Serum Phthalate and Triclosan Levels Have Opposing Associations With Risk Factors for Gestational Diabetes Mellitus

Maternal exposure to bisphenols, phthalates, perfluoroalkyl acids, and trace elements and their associations with gestational diabetes mellitus in the APrON cohort

The increasing global prevalence of gestational diabetes mellitus (GDM) has been hypothesized to be associated with maternal exposure to environmental chemicals. Here, among 420 women participating in the Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study, we examined associations between GDM and second trimester blood or urine concentrations of endocrine disrupting chemicals (EDCs): bisphenol-A (BPA), bisphenol-S (BPS), twelve phthalate metabolites, eight perfluoroalkyl acids (PFAAs), and eleven trace elements. Fifteen (3.57%) of the women were diagnosed with GDM, and associations between the environmental chemical exposures and GDM diagnosis were examined using multiple logistic and LASSO regression analyses in single- and multi-chemical exposure models, respectively. In single chemical exposure models, BPA and mercury were associated with increased odds of GDM, while a significant inverse association was observed for zinc. Double-LASSO regression analysis selected mercury (AOR: 1.51, CI: 1.12-2.02), zinc (AOR: 0.017, CI: 0.0005-0.56), and perfluoroundecanoic acid (PFUnA), a PFAAs, (AOR: 0.43, CI: 0.19-0.94) as the best predictors of GDM. The combined data for this Canadian cohort suggest that second trimester blood mercury was a robust predictor of GDM diagnosis, whereas blood zinc and PFUnA were protective factors. Research into mechanisms that underlie the associations between mercury, zinc, PFUnA, and the development of GDM is needed.

Cohort profile: the Environmental Reproductive and Glucose Outcomes (ERGO) Study (Boston, Massachusetts, USA) - a prospective pregnancy cohort study of the impacts of environmental exposures on parental cardiometabolic health

PURPOSE

Pregnancy and the postpartum period are increasingly recognised as sensitive windows for cardiometabolic disease risk. Growing evidence suggests environmental exposures, including endocrine-disrupting chemicals (EDCs), are associated with an increased risk of pregnancy complications that are associated with long-term cardiometabolic risk. However, the impact of perinatal EDC exposure on subsequent cardiometabolic risk post-pregnancy is less understood. The Environmental Reproductive and Glucose Outcomes (ERGO) Study was established to investigate the associations of environmental exposures during the perinatal period with post-pregnancy parental cardiometabolic health.

PARTICIPANTS

Pregnant individuals aged ≥18 years without pre-existing diabetes were recruited at <15 weeks of gestation from Boston, Massachusetts area hospitals. Participants completed ≤4 prenatal study visits (median: 12, 19, 26, 36 weeks of gestation) and 1 postpartum visit (median: 9 weeks), during which we collected biospecimens, health histories, demographic and behavioural data, and vitals and anthropometric measurements. Participants completed a postpartum fasting 2-hour 75 g oral glucose tolerance test. Clinical data were abstracted from electronic medical records. Ongoing (as of 2024) extended post-pregnancy follow-up visits occur annually following similar data collection protocols.

FINDINGS TO DATE

We enrolled 653 unique pregnancies and retained 633 through delivery. Participants had a mean age of 33 years, 10% (n=61) developed gestational diabetes and 8% (n=50) developed pre-eclampsia. Participant pregnancy and postpartum urinary phthalate metabolite concentrations and postpartum glycaemic biomarkers were quantified. To date, studies within ERGO found higher exposure to phthalates and phthalate mixtures, and separately, higher exposure to radioactive ambient particulate matter, were associated with adverse gestational glycaemic outcomes. Additionally, certain personal care products used in pregnancy, notably hair oils, were associated with higher urinary phthalate metabolite concentrations, earlier gestational age at delivery and lower birth weight.

FUTURE PLANS

Future work will leverage the longitudinal data collected on pregnancy and cardiometabolic outcomes, environmental exposures, questionnaires, banked biospecimens and paediatric data within the ERGO Study.

The Relationship between Phthalates and Diabetes: A Review

Since the beginning of their production, in the 1930s, phthalates have been widely used in the plastics industry to provide durability and elasticity to polymers that would otherwise be rigid, or as solvents in hygiene and cosmetic products. Taking into account their wide range of applications, it is easy to understand why their use has been increasing over the years, making them ubiquitous in the environment. This way, all living organisms are easily exposed to these compounds, which have already been classified as endocrine disruptor compounds (EDC), affecting hormone homeostasis. Along with this increase in phthalate-containing products, the incidence of several metabolic diseases has also been rising, namely diabetes. That said, and considering that factors such as obesity and genetics are not enough to explain this substantial increase, it has been proposed that the exposure to environmental contaminants may also be a risk factor for diabetes. Thus, the aim of this work is to review whether there is an association between the exposure to phthalates and the development of the several forms of diabetes mellitus, during pregnancy, childhood, and adulthood.

Phthalates' exposure leads to an increasing concern on cardiovascular health

Being an essential component in the plastics industry, phthalates are ubiquitous in the environment and in everyday life. They are considered environmental contaminants that have been classified as endocrine-disrupting compounds. Despite di-2-ethylhexyl phthalate (DEHP) being the most common plasticizer and the most studied to date, there are many others that, in addition to being widely used in the plastic, are also applied in the medical and pharmaceutical industries and cosmetics. Due to their wide use, phthalates are easily absorbed by the human body where they can disrupt the endocrine system by binding to molecular targets and interfering with hormonal homeostasis. Thus, phthalates exposure has been implicated in the development of several diseases in different age groups. Collecting information from the most recent available literature, this review aims to relate human phthalates' exposure with the development of cardiovascular diseases throughout all ages. Overall, most of the studies presented demonstrated an association between phthalates and several cardiovascular diseases, either from prenatal or postnatal exposure, affecting foetuses, infants, children, young and older adults. However, the mechanisms underlying these effects remain poorly explored. Thus, considering the cardiovascular diseases incidence worldwide and the constant human exposure to phthalates, this topic should be extensively studied to understand the mechanisms involved.

Environmental pollutants exposure and gestational diabetes mellitus: Evidence from epidemiological and experimental studies

Except for known sociodemographic factors, long-term exposure to environmental pollutants has been shown to contribute to the development of gestational diabetes mellitus (GDM), but the conclusions remain controversial. To provide a comprehensive overview of the association between environmental pollutants and GDM, we performed a systematic review and meta-analysis. Several electronic databases (PubMed, Embase, Web of Science, Medline and Cochrane) were searched for related epidemiological and experimental studies up to September 2022. For epidemiological studies, a meta-analysis was carried out to appraise the effect of environmental pollutants, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), per- and polyfluoroalkyl substances (PFASs), phenols, phthalates (PAEs), polybrominated diphenyl ethers (PBDEs) and parabens exposure on GDM. Moreover, we also summarized possible biological mechanisms linking pollution exposure and GDM based on the included experimental studies. A total of 80 articles were enrolled, including 38 epidemiological studies and 42 experimental studies. Meta-analysis results showed that exposure to PAEs [OR (95%CI) = 1.07 (1.00, 1.14)], PFASs [OR (95%CI) = 1.10 (1.01, 1.19)], as well as PCBs [OR (95%CI) = 1.18 (1.02, 1.36)] and PBDEs [OR (95%CI) = 1.33 (1.17, 1.50)] significantly increased the risk of GDM, but no significant effects were found for phenols, OCPs, and parabens. In addition, experimental studies suggested that the potential biological mechanisms of environmental pollutants contributing to GDM may involve insulin resistance, β-cell dysfunction, neurohormonal dysfunction, inflammation, oxidative stress, epigenetic modification, and alterations in gut microbiome. In conclusion, long-term environmental pollutants exposure may induce the development of GDM, and there may be a synergistic effect between the homologs. However, studies conducted on the direct biological link between environmental pollutants and GDM were few. More prospective studies and high-quality in vivo and in vitro experiments were needed to investigate the specific effects and mechanisms.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Effects of exposure to phthalate during early pregnancy on gestational diabetes mellitus: a nested case-control study with propensity score matching

Owing to the complexity of phthalates (PAEs) components and the diversity of their sources, the health hazards of their metabolites to pregnant women remain unclear. This study aimed to explore the relationship between exposure to PAEs during early pregnancy and gestational diabetes mellitus (GDM) in rural pregnant women. We assessed pregnant women with (n = 338) or without (n = 3082) GDM from the ongoing Zunyi Birth Cohort. Participants' urine samples were collected to measure the levels of 10 metabolites of PAEs. GDM was diagnosed using the 75-g oral glucose tolerance test at 24-28 weeks of gestation. We adopted propensity score matching based on GDM-related factors and pregnant women's backgrounds to establish two groups of 338 patients: those with or without GDM. In the cohort, we included 5734 pregnant women; 519 of them developed GDM, yielding a GDM incidence rate of 9.05%. Urinary concentrations of monooctyl phthalate (MOP), mono-benzyl phthalate (MBzP), mono(2-ethyl-5-oxyhexyl) phthalate (MEOHP), and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP) during early pregnancy were significantly associated with GDM (P < 0.05). Logistic regression models revealed that MEOHP in the urine was positively associated with GDM (odds ratio [OR] = 1.55; 95% confidence interval [CI]: 1.00-2.39). Furthermore, restricted cubic spline models revealed that urine MEOHP concentrations greater than 15.6 μg/L were positively associated with GDM, and approximately 23.5% pregnant women had urine MEOHP concentrations greater than 15.6 μg/L. Thus, approximately 23.5% of pregnant women were at the risk of developing GDM due to MEOHP, which suggested that pregnant women should reduce the use of packaged food and cosmetics to reduce the risk of GDM. However, further molecular biology experiments are required to confirm these findings and to elucidate the underlying mechanisms.

