Date of Award

1-1-2014

Language

English

Document Type

Dissertation

Degree Name

Doctor of Public Health (DrPH)

College/School/Department

Department of Epidemiology and Biostatistics

Program

Epidemiology

Content Description

1 online resource (xii, 100 pages) : illustrations (some color)

Dissertation/Thesis Chair

Millicent Eidson

Committee Members

Charlotte Drucshel, Alissa Van Zutphen, Lloyd Wilson, Barry Sherman

Keywords

Atrazine, drinking water, preterm birth, small for gestational age, Drinking water, Premature infants, Premature labor, Cryptorchism, Hypospadias, Environmentally induced diseases

Subject Categories

Environmental Health | Epidemiology | Public Health

Abstract

The prevalence of preterm birth, small for gestational age (SGA), and hypospadias has been increasing for several decades in the U.S resulting in significant morbidity and mortality and direct costs to society. Drinking water provides a mechanism for prolonged chronic exposure to environmental contaminants but is one of the least assessed environmental exposures in pregnancy and birth outcomes. To test the hypothesis that maternal exposure to atrazine through drinking water during pregnancy, or one or more trimesters of gestation, is associated with an increased risk of preterm birth, small for gestational age, cryptorchidism and hypospadias a retrospective cohort study was performed. Logistic regression modeling was used to assess the strength of the association between estimated maternal atrazine exposure through drinking water and risk for each outcome. Estimated maternal exposure to mean atrazine levels > 123 ppt in drinking water was found to be associated with a significantly increased risk for preterm birth when exposure occurred during the second trimester (OR = 1.35, 95% CI 1.20 - 1.52), third trimester (OR = 1.28, 95% CI 1.14 - 1.43), or entire pregnancy (OR = 1.29, 95% CI 1.15 - 1.45). Preterm birth was more likely to occur when maternal drinking water ever exceeded 123 ppt (OR = 1.19, 95% CI 1.09 - 1.29) compared to never exceeded 123 ppt atrazine during the second trimester and became stronger with the number of times atrazine exceeded 123 ppt, but was only significant when levels exceeded 123 ppt 3 or 4+ times (OR = 1.21, 95% CI 1.05 - 1.40; and OR = 1.35, 95% CI 1.19 - 1.54, respectively). For SGA the strongest association was for mothers whose drinking water exceeded 123 ppt atrazine 3 times during the first trimester (OR = 1.25, 95% CI 1.08 - 1.45). Estimated maternal atrazine exposure was not associated with risk for cryptorchidism or hypospadias. Our study suggests maternal exposure to mean atrazine levels > 123 ppt in drinking water during pregnancy, well below the federal maximum contaminant level, is associated with increased risk for preterm birth and supports the implementation of policies and practices aimed at reducing the levels of atrazine in drinking water supplies.

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