A global approach to the epidemiology of cognitive ageing and dementia: Cohort Studies of Memory in International Consortium (COSMIC)

Abstract

AbstractCOSMIC (COhort Studies of Memory in International Consortium) is an international consortium of longitudinal studies of cognitive aging and dementia, currently comprising 57 cohorts from 39 countries across 6 continents, comprising 186,000 participants (49% White, 8% Black, 21% Asian, 20% Hispanic, 2% Other). COSMIC embraces the power of collaboration through horizontal partnerships, with pooled and coordinated analyses after rigorous harmonization to examine ethno‐geographic differences in risk/protective factors and biomarkers, harness data from under‐represented populations, and permit cross‐validation in a field notorious for non‐replicable results. Analyses thus far have demonstrated that the cross‐national variation in prevalence of MCI is lower than generally reported, with commonality of most risk factors. The effect sizes of risk factors do, however, vary in populations, with APOE*4 and diabetes being associated with greater rates of decline in Asian than White populations. High school education is a significant threshold for protection against cognitive decline in later life, especially in Black and Asian populations. Physical activity shows a dose‐dependent relationship with incident dementia, suggesting that older adults should do three to six hours of physical activity per week for maximum cognitive benefits. The range and depth of such findings continues to grow, as is the community of researchers in both high and low‐middle income countries. With its global reach, open sharing of data and diverse network of researchers, COSMIC is creating a truly global epidemiology of dementia that is needed to deal with the world‐wide inequity in research, and meet the ambitious goals of the 2017 World Health Assembly to address the global epidemic of dementia and the hopes of people at risk of dementia everywhere.