In utero exposure to arsenic in tap water and congenital anomalies: A French semi-ecological study

Introduction: Congenital anomalies (CA) are responsible for high rates of mortality and long-term disabilities. Research on their risk factors including environmental factors is needed. Studies on exposure to arsenic (As) in tap water and the risk of CA have not provided conclusive evidence, particularly when levels of exposure were low (from 10 to 50 mu g As/L). The main objective of this study was to assess the association between exposure to As in tap water and the risk of any major CA. The secondary objectives were to assess this association for the most common types of congenital anomalies (in the heart, musculoskeletal, urinary and nervous systems). Methods: A semi-ecological study was conducted from births recorded at the University Hospital of Clermont. Ferrand, France, in 2003, 2006 and 2010. The medico-obstetric data were available at individual level. Children with congenital anomalies were identified from the database of the regional registry of congenital anomalies: the Centre d'Etudes des Malformations Congenitales Auvergne (CEMC-Auvergne). As exposure was estimated from the concentrations of As measured during sanitary control of tap water supplied in the mothers' commune of residence (aggregate data). French guidelines for As in tap water were used to identify the two groups: >= 10 mu g As/L group" and "[0-10) mu g As/L group". Multivariable logistic regression models were fit. Results: 5263 children (5.1% with a CA) were included. In stratified analysis by gender of the child, positive associations between As exposure exceeding 10 mu g/L and risk of any major CA (adjusted OR = 2.41; 95%CI: 1.36-4.14) and of congenital heart anomalies (adjusted OR = 3.66; 95%CI: 1.62-7.64) were only shown for girls. No association was found for boys. Conclusion: This French semi-ecological study provides additional arguments for the association between exposure to As exceeding 10 mu g/L in tap water and the risk of CA especially in a context of low exposure. Further studies are needed to better understand the interaction between arsenic exposure and child gender.