Diabetes in relation to serum levels of polychlorinated biphenyls and chlorinated pesticides in adult Native Americans

Comprehensive metabolic profiling of dioxin-like compounds exposure in laying hens: Implications for toxicity assessment

The evaluation of toxicity related to polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) is crucial for a comprehensive risk assessment in real-world exposure scenarios. This study employed a controlled feeding experiment to investigate the metabolic effects of dioxin-like compounds (DLCs) on laying hens via feed exposure. Diets enriched with two concentrations (1.17 and 5.13 pg toxic equivalents (TEQ)/g dry weight (dw)) were administered over 14 days, followed by 28 days of clean feed. Metabolomics analyses of blood samples revealed significant metabolic variations between PCDD/Fs and DL-PCBs exposed groups and controls, reflecting the induced metabolic disruption. Distinct changes were observed in sphingosine, palmitoleic acid, linoleate, linolenic acid, taurocholic acid, indole acrylic acid, and dibutyl phthalate levels, implying possible connections between PCDD/Fs and DL-PCBs toxic effects and energy-neuronal imbalances, along with lipid accumulation and anomalous amino acid metabolism, impacting taurine metabolism. Moreover, we identified three differential endogenous metabolites-L-tryptophan, indole-3-acetaldehyde, and indole acrylic acid-as potential ligands for the aryl hydrocarbon receptor (AhR), suggesting their role in mediating PCDD/Fs and DL-PCBs toxicity. This comprehensive investigation provides novel insights into the metabolic alterations induced by PCDD/Fs and DL-PCBs in laying hens, thereby enhancing our ability to assess risks associated with their exposure in human populations.

Factors affecting the polychlorinated biphenyl signatures in serum of adults living in a highly polluted area in eastern Slovakia

Introduction

Over the years eastern Slovakia has been subject to consistent monitoring of high levels of polychlorinated biphenyls (PCBs) in both the environment and human populations attributed to the former production of PCBs at the Chemko Strážske plant. We aimed to investigate the extent to which dietary habits and residential location could affect the concentrations of PCBs in the blood serum samples of subjects.

Methods

We enrolled 602 adult subjects from eastern Slovakia with an average age of 45.14 (±8.49) years. To determine the concentrations of 21 PCB congeners, we used solid phase extraction along with gas chromatography coupled with high-resolution mass spectrometry. Based on questionnaire data, the assessment of dietary habits and residential location was performed using score calculations and creating a map.

Results and discussion

Through principal component analysis, the 20 PCB congeners were classified into three groups: PC1, comprising highly chlorinated PCBs, and PC2 and PC3, consisting primarily of low chlorinated PCBs. Stepwise multivariate regression revealed positive and negative associations between PCB congeners represented by PC1-3 and scores related to the residential location and scores related to food consumption, respectively. We confirmed that levels of PCBs represented by PC1-3 increased with age. The geographical proximity to pollution sources proved to be a key contributing factor to the observed PCB levels in individuals residing in eastern Slovakia.

Serum concentration of polychlorinated biphenyls and the risk of type 2 diabetes: a 10-year follow-up historical cohort study

This study investigated the association between serum concentrations of Polychlorinated Biphenyls (PCBs) and the risk of type 2 diabetes within the general population. A ten-year follow-up historical cohort study was conducted during 2009-2019 as part of the Bushehr MONICA cohort study in Iran. Of 893 non-diabetes participants at base line, 181 individuals were included in the study. The concentration of nine PCB congeners was measured in individuals' serum samples at baseline, and the risk of type 2 diabetes was determined based on fasting blood sugar at the end of follow-up. Multiple logistic regression models were used to assess the study outcomes after adjusting for covariates. This study included 59 diabetes individuals (32.6%; mean [SD] age: 58.64 [8.05]) and 122 non-diabetes individuals (67.4%; mean [SD] age: 52.75 [8.68]). Multivariable analysis revealed that a one-tertile increase (increasing from 33rd centile to 67th centile) in Σ non-dioxin-like-PCBs (OR 2.749, 95% CI 1.066-7.089), Σ dioxin-like-PCBs (OR 4.842, 95% CI 1.911-12.269), and Σ PCBs (OR 2.887, 95% CI 1.120-7.441) significantly associated with an increased risk of type 2 diabetes. The strongest association was obtained for dioxin-like PCBs. The results highlight a significant correlation between PCB exposure and an increased risk of type 2 diabetes. The evidence suggests that additional epidemiological studies are necessary to clarify the link between PCBs and diabetes.

