Diethylhexyl phthalates is associated with insulin resistance via oxidative stress in the elderly: a panel study

Fish Oil Supplementation with Resistance Exercise Training Enhances Physical Function and Cardiometabolic Health in Postmenopausal Women

Menopause is a condition associated with an increased risk of dysregulation in cardiovascular and metabolic health among older women. While fish oil (FO) has garnered great attention for its health-enhancing properties, its potential for enhancing cardiometabolic health in this demographic remains to be established. The purpose of this study was to determine the clinical efficacy of an 8 wk administration of FO combined with programmed resistance exercise training (RET) on physical function and risk factors associated with cardiometabolic health in healthy older women. Twenty, healthy, older women were randomly assigned to one of the two experimental groups: resistance training with placebo (RET-PL) or RET with fish oil (RET-FO). Physical function, blood pressure (BP), triglyceride (TG), and systemic inflammation and oxidative stress biomarkers were assessed before and after the intervention. Statistical significance was set at p ≤ 0.05. Physical function was greatly enhanced in both RET and RET-FO. Handgrip strength substantially increased only in RET-FO. RET-FO exhibited significant decreases in BP, TG, inflammatory cytokines (TNF-α and IL-6), and oxidative stress (MDA and 8-OHdG) levels, while no detectable changes were found in RET-PL. Our findings indicate that FO administration during 8 wks of RET appears to enhance muscle function and lower risk factors linked to cardiometabolic disorders in postmenopausal women.

Food contaminants and potential risk of diabetes development: A narrative review

The number of people diagnosed with diabetes continues to increase, especially among younger populations. Apart from genetic predisposition and lifestyle, there is increasing scientific and public concern that environmental agents may also contribute to diabetes. Food contamination by chemical substances that originate from packaging materials, or are the result of chemical reactions during food processing, is generally recognized as a worldwide problem with potential health hazards. Phthalates, bisphenol A (BPA) and acrylamide (AA) have been the focus of attention in recent years, due to the numerous adverse health effects associated with their exposure. This paper summarizes the available data about the association between phthalates, BPA and AA exposure and diabetes. Although their mechanism of action has not been fully clarified, in vitro, in vivo and epidemiological studies have made significant progress toward identifying the potential roles of phthalates, BPA and AA in diabetes development and progression. These chemicals interfere with multiple signaling pathways involved in glucose and lipid homeostasis and can aggravate the symptoms of diabetes. Especially concerning are the effects of exposure during early stages and the gestational period. Well-designed prospective studies are needed in order to better establish prevention strategies against the harmful effects of these food contaminants.

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.

Phthalate mixtures and insulin resistance: an item response theory approach to quantify exposure burden to phthalate mixtures

BACKGROUND

Molar sums are often used to quantify total phthalate exposure, but they do not capture patterns of exposure to multiple phthalates.

OBJECTIVE

To introduce an exposure burden score method for quantifying exposure to phthalate metabolites and examine the association between phthalate burden scores and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).

METHODS

We applied item response theory (IRT) to data from 3474 adults aged 20-60 years in the 2013-2018 National Health and Examination Survey (NHANES) to quantify latent phthalate exposure burden from 12 phthalate metabolites. We compared model fits of three IRT models that used different a priori groupings (general phthalate burden; low molecular weight (LMW) and high molecular weight (HMW) burdens; and LMW, HMW and DEHP burden), and used the best fitting model to estimate phthalate exposure burden scores. Regression models assessed the covariate-adjusted association between phthalate burden scores and HOMA-IR. We compared findings to those using molar sums. In secondary analyses, we examined how the IRT model could be used for data harmonization when a subset of participants are missing some phthalate metabolites, and accounted for measurement error of the phthalate burden scores in estimating associations with HOMA-IR through a resampling approach using plausible value imputation.

RESULTS

A three correlated factors model (LMW, HMW and DEHP burdens) provided the best fit. One interquartile range (IQR) increase in DEHP burden score was associated with 0.094 (95% CI: 0.022, 0.164, p = 0.010) increase in log HOMA-IR, co-adjusted for LMW and HMW burden scores. Findings were consistent when using log molar sums. Associations of phthalate burden and insulin resistance were also consistent when participants were simulated to be missing some phthalate metabolites, and when we accounted for measurement error in estimating burden scores.

CONCLUSION

Both phthalate molar sums and burden scores are sensitive to associations with insulin resistance. Phthalate burden scores may be useful for data harmonization.

Occupational differences in personal care product use and urinary concentration of endocrine disrupting chemicals by gender

BACKGROUND

In most societies, women and men systematically differ in consumption of cosmetics and household products, which are interlinked with gendered norms and occupational segregation. We investigated the differences in personal care product (PCP) use and exposure to endocrine disrupting chemicals (EDCs) based on occupation and gender.

METHODS

We utilized data from the first to third Korean National Environmental Health Survey analyzing 9218 participants aged 20-59 years engaged in their current occupation for ≥3 months. Frequent PCP use (≥once/week) and exposure to EDCs were analyzed by gender and occupation. We used least-square geometric means (LSGMs) of urinary concentrations of the five EDCs adjusted for covariates.

RESULTS

Manual occupation was most common in men and no paid occupation was most frequent in women. In general, clerical, service, and sales workers showed the highest prevalence of frequent use of hair and body products. Women used body and makeup products more frequently than men. For all five EDCs, similarly, women showed higher urinary levels in all occupation groups. When stratified by gender, the differences in urinary concentration of EDCs across occupation groups were not observed in men. Among women, clerical, service, and sales workers showed higher bisphenol A (BPA) and mono-n-butyl phthalate (MnBP) levels than manual workers.

CONCLUSIONS

Differentials in exposure to EDCs by occupation groups were not evident for men. Given the higher urinary concentration of EDCs in women compared to men, interventions to reduce the exposure to EDCs would need to focus on women, especially in clerical, service, and sales occupations.

Dibutyl phthalate affects insulin synthesis and secretion by regulating the mitochondrial apoptotic pathway and oxidative stress in rat insulinoma cells

Dibutyl phthalate (DBP) is a typical phthalate (PAEs). The environmental health risks of DBP have gradually attracted attention due to the common use in the production of plastics, cosmetics and skin care products. DBP was associated with diabetes, but its mechanism is not clear. In this study, an in vitro culture system of rat insulinoma (INS-1) cells was established to explore the effect of DBP on insulin synthesis and secretion and the potential mechanisms. INS-1 cells were cultured in RPMI-1640 medium containing 10% fetal bovine serum and treated with 15, 30, 60 and 120 μmol/L of DBP and dimethyl sulfoxide (vehicle, < 0.1%) for 24 h. The contents of insulin in the intracellular fluid and the extracellular fluid of the cells were measured. The results showed that insulin synthesis and secretion in INS-1 cells were significantly decreased in 120 μmol/L DBP group. The apoptosis rate and mitochondrial membrane potential of INS-1 cells were measured by flow cytometry with annexin V-FITC conjugate and PI, and JC-1, respectively. The results showed that DBP caused an increase in the apoptosis rate and a significant decrease in the mitochondrial membrane potential in INS-1 cells in 60 μmol/L and 120 μmol/L DBP group. The results of western blot showed that the expression of Bax/Bcl-2, caspase-3, caspase-9 and Cyt-C were significantly increased. Meanwhile, the level of oxidative stress in INS-1 cells was detected by fluorescent probes DCFH-DA and western blot. With the increase of DBP exposure, the oxidative stress levels (MDA, GSH/GSSG) were increased; and the antioxidant index (SOD) levels were decreased. Our experimental results provide reliable evidence that DBP induced apoptosis and functional impairment in INS-1 cells through the mitochondrial apoptotic pathway and oxidative stress. Therefore, we hypothesized that interference with these two pathways could be considered in the development of preventive protection measures.

Mixed exposure to phenol, parabens, pesticides, and phthalates and insulin resistance in NHANES: A mixture approach

PURPOSE

The effects of environmental chemicals on insulin resistance have attracted extensive attention. Previous studies typically focused on the single chemical effects. This study adopted three different models to analyze the mixed effects of nine common chemicals (one phenol, two parabens, two chlorophenols and four phthalates) on insulin resistance.

METHODS

Urinary concentrations of chemicals were extracted from National Health and Nutrition Examination Survey (NHANES) 2009-2016. Insulin resistance was assessed using homeostatic model assessment (HOMA) and defined as HOMA-IR >2.6. The generalized linear regression (GLM), weighted quantile sum regression (WQS) and Bayesian kernel machine regression models (BKMR) were applied to assess the relationship between chemical mixture and HOMA-IR or insulin resistance.

