In their study, Bouchard and her colleagues analyzed data on pesticide exposure and ADHD in more than 1,100 American children aged 8 to 15.
Children with higher pesticide levels in their urine were more likely to have ADHD, the team found.
"The analysis showed that the higher the level of exposure [as measured by metabolites in the urine], the higher the odds of having ADHD," Bouchard added.
Just how might pesticides harm brain development? According to the authors, high doses of organophosphates may inhibit acetylcholinesterase, a nervous system enzyme. Lower doses of the pesticide may affect different growth factors and neurotransmitters.
The findings, if replicated, may provide another clue into the causes of ADHD, a condition which affects three to seven percent of school-aged children, according to the U.S. Centers for Disease Control and Prevention.
"We do have a fair amount of evidence about other causes of ADHD," Scott said. "We know that ADHD is a highly heritable disorder. At least one-third of fathers who have had ADHD in their youth have a child with ADHD."
"There are also prenatal risks such as tobacco exposure and alcohol exposure," she added. "There's also a possibility that children who are exposed to high levels of lead prior to the age of six may develop ADHD."
There's more on shielding kids from pesticides at the U.S. Environmental Protection Agency.
SOURCES: Maryse Bouchard, Ph.D., adjunct researcher, department of environmental and occupational health, University of Montreal and Sainte-Justine University Hospital Centre, Canada; Nakia Scott, M.D., clinical assistant professor, psychiatry and
All rights reserved