Phthalate levels and low birth weight: a nested case-control study of Chinese newborns

Plastics derived endocrine-disrupting compounds and their effects on early development

Despite the fact that the estrogenic effects of bisphenols were first described 80 years ago, recent data about its potential negative impact on birth outcome parameters raises a strong rationale to investigate further. The adverse health effects of plastics recommend to measure the impacts of endocrine-disrupting compounds (EDCs) such as bisphenols (BPA, BPS, BPF), bis(2-ethylhexyl) phthalate, and dibutyl phthalate (DBP) in human health. Exposure to these compounds in utero may program the diseases of the testis, prostate, kidney and abnormalities in the immune system, and cause tumors, uterine hemorrhage during pregnancy and polycystic ovary. These compounds also control the processes of epigenetic transgenerational inheritance of adult-onset diseases by modulating DNA methylation and epimutations in reproductive cells. The early developmental stage is the most susceptible window for developmental and genomic programming. The critical stages of the events for a normal human birth lie between the many transitions occurring between spermatogenesis, egg fertilization and the fully formed fetus. As the cells begin to grow and differentiate, there are critical balances of hormones, and protein synthesis. Data are emerging on how these plastic-derived compounds affect embryogenesis, placentation and feto-placental development since pregnant women and unborn fetuses are often exposed to these factors during preconception and throughout gestation. Impaired early development that ultimately influences fetal outcomes is at the center of many developmental disorders and contributes an independent risk factor for adult chronic diseases. This review will summarize the current status on the impact of exposure to plastic derived EDCs on the growth, gene expression, epigenetic and angiogenic activities of the early fetal development process and their possible effects on birth outcomes.

Human amniotic fluid-based exposure levels of phthalates and bisphenol A mixture reduce INSL3/RXFP2 signaling

BACKGROUND

The presence of chemical pollutants in the environment can affect human health. Epidemiological and in vivo experimental studies reveal reprotoxic effects (undescended testis) of phthalates (diethylhexyl phthalate (DEHP), dibutyl phthalate (DBP)) and bisphenol A (BPA), resulting in particular of a decrease in INSL3 (Insulin-Like 3 peptide) production. This hormone is essential for normal testis development and acts on a G protein-coupled receptor: RXFP2.

OBJECTIVES

The aim of this study was to evaluate the individual and combined impacts of DEHP, DBP, and BPA on human RXFP2 (hRXFP2) activity.

METHODS

We used HEK293 cells transiently transfected with hRXFP2 and receptor activity was analyzed by measuring intracellular cAMP production. The mixture was established at concentrations reported in human amniotic fluid, for the three compounds.

RESULTS

Individually, DEHP, DBP and BPA increased the response to INSL3 by 19.3 to 27.5%. This potentiating effect was specific for RXFP2, because it was absent in the cells which did not express this receptor. On the other hand, and interestingly, the mixture of the three compounds reduced significantly the response to INSL3 by 12%, and the observed effects were opposite to those predicted, suggesting an antagonist effect.

DISCUSSION-CONCLUSION

Taken together, our results demonstrate for the first time that a mixture of phthalates and BPA present in human amniotic fluid disturbs the human RXFP2 function. Moreover, we demonstrate that mixture can produce potential antagonistic effects that are not displayed by the compounds, individually.

Phthalate metabolites concentrations in amniotic fluid and maternal urine: Cumulative exposure and risk assessment

Phthalates are used in industry as plasticizers or additives in everyday products and they have been considered as endocrine disrupting chemicals. Maternal exposure during pregnancy has been associated with neonatal exposure, preterm birth and impacts in the reproductive and respiratory systems. The aim of this study is to determine six phthalate metabolites (mono isobutyl phthalate, miBP, mono n-butyl phthalate, mnBP, mono benzyl phthalate, mBzP, mono ethylhexyl phthalate, mEHP, mono 2-ethyl-5-hydroxyhexyl phthalate, mEHHP, mono 2-ethyl-5-oxohexyl-phthalate, mEOHP) in amniotic fluid and urine from 100 pregnant women. Participants answered questionnaires for the use of plastics and cosmetics, dietary habits, health effects, pregnancy problems, health and infant development. Positive amniotic fluid samples ranged from 1% to 21% and urine from 27% to 54%. The median levels for amniotic fluid were 2.3 μg/L - 10.7 μg/L and for urine 4.9 μg/L - 46.7 μg/L. The major results include significant correlations between urinary phthalates indicating their common sources of exposure, the frequent use of deodorant was significantly associated with higher urinary miBP (p = 0.050) and mnBP (p = 0.028) and a weak inverse association was found for the use of make-up products with mBzP (p = 0.053). The frequent use of plastic food containers was significantly associated with urinary mEHP (p = 0.026), and a positive trend was noticed for mEHP in amniotic fluid (p = 0.093). An association although weak was found between urinary mEHP and lower birth length (rs = 0.396, p = 0.062). No other associations were found for infant health problems or development. The daily intake of the total phthalates was calculated 5.4 μg/kg body weight/day which corresponds to hazard index 0.10 and exposure follows the declining trend that has been observed the last decades.

Biomonitoring of bisphenols A and S and phthalate metabolites in hair from pregnant women in Crete

Phthalates, bisphenols A and S (BPA, BPS) are used as plasticizers and many of them are documented or suspected of being endocrine disruptors. Several studies indicate that exposure during pregnancy may affect the newborn's health and development. The aim of this cross-sectional study is the biomonitoring of seven phthalate metabolites, BPA and BPS in hair from 100 pregnant women in Crete. The most frequently detected compounds were monoethylhexyl phthalate (mEHP) (68%), mono isobutyl phthalate (miBP) (40%), BPA (37%), BPS (34%) and mono-n-butyl phthalate (mnBP) (28%). Phthalate metabolites were detected at medians from 19.5 to 44.4 pg/mg, BPA at 69.9 pg/mg and BPS at 3.5 pg/mg. Significant positive correlations between phthalate metabolites were found which indicated their common sources of exposure. The frequent use of plastics for food storage was strongly associated with mEHP (p = .013) and a weaker association was found for miBP (p = .063). The frequent use of cosmetics during or before pregnancy was associated with levels of phthalate metabolites in hair. More specifically, the use of hair spray before pregnancy was significantly correlated with monobenzyl phthalate (mBzP) (p = .041) and a trend was found for miBP (p = .066). The use of makeup products during pregnancy was strongly associated with miBP (p = .015) and the use of deodorant during pregnancy was inversely associated with mEHP (p = .021). Strong associations came up between mEHP and lower birth weight (Spearman correlation coefficient, r = -0.302, p = .021) and exposure to BPS was associated with increased body mass index of the participants (p = .036). Although data in literature on biomonitoring of the compounds in hair are limited, the findings of this study are promising and in agreement with existing data in hair or urine.

Associations of urinary di-(2-ethylhexyl) phthalate metabolites with the residential characteristics of pregnant women

Epidemiological evidence on the associations between urinary di-(2-ethylhexyl) phthalate (DEHP) metabolites and residential characteristics is limited. Therefore, we investigated the associations of urinary DEHP metabolites with the residential characteristics of pregnant women. We collected completed questionnaires and maternal spot urine samples from 616 random pregnant women in Shengjing Hospital of China Medical University in Shenyang. Urinary DEHP metabolites concentrations, including mono-(2-ethylhexyl) phthalate (MEHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), were measured and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). Multivariable linear regression models were performed to obtain regression estimates (β) and 95% confidence intervals (CIs) after adjustment for sociodemographic characteristics. In all participants, the geometric mean of MEHP and MEHHP concentrations were 4.25 ± 4.34 and 5.72 ± 2.65 μg/L, respectively. In multivariable analyses after adjusting for sociodemographic characteristics, distance from residence to motor vehicle traffic (≥150 m versus <20 m) was negatively associated with MEHP (β = -0.241, 95% CI: -0.448, -0.033) and MEHHP (β = -0.279, 95% CI: -0.418, -0.140) concentrations. Compared with the one that had not recently been renovated, a renovated home was associated with higher MEHP (β = 0.194, 95% CI: 0.064, 0.324) and MEHHP (β = 0.111, 95% CI: 0.024, 0.197) concentrations. Air freshener use was associated with higher MEHP (β = 0.322, 95% CI: 0.007, 0.636) concentrations. Moldy walls were positively associated with MEHP (β = 0.299, 95% CI: 0.115, 0.482) and MEHHP (β = 0.172, 95% CI: 0.050, 0.294) concentrations. In contrast, humidifier use was associated with a lower MEHP concentration (β = -0.167, 95% CI: -0.302, -0.032). Residential characteristics were probably associated with the DEHP exposure of pregnant women in Shenyang. Living near the motor vehicle traffic, residential renovation, air freshener use, and moldy walls are likely risk factors for increased DEHP exposure, whereas using household humidifier could be considered a protective measure to reduce DEHP exposure.

