Prenatal Pesticide Exposure Affects Brain Structure

Prenatal exposure to chlorpyrifos is associated with altered brain structure, function, and metabolism, with a duration into late childhood and adolescence. These findings were recently published in JAMA Neurology.

Researchers conducted a prospective, longitudinal pregnancy cohort study to examine the relationship between prenatal chlorpyrifos exposure and brain structure, function, and metabolism among school-aged children. The researchers used a regression model adjusted for covariates to test the effects of prenatal chlorpyrifos exposure on cortical thickness, white matter volumes, and cerebral blood flow. To correct for multiple comparisons, a parametric, cluster size-based familywise error rate was used.

The study sample consisted of 270 children of African American or Dominican descent who had usable magnetic resonance imaging (MRI) data and measured chlorpyrifos levels at birth. Participants were between 6.0 and 14.7 years of age at the time of MRI, with a mean (SD) age of 10.38 (1.12) years, and 54.5% were girls.

The researchers found an inverse association between prenatal chlorpyrifos exposure and cortical thickness in the dorsoparietal region. In contrast, higher levels of chlorpyrifos exposure were associated with increased thickness in the frontal, temporal, and posteroinferior cortices. These regions of cortical thickening also exhibited reduced white matter volume. Additionally, higher prenatal chlorpyrifos exposure was linked to decreased blood flow across most gray and white matter regions.

To assess behavioral outcomes, the researchers used a regression model adjusted for relevant covariates. Higher chlorpyrifos levels were significantly associated with poorer performance on measures of fine motor speed (finger tapping) and motor programming (finger sequencing), with associations reaching statistical significance (all P <.0001).

Study limitations included reliance on self-reported questionnaires, potential for selection bias, possibility of confounding factors, and lack of generalizability.

“Prenatal CPF exposure was associated with altered differentiation of neuronal tissue into cortical gray and white matter, increased myelination of the internal capsule, brainwide impaired metabolism, and poor motor performance that endured into late childhood and early adolescence, likely as a result of [chlorpyrifos]-induced oxidative stress and inflammation,” the study authors concluded.

Disclosures: Study authors declared affiliations and reported disclosures in this manuscript. Please see the original reference for a full list of author disclosures.