Health and Aging in Africa: Longitudinal Studies of an INDEPTH Community

Abstract The Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) study examines biological, social, and economic determinants of disease and their effects on functional, health and cognitive outcomes among an aging population in South Africa. The emergence of the COVID-19 pandemic has profoundly impacted South Africa over the last 9 months, leading to stringent government lockdowns and widespread community transmission of SARS-CoV-2. COVID-19 has been demonstrated to be of particular risk to older adults around the world, especially those with underlying conditions including dementia and cardiometabolic disease. Gathering data on COVID-19 and accounting for the impact of this important public health crisis on personal and population health will be essential to fulfill the aims of the HAALSI P01 parent grant. In particular, Project 1's aims focus on predictors and consequences of Alzheimer's disease and related dementias (ADRD), attempting to identify diseases and social conditions that increase risk for cognitive impairment and decline. By leveraging the depth of longitudinal data available on the HAALSI cohort, including data on social and economic conditions, biomarkers, cognitive function, chronic conditions including HIV/AIDS and cardiometabolic disease, and genetic risks, as well as a subsample with MRIs and in-depth dementia assessments, we have a unique opportunity for novel research on causal relationships between dementia and COVID-19. Our research will facilitate better understanding of who is at risk of COVID-19 and why, and what the longer-term impacts might be on cognitive health of the cohort. We have two specific analytic aims to support these goals: (1) To assess how cognitive and genetic factors related to ADRD influence risk for SARS-CoV-2 infection and COVID-19 severity; and (2) To evaluate biological and socioeconomic pathways through which the COVID-19 pandemic may influence cognitive function, cognitive change, and incident dementia. To fulfill these aims we will utilize our planned Wave 3 survey to capture cognitive outcomes, and supplement existing HAALSI data with (1) a telephone survey to capture individual experiences during the COVID-19 pandemic; and (2) serological assays to assess SARS-CoV-2 infection. The telephone survey instrument has been harmonized with HRS sister study COVID modules to allow for cross national comparisons on COVID-19 exposures, health behaviors, and social consequences. Venous blood for SARS-CoV-2 serological assays will be collected during the planned HAALSI Wave 3 fieldwork in 2021, using tried-and-tested practices already in place in the Agincourt, field setting, in South Africa. We expect that this project will provide insight into mechanisms through which dementia and APOE genotype leads to SARS-CoV-2 infection and severe illness, and insight into the biological and socioeconomic pathways through which the COVID-19 pandemic may influence cognitive function, cognitive change and incident dementia. Our data collection and analyses will contribute to a better understanding of how COVID-19 impacts vulnerable populations in South Africa, regionally and around the world.