Oestrogenic Endocrine Disruptors in the Placenta and the Fetus

Endocrine disrupting chemicals (EDCs) are exogenous substances that interfere with the stability and regulation of the endocrine system of the body or its offspring. These substances are generally stable in chemical properties, not easy to be biodegraded, and can be enriched in organisms. In the past half century, EDCs have gradually entered the food chain, and these substances have been frequently found in maternal blood. Perinatal maternal hormone levels are unstable and vulnerable to EDCs. Some EDCs can affect embryonic development through the blood-fetal barrier and cause damage to the neuroendocrine system, liver function, and genital development. Some also effect cross-generational inheritance through epigenetic mechanisms. This article mainly elaborates the mechanism and detection methods of estrogenic endocrine disruptors, such as bisphenol A (BPA), organochlorine pesticides (OCPs), diethylstilbestrol (DES) and phthalates (PAEs), and their effects on placenta and fetal health in order to raise concerns about the proper use of products containing EDCs during pregnancy and provide a reference for human health.

Exposure to DEHP or its metabolite MEHP promotes progesterone secretion and inhibits proliferation in mouse placenta or JEG-3 cells

Di (2-ethyl-hexyl)phthalate (DEHP) is an environmental endocrine disruptor and commonly used as plasticizer. Maternal DEHP exposure during pregnancy reduces placental size and destroys placental structure. However, the underlying mechanisms were unclear. In this study, we supposed that DEHP disturbs endocrine function of placenta to inhibit the proliferation of placental cell. Using radioimmunoassay and ELISA, we found that DEHP and its active metabolite mono (2-ethyl-hexyl) phthalate (MEHP) promoted progesterone secretion in pregnant mouse and in JEG-3 cells, respectively. Therefore, placental endocrine function was altered by DEHP. The mRNA and protein level of progesterone synthetase 3β-HSD1 was elevated by DEHP, which is conducive to the synthesis of progesterone. The level of progesterone receptor was down-regulated by DEHP and MEHP in mouse placenta and in JEG-3 cells, respectively. PR deficiency further promoted the level of 3β-HSD1, which leads to a higher progesterone level. In turn, higher concentration of progesterone further inhibited the expression of PGR (PR gene). Therefore, higher progesterone down-regulated the level of its receptor PR. Meanwhile, decreased PR induced more progesterone secretion. There is a feedback loop between progesterone and PR. PR deficiency down-regulated the protein level of Cyclin D1 which plays an important role in cell proliferation. Accordingly, DEHP and its active metabolite MEHP can restrain proliferation of placental cell and disturb the progesterone secretion via decreasing the level of PR.

Phthalate-Induced Fetal Leydig Cell Dysfunction Mediates Male Reproductive Tract Anomalies

Male fetal Leydig cells in the testis secrete androgen and insulin-like 3, determining the sexual differentiation. The abnormal development of fetal Leydig cells could lead to the reduction of androgen and insulin-like 3, thus causing the male reproductive tract anomalies in male neonates, including cryptorchidism and hypospadias. Environmental pollutants, such as phthalic acid esters (phthalates), can perturb the development and differentiated function of Leydig cells, thereby contributing to the reproductive toxicity in the male. Here, we review the epidemiological studies in humans and experimental investigations in rodents of various phthalates. Most of phthalates disturb the expression of various genes encoded for steroidogenesis-related proteins and insulin-like 3 in fetal Leydig cells and the dose-additive effects are exerted after exposure in a mixture.

Prenatal exposure to phthalates and neurocognitive development in children at two years of age

BACKGROUND

Phthalates are a family of endocrine disruptors with short elimination half-lives in the human body. To date, few epidemiological studies have examined repeated measures of maternal urinary phthalates and the combined effects of prenatal exposure to multiple phthalates on children's neurocognitive development.

OBJECTIVES

We aimed to investigate the association between children's neurocognitive development at 2 years of age and prenatal phthalate exposure, as assessed by repeated measurements during pregnancy, and to further examine the effects of co-exposure to multiple phthalates using cumulative risk assessment.

METHOD

Within a prenatal cohort in Wuhan, China, we measured five high-molecular-weight (HMW) phthalates and three low-molecular-weight (LMW) phthalate metabolites' concentrations in three urine samples collected in the 1st, 2nd, and 3rd trimester of pregnancy from each mother. We assessed neurocognitive development by Bayley Scales of Infant and Toddler Development (BSID) at 2 years of age (n = 476) to obtain the children's mental development index (MDI) and psychomotor development index (PDI).

RESULTS

Higher exposure levels to LMW phthalates compared to HMW phthalates were observed in our population. Ln-transformed averaged concentration of mono-n-butyl phthalate (MnBP), a metabolite of the LMW phthalate di-n-butyl phthalate (DnBP) during pregnancy, was associated with decreased PDI scores in all children (β = -1.90, 95% CI: -3.43, -0.37). Similarly, the averaged sum concentration of ∑dibutyl phthalate (∑DBP) was associated with decreased PDI scores in all children (β = -1.89, 95% CI: -3.63, -0.15). A negative trend of association between exposure to HMW phthalates and PDI scores was observed in girls, while a positive association was found in boys. In cumulative risk assessment analyses, we consistently observed that the hazard quotient of DnBP (the parent compound of MnBP) was inversely associated with PDI scores in all children, whereas the hazard quotient of di-2-ethylhexyl phthalate (DEHP), an HMW phthalate, was positively associated with PDI scores in boys only.

CONCLUSIONS

This study is the first to use repeated measurement of maternal urinary phthalates in all three trimesters to assess prenatal exposure in relation to children's neurodevelopment. Our study suggested a negative association between prenatal exposure to MnBP and children's psychomotor development, and potentially sex-specific associations between HMW phthalates and neurocognitive development among boys and girls. These findings warrant further confirmation.

Biological interactions between nanomaterials and placental development and function following oral exposure

We summarize the literature involving the deposition of nanomaterials within the placenta following oral exposure and the biological interactions between nanomaterials and placental development and function. The review focuses on the oral exposure of metal and metal oxide engineered nanomaterials (ENMs), carbon-based ENMs, and nanoplastics in animal models, with a minor discussion of intravenous injections. Although the literature suggests that the placenta is an efficient barrier in preventing nanomaterials from reaching the fetus, nanomaterials that accumulate in the placenta may interfere with its development and function. Furthermore, some studies have demonstrated a decrease in placental weight and association with adverse fetal health outcomes following oral exposure to nanomaterials. Since nanomaterials are increasingly used in food, food packaging, and have been discovered in drinking water, the risk for adverse impacts on placental development and functions, with secondary effects on embryo-fetal development, following unintentional maternal ingestion of nanomaterials requires further investigation.

Effects of di(2-etilhexil) phthalate on human umbilical artery

Di(2-etilhexil) phthalate (DEHP) is a compound used in plastic materials, which has endocrine disrupting properties. The human DEHP exposure depend on the use of plastics in toys, medical devices and food and beverage containers. The DEHP effects were studied in some physiological systems; nevertheless, the actions in human arteries were never described. We analysed the DEHP effect on endothelium denuded human umbilical artery (HUA), an important artery to ensure gases and nutrients exchange with fetus. We assessed DEHP short-term effects on contractility, occurring few minutes after DEHP is in contact with HUA in the organ bath receptacles. The long-term effects on HUA, observed after 24 h in presence of DEHP, were assessed in the organ bath system, and also through the analysis of receptors expression (5-HT_2A and H₁) and of cellular viability, by using HUA smooth muscle cells. DEHP (1 nM-100 μM) induced a short-term relaxing effect on HUA contracted by 5-HT, histamine or KCl. DEHP long-term exposure of arteries (1 nM, 10 μM and 100 μM) reduced its own relaxant effect on HUA contracted by 5-HT and histamine and, precisely, 24 h exposure to DEHP 1 nM reverted the relaxant effect on 5-HT contractility. Long-term exposure at more than 10 nM of DEHP decreased 5HT_2A receptors expression. In conclusion, DEHP short-term exposition elicit vasodilation of HUA contracted by different agents. DEHP long-term exposition reduced the expression of 5HT_2A receptors. The DEHP long-term exposition decrease the short-term relaxant effect and, at low concentrations can increase the contractile effect of 5-HT.

