Persistent organic pollutants in early pregnancy and risk of gestational diabetes mellitus

Polystyrene microplastics disturb maternal glucose homeostasis and induce adverse pregnancy outcomes

Pregnant women are a special group that is sensitive to adverse external stimuli, causing metabolic abnormalities and adverse pregnancy outcomes. Microplastics (MPs), an environmental pollutant widely used in various fields, can induce a variety of toxic responses in mammals. Recent studies verified an association between MPs and metabolic disorders. Our research built a gestational mouse model in which polystyrene microplastics (PS-MPs) of 1 μm size were consumed at concentrations of 0.1, 1, and 10 mg/L during pregnancy. Results indicated that PS-MPs induced placental malfunction and fetal growth retardation. Significant glucose disorders, decreased liver function, hepatic inflammation, and oxidative stress were also observed after PS-MPs exposure. The hepatic SIRT1/IRS1/PI3K pathway was inhibited in the 10 mg/L PS-MPs exposure group. Our study found that PS-MPs activated inflammatory response and oxidative stress by increasing hepatic lipopolysaccharide (LPS) that inhibited the hepatic SIRT1/IRS1/PI3K pathway, ultimately leading to insulin resistance, glucose metabolism disorders, and adverse pregnancy outcomes. This study provides a basis for preventing environment-related gestational diabetes and concomitant adverse pregnancy outcomes.

Endocrine disrupting chemicals: gestational diabetes and beyond

Gestational Diabetes Mellitus (GDM) has been on the rise for the last two decades along with the growing incidence of obesity. The ubiquitous use of Endocrine-Disrupting Chemicals (EDCs) worldwide has been associated with this increase in GDM incidence. Epigenetic modifications such as DNA methylation, histone acetylation, and methylation have been associated with prenatal exposure to EDCs. EDC exposure can also drive a sustained disruption of the hypothalamus-pituitary-thyroid axis and various other signaling pathways such as thyroid signaling, PPARγ signaling, PI3K-AKT signaling. This disruption leads to impaired glucose metabolism, insulin resistance as well as β-cell dysfunction, which culminate into GDM. Persistent EDC exposure in pregnant women also increases adipogenesis, which results in gestational weight gain. Importantly, pregnant mothers transfer these EDCs to the fetus via the placenta, thus leading to other pregnancy-associated complications such as intrauterine growth restriction (IUGR), and large for gestational age neonates. Furthermore, this early EDC exposure of the fetus increases the susceptibility of the infant to metabolic diseases in early life. The transgenerational impact of EDCs is also associated with higher vascular tone, cognitive aberrations, and enhanced susceptibility to lifestyle disorders including reproductive health anomalies. The review focuses on the impact of environmental toxins in inducing epigenetic alterations and increasing the susceptibility to metabolic diseases during pregnancy needs to be extensively studied such that interventions can be developed to break this vicious cycle. Furthermore, the use of EDC-associated ExomiRs from the serum of patients can help in the early diagnosis of GDM, thereby leading to triaging of patients based on increasing risk factor of the clinicopathological condition.

Persistent organic pollutant exposure as a risk factor of gestational diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Findings related to the association between persistent organic pollutants (POPs) and gestational diabetes mellitus (GDM) are inconclusive.

OBJECTIVES

To estimate the strength of the association between POP exposure and GDM in a systematic review with meta-analysis.

SEARCH STRATEGY

MEDLINE, Scopus and Web of Science were searched until July 2023.

SELECTION CRITERIA

Cohort and case-control studies analysing the association between POPs and GDM.

DATA COLLECTION AND ANALYSIS

We assessed the risk of bias using the Quality in Prognosis Studies scale (QUIPS). Standardised mean differences were pooled using random-effect models.

MAIN RESULTS

Sixteen articles including 12 216 participants were selected. The risk of bias was high in four articles (25%), moderate in 11 (68.75%) and low in one (6.25%). Small mean difference between GDM cases and controls was observed for PFHpA (0.26, 95% confidence interval [CI] 0.1-0.35, I2  = 0.0%), PCB180 (0.37, 95% CI 0.19-0.56; I2  = 25.3%), BDE47 (0.23, 95% CI 0.0-0.45, I2  = 0%), BDE99 (0.36, 95% CI 0.14-0.59; I2  = 0%), BDE100 (0.42, 95% CI 0.19-0.64; I2  = 0%) and HCB (0.22, 95% CI 0.01-0.42, I2  = 39.6%). No considerable difference was observed for the rest of POPs.

CONCLUSION

Small mean differences between GDM cases and controls were observed for some POPs. However, evidence shows mostly moderate quality and results were heterogeneous. Improved research methodology is needed to assess POPs and GDM risk.

Association of urinary polycyclic aromatic hydrocarbon metabolites with gestational diabetes mellitus and gestational hypertension among pregnant women in Southwest China: A cross-sectional study

The association of polycyclic aromatic hydrocarbons (PAHs) with gestational diabetes mellitus (GDM) and gestational hypertension during pregnancy has not yet been established. To investigate the association between PAH exposure and GDM and gestational hypertension, we conducted a cross-sectional study of 4206 pregnant women from the Zunyi birth cohort in southwestern China. Gas chromatography/mass spectrometry was used to detect the urinary levels of 10 monohydroxylated PAHs (OH-PAHs). GDM and gestational hypertension were diagnosed and the relevant information was documented by specialist obstetricians and gynecologists. Logistic regression and restricted cubic spline regression were employed to investigate their single and nonlinear associations. Stratified analyses of pregnancy and body mass index data were conducted to determine their moderating effects on the abovementioned associations. Compared with the first quartile of urinary ∑OH-PAHs, the third or fourth quartile in all study participants was associated with an increased risk of GDM (quartile 3: odds ratio [OR] = 1.35, 95% confidence interval [CI]: 1.03-1.77) and gestational hypertension (quartile 3: OR = 1.88, 95% CI: 1.26-2.81; quartile 4: OR = 1.58, 95% CI: 1.04-2.39), respectively. Nonlinear associations of 1-OH-PYR with GDM (cutoff level: 0.02 μg/g creatinine [Cr]) and 1-OH-PHE with gestational hypertension (cutoff level: 0.06 μg/g Cr) were also observed. In pregnant women with overweight or obesity, 1-OH-PHE and 3-OH-PHE were more strongly associated with gestational hypertension. Our results indicate that exposure to PAH during pregnancy may significantly increase the maternal risks of GDM and gestational hypertension; however, this finding still needs to be confirmed through larger-scale prospective studies and biological evidence.

Serum levels of polychlorinated biphenyls and polybrominated diphenyl ethers in early pregnancy and their associations with gestational diabetes mellitus

Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) are extensively present in humans and may disturb glucose metabolism during pregnancy. However, previous reports on the associations between PCBs/PBDEs levels and gestational diabetes mellitus (GDM) have been inconsistent. We performed a nested case-control study to measure the serum levels of 6 PCB and 7 PBDE congeners in early pregnancy, and to assess their associations with GDM risk and blood glucose levels. Totally, 208 serum samples (104 GDM cases and 104 controls) were included based on a prospective cohort which was carried out in Jiangsu province, China, from 2020 to 2022. The results showed that PCB-153 was the major PCB congener, whereas PBDE-47 was the predominant PBDE congener. The continuous concentrations of PCB-153, PBDE-28, and total PCB were significantly related to an increased risk of GDM, with adjusted ORs (95%CI) of 1.25 (1.04-1.50), 1.19 (1.02-1.39), and 1.37 (1.05-1.79), respectively. Potential dose-response relationships were also observed between serum levels of PCB-153 (P = 0.011), PBDE-28 (P = 0.028), total PCB (P = 0.048), and total PCB/PBDE (P = 0.010) and GDM risk. Moreover, PCB-153, PBDE-28 and total PCB levels were positively related to 1-h OGTT blood glucose (adjusted βPCB-153: 0.14, 95%CI: 0.00-0.28; adjusted βPBDE-28: 0.20, 95%CI: 0.08-0.32; adjusted βtotal PCB: 0.30, 95%CI: 0.09-0.50), whereas none of the PCBs/PBDEs were statistically related to fasting blood glucose and 2-h OGTT blood glucose (all P > 0.05). Further meta-analysis also supported the association of PCBs exposure with GDM risk. Our study provides further evidence that PCBs/PBDEs exposure may increase GDM risk during pregnancy.

