Manganese in Levels in Tooth Dentin and Neurodevelopment in a Cohort of Young Mexican- American Children

Abstract

Manganese in Levels in Tooth Dentin and Neurodevelopment in a Cohort of Young Mexican- American ChildrenAbstract Number:2289 Robert Gunier*, Manish Arora, Michael Jerrett, Asa Bradman, Kim Harley, Nina Holland, Alan Hubbard, Brenda Eskenazi Robert Gunier* University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , Manish Arora Mount Sinai School of Medicine, United States, E-mail Address: [email protected] Search for more papers by this author , Michael Jerrett University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , Asa Bradman University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , Kim Harley University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , Nina Holland University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , Alan Hubbard University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author , and Brenda Eskenazi University of California, Berkeley, United States, E-mail Address: [email protected] Search for more papers by this author AbstractIntroduction: Manganese (Mn) is an essential nutrient but can be neurotoxic at high exposure levels. Previous studies have observed associations between Mn exposure and children’s neurodevelopment, primarily using concurrent exposure measurements in blood or hair. Prenatal and postnatal Mn exposures have not been evaluated together in a prospective study of neurodevelopment in young children.Methods: We measured Mn levels in prenatal and postnatal dentin from children’s shed teeth. We examined the relationship between prenatal and postnatal exposure and children’s performance at 6, 12 and 24-months of age on the Bayley Scales of Infant Development mental and psychomotor development indices. We explored the possibility of an inverted U-shaped association with neurodevelopment since Mn is an essential nutrient. We also evaluated potential interactions between Mn exposure and blood lead concentrations as well as maternal iron status during pregnancy.Results: We observed a negative association between postnatal Mn levels in dentin and psychomotor development at 6-months of age. The relationship followed an inverse U- shaped association with the strongest effect observed when comparing the highest tertile of Mn levels in teeth to the middle tertile of Mn levels in teeth (-3.6 points; 95% Confidence Interval: -6.9, -0.2). Prenatal Mn levels in dentin were associated with both mental and psychomotor development at 6-months only among children whose mothers’ were iron deficient during pregnancy. We did not observe a significant interaction with prenatal or postnatal blood lead concentrations in this cohort. There was no relationship between Mn levels in dentin and mental or psychomotor development at 12 and 24 months of age.Conclusions: We report a modest decrease in psychomotor development at 6-months of age with early postnatal Mn exposure. Iron status during pregnancy was an important effect modifier of prenatal Mn exposure and neurodevelopment at 6-months of age.