Tanya Froehlich, MD.

Tanya Froehlich, MD

A commonly used household pesticide could initiate or aggravate attention deficit hyperactivity disorder (ADHD) in some children.

The finding, reported by Cincinnati Children’s researchers and published online in Environmental Health in May, 2015, found that pyrethroid pesticide exposure increased hyperactivity and impulsivity, particularly in boys with ADHD.

Pyrethroids have been used increasingly since the U.S. Environmental Protection Agency banned organophosphate pesticides from residential use in 2000. Pyrethroids are now the most commonly used for residential and public health pest control.

“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,” says Tanya Froehlich, MD, a developmental pediatrician at Cincinnati Children’s and the study’s corresponding author.

Although considered safer than the banned organophosphates, pyrethroid exposure in animal studies has shown increased hyperactivity, impulsivity and abnormalities in the dopamine system of male mice. Dopamine is a brain neurochemical involved in many activities, including ADHD.

The researchers studied data on 687 children ages 8 to 15, taken from a 2000-2001 national health survey. The survey included information on children’s ADHD symptoms and urine samples testing for the pesticide exposure biomarker 3-PBA.  Boys with detectable 3-PBA were three times as likely to have ADHD than those without the biomarker. Hyperactivity and impulsivity increased by 50 percent for every tenfold increase in 3-PBA levels in boys. Biomarkers in girls did not correlate with increased ADHD.

Although the findings are significant, Froehlich cautions that further study is needed to determine their implications for public health.

“Given that pyrethroids are non-persistent and rapidly metabolized, measurements over time would provide a more accurate assessment of typical exposure,” she says.