Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts

Barrett M Welch; Alexander P Keil; Jessie P Buckley; Stephanie M Engel; Tamarra James-Todd; Ami R Zota; Akram N Alshawabkeh; Emily S Barrett; Michael S Bloom; Nicole R Bush; José F Cordero; Dana Dabelea; Brenda Eskenazi; Bruce P Lanphear; Vasantha Padmanabhan; Sheela Sathyanarayana; Shanna H Swan; Jenny Aalborg; Donna D Baird; Alexandra M Binder; Asa Bradman; Joseph M Braun; Antonia M Calafat; David E Cantonwine; Kate E Christenbury; Pam Factor-Litvak; Kim G Harley; Russ Hauser; Julie B Herbstman; Irva Hertz-Picciotto; Nina Holland; Anne Marie Z Jukic; Thomas F McElrath; John D Meeker; Carmen Messerlian; Karin B Michels; Roger B Newman; Ruby H N Nguyen; Katie M O'Brien; Virginia A Rauh; Bruce Redmon; David Q Rich; Emma M Rosen; Rebecca J Schmidt; Amy E Sparks; Anne P Starling; Christina Wang; Deborah J Watkins; Clarice R Weinberg; Barry Weinberger; Abby G Wenzel; Allen J Wilcox; Kimberly Yolton; Yu Zhang; Kelly K Ferguson

doi:10.1289/EHP12831

Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts

Environ Health Perspect. 2023 Dec;131(12):127015. doi: 10.1289/EHP12831. Epub 2023 Dec 20.

Authors

Barrett M Welch^{1

2}, Alexander P Keil³, Jessie P Buckley⁴, Stephanie M Engel⁵, Tamarra James-Todd⁶, Ami R Zota⁷, Akram N Alshawabkeh⁸, Emily S Barrett⁹, Michael S Bloom¹⁰, Nicole R Bush¹¹, José F Cordero¹², Dana Dabelea¹³, Brenda Eskenazi¹⁴, Bruce P Lanphear¹⁵, Vasantha Padmanabhan¹⁶, Sheela Sathyanarayana¹⁷, Shanna H Swan¹⁸, Jenny Aalborg¹³, Donna D Baird¹, Alexandra M Binder¹⁹, Asa Bradman²⁰, Joseph M Braun²¹, Antonia M Calafat²², David E Cantonwine²³, Kate E Christenbury²⁴, Pam Factor-Litvak⁷, Kim G Harley¹⁴, Russ Hauser⁶, Julie B Herbstman⁷, Irva Hertz-Picciotto²⁵, Nina Holland¹⁴, Anne Marie Z Jukic¹, Thomas F McElrath²³, John D Meeker²⁶, Carmen Messerlian⁶, Karin B Michels^{27

28}, Roger B Newman²⁹, Ruby H N Nguyen³⁰, Katie M O'Brien¹, Virginia A Rauh⁷, Bruce Redmon³¹, David Q Rich³², Emma M Rosen⁵, Rebecca J Schmidt²⁵, Amy E Sparks³³, Anne P Starling⁵, Christina Wang³⁴, Deborah J Watkins²⁶, Clarice R Weinberg¹, Barry Weinberger³⁵, Abby G Wenzel²⁹, Allen J Wilcox¹, Kimberly Yolton³⁶, Yu Zhang⁶, Kelly K Ferguson¹

