title: Association Between Urinary Phthalates and Pubertal Timing in Chinese Adolescents.
abstract: BACKGROUND
  Phthalates are synthetic chemicals and ubiquitous environmental contaminants, with hormonal activity that may alter the course of pubertal development in children.
  
  
  OBJECTIVE
  To determine whether exposure to phthalate metabolites is associated with timing of pubertal development in a cross-sectional study of a school-based clustered sample of 503 children from a suburban district in Shanghai, China, who were 7-14 years of age at enrollment (2010 October to November).
  
  
  METHODS
  We analyzed six phthalate metabolites in urine samples by isotope-dilution liquid chromatography tandem mass spectrometry. The associations of exposures to phthalates with pubertal timing of testes, breast, and pubic hair development (represented as Tanner stages) were evaluated using an ordered logistic regression model adjusted for chronological age, body fat proportion (BF%), and parental education.
  
  
  RESULTS
  In boys, urinary mono-n-butyl phthalate (MBP) levels were negatively associated with testicular volume, and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) levels were negatively associated with pubic hair stages. The odds of being in an advanced stage were decreased by 43%-51%. In girls, mono (2-ethylhexyl) phthalate (MEHP), MEHHP, and MEOHP levels, as well as the sum of these levels, were positively associated with breast stages, and the association was much stronger in girls with high BF%; the odds of being in an advanced stage were increase by 29% to 50%.
  
  
  CONCLUSIONS
  Phthalate metabolites investigated in this study show significant associations with pubertal timing both in boys and in girls, especially among girls with high BF%.
authors.affiliation: School of Public Health, Fudan University & Key Laboratory of Public Health Safety, Chinese Ministry of Education.
authors.forename: Huijing
authors.initials: H
authors.lastname: Shi
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
authors.forename: Qing
authors.initials: Q
authors.lastname: Shen
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000032:analysis; D004785:Environmental Pollutants / Q000009:adverse effects / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010795:Phthalic Acids / Q000009:adverse effects / Q000378:metabolism* / Q000652:urine; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012741:Sexual Maturation / Q000187:drug effects*; D013997:Time Factors
chemical_list: D004785:Environmental Pollutants; D010795:Phthalic Acids; C032279:phthalic acid