The global cost of lead exposure in 2019 was estimated to be US$6 trillion, equivalent to 7% of global GDP

New analysis indicates exposure to lead might have caused 5.5 million adult deaths from cardiovascular disease and the loss of 765 million IQ points in children under the age of five worldwide in 2019.

However, the global impact of lead exposure could be far greater than previous estimates suggest, according to analysis published in The Lancet Planetary Health journal.

Up to 95% of the effects were in low and middle-income countries (LMICs), with children losing an average of 5.9 IQ points during their first five years of life.

The findings show that the global health effects of lead exposure could be similar to the estimated health effects of PM2.5 outdoor ambient and household air pollution combined, and three times greater than the health effects of unsafe drinking water, sanitation, and handwashing.

Lead author of the study, Bjorn Larsen says that lead exposure has continued to cause huge impacts on human health, despite most countries banning the use of leaded petrol more than 20 years ago.

“What is concerning about our study is that it indicates these damaging health effects are much greater than we previously thought and that they come at a very high economic cost, especially in low- and middle-income countries. Efforts to address the impacts of lead exposure must reflect that these are as significant as those posed by PM2.5 outdoor ambient and household air pollution,” Larsen adds.

The study was funded by the Korea Green Growth Trust Fund and the World Bank’s Pollution Management and Environmental Health Program. It was carried out by researchers from the World Bank.

Despite the fact that lead-containing petrol has been phased out around the world, exposure to the toxic metal still poses major global health risks, especially in LMICs.

Key sources of exposure include lead acid battery recycling, metal mining, food, soil and dust, leaded paint, cookware from recycled materials, lead-glazed pottery and ceramics, spices, toys, cosmetics, electronic waste, fertilizers and cultured fish feed.

The presence of each of these sources varies greatly across countries, and each source’s contribution to population blood lead levels (BLLs) needs to be better understood in most LMICs in order to develop effective exposure mitigation plans.

IQ loss in LMICs due to lead exposure is nearly 80% higher than a previous estimate, while deaths from cardiovascular disease are six times higher.

The global cost of lead exposure in 2019 was estimated to be US$6 trillion, equivalent to 7% of global GDP. In LMICs, it was equivalent to more than 10% of GDP, or twice as high as in High-Income Countries (HICs).

The overwhelming majority of health impacts and economic costs from lead exposure are in LMICs, highlighting an urgent need for improved monitoring of exposure and exposure source identification, accompanied by relevant legislative responses and public health policies.

The new analysis says that the global health effects of lead exposure are on a par with PM2.5 outdoor ambient and household air pollution combined, and three times greater than those posed by unsafe drinking water, sanitation, and handwashing.

The study is the first to estimate lead exposure’s global health burden and cost in terms of IQ loss and deaths from cardiovascular disease in both LMICs and HICs.

Exposure to lead can seriously harm young children’s health, including damage to the brain, slowed development, and learning difficulties. In adults, lead exposure can increase people’s risk of cardiovascular disease – which accounts for almost 95% of deaths linked to lead exposure – as well as chronic kidney disease and learning disabilities.

No previous research had assessed the global health impacts and economic costs of IQ loss in young children and cardiovascular disease deaths in adults caused by exposure to lead.

The authors of the new study used BLL estimates from the Global Burden of Disease (GBD) 2019 study to estimate the global health impacts and costs of lead exposure. This provides estimated average BLLs in 183 LMICs and HICs, accounting for 99.9% of the world’s population.

The analysis estimates that lead exposure contributed to 5.5 million deaths from cardiovascular disease globally in 2019, or 30% of all cardiovascular disease deaths. This is more than six times higher than the GBD 2019 estimate of 850,000 CVD deaths from lead exposure. Of these, 90% were in LMICs. As the analysis did not include deaths from high blood pressure – and because lead exposure also increases the risk of dying from causes other than cardiovascular disease – the true number of deaths linked to lead exposure may be substantially higher.

The analysis also suggests that lead exposure caused the loss of 765 million IQ points in children under five years old in 2019, with 95% of the losses among children in LMICs. During their first five years of life, children in LMICs on average each lose 5.9 IQ points from lead exposure. The authors estimate this can reduce these children’s total lifetime income by as much as 12%.

Analysis of the economic impact of lead exposure indicates it might have cost US$6 trillion worldwide in 2019, equivalent to 7% of global GDP. The cost was more than 10% in LMICs compared to 5% in HICs, due to higher BLLs in LMICs.

The World Bank estimated that the combined cost of PM2.5 outdoor ambient and household air pollution in 2019 was equivalent to 6% of global GDP.

More than three-quarters of the estimated economic cost (77%) of lead exposure was associated with cardiovascular disease deaths, with around a quarter (23%) due to predictions of lower future income caused by IQ loss.

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