Francesca Biagioli A recent study links lead exposure from gasoline in the 1960s-70s to long-term memory issues and increased Alzheimer’s risk. Despite progress, no exposure level is considered safe.
If you were born between the 1960s and 1970s, you most likely breathed air laced with high levels of lead, without even realizing it. A recent study presented at the Alzheimer’s Association International Conference (AAIC) 2025 suggests that this early exposure could have lasting consequences on memory and cognitive health, even decades later.
The study
Between 1960 and 1974, lead was still a component of gasoline in the United States—and indeed in many other Western countries as well. This toxic substance was then released into the air in large quantities, particularly in urban areas with heavy traffic. As it turns out, people who grew up in these environments have about a 20% higher chance of experiencing memory issues as adults.
This claim comes from a study led by Eric Brown, MD, from the Centre for Addiction and Mental Health in Toronto. The study analyzed data from over 600,000 Americans aged 65 and older. Researchers correlated historical lead levels in the atmosphere between 1960 and 1974 with reported memory problems from the same individuals, some 50 years later.
The scientists calculated average lead levels by geographic region and compared these to self-reported memory difficulties, gathered from the American Community Survey between 2012 and 2021. Although they didn’t directly analyze the sources of lead, it’s likely that urban areas with high traffic density had higher pollution levels. In these areas, between 17% and 22% of people reported memory problems.
The findings were clear: lead left a lasting imprint on the brain, making it more vulnerable to diseases like Alzheimer’s.
Dr. Brown points out:
“Our study may help us understand the pathways contributing to the development of dementia and Alzheimer’s disease in some individuals.”
Lead was originally added to gasoline to enhance performance, until its severe negative impact on health and the environment became clear. Its phase-out began in 1975, in conjunction with the mandatory introduction of catalytic converters on new cars sold in the U.S. This process was completed over about 20 years, while in Europe, the phase-out took place later.
Long-term effects of lead exposure
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, children’s blood lead levels were 15 times higher than they are today. 88% of us had levels above 10 micrograms per deciliter, which is now considered dangerously high.”
Despite the reduction of lead in the air, other exposure sources remain, such as old paint and outdated pipes. Dr. Brown emphasizes that those who were exposed in the past should focus on reducing other risk factors for dementia, such as hypertension, smoking, and social isolation.
Further studies confirm the dangers of lead
It’s no coincidence that this new research was first presented at the Alzheimer’s Association International Conference® 2025 (AAIC®), which took place recently in Toronto. During the event, two additional studies confirmed the dangers of lead exposure.
The first study found that seniors living within about 3 miles (5 km) of industrial sites releasing lead—such as glass factories or electronics manufacturers—showed a faster decline in memory and cognitive function.
Kathryn Conlon, Ph.D., from the University of California, Davis, senior author of the study, commented:
“Our results suggest that lead exposure in adulthood may contribute to a worsening of cognitive performance over a few years. Despite significant progress in reducing lead exposure, studies have shown that no level of exposure is considered safe, and half of U.S. children have detectable lead levels in their blood. Additionally, certain regions and neighborhoods experience higher exposure.”
Another study showed how even low levels of lead can alter human brain cells, increasing the accumulation of abnormal proteins associated with Alzheimer’s, such as tau and beta-amyloid. These cellular damages persist over time, leaving the brain more susceptible to future cognitive decline.
Junkai Xie, Ph.D., lead author, stated:
“These findings help explain how lead exposure, especially in early childhood or from occupational and environmental sources, can leave a lasting molecular imprint on the brain, making it more vulnerable to age-related diseases like Alzheimer’s. Our results show that lead exposure isn’t just a short-term issue; it could set the stage for cognitive problems decades later.”
Source: AAIC
