European birth cohorts: a consideration of what they have addressed so far.

BACKGROUND: Knowing the research issues addressed by other cohorts when setting up new cohorts allows researchers to avoid unnecessary duplication of efforts, while permitting collaborations, including data merging data, to better tackle knowledge gaps. This study describes the topics addressed by European birth cohorts, the interaction between these cohort interests and aims, and describes the scientific publications deriving from the cohorts. METHODS: A previous study found 66 pregnancy and 45 birth cohorts in Europe. In this study, between August and October 2020, the predominant key areas addressed by the 45 birth cohorts identified in the previous study were evaluated, as were the publications found in PubMed that were associated with the 45 cohorts. A network analysis was performed to show the connections between the 13 key areas identified. A focus on a topic in common between two areas was provided, describing the related publications. RESULTS: A total of 1512 references were found in PubMed (148 publications per cohort). Thirteen predominant key areas were identified, the most common of which was "Environmental" (addressed by 20 cohorts). The Environmental, Genes, and Lifestyle exposure areas were the prevalent topics characterizing the network figure. The Environmental area had the largest number of interactions with the other areas, while the Prematurity area (4 cohorts) the least. The focus provided on smoking led to the comparison of 35 publications from the Environmental group of cohorts and 22 from the Prematurity group, but their objectives did not overlap. CONCLUSIONS: The results of this descriptive study show that the environment is a priority research area for cohorts in Europe and that cohorts with different research areas may have study issues in common, but may approach them from different viewpoints. Birth cohorts have wide-ranging aims and it would be almost impossible, and undesirable, to have perfectly overlapping and comparable objectives, but joining efforts would permit maximum use of available resources.