COSMIC: Cohort Studies of Memory in an International Consortium

CHeBA Consortia - COSMIC
Cohort Studies of Memory in an International Consortium: An international consortium to combine data from population-based longitudinal cohorts studies to identify common risk factors for dementia and cognitive decline.


Ageing is intricately connected with cognitive decline, and there is an increasing proportion of life lived with cognitive impairment as the lifespan increases. If an impact is to be made on this disability burden, we must understand the risk and protective factors for cognitive decline, frailty and chronic disease associated with ageing. The best approach is to study this using population-based ageing cohorts. A large number of such studies are ongoing internationally, and have identified a diverse range of factors [1], but there is considerable inconsistency in the results produced [2] and the existing evidence needs further systematic examination. This also relates to the evidence for vascular risk factors as risk factors for Alzheimer’s Disease (AD). While many publications have previously argued for this, a recent review concluded that “at the present time, there is no consistent body of evidence to show that vascular risk factors increase AD pathology” [3].

Researchers of brain ageing from around the world come together in the COSMIC collaboration to determine what factors are common for cognitive decline and dementia in all human populations irrespective of race, ethnicity and socioeconomic development.

We argue that the way to deal with inconsistencies in the literature is to harmonise international studies so that data can be pooled and risk factors examined with greatly increased power. Accordingly, COSMIC (Cohort Studies of Memory in an International Consortium) has so far brought together 57 cohort studies of cognitive ageing from 39 countries across 6 continents, with a combined sample size of almost 186,000 individuals. The aim of the collaboration is to facilitate a better understanding of the determinants of cognitive ageing and neurocognitive disorders. This is being achieved by:

  1. Harmonising shared, non-identifiable data from cohort studies that longitudinally examine change in cognitive function and the development of dementia in older individuals (60+ years).
  2. Performing joint or mega-analyses using combined, harmonised data sets that yield collated results with enhanced statistical power, in addition to comparisons across diverse ethno-regional groups.

We believe COSMIC to be a unique endeavor, as other consortia with similar or related aims do not have the same level of international scope, or have a focus such as genomic epidemiology: CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) and ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis).

NIH Grant Helps Support COSMIC to Late 2028

In August 2023, Professor Perminder Sachdev, Co-Director of CHeBA and head of COSMIC, was awarded US$7.27 million over 5 years from the National Institute on Aging (NIA) of the National Institutes of Health (NIH), USA.  This is in addition to a previous grant of US$2,57 million granted by the NIH in September 2017. The grants awarded allow further work in identifying risk and protective factors and biomarkers of cognitive ageing and dementia.

Investigators on the current grant include Professor Louisa Jorm, director of the UNSW Centre for Big Data Research in Health and CHeBA Co-Director Professor Henry Brodaty, as well as leading researchers from the USA (Professors Mary Ganguli, Richard Lipton), France (Dr. Maeleen Guerchet), Peru (Professor Jaime Miranda), India (Dr. Murali Krishna), UK (Professor Sarah Bauermeister) & Sweden (Professor Henrik Zetterberg). 



Dr Darren Lipnicki:
Research Fellow, CHeBA (Centre for Healthy Brain Ageing), UNSW Medicine

Bridie Vaughan:
Project Officer, CHeBA (Centre for Healthy Brain Ageing), UNSW Medicine