title: Predictors and variability of repeat measurements of urinary phenols and parabens in a cohort of Shanghai women and men.
abstract: BACKGROUND
  Exposure to certain phenols is ubiquitous because of their use in many consumer and personal care products. However, predictors of exposure have not been well characterized in most populations.
  
  
  OBJECTIVE
  We sought to identify predictors of exposure and to assess the reproducibility of phenol concentrations across serial spot urine samples among Chinese adults.
  
  
  METHODS
  We measured 2,4-dichlorophenol, 2,5-dichlorophenol, butyl paraben, methyl paraben, propyl paraben, benzophenone-3, bisphenol A, and triclosan in urine collected during 1997-2006 from 50 participants of the Shanghai Women's Health Study cohort and during 2002-2006 from 50 participants of the Shanghai Men's Health Study cohort. We investigated predictors of concentrations using the Satterthwaite t-test, and assessed reproducibility among serial samples using intraclass correlation coefficients (ICCs) and Spearman correlation coefficients (SCCs).
  
  
  RESULTS
  Creatinine-corrected phenol concentrations were generally higher among women than men. Participants who had taken medicine within the previous 24 hr had higher concentrations of propyl paraben. Cigarette smoking was associated with lower concentrations of propyl and methyl parabens among men. Bottled water consumption was associated with higher bisphenol A, 2,4-dichlorophenol, and 2,5-dichlorophenol concentrations among women. Among men, reproducibility across serial samples was moderate for 2,4-dichlorophenol and 2,5-dichlorophenol (ICC = 0.54-0.60, SCC = 0.43-0.56), but lower for other analytes (ICC = 0.20-0.29). Reproducibility among women was low (ICC = 0.13-0.39), but increased when restricted to morning-only urine samples.
  
  
  CONCLUSIONS
  Among these 100 Shanghai residents, urinary phenol concentrations varied by sex, smoking, and consumption of bottled water. Our results suggest that a single urine sample may be adequate for ranking exposure to the precursors of 2,4-dichlorophenol and 2,5-dichlorophenol among men and, under certain circumstances, among women.
authors.affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, Chapel Hill, North Carolina, USA.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Engel
authors.forename: Jessie P
authors.initials: JP
authors.lastname: Buckley
authors.forename: Gong
authors.initials: G
authors.lastname: Yang
authors.forename: Linda M
authors.initials: LM
authors.lastname: Liao
authors.forename: Jaya
authors.initials: J
authors.lastname: Satagopan
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Bu-Tian
authors.initials: BT
authors.lastname: Ji
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Engel
authors.forename: Mary S
authors.initials: MS
authors.lastname: Wolff
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Rothman
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Yong-Bing
authors.initials: YB
authors.lastname: Xiang
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010226:Parabens / Q000378:metabolism; D010636:Phenols / Q000652:urine*; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D004785:Environmental Pollutants; D010226:Parabens; D010636:Phenols