The CANDID initiative Leveraging Cognitive Ageing Dementia Data from Around the World

Abstract

A large-scale, global approach to brain health research is required to reduce the scale and impact of dementia worldwide. Interrogating multiple datasets from different countries facilitates the investigation of key research questions which cannot be addressed with a single dataset alone. Furthermore, the generation of harmonised data from different countries allows country-specific policies and initiatives to be compared and evaluated with respect to their impact on the population prevalence of dementia, quality of life and other outcomes. The aim of the CANDID initiative (Leveraging Cognitive Ageing Dementia Data from Around the World) is to ease access to, and usability of, a platform of global datasets within the Health and Retirement Study (HRS) family of longitudinal aging studies. The HRS, a longitudinal, population-based study of 20,000 adults aged 51+ in the United States, has been collecting a vast array of health, economic and social data since 1992. Many other countries have followed suit, developing longitudinal, population-based studies using the HRS template, using harmonised survey questions and methods. These studies from around the world contain rich data pertinent to cognitive aging and brain health, which can be leveraged to answer important research questions on dementia prevalence, risk factors and care worldwide, and to inform policy and prevention strategies. Description The present document aims to guide the reader on how to access and use the cognitive variables publicly available across twelve HRS-family studies: the China Health and Retirement Longitudinal Study (CHARLS), the Costa Rican Longevity and Healthy Aging Study (CRELES), the English Longitudinal Study of Ageing (ELSA), the Brazilian Longitudinal Study of Health, Ageing and Well Being (ELSI), the Health and Retirement Study (HRS-USA), the Japanese Study of Aging and Retirement (JSTAR), the Korean Longitudinal Study of Ageing (KLoSA), the Longitudinal Aging Study in India (LASI), the Mexican Health and Aging Study (MHAS), the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA), the Ageing and Retirement in Europe (SHARE) and The Irish Longitudinal Study on Ageing (TILDA). The guide first introduces the twelve studies. It then defines and describes the cognitive tests and variables available across studies and provides comparability guidelines for best practice use of the cognitive variables across studies and waves. The twelve HRS-family studies and the time period (2010-2017) described in this guide were selected to cover a maximum range of comparable cognitive variables. This guide also provides instructions on how to access the studies’ cognitive datasets via the Gateway to Global Aging Data website and/or via the respective studies websites. Links to relevant documentation and codebooks publicly available via the Gateway to Global Aging Data website and/or via the respective studies’ websites are also included.