Endocrine disrupting compounds in the baby's world - A harmful environment to the health of babies

Globally, there has been a significant increase in awareness of the adverse effects of chemicals with known or suspected endocrine-acting properties on human health. Human exposure to endocrine disrupting compounds (EDCs) mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Although it is difficult to assess the full impact of human exposure to EDCs, it is well known that timing of exposure is of importance and therefore infants are more vulnerable to EDCs and are at greater risk compared to adults. In this regard, infant safety and assessment of associations between prenatal exposure to EDCs and growth during infancy and childhood has been received considerable attention in the last years. Hence, the purpose of this review is to provide a current update on the evidence from biomonitoring studies on the exposure of infants to EDCs and a comprehensive view of the uptake, the mechanisms of action and biotransformation in baby/human body. Analytical methods used and concentration levels of EDCs in different biological matrices (e.g., placenta, cord plasma, amniotic fluid, breast milk, urine, and blood of pregnant women) are also discussed. Finally, key issues and recommendations were provided to avoid hazardous exposure to these chemicals, taking into account family and lifestyle factors related to this exposure.

Environmental Pollution and the Risk of Developing Metabolic Disorders: Obesity and Diabetes

To meet the increased need for food and energy because of the economic shift brought about by the Industrial Revolution in the 19th century, there has been an increase in persistent organic pollutants (POPs), atmospheric emissions and metals in the environment. Several studies have reported a relationship between these pollutants and obesity, and diabetes (type 1, type 2 and gestational). All of the major pollutants are considered to be endocrine disruptors because of their interactions with various transcription factors, receptors and tissues that result in alterations of metabolic function. POPs impact adipogenesis, thereby increasing the prevalence of obesity in exposed individuals. Metals impact glucose regulation by disrupting pancreatic β-cells, causing hyperglycemia and impaired insulin signaling. Additionally, a positive association has been observed between the concentration of endocrine disrupting chemicals (EDCs) in the 12 weeks prior to conception and fasting glucose levels. Here, we evaluate what is currently known regarding the link between environmental pollutants and metabolic disorders. In addition, we indicate where further research is required to improve our understanding of the specific effects of pollutants on these metabolic disorders which would enable implementation of changes to enable their prevention.

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.

Co-exposure of organophosphorus pesticides is associated with increased risk of type 2 diabetes mellitus in a Chinese population

OBJECTIVE

The epidemiological evidence of human exposure to organophosphorus pesticides (OPPs) with type 2 diabetes mellitus (T2DM) and prediabetes (PDM) is scarce. We aimed to examine the association of T2DM/PDM risk with single OPP exposure and multi-OPP co-exposure.

METHODS

Plasma levels of ten OPPs were measured using the gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) among 2734 subjects from the Henan Rural Cohort Study. We used generalized linear regression to estimate odds ratios (ORs) or β with 95% confidence intervals (CIs), and constructed quantile g-computation and Bayesian kernel machine regression (BKMR) models to investigate the association of OPPs mixture with the risk of T2DM and PDM.

RESULTS

High detection rates ranged from 76.35% (isazophos) to 99.17% (malathion and methidathion) for all OPPs. Several plasma OPPs concentrations were in positive correlation with T2DM and PDM. Additionally, positive associations of several OPPs with fasting plasma glucose (FPG) values and glycosylated hemoglobin (HbA1c) levels were observed. In the quantile g-computation, we identified significantly positive associations between OPPs mixtures and T2DM as well as PDM, and fenthion had the greatest contribution for T2DM, followed by fenitrothion and cadusafos. As for PDM, the increased risk was largely explained by cadusafos, fenthion, and malathion. Furthermore, BKMR models suggested that co-exposure to OPPs was linked to an increased risk of T2DM and PDM.

CONCLUSION

Our findings suggested that the individual and mixture of OPPs co-exposure were associated with an increased risk of T2DM and PDM, implying that OPPs might act an important role in the development of T2DM.

Assessment of organohalogenated pollutants in breast milk from the Czech Republic

This biomonitoring survey brings new information on the occurrence of a total of 94 organohalogenated pollutants in 231 human breast milk samples collected in 2019 and 2021 from women living in two regions of the Czech Republic (Karvina and Ceske Budejovice). This study aimed to evaluate the concentrations of 6 indicator polychlorinated biphenyls (PCBs), 10 organochlorine pesticides (OCPs), 34 halogenated flame retardants (HFRs), 29 perfluoroalkyl and polyfluoroalkyl substances (PFAS) and 15 polychlorinated naphthalenes (PCNs). PCBs, OCPs, most of HFRs and PCNs were identified/quantified by gas chromatography coupled to (tandem) mass spectrometry (GC-MS(/MS)), while PFAS, hexabromocyclododecane isomers (HBCD), brominated phenols, and tetrabromobisphenol A (TBBPA) by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The mean value of the sum of the 6 indicator PCBs was 123.12 nanogram per gram of lipid weight (ng g^-1 lw). Hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) were the most abundant OCPs, detected in 100 % (mean 11.8 ng g^-1 lw), 94.8 % (mean 6.1 ng g^-1 lw) and 100 % (mean 101.5 ng g^-1 lw) of samples, respectively. PCN congeners 20, 52 and 66 were detected in <1 % of the samples. The HFRs concentrations were relatively low compared to the levels of OCP; The detection rate of polybrominated diphenyl ethers (PBDEs, # 47, 99 and 153) ranged 21-68 % with a mean concentrations of 0.34 ng g^-1 lw - 0.42 ng g^-1 lw. PFAS concentrations were also low, with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) dominant in this group (means of 22 pg ml^-1 and 21 pg ml^-1, respectively). Our results confirmed the long-term trend of declining levels of banned POPs in Czech mothers. The amounts of PCBs and OCPs were higher in older breastfeeding primiparous women.

Associations of ozone exposure with gestational diabetes mellitus and glucose homeostasis: Evidence from a birth cohort in Shanghai, China

BACKGROUND

Associations between individual exposure to ozone (O₃) and gestational diabetes mellitus (GDM) have rarely been investigated, and critical windows of O₃ exposure for GDM have not been identified.

OBJECTIVES

We aimed to explore the associations of gestational O₃ exposure with GDM and glucose homeostasis as well as to identify the potential critical windows.

METHODS

A total of 7834 pregnant women were included. Individual O₃ exposure concentrations were evaluated using a high temporal-spatial resolution model. Each participant underwent an oral glucose tolerance test (OGTT) to screen for GDM between 24 and 28 gestational weeks. Multiple logistic and multiple linear regression models were used to estimate the associations of O₃ with GDM risks and with blood glucose levels of OGTT, respectively. Distributed lag nonlinear models (DLNMs) were used to estimate the critical windows of O₃ exposure for GDM.

