular risk factors. Consistent with the NIA Alzheimer's prevention Initiative, we will focus on two vascular risk factors never studied in Latino ADRD prevention studies: obstructive sleep apnea (OSA) and non-dipping of blood pressure (NDBP). Over the last decade, OSA has been shown to increase mortality, stroke and vascular disease (e.g. NDBP). OSA is also linked with a 26% increase in cognitive decline or ADRD. However, most studies are limited by the use of self-reported data, measured OSA at a single time point or studied older adults, which do not preclude the possibility of reverse causation. Our published data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL; N≈16,000 at Visit-1), shows that OSA is associated with worse cognitive function, especially in females<55 years. Of interest, OSA had strong associations with prevalent (OR 2.1) and incident hypertension (HR 1.5). In clinical studies, NDBP was more common than clinic hypertension and had stronger associations with stroke and cognition; yet there is no information in the high-risk Latino population. There is an imperative to examine whether OSA in midlife is causal to late life cognitive decline in Latinos, the largest U.S. minority group; findings of important