Study: Lead poisoning has far greater impact on global health than previously thought

New research based on modeling has revealed that lead poisoning has a much more significant impact on global health than previously understood. The study suggests that lead exposure may be responsible for over five million deaths annually, posing a threat on par with air pollution.

Published on September 12 in The Lancet Planetary Health under the title ‘Global health burden and cost of lead exposure in children and adults: a health impact and economic modeling analysis,’ the study sheds light on the ongoing global health risks associated with lead exposure, even though significant declines in blood lead levels have occurred following the phase-out of leaded gasoline.

The study aimed to estimate the global burden and cost of intelligence quotient (IQ) loss and cardiovascular disease mortality resulting from lead exposure, marking the first time such estimates have been made. Researchers relied on blood lead level estimates by country from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. They calculated IQ loss in the global population of children under five using an international pooled analysis’s blood lead level–IQ loss function. The study also calculated the cost of IQ loss, which was determined only for the proportion of children expected to enter the labor force, represented as the present value of lifetime income loss due to IQ reduction.

Furthermore, the research estimated cardiovascular deaths among individuals aged 25 or older as a result of lead exposure using a health impact model that accounted for mechanisms other than hypertension. All estimates were categorized based on World Bank income classification and region, specifically for low-income and middle-income countries (LMICs) in 2019.

The findings indicate that children under five lost 765 million IQ points (95% CI 443–1098), and in 2019, 5,545,000 adults (2,305,000–8,271,000) died from cardiovascular disease due to lead exposure. Of the total global IQ loss and cardiovascular disease deaths due to lead exposure, 95.3% and 90.2%, respectively, occurred in LMICs. The study reveals that IQ loss in LMICs was nearly 80% higher than a previous estimate, and cardiovascular disease deaths were six times higher than the GBD 2019 estimate.