Pesticides Linked with Near Doubling in ADHD Risk

Montreal, QuebecResearchers are advising that parents feed their children organic produce as frequently as possible, following the results of a study just released which shows a link between attention deficit hyperactivity disorder (ADHD) in children and exposure to widely used pesticides such as malathion.

The study, a joint research effort between US and Canadian investigators, found that children who had higher concentrations of the most common dialkyl phosphate metabolites, a measure of organophosphate exposure, were nearly twice as likely to be diagnosed with ADHD compared with children who had no traces of the toxins, MSNBC.com reported.

"I think it's fairly significant. A doubling is a strong effect," Maryse F. Bouchard, a researcher at the University of Montreal in Quebec and lead author of the study published Monday in the journal Pediatrics told MSNBC.com. She says the take-home message for parents is buy organic whenever possible. "I would also recommend washing fruits and vegetables as much as possible," she said.

This is the largest study done to date on the effects of pesticide exposure on child development and behaviour. The study focused on measuring the levels of six pesticide metabolites in 1,139 children ranging in age from eight to 15 years, including 119 children diagnosed with ADHD. They were selected from the National Health and Nutrition Examination Survey between 2000 and 2004.

The results shows that children with a 10-times increase in certain metabolites that remain in the body following exposure to malathion had a 55 percent increased risk of ADHD. Furthermore, children with high levels of dimethyl thiophosphate, the most common of the six metabolites detected, were 93 percent more likely to have ADHD than children with undetectable levels of the marker.

Organophosphate pesticides work by interfering with insect's nervous systems, however they also effect humans. This class of pesticide reportedly accounts for up to 70 percent of the pesticides used in the US.