Temporal trends in bisphenol A exposure in the United States from 2003–2012 and factors associated with BPA exposure: Spot samples and urine dilution complicate data interpretation

Abstract

Nationally representative data on urinary levels of BPA and its metabolites in the United States from the 2003-2004 to 2011-2012 National Health and Nutrition Examination Surveys (NHANES) were used to estimate daily BPA intakes and examine temporal trends. Additionally, NHANES data on lifestyle/demographic/dietary factors previously reported to be associated with BPA exposures were examined to assess the resiliency of the reported associations (whether the association is maintained across the five surveys). Finally, various approaches for addressing issues with the use of BPA concentration data from spot urine samples were examined for their effect on trends and associations. Three approaches were assessed here: (i) use of generic literature-based 24-h urine excretion volumes, (ii) use of creatinine adjustments, and (iii) use of individual urine flow rate data from NHANES. Based on 2011-2012 NHANES urinary BPA data and assumptions described in this paper, the median daily intake for the overall population is approximately 25 ng/kg day; median intake estimates were approximately two to three orders of magnitude below current health-based guidance values. Estimates of daily BPA intake have decreased significantly compared to those from the 2003-2004 NHANES. Estimates of associations between lifestyle/demographic/dietary factors and BPA exposure revealed inconsistencies related to both NHANES survey year and the three approaches listed above; these results demonstrate the difficulties in interpreting urinary BPA data, despite efforts to account for urine dilution and translation of spot sample data to 24-h data. The results further underscore the importance of continued research on how to best utilize urinary measures of environmental chemicals in exposure research. Until a consensus is achieved regarding the best biomonitoring approaches for assessing exposures to short-lived chemicals using urine samples, research on factors associated with BPA exposures should include - and report results from - assessments using both volume-based urinary BPA and creatinine-adjusted urinary BPA data.

The consumption of canned food and beverages and urinary Bisphenol A concentrations in NHANES 2003–2008

“…By January 2010, FDA had released a report expressing “some concern” for BPA in children’s products and cans. As BPA was being removed from packaging, there was an increase in the use of alternative bisphenols such as Bisphenol F (BPF) and Bisphenol S (BPS) that could be measured in humans (LaKind and Naiman 2015; Liao and Kannan 2013; Ye et al 2015). Overall, the largest changes in BPA applications were in infant and toddler products, products not used by our sampled population of six years and older, with the official legislation to remove the use approval for BPA in PC baby bottles and sippy cups and in infant formula packaging occurring in 2012 and 2013 (FDA 2012, 2013).…”

“…Because of its rapid clearance from the body through urine, total urinary BPA compounds, comprised of free plus conjugated BPA, are the most appropriate BPA exposure assessment marker (Melzer et al 2010). The best urinary collection method including single samples vs. 24-hour sampling, and the timing of sampling have been investigated (Arakawa et al 2004; Christensen et al 2012; Dekant and Volkel 2008; LaKind and Naiman 2015; Lassen et al 2013; Mahalingaiah et al 2008; Ye et al 2011). The conclusions of those studies vary depending on a researcher’s intent to determine individual or population level BPA exposures and short-term vs. long term exposure profiles.…”

Effects of perinatal bisphenol A exposure on the volume of sexually-dimorphic nuclei of juvenile rats: A CLARITY-BPA consortium study

“…Human exposure to BPA is virtually unavoidable and occurs primarily from contaminated food and beverages. In industrialized countries, well over 90% of individuals are estimated to have detectable amounts of BPA in their bodies, albeit in small amounts (serum levels are typically in the range of 4 ng/ml or lower) (Bushnik et al, 2010; Calafat et al, 2005; Calafat et al, 2008; Casas et al, 2013; LaKind and Naiman, 2015). The most significant route of human exposure is thought to be ingestion, with dietary intake estimated to range from 0.1 – 1.4 µg/kg body weight (bw)/day, but exposure can also occur from other sources (FAO/WHO, 2011).…”

Infant Exposure to Bisphenol A Can Be Quantitatively Assessed by a Simply Improved High-Performance Liquid Chromatography–Tandem Mass-Spectrometry Method

“…The estimated daily BPA intake has decreased significantly from 2003 -2004 to 2011 -2012, 17,22 but high levels of BPA can still be observed in some infant urine samples. 18 The distinct exposure differences may be because of the different life style, age and regional different BPA usage.…”

“…[11][12][13][14][15][16] For example, the National Health and Nutrition Examination Survey (NHANES) 2015 reported that more than 90% of urine samples from participants >6 years old can detect BPA with a median of 2.7 μg/L in 2003 -2004 and 1.4 μg/L in 2011 -2012. 17 However, only a few reports have shown that infant cohorts were exposed to BPA. For example, one study reported that the investigated infant (3 -15 months old) urine samples had a mean of 0.96 μg/L BPA, 18 few other reports [19][20][21][22] also showed that the newborn and/or young infant urine indicated trace levels of BPA being detected.…”