ADHD Revised?

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A new study conducted by Harvard researchers correlates certain pesticides with an increased risk of attention-deficit/hyperactivity disorder (ADHD) in children.

Using a 95% confidence level, they determined that “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.” They studied over a thousand children.

“These findings support the hypothesis that organophosphate exposure, at levels common among US children, may contribute to ADHD prevalence,” state the authors in their article, published online by the American Academy of Pediatrics today.

“Prospective studies are needed to establish whether this association is causal,” they write.

The authors are associated with Harvard University and the University of Montreal in Canada.

The study was funded by the National Institutes of Health (NIH).

They tested potential variables which could skew the analysis which were:

gender
age (in months)
race/ethnicity
“the ratio of self-reported family in- come to the family’s appropriate poverty threshold value on the basis of Census data, recoded into 4 categories…” (PIR)
Body Mass Index
blood lead concentrations
mothers age at child’s time of birth
maternal smoking during pregnancy (yes or no)
and time since last consuming food or drink, recorded at the time of blood and urine sampling.

“Given that ADHD medication use could change the metabolism of pesticides and influence their excretion in urine, we excluded the 40 children who were taking such medication, but the results were similar (adjusted OR for 10-fold in- crease in DMAP levels: 1.80 [95% CI: 1.18 –2.76]),” write the authors.

“There was a 55% to 72% increase in the odds of ADHD for a 10-fold increase in DMAP concentration, depending on the criteria used for case identification. This association was not explained by gender, age, PIR, race/ethnicity, fasting duration, or creatinine concentration.”

“Significant amounts of DAPs have been found on several types of fruits and vegetables,” they write.

“Given that organophosphates are eliminated from the body after 3 to 6 days, the detection of DAPs in the urine of most children indicates continuing exposure,” they write. However, they later add “Given the cross-sectional nature of our analysis, we cannot rule out the possibility that children with ADHD engage in behaviors that expose them to higher levels of organophosphates.”

Bethany Stotts is a staff writer at Accuracy in Academia.