Association of Prenatal Chlorpyrifos Exposure with Sexually Dimorphic Differences in Anogenital Distance Among Thai Farmworker Children Público
Dang, Thomas (Spring 2022)
Abstract
Pesticides are used globally, yet prenatal exposure can unknowingly impact infants and their adulthood health. There needs to be a better understanding of adverse effects following prenatal exposure to endocrine-disrupting chemicals (EDCs). Research has focused on organophosphate insecticides and their effect on the reproductive health of newborns after maternal exposure. Anogenital Distance (AGD) measurements measured during infancy can provide a noninvasive measurement and accessible end-point marker for male and female reproductive health at birth and adulthood. AGD can be an early predictor to better treat for reproductive health complications early in life to allow these children a healthy adulthood.
We attempt to answer the overarching question of whether trimester-specific or mean prenatal exposure across pregnancy to chlorpyrifos in Thai farmworker children, as measured by its primary urinary metabolite (TCPy), is associated with sex-specific anogenital distance at 12 months of age. We hypothesized that chlorpyrifos exposure in the first trimester and averaged over pregnancy will be associated with shorter AGD in males and longer ADG in females. Identifying early markers of reproductive development through AGD could clarify the biological associations between maternal exposure and reproductive function without confounding by the many postnatal contributors to reproductive health.
Exposure was assessed by measuring its primary urinary metabolite (TCPy). Analysis included linear exposure-outcome models: trimester-specific and average exposure over pregnancy adding in covariates identified a priori. Differences in effect based upon sex were evaluated because literature demonstrates sexually dimorphic adverse effects. Focus was primarily on prenatal exposure as this critical time window of 12 months is hypothesized to drive environmental-related disease outcomes in children.
Findings were consistent with previous studies further supporting that prenatal exposure to pesticides is associated with AGD measurements. Models were produced unadjusted and then adjusted for creatinine levels to correct for urine dilution, consistent with the literature. We generally observed reductions in AGD in males and increases in females. Generally, this was observed in trimester-specific models and overall pregnancy, supported by previous studies. By understanding the effects of exposure to infants, better protective policies can protect mothers while giving their baby the best chance to a healthy and happy life.
Table of Contents
INTRODUCTION
I. Organophosphate Pesticides and Chlorpyrifos
II. Thailand Agriculture
III. Chlorpyrifos Exposure and Toxicity
IV. Anogenital Distance
V. Purpose
VI. Hypothesis and Main Question
METHODS
I. Study Population and Sample Collection
II. TCPy, Creatinine and PON Phenotpying Analysis
TCPy and Creatinine Analysis
Measurements of paraoxonase (PONase) and arylesterase (AREase)
III. Statistical Analyses
RESULTS
I. Demographics and Study Population
II. TCPy Metabolite
III. PON1 Phenotyping
IV. Associations between TCPy metabolite and AGD
DISCUSSION
I. Important Findings & Comparison to Other Studies
II. Strengths and Limitations
III. Policy Implications
CONCLUSION
TABLES AND FIGURES
About this Master's Thesis
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Association of Prenatal Chlorpyrifos Exposure with Sexually Dimorphic Differences in Anogenital Distance Among Thai Farmworker Children () | 2022-04-21 16:05:05 -0400 |
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