Human placental 3β-hydroxysteroid dehydrogenase/steroid Δ5,4-isomerase 1: Identity, regulation and environmental inhibitors

Human placental 3β-hydroxysteroid dehydrogenase/steroid Δ5, 4-isomerase 1 (HSD3B1), a high-affinity type I enzyme, uses pregnenolone to make progesterone, which is critical for maintenance of pregnancy. HSD3B1 is located in the mitochondrion and the smooth endoplasmic reticulum of placental cells and is encoded by HSD3B1 gene. HSD3B1 contains GATA and TEF-5 regulatory elements. Many endocrine disruptors, including phthalates, methoxychlor and its metabolite, organotins, and gossypol directly inhibit placental HSD3B1 thus blocking progesterone production. In this review, we discuss the placental HSD3B1, its gene regulation, biochemistry, subcellular location, and inhibitors from the environment.

Phthalate exposure from drugs during pregnancy and possible risk of preterm birth and small for gestational age

BACKGROUND

Phthalates are chemical compounds present in a wide range of consumer products and are thought to be endocrine disruptors. Though not commonly known, phthalates are present in some medication with previous studies finding up to 50-fold higher urinary metabolite concentrations among exposed compared to the general population. Previous studies on environmental phthalate exposure and pregnancy outcomes have been contradictory and inconclusive and all previous studies have assessed phthalate exposure using biomarkers despite a known rapid metabolism of phthalates.

OBJECTIVE

To determine whether phthalate exposure from pharmaceutical drugs have effects on preterm birth (PTB) and small for gestational age (SGA).

STUDY DESIGN

We conducted a nested case-control study among women in Denmark with a recorded singleton birth and included women who conceived between January 1st, 2004 and December 31st, 2015. To mitigate drug effect and confounding by underlying disease we included pregnancies exposed to selected study drugs, and compared pregnancies exposed to phthalate containing drugs to pregnancies exposed to phthalate free generic drugs. Using Danish health registries, we identified 30,899 singleton pregnancies exposed to study drugs available in both phthalate-containing and phthalate free versions. Using conditional logistic regression, we estimated associations between phthalate exposure and the risk of PTB and SGA. Birth weight according to gestational age was defined by INTERGROWTH-21st (SGA-I) and by Marsal's equation (SGA-M) for expected birthweight.

RESULTS

We included 1965 PTBs, 1315 SGA-Is, and 891 SGA-M cases, matched to 19,537, 12,008, and 7573 controls, respectively. Orthophthalate exposure during the third trimester was positively associated with PTB with a crude OR of 1.36 (95% CI: 1.06-1.76). The association was mainly due to diethyl phthalate. Exposure to phthalate polymers in third trimester was associated with a risk of PTB with crude ORs of 2.08 (CI: 1.16-3.71. No associations were found between orthophthalate or phthalate polymer exposure and SGA.

CONCLUSION

Exposure to some phthalate-containing pharmaceutical drugs during third trimester is associated with preterm birth.

Physicochemical and sensory properties of milk supplemented with lactase microcapsules coated with enteric coating materials

In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (β-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.

Fetal growth in environmental epidemiology: mechanisms, limitations, and a review of associations with biomarkers of non-persistent chemical exposures during pregnancy

BACKGROUND

Non-persistent chemicals, such as phthalates, environmental phenols, organophosphate pesticides, and others, are challenging to study because of their ubiquity in the environment, diverse exposure routes, and high temporal variability of biomarkers. Nonetheless, there is interest in understanding how gestational exposure to these chemicals may affect fetal growth, as perturbations to normal fetal growth are related to a plethora of adverse health outcomes in childhood and adulthood.

METHODS

The purpose of this review is to describe the state of the science on this topic. We searched PubMed for studies that included both 1) biomarkers of non-persistent chemicals collected during pregnancy and 2) fetal growth outcomes measured at birth (e.g., birth weight) or by ultrasound in utero (e.g., estimated fetal weight).

RESULTS

The bulk of the literature we found uses biomarkers measured at a single time point in pregnancy and birth weight as the primary measure of fetal growth. There is a small, but growing, body of research that uses ultrasound measures to assess fetal growth during pregnancy. In addition to summarizing the findings of the publications we identified, we describe inconsistencies in methodology, areas for improvement, and gaps in existing knowledge that can be targeted for improvement in future work. This literature is characterized by variability in methodology, likely contributing to the inconsistency of results reported. We further discuss maternal, placental, and fetal pathways by which these classes of chemicals may affect fetal growth.

CONCLUSIONS

To improve understanding of how everyday chemical exposures affect fetal growth, and ultimately lifelong health outcomes, mechanisms of toxicant action should be considered alongside improved study designs for future hypothesis-driven research.

Perinatal Exposure to Environmental Endocrine Disruptors in the Emergence of Neurodevelopmental Psychiatric Diseases: A Systematic Review

Background: Exposure to endocrine disruptors is on the rise, with new compounds regularly incriminated. In animals and humans, this exposure during critical developmental windows has been associated with various developmental abnormalities, including the emergence of psychiatric disorders. We aimed to review the association between perinatal endocrine disruptor exposure and neurodevelopmental disorders in humans, focusing on cognitive and psychiatric disorders. Methods: We performed a systematic review with key words referring to the fields of neurodevelopment and endocrine disruptors. We reviewed 896 titles, choosing studies on the basis of titles and abstracts. We searched through the methodology sections to find perinatal exposure and neurodevelopmental disorders, following the categories indicated in the Diagnostic and Statistic Manual of Mental Disorders (5^th edition). References in some studies brought us to a total of 47 studies included here. Results: Convergent studies report an association between exposure to endocrine disruptors and autism spectrum disorder, attention-deficit hyperactivity disorder, global developmental delay, intellectual disability, communication disorders and unspecified neurodevelopmental disorders. Conclusion: Sufficient data exist to report that exposure to some endocrine disruptors is a risk factor for the emergence of neurodevelopmental disorders. Studying endocrine disruptor exposure in humans is still associated with some limits that are difficult to overcome.

Food components and environmental chemicals of inhibiting human placental aromatase

Human placental CYP19A1 catalyzes the estrogen synthesis from androgens. The enzyme is encoded by CYP19A1 gene located in chromosome 15q21. This enzyme is a monooxygenase in the smooth endoplasmic reticulum. The various promoters of the CYP19A1 gene determine its expression in different tissues and the distal promoter I.1 controls its expression in the placenta and retinoids can regulate the expression. Many food components and environmental chemicals inhibit CYP19A1 activity via different modes of action. These chemicals include gossypol, flavones, flavanones, chalconoids, resveratrol, and tobacco alkaloids derived from foods as well as phthalates, insecticides, fungicides, and biocides in the contaminated foods. The inhibition of placental CYP19A1 could impair pregnancy.

Household renovation before and during pregnancy in relation to preterm birth and low birthweight in China

From October 2010 to April 2012, we conducted a cross-sectional study of associations between household environments and childhood health among preschool children in eight Chinese cities. Here, we analyze associations of early household renovation with preterm birth (PTB), low birthweight (LBW), term low birthweight (Term-LBW), and small for gestational age (SGA). Parents responded to questions about household renovation and their children's gestational age and birthweight. In the multivariate logistic regression analyses, household renovation in the year before pregnancy was significantly associated with LBW (sample size: N = 25 813; adjusted odds ratio (OR) with 95% confidence intervals (CIs): 1.23, 1.01-1.50) and Term-LBW (N = 24 823; 1.29, 1.01-1.67). Household renovation during pregnancy was significantly associated with PTB (N = 25 202; 1.28, 1.01-1.69). These significant associations were also found in the two-level (city-child) logistic regression analyses and in the sensitivity analyses among 21 009 children with complete data in all studied variates. Stronger associations were found in certain subgroups. Our findings indicate that household renovation within one year before pregnancy might be a risk factor for LBW and Term-LBW, while household renovation during pregnancy could be a risk factor for PTB.