RESULTS

Of the 2067 participants included, 872 (42.19 %) were identified as insulin resistant. In single-chemical GLM model, di-2-ethylhexyl phthalate (DEHP) had the highest parameter (β/OR, 95 % CIs) of 0.21 (quartile 4, 0.12- 0.29) and 1.95 (quartile 4, 1.39- 2.74). Similar results were observed in the multi-chemical models, with DEHP (quartile 4) showing the positive relationship with HOMA-IR (0.18, 0.08- 0.28) and insulin resistance (1.76, 1.17- 2.64). According to WQS models, the WQS indices were significantly positively correlated with both HOMA-IR (β: 0.07, 95 % CI: 0.03- 0.12) and insulin resistance (OR: 1.25, 95 % CI: 1.03- 1.53). DEHP was the top-weighted chemical positively correlated with both HOMA-IR and insulin resistance. In the BKMR model, the joint effect was also positively correlated with both outcomes. DEHP remained the main contributor to the joint effect, consistent with WQS analysis.

CONCLUSION

Our findings suggested that these chemical mixtures had the positive joint effects on both HOMA-IR and insulin resistance, with DEHP being the potentially predominant driver. The inter-validation of the three models may indicate that reducing the DEHP concentration could improve glucose homeostasis and reduce the risk of insulin resistance. However, further studies are recommended to deepen our findings and elucidate the mechanisms of insulin resistance and chemical mixture.

Integrated toxicity assessment of DEHP and DBP toward aquatic ecosystem based on multiple trophic model assays

To comprehensively understand the toxic risks of phthalates to aquatic ecosystems, we examined the acute toxicity of di-(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) on multiple trophic models, including algae (Chlorella vulgaris), Daphnia magna and fish (Danio rerio, Pseudorasbora parva). Thus, a 15-day zebrafish exposure was conducted to trace the dynamic changes of phthalate-induced toxic effects. Among the four species, D. magna exhibited the strongest sensitivity to both DEHP and DBP, followed by D. rerio and P. parva. C. vulgaris exhibited the lowest sensitivity to phthalates. The sub-chronic zebrafish assay demonstrated that 1000 μg/L DBP induced significant mortality at 15 days post-exposure (dpe), and DEHP exhibited no lethality at the tested concentrations (10-5000 μg/L). Zebrafish hepatic SOD activity and sod transcription levels were inhibited by DBP from 3 dpe, which was accompanied by increased malondialdehyde level, while zebrafish exposed to DEHP exhibited less oxidative damage. Both DEHP and DBP induced time-dependent alterations on Ache activity in zebrafish brains, thus indicating the potential neurotoxicity toward aquatic organisms. Additionally, 1000 μg/L and higher concentration of DBP caused hepatic DNA damage in zebrafish from 7 dpe. These results provide a better understanding of the health risks of phthalate to water environment.

Medical devices as a source of phthalate exposure: a review of current knowledge and alternative solutions

Phthalates are a group of phthalic acid esters used as plasticisers in a large number of products to improve their flexibility, softness, and extensibility. Their wide use in medical devices, however, raises a lot of concern, as they can enter the organism and have toxic effects on human liver, thyroid, kidneys, lungs, reproductive, endocrine, nervous, and respiratory system and are associated with asthma, obesity, autism, and diabetes. The aim of this review is to summarise current knowledge about phthalate migration from medical devices during different medical procedures and possible impact on patient health. It also looks at alternative plasticisers with supposedly lower migration rates and safer profile. Not enough is known about which and how many phthalates make part of medical devices or about the health impacts of alternative plasticisers or their migration rates.

Maternal Serum and Placental Metabolomes in Association with Prenatal Phthalate Exposure and Neurodevelopmental Outcomes in the MARBLES Cohort

Prenatal exposure to phthalates, a family of endocrine-disrupting plasticizers, is associated with disruption of maternal metabolism and impaired neurodevelopment. We investigated associations between prenatal phthalate exposure and alterations of both the maternal third trimester serum metabolome and the placental metabolome at birth, and associations of these with child neurodevelopmental outcomes using data and samples from the Markers of Autism Risk in Babies Learning Early Signs (MARBLES) cohort. The third trimester serum (n = 106) and placental (n = 132) metabolomes were investigated using 1H nuclear magnetic resonance spectroscopy. Children were assessed clinically for autism spectrum disorder (ASD) and cognitive development. Although none of the urinary phthalate metabolite concentrations were associated with maternal serum metabolites after adjustment for covariates, mixture analysis using quantile g-computation revealed alterations in placental metabolites with increasing concentrations of phthalate metabolites that included reduced concentrations of 2-hydoxybutyrate, carnitine, O-acetylcarnitine, glucitol, and N-acetylneuraminate. Child neurodevelopmental outcome was not associated with the third trimester serum metabolome, but it was correlated with the placental metabolome in male children only. Maternal phthalate exposure during pregnancy is associated with differences in the placental metabolome at delivery, and the placental metabolome is associated with neurodevelopmental outcomes in males in a cohort with high familial ASD risk.

Associations between mixtures of urinary phthalate metabolite concentrations and oxidative stress biomarkers among couples undergoing fertility treatment

Phthalate exposure has been associated with adverse reproductive outcomes and oxidative stress is a potential mechanism by which they act. However, few human studies have explored co-exposure confounding or joint effects. Furthermore, most studies examine associations between biomarkers of exposure and oxidative stress from the same urine sample. We investigated single-exposure, co-exposure-adjusted, and joint associations between phthalate metabolites and oxidative stress in the Environment and Reproductive Health (EARTH) study among couples undergoing fertility treatment. We examined cross-sectional associations in both women and men, and longitudinal associations in women. Urine was collected in the follicular phase (women only) and at the time of fertility procedure (women and men), and analyzed for 11 phthalate metabolites. Urine from the time of fertility procedure was analyzed for oxidative stress biomarkers, including free 8-iso-prostaglandin F2α (8-iso-PGF2α), its primary metabolite (2,3-dinor-5,6-dihydro-15-F2t-isoprostane [F2-IsoP-M]), and prostaglandin F2α (PGF2α). Linear mixed effects models were used to estimate single-exposure associations. Bayesian Kernel Machine Regression (BKMR) was used to adjust for co-exposures and to estimate joint effects. Among women, we observed positive associations between all phthalate metabolites and oxidative stress biomarkers in single-exposure models, but there was clear co-exposure confounding. For instance, in a single-exposure model, we estimated a 63% (95% confidence interval: 51, 77) increase in the 8-iso-PGF2α metabolite per interquartile range (IQR) difference in mono-n-butyl phthalate (MBP) versus a 34% (95% credible interval: 12, 60) increase in co-adjusted models. However, several phthalate metabolites remained associated with oxidative stress in co-exposure models, and the joint effects of all exposures were high (e.g., an 114% increase in the 8-iso-PGF2α metabolite per IQR difference in all exposures). Longitudinal results were also attenuated compared to cross-sectional results in women; however, the joint effect of all exposures and the 8-iso-PGF2α metabolite remained positive and statistically significant (11% increase per IQR difference in all exposures, 95% credible interval: 0.2, 23). In men, associations were generally less pronounced, although the joint effect of the mixture on 8-iso-PGF2α was above the null. Because oxidative stress is related to reproductive success among couples seeking fertility treatment, mitigating phthalate exposure should be considered as a potentially beneficial measure.

Relationships among phthalate exposure, oxidative stress, and insulin resistance in young military soldiers: A cumulative risk assessment and mediation approach

BACKGROUND

Epidemiological studies concerning whether oxidative stress mediates phthalate exposure-insulin resistance (IR) associations in young adults are limited. Therefore, we investigated this potential mediation by using a cumulative risk approach involving daily intake (DI) and a hazard index (HI_RfD).

METHODS

The participants were 391 Taiwanese military personnel. This study measured their IR (as homeostatic model assessment of estimated IR [HOMA-IR]), levels of oxidative stress biomarkers (8-hydroxy-2-deoxyguanosine, 8-nitroguanine, 8-iso-prostaglandin F2α, and N-acetyl-S-[tetrahydro-5-hydroxy-2-pentyl-3-furanyl]-L-cysteine [HNE-MA]), the sum of these four biomarkers (ΣOS), and urinary phthalate metabolite concentrations. The HI_RfD was estimated on the basis of urinary levels of phthalate metabolite, and the DI of five phthalates was determined: dimethyl phthalate, benzyl butyl phthalate (BBzP), diethyl phthalate, dibutyl phthalate (DBP), and di (2-ethylhexyl) phthalate (DEHP). Logistic regression models were employed to explore associations among DI, HI_RfD, oxidative stress biomarkers, and HOMA-IR values. The role played by oxidative stress in the phthalate exposure-HOMA-IR association was determined using mediation analysis.

