A new US study estimates that exposure to leaded vehicle exhaust has led to a collective drop in IQ for more than 170 million Americans alive today compared to nearly a year ago. century.
Lead was first added to gasoline in 1923 to help improve the health of engines, but this was done at the expense of human health. This species was banned in most countries of the world in the year 2000.
Although the decline in IQ was small, the researchers noted that these changes were drastic enough to cause people with below-average cognitive abilities (IQ score less than 85) to be classified as having intellectual disabilities (IQ score less than 85). IQ less than 70).
The study was conducted by Aaron Rubin, a doctoral student in clinical psychology at Duke University in North Carolina with two colleagues from the University of Florida: Michael MacFarland and Matthew Hauer. The researchers found that Americans born before 1996 are more likely to have lead-related health problems today, such as accelerated brain aging.
The findings, published in the Proceedings of the National Academy of Sciences, indicate that leaded gasoline use peaked in the early 1960s and 1970s, and that children living at that time were alarmingly exposed to lead.
Because lead is a neurotoxic substance that can corrode brain cells after entering the body. There is no safe level of exposure at any stage of life to this substance. Young children are particularly affected by lead, which hinders brain development and decreases cognitive ability.
“Frankly, I was surprised,” MacFarland said. “When I look at the numbers, I’m still surprised even though I’m prepared for it.” The 170 million Americans represent more than half the population.