Combined effects of organochlorine pesticides on type 2 diabetes mellitus: Insights from endocrine disrupting effects of hormones

Association between organochlorine pesticides (OCPs) exposure and type 2 diabetes mellitus (T2DM) remains contradictory, and the evidence is mostly focused on a single exposure. Here, we assessed the associations between individual and combined OCPs exposure and T2DM, and explored the underlying mechanism of sex hormones and the methylation levels of sex hormone receptors in above associations. A case-control study with 1812 participants was performed. Gas chromatography mass spectrometry, liquid chromatography-tandem mass spectrometry, and pyrosequencing were used to measure plasma OCPs, serum sex hormones, and whole blood methylation levels of sex hormone receptors, respectively. Generalized linear models were used to analyze the relationships between OCPs, sex hormones, the methylation levels of sex hormone receptors, and T2DM. Quantile based g-computation (QGC) and Bayesian Kernel Machine Regression (BKMR) were employed to assess the combined OCPs exposure. The roles of sex hormones and the methylation levels of their receptors were evaluated by moderating mediation models. After adjusting for covariates, each unit (2.718 ng/ml) increase in p,p'-DDE was associated with a higher risk of T2DM in males (odds ratio (OR) and 95% confidence interval (CI): 1.066 (1.023, 1.112)). QGC and BKMR showed a positive combined effect in the associations of OCPs mixtures on T2DM among premenopausal females, and positive effects but not statistically significant among males and postmenopausal females. p,p'-DDE was the largest contributor for the positive associations. Furthermore, testosterone mediated 21.149% of the associations of p,p'-DDE with T2DM moderated by the androgen receptor methylation (ARm) located in CpG island 1. Individual and mixtures of OCPs exposure were positively linked to elevated risk of T2DM. Testosterone and ARm may participate in the related processes of OCPs with T2DM, providing new insights into the adverse endocrine effects caused by OCPs and specific pathways for the etiology and control of diabetes.

Association of hair polychlorinated biphenyls and multiclass pesticides with obesity, diabetes, hypertension and dyslipidemia in NESCAV study

Obesity, diabetes, hypertension and dyslipidemia are well-established risk factors for cardiovascular diseases (CVDs), and have been associated with exposure to persistent organic pollutants. However, studies have been lacking as regards effects of non-persistent pesticides on CVD risk factors. Here, we investigated whether background chronic exposure to polychlorinated biphenyls (PCBs) and multiclass pesticides were associated with the prevalence of these CVD risk factors in 502 Belgian and 487 Luxembourgish adults aged 18-69 years from the Nutrition, environment and cardiovascular health (NESCAV) study 2007-2013. We used hair analysis to evaluate the chronic internal exposure to three PCBs, seven organochlorine pesticides (OCs) and 18 non-persistent pesticides. We found positive associations of obesity with hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and chlorpyrifos, diabetes with pentachlorophenol (PCP), fipronil and fipronil sulfone, hypertension with PCB180 and chlorpyrifos, and dyslipidemia with diflufenican and oxadiazon, among others. However, we also found some inverse associations, such as obesity with PCP, diabetes with γ-HCH, hypertension with diflufenican, and dyslipidemia with chlorpyrifos. These results add to the existing evidence that OC exposure may contribute to the development of CVDs. Additionally, the present study revealed associations between CVD risk factors and chronic environmental exposure to currently used pesticides such as organophosphorus and pyrethroid pesticides.

Polychlorinated biphenyls and risk of metabolic syndrome and comparison with the risk of diabetes: A systematic review and meta-analysis

With the increasing incidence of metabolic syndrome (MetS) worldwide and no consistent results on PCBs and MetS. A meta-analysis to explore their relationship was conducted. Given the high correlation and overlap of MetS with diabetes, analysis of diabetes risk, was used as a supplement to compare with MetS. Seven studies included MetS, 15 studies for diabetes, and one study included both outcomes. It was found that PCBs may not be a risk factor for MetS, but their high heterogeneity indicates that they are under-represented. In addition, our results showed that total PCBs might be a protective factor against diabetes. In the whole blood subgroup, which can reflect the accumulation of more than one body load, heterogeneity was reduced, and its OR value suggested that PCBs increased the risk of MetS in the whole blood biomaterial. DL-PCBs were positively associated with MetS and diabetes, while NDL-PCBs were negatively associated with diabetes. In the subgroup analysis of PCBs homologs, DL-PCB-126 and DL-PCB-118 were risk factors for MetS and diabetes, respectively. In addition, PCB-153 and 180 showed a dose-response relationship between them and diabetes mellitus, respectively. The results of total analysis of MetS and diabetes mellitus and subgroup analysis of PCBs were mixed, and this reason might be attributed to the different mechanisms of action and effect sizes of different PCBs, so based on subgroup results and in vivo and in vitro experiments, we considered PCBs to be a risk factor for MetS and diabetes. Due to various reasons, there are still many shortcomings in the evaluation of PCBs impact on human health, and more high-quality research are needed to further explore the role of PCBs of different species and congeners in MetS and diabetes.

