Cross-sectional associations between prenatal maternal per- and poly-fluoroalkyl substances and bioactive lipids in three Environmental influences on Child Health Outcomes (ECHO) cohorts.

Background: Per- and poly-fluoroalkyl substances (PFAS) exposure can occur through ingestion of contaminated food and water, and inhalation of indoor air contaminated with these chemicals from consumer and industrial products. Prenatal PFAS exposures may confer risk for pregnancy-related outcomes such as hypertensive and metabolic disorders, preterm birth, and impaired fetal development through intermediate metabolic and inflammation pathways. Objective: Estimate associations between maternal pregnancy PFAS exposure (individually and as a mixture) and bioactive lipids. Methods: Our study included pregnant women in the Environmental influences on Child Health Outcomes Program: Chemicals in our Bodies cohort (CiOB, n=73), Illinois Kids Developmental Study (IKIDS, n=287), and the ECHO-PROTECT cohort (n=54). We measured twelve PFAS in serum and 50 plasma bioactive lipids (parent fatty acids and eicosanoids derived from cytochrome p450, lipoxygenase, and cyclooxygenase) during pregnancy (median 17 gestational weeks). Pairwise associations across cohorts were estimated using linear mixed models and meta-analysis. Associations between the PFAS mixture and individual bioactive lipids were estimated using quantile g-computation. Results: PFDeA, PFOA, and PFUdA were associated (p<0.05) with changes in bioactive lipid levels in all three enzymatic pathways (cyclooxygenase [n=6 signatures]; cytochrome p450 [n=5 signatures]; lipoxygenase [n=7 signatures]) in at least one combined cohort analysis. The strongest signature indicated that a doubling in PFOA corresponded with a 24.3% increase (95% CI [7.3%, 43.9%]) in PGD2 (cyclooxygenase pathway) in the combined cohort. In the mixtures analysis, we observed nine positive signals across all pathways associated with the PFAS mixture. The strongest signature indicated that a quartile increase in the PFAS mixture was associated with a 34% increase in PGD2 (95% CI [8%, 66%]), with PFOS contributing most to the increase. Conclusions: Bioactive lipids were revealed as biomarkers of PFAS exposure and could provide mechanistic insights into PFAS' influence on pregnancy outcomes, informing more precise risk estimation and prevention strategies.

Biomarkers of Exposure to Phthalate Mixtures and Adverse Birth Outcomes in a Puerto Rico Birth Cohort.

BACKGROUND: Humans are exposed to complex mixtures of phthalate chemicals from a range of consumer products. Previous studies have reported significant associations between individual phthalate metabolites and pregnancy outcomes, but mixtures research is limited. OBJECTIVES: We used the Puerto Rico Testsite for Exploring Contamination Threats longitudinal pregnancy cohort to investigate associations between phthalate metabolite mixtures and pregnancy outcomes. METHODS: Women (n=462 carrying females, n=540 carrying males) provided up to three urine samples throughout gestation (median 18, 22, and 26 wk), which were analyzed for 13 phthalate metabolites. Pregnancy outcomes including preterm birth (PTB), spontaneous PTB, small and large for gestational age (SGA, LGA), birth weight z-score, and gestational age at delivery were abstracted from medical records. Environmental risk scores (ERS) were calculated as a weighted linear combination of the phthalates from ridge regression and adaptive elastic net, which are variable selection methods to handle correlated predictors. Birth outcomes were regressed on continuous ERS. We assessed gestational average and visit-specific ERS and stratified all analyses by fetal sex. Finally, we used Bayesian kernel machine regression (BKMR) to explore nonlinear associations and interactions between metabolites. RESULTS: Differences in metabolite weights from ridge and elastic net were apparent between birth outcomes and between fetal sexes. An interquartile range increase in gestational average phthalate ERS was associated with increased odds of PTB [male odds ratio (OR)=1.56; 95% confidence interval (CI): 1.08, 2.27; female OR=1.91; 95% CI: 1.23, 2.98], spontaneous PTB (male OR=2.32; 95% CI: 1.46, 3.68; female OR=2.00; 95% CI: 1.04, 3.82), and reduced gestational age at birth (male ß=-0.39 wk, 95% CI: -0.62, -0.15; female ß=-0.29 wk, 95% CI: -0.52, -0.05). Analyses by study visit suggested that exposure at ∼22 wk (range 20-24 wk) was driving those associations. Bivariate plots from BKMR analysis revealed some nonlinear associations and metabolite interactions that were different between fetal sexes. DISCUSSION: These results suggest that exposure to phthalate mixtures was associated with increased risk of early delivery and highlight the need to study mixtures by fetal sex. We also identified various metabolites displaying nonlinear relationships with measures of birth weight. https://doi.org/10.1289/EHP8990.

The association between urinary glyphosate and aminomethyl phosphonic acid with biomarkers of oxidative stress among pregnant women in the PROTECT birth cohort study.