Pregnancy phthalate metabolite concentrations and infant birth weight by gradations of maternal glucose tolerance

BACKGROUND

Higher birth weight is an important adverse outcome associated with hyperglycemia in pregnancy. Recent studies suggest that phthalate exposure is associated with elevated glucose levels in pregnant women, with implications for higher birth weight in the offspring. No study to date has investigated the association between prenatal phthalate exposure on infant high birth weight accounting for the range of pregnancy glucose levels.

METHODS

A total of 350 women participating in an ongoing pregnancy cohort had data available on urinary phthalate metabolite concentrations at up to four time points across pregnancy. Urinary phthalate metabolites were averaged across pregnancy and log-transformed, specific gravity-adjusted and analyzed in quartiles. Birth weight was examined continuously (in grams), as well as dichotomized as large for gestational age (>90^th percentile). Glucose levels were assessed based on Results from 50-g glucose challenge tests as a part of screening for gestational diabetes conducted at 24-28 weeks gestation, and grouped into 3 categories <120 mg/dL, 120-<140 mg/dL and ≥140 mg/dL. Multivariable linear regression was performed, adjusting for potential confounders in the overall population and stratified by pregnancy glucose levels.

RESULTS

Approximately 20% of infants born to women with glucose levels ≥140 mg/dL were large for gestational age. Average mono-ethyl phthalate (MEP) concentrations were higher among women who had glucose levels ≥140 mg/dL (geometric mean 140.9 μg/L; 95% CI: 91.6-216.8); however, higher MEP concentrations were not associated with higher birth weight. When stratified by maternal glucose levels, there was a suggestive association between higher concentrations of mono-(3-carboxypropyl) phthalate (MCPP) and higher birth weight among women with glucose levels ≥140 mg/dL (adj. birth weight: 569.2 g; 95% CI: 14.1, 1178.2).

CONCLUSIONS

Higher urinary phthalate metabolite concentrations were not significantly associated with higher birth weight. Counter to our hypothesis, women with higher glucose levels and higher urinary phthalate metabolites did not deliver babies with higher birth weight.

Dicyclohexyl phthalate blocks Leydig cell regeneration in adult rat testis

Dicyclohexyl phthalate (DCHP) is a phthalate plasticizer with a ring structure in the alcohol moiety. The objective to the current study was to determine the effects of DCHP on Leydig cell regeneration in the adult rat-testis. Adult male Sprague Dawley rats received intraperitoneally an injection of ethane dimethane sulfone (EDS) to eliminate all Leydig cells in the testis and then were divided into 4 groups of 0 (control), 10, 100, and 1000 mg/kg/day DCHP. Rats were gavaged either vehicle (corn oil, control) or DCHP from post-EDS day 7 to day 21 and 28. On post-EDS day 21 and day 28, rats were euthanized and serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) levels were measured, and Leydig cell number, cell size, gene, and protein expression were evaluated. During the course of exposure, DCHP did not cause the general toxicity to rats. On post-EDS day 21, DCHP significantly increased serum testosterone level at 10 and 100 mg/kg and increased Leydig cell number at 10 mg/kg via stimulating their mitosis. On post-EDS day 28, DCHP lowered serum testosterone levels and Leydig cell number at 1000 mg/kg. DCHP dose-dependently down-regulated the expression of many Leydig cell genes (Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Hsd11b1, and Insl3) and their proteins, especially at 1000 mg/kg. DCHP also lowered the pAKT1/AKT1 and pERK1/2/ERK1/2 ratios. In conclusion, DCHP at low doses (10 and 100 mg/kg) increased Leydig cell number during the initial regeneration and inhibited Leydig cell regeneration during the course of its exposure.

Prenatal phthalate exposure, birth outcomes and DNA methylation of Alu and LINE-1 repetitive elements: A pilot study in China

BACKGROUND

Epigenetic mechanisms, such as altered DNA methylation, may participate in the relationship between prenatal phthalate exposure and adverse birth outcomes.

OBJECTIVE

To explore the mediation effect of DNA methylation in the associations of phthalate exposure before delivery with birth outcomes in a Chinese cohort.

METHODS

Eight phthalate metabolites in maternal urine before delivery and DNA methylation of Alu and long interspersed nucleotide elements (LINE-1) in cord blood were determined among 106 mother-infant pairs. General additive models were used to assess the associations of maternal urinary phthalate metabolites with birth outcomes and DNA methylation; the mediating role of DNA methylation in cord blood was evaluated by mediation analysis.

RESULTS

We found sex-specific associations between prenatal phthalate exposure and birth outcomes and DNA methylation of cord blood. For example, the molar sum of di-2-(ethylhexyl) phthalate (∑DEHPm) metabolites in maternal urine was positively associated with gestational age among male newborns only (P < 0.05); maternal urinary monobenzyl phthalate (MBzP) was negatively associated with Alu methylation among female newborns only (P < 0.05). Mediation analysis did not find that methylation of Alu and LINE-1 to be a direct mediator in the relationships between maternal urinary phthalate metabolites before delivery and birth outcomes.

CONCLUSION

Prenatal exposure to certain phthalates was associated with altered birth outcomes and decreased repetitive element methylation of newborns. However, the altered birth outcomes exerted by prenatal phthalate exposure does not seem to be directly mediated through repetitive element methylation in cord blood.

Evaluating effects of prenatal exposure to phthalates on neonatal birth weight: Structural equation model approaches

BACKGROUND

A large body of evidence has shown that phthalate exposure can lower birth weight in animals and human beings. However, there are only limited data on whether phthalates could affect birth weight directly or indirectly through gestational age and pregnancy syndrome.

OBJECTIVES

To evaluate the effects of prenatal exposure to phthalates on birth weight in neonates and the mediation effects of gestational age and pregnancy syndrome on the association between phthalate exposure and birth weight.

METHODS

In this study, 181 mother-newborn pairs were recruited from Wenzhou city. Maternal urine samples were collected during the third trimester and measured for phthalate metabolites by ESI-MS/MS. Structural equation models (SEMs) were used to evaluate effects of phthalate on birth weight controlling for maternal education, monthly income, nutritional supplements, infant gender, and maternal weight gain per week. The potential mediated effects of phthalate exposure through gestational age and pregnancy syndrome on birth weight were also calculated by structural equation modeling.

RESULTS

After adjusting for potential confounders, urinary mono-phthalate levels (including MMP, MBP, MEHP, MEOHP, and MEHHP) were negatively associated with birth weight. A ten-fold increase in the concentration of MEOHP and MEHHP would be directly associated with lower birth weights (reduced to 124 g and 107 g, respectively). However, MBP had mediated effects on birth weight through gestational age, which was associated with an 85-g reduction in birth weight for every ten-fold increase in exposure. Both direct and mediated effects on birth weight were found in MMP and MEHP. The indirect effects of MMP and MEHP were mediated through gestational age and pregnancy syndrome. Thus, prenatal MMP and MEHP exposures were associated with decrease in birth weight.

CONCLUSIONS

A negative association exists between prenatal phthalate exposure and birth weight in Chinese neonates. In addition to direct pathway, phthalate exposures could affect birth weight through the mediated effects of gestational age and pregnancy syndrome.

Epigenetics and developmental origins of diabetes: correlation or causation?

The incidence of metabolic disorders like type 2 diabetes (T2D) and obesity continue to increase. Although it is evident that the increasing incidence of diabetes confers a global societal and economic burden, the mechanisms responsible for the increased incidence of T2D are not well understood. Extensive efforts to understand the association of early-life perturbations with later onset of metabolic diseases, the founding principle of developmental origins of health and disease, have been crucial in determining the mechanisms that may be driving the pathogenesis of T2D. As the programming of the epigenome occurs during critical periods of development, it has emerged as a potential molecular mechanism that could occur early in life and impact metabolic health decades later. In this review, we critically evaluate human and animal studies that illustrated an association of epigenetic processes with development of T2D as well as intervention strategies that have been employed to reverse the perturbed epigenetic modification or reprogram the naturally occurring epigenetic marks to favor improved metabolic outcome. We highlight that although our understanding of epigenetics and its contribution toward developmental origins of T2D continues to grow, whether epigenetics is a cause, consequence, or merely a correlation remains debatable due to the many limitations/challenges of the existing epigenetic studies. Finally, we discuss the potential of establishing collaborative research efforts between different disciplines, including physiology, epigenetics, and bioinformatics, to help advance the developmental origins field with great potential for understanding the pathogenesis of T2D and developing preventive strategies for T2D.

