Prenatal organophosphate insecticide exposure and infant sensory function

Int J Hyg Environ Health. 2018 Apr;221(3):469-478. doi: 10.1016/j.ijheh.2018.01.010.


Background: Occupational studies suggest that exposure to organophosphate insecticides (OPs) can lead to vision or hearing loss. Yet the effects of early-life exposure on visual and auditory function are unknown. Here we examined associations between prenatal OP exposure and grating visual acuity (VA) and auditory brainstem response (ABR) during infancy.

Methods: 30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Grating visual acuity (VA) (n = 179-200) and auditory brainstem response (ABR) (n = 139-183) were assessed at 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and central conduction time, and head circumference (HC). Associations between sensory outcomes during infancy and cord OPs were examined using linear mixed models.

Results: Prenatal chlorpyrifos exposure was associated with lower 9-month grating VA scores; scores were 0.64 (95% CI: -1.22, -0.06) points lower for exposed versus unexposed infants (p = 0.03). The OPs examined were not associated with infant ABR latencies, but chlorpyrifos and phorate were both significantly inversely associated with HC at 9 months; HCs were 0.41 (95% CI: 0.75, 0.6) cm and 0.44 (95% CI: 0.88, 0.1) cm smaller for chlorpyrifos (p = 0.02) and phorate (p = 0.04), respectively.

Conclusions: We found deficits in grating VA and HC in 9-month-old infants with prenatal exposure to chlorpyrifos. The clinical significance of these small but statistically significant deficits is unclear. However, the disruption of visual or auditory pathway maturation in infancy could potentially negatively affect downstream cognitive development.

Keywords: Auditory processing; Chlorpyrifos; Neurodevelopment; Pesticide; Visual acuity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chlorpyrifos / adverse effects*
  • Chlorpyrifos / blood
  • Cohort Studies
  • Developmental Disabilities / blood
  • Developmental Disabilities / etiology
  • Environmental Pollutants / adverse effects
  • Environmental Pollutants / blood
  • Evoked Potentials, Auditory, Brain Stem / drug effects*
  • Female
  • Fetal Blood / metabolism
  • Hearing / drug effects
  • Hearing Disorders / blood
  • Hearing Disorders / etiology
  • Humans
  • Infant
  • Insecticides / adverse effects*
  • Insecticides / blood
  • Male
  • Maternal Exposure / adverse effects*
  • Mothers
  • Organophosphorus Compounds / adverse effects
  • Organophosphorus Compounds / blood
  • Phorate / adverse effects
  • Phorate / blood
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Sensation / drug effects*
  • Vision Disorders / blood
  • Vision Disorders / etiology
  • Vision, Ocular / drug effects
  • Visual Acuity / drug effects*


  • Environmental Pollutants
  • Insecticides
  • Organophosphorus Compounds
  • Phorate
  • Chlorpyrifos