Bugs And Kids: Indoor Insecticide Use Linked To Childhood Cancers, Study Finds

I just threw out my spray can of Raid for flying insects. With kids in the house, I never did like the idea of spewing toxic stuff around, and only ever used it when a bug was driving me to feral insanity. Now, after reading the paper just out in this week's issue of the journal Pediatrics, I'll stick with the flypaper and swatter no matter how intense my irritation.

The paper concludes that the sum of previous research suggests a significant link between indoor pesticide use and childhood cancer.

To be more exact, senior author Chensheng Lu says the results "suggest that when kids are exposed to pesticides — especially a group of pesticides we call insecticides — in the indoor residential environment, kids have 43 to 47 percent more chance of having childhood cancers, specifically leukemia and lymphoma."

Dr. Lu is an associate professor of environmental exposure biology at the Harvard T.H. Chan School of Public Health. He acknowledges the study's limitations, in particular that it could find only 16 relevant previous papers to analyze. But, he says, it showed "consistent results in terms of the positive correlation between exposure to insecticide indoors and childhood cancer."

The study does not aim to "cause fear in parents," Lu says. "But it's to give you a precautionary principle that those exposures can be prevented, can be mitigated or can be completely removed."

Of course, these findings only heighten the dilemma for households or schools that are tormented by pests, with infestations too fierce to be dented by anything but the big toxic guns. Are we supposed to just let the roaches and mosquitoes run wild?

Dr. Lu points out that preventive measures like window screens and hole-plugging can help, and among pesticides, some applications are safer than others — for example, "bait houses" that try to attract the pest inside a box-like structure to be poisoned.

"The worst-case scenario in terms of indoor pesticide use and human exposure it to use some kind of fogger," he says. "Also, some kind of open-air application, a broadcast application, a spray can. Those are bound to significant exposures."

The paper does not report a link between outdoor pesticides and childhood cancer, but that doesn't mean outdoor pesticides are proven safe for children, Lu says; the lack of a significant link could stem from the lack of good data.

But indoor risks may in fact be greater than outdoor, he added, because when toxic chemicals are sprayed indoors, the residents tend to be close by, and "there's very little dilution. In other words, the pesticide will stay in the indoor environment for a long period of time."

Exactly how pesticides may cause cancer remains relatively unclear, Lu said, but we do understand something about why children may be particularly vulnerable: "One way to detoxify pesticides once you're exposed to them is through the liver," and small children, whose livers are not fully developed, "don't have the capability or capacity to detoxify those pesticides."

So what is to be done? Along with preventive measures, Lu suggests trying "non-chemical-based treatments" before resorting to chemical pesticides, and if those fail, trying to use isolated chemical treatments like bait boxes.

In the bigger picture, he notes that the state of New York passed a law two years ago to limit pesticide use in parks, playgrounds and schoolyards. "People can take control in their households," he says, "but once the kids go to school or the park or the playground, it's really up to the school district and municipalities to decided whether they continue to use pesticides or not."

Readers, thoughts, reactions, experiences?

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Carey Goldberg Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.



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