RESULTS

Nearly 13.29 % of participants developed GDM. After controlling for covariates, we observed increased GDM risks per IQR increment of O₃ exposure in the first trimester (OR = 1.738, 95 % CI: 1.002-3.016) and the first two trimesters (OR = 1.576, 95 % CI: 1.005-2.473). Gestational O₃ exposure was positively associated with increased fasting blood glucose (the first trimester: β = 2.964, 95 % CI: 1.529-4.398; the first two trimesters: β = 1.620, 95 % CI: 0.436-2.804) and 2 h blood glucose (the first trimester: β = 6.569, 95 % CI: 1.775-11.363; the first two trimesters: β = 6.839, 95 % CI: 2.896-10.782). We also observed a concentration-response relationship of gestational O₃ exposure with GDM risk, as well as fasting and 2 h blood glucose levels. Additionally, 5-10 gestational weeks was identified as a critical window of O₃ exposure for GDM development.

CONCLUSION

In summary, we found that gestational O₃ exposure disrupts glucose homeostasis and increases the risk of GDM in pregnant women. Furthermore, 5-10 gestational weeks could be a critical window for the effects of O₃ exposure on GDM.

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.

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.

Association of abnormal-glucose tolerance during pregnancy with exposure to PM2.5 components and sources

Maternal exposure to PM_2.5 has been associated with abnormal glucose tolerance during pregnancy, but little is known about which constituents and sources are most relevant to glycemic effects. We conducted a retrospective cohort study of 1148 pregnant women to investigate associations of PM_2.5 chemical components with gestational diabetes mellitus (GDM) and impaired glucose tolerance (IGT) and to identify the most harmful sources in Heshan, China from January 2015 to July 2016. We measured PM_2.5 using filter-based method and analyzed them for 28 constituents, including carbonaceous species, water-soluble ions and metal elements. Contributions of PM_2.5 sources were assessed by positive matrix factorization (PMF). Logistic regression model was used to estimate composition-specific and source-specific effects on GDM/IGT. Random forest algorithm was applied to evaluate the relative importance of components to GDM and IGT. PM_2.5 total mass and several chemical constituents were associated with GDM and IGT across the early to mid-gestation periods, as were the PM_2.5 sources fossil fuel/oil combustion, road dust, metal smelting, construction dust, electronic waster, vehicular emissions and industrial emissions. The trimester-specific associations differed among pollutants and sources. The third and highest quartile of elemental carbon, ammonium (NH₄⁺), iron (Fe) and manganese (Mn) across gestation were consistently associated with higher odds of GDM/IGT. Maternal exposures to zinc (Zn), titanium (Ti) and vehicular emissions during the first trimester, and vanadium (V), nickel (Ni), road dust and fossil fuel/oil combustion during the second trimester were more important for GDM/IGT. This study provides important new evidence that maternal exposure to PM_2.5 components and sources is significantly related to elevated risk for abnormal glucose tolerance during pregnancy.

Protracted Impairment of Maternal Metabolic Health in Mouse Dams Following Pregnancy Exposure to a Mixture of Low Dose Endocrine-Disrupting Chemicals, a Pilot Study

Pregnancy, a period of increased metabolic demands coordinated by fluctuating steroid hormones, is an understudied critical window of disease susceptibility for later-life maternal metabolic health. Epidemiological studies have identified associations between exposures to various endocrine-disrupting chemicals (EDCs) with an increased risk for metabolic syndrome, obesity, and diabetes. Whether such adverse outcomes would be heightened by concurrent exposures to multiple EDCs during pregnancy, consistent with the reality that human exposures are to EDC mixtures, was examined in the current pilot study. Mouse dams were orally exposed to relatively low doses of four EDCs: (atrazine (10 mg/kg), bisphenol-A (50 µg/kg), perfluorooctanoic acid (0.1 mg/kg), 2,3,7,8-tetrachlorodibenzo-p-dioxin (0.036 µg/kg)), or the combination (MIX), from gestational day 7 until birth or for an equivalent 12 days in non-pregnant females. Glucose intolerance, serum lipids, weight, and visceral adiposity were assessed six months later. MIX-exposed dams exhibited hyperglycemia with a persistent elevation in blood glucose two hours after glucose administration in a glucose tolerance test, whereas no such effects were observed in MIX-exposed non-pregnant females. Correspondingly, MIX dams showed elevated serum low-density lipoprotein (LDL). There were no statistically significant differences in weight or visceral adipose; MIX dams showed an average visceral adipose volume to body volume ratio of 0.09, while the vehicle dams had an average ratio of 0.07. Collectively, these findings provide biological plausibility for the epidemiological associations observed between EDC exposures during pregnancy and subsequent maternal metabolic dyshomeostasis, and proof of concept data that highlight the importance of considering complex EDC mixtures based of off common health outcomes, e.g., for increased risk for later-life maternal metabolic effects following pregnancy.

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 the pesticide DDT and risk of diabetes and hypertension: Systematic review and meta-analysis of prospective studies

BACKGROUND

Experimental evidence suggests that p,p'-DDE might be involved in the development of diabetes and hypertension (HTN); however, the evidence in humans is inconclusive.

OBJECTIVE

To summarize the epidemiological evidence for the association of p,p'-DDT exposure and its breakdown products with the risk of diabetes and HTN from prospective studies.

METHODS

We performed a systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Eligible studies (prospective) were search in PubMed, Web of Science, EBSCO, and SciELO databases (July 11, 2020). Different search algorithms were used for diabetes and HTN. Pooled odds ratios (ORs) were estimated from meta-analysis with random effects for each exposure and outcome.

RESULTS

A total of 23 prospective studies were included in this review, 16 assessed diabetes and seven HTN; very few measured p,p'-DDT. Exposure to p,p'-DDE was associated with a slightly increased risk of type 2 diabetes (T2D) (pooled OR = 1.44; 95%CI: 1.00, 2.07; p = 0.049) and HTN (pooled OR = 1.21; 95%CI: 1.07, 1.38). Dose-response meta-analysis suggested a non-linear relation between p,p'-DDE and T2D. Exposure to p,p'-DDE was not associated with gestational diabetes (pooled OR = 1.01; 95%CI: 0.94, 1.09); similarly, p,p'-DDT was not associated with T2D (pooled OR = 1.03; 95%CI: 0.79, 1.35).

CONCLUSIONS

Evidence from prospective studies suggests that exposure to p,p'-DDE, the main breakdown product of p,p'-DDT, might increase the risk of developing T2D; such increase may be apparent only at low levels. Exposure to p,p'-DDE may also increase the risk of having HTN; however, further evidence is required.

Assessment of epigenotoxic profiles of Dongjiang River: A comprehensive of chemical analysis, in vitro bioassay and in silico approach

This research explored the occurrence, epigenetic toxic profiling and main toxic pollutants of POPs in surface water of Dongjiang River, southern China. The concentrations of selected POPs including polycyclic aromatic hydrocarbons (PAHs), endocrine disrupting chemicals (EDCs), phthalate esters (PAEs) and polybrominated diphenyl ethers (PBDEs) of surface water from 18 sites were investigated. ∑₁₆PAHs and ∑₄EDCs were at a moderate level, while ∑₆PAEs and ∑₆PBDEs had low pollution levels. PAHs, EDCs and PAEs showed higher concentrations in dry season than those in wet season, and the loading of selected POPs in tributaries was higher than those in mainstream due to intensive manufactures and lower runoff volume. Moreover, activities of DNA methyltransferase (DNMT)1, histone deacetylase (HDAC2, HDAC8) were confirmed to be sensitive indicators for epigenetic toxicity. The DNMT1-mediated epigenetic equivalency toxicity of organic extracts in Dongjiang River were more serious than those of HDAC2 and HDAC8. Correlation analysis shown binding affinity between POPs and DNMT1, HDAC2 and HDAC8 could be regarded as toxic equivalency factors. Risk assessment suggested that 4-nonylphenol and bisphenol A were the largest contributors to epigenetic risk. This study is the first attempt to quantify epigenetic toxicity and epigenetic risk evaluation of river water.

