New Recommendations for Lead Levels in Children
An advisory panel to the Centers for Disease Control and Prevention recommends a new standard for blood lead levels in children. Kim Dietrich was on the advisory committee. He tells host Bruce Gellerman that the acceptable lead levels should be about half what current standards allow.
GELLERMAN: Lead is a powerful and well-known environmental neurotoxin. But now a panel of experts says the federal level for lead poisoning in kids is way too high and needs to be a lot lower. Kim Dietrich is director of epidemiology at the University of Cincinnati Department of Environmental Health.
He’s also a member of the advisory panel that recommended that the Centers for Disease Control and Prevention lower the lead standard.
DIETRICH: We need a new standard because there have been studies, epidemiological studies that show there are effects well below the previous level of concern of 10-15 micrograms per deciliter.
GELLERMAN: So, this new standard that you’re recommending would be what, precisely?
DIETRICH: It’s certainly going to be at least as low as five micrograms per deciliter.
GELLERMAN: And the current standard is…?
DIETRICH: 10-15. So when I started to do this research 31 years ago, there were very few children in the United States that were below 10 micrograms per deciliter. Now, in the recent studies, we have more children who have blood lead concentrations below 10 micrograms per deciliter. But those studies still see significant dose-effect relationships even at levels below 10 micrograms per deciliter.
GELLERMAN: In terms of the brain imaging of kids who have, say, five to 10 micrograms per deciliter - what do you see?
DIETRICH: So, my studies generally involve children that have blood lead concentrations above ten. But we do see children who had higher blood lead concentrations when they were infants and toddlers as adults.
They have lower volumes of cortical gray matter in the frontal lobes which are associated with judgment, reasoning, anticipation of consequences - what we call the executive functions - and in the same children, we find higher rates of juvenile delinquency and adult criminality - this is all well-documented and published in peer-reviewed journals.
GELLERMAN: So, let me ask you - is there any safe level of lead in a kid’s blood?
DIETRICH: No one knows. The only safe level would be zero but that’s impossible because we’ve been exposed to lead for centuries. But I think that the committee arrived at a very appropriate reference level where pediatricians should be alerted to the possibility of environmental sources for a child, and alerted to talk with the parents about preventing future exposure.
GELLERMAN: But I thought they got the lead out of paint, they got the lead out of gasoline - where are kids getting exposed to lead?
DIETRICH: Mainly from paint - they got lead out of paint in the mid-1970s. But one of the useful aspects of lead is that it makes paint very durable and it stays there almost forever, so it continues to be on the interior surfaces and exterior surfaces and it’s in the soil and the dust.
People often think of children as eating paint chips, but it’s not paint chips that's the problem, it’s the lead dust in these homes that’s the real problem because it sloughs off the wall over-time, gets into the dust, and even if you clean it up, it will appear again several weeks later because it continues to come off the walls.
GELLERMAN: So, right now, something like a quarter of a million kids are classified as being…
DIETRICH: This will probably expand the number of children within the reference range to about half a million. It will probably double the number of children who are at five to about half or above. One of the things that the committee tried to do was to put the emphasis on the environment rather than the child as a barometer of the environment - that we need to eliminate lead hazards in the first place, in order to eliminate the developmental deficits associated with childhood lead poisoning.
I was involved with the clinical trial, for example, that tried to use drugs to extract the lead from children’s bodies after they had been exposed, and what we found from these studies is that it’s really important to prevent the lead exposure in the first place. Once it occurs, the effects seem to be largely irreversible at least by pharmacological means.
GELLERMAN: So, what is the practical effect of this recommendation to the CDC?
DIETRICH: You know, my hope is that children who have a history of lead poisoning will be followed up as if they had other diseases that might affect their neuro development. If they have problems in terms of their development, they will receive the kinds of services they need to remediate any developmental deficits they have in terms of reading or attention or other deficits that we know are associated with early exposure to lead.
GELLERMAN: Kim Dietrich is director of epidemiology at the University of Cincinnati’s Department of Environmental Health. Thank you very, very much.
DIETRICH: You’re very welcome, thank you.
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