DNA methylation of imprinted genes in Mexican-American newborn children with prenatal phthalate exposure

AIM

Imprinted genes exhibit expression in a parent-of-origin-dependent manner and are critical for child development. Recent limited evidence suggests that prenatal exposure to phthalates, ubiquitous endocrine disruptors, can affect their epigenetic dysregulation.

MATERIALS & METHODS

We quantified DNA methylation of nine imprinted gene differentially methylated regions by pyrosequencing in 296 cord blood DNA samples in a Mexican-American cohort. Fetal exposure was estimated by phthalate metabolite concentrations in maternal urine samples during pregnancy.

RESULTS

Several differentially methylated regions of imprinted genes were associated with high molecular weight phthalates. The most consistent, positive, and false discovery rate significant associations were observed for MEG3.

CONCLUSION

Phthalate exposure in utero may affect methylation status of imprinted genes in newborn children.

Distribution of Phthalate Metabolites between Paired Maternal-Fetal Samples

Phthalic acid esters (PAEs) are readily metabolized to phthalate metabolites (mPAEs) in the human body. The occurrence of mPAEs in adult human samples is well documented; however, the maternal-fetal transmission of mPAEs has seldom been studied. In this study, 78 paired maternal-fetal samples, including maternal urine (MU), maternal serum (MS), cord serum (CS), and amniotic fluid (AF), were collected from pregnant women in Tianjin, China. Seven mPAEs were detected in MS, CS, and AF, whereas all 11 investigated mPAEs were found in MU. The median concentration of ∑mPAEs was the highest in MU (128 ng/mL, with a range of 20.2-973 ng/mL), and proceeded in the order of CS (44.9, 13.9-315 ng/mL), MS (24.6, 3.75-156 ng/mL), and AF (10.4, 7.69-79.8 ng/mL). The values of ∑mPAEs and several individual mPAEs were significantly correlated between MU and MS, with generally higher concentrations in MU, which indicated that urinary mPAEs is a good indicator of PAEs' exposure in adults. Notably, the median CS:MS ratios of ∑mPAEs (1.58) were higher than 1, indicating that fetuses were exposed to mPAEs before birth. Significant correlations were also observed between MS and CS, which suggested that mPAEs in MS provide an indication of the fetal exposure. This study presents the first systematic analysis of the distribution and transmission of various mPAEs between mothers and fetuses.

Current Knowledge on Endocrine Disrupting Chemicals (EDCs) from Animal Biology to Humans, from Pregnancy to Adulthood: Highlights from a National Italian Meeting

Wildlife has often presented and suggested the effects of endocrine disrupting chemicals (EDCs). Animal studies have given us an important opportunity to understand the mechanisms of action of many chemicals on the endocrine system and on neurodevelopment and behaviour, and to evaluate the effects of doses, time and duration of exposure. Although results are sometimes conflicting because of confounding factors, epidemiological studies in humans suggest effects of EDCs on prenatal growth, thyroid function, glucose metabolism and obesity, puberty, fertility, and on carcinogenesis mainly through epigenetic mechanisms. This manuscript reviews the reports of a multidisciplinary national meeting on this topic.

Phthalate exposure and high blood pressure in adults: a cross-sectional study in China

Widespread phthalate exposure has been recently documented and is hypothesized to increase blood pressure (BP) in humans. However, current studies have provided inconclusive evidence for an association between phthalate exposure and BP. Human epidemiologic studies on the topic remain lacking. Therefore, this study aims to examine the association between serum phthalate concentrations and BP in a Chinese population. We measured several parameters of BP (systolic BP, diastolic BP, total cholesterol, and triglyceride) and the concentrations of 16 phthalates (dimethyl phthalate (DMP), diethyl phthalate, diisobutyl phthalate, dibutyl phthalate (DBP), bis (2-methoxyethyl) phthalate, bis (4-methyl-2-pentyl) phthalate, bis (2-ethoxyethyl) phthalate, diamyl phthalate, dihexyl phthalate, benzyl butyl phthalate, bis (2-nbutoxyethyl) phthalate (DBEP), dicyclohexyl phthalate, bis (2-ethyl hexyl) phthalate (DEHP), diisononyl phthalate, diphenyl phthalate, and di-n-octyl phthalate) in the serum of 474 adults recruited from a primary health care clinic. The relationship between serum phthalate concentrations and BP parameters was assessed with multivariate linear regressions. DBP was the most ubiquitous and dominant contaminant in the study population. The systolic BP of subjects in the median-exposure DEHP group significantly increased by 2.96 mmHg (p < 0.05) relative to that of subjects in the low-exposure group. Significant positive dose-related associations of DMP and DBEP with the levels of total cholesterol in serum (p for trend < 0.05) were also found. These associations persisted even when considering exposure to multiple phthalates. Our results suggested that phthalate exposure might increase BP in adults. However, our findings warrant further studies in a larger and more general population.

OBGYN screening for environmental exposures: A call for action

Background

Prenatal exposures have known adverse effects on maternal and neonatal outcomes. Professional societies recommend routine screening for environmental, occupational, and dietary exposures to reduce exposures and their associated sequelae.

Objective

Our objective was to determine the frequency of environmental exposure screening by obstetricians and gynecologists (OBGYNs) at initial patient visits.

Study design

Practicing OBGYNs were approached at the University of Colorado and by social media. The survey instrument queried demographics, environmental literacy, and screening practices. Statistical analysis was performed using Chi-square and two-sample t-test.

Results

We received 312 online survey responses (response rate of 12%). Responding OBGYNs were predominantly female (96%), board-certified (78%), generalists (65%) with a mean age of 37.1 years. Fewer than half of physicians screened for the following factors: occupational exposures, environmental chemicals, air pollution, pesticide use, personal care products, household cleaners, water source, use of plastics for food storage, and lead and mercury exposure. Eighty five percent of respondents reported that they did not feel comfortable obtaining an environmental history and 58% respondents reported that they performed no regular screening of environmental exposures. A higher frequency of screening was associated with > 4 years of practice (p = 0.001), and having read the environmental committee opinion (p = <0.001).

Conclusion

The majority of OBGYNs did not incorporate screening for known environmental exposures into routine practice. Reading the environmental committee opinions was strongly and significantly associated with a higher rate of screening. Improving physician comfort in counseling patients may enhance screening for exposures that affect reproductive health.

Exposure to Phthalate, an Endocrine Disrupting Chemical, Alters the First Trimester Placental Methylome and Transcriptome in Women

Phthalates are known endocrine disruptors and associated with decreased fecundity, pregnancy loss, and adverse obstetrical outcomes, however the underlying mechanisms remain to be established. Environmental factors can influence gene expression and cell function by modifying epigenetic marks, impacting the developing embryo as well as future generations of offspring. The impact of phthalates on placental gene methylation and expression is largely unknown. We studied the effect of maternal phthalate exposure on the human placental DNA methylome and transcriptome. We determined epigenome-wide DNA methylation marks (Illumina Infinium Human Methylation 850k BeadChip) and gene expression (Agilent whole human genome array) associated with phthalate exposure in first trimester placenta. Integrative genomic analysis of candidate genes was performed to define gene methylation-expression relationships. We identified 39 genes with significantly altered methylation and gene expression in the high phthalate exposure group. Most of these relationships were inversely correlated. This analysis identified epidermal growth factor receptor (EGFR) as a critical candidate gene mediating the effects of phthalates on early placental function. Although additional studies are needed to determine the functional consequences of these changes, our findings are consistent with the model that phthalates impact placental function by modulating the expression of critical placental genes through epigenetic regulation.

