Children with urinary levels of 3-phenoxybenzoic acid (3-PBA) above the limit of detection were twice as likely to have attention-deficit/hyperactivity disorder as those with lower levels of the metabolite of several pyrethroid pesticides, according to a study.
Such data came from the National Health and Nutrition Examination Survey (NHANES) results for 687 children aged 8-15 years. Of the sample, 15% had ADHD, which the researchers defined as meeting Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria for ADHD and/or having a prior ADHD diagnosis. The limit of detection for 3-PBA was 0.1 mcg/L. It was below that level for 21% or 131 of the study’s participants. The average BPA level in the sample was 1.14 mcg/L.
Each tenfold increase in urinary 3-BPA level was associated with a 57% increase in the prevalence of ADHD. Higher 3-BPA levels also were associated with an increasing number of hyperactive-impulsive symptoms; the number of these symptoms found in children with detectable levels of 3-BPA was 77% higher than in children with nondetectable levels.
The researchers found some differences in 3-BPA levels’ associations with ADHD and the disorder’s symptoms in boys and girls. Stronger associations between urinary 3-BPA levels and ADHD were found in boys; boys with detectable levels of 3-BPA were almost three times as likely to have ADHD than other boys in the sample. In girls, the adjusted odds ratio was only 1.54.
“Our results suggest an association between childhood urinary pyrethroid pesticide biomarkers and ADHD, particularly hyperactive-impulsive symptoms, and these associations may be stronger in boys than girls,” according to Melissa Wagner-Schuman of the Cincinnati Children’s Hospital Center and her colleagues. “Given the growing use of pyrethroid pesticides and the perception that they represent a safer pesticide alternative, these results may be of considerable public importance. However, replication of findings is warranted in prospective, longitudinal studies with serial measurements of pyrethroid pesticide exposure.”
Read the full study in Environmental Health (doi: 10.1186/s12940-015-0030-y).