Household Pesticide Linked to ADHD in Boys?

A commonly used household pesticide is reportedly linked to attention deficit hyperactivity disorder (ADHD) in children and young teens, particularly boys, according to a new study.

Although ADHD is most commonly defined by a person's inability to pay attention, these new findings showed that pyrethroid pesticide exposure was more associated with hyperactivity and impulsivity. Regardless, scientists are concerned.

"Given the growing use of pyrethroid pesticides and the perception that they may represent a safe alternative, our findings may be of considerable public health importance," Tanya Froehlich, a developmental pediatrician at Cincinnati Children's Hospital Medical Center, who was involved in the research, said in a news release.

Back in 2000-2001, the US Environmental Protection Agency (EPA) banned households from using the two most commonly used organophosphate (organic compounds containing phosphorus) pesticides at the time due to health concerns. However, that caused people to turn to pyrethroid pesticides, which are now the most commonly used pesticides for residential pest control and public health purposes. They are also increasingly used in agriculture.

Pyrethroids have often been seen as a safer choice because they are not as acutely toxic as the banned organophosphates. Meanwhile, some animal studies have suggested that pyrethroid exposure affects hyperactivity, impulsivity and abnormalities in the dopamine system in male mice. Dopamine is a neurochemical in the brain thought to be involved in many activities, including those that govern ADHD.

During this latest study, researchers looked at data on nearly 700 children ages 8-15 from the 2000-2001 National Health and Nutrition Examination Survey (NHANES). To determine pesticide exposure, they used random urine samples.

ADHD was determined by meeting criteria on the Diagnosic Interview Schedule for Children, a diagnostic instrument that assesses 34 common psychiatric diagnoses of children and adolescents.

It turns out boys with urinary 3-PBA, a biomarker of exposure to pyrethroids, were three times as likely to have ADHD compared with those without detectable 3-PBA. Not to mention hyperactivity and impulsivity increased by 50 percent for every 10-fold increase in 3-PBA levels in boys.

Girls, on the other hand, don't have to worry because for them biomarkers were not associated with increased odds of ADHD diagnosis or symptoms.

"Our study assessed pyrethroid exposure using 3-PBA concentrations in a single urine sample," Froehlich said. "Given that pyrethroids are non-persistent and rapidly metabolized, measurements over time would provide a more accurate assessment of typical exposure and are recommended in future studies before we can say definitively whether our results have public health ramifications."

The results were published in the journal Environmental Health.

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