RESULTS

We discovered positive associations between high DI of DBP, BBzP, and DEHP; high HI_RfD; and high ΣOS. High ΣOS and HNE-MA were associated with a higher likelihood of a high HOMA-IR value. Mediation analysis indicated that high ΣOS and HNE-MA were significant mediators of the associations between phthalates and IR.

CONCLUSION

Oxidative stress may partially mediate the phthalate-IR relationship in young adults.

Acrylamide and Potential Risk of Diabetes Mellitus: Effects on Human Population, Glucose Metabolism and Beta-Cell Toxicity

Diabetes mellitus is a frequent endocrine disorder characterized by hyperglycemia. Acrylamide (AA) is food contaminant formed during the high-temperature processing of food rich in carbohydrates and low in proteins. Recent human epidemiological studies have shown a potential association between AA exposure and the prevalence of diabetes in the general population. In male rats, AA treatment promoted pancreatic islet remodeling, which was determined by alpha-cell expansion and beta-cell reduction, while in female rats AA caused hyperglycemia and histopathological changes in pancreatic islets. In vitro and in vivo rodent model systems have revealed that AA induces oxidative stress in beta cells and that AA impairs glucose metabolism and the insulin signaling pathway. Animal studies have shown that diabetic rodents are more sensitive to acrylamide and that AA aggravates the diabetic state. In this review, we provide an overview of human epidemiological studies that examined the relation between AA exposure and glucose disorders. In addition, the effects of AA treatment on pancreatic islet structure, beta-cell function and glucose metabolism in animal models are comprehensively analyzed with an emphasis on sex-related responses. Furthermore, oxidative stress as a putative mechanism of AA-induced toxicity in beta cells is explored. Finally, we discuss the effects of AA on diabetics in a rodent model system.

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.

Short-term exposure to acrylamide exacerbated metabolic disorders and increased metabolic toxicity susceptibility on adult male mice with diabetes

Diabetes mellitus is a common endocrine metabolic disorder, and previous studies have shown that diabetics are more sensitive to the toxic environmental contaminants. Acrylamide (ACR) is both an industrially multipurpose compound and a common endogenous food contaminant to which people are frequently exposed and at high risk. However, the toxicity of ACR on diabetes hasn't attracted much attention. In this study, both healthy mice and diabetic mice received ACR administration orally to investigate the ACR-induced metabolic toxicity, mechanism and susceptibility to ACR toxicity in adult diabetic male mice. The results showed that ACR significantly increased FBG level and decreased bodyweight, serum lipid and liver lipid biomarkers (TC, TG, LDL-C, HDL-C) levels as well as expression of lipid and glucose metabolism-related genes in diabetic mice, indicating that ACR can exacerbate metabolic disorders of glucose and lipid in diabetic male mice. Moreover, ACR exposure significantly increased levels of MDA and COX-2), decreased GSH level and antioxidant enzyme activity (SOD, GSH-PX and CAT) by downregulating expression of Nrf2 and Keap1 in diabetic mice. Factorial analysis showed ACR had a more significant disturbance in diabetic mice compared with healthy mice. Our results indicated that ACR exposure can cause oxidative stress and inflammatory damage, which can exacerbate abnormal glucose and lipid metabolism. This work helps to elucidate the effects and underlying mechanisms of ACR-induced metabolic toxicity in adults with diabetes.

Role of epidemiology in risk assessment: a case study of five ortho-phthalates

BACKGROUND

The association between environmental chemical exposures and chronic diseases is of increasing concern. Chemical risk assessment relies heavily on pre-market toxicity testing to identify safe levels of exposure, often known as reference doses (RfD), expected to be protective of human health. Although some RfDs have been reassessed in light of new hazard information, it is not a common practice. Continuous surveillance of animal and human data, both in terms of exposures and associated health outcomes, could provide valuable information to risk assessors and regulators. Using ortho-phthalates as case study, we asked whether RfDs deduced from male reproductive toxicity studies and set by traditional regulatory toxicology approaches sufficiently protect the population for other health outcomes.

METHODS

We searched for epidemiological studies on benzyl butyl phthalate (BBP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), dicyclohexyl phthalate (DCHP), and bis(2-ethylhexyl) phthalate (DEHP). Data were extracted from studies where any of the five chemicals or their metabolites were measured and showed a statistically significant association with a health outcome; 38 studies met the criteria. We estimated intake for each phthalate from urinary metabolite concentration and compared estimated intake ranges associated with health endpoints to each phthalate's RfD.

RESULT

For DBP, DIBP, and BBP, the estimated intake ranges significantly associated with health endpoints were all below their individual RfDs. For DEHP, the intake range included associations at levels both below and above its RfD. For DCHP, no relevant studies could be identified. The significantly affected endpoints revealed by our analysis include metabolic, neurodevelopmental and behavioral disorders, obesity, and changes in hormone levels. Most of these conditions are not routinely evaluated in animal testing employed in regulatory toxicology.

CONCLUSION

We conclude that for DBP, DIBP, BBP, and DEHP current RfDs estimated based on male reproductive toxicity may not be sufficiently protective of other health effects. Thus, a new approach is needed where post-market exposures, epidemiological and clinical data are systematically reviewed to ensure adequate health protection.

Exploring personal chemical exposures in China with wearable air pollutant monitors: A repeated-measure study in healthy older adults in Jinan, China

The health impact of airborne contaminants has been challenging to assess due to current limitations in measurement technologies. The emergence of wearable passive samplers coupled with high resolution mass spectrometry (HR-MS) chemical analysis has enabled comprehensive characterization of personal exposures. We conducted a repeated-measure study among 84 older adults in Jinan, China, as part of the Biomarkers for Air Pollutants Exposure (China BAPE) study. Study objectives were: 1) to characterize the occurrence, magnitude, and distribution of personal exposure to airborne contaminants; 2) to evaluate the temporal variation of chemical exposures across the study population; and 3) to identify behavioral and environmental factors that influence the observed variance in chemical exposures. The FreshAir wristband was worn by participants for three consecutive days each month from September 2018 to January 2019 and collected with paired time-activity logs. Passive air samplers were also deployed in parallel at a local outdoor air monitoring station. Spearman's Rho trend test and trajectory cluster analysis were used to identify exposure trends and variation patterns, respectively. Out of the 70 airborne compounds of potential concern screened, 26 compounds from 10 chemical classes were found to be above detection thresholds across >70% of the study population. Personal exposures were predominantly characterized by nine polycyclic aromatic hydrocarbons (PAHs), four phthalates, three nitroaromatics, and two volatile organic compounds (VOCs). Phthalate personal exposures were positively correlated with outdoor temperatures while the inverse relationship was observed for certain PAHs (p < 0.05). Specifically, dimethyl phthalate (r_s = 0.31) decreased as temperatures declined, while nitrobenzene (r_s = -0.35) and naphthalene (r_s = -0.40) increased as temperatures decreased. Compared to levels measured at the outdoor air monitoring site, personal exposure of phthalates was elevated (p < 0.05) and hexachlorobutadiene was lower across participants (p < 0.01). Personal exposure of these chemicals was further found to be weakly associated with daily duration participants spent outdoors. Individuals formed distinct clusters based on trajectories of chemical exposures across the sampling period (September to January), potentially suggestive of distinct emission sources. In conclusion, we demonstrate the feasibility of characterizing the occurrence and magnitude of personal exposure to airborne chemical contaminants using passive wristband samplers. The temporal variability of these personal exposure profiles was highlighted and with distinct trends identified across different groups of individuals. Future studies will integrate this data with other omics datasets collected from this population of Chinese older adults to investigate associations between exposure profiles and health relevant biomarkers, to provide evidence in feasibility of disease prevention through environmental improvements.

The associations of phthalate biomarkers during pregnancy with later glycemia and lipid profiles

BACKGROUND

Pregnancy induces numerous cardiovascular and metabolic changes. Alterations in these sensitive processes may precipitate long-term post-delivery health consequences. Studies have reported associations between phthalates and metabolic complications of pregnancy, but no study has investigated metabolic outcomes beyond pregnancy.

OBJECTIVES

To examine associations of exposure to phthalates during pregnancy with post-delivery metabolic health.

