Who knows? Seems to me that IQs are pretty poor here in 2023.
But for people like me carrying a heavy metals burden of unknown origin, maybe it was leaded gas, maybe it was melting lead bullets in the family fireplace, etc.
2022-03-07. Emphasis added.
Leaded gasoline calculated to have stolen more than 800 million cumulative IQ points since the 1940s
A new study calculates that exposure to car exhaust from leaded gas during childhood stole a collective 824 million IQ points from more than 170 million Americans alive today, about half the population of the United States.
The findings, from Aaron Reuben, a PhD candidate in clinical psychology at Duke University, and colleagues at Florida State University, suggest that Americans born before 1996 may now be at greater risk for lead-related health problems, such as faster aging of the brain. Leaded gas for cars was banned in the U.S. in 1996, but the researchers say that anyone born before the end of that era, and especially those at the peak of its use in the 1960s and 1970s, had concerningly high lead exposures as children.
Lead is neurotoxic and can erode brain cells after it enters the body. As such, there is no safe level of exposure at any point in life, health experts say. Young children are especially vulnerable to lead's ability to impair brain development and lower cognitive ability. Unfortunately, no matter what age, our brains are ill-equipped for keeping it at bay.
Reuben's next step will be to examine the long-term consequences of past lead exposure on brain health in old age, based on previous findings that adults with high childhood lead exposure may experience accelerated brain aging.
"Millions of us are walking around with a history of lead exposure," Reuben said. "It's not like you got into a car accident and had a rotator cuff tear that heals and then you're fine. It appears to be an insult carried in the body in different ways that we're still trying to understand but that can have implications for life."
WIND: scientific models are mostly bullshit (eg COVID decimation that never happened, climate change model total fail, etc)—models are not science, they are guesses subject to wild variation due to invalid assumptions made (knowingly or otherwise), and implicit and unconscious biases, etc.
But in this case, I am sensitive to the claims, given my recent high blood lead level test results showing about 16X higher blood lead than typical.