Measurement of Total and Free Urinary Phenol and Paraben Concentrations over the Course of Pregnancy: Assessing Reliability and Contamination of Specimens in the Norwegian Mother and Child Cohort Study
Background: Exposures to environmental phenols and parabens may be harmful, especially in utero. Prior studies have demonstrated high within-person variability of urinary concentrations across pregnancy.
Objectives: We sought to measure phenol and paraben biomarker concentrations for the Norwegian Mother and Child Cohort (MoBa) study, assess within-person variability, and investigate any possible external phenol or paraben contamination of specimens.
Methods: We collected three spot urine samples at approximately 17, 23, and 29 weeks gestation in a hospital setting and added a preservative containing ethyl paraben. We measured urinary concentrations and within-person variability for phenols and parabens in a MoBa sample (n = 45), including a subgroup of 15 participants previously randomly selected for a bisphenol A (BPA) exposure study who had unusually high total BPA concentrations. Additionally, we compared reliability results for total, conjugated, and free concentrations of phenolic compounds.
Results: We detected total and free BPA, butyl paraben, propyl paraben, and methyl paraben in 100% of samples, total benzophenone-3 in 95% of samples, and infrequently detected free benzophenone-3 and total and free 2,4-dichlorophenol and 2,5-dichlorophenol. Intraclass correlation coefficients (ICCs) for total, conjugated, and free concentrations ranged from relatively low for BPA to moderate for propyl paraben. ICCs were generally similar overall and by subgroup.
Conclusions: Using conjugated concentrations improved reliability estimates only for BPA. Measuring total and free concentrations, an approach that may be useful for future studies, allowed us to identify likely BPA and butyl paraben contamination of archived MoBa urine specimens.
1Department of Epidemiology, UNC Gillings School of Global Public Health, Chapel Hill, North Carolina, USA; 2Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA; 3Department of Child Development and Mental Health, and 4Department of Genes and Environment, Norwegian Institute of Public Health, Oslo, Norway; 5Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway; 6Department of Genetics, Environment and Mental Health, Norwegian Institute of Public Health, Oslo, Norway; 7Haukeland University Hospital, Department of Occupational Medicine, Bergen, Norway; 8Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Recommended Citation:
Virginia T. Guidry,1 Matthew P. Longnecker,2 Heidi Aase,et al. Measurement of Total and Free Urinary Phenol and Paraben Concentrations over the Course of Pregnancy: Assessing Reliability and Contamination of Specimens in the Norwegian Mother and Child Cohort Study[J]. Environmental Health Perspectives,2015-01-01,Volume 123(Issue 7):705