Identification and prioritization of the potent components for combined exposure of multiple persistent organic pollutants associated with gestational diabetes mellitus

Persistent organic pollutants (POPs) remain a major point of concern worldwide, and surveillance monitoring of these contaminants presents a significant challenge. Here, we conducted an assessment of combined exposure to multiple POPs components [10 perfluoroalkyl acids (PFAAs), seven polybrominated diphenyl ethers (PBDEs), six polychlorinated biphenyls (PCBs) and 29 dioxin-like compounds (DLCs)] in relation to gestational diabetes mellitus (GDM) risk, and determined the identification and prioritization of potent components in these POPs mixtures. The results indicated a significant mixture effect and the combined exposure index estimated from multiple POPs components was associated with GDM and glucose homeostasis (P < 0.001). Based on the mixture effects on GDM, the procedure of prioritization identified DLCs as the components of the greatest concern, although at the lowest body burden in the population compared with PBDEs, PFAAs, and PCBs. For glucose homeostasis, BDE-153 was the chemical of top-ranked priority of concern. The final effect-based prioritized list of POPs was DLCs > PBDEs >PFAAs > PCBs. This prioritization is important for developing a more cost-effective regulation framework focusing on the POPs components of the greatest concern to human health.

Association between placenta concentrations polybrominated and polychlorinated biphenyls and gestational diabetes mellitus: a case-control study in northwestern Spain

Exposure to persistent organic pollutants begins in uterine life. The study was conducted to evaluate associations between gestational diabetes mellitus and the presence of persistent organic pollutants in placenta samples. They were derived from a birth cohort study in Ourense (NW Spain). Selective pressurized liquid extraction methodologies were used to determine targeted persistent organic pollutants in placenta samples. Cleanup of extracts was performed by solid-phase extraction using EZ-POP cartridges and detection by gas chromatography coupled to tandem mass spectrometry. Statistical calculations were performed by comparing the values obtained in the case and control groups. Statistical significance was considered as p < 0.050. Results: The concentrations of several congeners of polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB) presented lower levels in the placentas of expectant mothers with gestational diabetes mellitus when comparing them to the control cohort. This difference was statistically significant. It was revealed that this association was independent of obesity, age, parity, amenorrhoea at birth, or a family history of diabetes mellitus. To the best of our knowledge, this paper reported an inverse relationship between PBDE and PCB levels in placenta and gestational diabetes mellitus for the first time. We believe this may open a door to future studies in this field.

Persistent organic pollutants and maternal glycemic outcomes in a diverse pregnancy cohort of overweight women

BACKGROUND

Animal and human studies suggest certain persistent organic pollutants (POPs) may impact glucose metabolism; however, few epidemiologic studies have examined environmental determinants of glycemic outcomes during pregnancy. Our objective is to evaluate associations between exposures to individual and mixture of POPs and measures of prenatal fasting glucose, insulin, and insulin resistance during pregnancy in overweight women.

METHODS

A cohort of overweight and obese pregnant women (N = 95) was recruited from California. Blood samples were collected during late first or second trimester (median = 16 weeks' gestation; range = 10-24 weeks). Exposures included serum concentrations of polybrominated diphenyl ethers (PBDEs) and hydroxylated metabolites (OH-PBDEs), polychlorinated biphenyls (PCBs), and poly- and perfluoroalkyl substances (PFASs). Outcomes included serum concentrations of fasting plasma glucose, fasting plasma insulin, and calculated homeostatic model assessment of insulin resistance (HOMA-IR). Generalized linear models were used to evaluate cross-sectional associations between individual and aggregate POPs and mean percent difference in fasting glucose, fasting insulin, and HOMA-IR. Bayesian kernel machine regression (BKMR) was used to assess the relative importance of each exposure to the association with our outcomes, using conditional and group posterior inclusion probabilities (PIPs).

RESULTS

Study participants were racially/ethnically diverse and nearly half were below the federal poverty level. Across PBDEs and OH-PBDEs, the direction of associations with fasting glucose, fasting insulin and HOMA-IR were varied. A doubling of PCB-138, PCB-153, PCB-180, and ∑PCBs concentrations was associated with a 2.10% mmol/L (95%CI: 0.49%, 3.74%), 2.10% mmol/L (95%CI: -0.14%, 4.39%), 2.10% mmol/L (95%CI: 0.12%, 4.12%), and 2.81% mmol/L (95%CI: 0.38%, 5.31%) increase in fasting glucose, respectively. Exposure to individual PCBs was positively associated with both fasting insulin and HOMA-IR. All PFAS were inversely associated with fasting glucose, fasting insulin, and HOMA-IR. In BKMR models of fasting glucose, all four chemical classes were important contributors to the overall mixture, with PFASs identified as the most important contributor.

DISCUSSION

Prenatal PCB exposure was positively associated while certain PBDE and PFAS analytes were inversely associated with fasting glucose concentrations in overweight women. Further examination of the relationship between POPs exposure and glycemic functioning in a larger study population of women during pregnancy is warranted.

Contamination of polychlorinated biphenyls in honey from the Brazilian state of Rio Grande do Sul

Persistent organic pollutants are characterised by their chemical structure, environmental persistence and toxicity to human and wildlife populations. The production of these chemicals is regulated and restricted. However, they continue to be detected in the environment. In this study, the occurrence of 11 congeners of polychlorinated biphenyls (PCBs 28, 52, 77, 81, 101, 118, 126, 138, 153, 169, and 180) was investigated in 90 honey samples produced in the Brazilian state of Rio Grande do Sul. The samples were from different municipalities, production systems and floral origins. Extraction was performed using the modified QuEChERS method (Quick, Easy, Cheap, Effective, Rugged and Safe) followed by gas chromatography with micro-electron capture detector. The results showed the presence of four congeners (PCBs 28, 77, 81, 101) in 15 honey samples confirming the environmental contamination in Southern Brazil. Among the contaminated samples, no significant differences were identified regarding the production system and floral origin.

Lactational exposure to polychlorinated biphenyls is higher in overweight /obese women and associated with altered infant growth trajectory: A pilot study

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Human milk levels of PCBs are higher in mothers with overweight and obesity.

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Lactational exposure to PCBs is associated with alterations in development.

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Lactational expsures to PCBs in human milk are associated with slower infant growth patterns.

Background

Infant exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may contribute to developmental programming of long-term metabolic disease risk. PCBs persist given their lipophilicity and long half-lives, allowing them to bio-accumulate in adipose tissue. These compounds can then be excreted into maternal milk resulting in infant exposure.

Objective

To determine the level of PCBs in milk from mothers with pre-pregnancy overweight and obese (OW/OB) versus normal weight status (NW) and evaluate the association of milk PCB levels with infant growth over the first 6 months of life.

Methods

A pilot study of a subset of milk samples from mothers with NW (pre-pregnancy body mass index (BMI) < 25 kg/m², n = 11) and OW/OB (pre-pregnancy BMI ≥ 25 kg/m², n = 8) were examined approximately 2-weeks postpartum. PCB congeners 138 + 163, 132 + 153, 180, and the sum were measured using gas chromatography/mass spectrometry and adjusted for milk fat content. Infant growth was monitored from birth to 6 months for weight-for-age (WFA), length-for-age (LFA), weight-for-length (WFL), head circumference-for-age (HCA), and associations with milk PCB content determined using linear mixed modeling.

