NEW YORK —
After lowering the standard, the Centers for Disease Control and Prevention went back and looked at old blood tests from 1,653 children under 6 to determine how many would have lead poisoning under the new definition.
About 3 percent of them — or about 50 kids — had blood lead levels higher than the new threshold of 5 micrograms of lead per deciliter of blood. Using that result, CDC officials calculated that an estimated 535,000 young children have lead poisoning.
A year ago, when the threshold was 10 micrograms, experts estimated that somewhere between 77,000 and 255,000 young kids had high levels of lead.
These estimates have focused on children younger than 6, who have been considered most at risk of neurological problems due to lead.
Overall, the new CDC study found lead counts were higher on average in children who were poor or African-American, said the CDC’s Mary Jean Brown, an author of the study.
Those kids are more likely to live in old housing or in neighborhoods with greater exposure to lead, she added.
The good news: Even with the lower threshold, lead poisoning appears to still be declining. Years ago, some local health departments began tracking the number of kids with blood levels at 5 or greater, and they say those numbers have been dropping steadily.
However, it’s likely that many children with lead poisoning have not been diagnosed. In the CDC study, elevated lead levels were discovered for a third of the children only when they were tested by researchers.
“When you look for it, you find it,” Columbia’s Rosner said.
Once lead poisoning is diagnosed, doctors often refer parents to local health departments to get their homes checked out to try to find the source of the problem. But as demand for investigations grows, there’s less money to pay for them. Congress last year cut CDC lead program’s budget from about $29 million to $2 million. That ended CDC grants to local health departments for their programs.