Exposure to free and conjugated forms of bisphenol A and triclosan among pregnant women in the MIREC cohort
- DOI
- Language of the publication
- English
- Date
- 2014-11-21
- Type
- Article
- Author(s)
- Arbuckle, Tye E.
- Marro, Leonora
- Davis, Karelyn
- Fisher, Mandy
- Ayotte, Pierre
- Bélanger, Patrick
- Dumas, Pierre
- LeBlanc, Alain
- Bérubé, René
- Gaudreau, Éric
- Provencher, Gilles
- Faustman, Elaine M.
- Vigoren, Eric
- Ettinger, Adrienne S.
- Dellarco, Michael
- MacPherson, Susan
- Fraser, William D.
- Publisher
- National Institute of Environmental Health Sciences
Abstract
Background: Bisphenol A (BPA) and triclosan (TCS) are two nonpersistent chemicals that have been frequently measured in spot urine samples from the general population but less so in pregnant women; however, data are limited on the free (bioactive) and conjugated forms of these phenols. Objectives: The Maternal-Infant Research on Environmental Chemicals (MIREC) Study addressed these data gaps by utilizing stored maternal urine samples from a large multicenter cohort study of Canadian pregnant women. Methods: Concentrations of free and conjugated forms of BPA and TCS were measured in about 1,890 first-trimester urine samples by ultra performance liquid chromatography-tandem mass spectrometry using isotope dilution. Results: The glucuronides of BPA and TCS were the predominant forms of these chemicals measured (detected in 95% and 99% of samples, respectively), whereas the free forms were detected in 43% and 80% of samples, respectively. The geometric mean urinary concentrations for glucuronides of BPA and TCS were 0.80 μg/L (95% CI: 0.75, 0.85) and 12.30 μg/L (95% CI: 11.08, 13.65), respectively. Significant predictors of BPA included maternal age < 25 vs. ≥ 35 years, current smoking, low vs. high household income, and low vs. high education. For TCS, urinary concentrations were significantly higher in women ≥ 25 years of age, never vs. current smokers, and women with high household income and high education. Conclusions: The results from this study represent the largest national-level data on urinary concentrations of free and conjugated forms of BPA and TCS in pregnant women and suggest that maternal characteristics predicting elevated urinary concentrations of these phenols largely act in opposite directions.
Plain language summary
Health Canada has the responsibility to assess the health risks to Canadians associated with exposure to chemicals in the environment. The Maternal-Infant Research on Environmental Chemicals (MIREC) study was designed to measure exposure to and any potential health effects of elevated levels of environmental chemicals during pregnancy. Two of the chemicals for which there are limited data on levels in pregnant women are triclosan and bisphenol A (BPA). Triclosan is used as an antimicrobial in a wide range of cosmetics and personal care products, including non-prescription drugs. BPA is used to make a hard, clear plastic and may also be found in epoxy resin linings on the inside of metal-based food and beverage cans. Thermal papers such as receipts and tickets may also be a source of BPA. In this study, Health Canada undertook to measure these two chemicals in a urine sample from approximately 1,900 pregnant women participating in the MIREC Study. BPA levels were higher in women with a lower household income, under 25 years of age or in smokers. Triclosan levels tended to be higher in women who had never smoked or were 25 years of age or older. Health Canada will use the results of this study to estimate exposure to these chemicals for the Canadian population.
Subject
- Health,
- Health and safety