Low-level lead poisoning is a major risk to the cardiovascular health of adults, but it is also affecting the cognitive development of children, something that is happening even at concentrations of this metal that were previously considered safe, as shown a new study carried out by researchers from the Mailman School of Public Health at Columbia University, Simon Fraser University in Canada and Harvard Medical School, together with Boston Children’s Hospital.
In the case of children, lead exposure is responsible for the annual loss of approximately 765 million IQ points worldwide. In addition, this poisoning increases the risk of premature birth, cognitive deficits, and attention deficit hyperactivity disorder (ADHD), according to study data published in the New England Journal of Medicine.
In adults, lead can cause chronic kidney failure, hypertension and cardiovascular disease, and is estimated to be responsible for 5.5 million deaths annually from heart disease. “The global burden of disease due to lead exposure is alarming,” says Ana Navas-Acien, professor and chair of Environmental Health Sciences at Columbia in a note published by Columbia University.
“While the rate of heart disease has decreased in industrialized countries, it has increased in developing nations over the past 30 years. One in three children in the world (more than 600 million children) suffers from lead poisoning,” adds the researcher.
Eliminate sources of lead in the environment
Lead is easily absorbed into the bodies of growing babies. In adults, 95% of retained lead is stored in the skeleton, and factors such as menopause or hyperthyroidism can release accumulated lead, causing an increase in blood concentrations.
“The dramatic decline in IQ and increased risk of death from cardiovascular disease, even at the lowest blood lead concentrations, along with widespread exposure, demonstrate the need for strategies to eliminate lead poisoning,” said Bruce Lanphear of Simon Fraser University.
“Although lead exposure has decreased almost 100% since the 1970s and its use was banned in the US and Europe, exposure persists due to the presence of traces of lead paint in older homes, gasoline with lead in the soil, lead leaching from water pipes and emissions from industrial plants and incinerators,” he adds.
“The drastic decrease in IQ and the increased risk of death from cardiovascular diseases demonstrate the need to adopt strategies to eliminate lead poisoning”
Some people face an increased risk of lead poisoning; for example, young children living in older, poorly maintained homes are at risk of ingesting lead through paint chips. People who drink water from faucets connected to lead pipes or live near industrial areas are also at risk. In the US, air lead concentrations are typically higher in racially segregated communities than in integrated areas.
The level of blood lead considered harmful has been revised downwards several times, from 100 µg/L to 35 µg/L in 2021 in children, although a safe level has not yet been identified. According to David Bellinger of Harvard Medical School and Boston Children’s Hospital, there is no evidence of a safe threshold.
The authors emphasize the need for more research on the relationship between lead exposure and cardiovascular disease. However, long-term, cumulative exposure appears to be a stronger indicator of risk than short-term exposure measured in blood.
To protect the population, Navas-Acien and his colleagues highlight the importance of eliminating sources of lead in the environment, including replacing lead pipes, banning leaded fuels for aviation, reducing the presence of lead in food , and eliminate lead paint in older homes.