Associations of bisphenol exposure with the risk of gestational diabetes mellitus: a nested case-control study in Guangxi, China

A growing number of epidemiologic studies have estimated the associations between endocrine-disrupting chemicals and gestational diabetes mellitus (GDM). However, reports on the association between bisphenol A (BPA) substitutes and GDM are limited. This investigation aimed to explore the associations of maternal serum BPA, bisphenol B (BPB), bisphenol F (BPF), bisphenol S (BPS), and tetrabromobisphenol A (TBBPA) with the risk of GDM. A nested case-control study was performed among 500 pregnant women. In conditional logistic regression models, the OR for BPS was significantly increased in the medium exposure groups (OR = 1.77; 95% CI: 1.01, 3.13) compared with the reference group, while BPA (OR: 0.38, 95%CI: 0.29, 0.50) and TBBPA (OR: 0.67, 95%CI: 0.54, 0.85) were negatively associated with the risk of GDM. In the Bayesian kernel machine regression (BKMR) analysis, the joint effect of bisphenols was positively associated with the risk of GDM. BPS showed positively relationship, while BPA and TBBPA showed negatively relationship, respectively. The quantile g-computation revealed a statistically significant and negative joint effect of the five bisphenols on the risk of GDM (OR: 0.57; 95% CI: 0.46, 0.72) with BPA (70.2%), TBBPA (21.3%), and BPB (8.5%) had positive contribution to the overall effect. These findings suggested that BPS had a positive effect on the risk of GDM, while BPA and TBBPA had negative effect on the risk of GDM. Moreover, exposure to the mixture of the five bisphenols was negatively associated with the risk of GDM.

Serum concentrations of phthalate metabolites in pregnant women and their association with gestational diabetes mellitus and blood glucose levels

Phthalate metabolites are widely present in humans and can have many adverse effects on pregnant women. To date, many studies on the effects of phthalate metabolites on the risk of gestational diabetes mellitus (GDM) have been published, but the findings of these studies are controversial. We conducted a case-control study to quantify the concentrations of seven phthalate metabolites in the serum of pregnant women and to investigate their association with the risk of GDM and blood glucose levels in pregnant women. Therefore, 201 serum samples (139 pregnant women with GDM and 62 control serum samples) were collected from Hangzhou, China, between 2011 and 2012. The results showed that mono butyl phthalate (MBP; mean = 4.08 ng/mL) was the most abundant phthalate metabolites in human serum, followed by mono (2-ethylhexyl) phthalate (MEHP; mean = 1.28 ng/mL) and mono isobutyl phthalate (MiBP; mean = 1.20 ng/mL). The other results indicated significant associations between MBP (β = 2.24, 95 % confidence interval (CI): 1.02, 5.07, P = 0.050) and MiBP (β = 1.84, 95 % CI: 1.03, 3.31, P = 0.041) concentrations in human serum and the incidence of GDM. Moreover, serum MBP (β = 0.40, 95 % CI: 0.10, 0.70, P = 0.010) and MiBP levels (β = 0.18, 95 % CI: 0.010, 0.35, P = 0.047) in humans were positively associated with 2-hour blood glucose levels. Our study provides affirmative evidence on previously inconsistent findings that MBP and MiBP exposure may increase the risk of GDM in pregnant women.

Triclosan in paired-maternal and cord blood, and their relationships with congenital heart disease of baby

Prenatal triclosan (TCS) exposure has been reported to be associated with various birth outcomes and thyroid function, while the study of TCS exposure for congenital heart disease (CHD) patients is limited. In the present study, paired mother-fetus blood samples from CHD and healthy participants were collected to measure TCS exposure levels, and then check their relationship. Coupled with the concentrations of thyroid function biomarkers [free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), and thyroid antibodies (TgAb)] in maternal blood, we aimed to investigate whether the hormone-disrupting properties of TCS will affect its association with CHD. Our results indicated that the maternal TCS concentrations in the CHD group (median 0.31 ng/mL) were significantly lower than those in the control group (0.48 ng/mL, Mann Whitney U test, p = 0.01). Higher interquartile of TCS levels in maternal blood was associated with decrease odds of CHD (adjusted OR = 0.61, 95%CI: 0.41-0.91, p = 0.02). Maternal blood TCS higher than the cut-off value (25th quantile, 0.17 ng/mL) was significantly negatively associated with CHD risk (adjusted OR = 0.24, 95%CI: 0.09-0.62, p < 0.01). Besides, none of the thyroid biomarkers were significantly associated with maternal TCS exposure. However, maternal FT4 concentrations were positively correlated with TCS transplacental transfer rate and cord blood TCS levels (general linear regression, both p < 0.01). The results of molecular docking and dynamics simulation suggested that these correlations might be related to the transthyretin, a thyroid hormone-binding protein involved in the placental thyroid hormone transport system. Overall, our findings indicated that at normal exposure levels, the increase of maternal blood TCS concentration may have an inverse association with CHD, which merits further investigation.

Associations of individual and cumulative urinary phthalate and replacement biomarkers with gestational weight gain through late pregnancy

BACKGROUND/AIMS

Phthalates and their replacements are endocrine/metabolic disruptors that may impact gestational weight gain (GWG) - a pregnancy health indicator. We investigated overall and fetal sex-specific associations of individual and cumulative phthalate/replacement biomarkers with GWG.

METHODS

Illinois women (n = 299) self-reported their weight pre-pregnancy and at their final obstetric appointment before delivery (median 38 weeks). We calculated pre-pregnancy body mass index and gestational age-specific GWG z-scores (GWGz). We quantified 19 phthalate/replacement metabolites (representing 10 parent compounds) in pools of up-to-five first-morning urine samples, collected approximately monthly between 8 and 40 weeks gestation. We used linear regression, quantile-based g-computation (QGComp), and weighted quantile sum regression (WQSR) to evaluate associations of ten biomarkers (individual metabolites or parent molar-sums) individually or as mixtures (in interquartile range intervals) with GWGz. We evaluated associations in all women and stratified by fetal sex.

RESULTS

Individually, sums of metabolites of di(2-ethylhexyl) phthalate (ƩDEHP), di(isononyl) cyclohexane-1,2-dicarboxylate (ƩDiNCH), and di(2-ethylhexyl) terephthalate (ƩDEHTP) had consistent inverse associations with GWGz, and some associations were fetal sex-specific. When evaluating phthalates/replacements as a mixture, QGComp identified ƩDEHP, ƩDEHTP, and mono-(3-carboxypropyl) phthalate, along with sum of di(isononyl) phthalate metabolites (ƩDiNP) and monobenzyl phthalate as notable contributors to lower and higher GWGz, respectively, resulting in a marginal inverse joint association in all women (β: -0.29; 95% CI: -0.70, 0.12). In women carrying females, ƩDEHP contributed to the marginal inverse joint association (β: -0.54; 95% CI: -1.09, 0.03). However, there was no overall association in women carrying males (β: 0.00; 95% CI: -0.60, 0.59), which was explained by approximately equal negative (driven by ƩDEHTP) and positive (driven by ƩDiNP) partial associations. WQSR analyses consistently replicated these QGComp findings.

CONCLUSIONS

Biomarkers of phthalates/replacements were fetal sex-specifically associated with GWGz. Because ƩDEHTP contributed substantively to mixture associations, additional studies in pregnant women may be needed around this plasticizer replacement.

Urinary Phenols in Early to Midpregnancy and Risk of Gestational Diabetes Mellitus: A Longitudinal Study in a Multiracial Cohort

Environmental phenols are ubiquitous endocrine disruptors and putatively diabetogenic. However, data during pregnancy are scant. We investigated the prospective associations between pregnancy phenol concentrations and gestational diabetes mellitus (GDM) risk. In a nested matched case-control study of 111 individuals with GDM and 222 individuals without GDM within the prospective PETALS cohort, urinary bisphenol A (BPA), BPA substitutes (bisphenol F and bisphenol S [BPS]), benzophenone-3, and triclosan were quantified during the first and second trimesters. Cumulative concentrations across the two times were calculated using the area under the curve (AUC). Multivariable conditional logistic regression examined the association of individual phenols with GDM risk. We conducted mixture analysis using Bayesian kernel machine regression. We a priori examined effect modification by Asian/Pacific Islander (A/PI) race/ethnicity resulting from the case-control matching and highest GDM prevalence among A/PIs. Overall, first-trimester urinary BPS was positively associated with increased risk of GDM (adjusted odds ratio comparing highest vs. lowest tertile [aORT3 vs. T1] 2.12 [95% CI 1.00-4.50]). We identified associations among non-A/Ps, who had higher phenol concentrations than A/PIs. Among non-A/PIs, first-trimester BPA, BPS, and triclosan were positively associated with GDM risk (aORT3 vs. T1 2.91 [95% CI 1.05-8.02], 4.60 [1.55-13.70], and 2.88 [1.11-7.45], respectively). Triclosan in the second trimester and AUC were positively associated with GDM risk among non-A/PIs (P < 0.05). In mixture analysis, triclosan was significantly associated with GDM risk. Urinary BPS among all and BPA, BPS, and triclosan among non-A/PIs were associated with GDM risk. Pregnant individuals should be aware of these phenols' potential adverse health effects.

