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Environ Int. 2019 Nov;132:105099. doi: 10.1016/j.envint.2019.105099. Epub 2019 Aug 17.

Environmental phthalate exposure and preterm birth in the PROTECT birth cohort.

Author information

1
Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA; Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
2
Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
3
University of Puerto Rico Graduate School of Public Health, Medical Sciences Campus, San Juan, PR, USA.
4
College of Engineering, Northeastern University, Boston, MA, USA.
5
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Atlanta, GA, USA.
6
Division of Maternal-Fetal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
7
University of Puerto Rico Graduate School of Public Health, Medical Sciences Campus, San Juan, PR, USA; Department of Epidemiology and Biostatistics, University of Georgia, Athens, GA, USA.
8
Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA. Electronic address: meekerj@umich.edu.

Abstract

BACKGROUND:

Preterm birth is a global public health issue and rates in Puerto Rico are consistently among the highest in the USA. Exposures to environmental contaminants might be a contributing factor.

METHODS:

In a preliminary analysis from the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort (n = 1090), we investigated the association between urinary phthalate metabolite concentrations measured at three study visits (targeted at 20, 24, and 28 weeks of gestation) individually and averaged over pregnancy with gestational age at delivery and preterm birth. We additionally assessed differences in associations by study visit and among preterm births with a spontaneous delivery.

RESULTS:

Compared to women in the general USA population, urinary concentrations of metabolites of di-n-butyl phthalate (DBP) and di-isobutyl phthalate (DiBP) were higher among pregnant women in Puerto Rico. Interquartile range (IQR) increases in pregnancy-averages of urinary metabolites of DBP and DiBP were associated with shorter duration of gestation and increased odds of preterm birth. An IQR increase in mono-n-butyl phthalate (MBP), a metabolite of DBP, was associated with 1.55 days shorter gestation (95% confidence interval [CI] = -2.68, -0.42) and an odds ratio (OR) of 1.42 (95% confidence interval [CI]: 1.07, 1.88) for preterm birth. An IQR increase in mono-isobutyl phthalate (MiBP), a metabolite of DiBP, was associated with 1.16 days shorter gestation (95% CI = -2.25, -0.08) and an OR of 1.32 (95% CI: 1.02, 1.71) for preterm birth. Associations were greatest in magnitude for urinary concentrations measured at the second study visit (median 23 weeks gestation). DiBP metabolite associations were greatest in magnitude in models of spontaneous preterm birth. No associations were detected with other phthalate metabolites, including those of di-2-ethylhexyl phthalate.

CONCLUSION:

Among pregnant women in the PROTECT cohort, DBP and DiBP metabolites were associated with increased odds of preterm birth. These exposures may be contributing to elevated rates of preterm birth observed in Puerto Rico.

KEYWORDS:

Gestational age; Phthalates; Preterm birth; Puerto Rico; Superfund

PMID:
31430608
PMCID:
PMC6754790
[Available on 2020-11-01]
DOI:
10.1016/j.envint.2019.105099
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