LEAD EXPOSURE IN CHILDREN
GUIDANCE FOR THE HEALTH SECTOR
First Draft prepared by
N. Graber, MD, MPH,M. Markowitz, MD andPh.Landrigan, MD, MSc
For consideration by the WHO Informal Working Group
Executive Summary
Childhood exposure to lead remains a serious public health issue throughout the world, that impacts the health and development of children in both developed and developing nations. WHO recognizes the need to educate and train health care providers at all levels in the prevention, diagnosis and management of children’s diseases linked to environmental risk factors, as well as influencing health policies. A number of country case studies illustrate dramatic declines in the blood lead levels of populations once programs to phase-out the use of lead in gasoline have been initiated. However, a tremendous amount of work remains to be done as children continue to be exposed to lead from innumerable additional sources described in this publications.
The purpose of this document is to guide public health agencies as they decide on the best approach to addressing lead exposure at an international, national and local community level. The process consists of describing the present burden of lead exposure in the population of interest, the impact that lead is having on the health of the population, - especially in children - and the economic burden placed on the society due to the large numbers of affected individuals. It continues designing an approach to eliminating lead exposure in a large portion of the population, conducting a cost-benefit analysis which illustrates the tremendous gains from eliminating lead in the environment versus the economic losses incurred from programs which either clean-up existing contamination, redesign industry to prevent further exposure, and educate the public on avoiding lead-exposure from the innumerable sources. This paper also reviews the most current scientific knowledge on lead exposure which serves as a foundation to carefully draft legislation, the crucial first step in initiating the process of protecting society’s most precious, yet most sensitive asset, children.
WHO estimates that more than one-third of the global disease burden in children is due to environmental factors and that in the specific case of environmental lead exposure, about 800.000 children per year suffer a loss of IQ points that can lead to mental retardation. Lead is a neurotoxin. It irreversibly alters the developing brains of children and this outcome has been demonstrated in studies which look at the impact lead has on the intelligence of lead-exposed children. This effect has been clearly demonstrated by following large cohorts of children for long periods of time in well-controlled, carefully planned prospective studies. Moreover, lead’s impact on intelligence has been shown to occur at any blood lead level, with the greatest impact occurring at the lowest blood lead levels. A recently published pooled-analysis of data from 6 large cohorts in 3 countries, (United States, former Yugoslavia and Australia), has confirmed this finding. The implication is that programs which address lead exposure must aim to not only reduce exposures, but completely eliminate lead in the environment accessible to children.
Screening for lead can be universal or targeted. Screening can be directed at identifying lead-exposed individuals or populations, or it can be used to identify lead contaminated environments. Decisions about the approach to screening are based on knowledge of the distribution of lead in the population and the environment and on the availability of resources to manage lead-exposed individuals or lead-contaminated environments. Identifying lead-exposed populations or individuals is not a substitute for primary prevention.
The blood lead level (BLL) of concern has been declining over the years as the evidence for health effects becomes stronger at the lower levels of exposure. It is becoming clear, that any level blood lead level in childhood is associated with some degree of damage to the developing brain. The discussion is nowadays shifting from reducing exposures to completely eliminating lead from the environment.
Although many measures can be taken to reduce the lead-related disease burden in children, the most effective ones will result from health initiatives that are coordinated with environmental and developmental approaches. The information contained in this publication aims at enabling the health sector to act more effectively on preventive actions and policies, while enhancing intersectoral partnerships to address this major public health problem.
