Hypospadias and maternal exposure to atrazine via drinking water in the National Birth Defects Prevention study

Hypospadias is a relatively common birth defect affecting the male urinary tract. It has been suggested that exposure to endocrine disrupting chemicals might increase the risk of hypospadias by interrupting normal urethral development. Using data from the National Birth Defects Prevention Study, a population-based case-control study, the authors considered the role of maternal exposure to atrazine, a widely used herbicide and potential endocrine disruptor, via drinking water in the aetiology of 2nd and 3rd degree hypospadias. Data on 343 hypospadias cases and 1,422 male controls in North Carolina, Arkansas, Iowa, and Texas from 1998-2005 was used. Using catchment level stream and groundwater contaminant models from the US Geological Survey, we estimated atrazine concentrations in public water supplies and in private wells. Case and control mothers were assigned to public water supplies based on geocoded maternal address during the critical window of exposure for hypospadias (i.e., gestational weeks 6-16). Using maternal questionnaire data about water consumption and drinking water, the authors estimated a surrogate for total maternal consumption of atrazine via drinking water. Additional maternal covariates, including age, race/ethnicity, parity, and plurality, were then included in logistic regression analyses to consider an association between atrazine and hypospadias. When controlling for maternal characteristics, any association between hypospadias and daily maternal atrazine exposure during the critical window of genitourinary development was found to be weak or null (odds ratio for atrazine in drinking water?=?1. 00, 95% CI?=?0.97 to 1.03 per 0.04 ?g/day increase; odds ratio for maternal consumption?=?1.02, 95% CI?=?0.99 to 1.05; per 0.05 ?g/day increase). While the observed association was weak, the results suggest that additional research into a possible association between atrazine and hypospadias occurrence, using a more sensitive exposure metric, would be useful.

Authors: Winston JJ, Emch M, Meyer RE, Langlois P, Weyer P, Mosley B, Olshan AF, Band LE, Luben TJ; National Birth Defects Prevention Study. ;Full Source: Environmental Health. 2016 Jul 15;15(1):76. doi: 10.1186/s12940-016-0161-9. ;