Lead is known to harm children’s developing brains, and a recent study indicates that the consequences might last into old age. According to the study, lead exposure throughout childhood may result in lower cognitive abilities later in life, implying that people may develop dementia symptoms sooner.
Although scientists have long known that lead exposure causes poor cognitive and educational performance in children and adults, only a few studies have looked into the long-term effects.
The recent study, one of the first to look into the long-term effects of lead poisoning, shows that countries may witness a spike in the number of people seeking dementia care as individuals who were exposed to high amounts of lead as children grow older. Researchers discovered that among over 1,100 older Americans, individuals who grew up in cities with lead-contaminated drinking water performed worse on memory and cognitive abilities tests. Lead is a naturally occurring element that, if accumulated in the blood, can have serious health consequences. Children under six years of age are especially susceptible, as lead can harm their developing brains and create learning or behavioral issues. However, the impact of lead exposure during childhood on the aging brain is not well understood.
Once inside the body, extra lead is stored in the bones, where it “stays quietly,” according to the researchers. However, decades after the initial exposure, age-related bone loss or fractures can let some of this element into circulation.
The Research Findings
The research involved 1,089 senior citizens from the United States who participated in a long-running health study between 1998 and 2016. Warren and his team used 1940 census data with information from the US-based Health and Retirement Study (HRS), a long-term study that has tracked the mental health of thousands of adults over several decades, to determine where these people resided as kids. As a proxy for excessive lead exposure, they also plotted the locations of towns and cities with lead pipes and acidic or alkaline water.
The study, published in Science Advances, found that individuals who grew up in cities with lead-contaminated water had lower baseline cognitive functioning at age 72 than those who did not. Cognitive functioning is their capacity to learn, process information, and reason. The age difference was almost eight years.
Warren stated that the majority of people frequently consider lead to be an old issue. We tend to think of this as a problem that we have fixed because we got rid of lead paint and leaded gasoline, and we’re doing all we can to clean up the water. Unfortunately, the long-term effects of all that lead exposure might not become apparent for several decades. According to Warren, although exposure to lead in childhood does not guarantee that a person will develop dementia, it does indicate that they will likely start much lower on the cognitive impairment scale and may reach troublesome levels earlier.
The good news is that there was no difference in the pace of cognitive deterioration between the two groups. It may be because their cognition testing was done after any lead exposure-related brain damage had already occurred.
The results only demonstrated a connection between lead exposure throughout childhood and cognition in adulthood. They did not show the cause and effect. Warren, however, pointed out that early exposure could have long-term impacts in several ways, including indirect ones. Children with high blood lead levels, for instance, frequently struggle academically and behaviorally, and they are less likely than their classmates to complete high school or pursue further education. Slower mental deterioration in old age might be associated with lower academic achievement and less lifelong mental stimulation, such as cognitively demanding work.
More research is urgently needed to clearly understand the long-term effects of lead exposure throughout childhood on brain aging and to discover practical methods to lessen lead’s long-term effects.
Reference
- Lee, H., Lee, M.W., Warren, J.R. and Ferrie, J., 2022. Childhood lead exposure is associated with lower cognitive functioning at older ages. Science Advances, 8(45), p.eabn5164. https://www.science.org/doi/10.1126/sciadv.abn5164.