BACKGROUND: Glyphosate is a widely used herbicide in global agriculture. Glyphosate and its primary environmental degradate, aminomethyl phosphonic acid (AMPA), have been shown to disrupt endocrine function and induce oxidative stress in in vitro and animal studies. To our knowledge, these relationships have not been previously characterized in epidemiological settings. Elevated urinary levels of glyphosate and AMPA may be indicative of health effects caused by previous exposure via multiple mechanisms including oxidative stress. METHODS: Glyphosate and AMPA were measured in 347 urine samples collected between 16 and 20 weeks gestation and 24-28 weeks gestation from pregnant women in the PROTECT birth cohort. Urinary biomarkers of oxidative stress, comprising 8-isoprostane-prostaglandin-F2α (8-iso-PGF2α), its metabolite 2,3-dinor-5,6-dihydro-15-F2 t-isoprostane (8-isoprostane metabolite) and prostaglandin-F2α (PGF2α), were also measured. Linear mixed effect models assessed the association between exposures and oxidative stress adjusting for maternal age, smoking status, alcohol consumption, household income and specific gravity. Potential nonlinear trends were also assessed using tertiles of glyphosate and AMPA exposure levels. RESULTS: No significant differences in exposure or oxidative stress biomarker concentrations were observed between study visits. An interquartile range (IQR) increase in AMPA was associated with 9.5% (95% CI: 0.5-19.3%) higher 8-iso-PGF2α metabolite concentrations. Significant linear trends were also identified when examining tertiles of exposure variables. Compared to the lowest exposure group, the second and third tertiles of AMPA were significantly associated with 12.8% (0.6-26.5%) and 15.2% (1.8-30.3%) higher 8-isoprostane metabolite, respectively. An IQR increase in glyphosate was suggestively associated with 4.7% (-0.9 to 10.7%) higher 8-iso-PGF2α. CONCLUSIONS: Urinary concentrations of the main environmental degradate of glyphosate, AMPA, were associated with higher levels of certain oxidative stress biomarkers. Associations with glyphosate reflected similar trends, although findings were not as strong. Additional research is required to better characterize the association between glyphosate exposure and biomarkers of oxidative stress, as well as potential downstream health consequences.

Mediation by hormone concentrations on the associations between repeated measures of phthalate mixture exposure and timing of delivery.

BACKGROUND: Phthalates are used in the manufacturing of consumer products, resulting in ubiquitous human exposure to phthalate mixtures. Previous work has suggested that phthalates display endocrine-disrupting capabilities, and exposure is associated with early delivery. OBJECTIVE: To assess mediating effects of hormone concentrations on associations between phthalate mixtures and preterm birth (PTB). METHODS: Repeated urinary phthalates and serum hormones were measured among 1011 women in the PROTECT Puerto Rico birth cohort from 2011-2019. We utilized ridge regression to create phthalate environmental risk scores (ERS), which represent weighted summaries of total phthalate exposure. Mediation analyses were conducted on a subset of 705 women. We additionally conducted fetal sex-specific analyses. RESULTS: Free thyroxine (FT4) mediated 9.6% of the association between high molecular weight (HMW) ERS at 18 weeks and reduced gestational age at delivery (95%CI:1.07-29.9). Progesterone at 26 weeks mediated 21.1% and 16.2% of the association between HMW ERS at 18 and 22 weeks, and spontaneous PTB, respectively. Among male fetuses, corticotropin releasing hormone (CRH) at 18 weeks mediated 28.2% of the association between low molecular weight ERS and spontaneous PTB. SIGNIFICANCE: We provide introductory evidence of hormone disruption on the causal pathway between phthalate exposure and early delivery. We also show differences by fetal sex, but larger sample size is necessary to validate our findings. IMPACT STATEMENT: This study provides introductory evidence that an alteration of hormone concentrations occurs on the causal pathway between gestational phthalate mixture exposure and subsequent PTB. In addition to the novel application of repeated biomarker measurements and mixtures methods in causal mediation analyses, we also explored differences between classes of phthalate compounds and between fetal sexes. We show that differential endocrine pathways may be disrupted with exposures to low versus HMW phthalate compounds, and that pregnancies with a male fetus may be more susceptible to endocrine disruption than those with a female fetus.

Personal care products: Demographic characteristics and maternal hormones in pregnant women from Puerto Rico.

