Introduction

The increasing recognition that events during pregnancy and early infancy have a bearing on future health and disease through later life (Barker et al, 1993) has led to the development of longitudinal, epidemiological studies beginning in early life to study the antecedents of important public health outcomes. The case for such studies has been further enhanced by developments in human genetics stemming from the human genome project and leading to advances in both knowledge of genetic influences on human health and disease and technology that facilitates high throughput and cost-effective analysis of human DNA. The study that will be described in this chapter – the Avon Longitudinal Study of Parents and Children (ALSPAC; full details, including design, study protocols, response rates and publications are available at www.alspac.bris.ac.uk) – was designed to study the interactions between genetic susceptibilities and environmental exposures on children’s health and well-being, including health, disease, developmental, educational, psychological and social outcomes. What is described here is an example of a large, population-based, longitudinal birth cohort that was recruited specifically for the purposes of non-therapeutic, epidemiological research. The study is described, including methods of data collection, and an example given of a physical measurement that was deemed necessary to accurately characterise a particular health outcome (in this case asthma) but which was associated with administration of a pharmacological agent to healthy children with consequent risks. The regulatory framework on which this study was based is also described, as are the practical considerations of carrying out the physical testing, including parent and child interactions, understanding and satisfaction.

The Avon Longitudinal Study of Parents and Children (ALSPAC)

The study arose as a consequence of a meeting of the World Health Organisation (Europe) in 1985, at which a decision was made to develop a longitudinal survey strategy that could be used to determine what were the current problems in child health and development, and how they may be prevented. On the basis of this decision, a multi-centre European study was designed: the European Longitudinal Study of Pregnancy and Childhood (ELSPAC). The Avon Longitudinal Study of Parents and Children has developed and substantially extended the ELSPAC protocol while remaining an integral component of the European project. The primary aim of these studies is to understand the ways in which the physical and social environments interact, over time, with genetic inheritance to affect children’s health, behaviour and development.