title: Chemical mixtures and children's health.
abstract: OBJECTIVE
  Humans are routinely exposed to multiple chemicals simultaneously or sequentially. There is evidence that the toxicity of individual chemicals may depend on the presence of other chemicals. Studies on chemical mixtures are limited, however, because of the lack of sufficient exposure data, limited statistical power, and difficulty in the interpretation of multidimensional interactions. This review summarizes the recent literature examining chemical mixtures and pediatric health outcomes, with an emphasis on metal mixtures.
  
  
  RESULTS
  Several studies report significant interactions between metals in relation to pediatric health outcomes. Two prospective studies found interactive effects of early-life lead and manganese exposures on cognition. In two different cohorts, interactions between lead and cadmium exposures were reported on reproductive hormone levels and on neurodevelopment. Effects of lead exposure on impulsive behavior and cognition were modified by mercury exposure in studies from Canada and Denmark. However, there is little consistency related to exposure indicators and statistical approaches for evaluating interaction.
  
  
  CONCLUSIONS
  Several studies suggest that metals interact to cause health effects that are different from exposure to each metal alone. Despite the nearly infinite number of possible chemical combinations, mixtures research represents real-life exposure scenarios and warrants more attention, particularly in the context of uniquely vulnerable children.
authors.affiliation: aDepartment of Environmental Health, Harvard School of Public Health bDepartment of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA cDivision of Environmental Health, Mt. Sinai School of Medicine, New York, New York, USA.
authors.forename: Birgit
authors.initials: B
authors.lastname: Claus Henn
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Robert O
authors.initials: RO
authors.lastname: Wright
mesh_terms: D001151:Arsenic / Q000633:toxicity; D002104:Cadmium / Q000633:toxicity; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D000013:Congenital Abnormalities / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D004781:Environmental Exposure / Q000009:adverse effects / Q000517:prevention & control*; D004785:Environmental Pollutants / Q000009:adverse effects / Q000633:toxicity*; D005260:Female; D006801:Humans; D007223:Infant; D007854:Lead / Q000633:toxicity; D008345:Manganese / Q000633:toxicity; D008670:Metals / Q000633:toxicity; D011159:Population Surveillance; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D004785:Environmental Pollutants; D008670:Metals; D002104:Cadmium; D007854:Lead; D008345:Manganese; D001151:Arsenic