Abstract
BackgroundBisphenol A (BPA) is a ubiquitous, endocrine-disrupting environmental contaminant that increases risk of some adverse developmental effects. Thus, it is important to characterize BPA levels, metabolic fate and sources of exposure in pregnant women.MethodsWe used an improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytic method to directly and simultaneously measure unconjugated BPA (uBPA), BPA glucuronide and BPA sulfate in the urine of a population of ethnically and racially diverse, and predominately low-income pregnant women (n = 112) in their second trimester. We also administered a questionnaire on dietary and non-dietary sources of exposure to BPA.ResultsWe found universal and high exposure to uBPA and its metabolites: median concentrations were 0.25, 4.67, and 0.31 μg/g creatinine for uBPA, BPA glucuronide, and BPA sulfate, respectively. The median Total BPA (uBPA + BPA in glucuronide and sulfate forms) level was more than twice that measured in U.S. pregnant women in NHANES 2005–2006, while 30 % of the women had Total BPA levels above the 95th percentile. On average, Total BPA consisted of 71 % BPA in glucuronide form, 15 % BPA in sulfate form and 14 % uBPA, however the proportion of BPA in sulfate form increased and the proportion of uBPA decreased with Total BPA levels. Occupational and non-occupational contact with paper receipts was positively associated with BPA in conjugated (glucuronidated + sulfated) form after adjustment for demographic characteristics. Recent consumption of foods and beverages likely to be contaminated with BPA was infrequent among participants and we did not observe any positive associations with BPA analyte levels.ConclusionThe high levels of BPA analytes found in our study population may be attributable to the low-income status of the majority of participants and/or our direct analytic method, which yields a more complete evaluation of BPA exposure. We observed near-universal exposure to BPA among pregnant women, as well as substantial variability in BPA metabolic clearance, raising additional concerns for effects on fetal development. Our results are consistent with studies showing thermal paper receipts to be an important source of exposure, point to the difficulty pregnant women have avoiding BPA exposure on an individual level, and therefore underscore the need for changes in BPA regulation and commerce.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0131-2) contains supplementary material, which is available to authorized users.
Highlights
Bisphenol A (BPA) is a ubiquitous, endocrine-disrupting environmental contaminant that increases risk of some adverse developmental effects
Our results are consistent with studies showing thermal paper receipts to be an important source of exposure, point to the difficulty pregnant women have avoiding BPA exposure on an individual level, and underscore the need for changes in BPA regulation and commerce
Concentrations of BPA in glucuronide form were higher than other BPA forms in 85 % of urine samples, whereas BPA in sulfate form was higher than other BPA forms in 5 % of participants who had higher Total BPA levels (GM = 5.7 vs. 19.4 ng/g, Kruskall Wallis p = 0.07)
Summary
Bisphenol A (BPA) is a ubiquitous, endocrine-disrupting environmental contaminant that increases risk of some adverse developmental effects. Epidemiology studies have found associations between BPA exposure and adverse reproductive health effects, such as reduced semen quality, sperm DNA damage [17,18,19] and oocyte maturity and normal fertilization in women undergoing IVF [20]. BPA continues to be produced and used in consumer products in large quantities (averaging 8 lb per capita in the United States with a total of 2.3 billion pounds annually [3, 21]), resulting in ubiquitous human exposure: more than 90 % of the general and 96 % of the pregnant U.S population have measurable levels of Total BPA (unconjugated BPA (uBPA) plus its primary conjugated metabolites, BPA glucuronide and BPA sulfate) in their urine [3, 22, 23]. Higher urinary levels of Total BPA have been measured in lower socioeconomic status U.S women and children, and lower levels in U.S Hispanic women and children, suggesting BPA exposure varies by race/ethnicity, sex and age [23,24,25]
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