The project delivered substantial scientific and technical progress across all planned work packages. Using harmonised data from 16 European birth cohorts within the EU Child Cohort Network, I conducted federated analyses to quantify socio‑economic inequalities in childhood respiratory tract infections. These analyses included descriptive exploration, regression modelling, and one‑stage and two‑stage individual‑participant data meta‑analytic models executed through the DataSHIELD platform. The results consistently showed socio‑economic gradients in both upper and lower respiratory tract infections across childhood, with notable heterogeneity across cohorts. This work generated a complete set of scientific findings.
The project also achieved its technological objective through the development of the dsMediation package, a DataSHIELD‑compatible tool enabling privacy‑preserving causal mediation analysis across distributed datasets. The package implements four methodological approaches (simulation, regression, weighting, and imputation) and includes bootstrap procedures for uncertainty estimation. It was extensively tested using synthetic and publicly available datasets to ensure accuracy, stability, and reproducibility. The package is fully functional and has already been adopted in multi‑cohort studies within the EU Child Cohort Network.
Building on these developments, the project advanced the analysis of early‑life risk factors as potential mediators of socio‑economic inequalities in childhood respiratory infections. I identified mediators available across cohorts, developed the analytical framework using Directed Acyclic Graphs, and conducted preliminary mediation analyses using the dsMediation package. These analyses confirmed the feasibility of the planned models and the suitability of the harmonised datasets for mediation analysis.
In parallel, the project delivered all planned scientific training and capacity‑building activities. I gained advanced expertise in mediation analysis, causal inference, and multi‑cohort epidemiology through specialised courses, hands‑on analytical work, and close collaboration with methodological experts during the secondment at the University of Turin. These activities strengthened the technical foundations required to complete the project’s scientific objectives and contributed to the successful development and application of the dsMediation package.