Evidence of high di(2-ethylhexyl) phthalate (DEHP) exposure due to tainted food intake in Taiwanese pregnant women and the health effects on birth outcomes

The contamination of a clouding agent with di(2-ethylhexyl) phthalate (DEHP), a substitute emulsifier-containing compound used in a variety of foods was announced on May 23, 2011. The aims of this study were as follows (1) compare the urine phthalates (PAE) metabolites concentration and estimate the daily intake (DI) of PAEs in pregnant women before and after the tainted food scandal and (2) examine the effect of relatively high PAEs exposure on birth outcome. One-hundred twelve pregnant women in Northern Taiwan participated in this study from March to December 2010, i.e., before the tainted food scandal. After the tainted food scandal, we collected 69, 73, and 180 urine specimens (January 2013 to August 2014) from women whom were in their first, second, and third trimesters of pregnancy, respectively. We measure urinary DEHP metabolite concentrations to estimate the DI of DEHP and the hazard quotient (HQ) of subjects. This was the first study to assess the effects of DEHP-tainted food scandal exposure in pregnant women across the three trimesters of pregnancy. After the tainted food report, the concentrations of urine PAE metabolite were significantly decreased, especially those of DEHP metabolites. Based on different reference limit values, the percentages of pregnant women whose HQ_DEHP value exceeded the limit ranged from 0.53% to 8.93%. Despite this low frequency, the higher ΣPAE exposure during the second trimester may significantly increase the risk of relatively low birth height compared to the lower exposure group (β=-0.63 (-1.20 to -0.06)). Our results support the hypothesis that exposure to relatively high concentrations of DEHP in pregnant Taiwanese women may have an adverse effect on birth outcomes. The percentage of subjects whose exposure level exceeded the exposure limit was low; however, high PAEs exposure appears to be significantly associated with birth outcomes. Therefore, we suggest that reference dose for PAEs should be revised.

Household environmental exposures during gestation and birth outcomes: A cross-sectional study in Shanghai, China

Several studies have reported that certain aspects of the household environments are associated with adverse birth outcomes, but associations have been inconsistent. Few of these studies have been conducted in China. During 2011-2012, we conducted a retrospective cross-sectional study and collected 13,335 parents-reported questionnaires for 4-6-year-olds children in Shanghai, China. We investigated associations of household environmental factors (environmental tobacco smoke (ETS), cooking fuel, dampness, pet-keeping, and home renovation) during gestation with preterm birth (PTB, gestational age<37weeks), low birth weight (LBW, birth weight<2500g), term low birth weight (T-LBW, LBW when the gestational age was ≥37weeks), and small for gestational age (SGA, birth weight<10th percentile of birth weight for gestational age). A total of 4.1% children were premature; 2.9% had LBW and 1.6% had T-LBW; 8.1% were SGA. In the multiple logistic regression analyses, home renovation during gestation was associated with PTB (adjusted odds ratio (OR), 95% confidence intervals (CI): 1.68, 1.11-2.54) and LBW (1.64, 0.99-2.72). Paternal smoking was associated with PTB (1.18, 0.98-1.43). No significant associations were found for SGA. Neither household dampness nor cooking fuel were significantly associated with birth outcomes. For boys, paternal smoking was associated with PTB (1.31, 1.02-1.69); home renovation during gestation was associated with PTB (2.14, 1.27-3.61) and LBW (2.19, 1.09-4.43). Among children whose mothers were ≥34-year-olds during gestation, paternal smoking (1.73, 1.04-2.76) and home renovation during gestation (1.80, 1.18-2.76) was associated with PTB. Our findings demonstrate that home renovation and ETS during gestation may be risk factors for adverse birth outcomes. Associations of these factors with adverse birth outcomes appear to be stronger in boys and among mothers older than 34years during gestation. Home renovation and ETS exposure should be avoided during gestation, especially for pregnancies with male fetuses and older pregnant women.

Effects of the phthalate exposure during three gestation periods on birth weight and their gender differences: A birth cohort study in China

Phthalate has been widely used as a type of plasticiser in various consuming products in daily life. Recent studies have suggested that prenatal phthalate exposure may have adverse effects on fetal development. We aimed to identify the effects of in utero phthalate exposure on birth weight (BW). We evaluated a birth cohort comprising 3474 pregnant women and their single infants; 3103, 2975 and 2838 urine samples were collected in the first, second and third trimesters, respectively. Phthalate metabolites included monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEHHP), and mono-(2-ethyl-5-hydroxylhexyl) phthalate (MEOHP), which were analysed in the urine by using high performance liquid chromatography-tandem mass spectrometry. Mixed linear model was used in the statistical analysis. Generally, MMP and MEP exposure during pregnancy was associated with decreased birth weight of infants (MMP, β=-12.192, p=0.009; MEP, β=-11.876, p=0.014). Hierarchical analysis found that MMP and MEOHP exposure was associated with decreased infants' birth weight only in low birth weight groups (MMP, β=-42.538, p=0.005; MEOHP, β=-63.224, p=0.008); MEHP and MEHHP exposure was associated with decreased infants' birth weight in both low birth weight group (MEHP, β=-42.348, p=0.035; MEHHP, β=-50.485, p=0.006) and high birth weight group (MEHP, β=-16.580, p=0.034; MEHHP, β=-18.009, p=0.040), MBP and MEHP exposure were associated with increased infants' birth weight in male NBW group (MBP, β=10.438, p=0.039; MEHP, β=13.223, p=0.017). Moreover, the effect has sex difference. The reduction of birth weight associated with MEHP and MEOHP exposure was stronger in male infants, while MMP and MEP exposure was more significant in female infants.

Prevalence and predictors of phthalate exposure in pregnant women in Charleston, SC

Phthalates are plasticizers commonly detected in human urine due to widespread exposure from PVC plastics, food packaging, and personal care products. Several phthalates are known antiandrogenic endocrine disruptors, which raises concern for prenatal exposure during critical windows of fetal development. While phthalate exposure is ubiquitous, certain demographics are subject to greater or lesser exposure. We sampled urine from 378 pregnant women during the second trimester of gestation living in Charleston, SC, and measured eight urinary phthalate metabolites as biomarkers of phthalate exposure: monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), and monomethyl phthalate (MMP). Demographic data was collected from questionnaires administered at the time of specimen collection. All phthalate metabolites were detected in over 93% of urine samples. On average, concentrations were highest for MEP (median = 47.0 ng/mL) and lowest for MMP (median = 1.92 ng/mL). Sociodemographic characteristics associated with elevated phthalate concentrations included being unmarried, less educated, having a low income, high body mass index (BMI), and/or being African American. After racial stratification, age, BMI, education, and income were significantly associated with phthalate concentrations in African American women. Marital status was associated with phthalate concentrations in Caucasian women only, with greater concentrations of MBP, MEHHP, MiBP, and MMP in unmarried versus married women. Results of this cross-sectional study provide evidence for significant racial and demographic variations in phthalate exposure.

Relationship between maternal phthalate exposure and offspring size at birth

Research findings on effects of prenatal phthalate exposure on fetal growth were inconsistent. Increasing evidence from animal studies has indicated a potential sex-specific effect of phthalates on fetal growth, but the current human data was limited. In this study, we aimed to estimate the relationships between maternal phthalate exposure and infant birth size. Six major phthalate metabolite levels of urine samples were measured among pregnant women (n=1002) from the Healthy Baby Cohort (HBC), China. The associations between urinary phthalate metabolites levels and birth size (birth weight, birth length, birth weight z-scores and ponderal index) were estimated using linear regression models. In boys, the ln-transformed di-2-ethylhexyl phthalate (DEHP) metabolite levels were significantly associated with increased birth weight and birth weight z-scores. Additionally, each ln-unit increase in mono-(2-ethyl-5-carbox-ypentyl) phthalate (MECPP) was associated with a 0.25kg/m³ [95% confidence interval (CI): 0.03, 0.47] increase in ponderal index in boys. However, we did not observe any significant association of maternal phthalate metabolite levels with any of the outcomes in girls. Our data suggested potential sex-specific associations of maternal phthalate exposure with increased birth weight and ponderal index, which were merely apparent in boys.

Gestational exposure to endocrine disrupting chemicals in relation to infant birth weight: a Bayesian analysis of the HOME Study

BACKGROUND

Pregnant women are exposed to a mixture of endocrine disrupting chemicals (EDCs). Gestational EDC exposures may be associated with changes in fetal growth that elevates the risk for poor health later in life, but few studies have examined the health effects of simultaneous exposure to multiple chemicals. This study aimed to examine the association of gestational exposure to five chemical classes of potential EDCs: phthalates and bisphenol A, perfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) with infant birth weight.

METHODS

Using data from the Health Outcomes and Measures of Environment (HOME) Study, we examined 272 pregnant women enrolled between 2003-2006. EDC concentrations were quantified in blood and urine samples collected at 16 and 26 weeks gestation. We used Bayesian Hierarchical Linear Models (BHLM) to examine the associations between newborn birth weight and 53 EDCs, 2 organochlorine pesticides (OPPs) and 2 heavy metals.