Results

Total milk fat content did not differ by maternal weight status (p = 0.88). Milk from mothers with OW/OB had significantly higher PCB sum (p = 0.02) and PCB 138 + 163 (p = 0.03). PCB 132 + 153 (β −0.0008, p = 0.0218), PCB 180 (β −0.0010, p = 0.0279), and PCB sum (β −0.0006, p = 0.0138) were negatively associated with HCA Z-score growth to 6 months. PCB 180 was negatively associated with infant WFA (β −0.0015, p = 0.0058) and WFL Z-score (β −0.0016, p = 0.0263) to 6 months. There were no associations of PCB sum content with WFL, LFA, WFL Z-score over the first 6 months of life.

Conclusions

Maternal overweight and obesity are associated with higher levels of total PCB congeners (132, 138, 153, 163, 180) in human milk. PCB congeners have negative associations with infant head circumference and weight trajectory over the first 6 months of life.

Female mice exposed to low doses of dioxin during pregnancy and lactation have increased susceptibility to diet-induced obesity and diabetes

Objective

Exposure to persistent organic pollutants is consistently associated with increased diabetes risk in humans. We investigated the short- and long-term impact of transient low-dose dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) exposure during pregnancy and lactation on glucose homeostasis and beta cell function in female mice, including their response to a metabolic stressor later in life.

Methods

Female mice were injected with either corn oil (CO; vehicle control) or 20 ng/kg/d TCDD 2x/week throughout mating, pregnancy and lactation, and then tracked for 6–10 weeks after chemical exposure stopped. A subset of CO- and TCDD-exposed dams was then transferred to a 45% high-fat diet (HFD) or remained on a standard chow diet for an additional 11 weeks to assess the long-term effects of TCDD on adaptability to a metabolic stressor. To summarize, female mice were transiently exposed to TCDD and then subsequently tracked beyond when TCDD had been excreted to identify lasting metabolic effects of TCDD exposure.

Results

TCDD-exposed dams were hypoglycemic at birth but otherwise had normal glucose homeostasis during and post-TCDD exposure. However, TCDD-exposed dams on a chow diet were modestly heavier than controls starting 5 weeks after the last TCDD injection, and their weight gain accelerated after transitioning to a HFD. TCDD-exposed dams also had an accelerated onset of hyperglycemia, impaired glucose-induced plasma insulin levels, reduced islet size, increased MAFA^-ve beta cells, and increased proinsulin accumulation following HFD feeding compared to controls. Overall, our study demonstrates that low-dose TCDD exposure during pregnancy has minimal effects on metabolism during the period of active exposure, but has detrimental long-term effects on metabolic adaptability to HFD feeding.

Conclusions

Our study suggests that transient low-dose TCDD exposure in female mice impairs metabolic adaptability to HFD feeding, demonstrating that dioxin exposure may be a contributing factor to obesity and diabetes pathogenesis in females.

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Female mice exposed to TCDD during pregnancy are hypoglycemic at birth.

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TCDD exposure promotes weight gain long after exposure ceases.

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TCDD-exposed dams fed a high-fat diet have accelerated onset of glucose intolerance.

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TCDDHFD dams have defects in islet morphology and beta cell function.

Environmental chemical burden in metabolic tissues and systemic biological pathways in adolescent bariatric surgery patients: A pilot untargeted metabolomic approach

BACKGROUND

Advances in untargeted metabolomic technologies have great potential for insight into adverse metabolic effects underlying exposure to environmental chemicals. However, important challenges need to be addressed, including how biological response corresponds to the environmental chemical burden in different target tissues.

AIM

We performed a pilot study using state-of-the-art ultra-high-resolution mass spectrometry (UHRMS) to characterize the burden of lipophilic persistent organic pollutants (POPs) in metabolic tissues and associated alterations in the plasma metabolome.

METHODS

We studied 11 adolescents with severe obesity at the time of bariatric surgery. We measured 18 POPs that can act as endocrine and metabolic disruptors (i.e. 2 dioxins, 11 organochlorine compounds [OCs] and 5 polybrominated diphenyl ethers [PBDEs]) in visceral and subcutaneous abdominal adipose tissue (vAT and sAT), and liver samples using gas chromatography with UHRMS. Biological pathways were evaluated by measuring the plasma metabolome using high-resolution metabolomics. Network and pathway enrichment analysis assessed correlations between the tissue-specific burden of three frequently detected POPs (i.e. p,p'-dichlorodiphenyldichloroethene [DDE], hexachlorobenzene [HCB] and PBDE-47) and plasma metabolic pathways.

RESULTS

Concentrations of 4 OCs and 3 PBDEs were quantifiable in at least one metabolic tissue for > 80% of participants. All POPs had the highest median concentrations in adipose tissue, especially sAT, except for PBDE-154, which had comparable average concentrations across all tissues. Pathway analysis showed high correlations between tissue-specific POPs and metabolic alterations in pathways of amino acid metabolism, lipid and fatty acid metabolism, and carbohydrate metabolism.

CONCLUSIONS

Most of the measured POPs appear to accumulate preferentially in adipose tissue compared to liver. Findings of plasma metabolic pathways potentially associated with tissue-specific POPs concentrations merit further investigation in larger populations.

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.

Maternal plant-based diet during gestation and pregnancy outcomes

PURPOSE

We aimed to explore the association of vegetarian-vegan diets and pregnancy outcomes.

METHODS

A retrospective, web-based study conducted in 2017. Women who delivered < 4 years prior to enrolment where eligible to participate. Participants were allocated to 3 groups based on their self-reported diet during pregnancy: omnivores, vegetarians or vegans. Outcomes of interest including birthweight centile, small for gestational age (SGA), large for gestational age (LGA), preterm birth (PTB), maternal excessive weight gain (EWG) and gestational diabetes (GDM) were compared between the groups.

RESULTS

Overall, 1419 women of which 234 vegans (16.5%), 133 vegetarian (9.4%) and 1052 omnivores (74.1%) were included in final analysis. Maternal vegan diet during pregnancy was associated with a lower birth weight centile as compared to omnivores (42.6 ± 25.9 vs. 52.5 ± 27.0 P < 0.001), a greater adjusted odds ratio (aOR) for SGA (aOR = 1.74; 95% CI 1.05, 2.86) but not with the risk of LGA (aOR = 0.55; 95% CI 0.30, 1.00). Further adjustment for BMI showed similar but nonsignificant associations for SGA and LGA as compared to the omnivore group. Vegan diet was associated with lower risk for maternal EWG (aOR = 0.61; 95% CI 0.44, 0.86) and modest nonsignificant association with GDM (aOR = 0.54 95% CI 0.28, 1.03) which was further attenuated by adjustment for pre-pregnancy BMI. Maternal diet group was not associated with the risk of PTB or low birth weight.

CONCLUSIONS

Maternal vegan diet is a protective factor from EWG but associated with a higher risk for SGA and lower birth weight centile. The association between vegan diet and fetal growth was mediated by maternal BMI.

Severe dioxin-like compound (DLC) contamination in e-waste recycling areas: An under-recognized threat to local health

Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.

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.

