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Background: Studies have evaluated environmental exposure to toxic metals such as arsenic (As), cadmium (Cd), manganese (Mn), or lead (Pb) on birth size; however, information on potential effects of exposures to metal mixtures is limited. Objectives: We assessed the association between metal mixtures (As, Cd, Mn, Pb) in umbilical cord blood and neonate size in Bangladeshi children. Methods: In this birth cohort study, pregnant women who were [greater than or equal to]18 years of age with an ultrasound-confirmed singleton pregnancy of [less than or equal to]16 wk gestation were recruited from two Bangladesh clinics between 2008 and 2011. Neonate size metrics were measured at the time of delivery. Metals in cord blood were measured using inductively coupled plasma mass spectrometry. We employed multivariable linear regression and Bayesian kernel machine regression (BKMR) to estimate associations of individual metals and metal mixtures with birth size parameters. Results: Data from 1,088 participants was assessed. We found a significant negative association between metal mixture and birth length and head circumference when all metal concentrations were above the 60th and 55th percentiles, respectively, compared with the median. An interquartile range (IQR) increase in log Cd concentration {log[Cd (in micrograms per deciliter)] IQR = 2.51} was associated with a 0.13-standard deviation (SD) decrease in mean birth length (95% CI: -0.25, -0.02) and a 0.17-SD decrease in mean head circumference (95% CI: -0.28, -0.05), based on linear regression models adjusted for covariates and the other metals. An IQR increase in log Mn concentration {log[Mn (in micrograms per deciliter)] IQR = 0.69} was associated with a 0.07-SD decrease in mean birth weight (95% CI: -0.15, 0.002). Discussion: Metal mixtures in cord blood were associated with reduced birth size in Bangladeshi children. Results from linear regression models adjusted and the BKMR mixtures analyses suggest adverse effects of Cd and Mn, as individual metal exposures, on birth size outcomes. https://doi.org/10.1289/EHP7502, Introduction Prenatal exposure to environmental chemicals can disrupt fetal growth and developmental programming of organ function, thereby increasing the risk of diseases later in life (Grandjean et al. 2008). Environmental [...]

BACKGROUND; Animal studies suggest that early-life lead exposure influences gene expression and production of proteins associated with Alzheimer's disease (AD). OBJECTIVES: We attempted to assess the relationship between early-life lead [...]

BACKGROUND: Exposure to chemical mixtures is recognized as the real-life scenario in all populations, needing new statistical methods that can assess their complex effects. OBJECTIVES: We aimed to assess the joint effect of in utero exposure to arsenic, manganese, and lead on children's neurodevelopment. METHODS: We employed a novel statistical approach, Bayesian kernel machine regression (BKMR), to study the joint effect of coexposure to arsenic, manganese, and lead on neurodevelopment using an adapted Bayley Scale of Infant and Toddler Development[TM]. Third Edition, in 825 mother-child pairs recruited into a prospective birth cohort from two clinics in the Pabna and Sirajdikhan districts of Bangladesh. Metals were measured in cord blood using inductively coupled plasma-mass spectrometry. RESULTS: Analyses were stratified by clinic due to differences in exposure profiles. In the Pabna district, which displayed high manganese levels [interquartile range (IQR): 4.8,18 [micro]g/dl], we found a statistically significant negative effect of the mixture of arsenic, lead, and manganese on cognitive score when cord blood metals concentrations were all above the 60th percentile (As [greater than or equal to] 0.7 [micro]g/dl, Mn [greater than or equal to] 6.6 [micro]g/dl, Pb [greater than or equal to] 4.2 [micro]g/dl) compared to the median (As = 0.5 [micro]g/dl, Mn = 5.8 [micro]g/dl, Pb = 3.1 [micro]g/dl). Evidence of a nonlinear effect of manganese was found. A change in log manganese from the 25th to the 75th percentile when arsenic and manganese were at the median was associated with a decrease in cognitive score of -0.3 (-0.5, -0.1) standard deviations. Our study suggests that arsenic might be a potentiator of manganese toxicity. CONCLUSIONS: Employing a novel statistical method for the study of the health effects of chemical mixtures, we found evidence of neurotoxicity of the mixture, as well as potential synergism between arsenic and manganese. https://doi.org/10.1289/EHP614., Introduction Childhood exposure to neurotoxicants is a potential impediment to economic development, as it is most prevalent in developing countries, making this issue particularly poignant in countries such as Bangladesh [...]