Rationale Millions of children worldwide are exposed to toxicants, including arsenic (As), that produce potentially irreversible intellectual and behavioural impairments. Higher concentrations of As in drinking water, urine, and hair have been associated with lower IQ, but most evidence comes from areas of high-level exposure (water As up to ~900 µg/L). There is limited understanding of how low-level As exposure (<50 µg/L) is associated with children’s cognition. Inside the body, inorganic arsenic undergoes methylation to methylarsonic acid (MMA) and dimethylarsinic acid (DMA), which are excreted in urine. Individuals vary in their methylation capacity. Thus, As exposure in persons who are poor methylators could result in more serious impairments than in those who are better at methylating As.
Aims & Objectives To examine the association of low-level As exposure with cognitive function in school children, taking into account the variability in their As methylation capacity.
Methods The study will be conducted using existing data on ~300 school children (ages 6-7 years) from Montevideo, Uruguay. In this cross-sectional study, children’s arsenic exposure (water As concentrations) and urinary arsenic concentrations (inorganic As, MMA, DMA) have been measured. Children were also assessed with a range of cognitive tests (IQ, executive functions, scholastic achievement). This study will use statistical tools (regression modelling) to investigate the association between arsenic exposure and cognitive performance in children, taking into account relevant demographic and biological predictors. Literature review will also be conducted in preparation for the publication of findings.
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