Lead Poisoning Poses Significant Global Health Threat, Potentially Causing Over Five Million Annual Deaths

Lead poisoning has a more significant global health impact than previously recognized, potentially causing over five million annual deaths, akin to the threat posed by air pollution, according to a recent modeling study by World Bank economists to assess lead exposure's impact on heart disease deaths and IQ loss on children.

This research suggests that children in developing countries exposed to lead may lose nearly six IQ points on average. Although leaded gasoline has been banned worldwide, people can still encounter this toxic metal through various sources like food, soil, cookware, cosmetics, and car batteries.

Cost of Lead Exposure to Human Health

The study, titled "Global Health Burden and Cost of Lead Exposure in Children and Adults: A Health Impact and Economic Modelling Analysis" published in The Lancet, calculated that children under the age of five collectively experienced a loss of 765 million IQ points worldwide in 2019 due to lead poisoning, with 95 percent of these losses occurring in developing nations.

This figure is nearly 80% higher than previous estimates. The World Bank researchers assessed the economic cost of lead exposure at $6 trillion in 2019, equivalent to seven percent of the global gross domestic product.

To conduct their analysis, the researchers relied on estimates of blood lead levels in 183 countries, drawn from the significant 2019 Global Burden of Disease study.

Unlike previous research, which primarily considered lead's impact on heart disease by raising blood pressure, this new study examined various other ways lead affects the heart, including arterial hardening that can lead to strokes. This comprehensive approach resulted in higher estimates.

Roy Harrison, an expert in air pollution and health at the University of Birmingham in the UK, who was not involved in the research, found the study "interesting but subject to many uncertainties." For instance, the relationship between blood lead levels and heart disease is based on a US survey, and generalizing these findings globally is challenging.

Harrison also noted that the model relied on estimations rather than direct tests of lead in blood for many developing countries. While the results could be of substantial public health importance if confirmed, Harrison considers them an intriguing hypothesis at this stage.

New Study Dubbed 'A Wake Up Call'

Richard Fuller, President of the non-governmental organization Pure Earth, pointed out that when surveys in developing countries did conduct blood lead tests, they often discovered higher lead levels than what the new study estimates. He added that the findings suggest that the impact of lead may be more severe than the report indicates.

Furthermore, Bjorn Larsen acknowledged that there is still a limited understanding of the precise contribution of different lead sources to blood contamination. Fuller noted that a portion of this information gap was addressed in a recent Pure Earth report, which analyzed 5,000 samples of consumer products and food across 25 developing countries.

The report revealed significant lead contamination in items such as metal cookware, ceramic utensils, paint, cosmetics, and toys. Fuller emphasized that these kitchen-related items are a substantial source of lead poisoning in poorer countries.

Childhood Lead Exposure in Americans in 1960-1970 Results to Below Average IQ

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