Published: Apr 5, 2013
By John Gever , Deputy Managing Editor, MedPage Today
Action Points
- More than half a million young American children in 2010 had blood lead levels exceeding 5 mcg/dL, according to the CDC.
- Note that the researchers also found that mean blood lead levels in young children had declined by about a third compared with a decade earlier.
More than half a million young American children in 2010 had blood lead levels exceeding 5 mcg/dL, now set as the new threshold for concern, the CDC reported.
On the basis of National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2010, CDC researchers estimated that 535,000 children ages 1 to 5 had at least 5 mcg/dL of lead in their blood as of 2010, according to a report appearing in the April 5 issue of Morbidity and Mortality Weekly Report.
In 1991, the CDC had set a standard of 10 mcg/dL as the threshold for concern for lead levels in young children. But the agency’s Advisory Committee on Childhood Lead Poisoning Prevention had more recently recommended that a level equal to the 97.5th percentile of the full spectrum of childhood blood lead levels would be more appropriate.
With about 850 children being tested for blood lead levels in the NHANES program each year, according to the CDC’s Mary Jean Brown, ScD, and colleagues in the MMWR report, the CDC decided to use those data as the basis for determining a new threshold for concern.
Those data, from the 2007-2010 NHANES series, indicated that the 97.5th percentile worked out to 5 mcg/dL.
Brown and colleagues also determined that mean blood lead levels in young children had declined by about one-third from a decade earlier. In the 1999-2002 NHANES series, the average among 1- to 5-year-olds was 1.9 mcg/dL (95% CI 1.8 to 2.1). It fell to 1.3 mcg/dL (95% CI 1.3 to 1.4) in the 2007-2010 data.
Both values were far below the averages in earlier NHANES cycles, they noted. Some 88% of children in this age group showed blood lead levels of 10 mcg/dL or more in the 1976-1980 series, with a mean of 15 mcg/dL.
“Substantial progress has been made over the past 4 decades in reducing the number of children with elevated blood lead levels,” Brown and colleagues wrote.
“These reductions reflect the impact of strategies coordinated and implemented at national, state, and local levels,” the researchers continued. “They include elimination of lead in vehicle emissions, elimination of lead paint hazards in housing, reduction in lead concentrations in air, water, and consumer products marketed to children, and identification and increased screening of populations at high risk.”
Still, as in previous studies, non-Hispanic black children continued to show the highest averages in the most recent data — 1.8 mcg/dL in 2007-2010, compared with 1.3 mcg/dL in both Mexican-American and non-Hispanic white participants.
Also as before, average lead levels were higher in children living in poorer households and in homes built before 1950, when lead-based paints were commonly used.
Brown and colleagues observed that lead exposure, even at relatively low levels, “can have lifelong consequences.” They recommended continued efforts to prevent childhood exposures, by remediation efforts and education to keep at-risk children from coming into contact with lead sources.
Nutritional supplements with iron and calcium, which can reduce absorption of lead, are another useful strategy, they added.
The work was funded by the CDC. All authors were CDC employees.