Pesticides and insulin resistance-related metabolic diseases: Evidences and mechanisms

The use of pesticides in the past century has lot helped humankind in improving crops' field and general hygiene level. Nevertheless, there has been countless evidences on the toxic effects of pesticides on the living systems. The link of exposure to pesticides with different human chronic diseases in the context of carcinogenicity, neurotoxicity, developmental toxicity, etc., have been evaluated in various types of studies. There are also some evidences on the link of exposure to pesticides with higher incidence of metabolic diseases associated with insulin resistance like diabetes, obesity, metabolic syndrome, hypertension, polycystic ovary syndrome and chronic kidney diseases. Physiologically, weakening intracellular insulin signaling is considered as a compensatory mechanism for cells to cope with cellular stresses like xenobiotic effects, oxidative stress and inflammatory responses, but it can pathologically lead to a defective cycle with lowered sensitivity of the cells to insulin which happens in metabolic disorders. In this work, the data related to metabolic toxicity of pesticides categorized in the mentioned metabolic diseases with a focus on the effects of pesticides on insulin signaling pathway and the mechanisms of development of insulin resistance will be systematically reviewed and presented.

Gene-environment interaction in long-term effects of polychlorinated biphenyls exposure on glucose homeostasis and type 2 diabetes: The modifying effects of genetic risk and lifestyle

The longitudinal relationships of polychlorinated biphenyls (PCBs) exposure with glucose homeostasis and type 2 diabetes (T2D) risk among Chinese population have not been assessed, and interactions of PCB exposure with genetic susceptibility and lifestyle are unclear. In this prospective cohort study, fasting plasma glucose (FPG) and insulin (FPI) and seven serum indicator-PCBs were measured for each participant. We constructed polygenic risk score (PRS) of T2D and healthy lifestyle score. Each 1-unit increment of ln-transformed PCB-118 was related with a 0.141 mmol/L, 11.410 pmol/L, 0.661, and 74.5% increase in FPG, FPI, homeostasis model assessment of insulin resistance, and incident T2D risk over 6 years, respectively. Each 1-unit increment in T2D-PRS was related with a 0.169 mmol/L elevation of FPG and 65.5% elevation of incident T2D risk during 6 years. Compared with participants who had low T2D-PRS and low PCB-118, participants with high T2D-PRS and high PCB-118 showed a significant increase in FPG (0.162 mmol/L; P for interaction <0.001) and incident T2D risk [hazard ratio (HR)= 2.222]. Participants with low PCB-118, low PRS, and healthy lifestyle had the lowest incident T2D risk (HR=0.232). Our findings highlighted the significance of reducing PCB exposure and improvement in lifestyle for T2D prevention and management, especially for individuals with higher genetic risk of T2D.

The diabetogenic effects of pesticides: Evidence based on epidemiological and toxicological studies

While the use of pesticides has improved grain productivity and controlled vector-borne diseases, the widespread use of pesticides has resulted in ubiquitous environmental residues that pose health risks to humans. A number of studies have linked pesticide exposure to diabetes and glucose dyshomeostasis. This article reviews the occurrence of pesticides in the environment and human exposure, the associations between pesticide exposures and diabetes based on epidemiological investigations, as well as the diabetogenic effects of pesticides based on the data from in vivo and in vitro studies. The potential mechanisms by which pesticides disrupt glucose homeostasis include induction of lipotoxicity, oxidative stress, inflammation, acetylcholine accumulation, and gut microbiota dysbiosis. The gaps between laboratory toxicology research and epidemiological studies lead to an urgent research need on the diabetogenic effects of herbicides and current-use insecticides, low-dose pesticide exposure research, the diabetogenic effects of pesticides in children, and assessment of toxicity and risks of combined exposure to multiple pesticides with other chemicals.