DESIGN

We quantified 15 urinary phthalate biomarker concentrations during the second and third trimesters among 618 pregnant women from Mexico City. Maternal metabolic health biomarkers included fasting blood measures of glycemia [glucose, insulin, Homeostatic Model Assessment of Insulin Resistance [HOMA-IR], % hemoglobin A1c (HbA1c%)] and lipids (total, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, triglycerides), at 4-5 and 6-8 years post-delivery. To estimate the influence of the phthalates mixture, we used Bayesian weighted quantile sum regression and Bayesian kernel machine regression; for individual biomarkers, we used linear mixed models.

RESULTS

As a mixture, higher urinary phthalate biomarker concentrations during pregnancy were associated with post-delivery concentrations of plasma glucose (interquartile range [IQR] difference: 0.13 SD, 95%CrI: 0.05, 0.20), plasma insulin (IQR difference: 0.06 SD, 95%CrI: -0.02, 0.14), HOMA-IR (IQR difference: 0.08 SD, 95% CrI: 0.01, 0.16), and HbA1c% (IQR difference: 0.15 SD, 95%CrI: 0.05, 0.24). Associations were primarily driven by mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) and the sum of dibutyl phthalate biomarkers (∑DBP). The phthalates mixture was associated with lower HDL (IQR difference: -0.08 SD, 95%CrI: -0.16, -0.01), driven by ∑DBP and monoethyl phthalate (MEP), and higher triglyceride levels (IQR difference: 0.15 SD, 95%CrI: 0.08, 0.22), driven by MECPTP and MEP. The overall mixture was not associated with total cholesterol and LDL. However, ∑DBP and MEP were associated with lower and higher total cholesterol, respectively, and MECPTP and ∑DBP were associated with lower LDL.

CONCLUSIONS

Phthalate exposure during pregnancy is associated with adverse long-term changes in maternal metabolic health. A better understanding of timing of the exact biological changes and their implications on metabolic disease risk is needed.

Association between phthalate exposure and insulin resistance: a systematic review and meta-analysis update

An update on systematic review and meta-analysis was performed to explore effects of phthalate exposure on insulin resistance. A systematic literature search was performed in MEDLINE, Web of Science, and CNKI until March 2021. A conceptual framework was constructed to guide the organization and presentation of results. Besides, beta coefficients with corresponding confidence intervals were extracted from the most adjusted models. Extracted beta coefficients were transformed into correlation, and z Fisher transformation of correlation with the corresponding standard error was included in meta-analysis. Subgroup analyses were performed by age (adult vs. adolescent) and sex (female vs. male) of participants and site of study (America and Europe vs. Asia) to explore potential sources of heterogeneity. Nineteen literatures with 12,533 participants reporting on the association of exposure to specific phthalates and insulin resistance were selected. The majority of included studies revealed positive relationships of insulin resistance with different phthalate metabolites exposure. Meta-analyses were performed on 16 studies. Exposure to MnBP, MBzP, MCPP, MEHP, MEOHP, MEHHP, ∑DEHP, and high-molecular weight phthalate (∑HMWP) was associated with the increase of the homeostasis model assessment of insulin resistance (HOMA-IR) index. The results of sensitivity analyses stratified by age, sex, and site of study remained stable, suggesting the robustness of these meta-analyses. Most of heterogeneity in sensitivity analyses decreased to moderate or low degree. Exposure to MnBP, MBzP, MCPP, MEHP, MEOHP, MEHHP, ∑DEHP, and ∑HMWP was associated with the increased risk of HOMA-IR. Age, sex, and site of study might provide limited source of heterogeneity.

The effects of phthalate ester exposure on human health: A review

Phthalate esters (PAEs) are one of the most widely used plasticizers in polymer products and humans are increasingly exposed to them. The constant exposure to PAEs-contained products has raised some concerns against human health. Thus, the impacts of PAEs and their metabolites on human health require a comprehensive study for a better understanding of the associated risks. Here, we attempt to review eight main health effects of PAE exposure according to the most up-to-date studies. We found that epidemiological studies demonstrated a consistent association between PAE exposure (especially DEHP and its metabolites) and a decrease in sperm quality in males and symptom development of ADHD in children. Overall, we found insufficient evidence and lack of consistency of the association between PAE exposure and cardiovascular diseases (hypertension, atherosclerosis, and CHD), thyroid diseases, respiratory diseases, diabetes, obesity, kidney diseases, intelligence performance in children, and other reproductive system-related diseases (anogenital distance, girl precocious puberty, and endometriosis). Future studies (longitudinal and follow-up investigations) need to thoroughly perform in large-scale populations to yield more consistent and powerful results and increase the precision of the association as well as enhance the overall understanding of potential human health risks of PAEs in long-term exposure.

Relationship of Urinary Phthalate Metabolites with Cardiometabolic Risk Factors and Oxidative Stress Markers in Children and Adolescents

Introduction

Studies have proved that exposure of adults to phthalates might be related to cardiometabolic risk factors and changes in markers of oxidative stress. Such studies conducted on school-age children and adolescents are limited and fail to assess the simultaneous effect of phthalates on these risk factors and oxidative stress markers. Therefore, it was attempted to identify the relationship of urinary phthalate metabolites with cardiometabolic risk factors and oxidative stress markers in children and adolescents. Methods. In this cross-sectional study, 108 children and adolescents, living in Isfahan industrial city of Iran, were examined. Urine samples taken from the participants were analyzed for mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-exohexyl) phthalate (MEOHP), and mono-methyl phthalate (MMP).

Results

Results showed that, among phthalate metabolites, MBP had the highest concentration, followed by MBzP, MEOHP, MEHHP, MEHP, and MMP. Concentrations of these metabolites had a significant relationship with some of the cardiometabolic risk factors including systolic blood pressure (SBP), fasting blood sugar (FBS), and triglycerides (TG) (p < 0.05). Furthermore, the crude and adjusted linear regression models indicated the significant association of phthalate metabolites with superoxide dismutase (SOD), malondialdehyde (MDA), and homeostasis model assessment of insulin resistance (HOMA-IR) (p < 0.05).

Conclusion

Although urinary phthalate concentrations could not exactly reflect the long-term exposure level in the studied age groups, the consumption of phthalate-free products during childhood and adolescent development shall be assumed helpful in maintaining a healthy lifestyle. To confirm these findings and develop effective intervention strategies, it would be necessary to perform longitudinal studies on diverse population.

GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air

A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m³, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2-5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a 'reference city' for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.

Intrauterine exposure to low-dose DBP in the mice induces obesity in offspring via suppression of UCP1 mediated ER stress

Dibutyl phthalate (DBP) is recognized as an environmental endocrine disruptor that has been detected in fetal and postnatal samples. Recent evidence found that in utero DBP exposure was associated with an increase of adipose tissue weight and serum lipids in offspring, but the precise mechanism is unknown. Here we aimed to study the effects of in utero DBP exposure on obesity in offspring and examine possible mechanisms. SPF C57BL/6J pregnant mice were gavaged with either DBP (5 mg /kg/day) or corn oil, from gestational day 12 until postnatal day 7. After the offspring were weaned, the mice were fed a standard diet for 21 weeks, and in the last 2 weeks 20 mice were selected for TUDCA treatment. Intrauterine exposure to low-dose DBP promoted obesity in offspring, with evidence of glucose and lipid metabolic disorders and a decreased metabolic rate. Compared to controls, the DBP exposed mice had lower expression of UCP1 and significantly higher expression of Bip and Chop, known markers of endoplasmic reticulum (ER) stress. However, TUDCA treatment of DBP exposed mice returned these parameters nearly to the levels of the controls, with increased expression of UCP1, lower expression of Bip and Chop and ameliorated obesity. Intrauterine exposure of mice to low-dose DBP appears to promote obesity in offspring by inhibiting UCP1 via ER stress, a process that was largely reversed by treatment with TUDCA.

Critical Review on the Presence of Phthalates in Food and Evidence of Their Biological Impact

Phthalates are a huge class of chemicals with a wide spectrum of industrial uses, from the manufacture of plastics to food contact applications, children's toys, and medical devices. People and animals can be exposed through different routes (i.e., ingestion, inhalation, dermal, or iatrogenic exposure), as these compounds can be easily released from plastics to water, food, soil, air, making them ubiquitous environmental contaminants. In the last decades, phthalates and their metabolites have proven to be of concern, particularly in products for pregnant women or children. Moreover, many authors reported high concentrations of phthalates in soft drinks, mineral waters, wine, oil, ready-to-eat meals, and other products, as a possible consequence of their accumulation along the food production chain and their accidental release from packaging materials. However, due to their different physical and chemical properties, phthalates do not have the same human and environmental impacts and their association to several human diseases is still under debate. In this review we provide an overview of phthalate toxicity, pointing out the health and legal issues related to their occurrence in several types of food and beverage.