Personal care products (PCPs) refer to a wide variety of items commonly characterized as health or beauty products. PCPs contain a number of ingredients, often including a wide range of endocrine disrupting chemicals such as phthalates and parabens. The present study examines the association between self-reported PCP use and prenatal sex-steroids and thyroid hormones levels in women from Puerto Rico. We recruited pregnant women (n = 1070) through the Puerto Rico PROTECT Cohort and collected blood, demographic and pregnancy-related data at recruitment and subsequent visits. PCP use in the 48-h preceding the blood sample was collected through self-reported questionnaires. Nine hormones (corticotropin-releasing hormone [CRH], sex-hormone binding globulin [SHBG], estriol [E3], progesterone, testosterone, thyroid-stimulating hormone [TSH], total triiodothyronine [T3], total thyroxine [T4], and free thyroxine [fT4]) were measured in maternal serum samples at two points during pregnancy. Linear mixed models with random intercepts were used to examine associations between PCP use and serum hormone levels. Use of cosmetics significantly increased with age, household income and education level (p < 0.01). Use of hair products, such as hair dyes and bleach, relaxers, and mousse, was associated with lower levels of all sex steroid hormones compared to non-use: SHBG (%Δ = -7.1, 95%CI: -12.4,-1.8), E3 (%Δ = -23.2, 95%CI: -32.2,-13.0), progesterone (%Δ = -21.5, 95%CI: -29.4,-12.9) and testosterone (%Δ = -21.5, 95%CI: -33.1,-7.8) adjusted for maternal age, education and pre-pregnancy body mass index. Our findings suggest that household income and education level influence PCP use among pregnant women in this study. Use of certain hair products was associated with lower concentrations of sex steroid hormones. Although there are limitations to questionnaire data, characterizing PCP use is inexpensive and may represent exposure from multiple classes of chemicals, including chemicals that may not specifically appear on product labels and/or have not been tested for endocrine disrupting potential, making it a useful complement to chemical biomarker data.

Gestational Hormone Concentrations Are Associated With Timing of Delivery in a Fetal Sex-Dependent Manner.

Background: Early delivery remains a significant public health problem that has long-lasting impacts on mother and child. Understanding biological mechanisms underlying timing of labor, including endocrine disruption, can inform prevention efforts. Methods: Gestational hormones were measured among 976 women in PROTECT, a longitudinal birth cohort in Puerto Rico. We evaluated associations between hormone concentrations at 18 and 26 weeks gestation and gestational age at birth, while assessing effect modification by fetal sex. Exploratory analyses assessed binary outcomes of overall preterm birth (PTB, <37 weeks gestation) and the spontaneous PTB subtype, defined as preterm premature rupture of membranes, spontaneous preterm labor, or both. Multivariable logistic and linear regressions were fit using visit-specific hormone concentrations, and fetal sex-specific effects were estimated using interaction terms. Main outcome models were adjusted for maternal age, education, marital status, alcohol consumption, environmental tobacco smoke exposure, and pre-pregnancy body mass index (BMI). Exploratory models adjusted for maternal age and education. Results: We observed reduced gestational age at birth with higher circulating CRH (ß: -2.73 days, 95% CI: -4.97, -0.42), progesterone (ß: -4.90 days, 95% CI: -7.07, -2.73), and fT4 concentrations (ß: -2.73 days, 95% CI: -4.76, -0.70) at 18 weeks specifically among male fetuses. Greater odds of overall and spontaneous PTB were observed among males with higher CRH, estriol, progesterone, total triiodothyronine (T3), and free thyroxine (fT4) concentrations. Greater odds of PTB among females was observed with higher testosterone concentrations. Conclusions: Various associations between hormones and timing of delivery were modified by fetal sex and timing of hormone measurement. Future studies are needed to understand differential mechanisms involved with timing of labor between fetal sexes.

Prenatal Exposure to Glyphosate and Its Environmental Degradate, Aminomethylphosphonic Acid (AMPA), and Preterm Birth: A Nested Case-Control Study in the PROTECT Cohort (Puerto Rico).

BACKGROUND: Glyphosate (GLY) is the most heavily used herbicide in the world. Despite nearly ubiquitous exposure, few studies have examined prenatal GLY exposure and potentially adverse pregnancy outcomes. Preterm birth (PTB) is a risk factor for neonatal mortality and adverse health effects in childhood. OBJECTIVES: We examined prenatal exposure to GLY and a highly persistent environmental degradate of GLY, aminomethylphosphonic acid (AMPA), and odds of PTB in a nested case-control study within the ongoing Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) pregnancy cohort in northern Puerto Rico. METHODS: GLY and AMPA in urine samples collected at 18±2 (Visit 1) and 26±2 (Visit 3) wk gestation (53 cases/194 randomly selected controls) were measured using gas chromatography tandem mass spectrometry. Multivariable logistic regression was used to estimate associations with PTB (delivery <37wk completed gestation). RESULTS: Detection rates in controls were 77.4% and 77.5% for GLY and 52.8% and 47.7% for AMPA, and geometric means (geometric standard deviations) were 0.44 (2.50) and 0.41 (2.56) µg/L for GLY and 0.25 (3.06) and 0.20 (2.87) µg/L for AMPA, for Visits 1 and 3, respectively. PTB was significantly associated with specific gravity-corrected urinary GLY and AMPA at Visit 3, whereas associations with levels at Visit 1 and the Visits 1-3 average were largely null or inconsistent. Adjusted odds ratios (ORs) for an interquartile range increase in exposure at Visit 3 were 1.35 (95% CI: 0.99, 1.83) and 1.67 (95% CI: 1.26, 2.20) for GLY and AMPA, respectively. ORs for Visit 1 and the visit average were closer to the null. DISCUSSION: Urine GLY and AMPA levels in samples collected near the 26th week of pregnancy were associated with increased odds of PTB in this modestly sized nested case-control study. Given the widespread use of GLY, multiple potential sources of AMPA, and AMPA's persistence in the environment, as well as the potential for long-term adverse health effects in preterm infants, further investigation in other populations is warranted. https://doi.org/10.1289/EHP7295.

