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Number of kids diagnosed with lead poisoning could double with new CDC standard

young girl receiving a finger prick test at the doctor's office
(Image credit: Getty / SCIENCE PHOTO LIBRARY)

The Centers for Disease Control and Prevention (CDC) just adjusted its criteria for what's considered a high concentration of lead in a young child's blood, the agency announced Thursday (Oct. 28).

The change applies to kids ages 1 to 5, and it could double the number of children in that age group considered to have high blood lead levels, from about 200,000 to about 500,000, The Associated Press (AP) reported.

Doctors use a so-called Blood Lead Reference Value (BLRV) as the cutoff point for what's considered a high concentration of lead; this measurement is based on the number of micrograms of lead present per deciliter of blood. For the last nine years, the BLRV was set at 5 µg/dL, and now, that threshold has been lowered to 3.5 µg/dL, according to the CDC statement. Doctors compare the amount of lead in a child's blood against the BLRV to decide who is at highest risk for negative health effects from lead.

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Kids whose blood levels exceed the new BLRV will have "higher levels of lead in their blood" than 97.5% of kids in the U.S., according to the CDC statement. Children whose blood lead levels exceed the cutoff should receive prompt medical care to reduce their lead levels and mitigate any damaging health effects of the exposure; children with very high levels of lead in their blood can potentially receive a treatment called chelation therapy, to remove some of the lead, according to the CDC website

When children are identified as having high blood lead levels, public health officials will then be responsible for identifying and eliminating the source of the lead exposure in the children's environment, the AP reported. 

"Today's action by CDC is a reminder of how important it is for parents to ask their child's doctor about early blood lead testing, so parents can take steps to keep them safe from the toxic and irreversible effects of lead exposure," Health and Human Services Secretary Xavier Becerra said in the CDC statement. Prior to the new update, blood lead levels below 5 μg/dL may or may not have been reported to parents, so with the lower cutoff, more parents, healthcare providers and communities may be notified about dangerous lead exposure in children, the CDC notes.

Children can absorb four to five times more lead than adults do when exposed to the same source, the AP reported. Lead exposure can damage a child's developing brain and other parts of their nervous system; and the toxic metal can also slow growth and development, and cause learning, behavior, hearing and speech problems, according to the CDC

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In the U.S., lead exposure poses the biggest problem to low-income communities and Northeast and Midwest cities with older housing, but dangerous lead exposure can occur anywhere in the country, the AP reported. "Older" housing refers to homes built before 1978, the year lead-based paints were banned, the CDC notes. Other common lead-exposure sources include: soil contaminated by historical sources of lead, such as mining; contaminated pipes and plumbing materials; contaminated jewelry, toys or (often imported) candies; and lead dust brought into the home from kids' caretakers' workplaces.

"No safe [blood lead level] in children has been identified, and even low levels of lead in blood have been shown to affect learning and academic achievement, and some effects may even be permanent," the CDC statement notes. (Detailed recommendations for preventing lead exposure, testing a child's blood lead levels and caring for children with high lead levels can be found on the CDC website.)

This recent change in the definition of lead poisoning for young children has been a long time coming, according to the AP. 

After the BLRV was last adjusted in 2012, the agency pledged to review the standard every four years. Toward the end of the Obama administration, the CDC determined that the standard should be made more stringent, but the change was held up during the Trump administration when, among other hold-ups the White House Office of Management and Budget refused to sign off, Patrick Breysse, who heads the CDC's National Center for Environmental Health, told the AP.

Originally published on Live Science.

Nicoletta Lanese

Nicoletta Lanese is a staff writer for Live Science covering health and medicine, along with an assortment of biology, animal, environment and climate stories. She holds degrees in neuroscience and dance from the University of Florida and a graduate certificate in science communication from the University of California, Santa Cruz. Her work has appeared in The Scientist Magazine, Science News, The San Jose Mercury News and Mongabay, among other outlets.