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<h5 class="section-title" id="d6430389e184">Background</h5>
<p id="P2">Organophosphate insecticides (OPs) are used worldwide, yet despite nearly
ubiquitous
exposure in the general population, few have been studied outside the laboratory.
Fetal brains undergo rapid growth and development, leaving them susceptible to long-term
effects of neurotoxic OPs. The objective here was to investigate the extent to which
prenatal exposure to OPs affects infant motor development.
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<h5 class="section-title" id="d6430389e189">Methods</h5>
<p id="P3">30 OPs were measured in umbilical cord blood using gas chromatography tandem
mass
spectrometry in a cohort of Chinese infants. Motor function was assessed at 6-weeks
and 9-months using Peabody Developmental Motor Scales 2
<sup>nd</sup> edition (PDMS-2) (n=199). Outcomes included subtest scores: reflexes,
stationary,
locomotion, grasping, visual-motor integration (V-M), composite scores: gross (GM),
fine (FM), total motor (TM), and standardized motor quotients: gross (GMQ), fine (FMQ),
total motor (TMQ).
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<h5 class="section-title" id="d6430389e197">Results</h5>
<p id="P4">Naled, methamidophos, trichlorfon, chlorpyrifos, and phorate were detected
in ≥10%
of samples. Prenatal naled and chlorpyrifos were associated with decreased 9-month
motor function. Scores were 0.55, 0.85, and 0.90 points lower per 1 ng/mL increase
in log-naled, for V-M (p=0.04), FM (p=0.04), and FMQ (p=0.08), respectively. For chlorpyrifos,
scores were 0.50, 1.98, 0.80, 1.91, 3.49, 2.71, 6.29, 2.56, 2.04, and 2.59 points
lower for exposed versus unexposed infants, for reflexes (p= 0.04), locomotion (p=0.02),
grasping (p=0.05), V-M (p<0.001), GM (p=0.007), FM (p=0.002), TM (p<0.001),
GMQ (p=0.01),
FMQ (p=0.07), and TMQ (p=0.008), respectively. Girls appeared to be more sensitive
to the negative effects of OPs on 9-month motor function than boys.
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<h5 class="section-title" id="d6430389e202">Conclusions</h5>
<p id="P5">We found deficits in 9-month motor function in infants with prenatal exposure
to naled
and chlorpyrifos. Naled is being aerially sprayed to combat mosquitoes carrying Zika
virus, yet this is the first non-occupational human study of its health effects. Delays
in early-motor skill acquisition may be detrimental for downstream development and
cognition.
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