RESULTS

For a 10-fold increase in chemical concentration, the mean differences in birth weights (95% credible intervals (CI)) were 1 g (-20, 23) for phthalates, -11 g (-52, 34) for PFAS, 0.2 g (-9, 10) for PCBs, -4 g (-30, 22) for PBDEs, and 7 g (-25, 40) for OCPs.

CONCLUSION

Gestational exposure to phthalates, PFAS, PCBs, PBDEs, OCPs or OPPs had null or small associations with birth weight. Gestational OPP, Pb, and PFAS exposures were most strongly associated with lower birth weight.

Peroxisome proliferator activated receptor gamma in human placenta may mediate the adverse effects of phthalates exposure in pregnancy

Peroxisome-proliferator activated receptor gamma (PPARG) in placenta play an important role in pregnancy. Our previous study showed that it mediated the effects of phthalates on placental mRNA expression of estrogen synthetases in rats. To assess the effects of phthalate exposure on PPARG placental expression, and the contribution of PPARG to the effects of phthalates in human. 207 healthy pregnant women were recruited and their cord blood and placenta were collected upon delivery. Three phthalates, estrogens in cord blood and protein expression of PPARG in placenta were measured. Linear regression were used to analyze the relationship between phthalates exposure, PPARG expression and hormones. Phthalate levels in cord blood were positively associated with PPARG protein expression in placenta (p<0.05), whereas estrogens in cord blood were negatively associated with phthalate levels and PPARG expression (p<0.05). This study shows that PPARG in placenta may mediate the adverse effects of phthalates on pregnancy in human.

Adipose Tissue as a Site of Toxin Accumulation

We examine the role of adipose tissue, typically considered an energy storage site, as a potential site of toxicant accumulation. Although the production of most persistent organic pollutants (POPs) was banned years ago, these toxicants persist in the environment due to their resistance to biodegradation and widespread distribution in various environmental forms (e.g., vapor, sediment, and water). As a result, human exposure to these toxicants is inevitable. Largely due to their lipophilicity, POPs bioaccumulate in adipose tissue, resulting in greater body burdens of these environmental toxicants with obesity. POPs of major concern include polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), and polybrominated biphenyls and diphenyl ethers (PBBs/PBDEs), among other organic compounds. In this review, we (i) highlight the physical characteristics of toxicants that enable them to partition into and remain stored in adipose tissue, (ii) discuss the specific mechanisms of action by which these toxicants act to influence adipocyte function, and (iii) review associations between POP exposures and the development of obesity and diabetes. An area of controversy relates to the relative potential beneficial versus hazardous health effects of toxicant sequestration in adipose tissue. © 2017 American Physiological Society. Compr Physiol 7:1085-1135, 2017.

Urinary concentrations of phthalate metabolites in early pregnancy associated with clinical pregnancy loss in Chinese women

Limited evidence revealed conflicting results on relationship between phthalate exposure and clinical pregnancy loss (gestational weeks >6). A prospective cohort study in Chinese pregnant women (n = 3220) was conducted to investigate the association between urinary phthalate metabolites and clinical pregnancy loss (gestational weeks 6 to 27; n = 109). Morning urine samples during gestational weeks 5 to 14 (mean 10.42) were collected to measure monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). The concentrations of low- and high-molecular weight phthalate metabolites (ΣLMWP <250 Da and ΣHMWP >250 Da) were calculated. Adjusted logistic regression models showed increased risks of clinical pregnancy loss in women with higher creatinine- normalized concentrations of MEP, MBP, MEOHP, MEHHP, ΣLMWP and ΣHMWP. Stratified analysis by gestational weeks (10 weeks) of miscarriage indicated positive associations of MEP, MEOHP, MEHHP and ΣHMWP with embryonic loss (during gestational weeks 6 to 10). The only association of foetal loss (during gestational weeks 11 to 27) was observed with MEHHP. Our findings suggested that Chinese women who were exposed to phthalates during early pregnancy had an increased risk of clinical pregnancy loss, especially embryonic loss.

Season-dependent concentrations of urinary phthalate metabolites among Chinese pregnant women: Repeated measures analysis

In utero exposure to phthalates may have adverse effects on pregnant women and their offsprings. Therefore, the exposure level of these substances among individuals, particularly among sensitive population, is of concern. The objective of the present study is to characterize urinary concentrations of phthalate metabolites at multiple time points during pregnancy in Chinese women. A total of 3455 pregnant women were included from Ma'anshan Birth Cohort in China. Spot urine samples in the morning (8:00-10:00) and questionnaires were obtained at three separate visits (approximately in 10, 26, and 34 gestational weeks). Seven phthalate metabolites from urine samples were analyzed, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). Geometric means of concentrations were ranged from 0.05 to 41.0ng/mL for all the metabolites mentioned above. No individual exposure level was above the 95th percentiles for all the seven phthalates. On the three separate visits, 0.5%, 0.9% and 1.2% of the participants had coexposure to above the 75th percentiles for all metabolites. Taken these visits together, a total of 29 urine samples had concentrations above the 95th percentiles, while 3.0%-5.6% of urine levels were above 75th percentiles for at least one specific phthalate metabolite. We observed moderate intraclass correlation coefficients (ICCs) ranging from 0.44 to 0.56 for MBzP, MEHP and MEP, and lower ICCs, from 0.28 to 0.32, for MMP, MBP, MEOHP and MEHHP. Sampling season was associated with concentrations of all phthalate metabolites, showing heavier exposure was more likely to occur during summer. In summary, phthalate exposure is prevalent in Chinese pregnant women. However, throughout pregnancy coexposure to multiple phthalates at the upper percentile of exposure is infrequent. Mild to moderate temporal stability indicates that a single measurement in spot urine collected in the morning (8:00-10:00) seems not enough to describe throughout pregnancy phthalate exposure. Urinary levels vary by sampling seasons, which should be taken into consideration in future analyses.

Cumulative risk assessment of phthalates associated with birth outcomes in pregnant Chinese women: A prospective cohort study

A prospective cohort study of a Chinese population of mother-neonate pairs (n = 3103) was conducted to investigate the relationship between the cumulative hazard index (HI) of combined diethyl phthalate (DEP), dibutyl phthalate (DBP), dibenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) exposure and birth outcomes. The estimated HI for phthalates was based on phthalate metabolite concentrations in urine collected between 5th and 14th gestational weeks. The median HI values according to the European Food Safety Authority tolerable daily intake (HI_TDI) and U.S. Environmental Protection Agency reference dose (HI_RfD) were 0.358 and 0.187, respectively. A total of 16.3% and 1.9% of the women exhibited HI_TDI and HI_RfD exceeding the value of one, respectively. In unadjusted models, the categories (low < P₂₅, median P₂₅-P₅₀, high > P₇₅) of HI_TDI were associated with decreased birth weight (β = -26.34 g, p = 0.021) and head circumference (β = -0.09 cm, p = 0.029), whereas those for HI_RfD were negatively associated with birth weight (β = -31.74 g, p = 0.005), birth length (β = -0.11 cm, p = 0.032), head circumference (β = -0.13 cm, p = 0.003) and chest circumference (β = -0.10 cm, p = 0.021) in all neonates. Adjustment for potential confounders revealed that HI_RfD was inversely associated with head circumference (β = -0.10 cm, p = 0.020). Stratification by gender indicated that HI_RfD was associated with decreased birth length (β = -0.17 cm, p = 0.041) in infant boys and HI_TDI was associated with decreased birth weight (β = -33.12 g, p = 0.036) and head circumference (β = -0.13 cm, p = 0.027) in girls. This is the first study on the cumulative risk assessment of phthalate exposures in pregnant Chinese women. We found that the HI values of multiple phthalate co-exposure were sex-specifically related to birth outcomes.

