Prenatal Exposure to Metals Mixtures and Neurobehavioral Outcomes at Age 7 from the Project Viva Birth Cohort

摘要

Background: Lead (Pb), manganese (Mn), and methylmercury are known neurotoxic metals and often co-exist in the environment. Less is known about their interactive and joint effects on specific childhood neurobehavioral domains, particularly for prenatal exposure. Aims: To evaluate the joint effects of prenatal exposure to multiple metals on mid-childhood neurobehavior. Methods: We measured Pb, Mn, selenium (Se) and mercury (Hg) concentrations in maternal 2nd trimester erythrocytes from 252 mother-child Project Viva participants in Massachusetts, USA. Parents and teachers rated child behaviors with the Behavior Rating Inventory of Executive Function (BRIEF) during mid-childhood (median 7.7 years). We evaluated joint effects of the metal mixture on neurobehavior using Bayesian Kernel Machine Regression, adjusting for maternal, paternal and child characteristics. Results: Median erythrocyte Pb, Mn, Se, and Hg concentrations were 11 μg/L, 33 μg/L, 205.7 μg/L, 3.6 × 10-3 μg/L, respectively. We observed worse scores on parent- and teacher-rated scales with simultaneously increasing metal concentrations, suggestive of a joint effect, although not statistically significant. Se was a major contributor to associations for the Global Executive Composite and subscales. With other metals at their median, an IQR increase in In-Se was associated with a 1.3 point increase (95% Cl=0.02, 2.6) on the parent-rated organization of materials (OM) subscale indicating worse executive function. Increasing In-Pb was also associated with worse OM (parent-rated: 0.7 (-0.6, 1.9)) and working memory (parent-rated: 0.9 (-0.5, 2.3)) subscale performance. There was no evidence of interaction. Conclusion: Our findings suggest that prenatal exposure to common metal mixtures may adversely affect executive function in childhood. In our study, Se was a key contributor to the associations, highlighting the importance of evaluating health effects of multiple metals including essential elements.