Examining Reproductive Health Outcomes in Females Exposed to Polychlorinated Biphenyl and Polybrominated Biphenyl

In 1973, accidental contamination of Michigan livestock with polybrominated biphenyls (PBBs) led to the establishment of a registry of exposed individuals that have been followed for > 40 years. Besides being exposed to PBBs, this cohort has also been exposed to polychlorinated biphenyls (PCBs), a structurally similar class of environmental pollutants, at levels similar to average US exposure. In this study, we examined the association between current serum PCB and PBB levels and various female reproductive health outcomes to build upon previous work and inconsistencies. Participation in this cross-sectional study required a blood draw and completion of a detailed health questionnaire. Analysis included only female participants who had participated between 2012 and 2015 (N = 254). Multivariate linear and logistic regression models were used to identify associations between serum PCB and PBB levels with each gynecological and infertility outcome. Additionally, a generalized estimating equation (GEE) model was used to evaluate each pregnancy and birth outcome in order to account for multiple pregnancies per woman. We controlled for age, body mass index, and total lipid levels in all analyses. A p-value of <0.05 was used for statistical significance. Among the women who reported ever being pregnant, there was a significant negative association with higher total PCB levels associating with fewer lifetime pregnancies ( β = −0.11, 95% CI = −0.21 to −0.005, p = 0.04). There were no correlations between serum PCB levels and the self-reported gynecological outcomes (pelvic inflammatory disease, endometriosis, polycystic ovarian syndrome, or uterine fibroids). No associations were identified between serum PCB levels and the prevalence of female infertility in women reporting ever having sexual intercourse with a male partner. There were no associations identified between serum PCB levels and pregnancy outcomes (singleton live births or miscarriages) or birth outcomes (preterm birth, birth weight, birth defects, hypertensive disorders of pregnancy, or gestational diabetes). PBB was not associated with any outcome. Further research is needed to determine if and how PCB may reduce pregnancy number.

Persistent Organic Pollutants in Food: Contamination Sources, Health Effects and Detection Methods

Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects. To ensure food safety and protect human health from POPs, it is critical to achieve a better understanding of POP pathways into food and develop strategies to reduce human exposure. POPs could present in food in the raw stages, transferred from the environment or artificially introduced during food preparation steps. Exposure to these pollutants may cause various health problems such as endocrine disruption, cardiovascular diseases, cancers, diabetes, birth defects, and dysfunctional immune and reproductive systems. This review describes potential sources of POP food contamination, analytical approaches to measure POP levels in food and efforts to control food contamination with POPs.

Determinants of persistent organic pollutant (POP) concentrations in human breast milk of a cross-sectional sample of primiparous mothers in Belgium

BACKGROUND

Bio-accumulation of persistent organic pollutants (POPs) in the environment and in the food chain can lead to high pollutant concentrations in human fat-containing tissues and breast milk.

OBJECTIVES

We aimed to identify the maternal characteristics that determined POP concentrations in breast milk of primiparous mothers in Belgium.

METHODS

Breast milk samples were obtained from a cross-sectional sample of 206 primiparous mothers in 2014. POP concentrations in breast milk samples were determined by GC-ECNI-MS and GC-EI-MS/MS depending on the analytes' sensitivity. Associations between POP concentrations in breast milk and potential determinants were investigated using two-way contingency tables and multivariable generalized linear models.

RESULTS

Fifteen of the 23 screened POPs were detected in the breast milk samples. Four organochlorine compounds (p,p'-DDT, p,p'-DDE, HCB and β-HCH) and two brominated flame retardant congeners (BDE-47, BDE-153) were detected at concentrations above the limit of quantification in >50% of the breast milk samples. Maternal age and BMI were usually associated with higher POP concentrations. Rural residency and consumption of home-produced eggs, fatty fish and fish oil supplements were associated with higher concentrations of DDT and DDE. Consumption of fatty fish and being breastfed during childhood were associated with higher concentrations of HCB and β-HCH. Fish oil supplements and home-produced eggs were associated with higher concentrations of BDEs, but for BDE congeners exposure routes other than diet require further investigation.

CONCLUSIONS

Dietary and non-dietary determinants predict individual POP concentrations in breast milk.

Serum concentrations and detection rates of selected organochlorine pesticides in a sample of Greek school-aged children with neurodevelopmental disorders

Prospective studies indicate that the exposure to organochlorine pesticides (OCPs) during fetal life, infancy, and early childhood may be associated with features of neurodevelopmental disorders in children. However, few studies have investigated the concentrations of serum OCPs in children with categorically diagnosed neurodevelopmental disorders. The aim of this study was to assess the concentrations and detection rates of dichlorodiphenyltrichloroethane (DDT) metabolites, hexachlorocyclohexane (HCH) isomers, cyclodienes, and methoxychlor in serum samples of children with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and specific learning disorder (SLD), all of normal intelligence, compared to typically developing controls (TD). In total, 114 schoolchildren, aged 6-13 years old, were assessed and distributed into four groups: ASD (n = 39), ADHD (n = 21), SLD (n = 32), and TD (n = 18). Each clinical group was compared to the TD group. Concentrations of serum OCPs were determined by gas chromatography and are presented as ng/g lipid. Concentrations of β-HCH, the sum of HCH isomers, and o,p'-DDD were significantly higher in ASD children: ASD vs. TD (mean ± SD): 10.5 ± 7.7 vs. 6.1 ± 4.0, (p = 0.049); 12.0 ± 10.3 vs. 6.6 ± 4.0, (p = 0.025); 7.4 ± 6.5 vs. 2.8 ± 2.3, (p = 0.0019), respectively. The detection rates of p,p'-DDT, at least one substance from DDTs detected, and the cyclodiene heptachlor epoxide, were significantly lower in the ASD group: ASD vs. TD: 12.8% vs. 38.9%, (p = 0.037); 69.2% vs. 94.4%, (p = 0.044); 10.3% vs. 38.9%, (p = 0.026), respectively. No significant differences between the ADHD or SLD groups and the TD group were observed. We demonstrated higher serum concentrations and lower detection rates of selected OCPs in ASD than TD children. Our results add to potential neurodevelopmental concerns surrounding OCPs and provide evidence of specificity in the relations between HCHs and ASD.

Gut microbiota characterization and lipid metabolism disorder found in PCB77-treated female mice

Although the production of polychlorinated biphenyl 77 (PCB77) has already been banned globally, PCB77 is still used for a wide range of commercial purposes. Previous evidence has demonstrated that the PCB77 administration should be responsible for the gut microbiota variations and the host health risk. However, the host disorders and bacterial functions involved in PCB77 exposure remain largely unknown. Few studies have been performed to illuminate the correlation between the bacterial functions and disorders. Furthermore, it is urgently needed to find specific strains as potential biomarkers to monitor PCB77 pollution and associated disorders. This study was designed to investigate the effects of PCB77 on gut microbiota and induced disorders in female mice. Obtained results indicated that PCB77 exposure induced gut microbiota dysbiosis, obesity, hyperlipidemia, hepatic lipid accumulation, and liver injury in mice. Functional prediction based on the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) algorithm showed that exposure to PCB77 weakened the bacterial functions relating to lipid and energy metabolism, and immune system disease. Experimental findings were consistent with the result of the PICRUSt functional prediction. Importantly, three PCB77-associated bacterial taxa were screened out as potential biomarkers for the assessment of PCB77 pollution. This study provides previously unknown knowledge linking PCB77 administration, gut microbiota functional profile and lipid abnormalities, which is of important clinical significance for therapies treating PCB77-associated diseases.

Persistent organic pollutants and gestational diabetes: A multi-center prospective cohort study of healthy US women

BACKGROUND

Persistent organic pollutants (POPs) are linked with insulin resistance and type-2 diabetes (T2D) in the general population. However, their associations with gestational diabetes (GDM) are inconsistent.

OBJECTIVE

We prospectively evaluated the associations of POPs measured in early pregnancy with GDM risk. We also assessed whether pre-pregnancy BMI (ppBMI) and family history of T2D modify this risk.

METHODS

In NICHD Fetal Growth Study, Singletons, we measured plasma concentration of 76 POPs, including 11 organochlorine pesticides (OCPs), 9 polybrominated diphenylethers (PBDEs), 44 polychlorinated biphenyls (PCBs), and 11 per-and polyfluoroalkyl substances (PFAS) among 2334 healthy non-obese women at 8-13 weeks of gestation. GDM was diagnosed by Carpenter and Coustan criteria. We constructed chemical networks using a weighted-correlation algorithm and examined the associations of individual chemical and chemical networks with GDM using multivariate Poisson regression with robust variance.

