title: Brominated Flame Retardants and Other Persistent Organohalogenated Compounds in Relation to Timing of Puberty in a Longitudinal Study of Girls.
abstract: BACKGROUND
  Exposure to hormonally active chemicals could plausibly affect pubertal timing, so we are investigating this in the Breast Cancer and the Environment Research Program.
  
  
  OBJECTIVE
  Our goal was to examine persistent organic pollutants (POPs) in relation to pubertal onset.
  
  
  METHODS
  Ethnically diverse cohorts of 6- to 8-year-old girls (n = 645) provided serum for measure of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and lipids. Tanner stages [breast (B) and pubic hair (PH)], and body mass index (BMI) were measured at up to seven annual clinic visits. Using accelerated failure time models, we calculated time ratios (TRs) for age at Tanner stages 2 or higher (2+) and POPs quartiles (Q1-4), adjusting for confounders (race/ethnicity, site, caregiver education, and income). We also calculated prevalence ratios (PRs) of Tanner stages 2+ at time of blood sampling.
  
  
  RESULTS
  Cross-sectionally, the prevalence of B2+ and PH2+ was inversely related to chemical serum concentrations; but after adjustment for confounders, only the associations with B2+, not PH2+, were statistically significant. Longitudinally, the age at pubertal transition was consistently older with greater chemical concentrations; for example: adjusted TR for B2+ and Q4 for ΣPBDE = 1.05; 95% CI: 1.02, 1.08, for ΣPCB = 1.05; 95% CI: 1.01, 1.08, and for ΣOCP = 1.10; 95% CI: 1.06, 1.14, indicating median ages of about 6 and 11 months older than least exposed, and with similar effect estimates for PH2+. Adjusting for BMI attenuated associations for PCBs and OCPs but not for PBDEs.
  
  
  CONCLUSIONS
  This first longitudinal study of puberty in girls with serum POPs measurements (to our knowledge) reveals a delay in onset with higher concentrations.
authors.affiliation: California Department of Public Health, Richmond, California, USA.
authors.forename: Gayle C
authors.initials: GC
authors.lastname: Windham
authors.forename: Susan M
authors.initials: SM
authors.lastname: Pinney
authors.forename: Robert W
authors.initials: RW
authors.lastname: Voss
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjödin
authors.forename: Frank M
authors.initials: FM
authors.lastname: Biro
authors.forename: Louise C
authors.initials: LC
authors.lastname: Greenspan
authors.forename: Susan
authors.initials: S
authors.lastname: Stewart
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hiatt
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Kushi
mesh_terms: D001940:Breast / Q000187:drug effects / Q000254:growth & development; D002140:California; D002648:Child; D052244:Endocrine Disruptors / Q000097:blood; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D005411:Flame Retardants / Q000032:analysis; D006197:Hair / Q000187:drug effects / Q000254:growth & development; D055768:Halogenated Diphenyl Ethers / Q000097:blood*; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D008137:Longitudinal Studies; D009820:Ohio; D010575:Pesticides / Q000097:blood; D011078:Polychlorinated Biphenyls / Q000097:blood; D011627:Puberty / Q000187:drug effects*
chemical_list: D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D011078:Polychlorinated Biphenyls