The problems associated with children being exposed to lead are even longer lasting than originally feared, a study published in JAMA shows.
The study of more than 1,000 infants born between April, 1972 and March, 1973 in Dunedin, New Zealand, showed that children exposed to elevated lead levels continue to have problems well into their late 30s. More than half of the children had been tested for lead at age 11.
“In 565 New Zealanders observed for 4 decades, lead exposure in childhood was significantly associated with lower cognitive function and socioeconomic status at age 38 years,” the authors found. “Greater childhood lead exposure was also associated with greater declines in IQ from childhood to adulthood and greater declines relative to parents in occupational socioeconomic status.”
The research was conducted by Aaron Reuben and colleagues of Duke University, Durham, N.C.
Lead exposure among children is a global problem, even in the United States. Per the U.S. Centers for Disease Control and Prevention, about 310,000 children in the U.S. ages one to five have blood lead levels of more than 10 micrograms per deciliter. That is the level at which harmful side effects are known to occur.
High lead levels can lead to seizures, coma and even death. But until this study, the long-term effects on a child’s thinking skills and IQ into adulthood have been unknown.
“For communities that have experienced collective lead exposure events and for countries where lead exposures are still routinely above health standards, the findings raise questions about the reasonable duration and magnitude of public responses,” the authors wrote.
They stress that short-term solutions or short-lived public responses in communities where lead problems are known to exist will not address the problem long term.
The issue of lead contamination recently was thrust into the American consciousness when news of lead contamination in the water in Flint, Michigan broke.
But that may have just been the tip of the iceberg. For example, a recent analysis by Reuters reported by NBC San Diego found, “Dozens of California communities have experienced recent rates of childhood lead poisoning that surpass those of Flint.”
Per the NBC story, “The data shows how lead poisoning affects even a state known for its environmental advocacy, with high rates of childhood exposure found in a swath of the Bay Area and downtown Los Angeles. And the figures show that, despite national strides in eliminating lead-based products, hazards remain in areas far from the Rust Belt or East Coast regions filled with old housing and legacy industry.”
In an editorial accompanying the new JAMA research, David Bellinger of Boston’s Children Hospital said the blood levels in the New Zealand children hovered around 11 parts per deciliter. Mean lead levels of children in the U.S. were even higher, about 15 parts per deciliter.
For that reason, Bellinger said there is no reason to believe this research would have turned out any different had it been conducted in the U.S. “All nonessential uses of lead must be phased out to prevent its continued dispersal into the environment.”
He said that while blood screening currently identifies children with particularly high levels of lead, “Environments must be screened, in addition to children, so that the most hazardous sites can be effectively abated before rather than after a child’s exposure occurs.”