Epigenetic repression of miR-17 contributed to di(2-ethylhexyl) phthalate-triggered insulin resistance by targeting Keap1-Nrf2/miR-200a axis in skeletal muscle

Rationale: Skeletal muscle insulin resistance is detectable before type 2 diabetes is diagnosed. Exposure to di(2-ethylhexyl) phthalate (DEHP), a typical environmental endocrine-disrupting chemical, is a novel risk factor for insulin resistance and type 2 diabetes. This study aimed to explore insulin signaling regulatory pathway in skeletal muscle of the DEHP-induced insulin-resistant mice and to investigate potential therapeutic strategies for treating insulin resistance.

Methods: C57BL/6J male mice were exposed to 2 mg/kg/day DEHP for 15 weeks. Whole-body glucose homeostasis, oxidative stress and deregulated miRNA-mediated molecular transduction in skeletal muscle were examined. microRNA (miRNA) interventions based on lentiviruses and adeno-associated viruses 9 (AAV9) were performed.

Results: Dnmt3a-dependent promoter methylation and lncRNA Malat1-related sponge functions cooperatively downregulated miR-17 in DEHP-exposed skeletal muscle cells. DEHP suppressed miR-17 to disrupt the Keap1-Nrf2 redox system and to activate oxidative stress-responsive Txnip in skeletal muscle. Oxidative stress upregulated miR-200a, which directly targets the 3'UTR of Insr and Irs1, leading to hindered insulin signaling and impaired insulin-dependent glucose uptake in skeletal muscle, ultimately promoting the development of insulin resistance. AAV9-induced overexpression of miR-17 and lentivirus-mediated silencing of miR-200a in skeletal muscle ameliorated whole-body insulin resistance in DEHP-exposed mice.

Conclusions: The miR-17/Keap1-Nrf2/miR-200a axis contributed to DEHP-induced insulin resistance. miR-17 is a positive regulator, whereas miR-200a is a negative regulator of insulin signaling in skeletal muscle, and both miRNAs have the potential to become therapeutic targets for preventing and treating insulin resistance or type 2 diabetes.

Phthalates Implications in the Cardiovascular System

Today’s sedentary lifestyle and eating habits have been implicated as some of the causes of the increased incidence of several diseases, including cancer and cardiovascular diseases. However, environmental pollutants have also been identified as another possible cause for this increase in recent decades. The constant human exposure to plastics has been raising attention regarding human health, particularly when it comes to phthalates. These are plasticizers used in the manufacture of industrial and consumer products, such as PVC (Polyvinyl Chloride) plastics and personal care products, with endocrine-disrupting properties, as they can bind molecular targets in the body and interfere with hormonal function. Since these compounds are not covalently bound to the plastic, they are easily released into the environment during their manufacture, use, or disposal, leading to increased human exposure and enhancing health risks. In fact, some studies have related phthalate exposure with cardiovascular health, having already shown a positive association with the development of hypertension and atherosclerosis in adults and some cardiometabolic risk factors in children and adolescents. Therefore, the main purpose of this review is to present and relate the most recent studies concerning the implications of phthalates effects on the cardiovascular system.

Mediating role of oxidative/nitrosative stress biomarkers in the associations between phthalate exposure and thyroid function in Taiwanese adults

Phthalate exposure was shown to alter thyroid function, however it is unclear, whether oxidative and nitrosative stress explains the intermediate biological mechanism. This study aimed to investigate the associations between phthalate exposure, oxidative/nitrosative stress, and thyroid function in adults, and to examine the mediating role of oxidative/nitrosative stress in the associations between phthalate exposure and thyroid function. Levels of eleven urinary phthalate metabolites, three urinary biomarkers of oxidative/nitrosative stress (malondialdehyde [MDA], 8-OHdG, and 8-NO₂Gua) and five serum thyroid hormones (thyroxine [T₄], free T₄, triiodothyronine, thyroid-stimulating hormone, and thyroxine-binding globulin) were measured in 266 Taiwanese adults. Cross-sectional associations between phthalate metabolites, biomarkers of oxidative/ nitrosative stress and thyroid hormones were analyzed using multivariate regression models. Mediation analysis was conducted to assess the role of oxidative/nitrosative stress in the associations between phthalate metabolites and thyroid hormone levels. Sum of di-(2-ethylhexyl) phthalate (DEHP) metabolites was positively associated with MDA (β_T1-T2 = 0.253, 95%CI [0.060, 0.447]; β _{≧ T2} = 0.317, 95% CI [0.098, 0.536]; P_trend = 0.005) and 8-NO₂Gua (β_T1-T2 = -0.010, 95%CI [-0.138, 0.118]; β _{≧ T2} = 0.144, 95% CI [-0.001, 0.289]; P_trend = 0.045). Mono-n-butyl phthalate (MnBP) was positively associated with 8-NO₂Gua (β_T1-T2 = 0.201, 95% CI [0.078, -0.324]; β _{≧ T2} = 0.161, 95% CI [0.031, -0.292]; P_trend = 0.018). T₄ was negatively associated with MDA (β_T1-T2 =  -0.027, 95% CI [-0.088, 0.0034]; β_≧T2 = -0.094, 95% CI [-0.161, -0.028]; P_trend = 0.005) and 8-NO₂Gua (β_T1-T2 = -0.068, 95% CI [-0.127, -0.010]; β_≧T2 = -0.125, 95% CI [-0.184, -0.066]; P_trend < 0.001). Free T₄ was positively associated with MDA (P_trend = 0.047) and with 8-NO₂Gua (P_trend < 0.001). 8-NO₂Gua mediated 11% of the association between the sum of DEHP metabolites and T₄, and 17% of the association between MnBP and free T₄. These results suggest that phthalate exposure may influence thyroid hormone levels through induced oxidative/nitrosative stress.

The Impact of Di-2-Ethylhexyl Phthalate on Sperm Fertility

A growing number of studies point to reduced fertility upon chronic exposure to endocrine-disrupting chemicals (EDCs) such as phthalates and plasticizers. These toxins are ubiquitous and are often found in food and beverage containers, medical devices, as well as in common household and personal care items. Animal studies with EDCs, such as phthalates and bisphenol A have shown a dose-dependent decrease in fertility and embryo toxicity upon chronic exposure. However, limited research has been conducted on the acute effects of these EDCs on male fertility. Here we used a murine model to test the acute effects of four ubiquitous environmental toxins: bisphenol A (BPA), di-2-ethylhexyl phthalate (DEHP), diethyl phthalate (DEP), and dimethyl phthalate (DMP) on sperm fertilizing ability and pre-implantation embryo development. The most potent of these toxins, di-2-ethylhexyl phthalate (DEHP), was further evaluated for its effect on sperm ion channel activity, capacitation status, acrosome reaction and generation of reactive oxygen species (ROS). DEHP demonstrated a profound hazardous effect on sperm fertility by producing an altered capacitation profile, impairing the acrosome reaction, and, interestingly, also increasing ROS production. These results indicate that in addition to its known chronic impact on reproductive potential, DEHP also imposes acute and profound damage to spermatozoa, and thus, represents a significant risk to male fertility.

Long-term dietary administration of diethyl phthalate triggers loss of insulin sensitivity in two key insulin target tissues of mice

Over the past years, a growing body of work has linked numerous pervasive environmental chemicals with a multitude of adverse reproductive, developmental, behavioral, and metabolic changes in humans and animal models. Plasticizers include a wide variety of phthalate esters that are extensively used in a host of personal day care and cosmetic products. Many population-based studies have indicated a close association between diethyl phthalate (DEP) and diabetes albeit the mechanisms remain much unexplored. Presently, we report that long-term dietary administration of DEP to adult male Swiss albino mice at two different concentrations mirroring the recommended tolerable doses, severely impaired insulin signaling in hepatocytes and adipocytes. This was concomitant with sustained oxidative stress from the overactivation of NADPH oxidase 2, a major intracellular source of reactive oxygen species, in both the cell types. The present study provides evidences of the onset of insulin resistance in mice after chronic exposure to DEP in diet even at lower levels. This, in turn, can have serious pathological consequences with ultimate manifestations of type 2 diabetes and metabolic syndrome (MetS). Thus, by disrupting the central metabolic function of liver and adipose tissue, the key insulin target tissues, daily exposure to phthalates in plastics can potentially contribute to the alarming prevalence of MetS in recent times.

