A comprehensive analysis of racial disparities in chemical exposure biomarkers in US women

Abstract

PDS 64: Health impact assessment and environmental justice, Johan Friso Foyer, Floor 1, August 26, 2019, 1:30 PM - 3:00 PM Background: African American women are 2 to 3 times more likely to be diagnosed with triple negative breast cancer, compared to European American women. The biological mechanisms for this disparity are not well understood but are likely due to an interaction between genes and environmental exposures. To better understand environmental factors which may impact triple negative breast cancer risk, we implemented an untargeted approach to systematically compare chemical exposure differences by race. Methods: We used the National Health and Nutrition Examination Survey (NHANES) of 148 chemical biomarker concentrations measured in 38,080 female participants 1999-2014. We conducted a series of multiple survey weighted regression models with chemical biomarker levels as the outcome variable and race/ethnicity as the main predictor while adjusting for age, cotinine levels (biomarker of smoking), poverty-income ratio (surrogate variable of socioeconomic status), and cycles (years) in which the participants were sampled. To understand chemical exposures by age and race, we conducted stratified analyses by age groups (0-11, 12-25, 26-50, and 51-up). Results: Across age groups, African American women had significantly higher biomarker concentrations of many chemicals, including methyl paraben (2.39-fold), propyl paraben (2.09-fold), mono-ethyl phthalate (1.74-fold), 1,4-Dichlorobenzene (2.35), and 2,5-dichlorophenol (4.56-fold), relative to non-Hispanic white women. For the youngest age group (0-11 years), the chemical exposure disparities between African American and non-Hispanic white women are further exaggerated for parabens and 1-4 dichlorobenzene. Conclusions: Overall, we identified substantial differences in chemical body burden by race in a representative sample of US women. Many of the chemicals with exposure disparities are found in cosmetics, pesticides, and other consumer products. Ongoing work is determining whether these toxicants impact biological pathways associated with breast cancer to better understand the link between the environment and triple negative breast cancer disparities.