Lead poisoning from car fumes reduces IQ by half of US population
Exhaust fumes from the car rise into the air. Photo: iStock
Lead-based paint and lead-contaminated air, water, and soil are common sources of lead poisoning in children. Americans’ exposure to lead-contaminated car fumes during childhood has stolen large swathes of their IQ scores, researchers say.
Car exhaust is the primary way lead enters our bloodstream. Lead was added to gasoline to improve engine performance, and US leaded gasoline consumption increased rapidly in the early 1960s, peaking in the 1970s.
Also in the 1970s, the health problems of lead became apparent. In the US, leaded gasoline was completely phased out starting January 1, 1996. But sadly, it was too late.
Clinical psychologist Aaron Reuben at Duke University (USA) and his colleagues at Florida State University have found that virtually all Americans born within those two decades are guaranteed to claim to have been exposed to damaging levels of lead from vehicle exhaust.
Their new study, published in the journal Proceedings of the National Academy of Sciences, calculates that childhood exposure to lead-contaminated car fumes has stolen a total of 824 million IQ points from more than 170 million living Americans. of the US population.
According to research, Americans born before 1996 may now be at higher risk of lead-related health problems, such as premature brain aging.
The researchers found that anyone born before the end of 1996, and especially those who lived at the height of leaded gasoline use in the US in the 1960s and 1970s, had very high levels of lead exposure when they were young.
Deadly Consequences
Lead is a neurotoxin that can alter the normal functioning of the central nervous system. Health experts say there is no safe level of lead exposure at any point in life.
This element is a silent killer, staying alive and active in the body, often for months or years.
More than 170 million Americans live with a history of exposure to lead from car exhaust.
Even the smallest amount of lead can cause serious health problems. Young children, especially those under 6 years of age, are particularly susceptible to lead poisoning, which can affect mental and physical development. And at very high levels, lead poisoning can be deadly.
Lead can enter the bloodstream when inhaled as dust, or when we eat or drink water. In the blood, it can enter the brain by crossing the blood brain barrier, which is a layer of cells that covers blood vessels in the brain and controls the entry of molecules from the blood into the brain, preventing harmful substances and attacking pathogens. “.
Researcher Reuben and co-authors Michael McFarland and Mathew Hauer, both professors of sociology at Florida State University, know that understanding the impact of 70 years of leaded gasoline fumes will be a complex task. So they chose a simple strategy.
The researchers used publicly available data on American children’s blood lead levels, leaded gasoline use, and census data to determine the lifetime burden of lead exposure for lead exposure of every living American in 2015. From these data, they assessed harmful effects of lead on human intelligence by calculating lost IQ scores from smoke exposure from leaded gasoline as a proxy for its effect on public health.
And the results surprised them. “Honestly, I was shocked,” said Mr McFarland, “when I saw the numbers, I was still in shock even though I had prepared myself.”
Long term effect on health
In 2015, more than half of the US population had clinical manifestations of blood lead levels when they were children. This can lead to a lower IQ and put them at higher risk of other long-term health disorders, such as reduced brain size, increased chances of mental illness, and increased risk of heart disease, cardiovascular disease in adulthood.
The amount of intelligence resulting from lead poisoning is dire: childhood lead exposure may have wiped out the United States’ cumulative IQ score by an estimated 824 million points – or an average of nearly 3. per person.
According to the researchers’ calculations, people born in the mid to late 1960s could lose up to 6 IQ points, and children with the highest blood lead levels (8 times the current minimum – according to the National Institutes of Health). ) was even worse, averaging more than 7 IQ points.
While some of the reductions in IQ points may seem insignificant, the researchers note that these changes are sufficient to transfer people with below-average cognitive abilities (IQ scores below 85) to the handicapped, intelligent group (IQ scores below 70).
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