Globally, lead exposure is linked to more than 5.5 million adult cardiovascular deaths in 2019, as well as loss of 765 million intelligence quotient (IQ) points in children younger than 5 years, which cost U.S. $6 trillion in lost productivity, new research suggests.
- Global lead exposure has declined substantially since leaded gasoline was phased out, but several sources of lead remain, resulting in adverse health and economic effects, particularly in low- and middle-income countries (LMICs).
- Estimates of cardiovascular disease (CVD) deaths from lead exposure have been limited to effects of increased blood pressure, but studies show that lead exposure has cardiovascular impacts through mechanisms other than hypertension.
- Drawing from various sources and studies, researchers estimated global blood lead levels and the impact of lead exposure on CVD mortality in 2019 among adults aged 25 years or older, IQ loss in children younger than 5 years, and the related economic costs.
- Researchers estimated that there were 5,545,000 (95% confidence interval, 2,305,000-8,271,000) cardiovascular deaths in adults from lead exposure in 2019, with as many as 90.2% of these deaths in LMICs; however, this estimate may be incomplete because it does not include the effect of lead exposure on CVD mortality mediated through hypertension.
- The estimated global IQ loss in children younger than 5 years due to lead exposure was 765 million (95% CI, 443 million-1,098 million) IQ points in 2019, 95.3% of which occurred in LMICs.
- These estimates place lead exposure on a par with ambient particulate matter and household air pollution combined, and ahead of unsafe household drinking water, sanitation, and handwashing, as an environmental risk factor.
- The estimated global cost of lead exposure from CVD mortality and IQ loss combined is U.S. $6.0 trillion (range, $2.6 trillion-9.0 trillion) in 2019, equivalent to 6.9% of the 2019 global gross domestic product.
Given the magnitude of the estimated health effects of lead exposure, particularly in LMICs, “it is imperative that nationally representative periodic blood lead level measurements be institutionalized,” write the authors, adding that these measurements could be incorporated into existing household surveys.
The study was conducted by Bjorn Larsen, PhD, environmental economist and consultant to the World Bank, and Ernesto Sánchez-Triana. It was published online in The Lancet Planetary Health.
- Global blood lead level estimates may be inaccurate, given that measurements are absent for many countries.
- Certain income projections and income losses are uncertain.
- Because the study does not capture the detrimental effects of lead exposure other than IQ loss and CVD mortality, the estimates of global costs are conservative.
The study received support from the Korea Green Growth Trust Fund and the World Bank’s Pollution Management and Environmental Health Program. The authors have no relevant conflicts of interest.
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