Exposure to arsenic in tap water and gestational diabetes: A French semi-ecological study

Introduction: The increase in the prevalence of gestational diabetes mellitus (GDM) and its consequences for mother and children prompts research on their risk factors including environmental factors. Studies on exposure to arsenic (As) in tap water and the risk of GDM 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 GDM. Methods: A semi-ecological study was conducted from births recorded at the University Hospital of Clermont-Ferrand, France, in 2003, 2006 and 2010. Individual medical/obstetric data were available. 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 groups potentially exposed, designated As + ( 1014 As/L) and As - ( < 10 mu g As/L). Multivariate logistic regression analysis was performed. Results: 5053 women (5.7% with a GDM) were included. Overall, women in the As + group had a higher risk of GDM than those in the As - group (adjusted OR = 1.62; 95%CI: 1.01-2.53). Stratified analysis of pre-pregnancy body mass index (BMI) showed a positive association only for obese or overweight women (adjusted OR = 2.30; 95%CI: 1.13-4.50). Conclusion: This French semi-ecological study provides additional arguments for an association between As exposure and the risk of GDM in particular in a context of low exposure. Further studies are needed to assess a potential interaction between As exposure and body mass index.