Di-(2-ethylhexyl) Phthalate (DEHP) and Uterine Histological Characteristics

Phthalates have a long industrial history. It is suspected that phthalates and their metabolites have detrimental effects on reproduction and development. They are well-known for their anti-androgenic effects. Several studies have indicated that phthalates and their metabolites are reprotoxic in males and endocrine disruptors. Reproduction and embryogenesis occur in the uterus of female eutherian mammals. A horizontal analytical method is preferred to elucidate the toxic effects of phthalates on human reproduction. Nevertheless, there are vast numbers of known phthalates and not all of their modes of action have been clarified. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer and has been the subject of numerous toxicological studies. However, few of these have reported on the toxic effects of DEHP, its metabolites, other phthalates, or mixtures on female reproduction. Acute and high doses of DEHP adversely affect uterine histology. Recently, it was disclosed that chronic exposures to low doses of DEHP have endocrine disruption efficacy. DEHP induces various cellular responses including modulation of the expression and regulation of steroid hormone receptors and transcription and paracrine factors. Uteri do not respond uniformly to DEHP exposure. The phenotypic manifestations and effects on fertility in response to DEHP and its metabolites may vary with species, developmental stage, and generation. Hence, DEHP exposure may histological alter the uterus and induce endometriosis, endometriosis, hyperplasia, myoma, and developmental and reproductive toxicity.

Diabetes and Toxicant Exposure

The worldwide prevalence of obesity has near tripled between 1975 and 2016. Diabetes was the direct cause of an estimated 1.6 million deaths in 2015. Diabetogens, otherwise known as toxicants that cause insulin resistance in animal models and humans as a result of pancreatic β-cell damage include the persistent organochlorine pesticides trans-nonachlor, oxychlordane, and DDE -the main metabolite of DDT, as well as another class of persistent organic pollutants, polychlorinated biphenyls (PCBs). Other toxicants that are now considered diabetogens: BPA, arsenic, phthalates, perfluorinates (PFOS), diethyl hexyl phthalate (DEHP), and dioxin (TCDD) are commonly found in the blood and urine in the CDC NHANES populations and presumed to also be commonly found in the U.S. population as a whole. A review of the literature on the risk for diabetes in epidemiologic studies considering these toxicants, challenges for clinicians using lab testing for these diabetogens, and the necessary interventions for lowering body burden of persistent toxicants are discussed.

The endocrine disruptor DEHP and the ECS: analysis of a possible crosstalk

Studies of the last decade associated the environmental contamination by di-(2-ethylhexyl)-phthalate (DEHP) with obesity and endocrine malfunction. DEHP was found to interact with several receptors - among them are receptors of the endocannabinoid system (ECS) with high expression levels in adipose tissue. Furthermore, the correlation for BMI and body fat to the serum endocannabinoid level raises the question if the obesogenic and endocrine-disrupting DEHP effects are mediated via the ECS. We therefore characterized the ECS in a human cell model of adipogenesis using the SGBS preadipocytes to subsequently investigate if DEHP exposure affects the intrinsic ECS. The receptors of the ECS and the endocannabinoid-metabolizing enzymes were upregulated during normal adipogenesis, accompanied by an increasing secretion of the adipokines adiponectin and leptin. DEHP affected the secretion of both adipokines but not the ECS, suggesting DEHP to alter the endocrine function of adipocytes without the involvement of the intrinsic ECS.

Could phthalates exposure contribute to the development of metabolic syndrome and liver disease in humans?

In the study, 305 patients of both genders were enrolled and divided into three groups: obese (BMI > 30 kg/m²), patients who were diagnosed type 2 diabetes mellitus (T2DM), and control, normal weight healthy volunteers. At least one of ten different phthalate metabolites was determined in the urine samples of 49.84% all enrolled participants. In the obese subgroup, the sum of all urinary phthalate metabolites was positively associated with TG levels (p = 0.031) together with derived TC/HDL and TG/HDL ratios (p = 0.023 and 0.015), respectively. Urinary MEP concentration was positively correlated with the HOMA-IR in T2DM subgroup (p = 0.016) while in the control subgroup, log₁₀MEP levels were negatively correlated with total cholesterol (p = 0.0051), and LDL serum levels (p = 0.0015), respectively. Also, in the control subgroup, positive linear correlations between urinary log₁₀MEP levels and TyG and TYG-BMI values (p = 0.028 and p = 0.027), respectively, were determined. Urinary MEHP levels were associated with glucose serum levels (p = 0.02) in T2DM subgroup, while in the control HDL values were negatively associated with log₁₀MEHP (p = 0.0035). Healthy volunteers exposed to phthalates had elevated AST levels in comparison to non-exposed ones (p = 0.023). In control subgroup, ALT and AST values were increased (p = 0.02 and p = 0.01, respectively) in MEP exposed while GGT levels were enhanced (p = 0.017) in MEHP exposed in comparison with non-exposed. Combined phthalates influence on glucose and lipid metabolism may increase the possibility for NAFLD and insulin resistance development among exposed individuals.

Antidiabetic Activity of Gold Nanoparticles Synthesized Using Wedelolactone in RIN-5F Cell Line

We synthesized the gold nanoparticles (AuNPs) using wedelolactone (WDL) and characterized them using UV-visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopic (TEM), energy dispersive X-ray diffraction, and atomic force microscopic (AFM) studies. The electronic spectrum exhibited an absorption peak at 535 nm. The FT-IR results proved that WDL was stabilized on the surface of AuNPs by acting as a capping or reducing agent. The crystalline structure was affirmed by XRD pattern and the spherical shape of WDL-AuNPs was evidenced by SEM, TEM, and AFM. The synthesized WDL-AuNPS were evaluated for anti-diabetic activity in pancreatic RIN-5F cell lines. In vitro results showed that WDL-AuNPs did not only improve the insulin secretion affected by di-(2-ethylhexyl) phthalate (DEHP), but also the cell viability in RIN5F cells. WDL-AuNPs treatment modulates the pro-apoptotic proteins and anti-apoptotic proteins expression to prevent the cells undergoing apoptosis in DEHP-exposed RIN-5F cells. The exposure of DEHP causes an increase in ROS production and lipid peroxidation levels. The free radical scavenging and antioxidant properties of WDL-AuNPs increase the deleterious effect caused by DEHP. On the other side, WDL-AuNPs increase mRNA expressions of insulin-signaling proteins in RIN-5F cells. This study concludes that WDL-AuNPs can be successfully used to regulate the expression of Bcl-2 family proteins, reduce lipid peroxidation, and to improve the secretion of antioxidants and insulin through the GLUT2 pathway in RIN-5F cell lines.

Serum beta-carotene modifies the association between phthalate mixtures and insulin resistance: The National Health and Nutrition Examination Survey 2003-2006

Animal models suggest a protective role of antioxidants against the adverse effect of di-2-ethylhexyl phthalate (DEHP) on insulin resistance. However, no epidemiologic study has examined the effects observed in the animal model. We conduct a study to examine associations of urinary concentrations of phthalate metabolites (individually and as a mixture) with insulin resistance, along with potential effect modification by serum antioxidant concentrations. This cross-sectional study included 1605 participants (51% males) aged 12-85 from the National Health and Nutrition Examination Surveys (2003-2006). Urinary concentrations of 9 phthalate metabolites were measured from spot urine samples. Antioxidant (vitamin A, C, E, and carotenoids) concentrations were measured from a fasting serum sample. We used Bayesian Kernel Machine Regression (BKMR) to evaluate associations between phthalate metabolite mixtures and insulin resistance, and examined whether serum antioxidant levels modified these associations, while accounting for the correlations of multiple concurrent exposures. A change in urinary ΣDEHP concentrations from the 25th to the 75th percentile was associated with a higher log HOMA-IR of 0.07 (95% CI = 0.01, 0.14) (4.85% increase in HOMA-IR). In contrast, the same change in urinary monoethyl phthalate (MEP) was associated with a lower HOMA-IR of -0.07 (95% CI = -0.14, -0.02) (6.68% decrease in HOMA-IR). The positive association between ΣDEHP and HOMA-IR became weaker at higher concentrations of serum β-carotene. The relationship between MEP and HOMA-IR, however, was not modified by the serum antioxidants examined. The remaining phthalate metabolites were unrelated to HOMA-IR. In this cross-sectional study, the positive association between DEHP exposure and insulin resistance weakened among participants with higher concentrations of serum β-carotene. As this is the first human report on the protective role of serum β-carotene on DEHP induced insulin resistance, future studies are needed.

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.

