Those born prior to 1996, the year the United States banned lead from gasoline, suffer from a lowered iQ which is attributable to the gasoline additive, according to a new research study published in the Proceedings of the National Academy of Sciences.
Overall, the researchers from Florida State University and Duke University found, childhood lead exposure cost America an estimated 824 million points, or 2.6 points per person on average.
Certain cohorts were more affected than others. For people born in the 1960s and the 1970s, when leaded gas consumption was skyrocketing, the IQ loss was estimated to be up to 6 points and for some, more than 7 points. Exposure to it came primarily from inhaling auto exhaust.
Principal study author Michael McFarland, an associate professor of sociology at Florida State University and a faculty member of the university’s Center for Demography and Population Health, called the number of people affected by lead exposure “staggering.”
“This is important because we often think about lead as an issue for children, and of course it is,” he said. “But what we really wanted to know is what happens to those children who were exposed?”
In many cases, McFarland said, a 2 to 3 point IQ difference is nominal, unless an individual is on the lower side of IQ distribution.
“If you’re more toward cognitive impairment, a couple points can mean a lot,” he said.
In addition to lower IQ, lead has been linked to heart and kidney disease as well.
Lead poisoning has been an issue in paint and water as well with the debacle in Flint, Michigan a few years ago, one of the more egregious examples.