ATRAZINE EXPOSURE FROM DRINKING WATER AND ADVERSE BIRTH OUTCOMES IN KENTUCKY, U.S.A.

Abstract

Background and Objectives: Herbicide useis widespread worldwide, with atrazine being one of the most common in the U.S.A. and other countries. Recent studies suggest a possible association betweenatrazine exposure and adverse birth outcomes. Kentucky, a largely ruralstate with high atrazine use, ranks among the highest in the U.S.A.in rates of prematurity and low birth weight.We examinedthe relationship between atrazine in drinking water andpreterm births, gestational age and birthweight. Methods: Kentucky birth certificate data were analyzed to assess birth outcomes and other individual-level covariates. Data from 2004-2006 were used for all singleton births toKentucky residents. Atrazine levels in drinkingwater were assessed at the county level using data from the Department of Water andthe Kentucky Geologic Survey.Counties were categorized into tertiles of atrazine exposure (high, moderate, low). Multivariate linear and logistic models were used to assess the potential risk contribution of atrazine to birth weight, gestational age and preterm births (<37 weeks of gestation). Results: A significant risk was observed for preterm births forwomen residing in the high versus low exposure counties while controlling for relevant individual covariates (OR= 1.26; 95% CI 1.19, 1.33). Similar results were found for gestational age as a continuous variable, with a difference of -0.20 weeks (95% C.I. -0.25, -0.16), and for birth weight, with a decrease of -25.8 grams (95% C.I. -34.9,-16.6). Conclusions: The results of this study indicated a modest association between atrazine exposure and adverse birth outcomes. The results were consistent with similar recent studies.However, due to the ecologic nature of the exposure assessment and the possibility of exposure misclassification further individual-levelresearch is strongly recommended to assess the relationship between atrazine exposure and adverse birth outcomes.