Assessing urinary phenol and paraben mixtures in pregnant women with and without gestational diabetes mellitus: A case-control study

Prior studies have identified the associations between environmental phenol and paraben exposures and increased risk of gestational diabetes mellitus (GDM), but no study addressed these exposures as mixtures. As methods have emerged to better assess exposures to multiple chemicals, our study aimed to apply Bayesian kernel machine regression (BKMR) to evaluate the association between phenol and paraben mixtures and GDM. This study included 64 GDM cases and 237 obstetric patient controls from the University of Oklahoma Medical Center. Mid-pregnancy spot urine samples were collected to quantify concentrations of bisphenol A (BPA), benzophenone-3, triclosan, 2,4-dichlorophenol, 2,5-dichlorophenol, butylparaben, methylparaben, and propylparaben. Multivariable logistic regression was used to evaluate the associations between individual chemical biomarkers and GDM while controlling for confounding. We used probit implementation of BKMR with hierarchical variable selection to estimate the mean difference in GDM probability for each component of the phenol and paraben mixtures while controlling for the correlation among the chemical biomarkers. When analyzing individual chemicals using logistic regression, benzophenone-3 was positively associated with GDM [adjusted odds ratio (aOR) per interquartile range (IQR) = 1.54, 95% confidence interval (CI) 1.15, 2.08], while BPA was negatively associated with GDM (aOR 0.61, 95% CI 0.37, 0.99). In probit-BKMR analysis, an increase in z-score transformed log urinary concentrations of benzophenone-3 from the 10th to 90th percentile was associated with an increase in the estimated difference in the probability of GDM (0.67, 95% Credible Interval 0.04, 1.30), holding other chemicals fixed at their medians. No associations were identified between other chemical biomarkers and GDM in the BKMR analyses. We observed that the association of BPA and GDM was attenuated when accounting for correlated phenols and parabens, suggesting the importance of addressing chemical mixtures in perinatal environmental exposure studies. Additional prospective investigations will increase the understanding of the relationship between benzophenone-3 exposure and GDM development.

The association of serum phthalate metabolites with biomarkers of ovarian reserve in women of childbearing age

Phthalates (PAEs) are widely used plasticizers drawing increasing concern due to reproductive toxicity. However, studies on serum PAEs metabolites (mPAEs) and their associations with human ovarian function remain very scarce. In this study, from April 2019 to August 2020, a total of 297 women of childbearing age were recruited in Tianjin, China. Eleven mPAEs were analyzed in serum samples and eight mPAEs were detected at frequencies > 65% with median concentrations of 0.43-15.3 ng/mL. In multinomial logistic analysis, an increase in serum mono (2-isobutyl) phthalate (miBP) was associated with decline in antral follicle count (AFC) (OR=1.26, 95% CI: 0.99, 1.61) and 5-mono-(2-ethyl-5-hydroxyhexyl) phthalate (mEHHP) was significantly associated with AFC increase (OR=1.43, 95% CI: 1.06, 1.92), which were aligned with the associations found between mPAEs and AMH through generalized linear regression. In multiple linear regression models, per 10% increase in serum mono (2-ethylhexyl) phthalate (mEHP), mono (2-ethyl-5-oxohexyl) phthalate (mEOHP) (oxo-mEHP), and principal component 1 featured for high concentrations of mono-n-butyl phthalate (mBP), miBP and mEHP were associated with 0.15 (95% CI: -0.29, -0.02), 0.01 (95% CI: -0.01, 0.00) and 0.01 (95% CI: -0.02, 0.00) ln-unit decrease in estradiol (E2) levels, respectively, while mono-[(2-carboxymethyl) hexyl] phthalate (mCMHP) (carboxymethyl-mEHP) was positively associated with 0.05 ln-unit increase of E2 (95% CI: 0.02, 0.08). The observed negative associations between mPAEs and the Anti-Müllerian hormone (AMH) also aligned with the change in AFC. Generalized linear regression also revealed nonlinear associations between mono-ethyl phthalate (mEP), mCMHP and follicle-stimulating hormone (FSH). Overall, serum mEHP and its metabolites were negatively associated with E2. miBP was negatively associated with AFC. The nonlinear associations between mPAEs and FSH, and AMH need further study.

Environmental health influences in pregnancy and risk of gestational diabetes mellitus: a systematic review

Background

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications globally. Environmental risk factors may lead to increased glucose levels and GDM, which in turn may affect not only the health of the mother but assuming hypotheses of "fetal programming", also the health of the offspring. In addition to traditional GDM risk factors, the evidence is growing that environmental influences might affect the development of GDM. We conducted a systematic review analyzing the association between several environmental health risk factors in pregnancy, including climate factors, chemicals and metals, and GDM.

Methods

We performed a systematic literature search in Medline (PubMed), EMBASE, CINAHL, Cochrane Library and Web of Science Core Collection databases for research articles published until March 2021. Epidemiological human and animal model studies that examined GDM as an outcome and / or glycemic outcomes and at least one environmental risk factor for GDM were included.

Results

Of n = 91 studies, we classified n = 28 air pollution, n = 18 persistent organic pollutants (POP), n = 11 arsenic, n = 9 phthalate n = 8 bisphenol A (BPA), n = 8 seasonality, n = 6 cadmium and n = 5 ambient temperature studies. In total, we identified two animal model studies. Whilst we found clear evidence for an association between GDM and air pollution, ambient temperature, season, cadmium, arsenic, POPs and phthalates, the findings regarding phenols were rather inconsistent. There were clear associations between adverse glycemic outcomes and air pollution, ambient temperature, season, POPs, phenols, and phthalates. Findings regarding cadmium and arsenic were heterogeneous (n = 2 publications in each case).

Conclusions

Environmental risk factors are important to consider in the management and prevention of GDM. In view of mechanisms of fetal programming, the environmental risk factors investigated may impair the health of mother and offspring in the short and long term. Further research is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13965-5.

Associating diethylhexyl phthalate to gestational diabetes mellitus via adverse outcome pathways using a network-based approach

Gestational diabetes mellitus (GDM) is a common pregnancy complication that is harmful to both the woman and fetus. Several epidemiological studies have found that exposure to diethylhexyl phthalate (DEHP), an endocrine disruptor ubiquitous in the environment, may be associated with GDM. This study aims to investigate the mechanism between DEHP and GDM using the adverse outcome pathway (AOP) framework, which can integrate information from different sources to elucidate the causal pathways between chemicals and adverse outcomes. We applied a network-based workflow to integrate diverse information to generate computational AOPs and accelerate the AOP development. The interactions among DEHP, genes, phenotypes, and GDM were retrieved from several publicly available databases, including the Comparative Toxicogenomics Database (CTD), Computational Toxicology (CompTox) Chemicals Dashboard, DisGeNET, MalaCards, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG). Based on the above interactions, a DEHP-Gene-Phenotype-GDM network consisting of 52 nodes and 227 edges was formed to support AOP construction. The filtered genes and phenotypes were assembled as molecular initiating events (MIEs) and key events (KEs) according to the upstream and downstream relationships, generating a computational AOP (cAOP) network. Based on the Organization for Economic Co-operation and Development handbook of AOPs, a cAOP was assessed and applied to determine the effects of DEHP on GDM. DEHP could increase TNF-α, downregulate the glucose uptake process, and lead to GDM. Overall, this study revealed the utility of computational methods in integrating a variety of datasets, supporting AOP development, and facilitating a better understanding of the underlying mechanism of exposure to chemicals on human health.

Phthalate metabolites in paired human serum and whole blood

Presence of phthalate metabolites (PMs) in human serum has been well documented. However, the distribution pattern of PMs in different human blood matrixes remains not well known. To investigate this, paired serum and whole blood samples were collected from 145 adults (76 males and 69 females) in Quzhou, China, and analyzed for nine PMs in this study. All PMs had high detection frequencies (> 70%) in human serum and whole blood, except mono benzyl phthalate. Total concentrations of detected PMs in serum and whole blood were 0.70-61 ng/mL (mean 12 ng/mL) and 1.6-33 ng/mL (7.5 ng/mL), respectively. Mono methyl phthalate (MMP), mono (2-ethylhexyl) phthalate, and mono butyl phthalate were consistently the predominant PMs in human serum and whole blood, with the mean concentrations of 3.4 and 2.0 ng/mL, 3.3 and 2.1 ng/mL, and 2.8 and 1.8 ng/mL, respectively. Females had higher mean serum concentrations of PMs, except MBP, than males. Youngest age group (20-30 years) consistently had the lowest mean whole blood levels of all PMs. For the first time, the distribution pattern of PMs in human blood was evaluated based on the calculated partitioning coefficient (K_p) between serum and whole blood. MMP had the highest mean K_p value (1.6; 10th-90th percentile: 1.0-2.2), while mono (2-ethyl-5-oxohexyl) phthalate had the lowest mean K_p value (0.63; 10th-90th percentile: 0.25-1.3). These results help better understand the occurrence of PMs in human blood.

Protective effect of nimbolide against streptozotocin induced gestational diabetes mellitus in rats via alteration of inflammatory reaction, oxidative stress, and gut microbiota

BACKGROUND

Gestational diabetes mellitus (GDM) is a significant pregnancy-related condition, which showed effect on the development of fetal. Anti-inflammatory and antioxidant therapy commonly used for the treatment of GDM. Nimbolide already confirmed their anti-inflammatory and anti-oxidant effect against various animal disease model. Our objective in this research is to investigate the protective effect of nimbolide against STZ induced GDM and elucidate the mechanism.

