Bookmark and Share May 25, 2010 - Dave Mulder

Pesticide exposure linked to ADHD

Organophosphates are a class of pesticide that disrupts the nervous system of insects. Though organophosphates quickly degrade when exposed to light, air, and soil, small amounts can be detected in food.

A new study in the scholarly journal Pediatrics reports a link between organophosphate pesticide exposure and attention-deficit/hyperactive disorder (ADHD). ADHD is a developmental disorder in children characterized by behavior such as difficulty focusing, impatience, and impulsivity. Diagnosing ADHD is a fairly controversial subject in its own right, so we won’t dive into it any further.

The researchers conducted secondary data analysis on results from the National Health and Nutrition Examination Survey (NHANES), a nation-wide household survey with complex sampling procedures.

Of 1139 children between age 8 and age 15, 12% to 15% met the diagnostic criteria for any ADHD subtype. This group was then compared to to all the children who did not meet diagnostic criteria for ADHD.

Organophosphate concentration was measured through chemical analysis of urine provided by participants as part of NHANES. Though there are several metabolite markers for organophosphates, dimethyl alkylphosphate (DMAP) was more consistently detected in these samples and therefore provided the best unit for statistical comparison.

The researchers found that a 10-fold increase in DMAP concentration corresponded to a 55% to 72% increase (depending on case identification criteria) in the odds of ADHD.

As with any study, there are limitations. Chief among these flaws is that NHANES only provided a single point in time. To establish time-order causality, a longitudinal set of data would provide the basis for a much stronger argument. Additionally, it is possible that ADHD behavior leads to children consuming more foods with organophosphate pesticides.


Bouchard, Maryse F., Bellinger, David C., Wright, Robert O., Weisskopf, Marc G. Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pesticides. Pediatrics 2010 0: peds.2009-3058

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