in a presentation to the World Bank. Their work was published in The Lancet Planetary Health.
As Mr. Larsen and Mr. Sánchez-Triana report, the economic consequences of increased exposure to lead are already immense, especially in low- and middle-income countries (LMICs). The study was financed by the Korea Green Growth Trust Fund and the World Bank’s Pollution Management and Environmental Health Program.
Intellectual, cardiovascular effects
“It is a very important publication that affects all of us,” pediatrician Stephan Böse-O’Reilly, MD, of the Institute and Polyclinic for Occupational, Social, and Environmental Health at Ludwig Maximilian University Hospital in Munich, Germany, said in an interview. “The study, the results of which I think are very reliable, shows that elevated levels of lead in the blood have a much more drastic effect on children’s intelligence than we previously thought.”
It is well known that lead affects the antenatal and postnatal cognitive development of children, Dr. Böse-O’Reilly explained. But the extent of this effect has quite clearly been underestimated before now.
On the other hand, Mr. Larsen and Mr. Sánchez-Triana’s work could prove that lead may lead to more cardiovascular diseases in adulthood. “We already knew that increased exposure to lead increased the risk of high blood pressure and, as a result, mortality,” said Dr. Böse-O’Reilly. “This study now very clearly shows that the risk of arteriosclerosis, for example, also increases through lead exposure.”
Figures from 2019
“For the first time, to our knowledge, we aimed to estimate the global burden and cost of IQ loss and cardiovascular disease mortality from lead exposure,” wrote Mr. Larsen and Mr. Sánchez-Triana. For their calculations, the scientists used blood lead level estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019.
They estimated IQ loss in children younger than 5 years using the internationally recognized blood lead level–IQ loss function. The researchers subsequently estimated the cost of this IQ loss based on the loss in lifetime income, presented as cost in U.S. dollars and percentage of gross domestic product (GDP).
Mr. Larsen and Mr. Sánchez-Triana estimated cardiovascular deaths caused by lead exposure in adults aged 25 years or older using a model that captures the effects of lead exposure on cardiovascular disease mortality that is mediated through mechanisms other than hypertension.
Finally, they used the statistical life expectancy to estimate the welfare cost of premature mortality, also presented as cost in U.S. dollars and percentage of GDP. All estimates were calculated according to the World Bank income classification for 2019.
Millions of deaths
As reported by Mr. Larsen and Mr. Sánchez-Triana, children younger than 5 years lost an estimated 765 million IQ points worldwide because of lead exposure in this period. In 2019, 5,545,000 adults died from cardiovascular diseases caused by lead exposure. The scientists recorded 729 million of the IQ points lost (95.3%) and 5,004,000 (90.2%) of the deaths as occurring in LMICs.
The IQ loss here was nearly 80% higher than a previous estimate, wrote Mr. Larsen and Mr. Sánchez-Triana. The number of cardiovascular disease deaths they determined was six times higher than the GBD 2019 estimate.
“These are results with which the expert societies, especially the German Society of Pediatrics and Adolescent Medicine and the German Cardiac Society, and the corresponding professional associations need to concern themselves,” said Dr. Böse-O’Reilly.
Although blood lead concentrations have declined substantially since the phase-out of leaded gasoline, especially in Western countries, lead still represents a major health issue because it stays in the bones for decades.
European situation moderate
“We need a broad discussion on questions such as whether lead levels should be included in prophylactic assessments in certain age groups, what blood level is even tolerable, and in what situation medicinal therapy with chelating agents would possibly be appropriate,” said Dr. Böse-O’Reilly.
“Of course, we cannot answer these questions on the basis of one individual study,” he added. “However, the work in question definitely illustrates how dangerous lead can be and that we need further research into the actual burden and the best preventive measures.”
In this respect, the situation in Europe is still comparatively moderate. “Globally, lead exposure has risen in recent years,” said Dr. Böse-O’Reilly. According to an investigation by the Planet Earth Foundation, outside of the European Union, lead can increasingly be found in toys, spices, and cooking utensils, for example.
“Especially in lower-income countries, there is a lack of consumer protection or a good monitoring program like we have here in the EU,” said Dr. Böse-O’Reilly. In these countries, lead is sometimes added to spices by unscrupulous retailers to make the color more intense or to simply add to its weight to gain more profit.
Recycling lead-acid batteries or other electrical waste, often transferred to poorer countries, constitutes a large problem. “In general, children in Germany have a blood lead level of less than 1 mcg/dL,” explained Dr. Böse-O’Reilly. “In some regions of Indonesia, where these recycling factories are located, more than 50% of children have levels of more than 20 mcg/dL.”
Particulate matter
According to Mr. Larsen and Mr. Sánchez-Triana, the global cost of increased lead exposure was around $6 trillion USD in 2019, which was equivalent to 6.9% of global GDP. About 77% of the cost ($4.62 trillion USD) comprised the welfare costs of cardiovascular disease mortality, and 23% ($1.38 trillion USD) comprised the present value of future income losses because of IQ loss in children.
“Our findings suggest that global lead exposure has health and economic costs on par with PM2.5 air pollution,” wrote the authors. This places lead as an environmental risk factor on par with particulate matter and above that of air pollution from solid fuels, ahead of unsafe drinking water, unhygienic sanitation, or insufficient handwashing.
“This finding is in contrast to that of GBD 2019, which ranked lead exposure as a distant fourth environmental risk factor, due to not accounting for IQ loss in children – other than idiopathic developmental intellectual disability in a small subset of children – and reporting a substantially lower estimate of adult cardiovascular disease mortality,” wrote Mr. Larsen and Mr. Sánchez-Triana.
“A central implication for future research and policy is that LMICs bear an extraordinarily large share of the health and cost burden of lead exposure,” wrote the authors. Consequently, improved quality of blood lead level measurements and identification of sources containing lead are urgently needed there.
Improved recycling methods
Dr. Böse-O’Reilly would like an increased focus on children. “If children’s cognitive skills are lost, this of course has a long-term effect on a country’s economic position,” he said. “Precisely that which LMICs actually need for their development is being stripped from them.
“We should think long and hard about whether we really need to send so much of our electrical waste and so many old cars to poorer countries, where they are incorrectly recycled,” he warned. “We should at least give the LMICs the support necessary for them to be able to process lead-containing products in the future so that less lead makes it into the environment.
“Through these global cycles, we all contribute a lot toward the worldwide lead burden,” Dr. Böse-O’Reilly said. “In my opinion, the German Supply Chain Act is therefore definitely sensible. Not only does it protect our own economy, but it also protects the health of people in other countries.”
This article was translated from Medscape’s German Edition. A version of this article appeared on Medscape.com.