METHODS

In this experimental study, pregnant female Wistar rats were used and STZ (40 mg/kg) was used to induce the GDM. Blood glucose level (BGL), body weight and plasma insulin were assessed at regular time (gestational day 0, 9, and 18). Water intake, food intake, fecal and urine output were also estimated. In the female rats, hemoglobin (Hb), glycalated hemoglobin (HbA1c), hepatic glycogen, fructosamine, adiponectin, leptin, lipid, antioxidant and inflammatory cytokines parameters were estimated. In the fetuses, the fetues weight, implementation loss, and fetal weight were estimated. At the completion of the protocol, biochemical parameters were calculated. Gut microbiota was estimated in end of the study.

RESULTS

Nimbolide treatment significantly (p < .001) improved the fetuses level and suppressed the fetal weight and implantation loss. Nimbolide treatment significantly (p < .001) suppressed the BGL and enhanced the body weight, insulin level. Nimbolide treatment suppressed the water intake, food intake, urinary and fecal output. Nimbolide significantly (p < .001) suppressed the fructosamine, leptin and enhanced the adiponectin level. Nimbolide treatment significantly (p < .001) decreased the malonaldehyde (MDA) level and boosted the total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and catalase (CAT); suppressed the level of TNF-α, IL-1β, IL-6, and boosted the level of IL-10. Furthermore, nimbolide treatment reversed the gut microbiota alteration induced via STZ in female rats. At the phylum level, the Firmicutes and Bacteroidetes relative abundance was altered via nimbolide treatment. The ratio of F/B boosted in GDM group and nimbolide treatment significantly (p < .001) suppressed. Nimbolide considerably suppressed the firmicutes and enhanced the Bacteroidetes, CAG-352, Lacnospirace.

CONCLUSION

Based on the findings, we may conclude that nimbolide protects the pregnant rats from GDM via alteration of inflammation, oxidative stress, and gut microbiota.

Endocrine-disrupting chemicals and the risk of gestational diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

To conduct a comprehensive systematic review and meta-analysis to estimate the relationship between endocrine-disrupting chemicals (EDCs), including polychlorinated biphenyls (PCBs), poly-brominated diphenyl ethers (PBDEs), phthalates (PAEs), and per- and polyfluoroalkyl substances (PFAS) exposure and risk of gestational diabetes mellitus (GDM).

METHODS

Relevant studies from their inception to November 2021 were identified by searching EMBASE, PubMed, and Web of Science. The cohort and case-control studies that reported effect size with 95% confidence intervals (CIs) of EDC exposure and GDM were selected. The heterogeneity among the included studies was quantified by I² statistic. Publication bias was evaluated through the Begg and Egger tests.

RESULTS

Twenty-five articles with a total of 23,796 participants were found. Results indicated that exposure to PCBs has a significant influence on the incidence of GDM (OR = 1.14; 95% CI = 1.00--1.31; n = 8). The risk of GDM was found to be associated with PBDE exposure (OR = 1.32; 95% CI = 1.15-1.53; n = 4). PAEs and PFASs exposure were also positively associated with the risk of GDM, with summary ORs of 1.10 (95% CI = 1.03-1.16; n = 7 for PAEs) and 1.09 (95% CI = 1.02-1.16; n = 11 for PFASs), respectively. When only cohort studies were considered, the summary OR between PCBs exposure and the risk of GDM was 0.99 (95% CI = 0.91-1.09; n = 5). Meanwhile, the summary ORs from cohort studies for PBDEs, PAEs, and PFASs exposure were 1.12 (95% CI = 1.00-1.26; n = 2), 1.08 (95% CI = 1.02-1.15; n = 5), and 1.06 (95% CI = 1.00-1.12; n = 8), respectively. The Beggs and Egger tests did not show publication bias, and the sensitivity analyses did not change the results in this meta-analysis.

CONCLUSION

These results support that exposure to certain EDCs, including PCBs, PBDEs, PAEs, and PFAS, increase the risk of GDM. Further large-sample epidemiologic researches and mechanistic studies are needed to verify the potential relationship and biological mechanisms. These results are of public health significance because the daily EDC exposure is expected to increase the risk of GDM development.

The Presence of Triclosan in Human Hair Samples in Poland-A Pilot Study

Triclosan (TCS) is an organic substance showing antibacterial action, which is commonly used in many branches of industry, including, among others, cosmetics, pharmaceuticals and the food industry. TCS may penetrate into living organisms and negatively affect the health of humans and animals. The majority of previous investigations on TCS biomonitoring in humans have been performed on urine, but currently, studies on hair samples are becoming increasingly important. The aim of this study was to evaluate TCS concentration levels in residents of Olsztyn, a city in northeastern Poland, using a liquid chromatography-mass spectrometry technique. The presence of TCS was observed in 96.7% of samples tested, with concentration levels from 37.9 pg/mg to 3386.5 pg/mg. The mean concentration level of TCS in the present study was 402.6 (±803.6) pg/mg, and the median value was 103.3 pg/mg. Although there were some differences in TCS concentration levels between males and females, humans of various ages and humans with colored and natural hair had no statistically significant differences in TCS concentration levels. The obtained results have clearly indicated that people living in northeastern Poland are exposed to TCS to a large degree, and hair analysis, despite some limitations, is a suitable method for TCS biomonitoring in humans.

Prenatal phthalate exposure in relation to placental corticotropin releasing hormone (pCRH) in the CANDLE cohort

CONTEXT

Phthalates may disrupt maternal-fetal-placental endocrine pathways, affecting pregnancy outcomes and child development. Placental corticotropin releasing hormone (pCRH) is critical for healthy pregnancy and child development, but understudied as a target of endocrine disruption.

OBJECTIVE

To examine phthalate metabolite concentrations (as mixtures and individually) in relation to pCRH.

DESIGN

Secondary data analysis from a prospective cohort study.

SETTING

Prenatal clinics in Tennessee, USA.

PATIENTS

1018 pregnant women (61.4% non-Hispanic Black, 32% non-Hispanic White, 6.6% other) participated in the CANDLE study and provided data. Inclusion criteria included: low-medical-risk singleton pregnancy, age 16-40, and gestational weeks 16-29.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Plasma pCRH at two visits (mean gestational ages 23.0 and 31.8 weeks) and change in pCRH between visits (ΔpCRH).

RESULTS

In weighted quantile sums (WQS) regression models, phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.07, 95 %CI: 0.02, 0.11) but lower pCRH at Visit 2 (β = -0.08, 95 %CI: -0.14, -0.02). In stratified analyses, among women with gestational diabetes (n = 59), phthalate mixtures were associated with lower pCRH at Visit 1 (β = -0.17, 95 %CI: -0.35, 0.0006) and Visit 2 (β = -0.35, 95 %CI: -0.50, -0.19), as well as greater ΔpCRH (β = 0.16, 95 %CI: 0.07, 0.25). Among women with gestational hypertension (n = 102), phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.20, 95 %CI: 0.03, 0.36) and Visit 2 (β = 0.42; 95 %CI: 0.19, 0.64) and lower ΔpCRH (β = -0.17, 95 %CI: -0.29, -0.06). Significant interactions between individual phthalate metabolites and pregnancy complications were observed.

CONCLUSIONS

Phthalates may impact placental CRH secretion, with differing effects across pregnancy. Differences in results between women with and without gestational diabetes and gestational hypertension suggest a need for further research examining whether women with pregnancy complications may be more vulnerable to endocrine-disrupting effects of phthalates.

Association Between Phthalate Exposure in Pregnancy and Gestational Diabetes: A Chinese Cross-Sectional Study

Objective

The present study aims to explore the association between phthalate exposure and the risk of gestational diabetes mellitus (GDM).

Materials and Methods

A total of 11 plasticizer metabolites were measured in patient morning urine using high-performance liquid chromatography. Furthermore, fasting blood glucose and fasting insulin were detected in first-trimester blood samples. The chemical concentration was described using the median, the metabolite concentration difference between the GDM and control groups was compared using the bootstrap method, and the correlations of the fasting blood glucose, fasting insulin, insulin resistance index, and phthalic acid ester (PAE) metabolites were analyzed using Spearman correlation analysis. The multivariate logistic regression model and predictive probability map were performed to help assess the linearity and nature of any dose–response relationship.

Results

Of the 224 women recruited for the present study, 200 met the inclusion criteria. Their measured outcomes and biomonitoring data were examined for the presence of chemicals. The results showed that the patients in the GDM group had higher mono-(2-ethylhexyl) phthalate (MEHP) and methylerythritol cyclophosphane concentrations in their bodies than the patients in the control group. Statistically significant MEHP–GDM associations were also observed (P < 0.001). The GDM and MEHP dose–response relationships were different among pregnant women aged <35 years and those aged >35 years (P < 0.001). Furthermore, gestational age >28 weeks exhibited similar changes to those aged ≤28 weeks (P = 0.059).

Conclusion

The findings of the present study add to the growing body of evidence supporting phthalate exposure as a GDM risk factor.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

Exposure to endocrine disrupting chemicals (EDCs) and cardiometabolic indices during pregnancy: The HOME Study

BACKGROUND

Toxicology studies have identified pregnancy as a window of susceptibility for endocrine disrupting chemicals (EDCs) and cardiometabolic indices in women. No study in humans, however, has examined EDC mixtures and cardiometabolic indices during pregnancy.

METHODS

We used the Health Outcomes and Measures of the Environment (HOME) Study to examine whether bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFAS), and phthalates are associated with blood pressure, glucose, and lipids in 388 pregnant women. We measured PBDEs and PFAS in serum at 16 weeks gestation, while BPA and phthalate metabolites were quantified in urine at 16 and 26 weeks gestation. We used linear regression and Bayesian Kernel Machine Regression (BKMR) to estimate covariate-adjusted associations of individual EDCs and their mixtures with cardiometabolic indices during pregnancy.

