Racial and ethnic differences in prenatal exposure to environmental phenols and parabens in the ECHO Cohort

Abstract

Background: Research suggests racial/ethnic disparities in prenatal exposure to endocrine disrupting environmental phenols (EPs) in limited populations. However, no studies have investigated racial/ethnic disparities in prenatal EP exposure across the U.S.

Objectives: To estimate demographic differences in prenatal urinary EPs among participants in the Environmental influences on Child Health Outcomes (ECHO) Cohort.

Methods: An analysis of 4006 pregnant ECHO participants was performed, with 7854 specimens collected from 1999-2020. Racial/ethnic identity was self-reported. Urinary levels of 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), benzophenone-3 (BP-3), bisphenols A (BPA), F (BPF), and S (BPS), and methyl- (MePb), ethyl- (EtPb), propyl- (PrPb), and butyl- (BuPb) parabens were measured at one or more time points during pregnancy. Effect estimates were adjusted for age, pre-pregnancy body mass index, educational level, gestational age and season at urine collection, and ECHO cohort.

Results: Participants were classified as Hispanic of any race (n = 1658), non-Hispanic White (n = 1478), non-Hispanic Black (n = 490), and non-Hispanic Other (n = 362), which included individuals of multiple races. Urinary 2,4-DCP and 2,5-DCP concentrations were 2- to 4-fold higher among Hispanic, non-Hispanic Black, and non-Hispanic Other participants relative to non-Hispanic White participants. MePb was ~2-fold higher among non-Hispanic Black (95% confidence interval (CI): 1.7-3.1) and non-Hispanic Other (95% CI: 1.5-2.8) participants. PrPb was similarly higher among non-Hispanic Black (95% CI: 1.7-3.7) and non-Hispanic Other (95% CI: 1.3-3.1) participants. EtPb was higher among non-Hispanic Black participants (3.1-fold; 95% CI 1.7-5.8). BP-3 was lower in Hispanic (0.7-fold; 95% CI: 0.5-0.9), non-Hispanic Black (0.4-fold; 95% CI: 0.3-0.5), and non-Hispanic Other (0.5-fold; 95% CI: 0.4-0.7) participants. Urinary BuPb, BPA, BPF, and BPS were similar across groups.

Impact statement: This multisite, observational cohort study investigated whether there are racial and ethnic differences in prenatal exposure to endocrine disrupting environmental phenols and parabens. Among 4006 participants from multiple U.S. cohorts who provided urine specimens during pregnancy, those who self-reported a racial and ethnic identity other than non-Hispanic White had higher urinary concentrations of 2,4-dichlorophenol, 2,5-dichlorophenol, methyl paraben, ethyl paraben, and propyl paraben and lower urinary concentrations of benzophenone-3 than those reporting as non-Hispanic White. These data show differences in prenatal concentrations of endocrine disrupting environmental phenols and parabens by racial and ethnic identity.

Keywords: Environmental phenols; Ethnicity; Health inequities; Parabens; Pregnancy.

Fig. 1. Distributions of natural log-transformed urinary chemical concentrations among pregnant ECHO participants by self-reported racial and ethnic identity.

Urinary phenol concentrations (µg/L) corrected for urinary specific gravity or urinary creatinine. Abbreviations: ECHO Environmental influences on Child Health Outcomes, Mult/Oth/Asian non-Hispanic multiple races, “Other,” and Asian.

Fig. 2. Covariate-adjusted associations between self-reported racial and ethnic identity and urinary chemical concentrations (µg/L) among pregnant ECHO participants.

Effect estimates are ratios of geometric means and 95% confidence intervals from individual linear mixed effect censored-response regression models of specific gravity/creatinine-corrected urinary phenol concentrations as outcomes and maternal racial and ethnic identity categories as predictors (non-Hispanic White = reference category), a random intercept on pregnancy to account for multiple urinary measurements and adjusted for maternal age (years), pre-pregnancy body mass index (kg/m²), educational level (completed vs. did not complete bachelor’s degree), gestational age at biospecimen collection (weeks), season of biospecimen collection (fall vs. winter vs. spring vs. summer), and ECHO study cohort (11 cohorts). Abbreviations: BPA bisphenol A, BPF bisphenol F, BPS bisphenol S, ECHO Environmental Influences on Child Health Outcomes, Mult/Oth/Asian non-Hispanic multiple races, “Other,” and Asian.