Maternal lipidomic signatures in relation to spontaneous preterm birth and large-for-gestational age neonates.

Lipidome-wide metabolites may be useful biomarkers of pregnancy outcomes. We sought to characterize maternal lipidomic signatures associated with preterm birth and neonatal anthropometric parameters. Plasma samples were collected 24-28 weeks gestation, and lipidomic profiling was quantified using high-performance liquid chromatography tandem mass spectrometry. Lipid metabolites were analyzed individually and as whole lipid classes and subgroups based on degree of hydrocarbon chain saturation. Associations were estimated using linear and logistic regression. After false discovery adjustment (q < 0.15), four plasmenyl-phosphatidylethanolamines and three free fatty acids associated with increased risk for spontaneous preterm birth. Five phosphatidylinositols, two phosphatidylglycerols, and one phosphatidic acid were associated with large for gestational age neonates. The saturated plasmenyl-phosphatidylethanolamines held the association with increased risk for spontaneous preterm birth. Both the mono- and poly-unsaturated free fatty acids held the association for increased risk for spontaneous preterm birth. Mono- and poly-unsaturated phosphatidylinositols were associated with large for gestational age neonates. Whole lipid classes (plasmenyl-phophatidylcholines and plasmenyl-phosphatidylethanolamines) were associated with increased risk for large for gestational age at delivery. This study provides evidence that finer omics-scale analysis of the maternal lipidome may be more informative biomarkers of pregnancy outcomes compared to whole class level lipid analysis.

Individual and joint effects of phthalate metabolites on biomarkers of oxidative stress among pregnant women in Puerto Rico.

Exposures to phthalate compounds have been linked to adverse birth outcomes, potentially through oxidative stress mechanisms. We explored associations between mixtures of biomarkers of phthalate and phthalate replacement metabolites and oxidative stress using lipid peroxidation biomarker 8-iso-prostaglandin-F2α (8-iso-PGF2α). As 8-iso-PGF2α can be generated via both chemical (nonenzymatic) and enzymatic lipid peroxidation pathways, we calculated the ratio of 8-iso-PGF2α/prostaglandin F2α in an attempt to distinguish the potential contributions of the two pathways. Urinary biomarker measurements were taken from 775 pregnant women in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) longitudinal birth cohort at up to three time points during gestation (16-20, 20-24, and 24-28 weeks gestation). Adaptive elastic net with pairwise linear interaction terms (adENET-I) was used to determine individual phthalate metabolites and phthalate interactions that were predictive of lipid oxidative stress biomarkers, and to subsequently create environmental risk scores (ERS) to represent weighted sums of phthalate exposure for each individual at each study visit. Repeated ERS were then used in linear mixed effects models to test for associations between biomarkers of phthalate mixtures and biomarkers of oxidative stress. We also used Bayesian kernel machine regression (BKMR) to explore nonlinearity and interactions between phthalate metabolites within the mixture. An increase from the first to fourth quartile of phthalate ERS derived from adENET-I was associated with a 96.7% increase (95% CI: 74.0, 122) in the hypothesized chemical fraction of 8-iso-PGF2α and a 268% increase (95% CI: 139, 465) in the hypothesized enzymatic fraction of 8-iso-PGF2α. BKMR analyses also suggested strong linear associations between the phthalate mixture and biomarkers of lipid oxidative stress. Various phthalates displayed nonlinear relationships with both chemical and enzymatic fractions of 8-iso-PGF2α, and we observed some evidence of interactions between metabolites in the mixture. In conclusion, exposure to phthalate mixtures was strongly associated with linear increases in biomarkers of lipid oxidative stress, and differences observed between hypothesized chemical and enzymatic lipid peroxidation outcomes highlight the need to critically assess pathways of 8-iso-PGF2α generation in relation to environmental exposures.

Maternal Urinary Metal and Metalloid Concentrations in Association with Oxidative Stress Biomarkers.

