title: Cadmium exposure and neurodevelopmental outcomes in U.S. children.
abstract: BACKGROUND
  Low-level environmental cadmium exposure in children may be associated with adverse neurodevelopmental outcomes.
  
  
  OBJECTIVE
  Our aim was to evaluate associations between urinary cadmium concentration and reported learning disability (LD), special education utilization, and attention deficit hyperactivity disorder (ADHD) in U.S. children using National Health and Nutrition Examination Survey (NHANES) data.
  
  
  METHODS
  We analyzed data from a subset of participants in NHANES (1999-2004) who were 6-15 years of age and had spot urine samples analyzed for cadmium. Outcomes were assessed by parent or proxy-respondent report. We fit multivariable-adjusted logistic regression models to estimate associations between urinary cadmium and the outcomes.
  
  
  RESULTS
  When we compared children in the highest quartile of urinary cadmium with those in the lowest quartile, odds ratios adjusted for several potential confounders were 3.21 [95% confidence interval (CI): 1.43, 7.17] for LD, 3.00 (95% CI: 1.12, 8.01) for special education, and 0.67 (95% CI: 0.28, 1.61) for ADHD. There were no significant interactions with sex, but associations with LD and special education were somewhat stronger in males, and the trend in the ADHD analysis was only evident among those with blood lead levels above the median.
  
  
  CONCLUSIONS
  These findings suggest that children who have higher urinary cadmium concentrations may have increased risk of both LD and special education. Importantly, we observed these associations at exposure levels that were previously considered to be without adverse effects, and these levels are common among U.S. children.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. TimothyHCiesielski@gmail.com
authors.forename: Timothy
authors.initials: T
authors.lastname: Ciesielski
authors.forename: Jennifer
authors.initials: J
authors.lastname: Weuve
authors.forename: David C
authors.initials: DC
authors.lastname: Bellinger
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Bruce
authors.initials: B
authors.lastname: Lanphear
authors.forename: Robert O
authors.initials: RO
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000139:chemically induced*; D002104:Cadmium / Q000633:toxicity* / Q000652:urine; D002648:Child; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007859:Learning Disabilities / Q000139:chemically induced*; D008297:Male; D009749:Nutrition Surveys; D014481:United States
chemical_list: D002104:Cadmium