Children with exposure to significant amounts of organophosphate pesticides have an increased risk of developing Attention-deficit/Hyperactivity Disorder (ADHD), according to a study conducted at the University of Montreal and Report in the June, 2010 issue of Pediatrics.
According to Dr. Maryse Bouchard, the lead researcher, a ten-fold increase in the concentration of the most common metabolites of the pesticide was associated with a 1.55 increase in the likelihood of having ADHD.
This finding was independent of age, ethnicity, economic level, gender, fasting or kidney function.
They researchers wrote,” These findings support the hypothesis that organophosphate exposure, at levels common among U.S. children, may contribute to ADHD prevalence.”
This particular class of pesticide is known to interfere with brain function by altering the functioning of acetylcholine, a key chemical involved with thinking and cognition.
Also, previously animal studies have found a link between exposure to organophosphates and hyperactivity.
Humans are exposed to pesticides through our drinking water, food and home use. The primary sources for infants and children is through the diet, as vegetables and fruits contain pesticide residue.
Because their developing brain is more vulnerable, and their smaller size, the doses per boy weight exposure are higher in children compared to adults.
The researchers reviewed data from the National Health and Nutrition Examination Survey (NHANES) from 2000 to 2004. They analyzed 1,139 children from the ages of 8 to 15 who were representative of the general population.
There were 119 children with the accepted criteria diagnosis of ADHD, based on a telephone parent interview. Twenty nine additional children were taking ADHD medications, but did not meet the diagnostic criteria.
Their urine was evaluated for the organophosphate metabolites. A 10 fold increase was associated with greater odds of meeting the ADHD diagnostic criteria.
And the children with the highest levels of the metabolite had nearly a two fold increase of having ADHD compared with children without detectable levels of the metabolites.
Pediatrics-Bouchard M, et al “Attention-deficit/hyperactivity disorder and urinary metabolites of organophosphate pesticides” Pediatrics 2010: DOI 10. 1542/peds.2009-3058