Metal exposure has been associated with a wide range of adverse birth outcomes and oxidative stress is a leading hypothesis of the mechanism of action of metal toxicity. We assessed the relationship between maternal exposure to essential and non-essential metals and metalloids in pregnancy and oxidative stress markers, and sought to identify windows of vulnerability and effect modification by fetal sex. In our analysis of 215 women from the PROTECT birth cohort study, we measured 14 essential and non-essential metals in urine samples at three time points during pregnancy. The oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite 2,3-dinor-5,6-dihydro-15-15-F2t-IsoP, as well as prostaglandin F2α (PGF2α), were also measured in the same urine samples. Using linear mixed models, we examined the main effects of metals on markers of oxidative stress as well as the visit-specific and fetal sex-specific effects. After adjustment for covariates, we found that a few urinary metal concentrations, most notably cesium (Cs) and copper (Cu), were associated with higher 8-iso-PGF2α with effect estimates ranging from 7.3 to 14.9% for each interquartile range, increase in the metal concentration. The effect estimates were generally in the same direction at the three visits and a few were significant only among women carrying a male fetus. Our data show that higher urinary metal concentrations were associated with elevated biomarkers of oxidative stress. Our results also indicate a potential vulnerability of women carrying a male fetus.

Association of biomarkers of exposure to metals and metalloids with maternal hormones in pregnant women from Puerto Rico.

BACKGROUND: Metal(loid)s have been associated to adverse birth outcomes in experimental and epidemiological studies, but the underlying mechanism(s) are not well understood. Endocrine disruption may be a mechanism by which the metal(loid)s impact birth outcomes. METHODS: Pregnant women were recruited through the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT). Urine, blood, demographic and pregnancy-related data were collected at recruitment and subsequent visits. Sixteen metal(loid)s were analyzed in urine and blood samples, while nine maternal hormones (corticotropin-releasing hormone (CRH), sex-hormone binding globulin (SHBG), estriol (E3), progesterone, testosterone, thyroid-stimulating hormone (TSH), total triiodothyronine (T3), total thyroxine (T4), and free thyroxine (fT4)) were measured in serum samples from 815 singleton pregnancies. Linear mixed models with random intercepts were used to examine associations between metal(loid)s in blood and urine with hormone concentrations. RESULTS: Arsenic blood concentrations were significantly associated with increased levels in CRH (%Δ: 23.0, 95%CI: 8.4-39.6) and decreased levels in testosterone (%Δ: -16.3, 95%CI: -26.2--5.1). Cobalt, manganese, and lead blood concentrations were associated with small increases in SHBG (%Δ range: 3.3-4.2), E3 (%Δ range: 3.9-8.7) and progesterone (%Δ range: 4.1-6.3) levels, respectively. Nickel blood concentration was inversely associated with testosterone levels (%Δ -13.3, 95%CI: -18.7--7.6). Significant interactions were detected for the association between nickel and study visit in relation to CRH (p < 0.02) and testosterone levels (p < 0.01). CONCLUSION: Our analysis suggests that metal(loid)s may act as endocrine disruptors by altering prenatal hormone levels. This disruption may depend on specific windows of exposure during pregnancy. Additionally, some essential metal(loid)s such as managense and cobalt may be contributors to adverse maternal and fetal outcomes. The study of metal(loid)s as endocrine disruptors is in the early stages of epidemiological research and future studies are needed to further investigate these associations.

Polycyclic aromatic hydrocarbon exposure results in altered CRH, reproductive, and thyroid hormone concentrations during human pregnancy.

Polycyclic aromatic hydrocarbons (PAHs) are byproducts of incomplete combustion reactions and are ubiquitous in the environment, leading to widespread human exposure via inhalation and ingestion pathways. PAHs have been implicated as endocrine disrupting compounds in previous animal and in vitro studies, but human studies are currently lacking. Pregnant women and their developing fetuses are particularly susceptible populations to environmental contaminants, in part because alterations in hormone physiology during gestation can have adverse consequences on the health of the pregnancy. We utilized data on 659 pregnant women from the PROTECT longitudinal birth cohort in Puerto Rico to assess associations between repeated measures of 8 urinary hydroxylated PAH (OH-PAH) metabolites and 9 serum hormones during gestation. Urine samples were collected at 3 study visits (median gestational ages of 18, 22, and 26 weeks at each visit, respectively) and serum samples were collected at the first and third study visits. Linear mixed effects models were used to ascertain longitudinal associations between OH-PAHs and hormones, and sensitivity analyses were employed to assess potential nonlinearity and differences in associations on the basis of fetal sex and timing of biomarker measurement. Among the multiple positive associations we observed between OH-PAHs and CRH, estriol, progesterone, T3, and the ratio of T3 to T4, and inverse associations with testosterone, the most notable are a 24.3% increase (95% CI: 13.0, 36.7) in CRH with an interquartile range (IQR) increase in 1-hydroxyphenanthrene and a 17.2% decrease (95% CI: 8.13, 25.4) in testosterone with an IQR increase in 1-hydroxynapthalene. Many associations observed were dependent on fetal sex, and some relationships showed evidence of nonlinearity. These findings demonstrate the importance of studying PAH exposures during pregnancy and highlight the potential complexity of their impacts on the physiology of human pregnancy.