RESULTS

A 10-fold increase in BDE-28 was associated with a 13.1 mg/dL increase in glucose (95% Confidence Interval [CI] 2.9, 23.2) in linear regression. The BKMR model also identified BDE-28 as having a positive association with glucose. BDE-28, BDE-47, and BDE-99 were positively associated with total cholesterol in both single- and multi-pollutant models, whereas a suggestive negative association was noted with BDE-153. Mono-n-butyl phthalate (MBP) (β = -7.9 mg/dL, 95% CI -12.9, -3.0) and monobenzyl phthalate (MBzP) (β = -6.3 mg/dL, 95% CI -10.6, -2.0) were both associated with significant decreases in cholesterol in linear regression, but only MBzP was identified as an important contributor in the BKMR model.

CONCLUSION

Overall, we observed positive associations between PBDEs with glucose and cholesterol levels during pregnancy, while negative associations were found between some phthalate biomarkers and cholesterol. No relationship was noted for BPA or PFAS with cardiometabolic indices during pregnancy across both models.

Bisphenol A exposure and abnormal glucose tolerance during pregnancy: systematic review and meta-analysis

In the present work, a systematic review and meta-analysis were performed to examine the probable relation between maternal exposure to bisphenol A (BPA), as estrogen-disrupting compounds, and gestational diabetes mellitus (GDM), and impaired glucose tolerance (IGT). We comprehensively searched three electronic databases to retrieve published studies on maternal exposure to BPA and GDM/IGT, through February 2021. Cochran's Q test and I2 statistics were employed for testing heterogeneity across studies. DerSimonian and Liard random-effects model was used to determine the pooled estimates. Otherwise, the fixed-effects model with inverse-variance weights was applied. Sensitivity analysis was performed to determine the robustness of the results by excluding each study from the pooled estimate. The potential publication bias was examined using Begg's and Egger's tests. The pooled odds ratio did not show BPA exposure to be a significant risk factor for GDM (OR = 0.90, 95% CI = 0.62-1.33, I2: 50.7%). Also, no significant association was observed between BPA exposure and risk of IGT (OR = 0.93, 95% CI = 0.40-2.18, I2: 11.5%). Based on the findings of this study, no association was found between exposure to BPA during pregnancy and the risk of GDM/IGT. Albeit no heterogeneity was found between studies.

Association of endocrine disrupting chemicals levels in serum, environmental risk factors, and hepatic function among 5- to 14-year-old children

Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during childhood, however, the association among the exposure level of EDCs such as Nonylphenol (NP), Bisphenol A (BPA), Dimethyl phthalate (DMP) in children and environmental risk factors, as well as hepatic function has not been elaborated. This study aimed to discuss this interesting relationship among NP, BPA, DMP concentrations in serum, environmental risk factors, hepatic function of 5- to 14-year-old children in industrial zone, residential zone and suburb in northern district of Guizhou Province, China. In Zunyi city, 1006 children participated in cross-sectional health assessments from July to August 2018, and their parents completed identical questionnaires on the environmental risk factors of EDCs exposure to mothers and children. Serum NP, BPA and DMP concentrations were measured by high performance liquid chromatography (HPLC). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ALT, total bilirubin (TBIL), direct bilirubin (DBIL) and indirect bilirubin (IBIL) were detected with automatic biochemical analyzer. The median concentrations of serum NP, BPA, and DMP in the participants were 45.85 ng/mL, 26.31 ng/mL and 31.62 ng/mL, respectively, which were higher than the environmental concentration limits of the U.S. National Environmental Protection Agency (EPA). Hair gels used during pregnancy, types of domestic drinking water, nail polish and cosmetics used by children were significantly positive correlated with serum NP concentration (P < 0.05). Gender, feeding pattern, plastic water cup used during pregnancy, hair spray and perfume use for children, duration of children birth, materials for baby bottle or cup and ways to plastic products were significantly positively correlated with serum BPA concentration (P < 0.05). Gender, perms used during pregnancy, hair spray and perfume use for children, using plastic lunch box during pregnancy, duration of children birth, exposure to pesticides, parents' occupations were significantly positively correlated with serum DMP concentrations (P < 0.05). Serum NP (β = 0.296, P = 0.036) and DMP (β = 0.316, P = 0.026) concentrations and TBIL level were significantly positively correlated. Serum NP concentration and the levels of IBIL (β = 0.382, P = 0.006) are significantly positively correlated. Cosmetics used during pregnancy significantly increased AST level (β = 2.641, P = 0.021). There was a positive correlation between the frequency of hair spray and perfume use for children and the AST (β = 4.241, P = 0.022). NP, BPA and DMP, which were commonly detected in the serum of children aged 5-14 years old in Zunyi City, Northern Guizhou Province, China, were closely related to the environmental risk factors of exposure environment during pregnancy, infancy and school age. Exposure to NP, BPA and DMP would have negative effects on hepatic function, and these effects showed differences in gender and geographical location. Notably,The relationships were more evident in girls than in boys.

REPRODUCTIVE TOXICOLOGY: Pregnancy exposure to endocrine disrupting chemicals: implications for women's health

Women are ubiquitously exposed to non-persistent endocrine disrupting chemicals (EDCs) from food contact materials and personal care products. Understanding the impacts of exposure to these chemicals on pregnancy and long-term health outcomes in women is a critical area of research that has been largely overlooked. This brief review focuses on the epidemiologic literature exploring associations of non-persistent EDCs - including phthalates, parabens, bisphenols, and triclosan - with maternal pregnancy outcomes and long-term health outcomes in women. We focus on the challenges of this research, particularly assessing non-persistent EDC exposures, aspects of study design, and statistical approaches. We conclude by reviewing the best practices for non-persistent EDC research with regards to pregnancy and women's health. Though limited, we found some evidence indicating that exposure to non-persistent EDCs is associated with pregnancy health. However, findings from these studies have been inconsistent and require corroboration. Recent studies have also proposed that non-persistent EDC exposures in pregnancy may adversely affect postnatal maternal health. To date, only a few studies have been conducted and have only focused on postpartum weight. More research is needed in this area to inform efforts to promote optimal health across the lifespan of women.

Effects of single and combined gestational phthalate exposure on blood pressure, blood glucose and gestational weight gain: A longitudinal analysis

Few studies have investigated the association of gestational exposure to phthalate with metabolic risk and have reached inconsistent conclusions. Based on the Ma'anshan Birth Cohort, 3273 women were included in the present study. All participants provided up to three urine samples for 7 phthalate metabolite measurements. The hazard index (HI) was used to evaluate the cumulative risk of multiple phthalate coexposures. The outcomes of interest included hypertensive disorders of pregnancy (HDOP), gestational diabetes mellitus (GDM), and gestational weight gain (GWG). The incidences of HDOP, GDM, and excessive GWG were 5.93%, 13.09%, and 28.95%, respectively. Exposure to a single phthalate metabolite or a specific diester during the first trimester of pregnancy elevated blood pressure (BP) and fasting plasma glucose (FPG) in the third trimester and body weight gain throughout pregnancy. However, inverse relationships were revealed for some phthalate metabolites, which were inconsistent with the results of their diesters. The HI value during the first trimester was positively associated with subsequent BP, FPG, and GWG. In addition, HI during the first trimester increased the risks of GDM [odds ratio (OR) = 1.34, 95% confidence intervals (CIs) = 1.02-1.75)] and excessive GWG (OR = 1.76, 95% CIs = 1.41-2.19) in a linear manner thereafter. Notably, phthalates might directly increase maternal blood glucose and pressure, and these changes were secondary effects of the obesiogenic effects of certain phthalates. In conclusion, exposure to single and multiple phthalates during the first trimester of pregnancy increased the risks of maternal metabolic syndrome components. However, the conflicting findings between phthalates and their metabolites need to be interpreted carefully.

NF-κB-An Important Player in Xenoestrogen Signaling in Immune Cells

The proper functioning of the immune system is critical for an effective defense against pathogenic factors such as bacteria and viruses. All the cellular processes taking place in an organism are strictly regulated by an intracellular network of signaling pathways. In the case of immune cells, the NF-κB pathway is considered the key signaling pathway as it regulates the expression of more than 200 genes. The transcription factor NF-κB is sensitive to exogenous factors, such as xenoestrogens (XEs), which are compounds mimicking the action of endogenous estrogens and are widely distributed in the environment. Moreover, XE-induced modulation of signaling pathways may be crucial for the proper development of the immune system. In this review, we summarize the effects of XEs on the NF-κB signaling pathway. Based on our analysis, we constructed a model of XE-induced signaling in immune cells and found that in most cases XEs activate NF-κB. Our analysis indicated that the indirect impact of XEs on NF-κB in immune cells is related to the modulation of estrogen signaling and other pathways such as MAPK and JAK/STAT. We also summarize the role of these aspects of signaling in the development and further functioning of the immune system in this paper.

