Neurodevelopmental outcomes at 5 years in children exposed prenatally to maternal dental amalgam: the Seychelles Child Development Nutrition Study

Limited human data are available to assess the association between prenatal mercury vapor (Hg0) exposure from maternal dental amalgam restorations and neurodevelopment of children. We evaluated the association between maternal dental amalgam status during gestation and children s neurodevelopmental outcomes at 5years in the Seychelles Child Development Nutrition Study (SCDNS). Maternal amalgam status was determined prospectively in a longitudinal cohort study examining the associations of prenatal exposure to nutrients and methylmercury (MeHg) with neurodevelopment. A total of 236 mother-child pairs initially enrolled in the SCDNS in 2001 were eligible to participate. Maternal amalgam status was measured as number of amalgam surfaces (the primary metric) and number of occlusal points. The neurodevelopmental assessment battery was comprised of age-appropriate tests of cognitive, language, and perceptual functions, and scholastic achievement. Linear regression analysis controlled for MeHg exposure, maternal fatty acid status, and other covariates relevant to child development. Maternal amalgam status evaluation yielded an average of 7.0 surfaces (range 0-28) and 11.0 occlusal points (range 0-40) during pregnancy. Neither the number of maternal amalgam surfaces nor occlusal points were associated with any outcome. Our findings do not provide evidence to support a relationship between prenatal exposure to Hg0 from maternal dental amalgam and neurodevelopmental outcomes in children at 5years of age.