title: Association of environmental chemicals & estrogen metabolites in children.
abstract: BACKGROUND
  The prevalence of pediatric hormonal disorders and hormonally-sensitive cancers are rising. Chemicals including bisphenol A (BPA), phthalates, parabens, 4-nonylphenol (4NP) and triclosan have been linked to disruption of endocrine pathways and altered hormonal status in both animal and human studies. Additionally, changes in estrogen metabolism have been associated with pediatric endocrine disorders and linked to estrogen-dependent cancers. The main objective of the study was to measure the presence of these environmental chemicals in prepubescent children and assess the relationship between chemical metabolites and estrogen metabolism.
  
  
  METHODS
  50 subjects (25 male, 25 female) were recruited from the principal investigator's existing patient population at his pediatric primary care office. The first 5 boys and 5 girls in each age group (4 through 8 years old inclusive) who presented for annual examinations were included, as long as they were Tanner Stage I (prepubertal) on physical exam, without diagnosis of hormonally-related condition and/or cancer and able to give a urine sample. Urine samples were collected in glass containers for analysis of chemical and estrogen metabolites. Study kits and lab analysis were provided by Genova Diagnostics (Duluth, GA). Summary statistics for the concentrations of each chemical metabolite as well as estrogen metabolites were computed (minimum, maximum, median and inter-quartile range) for males only, for females only and for all subjects. Comparisons between groups (e.g. males v. females) were assessed using the nonparametric Wilcoxon test, since the data was skewed. The correlation between concentrations of chemical metabolites and estrogen metabolites in prepubescent children were examined by the Spearman's correlation coefficient (ρ).
  
  
  RESULTS
  100 % of subjects had detectable levels of at least five chemicals [corrected] in their urine, and 74 % had detectable levels of eight or more chemicals. 28 % of subjects had measurable levels of 4NP. No associations were found between the urine levels of chemicals and estrogen metabolites.
  
  
  CONCLUSIONS
  Endocrine disrupting environmental chemicals were detected in all children in the study, with measurable levels of 4NP in nearly 1/3 of subjects. This is the first known published study of 4NP levels in American children. No associations were found between the urine levels of chemicals tested and estrogen metabolites. The presence of multiple chemicals in a majority of children's urine coupled with increasing prevalence of pediatric hormonal disorders warrants further research to elucidate potential causal mechanisms in pre- and post-pubertal children.
authors.affiliation: The Deirdre Imus Environmental Health Center®, Hackensack University Medical Center, 30 Prospect Ave, Research Building, Hackensack, NJ, 07601, USA. eihde@HackensackUMC.org.
authors.forename: Erin Speiser
authors.initials: ES
authors.lastname: Ihde
authors.affiliation: Department of Mathematical Sciences, NJ Institute of Technology, University Heights, Newark, NJ, 07102, USA. loh@njit.edu.
authors.forename: Ji Meng
authors.initials: JM
authors.lastname: Loh
authors.affiliation: The Deirdre Imus Environmental Health Center®, Hackensack University Medical Center, 30 Prospect Ave, Research Building, Hackensack, NJ, 07601, USA. lrosen@wholechildcenter.org.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Rosen
mesh_terms: D001559:Benzhydryl Compounds / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002648:Child; D052244:Endocrine Disruptors / Q000009:adverse effects*; D004701:Endocrine Gland Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000517:prevention & control; D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D010226:Parabens / Q000633:toxicity; D010636:Phenols / Q000652:urine; D010795:Phthalic Acids / Q000652:urine; D014260:Triclosan / Q000652:urine; D014481:United States / Q000453:epidemiology; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D015415:Biomarkers; D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D010226:Parabens; D010636:Phenols; D010795:Phthalic Acids; D014260:Triclosan; C006780:bisphenol A; D000098826:Bisphenol A Compounds