title: Impaired arsenic metabolism in children during weaning.
abstract: BACKGROUND
  Methylation of inorganic arsenic (iAs) via one-carbon metabolism is a susceptibility factor for a range of arsenic-related health effects, but there is no data on the importance of arsenic metabolism for effects on child development.
  
  
  OBJECTIVE
  To elucidate the development of arsenic metabolism in early childhood.
  
  
  METHODS
  We measured iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA), the metabolites of iAs, in spot urine samples of 2400 children at 18 months of age. The children were born to women participating in a population-based longitudinal study of arsenic effects on pregnancy outcomes and child development, carried out in Matlab, a rural area in Bangladesh with a wide range of arsenic concentrations in drinking water. Arsenic metabolism was evaluated in relation to age, sex, anthropometry, socio-economic status and arsenic exposure.
  
  
  RESULTS
  Arsenic concentrations in child urine (median 34 microg/L, range 2.4-940 microg/L), adjusted to average specific gravity of 1.009 g/mL, were considerably higher than that measured at 3 months of age, but lower than that in maternal urine. Child urine contained on average 12% iAs, 9.4% MA and 78% DMA, which implies a marked change in metabolite pattern since infancy. In particular, there was a marked increase in urinary %MA, which has been associated with increased risk of health effects.
  
  
  CONCLUSIONS
  The arsenic metabolite pattern in urine of children at 18 months of age in rural Bangladesh indicates a marked decrease in arsenic methylation efficiency during weaning.
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Box 210, 17177 Stockholm, Sweden.
authors.forename: Britta
authors.initials: B
authors.lastname: Fängström
authors.forename: Jena
authors.initials: J
authors.lastname: Hamadani
authors.forename: Barbro
authors.initials: B
authors.lastname: Nermell
authors.forename: Margaretha
authors.initials: M
authors.lastname: Grandér
authors.forename: Brita
authors.initials: B
authors.lastname: Palm
authors.forename: Marie
authors.initials: M
authors.lastname: Vahter
mesh_terms: D001151:Arsenic / Q000378:metabolism* / Q000633:toxicity / Q000652:urine*; D001459:Bangladesh; D002657:Child Development / Q000187:drug effects; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis*; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity / Q000652:urine*; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D012044:Regression Analysis; D014886:Weaning
chemical_list: D004785:Environmental Pollutants; D001151:Arsenic