Pre-Gestational Consumption of Ultra-Processed Foods and Risk of Gestational Diabetes in a Mediterranean Cohort. The SUN Project

We aimed to investigate the relationship between the pre-gestational consumption of ultra-processed foods (UPF) and the risk of gestational diabetes (GDM). We carried out a prospective study among 3730 Spanish women of the SUN cohort who reported at least one pregnancy after baseline recruitment. Cases of GDM were identified among women with a confirmed diagnosis of GDM. UPF consumption was assessed through a validated, semi-quantitative food frequency questionnaire and the frequency of UPF consumption was categorized in tertiles. We identified 186 cases of GDM. In the pooled sample, we did not observe a significant association of UPF with the risk of GDM. When we stratified by age, the multivariate OR for the third tertile of UPF consumption compared with the lowest one was 2.05 (95% CI 1.03, 4.07) in women aged ≥30 years at baseline (P_trend = 0.041). The association remained significant in a sensitivity analysis after changing many of our assumptions and adjusting for additional confounders. No association between a higher UPF consumption and GDM risk was observed in women aged 18–29 years. The pre-gestational UPF consumption may be a risk factor for GDM, especially in women aged 30 years or more. Confirmatory studies are needed to validate these findings.

Inverse association of certain seminal phthalate metabolites with semen quality may be mediated by androgen synthesis: A cross-sectional study from the South China

BACKGROUND

Several in vitro and in vivo studies have demonstrated the effects of phthalates on androgen synthesis, and the adverse outcomes of phthalate exposure on male reproductive function have been reported. However, the direct relationship among these three factors remains unknown.

OBJECTIVE

To explore the potential roles of steroids involved in androgen synthesis in the association between phthalate exposure and semen quality.

METHODS

Eighteen phthalate metabolites (mPAEs) and nine steroids were analyzed in semen samples of 403 male participants aged 18-54 years from a hospital in Shenzhen, China. The associations across phthalate metabolites, steroids, and eleven semen quality parameters were evaluated by multivariate linear regression and logistical regression models. The potential contributions of steroids to the associations between phthalate metabolites and semen quality outcomes were explored by mediation effect analysis.

RESULTS

In this cross-sectional study, mono-n-butyl phthalate (MnBP) was inversely associated with nine continuous semen quality parameters in a dose-dependent manner (all p for trend < 0.05). Positive associations were observed between MnBP tertiles and androstenedione (ADD) and pregnenolone (PGL), of which only ADD was significantly associated with sperm quality (i.e., motility, p < 0.05). The estimated average mediated effects of seminal ADD on the associations between MnBP and lower sperm motility parameters (i.e., total motility, TR; progressive motility, PR; curvi-linear velocity, VCL) were 6.4-11.9% (all p < 0.05). The potential mediated effects of ADD on the increasing risks of TR (9.8%) and PR (8.5%) abnormalities induced by MnBP exposure were also observed in logistical regression analysis.

CONCLUSION

Our results indicated that androgen synthesis in reproductive system may be potentially affected by phthalate exposure, thereby resulting in reduced sperm motility in adult men. Further studies are needed to understand the actual roles and underlying mechanism of action of androstenedione on these associations.

Praegnatio Perturbatio-Impact of Endocrine-Disrupting Chemicals

The burden of adverse pregnancy outcomes such as preterm birth and low birth weight is considerable across the world. Several risk factors for adverse pregnancy outcomes have been identified. One risk factor for adverse pregnancy outcomes receiving considerable attention in recent years is gestational exposure to endocrine-disrupting chemicals (EDCs). Humans are exposed to a multitude of environmental chemicals with known endocrine-disrupting properties, and evidence suggests exposure to these EDCs have the potential to disrupt the maternal-fetal environment culminating in adverse pregnancy and birth outcomes. This review addresses the impact of maternal and fetal exposure to environmental EDCs of natural and man-made chemicals in disrupting the maternal-fetal milieu in human leading to adverse pregnancy and birth outcomes-a risk factor for adult-onset noncommunicable diseases, the role lifestyle and environmental factors play in mitigating or amplifying the effects of EDCs, the underlying mechanisms and mediators involved, and the research directions on which to focus future investigations to help alleviate the adverse effects of EDC exposure.

Impact of gestational exposure to endocrine disrupting chemicals on pregnancy and birth outcomes

With the advent of industrialization, humans are exposed to a wide range of environmental chemicals, many with endocrine disrupting potential. As successful maintenance of pregnancy and fetal development are under tight hormonal control, the gestational exposure to environmental endocrine disrupting chemicals (EDC) have the potential to adversely affect the maternal milieu and support to the fetus, fetal developmental trajectory and birth outcomes. This chapter summarizes the impact of exposure to EDCs both individually and as mixtures during pregnancy, the immediate and long-term consequences of such exposures on the mother and fetus, the direct and indirect mechanisms through which they elicit their effects, factors that modify their action, and the research directions to focus future investigations.

Association between prenatal phthalate exposure and gestational metabolic syndrome parameters: a systematic review of epidemiological studies

The relationship of intrauterine phthalate exposure with gestational metabolic syndrome (GMS) parameters is inconsistently reported. We performed a systematic review to evaluate the association between prenatal phthalate exposure and GMS parameters. A literature search was performed in three databases. According to the defined PECOS statement, eligible studies were identified. The method and result for each study was qualitatively summarized with great emphasis on study design and exposure assessment. Fourteen studies were included in the present systematic review. Two studies used one-spot serum sample for evaluation of phthalate exposure, while others used 1-4 urine samples. Concentrations of phthalate metabolites varied substantially, and the levels in serum were greatly lower than those in urine. These studies observed no interstudy or intrastudy consistency for association between phthalates and GMS in pregnant women cross-sectionally or longitudinally, regardless of phthalates species or GMS indicator. Most reported associations were not significantly different from null result. Besides, positive and negative relationships also existed. The current epidemiological data do not support the hypothesis that prenatal exposure to phthalates increases GMS risk.

Prenatal exposure to phthalates and maternal metabolic outcomes in a high-risk pregnant Latina population

BACKGROUND

Phthalates are a group of endocrine disrupting chemicals that are heavily used throughout industry in flexible plastic and personal-care products. As a result, detectable levels of their metabolites are readily found in humans. Some studies have shown associations of phthalates with diabetes, but associations with gestational diabetes mellitus (GDM) are less clear.

OBJECTIVE

To investigate the association of 11 prenatal urinary phthalate metabolites and development of GDM, impaired glucose tolerance (IGT), continuous plasma glucose level, and excessive gestational weight gain (GWG) in a population of pregnant Latina women (N = 415) enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study.

METHODS

Phthalate metabolite levels were measured via mass spectrometry from two urine samples collected in the end of the first and second trimester. Maternal plasma glucose levels, prior diabetes diagnosis, GDM diagnosis, and weight gain were abstracted from medical records. Multiple regression was used to evaluate the association between the average of the two urinary phthalate metabolites levels and maternal metabolic outcomes. In our sensitivity analysis, phthalate levels were categorized by level (as quartiles of exposure) and by timing of urine sample collection (as taken in first and second half of pregnancy).

RESULTS

Consistent with findings from a nationally representative sample, all of the individual phthalate metabolites were detected in majority of mothers. Thirty-one mothers (7.5%) were diagnosed with GDM, 49 mothers (14.7%) displayed IGT, and 223 mothers (55.1%) gained an excessive amount of weight during their pregnancy. MEP concentrations were associated with an increased odds of excessive GWG (OR: 1.1, 95% CI: 1.0 to 1.3). We did not find an association between any phthalate metabolite and any maternal glucose outcome.

CONCLUSION

Contrary to previous studies, our findings do not support an association of prenatal phthalate levels and increased odds for hyperglycemia, IGT, or GDM. But, we did find an increased odds of excessive GWG, a well-known risk factor for GDM.

Serum Bisphenol A, glucose homeostasis, and gestational diabetes mellitus in Chinese pregnant women: a prospective study

Lab studies have suggested that exposure to Bisphenol A (BPA) could disturb glucose homeostasis, but epidemiologic studies are limited and show inconsistent results for pregnant women. For this, 535 pregnant women were selected from a pregnant women cohort established in Tangshan City in North China between 2013 and 2014. Serum concentrations of BPA were measured in the early term of pregnancy, and fasting glucose and insulin levels were repeatedly measured in each of three terms of pregnancy (early, middle, and late). Gestational diabetes mellitus (GDM) were examined by Oral Glucose Tolerance Test (OGTT) in the middle and late terms of pregnancy. BPA was detected in 97.5% of pregnant women with a median of 6.50 ng/ml. Natural log-transformed BPA (Ln BPA) was positively associated with fasting glucose level (β (95% CI): 0.038 (0.015~0.061)), fasting insulin level (0.195 (0.069~0.321)), and homeostasis model insulin resistance index (HOMA-IR) (0.226 (0.087~0.364)) in the middle term of pregnancy by multiple linear regression model after adjusting for potential confounders. After serum BPA levels were divided into three groups (low, middle, and high), BPA showed a positive dose-response relationship with blood glucose, insulin, and HOMA-IR in the middle term of pregnancy. Increased BPA concentration tended to increase the RR of GDM although not statistically significant (risk ratio: 2.51 (95% CI: 0.68~9.30) for high vs low tertile of BPA concentrations). These findings suggested that exposure to BPA might affect glucose homeostasis and the middle term of pregnancy was a potentially sensitive period.

