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. COSMIC has so far brought together 37 cohort studies of cognitive ageing from 29 countries across 6 continents, with a combined sample size of over 115,000 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.

The IALSA research network contributed to the description of the COSMIC studies and variables included in this catalogue.





COSMIC website


Summary Statistics


Individual Studies

Harmonization Studies

Variables classifications