Affiliations

¹ National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
² University of Nevada, Reno, Reno, Nevada, USA.
³ National Cancer Institute, Bethesda, Maryland, USA.
⁴ Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
⁵ University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
⁶ Harvard TH Chan School of Public Health, Harvard University, Boston, Massachusetts.
⁷ Columbia University Mailman School of Public Health, Columbia University, New York, New York, USA.
⁸ Northeastern University, Boston, Massachusetts, USA.
⁹ Rutgers School of Public Health, Rutgers University, Piscataway, New Jersey, USA.
¹⁰ George Mason University, Fairfax, Virginia, USA.
¹¹ University of California, San Francisco, San Francisco, California, USA.
¹² University of Georgia, Athens, Georgia, USA.
¹³ University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA.
¹⁴ Center for Environmental Research and Community Health (CERCH), University of California, Berkeley, Berkeley, California, USA.
¹⁵ Simon Fraser University, Burnaby, British Columbia, Canada.
¹⁶ University of Michigan Medical School, Ann Arbor, Michigan, USA.
¹⁷ Seattle Children's Research Institute, University of Washington, Seattle, Washington, USA.
¹⁸ Icahn School of Medicine at Mount Sinai, New York, New York, USA.
¹⁹ University of Hawai'i Cancer Center, Honolulu, Hawaii, USA.
²⁰ University of California, Merced, Merced, California, USA.
²¹ Brown University, Providence, Rhode Island, USA.
²² National Center for Environmental Health, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
²³ Brigham and Women's Hospital, Boston, Massachusetts, USA.
²⁴ Social & Scientific Systems, Inc., a DLH Holdings Company, Durham, North Carolina, USA.
²⁵ University of California, Davis, Davis, California, USA.
²⁶ School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
²⁷ University of California, Los Angeles, Los Angeles, California, USA.
²⁸ Institute for Prevention and Cancer Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany.
²⁹ Medical University of South Carolina, Charleston, South Carolina, USA.
³⁰ University of Minnesota, School of Public Health, Minneapolis, Minnesota, USA.
³¹ University of Minnesota Medical School, Minneapolis, Minnesota, USA.
³² University of Rochester Medical Center, Rochester, New York, USA.
³³ University of Iowa, Iowa City, Iowa, USA.
³⁴ The Lundquist Institute at Harbor, UCLA Medical Center, West Carson, California, USA.
³⁵ Cohen Children's Medical Center of New York, Northwell Health, Queens, New York, USA.
³⁶ Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.

Abstract

Background: Phthalate exposures are ubiquitous during pregnancy and may contribute to racial and ethnic disparities in preterm birth.

Objectives: We investigated race and ethnicity in the relationship between biomarkers of phthalate exposure and preterm birth by examining: a) how hypothetical reductions in racial and ethnic disparities in phthalate metabolites might reduce the probability of preterm birth; and b) exposure-response models stratified by race and ethnicity.

Methods: We pooled individual-level data on 6,045 pregnancies from 16 U.S. cohorts. We investigated covariate-adjusted differences in nine urinary phthalate metabolite concentrations by race and ethnicity [non-Hispanic White (White, 43%), non-Hispanic Black (Black, 13%), Hispanic/Latina (38%), and Asian/Pacific Islander (3%)]. Using g-computation, we estimated changes in the probability of preterm birth under hypothetical interventions to eliminate disparities in levels of urinary phthalate metabolites by proportionally lowering average concentrations in Black and Hispanic/Latina participants to be approximately equal to the averages in White participants. We also used race and ethnicity-stratified logistic regression to characterize associations between phthalate metabolites and preterm birth.

Results: In comparison with concentrations among White participants, adjusted mean phthalate metabolite concentrations were consistently higher among Black and Hispanic/Latina participants by 23%-148% and 4%-94%, respectively. Asian/Pacific Islander participants had metabolite levels that were similar to those of White participants. Hypothetical interventions to reduce disparities in metabolite mixtures were associated with lower probabilities of preterm birth for Black [13% relative reduction; 95% confidence interval (CI): $- 34 %$ , 8.6%] and Hispanic/Latina (9% relative reduction; 95% CI: $- 19 %$ , 0.8%) participants. Odds ratios for preterm birth in association with phthalate metabolites demonstrated heterogeneity by race and ethnicity for two individual metabolites (mono-n-butyl and monoisobutyl phthalate), with positive associations that were larger in magnitude observed among Black or Hispanic/Latina participants.

Conclusions: Phthalate metabolite concentrations differed substantially by race and ethnicity. Our results show hypothetical interventions to reduce population-level racial and ethnic disparities in biomarkers of phthalate exposure could potentially reduce the probability of preterm birth. https://doi.org/10.1289/EHP12831.

MeSH terms

Biomarkers
Ethnicity
Female
Humans
Infant, Newborn
Maternal Exposure* / adverse effects
Phthalic Acids* / adverse effects
Pregnancy
Premature Birth* / epidemiology
Racial Groups

Substances

Biomarkers
phthalic acid
Phthalic Acids

Abstract

MeSH terms

Substances

Grants and funding