Background Perinatal lead (Pb) exposure is associated with adverse cognitive and behavioral outcomes that may be mediated by altered brain structure and function. Childhood Pb exposure has been associated with persistent impacts on adult white matter microstructure. The objective of this study was to assess the impact of perinatal Pb exposure on white matter microstructure in children using diffusion tensor imaging (DTI). Methods This study took place in the ELEMENT cohort in Mexico City. We randomly selected 20 subjects at age 6 years for a magnetic resonance imaging (MRI) pilot study. DTI images were acquired with a 3T Philips Achieva scanner using gradient echo planar imaging. A voxel-wise statistical analysis for diffusivity measures, including fractional anisotropy (FA), was performed along major white matter tracts. All 20 subjects had blood biomarkers of Pb collected during 2nd and 3rd trimesters and at delivery (umbilical cord blood). We examined correlations between Pb biomarkers and FA values. To capture associations between perinatal Pb exposure and within-brain variability at different time points, we focused on mean FA and standard deviation (SD) of FA across 48 template regions of interest (ROIs); the latter metric captures bidirectional effects that may discretely increase or decrease FA values. Linear regression models examined the association of 2nd, 3rd-trimester and cord blood Pb levels, FA and SD of FA from the ROIs. Results Pb levels in 2nd trimester blood were positively correlated with increased global FA after controlling for multiple comparisons (p < 0.05). Higher cord blood Pb was associated with increased FA (B = 0.010, p = 0.05) and increased variability of FA (B = 0.0014, p = 0.07). Discussion These pilot data suggest changes in white matter microstructure associated with perinatal Pb exposure. Pathological alterations can decrease or increase FA, thus our pilot findings may be consistent with neurotoxic effects of perinatal Pb exposure.
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