Environmental Endocrine-Disrupting Chemical Exposure: Role in Non-Communicable Diseases

The exponential growth of pollutant discharges into the environment due to increasing industrial and agricultural activities is a rising threat for human health and a biggest concern for environmental health globally. Several synthetic chemicals, categorized as potential environmental endocrine-disrupting chemicals (EDCs), are evident to affect the health of not only livestock and wildlife but also humankind. In recent years, human exposure to environmental EDCs has received increased awareness due to their association with altered human health as documented by several epidemiological and experimental studies. EDCs are associated with deleterious effects on male and female reproductive health; causes diabetes, obesity, metabolic disorders, thyroid homeostasis and increase the risk of hormone-sensitive cancers. Sewage effluents are a major source of several EDCs, which eventually reach large water bodies and potentially contaminate the drinking water supply. Similarly, water storage material such as different types of plastics also leaches out EDCs in drinking Water. Domestic wastewater containing pharmaceutical ingredients, metals, pesticides and personal care product additives also influences endocrine activity. These EDCs act via various receptors through a variety of known and unknown mechanisms including epigenetic modification. They differ from classic toxins in several ways such as low-dose effect, non-monotonic dose and trans-generational effects. This review aims to highlight the hidden burden of EDCs on human health and discusses the non-classical toxic properties of EDCs in an attempt to understand the magnitude of the exposome on human health. Present data on the environmental EDCs advocate that there may be associations between human exposure to EDCs and several undesirable health outcomes that warrants further human bio-monitoring of EDCs.

The Endocrine Disruption of Prenatal Phthalate Exposure in Mother and Offspring

Phthalates are a group of ubiquitous synthetic endocrine-disrupting chemicals. Fetal and neonatal periods are particularly susceptible to endocrine disorders, which prenatal exposure to phthalates causes. There is increasing evidence concerning the potential endocrine disrupting for phthalate exposure during pregnancy. This article aims to review the endocrine impairment and potential outcomes of prenatal phthalate exposure. Prenatal exposure phthalates would disrupt the levels of thyroid, sex hormone, and 25-hydroxyvitamin D in pregnant women or offspring, which results in preterm birth, preeclampsia, maternal glucose disorders, infant cryptorchidism, infant hypospadias, and shorter anogenital distance in newborns, as well as growth restriction not only in infants but also in early adolescence and childhood. The relationship of prenatal phthalate exposure with maternal and neonatal outcomes in human beings was often sex-specific associations. Because of the potentially harmful influence of prenatal phthalate exposure, steps should be taken to prevent or reduce phthalate exposure during pregnancy.

Endocrine-disrupting chemicals: implications for human health

Since reports published in 2015 and 2016 identified 15 probable exposure-outcome associations, there has been an increase in studies in humans of exposure to endocrine-disrupting chemicals (EDCs) and a deepened understanding of their effects on human health. In this Series paper, we have reviewed subsequent additions to the literature and identified new exposure-outcome associations with substantial human evidence. Evidence is particularly strong for relations between perfluoroalkyl substances and child and adult obesity, impaired glucose tolerance, gestational diabetes, reduced birthweight, reduced semen quality, polycystic ovarian syndrome, endometriosis, and breast cancer. Evidence also exists for relations between bisphenols and adult diabetes, reduced semen quality, and polycystic ovarian syndrome; phthalates and prematurity, reduced anogenital distance in boys, childhood obesity, and impaired glucose tolerance; organophosphate pesticides and reduced semen quality; and occupational exposure to pesticides and prostate cancer. Greater evidence has accumulated than was previously identified for cognitive deficits and attention-deficit disorder in children following prenatal exposure to bisphenol A, organophosphate pesticides, and polybrominated flame retardants. Although systematic evaluation is needed of the probability and strength of these exposure-outcome relations, the growing evidence supports urgent action to reduce exposure to EDCs.

Association between triclocarban and triclosan exposures and the risks of type 2 diabetes mellitus and impaired glucose tolerance in the National Health and Nutrition Examination Survey (NHANES 2013-2014)

BACKGROUND

There has been increasing interest in the concept that exposure to environmental chemicals may be contributing factors to epidemics of diabetes mellitus (DM). Triclocarban and triclosan (TCs) are synthetic antibacterial chemicals that are widely used in personal care products. Studies have shown that TCs are endocrine disruptors that alter metabolic conditions. However, it remains unclear whether exposure to TCs is a risk factor for impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM).

OBJECTIVE

We explored the hypothesis that TCs exposure is associated with an increased risk of IGT and T2DM.

METHOD

To test our hypothesis, we analyzed the U.S. National Health and Nutrition Examination Survey (NHANES) cross-sectional data from 2013 to 2014. IGT and T2DM were diagnosed based on an oral glucose tolerance test (OGTT) and the WHO standards. The levels of urinary TCs were measured using an HPLC-MS/MS method that NHANES investigators developed. The association between urinary TCs status and IGT and T2DM was examined separately in men and women using multivariable logistic regression models adjusted for age, race, BMI, education, ratio of family income to poverty, smoking, exercise and hypertension.

RESULTS

Nine hundred US participants (429 men and 471 women) were included in the analysis, of whom 242 (26.89%) were diagnosed with T2DM and 117 (13.00%) had IGT. Among women, there was a significant positive association between triclocarban, but not triclosan exposure and T2DM (OR: 1.79, 95% CI: 1.05, 2.05) after adjusting for potential confounding factors. Among men, no significant association between TCs exposure and IGT or T2DM was observed.

CONCLUSIONS

Triclocarban exposure may increase the risk of T2DM in the women, although additional studies are needed to confirm the results of this study and to investigate the underlying mechanisms.

Heightened susceptibility: A review of how pregnancy and chemical exposures influence maternal health

Pregnancy is a unique period when biological changes can increase sensitivity to chemical exposures. Pregnant women are exposed to multiple environmental chemicals via air, food, water, and consumer products, including flame retardants, plasticizers, and pesticides. Lead exposure increases risk of pregnancy-induced hypertensive disorders, although women's health risks are poorly characterized for most chemicals. Research on prenatal exposures has focused on fetal outcomes and less on maternal outcomes. We reviewed epidemiologic literature on chemical exposures during pregnancy and three maternal outcomes: preeclampsia, gestational diabetes, and breast cancer. We found that pregnancy can heighten susceptibility to environmental chemicals and women's health risks, although variations in study design and exposure assessment limited study comparability. Future research should include pregnancy as a critical period for women's health. Incorporating biomarkers of exposure and effect, deliberate timing and method of measurement, and consistent adjustment of potential confounders would strengthen research on the exposome and women's health.

Bisphenol A and Phthalates in Diet: An Emerging Link with Pregnancy Complications

Endocrine-disrupting chemicals (EDCs) are exogenous substances that are able to interfere with hormone action, likely contributing to the development of several endocrine and metabolic diseases. Among them, Bisphenol A (BPA) and phthalates contaminate food and water and have been largely studied as obesogenic agents. They might contribute to weight gain, insulin resistance and pancreatic β-cell dysfunction in pregnancy, potentially playing a role in the development of pregnancy complications, such as gestational diabetes mellitus (GDM), and adverse outcomes. Pregnancy and childhood are sensitive windows of susceptibility, and, although with not univocal results, preclinical and clinical studies have suggested that exposure to BPA and phthalates at these stages of life might have an impact on the development of metabolic diseases even many years later. The molecular mechanisms underlying this association are largely unknown, but adipocyte and pancreatic β-cell dysfunction are suspected to be involved. Remarkably, transgenerational damage has been observed, which might be explained by epigenetic changes. Further research is needed to address knowledge gaps and to provide preventive measure to limit health risks connected with exposure to EDCs.

RELATIONSHIP BETWEEN THE ENVIRONMENTAL ENDOCRINE DISRUPTOR BISPHENOL A AND DYSLIPIDEMIA: A FIVE-YEAR PROSPECTIVE STUDY

Objective: To investigate whether serum bisphenol A (BPA) concentration is related to the occurrence of dyslipidemia. Methods: A total of 574 adults were enrolled at baseline and followed up for 5 years. Concentrations of serum BPA, triglycerides (TGs), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol were measured. Dyslipidemia was defined as the existence of one or more of the following conditions: high-LDL-cholesterolemia (LDL ≥140 mg/dL), hypertriglyceridemia (TGs ≥150 mg/dL), or low-HDL-cholesterolemia (HDL <40 mg/dL). Participants were stratified into tertiles according to low, median, and high baseline serum BPA levels. Multivariable linear and logistic regression models were used. Data from baseline and follow-up were used for cross-sectional and longitudinal analyses, respectively. Results: In the cross-sectional analysis, compared to subjects in the low BPA tertile, those in the high BPA tertile showed a higher level of LDL cholesterol (108.1 ± 24.4 mg/dL versus 119.5 ± 26.9 mg/dL; P<.05) and a lower level of HDL cholesterol (46.2 ± 11.7 mg/dL versus 39.5 ± 7.5 mg/dL; P<.05). In multivariable linear regression models, Z-transformed BPA was positively associated with LDL cholesterol (β= 0.13, P = .002) and negatively associated with HDL cholesterol (β= -0.28; P<.001). After cross-sectionally adjusting for confounders, subjects in higher BPA exposure was associated with a higher prevalence of low-HDL-cholesterolemia. Longitudinally, in subjects without low-HDL-cholesterolemia at baseline, each SD increment in baseline BPA was associated with a higher incidence of low-HDL-cholesterolemia after adjustment for confounders (odds ratio [95% confidence interval; CI] 2.76, 95% CI 1.21, 6.29). Conclusion: Cross-sectionally, higher BPA exposure is associated with a higher prevalence of low-HDL-cholesterolemia. Longitudinally, baseline BPA is an independent predictor of the 5-year incidence of low-HDL-cholesterolemia. Abbreviations: BMI = body mass index; BPA = bisphenol A; CI = confidence interval; CVD = cardiovascular disease; EIMDS = environment, inflammation and metabolic diseases study; HDL = high density lipoprotein; LDL = low density lipoprotein; OR = odds ratio; PPAR = peroxisome proliferator-activated receptor; SBP = systolic blood pressure; TG = triglyceride; Z-BPA = Z-transformed bisphenol A.

