Cohort Studies: A Vital Tool for Understanding Child Development

C. PIRUS, C. BOIS,
M.-N. DUFOURG,
J.-L.. LANOË,
S. VANDENTORREN,
H. LERIDON, the ELFE TEAM

• Constructing a Cohort: Experience with the French Elfe Project

C. Pirus, H. Leridon

• Large Child Cohort Studies across the World

Given the multiple factors involved and their numerous interactions, research in the field of child development is particularly complex. The best way to observe children's trajectories is to conduct a cohort study. This involves selecting a sample of children at a very young age and tracking their development from birth to adulthood. A cohort study of this kind will be launched in France in 2011.

In a first article, Claudine PIRUS, Corinne BOIS, Marie-Noëlle DUFOURG, Jean-Louis LANOË, Stéphanie VANDENTORREN, Henri LERIDON and the ELFE TEAM present the organization and objectives of the French child cohort study, called Elfe (Étude longitudinale française depuis l'enfance) and detail their multidisciplinary approach. The Elfe project will be launched in March 2011, with the support of numerous research institutions in health and the social sciences. Based on a longitudinal life course approach, the project involves wide-ranging data collection operations - face-to-face and telephone interviews with parents, measurement of biological markers, installation of sensors to collect environmental data, gathering of contextual and administrative information - in many different areas, including health, family background, schooling, exposure to pollutants, etc. Two pilot studies have been conducted to validate the methodology for contacting the families in the French context of hospital maternity care, and for developing the questionnaires used in the first survey waves.

While the Elfe project is the first multidisciplinary child cohort study ever conducted in France, it is just one among many such projects taking place across the world. In the second article, Claudine PIRUS and Henri LERIDON describe the experience of other countries in this field, ranging from the pioneer cohort launched in the United Kingdom in 1946 (and still active today, although the "children" are now aged 65) to the numerous cohorts set up more recently elsewhere. The objectives and limitations of these cohorts are varied, as are the practical solutions adopted to recruit and monitor the children's progress through life. The difficulties encountered illustrate the challenges of initiating and maintaining ambitious long-term projects, and of keeping in touch with study participants over the years. Existing cohort studies have produced abundant findings on the ways in which family situation and financial status influence child health, psychomotor and intellectual development, and on the impact of childhood living conditions on adult behaviour. These findings vary over time and between countries, and the Elfe cohort will provide analyses of child development in France comparable to those of other countries.