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Harmonized Cognitive Assessment Protocol Project

HCAP, the application of the Harmonized Cognitive Assessment Protocol to the SHARE data, is a project funded by the US National Institute on Aging (NIA) under the grant R01AG056329. The official project title is “Bio-medical and socio-economic precursors of cognitive decline in SHARE”. It is led by Axel Börsch-Supan (Principal Investigator) and Salima Douhou (Project Leader).


The expected increase in the prevalence of dementia in ageing populations is a major concern both from a health and an economic point of view. Dementia is currently without actual cure but symptom progression may be delayed if risk factors for cognitive impairment are diagnosed and treated at an early stage. The general aim of this and related projects is to exploit the international variation of health and life circumstances in order to identify which interactions of health and socio-economic conditions over the life course affect cognition in later life. The understanding of such life-course pathways to first mild cognitive impairment and then, possibly, dementia, should help in developing preventive early interventions. The study of older adults in a diverse array of countries will provide valuable information on cognitive status and relate it to the socio-economic and social environment of the elderly as well as biomarkers that may serve as instruments to target early prevention measures. It will enhance our understanding how the vastly differing social, health and long-term care systems affect mental health and resulting mortality of the aging populations. This holds especially for the life circumstances in Europe since World War II, which are likely to have influenced cognitive decline now at older ages. Moreover, the large variation in key policy variables, e.g. retirement age, identifies pathways from early retirement through inactivity and loss of social contacts to lower cognition, mediated by education, working environment and other socio-economic factors over the life-course.


The project will leverage the EU-funding of the Survey of Health, Aging and Retirement in Europe (SHARE) and the harmonization efforts with the US Health and Retirement Study (HRS) and the English Longitudinal Study of Ageing (ELSA) funded by NIA in earlier waves. SHARE is a large population-representative panel in currently 28 Continental European countries. Strictly harmonized health variables include self-reported health, ADLs and IADLs, physical measurements such as grip strength, peak flow and chair stand, and a large battery of tests for cognition and mental health, including MMSE. Moreover, SHARE has collected dried blood spot samples (DBSS) from some 27,000 respondents in a subset of 13 countries. Some markers correlating with cognitive decline are currently in the process to be assayed in Denmark, including cytokines and blood-based proteins such as BDNF and APOE4. The collection of biomarkers is a crucial part of the international harmonization strategy aimed at minimizing the effects of different response styles to self-reported health questions across countries.

The project will fill a strategic gap in this harmonization effort as the measurement of cognition in SHARE lacks the in-depth measurement according to the Harmonized Cognitive Assessment Protocol (HCAP) that has been designed for the HRS-style aging surveys supported by NIA. Filling this gap will permit a more accurate identification of mild and severe cognitive impairment in SHARE and the identification of biological and socio-economic characteristics associated with cognitive decline in later life.

Specific Aims

The project has three specific aims:

  1. Administer HCAP in five SHARE countries (Czech Republic, Denmark, France, Germany, Italy, and Poland) in a randomly drawn stratified study sample of 2700 respondents following the same protocols and applying the same measures as HRS.
  2. Analyze the collected data to assess the cognitive status (normal, mild and severe cognitive impairment) in the study sample; extrapolate the cognitive status to the full SHARE sample using the cognition measures and other covariates; compute country-specific prevalence rates of mild and severe cognitive impairment; compare these with HRS and other countries in the HCAP studies; and exploit the international variation of the SHARE plus HCAP data in order to identify which interactions of biomedical and socioeconomic conditions over the life course affect cognition later in life.
  3. Create a user-friendly database, archive it and document all tasks and results of the project.

This project is synchronized with the long-run agenda of the SHARE panel, which has collected blood in wave 6, has administered a life-history module in Wave 7, featured an extended cognition module in Wave 8, and will administer HCAP in Wave 9.