Phthalate exposure and metabolic effects: a systematic review of the human epidemiological evidence

OBJECTIVE

We performed a systematic review of the epidemiology literature to identify the metabolic effects associated with phthalate exposure.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

Six phthalates were included in the review: di(2‑ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of metabolic effects in humans, and outcomes were selected for full systematic review based on data availability.

STUDY EVALUATION AND SYNTHESIS METHODS

Studies of diabetes and insulin resistance were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach; studies identified with a pre-defined critical deficiency were excluded. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework. Studies of obesity and renal effects received "screening level" reviews to determine whether full systematic review was warranted.

RESULTS

The primary outcomes reviewed here are (number of included/excluded studies in parentheses): type 2 diabetes (1/3), insulin resistance (13/3), and impaired glucose tolerance and blood glucose in pregnancy (4/2). For DEHP exposure, there was consistency among studies of insulin resistance and coherence with the single included study of diabetes, as well as an observed exposure-response gradient observed in a study of insulin resistance. This evidence is considered moderate. Similarly, for DBP and DIBP exposure, the evidence is considered moderate due to strong positive associations in the diabetes study and coherent results for insulin resistance. For DINP, BBP, and DEP, the evidence is considered slight. No association was reported in the single study of diabetes with BBP and DEP exposure (DINP was not investigated). The available evidence does indicate an association between exposure to these phthalates and insulin resistance, but the small number of studies and the lack of coherence with diabetes decreases confidence. The screening level reviews for obesity and renal effects determined that the currently available evidence is inadequate to assess the associations between these outcomes and phthalate exposure.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Overall, these results support that phthalate exposure at levels seen in human populations may have metabolic effects. Given the mechanistic support, the large effect sizes for incident diabetes in the single available study, and the coherence with insulin resistance, the association between phthalate exposure and diabetes risk should be considered when assessing the risks and costs of exposure to specific phthalates in humans. The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Unhealthy Levels of Phthalates and Bisphenol A in Mexican Pregnant Women with Gestational Diabetes and Its Association to Altered Expression of miRNAs Involved with Metabolic Disease

Several studies indicate that bisphenol A (BPA) and phthalates may have a role in the development of metabolic diseases using different molecular pathways, including epigenetic regulatory mechanisms. However, it is unclear whether exposure to these chemicals modifies serum levels of miRNAs associated with gestational diabetes mellitus (GDM) risk. In the present study, we evaluated the serum levels of miRNAs associated with GDM (miR-9-5p, miR-16-5p, miR-29a-3p and miR-330-3p) and urinary levels of phthalate metabolites (mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP) and mono(2-ethyl hexyl) phthalate (MEHP)) and bisphenol A in GDM patients and women without GDM during the second trimester of gestation. We observed higher levels of miR-9-5p, miR-29a-3p and miR-330-3p in sera of patients with GDM compared to non-diabetic subjects. Phthalates were detected in 97–100% of urine samples, while BPA only in 40%. Urinary MEHP and BPA concentrations were remarkably higher in both study groups compared to previously reported data. Unadjusted MEHP levels and adjusted BPA levels were higher in non-diabetics than in GDM patients (p = 0.03, p = 0.02). We found positive correlations between adjusted urinary MBzP levels and miR-16-5p expression levels (p < 0.05), adjusted MEHP concentrations and miR-29a-3p expression levels (p < 0.05). We also found negative correlations between unadjusted and adjusted MBP concentrations and miR-29a-3p expression levels (p < 0.0001, p < 0.05), unadjusted MiBP concentrations and miR-29a-3p expression levels (p < 0.01). Urinary MEHP levels reflect a striking exposure to di(2-ethylhexyl) phthalate (DEHP) in pregnant Mexican women. This study highlights the need for a regulatory strategy in the manufacture of several items containing endocrine disruptors in order to avoid involuntary ingestion of these compounds in the Mexican population.

Immunomodulatory effects of synthetic endocrine disrupting chemicals on the development and functions of human immune cells

Endocrine disrupting chemicals (EDCs) are added to food, cosmetics, plastic packages, and children's toys and have thus become an integral part of the human environment. In the last decade, there has been increasing interest in the effect of EDCs on human health, including their impact on the immune system. So far, researchers have proved that EDCs (e.g. bisphenols, phthalates, triclosan, phenols, propanil, tetrachlorodibenzo-p-dioxin, diethylstilbestrol, tributyltin (TBT), and parabens) affect the development, functions, and lifespan of immune cells (e.g., monocytes, neutrophils, mast cells, eosinophils, lymphocytes, dendritic cells, and natural killers). In this review, we have summarized the current knowledge of the multivariable influence of EDCs on immune cells and underlined the novel approach to EDC studies, including dose-dependent effects and low-dose effects. We discuss critically the possible relationship between exposure to EDCs and immunity related diseases (e.g. allergy, asthma, diabetes, and lupus). Moreover, based on the literature, we construct a model of possible mechanisms of EDC action on immune cells at cellular, molecular, and epigenetic levels.

Variations in repeated serum concentrations of UV filters, phthalates, phenols and parabens during pregnancy

BACKGROUND

Biobank serum samples from longitudinal mother-child cohorts have been used to estimate prenatal exposures to endocrine disrupting chemicals (EDCs). However, the knowledge about variations in serum concentrations of non-persistent chemicals during pregnancy is limited.

OBJECTIVE

To describe the within- and between-person variations in serum concentrations of non-persistent chemicals and changes over trimesters, including phthalate metabolites, parabens, phenols, and UV filters.

DESIGN

Longitudinal study with repeated blood samples from 128 healthy pregnant women during pregnancy.

SETTING

Population based study at a University Hospital in Copenhagen 1999-2001.

METHODS

503 repetitive prenatal serum samples from 128 pregnant women taken at approximately gestational week 12, 20, 30 and 40 were analyzed for 7 UV filters, 32 metabolites of 15 phthalate diesters, 8 phenols and 7 parabens by LC-MS/MS.

RESULTS

Ten of 32 phthalate metabolites from six out of 15 phthalate diesters, two of seven parabens, two of eight phenols and three of seven UV filters were measurable in more than half of the serum samples. Of these chemicals, mono‑ethyl phthalate (MEP), mono‑iso‑nonyl phthalate (MiNP), mono‑iso‑decyl phthalate (MiDP), 4‑methylbenzophenone (4‑MBP), 4‑hydroxybenzoephenone (4‑HBP) and n‑propyl paraben (nPrP) had intra-class correlation coefficients (ICC) above 0.4 in both adjusted and unadjusted analyses (0.427-0.795), indicating low within-person variation. The serum concentration of UV filters 4‑MBP and 4‑HBP significantly increased throughout pregnancy, also after adjusting for seasonal variation (4‑HBP: effect estimates 0.142-0.437, p < 0.001. 4‑MBP: effect estimates 0.156-0.458, p < 0.002.).

CONCLUSION

MEP, MiNP, MiDP, 4‑MBP, 4‑HBP and nPrP were measurable in >50% of serum samples and showed low within-person variation. Thus, it is possible with acceptable accuracy to evaluate maternal exposure during pregnancy for these non-persistent chemicals using one or more biobank serum samples. The here presented adjusted ICC values can in addition be applied as adjustment of residual variation in future studies that evaluate outcomes related to prenatal exposures.

Maternal urinary phthalate metabolites in relation to gestational diabetes and glucose intolerance during pregnancy

BACKGROUND

Phthalates are common plasticizer chemicals that have been linked to glucose intolerance in the general population, but there is only limited research on their association with gestational diabetes (GDM).

OBJECTIVE

We evaluated the association between 11 urinary phthalate metabolites and GDM, impaired glucose tolerance (IGT), and continuous blood glucose concentration during pregnancy in The Infant Development and Environment Study (TIDES). Based on prior study results, our primary analyses focused on monoethyl phthalate (MEP) in relation to our outcomes of interest.

STUDY DESIGN

We used multi-variable logistic regression to examine the odds of GDM and IGT in relation to an interquartile-range (IQR) increase in natural log (ln)-transformed, specific gravity (SG)-adjusted first trimester (T1) and average of T1 and third trimester (T3) ("T1T3avg") phthalate metabolite concentrations. We fit linear regression models to examine the percent change in blood glucose per IQR increase in ln-transformed, SG-adjusted T1 and T1T3avg phthalates. In sensitivity analyses, we examined interactions between exposure and race. We adjusted for maternal age, maternal body mass index, study center, race/ethnicity, parity, and gestational age at glucose testing.

RESULTS

In our sample of 705 pregnant women, we observed 60 cases of GDM, 90 cases of IGT, and an average GLT blood glucose of 113.6 ± 27.7 mg/dL. In our primary analysis, T1T3avg MEP was positively associated with GDM ([OR (95% CI) per IQR increase] T1T3avg MEP: 1.61 (1.10, 2.36)). In secondary analyses, most other phthalates were not found to be related to study outcomes, though some associations were noted. Sensitivity analyses indicated possible strong race-specific associations in Asians, though these results are based on a small sample size (n = 35).

CONCLUSION

In alignment with our a priori selection, we documented an association between T1T3avg MEP and GDM. Additional phthalate metabolites were also found to be linked to glucose intolerance, with possible stronger associations in certain racial/ethnic subgroups. Given the prevalence of phthalate exposures and the growing evidence of associations with metabolic outcomes, future studies should continue to examine this question in diverse cohorts of pregnant women, particularly in those who may be at higher risk for GDM and IGT.