Cohort profile: Center for Research on Early Childhood Exposure and Development in Puerto Rico.

PURPOSE: Puerto Rican children experience high rates of asthma and obesity. Further, infants born in Puerto Rico are more at risk for being born prematurely compared with infants on the mainland USA. Environmental exposures from multiple sources during critical periods of child development, potentially modified by psychosocial factors, may contribute to these adverse health outcomes. To date, most studies investigating the health effects of environmental factors on infant and child health have focused on single or individual exposures. PARTICIPANTS: Infants currently in gestation whose mother is enrolled in Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort, and infants and children already born to mothers who participated in the PROTECT study. FINDINGS TO DATE: Data collection and processing remains ongoing. Demographic data have been collected on 437 mother-child pairs. Birth outcomes are available for 420 infants, neurodevelopmental outcomes have been collected on 319 children. Concentrations of parabens and phenols in maternal spot urine samples have been measured from 386 mothers. Center for Research on Early Childhood Exposure and Development mothers have significantly higher urinary concentrations of dichlorophenols, triclosan and triclocarban, but lower levels of several parabens compared with reference values from a similar population drawn from the National Health and Nutrition Examination Survey. FUTURE PLANS: Data will continue to be collected through recruitment of new births with a target of 600 children. Seven scheduled follow-up visits with existing and new participants are planned. Further, our research team continues to work with healthcare providers, paediatricians and early intervention providers to support parent's ability to access early intervention services for participants.

Maternal blood metal and metalloid concentrations in association with birth outcomes in Northern Puerto Rico.

BACKGROUND: In previous studies, exposures to heavy metals such as Pb and Cd have been associated with adverse birth outcomes; however, knowledge on effects at low levels of exposure and of other elements remain limited. METHOD: We examined individual and mixture effects of metals and metalloids on birth outcomes among 812 pregnant women in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort. We measured 16 essential and non-essential metal(loid)s in maternal blood collected at 16-20 and 24-28 weeks gestation. We used linear and logistic regression to independently examine associations between geometric mean (GM) concentrations of each metal across visits and gestational age, birthweight z-scores, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). We evaluated effect modification with infant sex*metal interaction terms. To identify critical windows of susceptibility, birth outcomes were regressed on visit-specific metal concentrations. Furthermore, average metal concentrations were divided into tertiles to examine the potential for non-linear relationships. We used elastic net (ENET) regularization to construct Environmental Risk Score (ERS) as a metal risk score and Bayesian Kernel Machine Regression (BKMR) to identify individual metals most critical to each outcome, accounting for correlated exposures. RESULTS: In adjusted models, an interquartile range (IQR) increase in GM lead (Pb) was associated with 1.63 higher odds of preterm birth (95%CI = 1.17, 2.28) and 2 days shorter gestational age (95% CI = -3.1, -0.5). Manganese (Mn) and zinc (Zn) were also associated with higher odds of preterm birth and shorter gestational age; the associations were strongest among the highest tertile for Mn and among females for Zn. Mercury (Hg) was associated with higher risk of preterm birth at the later window of pregnancy. Ni measured later in pregnancy was associated with lower odds of SGA. ENET and BKMR models selected similar metals as "important" predictors of birth outcomes. The association between ERS and preterm birth was assessed and the third tertile of ERS was significantly associated with an elevated odds ratio of 2.13 (95% CI = 1.12, 5.49) for preterm birth compared to the first tertile. CONCLUSION: As the PROTECT cohort has lower Pb concentrations (GM = 0.33 µg/dL) compared to the mainland US, our findings suggest that low-level prenatal lead exposure, as well as elevated Mn and Zn exposure, may adversely affect birth outcomes. Improved understanding on environmental factors contributing to preterm birth, together with sustainable technologies to remove contamination, will have a direct impact in Puerto Rico and elsewhere.

Predictors of urinary and blood Metal(loid) concentrations among pregnant women in Northern Puerto Rico.

Given the potential adverse health effects related to toxic trace metal exposure and insufficient or excessive levels of essential trace metals in pregnant women and their fetuses, the present study characterizes biomarkers of metal and metalloid exposure at repeated time points during pregnancy among women in Puerto Rico. We recruited 1040 pregnant women from prenatal clinics and collected urine, blood, and questionnaire data on demographics, product use, food consumption, and water usage at up to three visits. All samples were analyzed for 16 metal(loid)s: arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), titanium (Ti), uranium (U), vanadium (V), and zinc (Zn). Urine samples were additionally analyzed for molybdenum (Mo), platinum (Pt), antimony (Sb), tin (Sn), and tungsten (W). Mean concentrations of most metal(loid)s were higher among participants compared to the general US female population. We found weak to moderate correlations for inter-matrix comparisons, and moderate to strong correlations between several metal(loid)s measured within each biological matrix. Blood concentrations of Cu, Zn, Mn, Hg, and Pb were shown to reflect reliable biomarkers of exposure. For other metals, repeated samples are recommended for exposure assessment in epidemiology studies. Predictors of metal(loid) biomarkers included fish and rice consumption (urinary As), fish and canned food (blood Hg), drinking public water (blood Pb), smoking (blood Cd), and iron/folic acid supplement use (urinary Cs, Mo, and Sb). Characterization of metal(loid) biomarker variation over time and between matrices, and identification of important exposure sources, may inform future epidemiology studies and exposure reduction strategies.