Prenatal di-2-ethylhexyl phthalate exposure and cord blood adipokine levels and birth size: The Hokkaido study on environment and children's health

Di-2-ethylhexyl phthalate (DEHP) is one of the most widely used phthalates. Metabolites of DEHP are detectable in majority of the population. Findings on adverse health outcomes, particularly birth weight in association with prenatal exposure to DEHP remain equivocal. Besides, there is insufficient evidence to address influence on metabolic function from epidemiological studies. Thus, our objective was to investigate cord blood adipokine levels and birth size in association with prenatal DEHP exposure in prospective birth cohort study. Mono-2-methylhexyl phthalate (MEHP), primary metabolite of DEHP was determined as exposure by using maternal blood sample of 3rd trimester. Leptin and adiponectin levels in cord blood were measured as markers of metabolic function. Birth weight and length were obtained from birth record. Association between maternal MEHP levels and cord blood adiponectin and leptin levels, birth weight and ponderal index (PI) were examined for 167 mother-child pairs who had both MEHP and cord blood adipokine measurements. The median MEHP level was 8.81ng/ml and the detection rate was 100%. There was no sex difference in MEHP levels. Both leptin and adiponectin levels were higher in girls than in boys. MEHP level was positively associated with adiponectin level among boys and was negatively associated with leptin level among girls. MEHP level were negatively associated with PI only in girls and this could be due to decreased leptin level. This study suggested that prenatal DEHP exposure may be associated with cord blood adipokine and birth size. The influence potentially be sex-specific and could be more significant in girls.

A global assessment of phthalates burden and related links to health effects

Phthalates are ubiquitous environmental contaminants which are used in industry as plasticizers and additives in cosmetics. They are classified as Endocrine Disrupting Chemicals (EDCs) which impair the human endocrine system inducing fertility problems, respiratory diseases, childhood obesity and neuropsychological disorders. The aim of this review is to summarize the current state of knowledge on the toxicity that phthalates pose in humans based on human biomonitoring studies conducted over the last decade. Except for conventional biological matrices (such as urine and serum), amniotic fluid, human milk, semen, saliva, sweat, meconium and human hair are also employed for the estimation of exposure and distribution of pollutants in the human body, although data are not enough yet. Children are highly exposed to phthalates relative to adults and in most studies children's daily intake surpasses the maximum reference dose (RfD) set from US Environmental Protection Agency (US EPA). However, the global trend is that human exposure to phthalates is decreasing annually as a result of the strict regulations applied to phthalates.

A systematic review on the adverse health effects of di-2-ethylhexyl phthalate

Di (ethylhexyl) phthalate (DEHP) is a global environmental pollutant. This study aims to systematically review the literature on health effects of exposure to DEHP including effects on reproductive health, carcinogenesis, pregnancy outcome, and respiratory system. The literature search was done through Scopus, ISI Web of Science, Google Scholar, PubMed, Medline, and the reference lists of previous review articles to identify relevant articles published to June 2016 in each subject area. The inclusion criteria were as follows: original research, cross-sectional studies, case-control studies, cohort studies, interventional studies, and review articles. Both human and animal studies were included. The search was limited to English language papers. Conference papers, editorials, and letters were not included. The systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Overall, 152 of the 407 papers met the inclusion criteria. We provided an up-to-date comprehensive and critical assessment of both human and animal studies undertaken to explore the effects of DEHP. It revealed that in experimental studies, exposure to DEHP mainly targeted the reproductive, neurodevelopment, and respiratory systems. Human studies reported that exposure to this contaminant had carcinogenic effects and influenced neurodevelopment in early life. This systematic review underscored the adverse health effects of DEHP for pregnant women and the pediatric age group. It summarizes different response of humans and experimental animals to DEHP exposure, and some suggested underlying mechanisms.

Occupational Exposure to Endocrine-Disrupting Chemicals and Birth Weight and Length of Gestation: A European Meta-Analysis

BACKGROUND

Women of reproductive age can be exposed to endocrine-disrupting chemicals (EDCs) at work, and exposure to EDCs in pregnancy may affect fetal growth.

OBJECTIVES

We assessed whether maternal occupational exposure to EDCs during pregnancy as classified by application of a job exposure matrix was associated with birth weight, term low birth weight (LBW), length of gestation, and preterm delivery.

METHODS

Using individual participant data from 133,957 mother-child pairs in 13 European cohorts spanning births from 1994 through 2011, we linked maternal job titles with exposure to 10 EDC groups as assessed through a job exposure matrix. For each group, we combined the two levels of exposure categories (possible and probable) and compared birth outcomes with the unexposed group (exposure unlikely). We performed meta-analyses of cohort-specific estimates.

RESULTS

Eleven percent of pregnant women were classified as exposed to EDCs at work during pregnancy, based on job title. Classification of exposure to one or more EDC group was associated with an increased risk of term LBW [odds ratio (OR) = 1.25; 95% CI: 1.04, 1.49], as were most specific EDC groups; this association was consistent across cohorts. Further, the risk increased with increasing number of EDC groups (OR = 2.11; 95% CI: 1.10, 4.06 for exposure to four or more EDC groups). There were few associations (p < 0.05) with the other outcomes; women holding job titles classified as exposed to bisphenol A or brominated flame retardants were at higher risk for longer length of gestation.

CONCLUSION

Results from our large population-based birth cohort design indicate that employment during pregnancy in occupations classified as possibly or probably exposed to EDCs was associated with an increased risk of term LBW. Citation: Birks L, Casas M, Garcia AM, Alexander J, Barros H, Bergström A, Bonde JP, Burdorf A, Costet N, Danileviciute A, Eggesbø M, Fernández MF, González-Galarzo MC, Gražulevičienė R, Hanke W, Jaddoe V, Kogevinas M, Kull I, Lertxundi A, Melaki V, Andersen AM, Olea N, Polanska K, Rusconi F, Santa-Marina L, Santos AC, Vrijkotte T, Zugna D, Nieuwenhuijsen M, Cordier S, Vrijheid M. 2016. Occupational exposure to endocrine-disrupting chemicals and birth weight and length of gestation: a European meta-analysis. Environ Health Perspect 124:1785-1793; http://dx.doi.org/10.1289/EHP208.

Maternal exposure to di-2-ethylhexylphthalate and adverse delivery outcomes: A systematic review

Adverse pregnancy outcomes, including preterm delivery, short gestational age, and abnormal birth weight, remain a public health concern. The evidence on the association of the most common phthalate, di-2-ethylhexyl phthalate (DEHP) with adverse pregnancy outcomes remains equivocal. This systematic review summarizes published studies that investigated the association of DEHP with preterm delivery, gestational age, and birthweight. A comprehensive literature search found 15 relevant studies, most of which evaluated more than one outcome (four studies for preterm delivery, nine studies for gestational age, and ten studies for birthweight). Studies varied greatly with respect to study design, exposure assessment, analytical methods, and direction of the associations. We identified important methodological concerns which could have resulted in selection bias and exposure misclassification and contributed to null findings and biased associations. Given limitations of the previous studies discussed in this review, more thorough investigation of these associations is warranted to advance our scientific knowledge.

Third trimester phthalate exposure is associated with DNA methylation of growth-related genes in human placenta

Strong evidence implicates maternal phthalate exposure during pregnancy in contributing to adverse birth outcomes. Recent research suggests these effects might be mediated through the improper regulation of DNA methylation in offspring tissue. In this study, we examined associations between prenatal phthalate exposure and DNA methylation in human placenta. We recruited 181 mother-newborn pairs (80 fetal growth restriction newborns, 101 normal newborns) in Wenzhou, China and measured third trimester urinary phthalate metabolite concentrations and placental DNA methylation levels of IGF2 and AHRR. We found urinary concentrations of mono (2-ethyl-5- hydroxyhexyl) phthalate (MEHHP), and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) were significantly inversely associated with placental IGF2 DNA methylation. The associations were much more evident in fetal growth restriction (FGR) newborns than those in normal newborns. These findings suggest that changes in placental DNA methylation might be part of the underlying biological pathway between prenatal phthalate exposure and adverse fetal growth.

Effects of early exposure to phthalates and bisphenols on cardiometabolic outcomes in pregnancy and childhood

Pregnant women are exposed to various chemicals, including endocrine-disrupting chemicals (EDCs) such as phthalates and bisphenols. Increasing evidence suggests that early life exposures to phthalates and bisphenols may contribute to cardiometabolic risks. The aim of this narrative review was to summarize current knowledge of the effects of fetal and childhood exposure to phthalates and bisphenols on child growth and child cardiometabolic outcomes and the effects on maternal outcomes. In total, 54 studies were identified and included. The majority of studies found effects of phthalates and bisphenols on maternal, child growth, and cardiometabolic outcomes. Currently results suggest that early life exposure to phthalates and bisphenols may have a substantial influence on perinatal and postnatal cardiometabolic programming. In a large part of the investigated outcomes studies show contradictory results. However, the majority of the existing evidence is based on non-cohort studies with single samples neglecting time-variant effects and complicating conclusions regarding causal inference. More studies are needed investigating the mechanisms and its potential interactions.