Early life exposure to di(2-ethylhexyl)phthalate causes age-related declines associated with insulin/IGF-1-like signaling pathway and SKN-1 in Caenorhabditis elegans

Di(2-ethylhexyl)phthalate (DEHP) is an ubiquitous and emerging contaminant that is widely present in food, agricultural crop, and the environment, posing a potential risk to human health. This study utilized the nematode Caenorhabditis elegans to decipher the toxic effects of early life exposure to DEHP on aging and its underlying mechanisms. The results showed that exposure to DEHP at 0.1 and 1.5 mg/L inhibited locomotive behaviors. In addition, DEHP exposure significantly shortened the mean lifespan of the worms and further adversely affected pharyngeal pumping rate and defecation cycle in aged worms. Moreover, DEHP exposure also further enhanced accumulation of age-related biomarkers including lipofuscin, lipid peroxidation, and intracellular reactive oxygen species in aged worms. In addition, exposure to DEHP significantly suppressed gene expression of hsp-16.1, hsp-16.49, and hsp-70 in aged worms. Further evidences showed that mutation of genes involved in insulin/IGF-1-like signaling (IIS) pathway (daf-2, age-1, pdk-1, akt-1, akt-2, and daf-16) restored lipid peroxidation accumulation upon DEHP exposure in aged worms, whereas skn-1 mutation resulted in enhanced lipid peroxidation accumulation. Therefore, IIS and SKN-1 may serve as an important molecular basis for DEHP-induced age-related declines in C. elegans. Since IIS and SKN-1 are highly conserved among species, the age-related declines caused by DEHP exposure may not be exclusive in C. elegans, leading to adverse human health consequences due to widespread and persistent DEHP contamination in the environment.

Mediation analysis for the relationship between urinary phthalate metabolites and type 2 diabetes via oxidative stress in a population in Jeddah, Saudi Arabia

Human exposure to phthalates is ubiquitous and has received considerable attention due to their association with adverse health outcomes, including type 2 diabetes mellitus (T2DM). Nevertheless, earlier studies that link phthalate exposure to T2DM yielded ambiguous results. Furthermore, studies that associate phthalate exposure with oxidative stress and then with T2DM are scant. In this diabetic case-control study, urine samples collected from 101 individuals aged 28-68 years from Jeddah, Saudi Arabia, were analyzed to determine 20 phthalate metabolites (PhMs) and seven oxidative stress biomarkers (OSBs). Unconditional logistic regression was used to estimate odds ratios for the association between diabetes and urinary PhMs and OSBs in participants, stratified by age, gender, nationality, smoking status, occupation, and urinary creatinine. Twelve PhMs and five OSBs were found at detection rates above 50%, with geometric mean concentrations of 0.61-100 and 0.35-10.7 ng/mL (1.04-171 and 0.61-18.6 μg/g creatinine), respectively. Almost all exposures were significantly higher in diabetic cases than in controls. The 12 PhMs were positively associated with higher urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F_2α (8-PGF_2α). Individuals in the 3rd and/or 4th quartile(s) for urinary concentrations of PhMs and OSBs showed 3.7- and 7.3-fold increase, respectively, in the odds of having diabetes compared with those in the 1st quartile. The rank order of association of PhMs/OSBs with diabetes followed the order of: mEP ≈ mBP > mEHP > mCPP > mECPP ≈ mEOHP ≈ mEHHP ≈ mIBP ≈ mMP > mCMHP ≈ mBzP and 8-OHdG > 8-PGF_2α ≈ 15-PGF_2α. The relationship between phthalate exposure and risk of developing T2DM was mediated in part by phthalate-induced oxidative stress, especially 8-OHdG. Our study suggests that human exposure to phthalates is associated with increased oxidative stress which mediates the development of T2DM.

Systematic review and meta-analysis on the association between phthalates exposure and insulin resistance

This study aims to provide an overview of human studies on the association of exposure to phthalates and insulin resistance. We systematically searched human studies available until 15 January 2018.We conducted a literature search in Scopus, ISI Web of Science, PubMed, Google Scholar, and Cochrane Collaboration. We used the following keywords to identify relevant articles: "phthalate", "phthalate ester", "metabolic syndrome", "insulin resistance", "glucose intolerance", and "diabetes". For analyzing data, we conducted meta-analysis using the Stata software. We appraised each study to examine the sources of heterogeneity, including difference in clinical outcomes and exposure measurements. To determine the robustness and whether some of the factors have the highest impact on the results of the present meta-analysis, several sensitivity analyses were conducted. Sensitivity analysis showed that by removing studies with the highest weight and age groups, no change was observed in heterogeneity. Moreover, with excluding the study conducted in Europe, the results remained unchanged and constant. In addition, the funnel plot and Egger's tests were executed to access publication bias. Both the funnel plots and Egger's test did not show any evidence of publication bias (P = 0.31). In the random effects meta-analysis of all studies (n = 8), the pooled correlation coefficient between phthalate exposure and HOMA-IR was 0.10 (95% CI; 0.07-0.12, P < 0.001), with significant heterogeneity (P < 0.001, I² = 85.5%). Our findings revealed positive association between exposure to phthalate metabolites and increased HOMA-IR; this association remained significant even after adjusting the analysis for multiple confounding variables.

Serum concentrations of bisphenol A and its alternatives in elderly population living around e-waste recycling facilities in China: Associations with fasting blood glucose

In the present study, concentrations of bisphenol A (BPA) and its six alternatives were quantified in serum samples collected from elder population living around an e-waste recycling facilities as well as an reference area in China. BPA, bisphenol AF (BPAF), and bisphenol F (BPF) were frequently detected (detection rates: > 65%) in serum samples collected from residents living near e-waste dismantling facilities, with geometric mean (GM) concentrations of 3.2, 0.0074, and 0.062 ng/mL, respectively. The detection frequencies of other four bisphenols (BPs) in serum samples were lower than 25%, regardless of the sampling areas. Significant difference (Mann-Whitney U-test, p < 0.05) was observed in the serum concentration of BPA, but not BPAF and BPF, between the e-waste recycling and reference areas. This finding indicated e-waste dismantling activities are correlated with human BPA exposure. Significant higher (p < 0.05) detection rates of donors who had abnormal fasting blood glucose (FBG) levels were found in e-waste recycling areas (45%) than those found in reference area. Our results suggested BPA and BPAF exposure might associated with abnormal FBG in participants living in e-waste sites. To our knowledge, this study is first determination of BPs in serum samples and assessment of health risk of elderly people from BPs exposure in e-waste dismantling area.

The role of oxidative stress in cardiometabolic risk related to phthalate exposure in elderly diabetic patients from Shanghai

The effect of human exposure to phthalates and consequent contribution to the development of cardiometabolic health problems is unknown. However, oxidative stress has been established as playing an important role in the pathogenesis of cardiometabolic outcomes. In this study, we aimed to explore whether exposure to phthalate metabolites could induce cardiometabolic risk by increasing oxidative stress in a diabetic population from Shanghai. We collected paired blood and urine samples from a total of 300 volunteers, and measured 10 phthalate metabolites in urine and biomarkers of oxidative stress from serum including glucose and lipid levels, and liver and kidney damage. The insulin resistance (IR) risk was assessed by the surrogate indices including homeostasis model assessment-insulin resistance (HOMA-IR) and triglyceride glucose (TyG). We used multivariable linear regression to assess the association between phthalates and these physiological parameters. Mediation and modification analyses were performed to identify the role that oxidative stress played in the underlying mechanisms. The results showed that most of the determined phthalate metabolites were positively associated with HOMA-IR, 8‑hydroxy‑2'‑deoxyguanosine (8-OHDG), and malondialdehyde (MDA). In the mediation analysis, only γ‑glutamiltransferase (GGT) was found to be a significant mediator of the association between phthalates and TyG. In the modification analysis, exposure to phthalates strengthened the association between oxidative stress (MDA and 8-OHDG) and HOMA-IR. Our findings demonstrate that exposure to phthalates might be positively associated with elevated IR and oxidative stress. The direct participation (mediation effect) of GGT might play an important mechanism in promoting IR.

Percentage fractions of urinary di(2-ethylhexyl) phthalate metabolites: Association with obesity and insulin resistance in Korean girls

OBJECTIVE

We assessed the associations of percentage fractions of urinary di(2-ethylhexyl) phthalate (DEHP) metabolites with obesity and insulin resistance in Korean girls.

METHODS

In total, 137 girls, aged 6 to 13 years (65 overweight cases and 72 controls), were recruited. Anthropometric indices and the homeostatic model assessment of insulin resistance (HOMA-IR) index were determined. Four major urinary DEHP metabolites were analyzed in spot urine samples by gas chromatography-tandem mass spectrometry, including mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono(2-ethyl-5-carboxypentyl) phthalate.

