Lead poisoning from car smoke reduces IQ of half of the US population

Newly published research shows that lead exposure from car exhaust has lowered the IQ of half of the US population. And a drop in IQ scores is just the beginning of other dire consequences.

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 throughout childhood has stolen a significant number of their IQ scores, researchers say.

Car exhaust is the main way lead enters our bloodstream. Lead was added to gasoline to improve engine performance, and U.S. consumption of leaded gasoline increased rapidly in the early 1960s, peaking in the 1970s.

Exhaust fumes from cars rise into the air.

Also in the 1970s, health problems with lead became apparent. In the US, leaded gasoline was completely phased out as of January 1, 1996. But unfortunately, it was too late.

Clinical psychologist Aaron Reuben at Duke University (USA) and his colleagues at Florida State University have found that essentially all Americans born in those two decades are guaranteed claim to have been exposed to destructive 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 smoke has stolen a total of 824 million IQ points from more than 170 million living Americans. to this day, that's about half of the US population.

According to research, Americans born before 1996 may now be at increased risk of lead-related health problems, such as faster brain aging.

The researchers revealed 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 some degree of exposure. alarmingly high lead 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, it stays alive and active in the body, often for months or years.

More than 170 million Americans live with a history of lead exposure from car exhaust.

Even the smallest amount of lead can cause serious health problems. Young children, especially those under the age of 6, 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 it is inhaled as dust, or when we eat or drink water," Reuben said. In the blood, it can enter the brain by crossing the blood-brain barrier, which is the layer of cells that covers the blood vessels in the brain and controls the entry of molecules from the blood into the brain. harmful substances and invading pathogens'.

Researcher Reuben and co-authors Michael McFarland and Mathew Hauer, both professors of sociology at Florida State University, knew that understanding the impact of leaded gasoline smoke over 70 years would be a task. complex. So they chose a simple strategy.

The researchers used publicly available data on American childhood blood lead levels, leaded gasoline use, and census data to determine the lifetime burden of lead exposure for lead exposure. every American alive in 2015. From the data, they assessed the harmful effects of lead on human intelligence by calculating the IQ score lost from exposure to leaded gasoline smoke as a proxy for its effects on public health.

And the results startled them. 'Honestly, I was shocked,' Mr McFarland said, 'when I look at the numbers, I'm still in shock despite my preparation'.

Long term effects on health

As of 2015, more than half of the U.S. population had clinical manifestations of blood lead levels when they were children. This can lead to lower IQs and put them at higher risk of other long-term health impairments, such as reduced brain size, increased likelihood of mental illness, and increased risk of heart disease. cardiovascular disease in adulthood.

The toll on intelligence from lead poisoning is appalling: childhood lead exposure may have erased the United States' cumulative IQ score by an estimated 824 million points – or nearly 3 on average. each 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 researchers). public data) is even worse, averaging over 7 IQ points.

While a few IQ points reduction may seem insignificant, the researchers note that these changes are enough to move people with below-average cognitive abilities (IQ scores below 85) down to the disabled group. intelligence (IQ score below 70).