Thursday, December 05, 2024 - A history of lead in gasoline may be behind tens of millions of mental health conditions in the United States, according to new research.
The
study published Wednesday, December 4, in The Journal of Child Psychology and
Psychiatry estimates that about 151 million mental disorder diagnoses in the US
are attributable to lead. The exposure likely would not have happened had lead
not been in gasoline,
“We’ve
shifted the curve in the population for mental health problems, so that
everyone has a greater liability in the mental illness symptoms, and that some
people who were already at risk are going to develop diagnosable disorders
sooner, more often or more kinds,” said co-author of the study Dr. Aaron
Reuben, assistant professor of clinical neuropsychology at the University of
Virginia.
Cars ran
on gasoline containing lead starting in the 1920s, and the US did not start
phasing out the substance until the 1980s, after substantial evidence of harm
over the decades, according to the US Energy Information Administration.
But in
the world today gasoline with lead continues to fuel some planes, race cars,
and farm and marine equipment.
“The
people who were exposed are not in the history books,” Reuben said. “Millions
of Americans are walking around with an unknown, invisible history of lead
exposure that has likely influenced for the worse how they think, feel and
behave.”
Scientists
have accumulated research over the last century showing that lead is harmful to
almost every organ system, Reuben said.
In a
previous study, he and a team used data on childhood blood-lead levels, leaded
gas use, and population statistics to estimate childhood lead exposure and
found that half of the US population were exposed to adverse levels of lead
early in life.
The
number of people impacted might be unexpected to many people, said Dr. Bruce
Lanphear, a population health scientist at Simon Fraser University in Canada
with expertise in lead poisoning. He was not involved in the research.
“Given
their caveats and limitations, I think they’ve done a thorough job of trying to
estimate exposures,” he said.
One such
limitation was that researchers did not measure all possible exposure sources,
meaning that the results may actually underestimate the problem, Lanphear
added.
“We have
not been able to fully understand how those exposures influenced health and
disease across the century,” Reuben added.
Lead is
a potent neurotoxin and can disrupt brain development in many ways that can
impact most types of mental health problems, including anxiety, depression and
ADHD, he said. But people were also likely impacted in ways that cannot be
diagnosed.
“It also
changed personalities. We believe that (lead exposure) makes people a little
less conscientious –– so less well organized, less detail-oriented, less likely
to be able to pursue their goals in an organized way, and more neurotic,”
Reuben added.
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