Repeated measures of urinary oxidative stress biomarkers and preterm birth in Puerto Rico.

BACKGROUND: Preterm birth (PTB; gestational age <37 weeks), the leading cause of infant morbidity and mortality worldwide, is of particular concern in Puerto Rico. Rates of PTB in Puerto Rico peaked at 20% in 2006, which are historically some of the highest in the world. Oxidative stress and inflammation have been implicated as contributors to adverse birth outcomes, including PTB, and these associations have not been explored in Puerto Rico. Our objective was to examine associations between urinary oxidative stress biomarkers and PTB in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) pregnancy cohort (N = 469). METHODS: 8-iso-prostaglandin F2α (8-iso-PGF2α), its primary metabolite, and prostaglandin F2α (PGF2α) were included as biomarkers of oxidative stress or inflammation. Biomarkers were measured in urine samples collected at up to 3 timepoints across pregnancy (mean 18, 24, 28 weeks gestation). We quantified the proportion of 8-iso-PGF2α originating from oxidative stress and inflammation pathways with a formula based on the ratio of 8-iso-PGF2α to PGF2α. Logistic regression models were used to calculate adjusted odds ratios (OR) for associations between average biomarker concentrations from each woman (visits 1-3) and PTB. Associations between biomarker concentrations at each study visit and PTB were analyzed in separate models. RESULTS: Averaged levels of 8-iso-PGF2α, its primary metabolite, and PGF2α were associated with increased odds of PTB (OR = 1.64, 95% confidence interval [CI] = 1.07-2.54; OR = 1.79, 95% CI = 1.14-2.84; OR = 1.98, 95% CI = 1.32-3.02, respectively). Odds ratios for PTB were greater in magnitude in association with oxidative stress biomarkers measured later in pregnancy. The fraction of 8-iso-PGF2α derived from inflammation was associated with PTB (OR = 1.73, 95% CI = 1.09, 2.93), while the fraction of 8-iso-PGF2α derived from oxidative stress was not associated with PTB (OR = 1.17, 95% CI = 0.90, 1.54). CONCLUSIONS: Our results suggest that oxidative stress and inflammation, as measured by these biomarkers, may be important contributors to PTB. Further research is needed to improve our understanding of the role these biomarkers may play in the causal pathway between environmental factors and PTB.

An exploratory analysis of urinary organophosphate ester metabolites and oxidative stress among pregnant women in Puerto Rico.

BACKGROUND: Organophosphate esters (OPEs) are used as flame retardants and plasticizers. Oxidative stress, the imbalance of reactive oxygen species and antioxidants, measured prenatally has been associated with adverse birth outcomes including preeclampsia and preterm birth. We are the first study to investigate the relationship between OPEs and oxidative stress among pregnant women. METHODS: Pregnant women 18-40 yrs. were recruited in Northern Puerto Rico (n = 47) between 2011 and 2015. OPE concentrations of: bis(2-chloroethyl) phosphate (BCEtP), bis(1-chloro-2-propyl) phosphate (BCPP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), dibutyl phosphate (DNBP), and diphenyl phosphate (DPHP) and biomarkers for oxidative stress, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostane were measured in urine up to three times during pregnancy. Associations between oxidative stress biomarkers and OPEs were assessed using linear mixed models adjusted for specific gravity, age, BMI, and income. RESULTS: Metabolites BCEtP, BDCPP, and DPHP were frequently detected (>97%). OPE metabolite concentrations remained stable over time (Intraclass correlation coefficients (ICCs): 0.51-0.60). Metabolites BCEtP, BCPP, and DPHP were associated with an increase in 8-isoprostane and OHdG. An interquartile range (IQR) increase in BDCPP was associated with a 21% increase in 8-isoprostane (p < 0.01), while and IQR increase in DPHP and BCPP was associated with a 12% increase (p = 0.04, p = 0.08, respectively). IQR increases in BDCPP and DPHP were also associated with an 18 and 19% increase in OHdG, respectively (p < 0.01). CONCLUSION: OPE metabolites were frequently detected and our results suggest that exposure to OPEs is associated with higher levels of oxidative stress. Further investigation into these relationships and birth outcomes is warranted.

