Distribution, variability, and predictors of urinary bisphenol A levels in 50 North Carolina adults over a six-week monitoring period. (March 2018)

• Record Type: Journal Article
• Authors: Morgan, Marsha K.; Nash, Maliha; Barr, Dana Boyd; Starr, James M.; Scott Clifton, M.; Sobus, Jon R.
• Is Part Of: Environment international. Volume 112(2018)
• Page Start: 85
• Page End: 99
• Publication Date: 2018-03
• Subjects: BPA bisphenol-A -- BMI body mass index -- CR creatinine concentration -- EPA US Environmental Protection Agency -- Ex-R study A Pilot Study to Estimate Human Exposures to Pyrethroids using an Exposure Reconstruction Approach -- LC/MS/MS liquid chromatograph - tandem mass spectrometer -- HSF Human Studies Facility -- FMV first-morning void -- GC/MSD gas chromatograph-mass selective detector -- GM geometric mean -- ICC intraclass correlation coefficient -- LOQ limit of quantitation -- NHANES National Health and Nutritional Examination Survey -- NC North Carolina -- QC quality control -- QuEChERS quick, easy, cheap, effective, rugged, and safe method -- RTP Research Triangle Park -- SG specific gravity -- SRS surrogate recovery standard -- UPS United Parcel Service -- US United States; Bisphenol A (BPA) -- Adults -- Urine -- Homes -- Biomonitoring -- Temporal -- Determinants; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2017.12.014
• Languages: English
• ISSNs: 0160-4120

Abstract

Abstract: Bisphenol A (BPA) is commonly manufactured to make polycarbonate plastics and epoxy resins for use in consumer products and packaged goods. BPA has been found in several different types of environmental media (e.g., food, dust, and air). Many cross-sectional studies have frequently detected BPA concentrations in adult urine samples. However, limited data are available on the temporal variability and important predictors of urinary BPA concentrations in adults. In this work, the major objectives were to: 1) quantify BPA levels in duplicate-diet solid food, drinking water, hard floor surface wipe, and urine samples (first-morning void [FMV], bedtime, and 24-h) collected from adults over a six-week monitoring period; 2) determine the temporal variability of urinary BPA levels using concentration, specific gravity (SG) adjusted, creatinine (CR) adjusted, and excretion rate values, and; 3) examine associations between available study factors and urinary BPA concentrations. In 2009–2011, a convenience sample of 50 adults was recruited from residential settings in North Carolina. The participants completed diaries and collected samples during weeks 1, 2, and/or 6 of a six-week monitoring period. BPA was detected in 38%, 4%, and 99% of the solid food (n = 775), drinking water (n = 50), and surface wipe samples (n = 138), respectively. Total BPA (free plus conjugated) was detected in 98% of the 2477 urine samples. Median urinary BPA levels were 2.07 ng/mL, 2.20 ng/mL-SG, 2.29 ng/mg, and 2.31 ng/min for concentration, SG-adjusted, CR-adjusted, and excretion rate values, respectively. The intraclass correlation coefficient (ICC) estimates for BPA showed poor reproducibility (≤ 0.35) for all urine sample types and methods over a day, week, and six weeks. CR-adjusted bedtime voids collected over six-weeks required the fewest, realistic number of samples (n = 11) to obtain a reliable biomarker estimate (ICC = 0.80). Results of linear mixed-effects models showed that sex, race, season, and CR-level were all significant predictors (p < 0.05) of the adults' urinary BPA concentrations. BPA levels in the solid food and surface wipe samples did not contribute significantly to the participants' urinary BPA concentrations. However, a significant positive relationship was observed between solid food intake and urine-based estimates of BPA dose, when aggregated over 24-h periods. Ingestion of BPA via solid food explained only about 20% of the total dose (at the median of the dose distribution), suggesting that these adults were likely exposed to other major unknown (non-dietary) sources of BPA in their everyday environments. Highlights: The temporal variability and predictors of urinary BPA levels in 50 adults was assessed. ICC estimates indicate poor reproducibility (≤ 0.35) of BPA measurements in spot urine samples. Sex, race, season, and creatinine-level significantly impacted the adults' urinary BPA levels. Ingestion of BPA via solid food explained only ~ 20% of the total excreted urinary dose in Ex-R adults. Adults were likely exposed to other major (non-diet) sources of BPA in their daily environments.