Associations of Maternal Urinary Arsenic Concentrations during Pregnancy with Infant and Child Mental, Psychomotor, and Cognitive Development: The HOME Study

Abstract

Background and aims Arsenic exposure during pregnancy may increase the risk for intellectual deficits in children, but limited data exists from prospective epidemiologic studies, particularly at low arsenic exposure levels. We investigated the association between prenatal urinary arsenic concentrations and childhood cognitive abilities in the Health Outcomes and Measures of the Environment (HOME) Study. Methods We used anion exchange chromatography coupled with inductively coupled plasma mass spectrometry detection to measure arsenic species content in pregnant women’s urine. The summation of inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) refers to ∑As. We longitudinally assessed children’s cognitive function (n = 260) longitudinally at 1, 2, and 3 years using Bayley Scales of Infant and Toddler Development, at 5 years using Wechsler Preschool and Primary Scale of Intelligence, and at 8 years using Wechsler Intelligence Scale for Children. Results We observed a modest decrease in mental development index and full-scale intelligence quotient at ages 3 and 5 years with each doubling of ∑As (median and IQR of 3.63 and 2.40-5.86 µg/L) with estimated score (ß) differences and 95% confidence interval (CI) of -1.8 from -4.1 to 0.5 and -2.5 from -5.1 to 0.0, respectively. This trend was stronger among children whose mothers had lower iAs methylation capacity and low urinary arsebonetaine concentrations. Conclusions Our findings suggest that exposure levels relevant to the general US population may adversely affect children’s cognitive abilities. Keywords arsenic; neurodevelopment; cognitive; Bayley Scale of Infant Development; Wechsler Preschool and Primary Scale of Intelligence; in utero exposure; Mental development index; Full scale intelligence quotient.