The magnitude, persistence and public health significance of cognitive effects of environmental lead exposure in childhood

Abstract

Although much research has been done on the effects of lead exposure on cognitive development, the magnitude, persistence and public health implications of such effects remain controversial. A literature search, in conjunction with our own work, was conducted to review these issues. Currently available evidence suggests that early exposure to environmental lead may cause a discernible effect on cognitive development, and this effect seems to persist into later childhood. No threshold is evident down to a blood lead concentration of 5 μg dl⁻¹, although there is a paucity of epidemiological data at these lower levels. An economic loss could be serious for children exposed to an excess of lead in their environment. The environmental lead problem is preventable, or, where it is already established, is remediable. It should therefore be addressed, especially in developing countries where rapid industrialisation and increased use of motor vehicles are occurring. There is clear evidence that excessive lead exposure is still a significant public health issue in most countries, particularly developing countries. The formulation of a public health strategy should seek a balance between consideration of the nature and extent of the risk to human population health, knowledge of any dose-effect threshold, estimation of socio-environmental benefits, and commitment to making the best use of existing resources. The development of such a strategy should take into account the views and priorities of all interested parties, and—most certainly—those of communities directly at risk from lead exposure. Copyright © 1999 John Wiley & Sons, Ltd.