Collection of Dried Blood Spots in the Survey of Health, Ageing and Retirement in Europe (SHARE): From implementation to blood-marker analyses.

SHARE, the “Survey of Health, Ageing and Retirement in Europe”, is a population-based socio-economic survey among people aged 50 and over with data from 28 European countries and Israel. It investigates individual, economic, health-related, and social impacts of the aging process in order to give answers to the challenges of population aging for individuals and society as a whole. Understanding aging per se and how we age differently given our individual background, current health and socio-economic factors is the aim of SHARE.
In order to maintain intertemporal, international and intercultural comparability, SHARE has adopted objective data collection in the health domain. SHARE measures physical performance, such as grip strength, peak expiratory flow, walking speed, chair stand and word recall and Euro-D depression among others in the cognitive and mental health modules. In 2015, SHARE has collected dried blood spot (DBS) samples as an additional objective measure of health. Eleven European countries and Israel participated in the DBS collection. The collection was harmonized in terms of designing documents, gaining consent, procuring blood-collection material, and training interviewers how to collect DBS samples while ethic and administrative regulations in all countries had to be observed in addition. Overall, about 27,200 respondents consented; the overall participation reached 72% with considerable differences between countries and interviewers.
This report describes the carefully monitored processes of consent-gaining for, and the implementation, collection and evaluation of the largest DBS sampling from a representative adult population in Europe, now awaiting the completion of blood-marker analyses. We also motivate the choice of blood markers and first assays.