Researchers hold workshop on combining European birth cohort data to benefit child health research

On 29th and 30th March, a workshop was held at CREAL in Barcelona to discuss how data analysis can be optimised. The workshop was co-funded by EUCCONET, The European Child Cohorts Network and CHICOS (Dr. Martine Vrijheid, CREAL researcher, is the coordinator of CHICOS project), a European (FP7) project funded to develop a child cohort research strategy for Europe.

The meeting was attended mainly by European cohort researchers who are currently involved in pooling data across cohorts or who are planning to do so in the future. Topics for discussion had chosen based on the current stage of various available case studies, and their relevance to known and arising public health issues in children, and birth cohort research. This meeting will form the basis for a step-by-step guide to combined birth/child cohort analyses.

The objective of this meeting was to discuss past and current methodology, opportunities and benefits of data combination. “How to combine birth/child cohort data” will be the focus of a plenary session inviting speakers with experience in combining data as part of some of the above-mentioned EC projects. This was followed by parallel sessions on specific topics for which case studies are currently evaluating issues around data pooling. These will focus on:

• Fish consumption in pregnancy and fetal growth;

• Alcohol consumption during pregnancy and birth weight;

• Selected maternal occupations and fetal health;

• Social inequalities in preterm delivery;

• Prenatal environmental exposures (POPs) and birth outcomes.

A report containing the meeting minutes was produced shortly after the meeting, and contain provided an insight in the lessons learnt from past and current activities combining cohort data. Based on this, and in close collaboration with the CHICOS project, a step by step guide was developed by the end of 2012 with general recommendations for future combination birth cohort studies. The target audience of this guide will be cohort and child health researchers.

European birth and child cohort research has resulted in an extensive amount of data on child health outcomes and risk factors. Recommendations have been made to combine data from cohorts in order to increase statistical power when outcomes or exposure are rare, or when new study designs requiring large sample sizes are applied (e.g. in the field of genetics). Data exchanges have been initiated as part of replication and comparison studies in order to improve causal inference. European cohorts are now increasingly working together encouraged by coordinating networks (such as ENRIECO and CHICOS) and European research projects on widely diverging topics (e.g. ESCAPE, EAGLE, MEDALL).

Various European projects have over the last few years made major progress in overcoming research challenges and drawing meaningful conclusions from combined birth cohort studies. Other projects are just starting analyses now. This is therefore an ideal time to take stock of European cohort combination projects and draw lessons for the future.