If you were born between the 60s and 70s, you most likely breathed air with high levels of lead without even knowing it. A recent study presented toAlzheimer’s Association International Conference (AAIC) 2025 It suggests that this early exposure could have consequences on memory and cognitive health even after half a century.
The study
Between 1960 and 1974, in the United States – but in reality also in many other western countries, including Italy – petrol contained lead. This toxic substance was therefore released into the air in large quantities, especially in cities and areas with lots of traffic. And today we know that those who grew up in those environments have about 20% more likely to have adult memory problems.
To say it is the study conducted by Eric Brown, MD, of the Center for Addiction and Mental Health in Toronto, who analyzed the data of over 600,000 Americans at the age of 65. The researchers correlated the historical levels of atmospheric lead from 1960 to 1974 with memory problems reported by the same participants 50 years later.
Scientists have calculated the average atmospheric lead levels by geographical area, relating them to the difficulties of self-refined memory, collected by the American Community Survey between 2012 and 2021 In these areas, from 17% to 22% of people reported memory problems.
In any case, the result was clear: the lead left a lasting imprint in the brain, making it more vulnerable to diseases such as Alzheimer’s.
Dr. Brown underlines:
Our study could help us understand the paths that contribute to the development of Alzheimer’s dementia and disease in some people.
The lead was originally added to petrol to improve its performance, until the strong negative impact on health and the environment was discovered. His elimination began in 1975, in conjunction with the mandatory introduction of catalytic converters on new cars sold in the United States, and completed himself within about 20 years, while in Europe the process took place later.
Esme Fuller-Thomson, Ph.D., co-author of the study and professor at the University of Toronto, recalls:
When I was a child, in 1976, the lead levels in the blood of the children were 15 times higher than today. 88% of us had values over 10 micrograms per deciliter, now considered dangerously high.
Despite the decrease in lead in the air, other sources of exposure remain, we think for example of painted paints and pipes. Those who have been exhibited in the past should therefore try to reduce other risk factors for dementia, such as hypertension, smoke and social isolation, underlines Professor Brown.
Other studies confirm and expand the evidence on lead
It is no coincidence that the new research was presented for the first time at theAlzheimer’s Association International Conference ® 2025 (AAIC ®)which was held in Toronto in recent days. Here there has also been talk of two other studies that confirm how dangerous exposure to lead is.
The first noted that the elderly who live within about 5 km from industrial sites that release lead – such as glass factories or electronic producers – show a faster decline in memory and thought functions.
Kathryn Conlon, Ph.D., of the University of California Davis, senior author of the study, commented:
Our results indicate that lead exposure to adulthood could contribute to a worsening of cognitive performance within a few years. Despite the enormous progress in the reduction of lead, studies have shown that there is no safe level of exposure and half of the US children has detectable levels of lead in the blood. In addition, there are regions and neighborhoods with a greater exposure.
The other study instead showed how low lead levels can alter human brain cells, increasing the accumulation of anomalous proteins associated with Alzheimer’s, such as Tau and Beta-Hamiloid. These cell damage persist over time, preparing the brain to lasting vulnerability.
Junkai Xie, Ph.D., main author, said:
These results help to explain how lead exposure, especially in the first years of life or from employment and environmental sources, can leave a long -lasting molecular imprint, making it more vulnerable to age -related diseases such as Alzheimer’s. Our results show that lead exposure is not just a short -term problem; It could prepare the ground for cognitive problems decades later.
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