No link between prenatal organophosphate pesticide exposure and autism-related traits in childhood

Prenatal exposure to organophosphate pesticides does not appear to contribute to an increased likelihood of having autism-related traits in childhood, according to a study.

The study included 3,339 mother-child pairs (mean maternal age 31 years, 49.9 percent female) from 20 study sites in the Environmental influences on Child Health Outcomes (ECHO) cohort. Prenatal organophosphate pesticide exposure was determined through urinary concentrations of 3,5,6-trichloro-2-pyridinol (TCPy) and the sum of 6 dialkyl phosphate (ΣDAP) metabolites.

The outcome of parent-reported autism-related traits in children was assessed using the Social Responsiveness Scale (SRS). The SRS was administered at a mean age of 6.4 years.

Results showed inverse associations between prenatal TCPy or ΣDAP levels and SRS scores. However, these associations were attenuated and lost statistical significance after adjustment for maternal sociodemographic and behavioural factors (β per doubling of TCPy concentration, −0.13 ng/mL; β per doubling of ΣDAP, −0.42 nmol/L).

There was no evidence of effect modification by diet quality.

Researchers called for additional research to consider interactions with other factors, genetic susceptibility, higher exposures, or combined chemical mixtures, given the known adverse impacts of pesticides in other contexts.