ELSA-HCAP 2: Second Administration of the Harmonised Cognitive Assessment Protocol (HCAP) in the English Longitudinal Study of Ageing

University College London, London

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Abstract

Alzheimer’s disease and Alzheimer’s disease related dementias (AD/ADRD) impose a devastating burden on society and the quality of life of sufferers and their families, and present serious challenges to health and social care. Cross-national comparisons of older populations supply valuable information about the prevalence of mild cognitive impairment and AD/ADRD in different countries, and can provide insights into the impact of different risk factors, welfare regimes, and health and social care policies. In 2018, the Harmonized Cognitive Assessment Protocol (HCAP) was completed by 1,273 participants in the English Longitudinal Study of Ageing (ELSA) aged ≥65, selected on the basis of previous cognitive performance to include individuals with low, moderate and normal cognition. Informants were also assessed. The HCAP was identical to that administered in the Health and Retirement Study (HRS) in 2016, and the common language has allowed direct comparisons between the USA and England. This proposed follow-up study will administer the HCAP in 2023 to an expanded sample that will include all surviving participants in the original study (~1,000), plus a new sample including all ethnic minority participant in ELSA aged ≥65 years and randomly selected additional cohort members to bring the achieved sample to 2,000. We expect the protocol to be very similar to that used in the original study, including face-to- face assessments with participants and interviews with informants about changes in the person’s cognitive status. The readministration of the protocol to the original sample will permit assessment of trajectories of cognitive impairment and the incidence of AD/ADRD over a 5 year period, and facilitate comparisons with the changes over time observed in the HRS. The inclusion of the ethnic minority sample will add to the limited evidence of ethnic disparities in older age cognitive function in England. Analyses will focus on socioeconomic disparities in cognitive decline, and the progression of cognitive impairment to dementia. Extrapolation to the full ELSA cohort will facilitate modeling of social and economic impacts of AD/ADRD, and will provide a basis for analyses of the multifactorial determinants of cognitive decline over the 20+ years since the study started. The study will provide detailed information on the relationship between cognition and COVID-19 risk, and on socioeconomic and ethnic disparities in the impact of the pandemic on cognition. We will prepare a well- documented anonymized dataset for deposit with the UK Data Service that will be accessible to researchers and scholars throughout the world for further analysis. This application is being submitted by Andrew Steptoe (PI) and Paola Zaninotto (Co-I) from UCL and Carol Brayne (Co-I) from the University of Cambridge, with consultants from the HRS (David Weir, Kenneth Langa), the Gateway to Global Aging (Jinkook Lee) and the Cognitive Function and Ageing Study (Fiona Matthews).