Food System Contributions to Bisphenol-A Exposures

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Johns Hopkins University
This dissertation explores the food system’s contributions to bisphenol-A (BPA) exposures through an analysis of dietary data, modeling of the potential BPA exposure from school meals, and a review of food contact materials policies. Its discoveries enhance the epidemiologic work examining sources of bisphenol A exposures from the food system to inform and improve policy. Data from NHANES 2003-2008 were utilized to identify dietary contributions associated with the presence of bisphenol-A in humans. Statistical analysis modeled relationships between urinary BPA concentrations and consumption of canned food and beverages, as identified by 24-hour dietary recall, accounting for demographic and socioeconomic factors. In addition, factor analysis methods were conducted to discover dietary patterns associated with higher urinary BPA concentrations. The regression models revealed a statistically significant increase in urinary BPA concentration with greater consumption of canned food, and specifically canned pasta, vegetables, and beans. The exploratory factor analysis revealed that the dietary patterns of the population with the highest urinary BPA concentrations differed from the other population categories explored, giving evidence that specific food groups could be contributing to higher BPA exposures. The school meal exposure models forecasted potential daily doses of bisphenol-A from a typical school breakfast and lunch based on different exposure scenarios. Values ranged from 7.7 x 10-4 mg/kg-BW/day to 0.97 mg/ kg-BW/day. The modeled BPA exposure doses are low in comparison to the BPA RfD of 50 mg/kg-BW/day determined by the EPA to be a safe chronic exposure level. Newer research performed since the RfD was established demonstrates that the threshold for animal toxicity to BPA is as low as 0.025 mg/kg-BW/day. Many of the doses modeled exceed this toxicity threshold, illustrating the potential for school meals to place children at risk for toxic exposures of BPA. This research confirmed the need for more investigations of BPA in institutional food. Efforts should focus on laboratory analysis for BPA in foods unique to schools, such as institutional sized cans, bulk bags of frozen, pre-cooked proteins, and individually wrapped foods. Additional research should quantify the transfer of BPA from food preparation and service activities.
School lunch, Canned food, NHANES, Diet, Exposure assessment, Dietary assessment, Dose, Policy, Exposure modeling, School nutrition, Packaged food, Bisphenol-A, Children, Food systems, BPA