A new study out of Harvard (1) shows that even tiny, allowable amounts of a common pesticide class can have dramatic effects on brain chemistry. Organophosphate insecticides (OP’s) are among the most widely used pesticides in the U.S. & Canada and have long been known to be particularly toxic for children. This is the first study to examine their effects across a representative population with average levels of exposure. Findings show: Kids with above-average pesticide exposures are 2x as likely to have ADHD.
(1) Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pesticides
Objective: The goal was to examine the association between urinary concentrations of dialkyl phosphate metabolites of organophosphates and attention-deficit/hyperactivity disorder (ADHD) in children 8 to 15 years of age.
Methods: Cross-sectional data from the National Health and Nutrition Examination Survey (2000–2004) were available for 1139 children, who were representative of the general US population. A structured interview with a parent was used to ascertain ADHD diagnostic status, on the basis of slightly modified criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.
Results: One hundred nineteen children met the diagnostic criteria for ADHD. Children with higher urinary dialkyl phosphate concentrations, especially dimethyl alkylphosphate (DMAP) concentrations, were more likely to be diagnosed as having ADHD. A 10-fold increase in DMAP concentration was associated with an odds ratio of 1.55 (95% confidence interval: 1.14–2.10), with adjustment for gender, age, race/ethnicity, poverty/income ratio, fasting duration, and urinary creatinine concentration. For the most-commonly detected DMAP metabolite, dimethyl thiophosphate, children with levels higher than the median of detectable concentrations had twice the odds of ADHD (adjusted odds ratio: 1.93 [95% confidence interval: 1.23–3.02]), compared with children with undetectable levels.
Conclusions: These findings support the hypothesis that organophosphate exposure, at levels common among US children, may contribute to ADHD prevalence. Prospective studies are needed to establish whether this association is causal.
- Accepted February 23, 2010.
- Copyright © 2010 by the American Academy of Pediatrics