RESULTS

Higher concentrations of PCBs with six or more chlorine atoms were associated with increased risk of GDM in the overall cohort (risk ratios [RRs] range: 1.08-1.13 per 1-standard deviation [SD] increment) and among women with a family history of T2D (RRs range: 1.08-1.48 per 1-SD increment) or normal ppBMI (RRs range: 1.08-1.22 per 1-SD increment). Similar associations were observed for the chemical network comprised of PCBs with ≥6 chlorine atoms and the summary measure of total PCBs and non-dioxin like PCBs (138, 153, 170, 180). Furthermore, four PFAS congeners - perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and perfluorododecanoic acid (PFDoDA) - showed significant positive associations with GDM among women with a family history of T2D (RRs range:1.22-3.18 per 1-SD increment), whereas BDE47 and BDE153 showed significant positive associations among women without a family history of T2D.

CONCLUSIONS

Environmentally relevant levels of heavily chlorinated PCBs and some PFAS and PBDEs were positively associated with GDM with suggestive effect modifications by family history of T2D and body adiposity status.

Effects of cross-fostering and developmental exposure to mixtures of environmental contaminants on hepatic gene expression in prepubertal 21 days old and adult male Sprague-Dawley rats

The notion that adverse health effects produced by exposure to environmental contaminants (EC) may be modulated by the presence of non-chemical stressors is gaining attention. Previously, our lab demonstrated that cross-fostering (adoption of a litter at birth) acted as a non-chemical stressor that amplified the influence of developmental exposure to EC on the glucocorticoid stress-response in adult rats. Using liver from the same rats, the aim of the current study was to investigate whether cross-fostering might also modulate EC-induced alterations in hepatic gene expression profiles. During pregnancy and nursing, Sprague-Dawley dams were fed cookies laced with corn oil (control, C) or a chemical mixture (M) composed of polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), and methylmercury (MeHg), at 1 mg/kg/day. This mixture simulated the contaminant profile reported in maternal human blood. At birth, some control and M treated litters were cross-fostered to form two additional groups with different biological/nursing mothers (CC and MM). The hepatic transcriptome was analyzed by DNA microarray in male offspring at postnatal days 21 and 78-86. Mixture exposure altered the expression of detoxification and energy metabolism genes in both age groups, but with different sets of genes affected at day 21 and 78-86. Cross-fostering modulated the effects of M on gene expression pattern (MM vs M), as well as expression of energy metabolism genes between control groups (CC vs C). In conclusion, while describing short and long-term effects of developmental exposure to EC on hepatic transcriptomes, these cross-fostering results further support the consideration of non-chemical stressors in EC risk assessments.

Methodological issues in a prospective study on plasma concentrations of persistent organic pollutants and pancreatic cancer risk within the EPIC cohort

BACKGROUND

The use of biomarkers of environmental exposure to explore new risk factors for pancreatic cancer presents clinical, logistic, and methodological challenges that are also relevant in research on other complex diseases.

OBJECTIVES

First, to summarize the main design features of a prospective case-control study -nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort- on plasma concentrations of persistent organic pollutants (POPs) and pancreatic cancer risk. And second, to assess the main methodological challenges posed by associations among characteristics and habits of study participants, fasting status, time from blood draw to cancer diagnosis, disease progression bias, basis of cancer diagnosis, and plasma concentrations of lipids and POPs. Results from etiologic analyses on POPs and pancreatic cancer risk, and other analyses, will be reported in future articles.

METHODS

Study subjects were 1533 participants (513 cases and 1020 controls matched by study centre, sex, age at blood collection, date and time of blood collection, and fasting status) enrolled between 1992 and 2000. Plasma concentrations of 22 POPs were measured by gas chromatography - triple quadrupole mass spectrometry (GC-MS/MS). To estimate the magnitude of the associations we calculated multivariate-adjusted odds ratios by unconditional logistic regression, and adjusted geometric means by General Linear Regression Models.

RESULTS

There were differences among countries in subjects' characteristics (as age, gender, smoking, lipid and POP concentrations), and in study characteristics (as time from blood collection to index date, year of last follow-up, length of follow-up, basis of cancer diagnosis, and fasting status). Adjusting for centre and time of blood collection, no factors were significantly associated with fasting status. Plasma concentrations of lipids were related to age, body mass index, fasting, country, and smoking. We detected and quantified 16 of the 22 POPs in more than 90% of individuals. All 22 POPs were detected in some participants, and the smallest number of POPs detected in one person was 15 (median, 19) with few differences by country. The highest concentrations were found for p,p'-DDE, PCBs 153 and 180 (median concentration: 3371, 1023, and 810 pg/mL, respectively). We assessed the possible occurrence of disease progression bias (DPB) in eight situations defined by lipid and POP measurements, on one hand, and by four factors: interval from blood draw to index date, tumour subsite, tumour stage, and grade of differentiation, on the other. In seven of the eight situations results supported the absence of DPB.

CONCLUSIONS

The coexistence of differences across study centres in some design features and participant characteristics is of relevance to other multicentre studies. Relationships among subjects' characteristics and among such characteristics and design features may play important roles in the forthcoming analyses on the association between plasma concentrations of POPs and pancreatic cancer risk.

Exposure to persistent organic pollutants: impact on women's health

This literature review focuses on the causal relationship between persistent organic pollutants (POPs) exposure and women's health disorders, particularly cancer, cardio-metabolic events and reproductive health. Progressive industrialization has resulted in the production of a multitude of chemicals that are released into the environment on a daily basis. Environmental chemicals or pollutants are not only hazardous to our ecosystem but also lead to various health problems that affect the human population worldwide irrespective of gender, race or age. However, most environmental health studies that have been conducted, until recently, were exclusively biased with regard to sex and gender, beginning with exposure studies that were reported mostly in male, occupational workers and animal studies being carried out mostly in male rodent models. Health-related issues pertaining to women of all age groups have not been studied thoroughly and rather disregarded in most aspects of basic health science research and it is therefore pertinent that we address these limitations in environmental health. The review also addresses studies looking at the associations between health outcomes and exposures to POPs, particularly, polychlorinated biphenyls (PCBs), dioxins and pesticides, reported in cohort studies while accounting for gender differences. Considering that current levels of POPs in women can also impact future generations, informative guidelines related to dietary patterns and exposure history are needed for women of reproductive age. Additionally, occupational cohorts of highly exposed women worldwide, such as women working in manufacturing plants and female pesticide applicators are required to gather more information on population susceptibility and disease pathology.

Construction of the hydrological condition-persistent organic pollutants relationship in the Yangtze River Estuary

With anthropogenic activities, the persistent organic pollutants (POPs) accumulated in estuary has been notably concern but the influences of complex hydrodynamic conditions on the fate of POPs in estuary have not fully understood. In this study, the bottom velocity and the concentration of suspended sediment in the Yangtze River Estuary (YRE) were determined using the Acoustic Doppler Current Profiler (ADCP), while the concentration of three typical POPs with distinguishing properties, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organichlorine pesticides (OCPs), were determined simultaneously. Then three nonlinear equations were determined for identifying the hotspots of PCBs, OCPs and PAHs in the YRE. The results indicated the goodness-of-fitting of these three equations were satisfactory, indicating the bottom velocity and the suspended sediment level could be used as the reference factor of POPs. For the YRE, the north branch, the upstream of the north branch, and the mouth of the YRE are identified as the hotspots of PCBs, PAHs and OCPs, especially in the normal, flood and dry season, respectively. Simple structure and easy data availability make the results and methods presented in this paper to be easily used as a reference for POPs studies in other regions.

