Workshop: Cohorts: coordinated tools for decision support

Abstract Longitudinal cohorts, by allowing to follow over the time a group of persons with common characteristics to identify the occurrence of health events, have proven to be very valuable instruments in medical and public health research. For instance, it is possible to investigate links between exposures (demographic, biological, behavioral, environmental, or genetic) and the occurrence of observed health events. And indeed the applications of the cohorts are multiple: besides public health research (links between risk factors or exposures and disease, health effects of unusual or still unknown exposures), it is possible, for example, to investigate the impact of a therapeutic strategy or complex healthcare intervention on the population status. Therefore, observations resulting from cohort studies are now often at the heart of public policy decision-making. In addition, health-data collections are increasingly broad in our societies (data from research, care, patient communities, or using personal initiatives such as smartphone applications and connected objects) and heterogeneous (genomic, physiological, biological, clinical, social and environmental). However, the efficiency of these epidemiological studies is limited by many factors, while resources required to develop them are very important. The lack of knowledge of the European landscape, the lack of harmonization of practices or governance or the lack of communication between various stakeholders, have an impact on the strategy to adopt. It would be essential to consider procedures to optimize resources, harmonize methodologies and coordination between structures, in such a context where epidemiological expertise is sometimes scarce and under-resourced. Furthermore, possibilities of international cross-cohorts linkages and collaborations could allow for unique and fruitful research opportunities, impossible to achieve in the setting of a stand-alone cohort. During this workshop, we propose to present different European initiatives and coordination models, but also to highlight collaborations between these cohorts. This brainstorming would allow us 1) to expose methodologies and best practices, which are developed by the various stakeholders; 2) to identify common or transposable procedures in order to participate in sustainable European strategy and at last, to address the challenges of developing future cohorts and using personal health data. For this purpose, four speakers will present the French landscape developed over the past ten years and three models of cohort coordination and data mining in Europe: the French cohort Constances, the Swedish consortium Cohorts.se and the German National Cohort. Each participant will speak for 15 minutes. Then the chairperson will lead the workshop’s joint discussion with the four speakers and the audience. Key messages cohorts are one of the reference instruments for epidemiological and public health research, and represent a significant advantage in decision support. efforts are need to improve the coordination of these cohorts, both nationally and internationally, to sustain these expensive instruments and foster the development of international collaborations.