RESULTS

There were no significant differences in the urinary concentrations of the DEHP metabolites between the overweight and control groups. The percentage fraction of MEHHP (MEHHP%) among all DEHP metabolites was significantly higher in the overweight prepubertal girls than in the controls (P = 0.035). MEHHP% was positively associated with the body mass index percentile, waist circumference, body fat percentage, and HOMA-IR index in the prepubertal girls. After adjusting for covariates, the prepubertal girls in a higher MEHHP% quartile were found to have a higher odds ratio for central obesity than those in a lower quartile (odds ratios: 5.05 for quartile 3; 7.30 for quartile 4). The relative rate of MEHHP oxidation to MEOHP was negatively associated with the body mass index percentile and waist circumference in the prepubertal girls. However, no such association was observed in the pubertal girls.

CONCLUSIONS

MEHHP% was positively associated with obesity and insulin resistance in prepubertal girls. Further studies are necessary to elucidate the causal links between altered phthalate metabolism and increased susceptibility to insulin resistance in children.

Mitochondria as target of endocrine-disrupting chemicals: implications for type 2 diabetes

Type 2 diabetes is a chronic, heterogeneous syndrome characterized by insulin resistance and pancreatic β-cell dysfunction or death. Among several environmental factors contributing to type 2 diabetes development, endocrine-disrupting chemicals (EDCs) have been receiving special attention. These chemicals include a wide variety of pollutants, from components of plastic to pesticides, with the ability to modulate endocrine system function. EDCs can affect multiple cellular processes, including some related to energy production and utilization, leading to alterations in energy homeostasis. Mitochondria are primarily implicated in cellular energy conversion, although they also participate in other processes, such as hormone secretion and apoptosis. In fact, mitochondrial dysfunction due to reduced oxidative capacity, impaired lipid oxidation and increased oxidative stress has been linked to insulin resistance and type 2 diabetes. Herein, we review the main mechanisms whereby metabolism-disrupting chemical (MDC), a subclass of EDCs that disturbs energy homeostasis, cause mitochondrial dysfunction, thus contributing to the establishment of insulin resistance and type 2 diabetes. We conclude that MDC-induced mitochondrial dysfunction, which is mainly characterized by perturbations in mitochondrial bioenergetics, biogenesis and dynamics, excessive reactive oxygen species production and activation of the mitochondrial pathway of apoptosis, seems to be a relevant mechanism linking MDCs to type 2 diabetes development.

Phthalates and type 1 diabetes: is there any link?

Phthalates are a group of chemical compounds used as plasticizers in the manufacture of plastic materials. They can be present in many commonly used products. There seems to be a relationship between exposure to phthalates and the occurrence of metabolic dysfunctions, such as a decrease in glucose tolerance, oxidative stress, loss of beta cells, and a decrease in insulin synthesis. As beta cells play a key role in the onset of type 1 diabetes mellitus (T1DM), we sought to investigate the relationship between exposure to phthalates and the diagnosis of T1DM in prepubertal children. Design concentrations of phthalate metabolites were compared in the urine of a population of prepubertal children with new-onset diabetes, patients with T1DM diagnosed more than 6 months previously, and healthy control children. Although the concentrations of DBP and DiBP metabolites were statistically identical in the new-onset diabetes, diabetes, and control groups, there was a clear trend for higher levels of DiBP metabolites in the children with new-onset diabetes. In our sample, there was a trend for higher levels of DiBP metabolites in children with new-onset diabetes.

Toxic Effects of Di-2-ethylhexyl Phthalate: An Overview

Di-2-ethylhexyl phthalate (DEHP) is extensively used as a plasticizer in many products, especially medical devices, furniture materials, cosmetics, and personal care products. DEHP is noncovalently bound to plastics, and therefore, it will leach out of these products after repeated use, heating, and/or cleaning of the products. Due to the overuse of DEHP in many products, it enters and pollutes the environment through release from industrial settings and plastic waste disposal sites. DEHP can enter the body through inhalation, ingestion, and dermal contact on a daily basis, which has raised some concerns about its safety and its potential effects on human health. The main aim of this review is to give an overview of the endocrine, testicular, ovarian, neural, hepatotoxic, and cardiotoxic effects of DEHP on animal models and humans in vitro and in vivo.

Di-(2-ethylhexyl)-phthalate induces glucose metabolic disorder in adolescent rats

As a plasticizer, di-(2-ethylhexyl)-phthalate (DEHP) is widely added in various commercial products. Some researchers had suggested that DEHP has adverse effects on the glucose metabolism, but the mechanisms remain unclear. Adolescent Wistar rats were divided into four groups and administered DEHP by gavage at 0, 5, 50, and 500 mg kg^-1 d^-1 for 28 days. ELISA was used to quantify the serum insulin and leptin levels; RT-PCR, immunohistochemistry, and Western blot were used to detect the mRNA and protein expressions of Janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling 3 (SOCS3), leptin receptor (Ob-R), and insulin receptor (IR) in liver and pancreas In comparison to the control group, the DEHP-treated rats showed the following: (1) higher organ coefficient of liver; (2) higher fasting blood glucose levels, higher fasting serum insulin and leptin levels, higher insulin resistance index homeostasis model assessment; (3) lower protein levels of Ob-R and IR in the liver and pancreas; (4) higher protein levels of JAK2 and STAT3 in the liver; and (5) higher protein and mRNA levels of SOCS3 in the liver and pancreas. Exposure to DEHP induced glucose metabolic disorder in the adolescent rats, and the mechanism is that DEHP may interfere with the JAK2/STAT3/SOCS3 pathway, regulated the sensitivity of the insulin receptor and leptin receptor.

The associations between phthalate exposure and insulin resistance, β-cell function and blood glucose control in a population-based sample

In developed countries, phthalate exposure is ubiquitous. Previous studies have shown an association between phthalate levels and health effects. To test associations between phthalate exposures, estimated from urinary phthalate metabolites, and insulin resistance, β-cell function and glucose control. Data were obtained from a cross-sectional, nationally representative study; the Canadian Health Measures Survey (CHMS, 2009-2011). Participants under the age of 12, those with diabetes, who were pregnant or who had not fasted overnight were excluded. Fasting blood glucose, insulin, and glycosylated hemoglobin (HbA_1C) levels were measured in a subset of participants, and urine was collected for creatinine and phthalate metabolites. We tested associations between these variables using linear regression analysis. Of 4437 participants (12-79years old), 2119 had fasting glucose measurements and at least one phthalate metabolite above detection limits. MBzP, MCPP, MEHP, MEHHP, MiBP, and the sum of DEHP metabolites were positively associated with increased HbA_1C (p<0.05). DEHP metabolites were positively associated with increased fasting glucose, insulin, HOMA-IR and HOMA-β. An interquartile increase in the sum of log transformed DEHP metabolites was associated with increases in HOMA-IR and HOMA-β of 0.15 (95% CI 0.04, 0.26) and 10.24 (95% CI 3.71, 16.77) respectively. Increased concentrations of all measured phthalate metabolites were associated with reduced blood glucose control. DEHP metabolites were also associated with increased glucose concentrations, and indicators of β-cell function and insulin resistance. Our results suggest that exposure to phthalates may possibly impair control of blood glucose and thereby predispose to pre-diabetes.

Immune System: An Emerging Player in Mediating Effects of Endocrine Disruptors on Metabolic Health

The incidence of metabolic disorders like type 2 diabetes and obesity continues to increase. In addition to the well-known contributors to these disorders, such as food intake and sedentary lifestyle, recent research in the exposure science discipline provides evidence that exposure to endocrine-disrupting chemicals like bisphenol A and phthalates via multiple routes (e.g., food, drink, skin contact) also contribute to the increased risk of metabolic disorders. Endocrine-disrupting chemicals (EDCs) can disrupt any aspect of hormone action. It is becoming increasingly clear that EDCs not only affect endocrine function but also adversely affect immune system function. In this review, we focus on human, animal, and in vitro studies that demonstrate EDC exposure induces dysfunction of the immune system, which, in turn, has detrimental effects on metabolic health. These findings highlight how the immune system is emerging as a novel player by which EDCs may mediate their effects on metabolic health. We also discuss studies highlighting mechanisms by which EDCs affect the immune system. Finally, we consider that a better understanding of the immunomodulatory roles of EDCs will provide clues to enhance metabolic function and contribute toward the long-term goal of reducing the burden of environmentally induced diabetes and obesity.