The LIFE PERSUADED project approach on phthalates and bisphenol A biomonitoring in Italian mother-child pairs linking exposure and juvenile diseases

Phthalates and bisphenol A (BPA), plasticizers used in several products of daily life, are considered as endocrine disrupters, therefore children exposure is particularly relevant. The LIFE PERSUADED project aims to define the following: (a) the evaluation of internal levels of DEHP's metabolites and BPA in Italian children and their mothers, (b) the association of the exposure with puberty development and obesity diseases, and (c) the effects of exposure in juvenile in vivo model. The cross-sectional study has involved 2160 mother-child pairs, including males and females, children and adolescents, from urban and rural areas of North, Center, and South Italy. A structured questionnaire and a food diary are designed to evaluate the association between lifestyle variables potentially related to DEHP/BPA exposure and internal levels, through univariate and multivariate analyses. Two pilot case-control studies are carried out on idiopathic premature thelarche and precocious puberty (30 girls each group, aged 2-7 years) and idiopathic obesity (30 boys and 30 girls, aged 6-10 years), matched to healthy controls. BPA and DEHP's metabolites are analyzed in urine samples from all recruited subjects. Clinical and toxicological biomarkers are evaluated in serum of case-control subjects. Moreover, the toxicity study is carried out in a juvenile rodent model exposed to mixtures of BPA and DEHP at dose levels recorded in children population. The scientific results of LIFE PERSUADED will contribute to risk assessment of BPA and DEHP.

Association of serum levels of perfluoroalkyl substances with gestational diabetes mellitus and postpartum blood glucose

This study was conducted to examine the association of perfluoroalkyl substance (PFAS) exposure with gestational diabetes mellitus (GDM) risk and postpartum fasting blood glucose. We used a 1:2 matched case-control study with 84 GDM subjects and 168 healthy pregnant women from Beijing, China. The maternal blood was collected at 1-2days before delivery, and eight linear isomers and fourteen branched isomers were determined in maternal serum. Logistic regression analyses were performed to evaluate the associations after adjusting for potential confounders. The median of the sum of levels of total PFASs was 4.24ng/mL with a interquartile range (IQR) of 2.82-6.54ng/mL. Although maternal PFAS exposure was not associated with risk of GDM, significant positive associations were observed between evaluated exposure to specific PFAS congeners and increasing blood glucose. The odds ratio (ORs) of the highest category of postpartum fasting blood glucose for perfluoro-1-metylheptylsulfonat (1m-PFOS), perfluoro-3/4-metylheptylsulfonat (3m+4m-PFOS), perfluoro-5-metylheptylsulfonat (5m-PFOS), and perfluorohexane sulfonate (PFHxS) were 2.03 (95% CI: 1.09-3.77), 1.93 (95% CI: 1.04-3.58), 2.48 (95% CI: 1.33-4.65), and 2.26 (95% CI: 1.21-4.21), respectively, suggesting negative effects of maternal exposure to specific PFAS compounds on glucose metabolism.

Non-dioxin-like polychlorinated biphenyls in early pregnancy and risk of gestational diabetes mellitus

Several studies support a plausible association of human exposure to polychlorinated biphenyls (PCBs) with type 2 diabetes mellitus. However, little is known about the potential link between circulating PCBs levels in early pregnancy and development of gestational diabetes mellitus (GDM). Here, we conducted a prospective study with a nested case-control design to determine the association of PCB exposure in early pregnancy with GDM risk. Concentrations of selected so-called 'indicator PCBs' were determined in sera of women in the first trimester of pregnancy via gas chromatography - high resolution mass spectrometry. Pregnant women were screened for GDM at 24-28 weeks of gestation using the oral glucose test (OGTT). GDM was defined based on the diagnostic criteria set by China Ministry of Health. Conditional logistic and linear regression models were employed to evaluate the association of PCB exposure with GDM risk and OGTT values, respectively. The odds ratios (OR) of PCB-28, PCB-52, and PCB-101 for GDM were 1.86 (95% CI: 1.05-3.27), 1.90 (95% CI: 1.28-2.82) and 1.85 (95% CI: 1.22-2.82), respectively. No statistical association was evident for other PCBs. However, after adjusting for confounders including some PCB congeners, only PCB-52 remained significantly associated with GDM with OR of 1.97 (95% CI: 1.27-3.07). Moreover, PCB-52 was positively associated with all blood glucose values of OGTT (p < 0.05). Our findings collectively suggest that serum levels of specific non-dioxin-like PCBs in early pregnancy disturb the glucose metabolism and increase the risk of GDM.

Electronic Health Record Driven Prediction for Gestational Diabetes Mellitus in Early Pregnancy

Gestational diabetes mellitus (GDM) is conventionally confirmed with oral glucose tolerance test (OGTT) in 24 to 28 weeks of gestation, but it is still uncertain whether it can be predicted with secondary use of electronic health records (EHRs) in early pregnancy. To this purpose, the cost-sensitive hybrid model (CSHM) and five conventional machine learning methods are used to construct the predictive models, capturing the future risks of GDM in the temporally aggregated EHRs. The experimental data sources from a nested case-control study cohort, containing 33,935 gestational women in West China Second Hospital. After data cleaning, 4,378 cases and 50 attributes are stored and collected for the data set. Through selecting the most feasible method, the cost parameter of CSHM is adapted to deal with imbalance of the dataset. In the experiment, 3940 samples are used for training and the rest 438 samples for testing. Although the accuracy of positive samples is barely acceptable (62.16%), the results suggest that the vast majority (98.4%) of those predicted positive instances are real positives. To our knowledge, this is the first study to apply machine learning models with EHRs to predict GDM, which will facilitate personalized medicine in maternal health management in the future.

Gestational diabetes and offspring birth size at elevated environmental pollutant exposures

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with increased availability of glucose and macronutrients in fetal circulation and macrosomia. Therefore, the role of GDM in the association between metabolism-disrupting chemicals and birth size deserves attention.

OBJECTIVE

We examined whether GDM may mediate or modify the associations between maternal environmental pollutant exposures and offspring birth size measures.

METHODS

We analyzed 604 Faroese pregnant women and their offsprings born in 1997-2000. Maternal pregnancy serum concentrations of organochlorine compounds (OCs: polychlorinated biphenyl (PCB) congeners and dichlorodiphenyldichloroethylene (DDE)), and five perfluoroalkyl substances (PFASs), and hair and cord blood mercury concentrations were measured. We used regression (single-pollutants) and structural equation models (SEMs) (multiple-pollutant analyses using latent constructs of OCs, PFASs and mercury) to estimate the associations with GDM and birth size measures, accounting for mediation and/or effect modification by GDM.

RESULTS

Serum-DDE and hair-mercury concentrations were associated with GDM (adjusted OR per concentration doubling: 1.29; 95% CI: 0.94, 1.77 for DDE, and 0.79; 95% CI: 0.62, 0.99 for mercury), but in multiple pollutant-adjusted SEMs only a positive association between OC exposure and GDM remained significant (change in GDM odds per OC doubling: 0.45; 95% CI: 0.05, 0.86). PCB and overall OC exposure were positively associated with head circumference (SEM; mean change per OC doubling: 0.13cm; 95% CI, 0.01. 0.25). Overall PFAS exposure was inversely associated with birth weight (SEM; mean change per PFAS doubling: -169g; 95% CI: -359, 21), and for many single-PFASs we found a pattern of inverse associations with birth weight and head circumference in boys, and positive or null associations in girls. None of the environmental pollutants was associated with offspring length. GDM neither modified nor mediated the associations with birth size measures.

CONCLUSIONS

We found associations with GDM and offspring birth size to be specific to the environmental pollutant or pollutant group. Associations with birth size measures appear to be independent of GDM occurrence.