August 23, 2010
Dispatch: Don’t Get So Hyperactive About Pesticides
WebMD on Friday cited a study in Environmental Health Perspective claiming that prenatal exposure to a class of pesticides known as organophosphates may increase the risk of attention deficit hyperactivity disorder (ADHD) in children, especially boys. Researchers of a related study published in the same journal say that children with lower levels of paraoxonase 1 (PON1) — an enzyme that breaks down organophosphates — are more likely to develop neurological developmental delays compared to children with higher levels of PON1.
In order to reduce exposure to these pesticides, study researcher Amy Marks, a research analyst at the University of California at Berkeley’s School of Public Health, advises parents and parents-to-be to “wash their produce thoroughly.”
ACSH’s Jeff Stier was also quoted in the WebMD article, and although he agrees with Ms. Marks’ recommendation, he doesn’t agree with the reasoning:
[The] warning to consumers that we wash produce to prevent pesticide exposure is completely beyond the scope of the study, which evaluated agricultural workers, not consumers. We should wash produce before eating it to lower risk of food-borne illness, but not to reduce the imagined risk that trace pesticides would otherwise cause ADHD. I’m concerned that studies like this will have the effect of causing parents to fear feeding healthy fruits and vegetables to their children.
“It is interesting,” ACSH’s Dr. Elizabeth Whelan observes, “that so many studies purportedly linking environmental chemicals with morbidity are published in the same journal: Environmental Health Perspectives. What do you think are the odds of this journal publishing an article showing no relationship between chemicals and ill health?”
Bob Krieger (August 23, 2010)
Media reports such as “Pesticides Linked To Hyperactivity Disorder” fall far short of demonstrating cause and effect. The issues involve not only a complex clinical assessment and diagnosis of illness in children but also advanced pesticide science as well. The clinical complexity is further illustrated by an August 2010 publication in the Journal of Health Economics concerning university studies which estimate 900,000 children have been misdiagnosed with an attention disorder.
With respect to pesticides, the amounts of possible exposure represented by the urine data are extremely small and reported only in summary form. No pesticides have been measured. The very small amounts of DAPs that are reported may represent environmental pesticide breakdown products and consumption of fruits and vegetables rather than pesticide exposure. It is very important that DAPs themselves are not pesticides, are not toxic and may be present in the urine even in the absence of pesticide exposure.
In order to more fully assess this study, complete reporting of the DAP data is essential. The summary table that is included is insufficient for evaluation of the significance of the DAP measurements reported by Berkeley investigators. Pesticide exposure in children was not shown—the “Link” is still missing!