title: Variability and predictors of urinary bisphenol A concentrations during pregnancy.
abstract: BACKGROUND
  Prenatal bisphenol A (BPA) exposure may be associated with developmental toxicity, but few studies have examined the variability and predictors of urinary BPA concentrations during pregnancy.
  
  
  OBJECTIVE
  Our goal was to estimate the variability and predictors of serial urinary BPA concentrations taken during pregnancy.
  
  
  METHODS
  We measured BPA concentrations during pregnancy and at birth in three spot urine samples from 389 women. We calculated the intraclass correlation coefficient (ICC) to assess BPA variability and estimated associations between log10-transformed urinary BPA concentrations and demographic, occupational, dietary, and environmental factors, using mixed models.
  
  
  RESULTS
  Geometric mean (GM) creatinine-standardized concentrations (micrograms per gram) were 1.7 (16 weeks), 2.0 (26 weeks), and 2.0 (birth). Creatinine-standardized BPA concentrations exhibited low reproducibility (ICC = 0.11). By occupation, cashiers had the highest BPA concentrations (GM: 2.8 μg/g). Consuming canned vegetables at least once a day was associated with higher BPA concentrations (GM = 2.3 μg/g) compared with those consuming no canned vegetables (GM = 1.6 μg/g). BPA concentrations did not vary by consumption of fresh fruits and vegetables, canned fruit, or store-bought fresh and frozen fish. Urinary high-molecular-weight phthalate and serum tobacco smoke metabolite concentrations were positively associated with BPA concentrations.
  
  
  CONCLUSIONS
  These results suggest numerous sources of BPA exposure during pregnancy. Etiological studies may need to measure urinary BPA concentrations more than once during pregnancy and adjust for phthalates and tobacco smoke exposures.
authors.affiliation: Department of Environmental Health, Harvard University, Boston, Massachusetts, USA. jbraun@hsph.harvard.edu
authors.forename: Joe M
authors.initials: JM
authors.lastname: Braun
authors.forename: Amy E
authors.initials: AE
authors.lastname: Kalkbrenner
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
authors.forename: John T
authors.initials: JT
authors.lastname: Bernert
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Ye
authors.forename: Manori J
authors.initials: MJ
authors.lastname: Silva
authors.forename: Dana Boyd
authors.initials: DB
authors.lastname: Barr
authors.forename: Sheela
authors.initials: S
authors.lastname: Sathyanarayana
authors.forename: Bruce P
authors.initials: BP
authors.lastname: Lanphear
mesh_terms: D000328:Adult; D001559:Benzhydryl Compounds; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine; D003710:Demography; D004032:Diet / Q000706:statistics & numerical data; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D005506:Food Contamination; D018857:Food Packaging; D006801:Humans; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D010636:Phenols / Q000652:urine*; D010795:Phthalic Acids / Q000652:urine; D011247:Pregnancy; D012959:Socioeconomic Factors; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D015415:Biomarkers; D003404:Creatinine; D004785:Environmental Pollutants; D010636:Phenols; D010795:Phthalic Acids; C032279:phthalic acid; C006780:bisphenol A; D000098826:Bisphenol A Compounds