Factors influencing arsenic metabolism in children

摘要

Inorganic arsenic (iAs) is metabolized through reduction and methylation. Incomplete methylation to Dimethylarsinic Acid (DMA), with elevated urinary excretion of Methylarsonic Acid (MMA), is a susceptibility factor in adults. However, little is known for children. In our mother-child cohort study in rural Bangladesh, we repeatedly measured urinary arsenic metabolites (U-As) in mothers and children (1.5,4.5 and 9 years), and evaluated main factors influencing the children's metabolism. We also measured certain toxic and essential elements in children's blood. Children had higher %DMA than their mothers, unrelated to the children's lower exposure. Nutritional status, especially factors related to the one-carbon metabolism, was influential for the children's arsenic methylation. Also selenium status, assessed as erythrocyte selenium, appeared highly influential. Available data indicate that the factors influencing children's urinary arsenic metabolite pattern differ from that in adults. Whether arsenic methylation efficiency is a susceptibility factor for arsenic toxicity in children needs further evaluation.