A new study published in JAMA Pediatrics is reporting one half of American children under the age of six have detectable levels of lead in their blood. The research looked at recent blood test results from over one million children and is the first study of this scale to analyze minute traces of lead in blood samples.
The study was a collaboration between researchers at Quest Diagnostics and Boston Children's Hospital, and de-identified data from more than 1.1 million blood tests were analyzed. The blood tests were taken from children under the age of six, between October 2018 and February 2020, and spanned all 50 American states.
A striking 50.5 percent of children tested had detectable blood lead levels equal to or higher than 1.0 µg/dL, and 1.9 percent of children had levels equal to or higher than 5.0 µg/dL. A previous study looking at elevated blood lead levels in children between 2009 and 2015 found three percent had levels equal to or higher than 5.0 µg/dL.
This drop in elevated lead blood levels is positive, however, this is the first large-scale investigation to track levels lower than 5.0 µg/dL. While most recent concern has traditionally been directed at lead levels above 5.0 µg/dL, both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) state no safe threshold of lead exposure has been identified and any level of lead in a child’s blood can potentially lead to adverse effects.
"Given the lack of a threshold for the deleterious effects of lead in children and largely permanent effects of poisoning, prevention is extremely important,” says study co-author Jeffrey Gudin. “This means limiting exposure and testing of young children blood tested for lead – and having them retested periodically if results indicate a potentially unsafe level.”
The study also reveals lead exposure in American children can dramatically vary depending on demographics and geographical location. Nebraska, Missouri, Michigan, Iowa, and Utah all saw detectable blood levels in over 70 percent of children sampled.
Unsurprisingly, children living in areas with high levels of pre-1950s housing had significantly higher blood lead levels compared to those living in areas with mostly post-1950s housing. This affirms much lead exposure is due to old housing featuring lead pipes and paint.
An editorial from Philip Landrigan and David Bellinger accompanying the publication of the new research dubs lead exposure in children “a silent epidemic.” They call for more work from the government to remove sources of lead exposure and also point out the higher blood lead levels found in African-American and low-income neighborhoods reflect “stark disparities” still present in the US.
“These findings confirm that we still have a long way to go to end childhood lead poisoning in the United States,” write Landrigan and Bellinger. “They reconfirm the unacceptable presence of stark disparities in children’s lead exposure by race, ethnicity, income, and zip code – many of them the cruel legacy of decades of structural racism – a legacy that falls most harshly on the children and families in our society with the fewest resources.”
Morri Markowitz, a lead poisoning expert from the Children's Hospital at Montefiore, says children’s blood lead levels may have significantly dropped over the past 50 years but the goal needs to be zero, as there is no safe level of lead exposure.
"There's lead in the environment, and it persists," Markowitz said to Bloomberg. "It's way better than 50 years ago, in terms of how much lead is out there, but it's still there."
The new study was published in JAMA Pediatrics.
Source: Quest Diagnostics