Insight into the physiological and pathological roles of the aryl hydrocarbon receptor pathway in glucose homeostasis, insulin resistance, and diabetes development

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcriptional factor that mediates the toxicities of several environmental pollutants. Decades of research have been carried out to understand the role of AhR as a novel mechanism for disease development. Its involvement in the pathogenesis of cancer, cardiovascular diseases, rheumatoid arthritis, and systemic lupus erythematosus have long been known. One of the current hot research topics is investigating the role of AhR activation by environmental pollutants on glucose homeostasis and insulin secretion, and hence the pathogenesis of diabetes mellitus. To date, epidemiological studies have suggested that persistent exposure to environmental contaminants such as dioxins, with subsequent AhR activation increases the risk of specific comorbidities such as obesity and diabetes. The importance of AhR signaling in various molecular pathways highlights that the role of this receptor is far beyond just xenobiotic metabolism. The present review aims at providing significant insight into the physiological and pathological role of AhR and its regulated enzymes, such as cytochrome P450 1A1 (CYP1A1) and CYP1B1 in both types of diabetes. It also provides a comprehensive summary of the current findings of recent research studies investigating the role of the AhR/CYP1A1 pathway in insulin secretion and glucose hemostasis in the pancreas, liver, and adipose tissues. This review further highlights the molecular mechanisms involved, such as gluconeogenesis, hypoxia-inducible factor (HIF), oxidative stress, and inflammation.

Persistent organic pollutant exposure contributes to Black/White differences in leukocyte telomere length in the National Health and Nutrition Examination Survey

Despite racial disparities in diseases of aging and premature mortality, non-Hispanic Black Americans tend to have longer leukocyte telomere length (LTL), a biomarker of cellular aging, than non-Hispanic White Americans. Previous findings suggest that exposure to certain persistent organic pollutants (POPs) is both racially-patterned and associated with longer LTL. We examine whether Black/White differences in LTL are explained by differences in exposure to 15 POPs by estimating the indirect effect (IE) of self-reported race on LTL that is mediated through nine polychlorinated biphenyls (PCBs), three furans, and three dioxins, as well as their mixtures. Our study population includes 1,251 adults from the 1999-2000 and 2001-2002 cycles of the cross-sectional National Health and Nutrition Examination Survey. We characterized single-pollutant mediation effects by constructing survey-weighted linear regression models. We also implemented various approaches to quantify a global mediation effect of all POPs, including unpenalized linear regression, ridge regression, and examination of three summary exposure scores. We found support for the hypothesis that exposure to PCBs partially mediates Black/White differences in LTL. In single-pollutant models, there were significant IEs of race on LTL through six individual PCBs (118, 138, 153, 170, 180, and 187). Ridge regression (0.013, CI 0.001, 0.023; 26.0% mediated) and models examining summative exposure scores with linear combinations derived from principal components analysis (0.019, CI 0.009, 0.029; 34.8% mediated) and Toxic Equivalency Quotient (TEQ) scores (0.016, CI 0.005, 0.026; 28.8% mediated) showed significant IEs when incorporating survey weights. Exposures to individual POPs and their mixtures, which may arise from residential and occupational segregation, may help explain why Black Americans have longer LTL than their White counterparts, providing an environmental explanation for counterintuitive race differences in cellular aging.

An evidence map of polychlorinated biphenyl exposure and health outcome studies among residents of the Akwesasne Mohawk Nation

From the 1950s to the 1970s, three Superfund sites discharged polychlorinated biphenyl (PCB)-contaminated waste upstream of the Mohawk Nation at Akwesasne, resulting in PCB contamination of groundwater, soil, and sediment in the surrounding area. Given the persistence of PCBs in the environment and in human tissues, there are continued concerns regarding PCB exposures and the potential for adverse health effects in the community. We developed an evidence map of PCB research at Akwesasne in order to characterize the available data and to highlight potential research needs. Human health and exposure biomarker studies were identified from a literature search based on population, exposure, comparator, and outcome (PECO) criteria. Data extracted from references that met the inclusion criteria after full-text review included study characteristics (e.g., sample size, study design, sampling years), details on PCB measurements (e.g., analytical method, number of congeners analyzed, method detection limits), and results (e.g., PCB levels and summary of study conclusions). We identified 33 studies, conducted between 1986 and 2013, that examined PCB exposure characteristics and health effects in residents of the Akwesasne Mohawk Nation. Organizing this literature into an evidence map including information on study cohort, congener groupings, exposure biomarker characteristics, and health effects allowed us to identify research gaps and to suggest future research priorities for the community. We identified current PCB exposure levels and PCB source characterization as major uncertainties, both of which could be addressed by new studies of PCB concentrations in environmental media.

