Study: Lead Drops IQ At Lower Levels Than Thought
CDC advisory committee may change federal guidelines in light of researchApr 18, 2003 | Knight Ridder Newspapers Lead poisoning may impair children's intelligence at a far lower level than is stipulated in current federal health guidelines, meaning that potentially millions more U.S. children than previously thought have lost IQ points by ingesting contaminated dust.
Not only do small amounts of the toxic metal lower a child's intelligence, but each additional unit of lead has a relatively more dramatic effect than at higher levels of exposure, according to a study published in the New England Journal of Medicine.
The study is expected to guide an advisory committee of the federal Centers for Disease Control and Prevention as it decides whether to recommend a change in policy later this year. That could include lowering the guideline which sets "a level of concern" for lead in blood or recommending new ways to prevent additional cases.
An estimated 434,000 children younger than 6 currently have blood-lead levels above the federal guideline.
That number of affected children represents about 2 percent of the U.S. population. That represents a sharp decline from the late 1970s, when nine out of 10 children had levels that high.
The improvement is attributed to the removal of lead from gasoline and to growing awareness about the dangers of lead-based paint and lead used to solder plumbing.
Yet the problem remains grave, said Bruce P. Lanphear, a study author and professor of children's environmental health at Cincinnati Children's Hospital Medical Center.
While the study does not estimate the number of endangered children with lead levels below the federal guideline, Lanphear said it was likely in the millions.
He recommended that the nation adopt a risk-prevention strategy like that used in Denmark, where houses are screened for lead hazards before children are poisoned.
Millions of older U.S. houses contain lead-based paint under layers of newer paint, and hazardous dust can be released when the paint deteriorates or when renovators sand it for repainting.