In 2019, an estimated 5.5 million adults worldwide died from heart disease, and kids under the age of 5 lost a combined 765 million IQ points due to lead exposure, results of a new modeling study published in the journal The Lancet Planetary Health show.
Evidence shows that exposure to metals such as lead interferes with human intercellular function, resulting in oxidative stress and chronic inflammation, which can lead to hypertension, high cholesterol, and changes in the heart’s ability to contract. This puts individuals at risk of ischemic heart disease, stroke, left ventricular hypertrophy, heart failure, and peripheral artery disease.
The relative risk of cardiovascular disease deaths from lead exposure. Courtesy of The Lancet Planetary Health
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In addition to reduced IQ, lead exposure stunts brain development in children. A 2022 study shows that this can result in negative behavioral changes such as diminished attention span, increased antisocial behavior, and learning difficulties. A 2023 study found that the effects of exposure followed children into adulthood and were tied to poorer performance on standardized tests later in life.
IQ loss from lead exposure in early childhood. Courtesy of The Lancet Planetary Health
“Our estimate that 5.5 million died in 2019 from lead exposure was a major surprise,” Bjorn Larsen, a study author, environmental economist, and consultant to the World Bank, told The Epoch Times. “The reason for our higher estimate of deaths is that we included a whole range of effects of lead on the cardiovascular system that were not included in the 2019 Global Burden Disease (GBD) study.”
The estimate is six times higher than what the GBD study found despite the current research being based on the same data, Mr. Larsen said. The GBD study on lead’s effect on heart disease was exclusively measured in terms of its effect on blood pressure. The new study looked at several other ways in which lead affects the heart, such as its hardening of arteries that can lead to stroke, according to Mr. Larsen.
The study results raise serious questions about the long-term consequences of lead poisoning and how it poses a much more serious worldwide public health threat, study coauthor and World Bank Global Lead for Pollution Management and Circular Economy Ernesto Sánchez-Triana told The Epoch Times.
“There is no safe level of exposure to lead,” he said.
Global Cost, IQ Loss, and Air Pollution
The overall IQ loss wasn’t equally dispersed globally. The study revealed that more than 95 percent of IQ loss occurred in developing countries—nearly 80 percent higher than previously estimated.
The paper gathered evidence showing that the populations in low- and middle-income countries also share a significant percentage of lead exposure’s health and cost burden, with blood lead levels several times higher in low-income countries than in high-income countries.
Researchers put the economic cost of lead exposure at $6 trillion in 2019, equivalent to about 7 percent of the global gross domestic product. This estimate places lead exposure at the top of the list of environmental health risk factors and is on par with air pollution in the form of particulate matter (PM2.5), which is characterized as a mixture of tiny solid particles and liquid droplets that can be made up of hundreds of different chemicals found in the air in the form of dust, dirt, soot, or smoke, according to Mr. Sánchez-Triana.
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The study results suggest that lead exposure may be the third most significant cardiovascular disease risk factor ahead of hypertension, dietary risks, tobacco smoking, and high cholesterol, he said.
Lead Exposure and Disease
The World Health Organization says, “There is no level of exposure to lead that is known to be without harmful effects.”
While the study results are sobering, they’re not unprecedented.
Neurotoxins emitted from the poisonous metal are found just about everywhere and in everyday items ranging from ceramics, soil fertilizers, batteries, and beauty products, to water supply pipes, children’s toys, and even foods and spices.
Lead is a naturally occurring metal, but industrial processes expose us to levels we wouldn’t otherwise experience. It affects multiple body systems. Lead can enter the bloodstream and circulate to the brain, liver, kidneys, and bones, resulting in long-term, sometimes permanent, adverse health effects. In addition to cardiovascular disease, adults have an increased risk of high blood pressure and kidney damage.
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Exposure during pregnancy affects the growing fetus, potentially causing miscarriages, stillbirths, premature birth, and low birth weight. Young children are particularly at risk of the toxic effects of lead and can suffer irreversible damage to their developing brains and nervous systems.
Is There a Solution?
“Lead exposure (and, in general, chemical pollution) is one of the defining challenges of the 21st century. It affects everyone and everything,” Mr. Sánchez-Triana warned.
According to him, it could be an even more challenging problem than climate change.
“When we worry about climate change, we worry about a few greenhouse gases and climate pollutants. However, when we worry about chemical pollution, the orders of magnitude are in the tens of thousands of potentially harmful chemicals,” he said.
That’s why the World Bank is conducting analyses studying the impacts of other toxins such as cadmium, nitrogen, asbestos, and fine and ultra-fine particles with sulfur and other chemical species.
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For Mr. Larsen, the first and foremost priority is institutionalizing routine, nationwide blood lead level measurements in both children and adults.
“This must be accompanied by comprehensive identification of sources of lead exposure, especially in locations and regions with elevated blood lead levels,” he said.
Lead sources vary greatly across countries, and each source’s contribution to population blood lead levels needs to be better understood to develop effective ways to minimize its deadly dangers, Mr. Larsen said.
Mary Elizabeth Gillis is a health reporter and cardiopulmonary specialist with over a decade of experience. After graduating with her doctorate in applied physiology, she earned a master of science degree in journalism from Columbia University.
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