The importance of birth cohort studies to low and middle income countries.

In order to discern the causes of the health and developmental problems of children, and thence develop preventative strategies, longitudinal cohort studies offer major advantages. They can monitor the consequences of exposure to physical and psychological events and thence identify antecedents of various disorders. We describe the historical background to the development in the UK of this study design, and the uptake of longitudinal birth cohorts in low- and middle-income countries (LMICs), using the cohorts in Jamaica, South Africa and Brazil as exemplars. We describe the benefits of such studies and show how undertaking longitudinal cohort studies can have major health and financial benefits to the populations concerned. Additionally, the paper outlines the advantages of collaboration between studies and the pooling of data.