March 8, 2022 – More than 170 million Americans – roughly half of American adults – were exposed to harmful levels of lead as children, according to a new study published in the Proceedings of the National Academy of Sciencess.
Additionally, researchers found that 90% of children born in the United States between 1951 and 1980 had blood lead levels above the CDC threshold. On average, early childhood lead exposure caused a 2.6 point drop in IQ per person.
“Most of what we consider the lost generation and the greatest generation and baby boomers have had moderate exposure to lead,” said Matt Hauer, PhD, one of the co-authors and assistant professor of sociology at Florida State University. in a report.
“Generation X was exposed to very high amounts of lead, and now Millennials and the generation after them have been exposed to very low amounts of lead,” he said.
The results were “infuriating” because scientists have long known that lead exposure is harmful, Michael McFarland, PhD, also co-author and associate professor of sociology at Florida State University, told the Associated Press.
The research team analyzed blood lead levels, census data and leaded gasoline use to understand how widespread lead exposure in young children was in the United States between 1940 and 2015. They primarily looked at lead exposure from leaded gasoline, which was the main form of exposure between the 1940s and 1980s.
They estimated that half of the US adult population in 2015 had been exposed to lead levels above 5 micrograms per deciliter, which was the CDC’s threshold at the time. More than 54 million people had been exposed to levels above 15 micrograms per deciliter and 4.5 million to 30 micrograms per deciliter, six times the threshold.
They found that estimated lead-related deficits were highest for the 21 million people born between 1966 and 1970, who had an average decline of 5.9 IQ points per person.
The United States has implemented stricter regulations to protect Americans from lead poisoning in recent decades, especially in gasoline. The study team found that blood lead levels were significantly lower than 5 micrograms per deciliter in people born since 2001.
At the same time, the public health effects of childhood exposure for older generations will last for years.
“Lead exposure in children is not just here and now. It will impact your health throughout life,” Abheet Solomon, senior program manager at the United Nations Fund, told The AP. United for children.
Childhood lead exposure is known to affect the development of mental abilities and increase the risk of high blood pressure, kidney damage and heart disease. It has also been linked to harm in pregnant women and developing children.
“The most tragic part is that we keep making the same … mistakes again,” Bruce Lanphear, MD, professor of health sciences at Simon Fraser University in Vancouver, British Columbia, Canada, told the AP.
Lanphear’s research on lead exposure also revealed a loss of mental abilities and IQ.
“First it was lead, then it was air pollution. Now it’s PFAS chemicals and phthalates (chemicals used to make plastics more durable),” he said. said “And we can’t stop long enough to wonder if we should regulate chemicals differently.”