Interactions between chemicals and non-chemical stressors: The modifying effect of life events on the association between triclocarban, phenols and parabens with gestational length in a Puerto Rican cohort.

BACKGROUND: Phenols and parabens are common additives to consumer products. There is evidence of adverse birth outcomes in association with prenatal exposure to these chemicals, in addition to psychosocial factors. We previously reported an increase in gestational length with bisphenol-A, methylparaben and propylparaben, and a decrease in gestational length with triclocarban. OBJECTIVES: We examined the modifying effect of psychosocial stress on the association between chemicals and gestational length in up to 752 women among a pregnancy cohort study. METHODS: Urinary biomarkers were measured at up to three time points in pregnancy. Multiple linear regression models were conducted to investigate the association between gestational length and the interaction between average exposure biomarkers and LES. Multiple linear regression models regressing the exposure biomarkers in relation to gestational length were also stratified by LES, Negative LES, and Positive LES, based on the subjective ratings of events. Results were transformed into the change in gestational length for an inter-quartile-range difference in the exposure. RESULTS: Of the four psychosocial stress measures, only the life events score (LES) was a significant modifier. Associations between triclocarban, bisphenol-S, methyl- and propylparaben in relation to gestational length were stronger among women with negative Total LES scores. Among women with negative Total LES scores, bisphenol-S and triclocarban were associated with a 3-5 day decrease in gestational length [(-3.15; 95% CI: -6.06, -0.24); (-4.68; 95% CI: -8.47, -0.89)], whereas methylparaben and propylparaben were associated with a 2-3 day increase in gestational length [(2.21; 95% CI: 0.02, 4.40); (2.92; 95% CI: 0.58, 5.26)]. Significant interactions were driven by negative life events, but the association with triclocarban was driven by few positive life events. CONCLUSIONS: Associations between exposure biomarkers and gestational length were stronger in the presence of negative life events. This provides evidence that stress makes the body more vulnerable to chemical exposure.

Determinants and characterization of exposure to phthalates, DEHTP and DINCH among pregnant women in the PROTECT birth cohort in Puerto Rico.

BACKGROUND: As a result of evidence suggesting phthalate toxicity, their use has decreased in recent years. However, new phthalates and non-phthalate replacements have emerged in their place, with unknown potential impacts on health. METHODS: We measured 15 phthalate, two di(2-ethylhexyl)terephthalate (DEHTP), and two di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH) urinary metabolites, collected up to three times during pregnancy from 994 women in Northern Puerto Rico (2011-2017). We used tests of linear trend to assess changes in concentrations over time and linear mixed models to identify predictors of exposure (sociodemographic characteristics, drinking water sources, diet, product use). RESULTS: Several phthalate metabolites decreased over the study period indicating decreased exposure, while the geometric mean of DEHTP metabolites (molecular sum) increased threefold between 2014 and 2017. Intraclass correlations revealed low to moderate reproducibility of these biomarkers across pregnancy. Several metabolites were associated with maternal age, income, education, pre-pregnancy BMI, drinking public water, use of cleaning and personal care products, and ice cream consumption. DINCH metabolite concentrations remained low throughout the study period. CONCLUSION: Although exposure to some phthalates may be decreasing, exposure to replacements, such as DEHTP, is increasing. Additional studies are needed to further characterize sources of phthalate replacement chemicals and potential exposure-related health effects among vulnerable populations.

Investigating the impact of Hurricane Maria on an ongoing birth cohort in Puerto Rico.

Prior to Hurricane Maria, Puerto Rico already had 200+ hazardous waste sites, significant contamination of water resources, and among the highest rates of preterm birth in the US. To address these issues, the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) Center was formed in 2010 to investigate prenatal environmental exposures, particularly phthalates, and adverse birth outcomes. Recent work from the PROTECT study confirms that in utero exposure to certain phthalates is associated with shorter gestation and increased risk of preterm birth. However, previous research also suggests that pregnant women who experience a natural disaster such as Hurricane Maria are at higher risk of adverse birth outcomes, but it is unknown whether this is due to stress, hazardous exposures, or a combination of factors. Thus, the aim of this analysis was to characterize hurricane-related changes in phthalate exposures and experiences within the PROTECT cohort. Among 176 participants who were pregnant during or within 5 months after Maria, 122 completed a questionnaire on hurricane-related experiences. Questionnaire results and biomarkers of exposure suggest that participants did not have regular access to fresh foods and water during hurricane recovery, and almost half reported structural damage to their home. In addition, biomarker concentrations of phthalates commonly used in food packaging were higher among participants post-hurricane, while phthalates commonly used in personal care products were lower compared to pre-hurricane levels. Hurricane-related increases in phthalate exposure, as well as widespread structural damage, food and water shortages, and long-term absence of electricity and cell phone service, likely increased the risk of adverse birth outcomes among this already vulnerable population.