The Effects of COVID-19 on the Well-being, Cognition and Mortality of Persons Living With Dementia - PROJECT SUMMARY Although the prevalence of Alzheimer’s disease and related dementias (ADRD) has been decreasing, the COVID-19 pandemic may have halted or reversed that trend. This project will quantify the effects of the pandemic and of attendant public health and social measures on the cognitive status, mortality, and well-being of persons living with ADRD and of the older population in general. Persons living with dementia were especially vulnerable to COVID-19 because many were living in nursing homes, and even those residing in the community were disproportionately vulnerable because of caregivers coming to their homes. Further, those initially not living with dementia may have experienced accelerated cognitive decline because of COVID-19 infections, as well as due to disruption of daily routines, social isolation and stress. Subpopulations by race, ethnicity and socioeconomic status were impacted unequally. This project has three specific aims. The first is to use a new and updated model of cognition to estimate trends in ADRD prevalence, incidence, and mortality prior to the pandemic. We will use data from the Health and Retirement Study (HRS), a large, nationally representative, longitudinal survey of the U.S. population over age 50. The HRS has a wide range of information on cognitive abilities, mortality, dementia risks, and physical and mental health, but only a subsample of the HRS from the Aging, Demographic, and Memory Study (ADAMS) has a clinical assessment of dementia. In prior research, we used ADAMS to develop a model of the probability of dementia to estimate the cognitive status of the entire HRS sample. In this work, we will expand this model to estimate dementia incidence and mortality as well, and incorporate recently released data from the Harmonized Cognitive Assessment Protocol, further increasing precision so as to permit the study of changes in ADRD resulting from the pandemic in subpopulations, such as race and ethnicity, marital status, and socioeconomic status. Second, we will document changes associated with the pandemic in mortality, well-being, use of formal and informal care, and other outcomes. We will incorporate variation in state policies to assess their effect on individual outcomes. We will compare these effects among those who were living with dementia prior to the pandemic to those whose cognitive function was normal. We will use innovative models and data from various HRS supplements focusing on COVID-19 to estimate these effects with precision. Third, we will estimate the incidence of dementia and dementia mortality after the pandemic through 2026 and find the extent to which COVID-19 altered pre-pandemic trends. We will assess whether ADRD incidence differed by individual characteristics, such as geographic location, race, socioeconomic status, and living arrangements. The developed cognition measures will be made publicly available to enhance future research.