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PRI's Environmental News Magazine

Respiratory Woes

Air Date: Week of August 10, 2007

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African American and Hispanic children are exposed to higher levels of lead than Caucasian children. Children of color also exhibit higher levels of asthma. Coincidence? Maybe not, according to a new study linking lead exposure and asthma. Host Steve Curwood talks with Dr. David Lawrence of the New York State Department of Health.

Transcript

CURWOOD: Lead is not only found in certain products from China, but also in old paint, dust and soil. According to the Centers for Disease Control, African American and Hispanic children have four times as much lead in their blood as Caucasian children. Also, American kids of color are two to four times as likely to visit the hospital emergency room for asthma attacks than their white peers. So, is there a connection? Well, a new study from the New York State Department of Health shows that there is a link between lead and increased allergies and asthma. Joining me now is Dr. David Lawrence, who worked on the study. Hello, sir.

LAWRENCE: Hello

CURWOOD: Now your research is showing that beyond the health impacts we already know about lead, most of which are neurological, asthma is now a concern. What drew you to investigate this possible link?

LAWRENCE: For one thing there’s amazing commonality between the central nervous system, the brain and the immune system. The lead has mainly been thought of as having the major effect on the central nervous system. It’s been known for a long time that it also influences the hematopoietic system. That is the system from which all the immune cells are derived.

CURWOOD: How exactly did you do this research?

LAWRENCE: We isolated bone marrow from mice and put it in culture in the presence and absence of factors that would allow the cells to differentiate, to develop into the various cells of the immune system, in the presence and absence of lead.

CURWOOD: So it turns out that when you exposed the cells that were going to develop into certain immune cells to lead, they developed in a way that enhances an allergic response?

LAWRENCE: Yes, so the type of cell that is derived in the presence of lead has a greater capacity to stimulate an allergic response, yes.

CURWOOD: Let’s talk about the dosage here. Your study found significant results at exposure levels that are quite a bit higher than the limits for humans at the Centers for Disease Control has set.

LAWRENCE: Yes they were much higher.

CURWOOD: What would you expect to see at lower exposure levels?

LAWRENCE: Well when were doing these types of research experiments we usually use higher doses for shorter periods of time cause we’re impatient and can’t wait as long as it might take in the regular environment to produce a response. The doses we were using are much higher but we’ve also seen effects of lead on the developing immune system at much, much lower doses as well.

CURWOOD: I’m seeing that African American and Hispanic kids visit the emergency room for asthma attacks two to four times more often than Caucasian children. And also seeing that the according to CDC anyway, that children in these minority groups also have blood levels of lead that are four times higher than white children, so there’s a correlation here?

LAWRENCE: Yes. I mean it’s mostly housing but there’s a correlation also in terms of what causes allergic responses. Stress in and of itself can enhance an allergic response. We also know that there’s more overall stress in lower social economic stratum. There’s poor living conditions on the whole where there is more potential lead exposure in the household. There may be heating problems, there may be more noise problems. So there’s a number of factors, and stress in and of itself, in terms of psychological stress, can also have an influence on the overall process.

CURWOOD: Any concern that lead, exposure to lead may in fact be related to processes that enhance the chances of somebody getting or promoting cancers?

LAWRENCE: Well it could go both ways. One, lead is interfering with the type of immunity that would normally be considered immune surveillance. That is, as the immune system looks around for bacteria and virus to kill off, as I mentioned lead inhibits that. With regard to the other side of the coin, there was a published report many years ago with a woman that was exposed to large doses of lead because she was taking bone meal supplementation at a time when the bone meal was not being regulated very well and so had a higher amount of lead in the bone meal and she ended up dying of leukemia. But there was never any definitive evidence that it was the lead that actually caused the leukemia.

CURWOOD: What sort of research do you see following on the heels of what you have done here, and what you looking forward to studying going forward?

LAWRENCE: I think what we’re now mainly looking towards is something we’ve talked a little bit about already and that is the commonality between the central nervous system and the immune system. And that is the problem that we see with lead causing IQ modifications and behavioral variance. Might it be due to the fact that lead is altering the immune system and it’s the immune system that’s having an influence on the central nervous system? Or in fact could it be the fact that lead is having an effect on the central nervous system and the central nervous system is influencing the immune system. We know that psychological stress can alter our immune capacity and immune reactivity can bring on certain psychological problems. So we’re now beginning to evaluate how environmental factors like lead can influence what we refer to as the neuro-immune network, the interaction between the central nervous system and the immune system.

CURWOOD: So in other words lead might make us feel kinda crazy and that hurts our immune system or lead might hurt our immune system which would make us crazy?

LAWRENCE: Yes. Exactly. You can’t win sometimes.

CURWOOD: I guess not. Dr. David Lawrence is a researcher at the Wadsworth Center for the New York State Department of Health. Thank you so much sir.

LAWRENCE: Thank you. It was very nice talking with you.

[MUSIC: Keola Beamer “E Ku’u Morning Dew” from ‘Hawaiian Slack Key Guitar Masters’ (Dancing Cat Records – 1995)]

 

Links

Click here for a link to the study on lead

 

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