Over half of young children tested in the United States by one lab have detectable levels of lead in their blood, according to a new study by Quest Diagnostics researchers and published in JAMA Pediatrics. Children in poverty and Black children are more likely to have detectable blood lead than non-Black children and children from more affluent communities.
The study analyzed blood samples from 1,141,441 children less than 6 years of age living in 50 states and the District of Columbia who underwent blood lead level (BLL) testing between October 2018 and February 2020.
The detection limit for the BLL test is >=1.0 micrograms per deciliter (µg/dL). The team found that 50.5% of samples had detectable levels of lead. Detectable BLLs were more common in children from zip codes with predominantly non-Hispanic Black residents (57.6% of samples) and predominantly non-white Hispanic residents (56.0% of samples), versus predominantly non-Hispanic white residents (48.7% of samples). Detectable BLLs were found in 60.2% of children living in zip codes with the highest rates of poverty, versus 38.8% of children in zip codes with the lowest rates of poverty.
Detectable BLLs were not evenly distributed at the state level, either. While nationally the rate for detectable BLL was 50.5%, 5 states dramatically exceeded that rate: Utah (73%), Iowa (76%), Michigan (78%), Missouri (82%), and Nebraska (83%).
“Our Quest analysis finds that half of American children tested had detectable lead, a substance that is not safe for children at any level,” said study author and Senior Medical Director Harvey Kaufman, MD. “Moreover, the study found that kids in areas with the highest rates of poverty are also the most at risk, highlighting the critical role of social disparities in health.”
Analysis revealed that elevated BLLs, defined as >=5.0 µg/dL, were also not evenly distributed. While the national rate was 1.9%, children in 6 states had significantly higher rates of elevated BLLs: Wisconsin (4.3%), Michigan (4.5%), Missouri (4.5%), Pennsylvania (5.0%), Ohio (5.2%), and Nebraska (6.0%).
“Public health authorities have worked commendably to reduce lead exposure for decades, yet substantial risk remains,” Dr. Kaufman said. “Our study is a cautionary tale of the enormous challenge of remediating environments following contamination with toxins dangerous to human health. Children, families, and society achieve the most benefit from interventions that ensure that the US mitigates lead exposures in homes and other settings before a child is ever exposed. In the meantime, it is vital that each and every child is screened for lead and immediate actions are taken to mitigate exposure in cases of elevated levels.”
Hauptman M, Niles JK, Gudin J, et al. Individual- and community-level factors associated with detectable and elevated blood lead levels in US children: Results from a national clinical laboratory. JAMA Pediatr. 2021 Sep 27:e213518.