Get ready for some concerning findings.
Leaded gasoline was a common fuel in the U.S. from the 1920s until the 1970s. It was phased out after it became clear that it posed risks to both the environment and human health.
It took a long time for the full effects of lead exposure to be understood. New research suggests troubling news: if you were in an area with elevated lead levels in the air when leaded gas was at its peak, particularly between 1960 and 1974, your chances of facing memory issues later in life increase by 20%.
“Research indicates that a significant number of people in the U.S., probably more than 170 million, were exposed to high lead levels as children,” said the chief scientific officer at the Alzheimer’s Disease Association. “This study further highlights the link between lead toxicity and brain health in older adults.”
Lead was added to gasoline in the early 20th century to enhance engine performance and curb the knocking sounds in engines. However, it turned out to be detrimental, especially for children, who faced various developmental and behavioral challenges.
Adults weren’t spared either, suffering from neurological and reproductive issues, along with ongoing soil and water contamination.
Sales of leaded fuel steadily decreased over two decades, culminating in a full ban in 1996.
In a new investigation, researchers from the University of Toronto analyzed historical air lead levels across the U.S. They correlated this data with memory difficulties reported by over 65,000 residents from 2012 to 2021.
The findings revealed that between 17% and 22% of those living in areas with moderate to high atmospheric lead experienced memory problems.
“Back in 1976, children had lead levels in their blood that were 15 times higher than what we see today,” noted the senior author of the study. “Surprisingly, 88% of our population still has levels considered dangerously high.”
Presenting at the International Conference of the Alzheimer’s Disease Association, researchers suggested that individuals worried about past lead exposure should focus on minimizing other dementia risk factors, such as high blood pressure, smoking, and isolation.
Currently, over six million Americans contend with dementia, a condition that progressively undermines memory, focus, and judgment, contributing to over 100,000 deaths annually.
Unfortunately, measuring long-term lead exposure proves challenging. Blood lead levels primarily reflect recent or ongoing exposure. While lead does accumulate in bones for much longer, assessing those levels isn’t straightforward.
Some studies have attempted to measure lead in bones using a specialized technology, but, of course, it’s not available for public use and remains largely a research tool.
Furthermore, leaded gasoline still finds use in certain aircraft and racing vehicles, while lead-based pipes and paints create ongoing public health issues in various regions.
Another study presented at this same conference indicated that lead exposure could facilitate the buildup of harmful proteins in the brain associated with Alzheimer’s disease.
Lastly, research found that older individuals living near lead-releasing facilities—like those that produce glass or electronics—may face greater cognitive challenges than those farther away.
“Our results indicate that lead exposure in adulthood can negatively impact cognitive abilities in a relatively short timeframe,” said a senior research author from UC Davis. “Despite the progress we’ve made in reducing lead exposure, there’s simply no safe level of lead, and sadly, many children still show detectable lead levels in their blood.”
