According to a modeling study, lead poisoning has a significantly bigger influence on world health than previously imagined. According to the study, the metal is likely responsible for nearly five million fatalities per year and poses a similar threat to air pollution.
The study, titled ‘Global health burden and cost of lead exposure in children and adults: a health impact and economic modeling analysis,’ was published in The Lancet Planetary Health on Tuesday (September 12).
The study demonstrates how lead exposure is creating global health hazards despite significant drops in blood lead levels following the phase-out of leaded gasoline.
“For the first time, to our knowledge, we aimed to estimate the global burden and cost of intelligence quotient (IQ) loss and cardiovascular disease mortality from lead exposure,” the study read.
The study estimates lead’s impact on IQ Loss and cardiovascular health
According to the study’s authors, they used estimates of country blood lead levels from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019.
They used the blood lead level-IQ loss function from an international pooled analysis to estimate IQ loss in the global population of children under the age of five.
It went on to say that the researchers computed the cost of IQ loss, which was only calculated for the fraction of children predicted to enter the labor market, as the present value of lifetime income lost due to the IQ loss.
Using a health impact model, the researchers predicted cardiovascular mortality (with 95% CIs) owing to lead exposure among persons aged 25 and older.
Alarming impact of lead exposure
The model captures the “effect of lead exposure on cardiovascular disease mortality that is mediated through mechanisms other than hypertension”.
For 2019, all estimates were computed using the World Bank’s income classification and region (for low- and middle-income countries [LMICs] only).
According to the study, children under the age of five lost 765 million (95% CI 443-1098) IQ points, and 5,545,000 (2,305,000-8,271,000) people died from cardiovascular disease in 2019 as a result of lead exposure.
Around 729 million IQ points were lost, accounting for 953% of total global IQ loss, and 5,004,000 (902% of total) cardiovascular disease fatalities were caused by lead exposure in LMICs.
The study found that IQ decline in LMICs was over 80% higher than previously estimated, and cardiovascular disease fatalities were six times higher than the GBD 2019 projection.