Environmental Stressors and the PINE Network: Can Physical Environmental Stressors Drive Long-Term Physical and Mental Health Risks?

Both psychosocial and physical environmental stressors have been linked to chronic mental health and chronic medical conditions. The psycho-immune-neuroendocrine (PINE) network details metabolomic pathways which are responsive to varied stressors and link chronic medical conditions with mental disorders, such as major depressive disorder via a network of pathophysiological pathways. The primary objective of this review is to explore evidence of relationships between airborne particulate matter (PM, as a concrete example of a physical environmental stressor), the PINE network and chronic non-communicable diseases (NCDs), including mental health sequelae, with a view to supporting the assertion that physical environmental stressors (not only psychosocial stressors) disrupt the PINE network, leading to NCDs. Biological links have been established between PM exposure, key sub-networks of the PINE model and mental health sequelae, suggesting that in theory, long-term mental health impacts of PM exposure may exist, driven by the disruption of these biological networks. This disruption could trans-generationally influence health; however, long-term studies and information on chronic outcomes following acute exposure event are still lacking, limiting what is currently known beyond the acute exposure and all-cause mortality. More empirical evidence is needed, especially to link long-term mental health sequelae to PM exposure, arising from PINE pathophysiology. Relationships between physical and psychosocial stressors, and especially the concept of such stressors acting together to impact on PINE network function, leading to linked NCDs, evokes the concept of syndemics, and these are discussed in the context of the PINE network.

Associations of polychlorinated biphenyls exposure with plasma glucose and diabetes in general Chinese population: The mediating effect of lipid peroxidation

Polychlorinated biphenyls (PCBs) exposure has been related to the abnormal glucose metabolism and the risk of diabetes. However, the joint effects of various PCBs are uncertain and the potential mechanisms remain unclear. Our objectives were to evaluate the associations of serum PCBs with fasting plasma glucose (FPG) and the risk of diabetes among a general Chinese population, and to estimate the mediating effects of oxidative stress in the above associations. Serum levels of seven indicator-PCBs (PCB-28, 52, 101, 118, 138, 153, and 180) and FPG values were determined among 4498 subjects from the Wuhan-Zhuhai cohort. Oxidative DNA damage biomarker (urinary 8-hydroxy-2'-deoxyguanosine, 8-OHdG) and lipid peroxidation biomarker (urinary 8-isoprostane, 8-iso-PGF_2α) were also measured. Positive relationships of serum PCBs with FPG values as well as the risk of diabetes were observed. With each 1% increment in the natural log-transformed values of wet weight serum PCBs, FPG levels increased a 0.125% for PCB-52, 0.168% for PCB-118, 0.221% for PCB-138, 0.273% for PCB-153, and 0.379% for ΣPCB (the sum of seven PCBs). The adjusted odds ratios of diabetes associated with wet weight PCBs were 1.186 for PCB-52, 1.373 for PCB-118, 1.635 for PCB-153, and 1.456 for ΣPCB. The seven serum PCBs showed positive overall effect on the risk of diabetes. Elevated PCB-28, PCB-52, PCB-118, PCB-138, PCB-153, and ΣPCB were associated with the increased urinary 8-iso-PGF_2α, which was positively related with FPG values. Furthermore, urinary 8-iso-PGF_2α partially mediated the positive associations between PCBs and FPG values, with the mediated proportions ranged from 3.20 to 12.93%. In conclusion, our results suggested that serum PCBs were positively related with increased oxidative stress, FPG values, and the risk of diabetes among a general Chinese population. Serum PCBs mixture had positive overall effect on the risk of diabetes. Lipid peroxidation partly mediated the FPG elevation induced by PCB exposure.

Persistent organic pollutants and β-cell toxicity: a comprehensive review

Persistent organic pollutants (POPs) are a diverse family of contaminants that show widespread global dispersion and bioaccumulation. Humans are continuously exposed to POPs through diet, air particles, and household and commercial products; POPs are consistently detected in human tissues, including the pancreas. Epidemiological studies show a modest but consistent correlation between exposure to POPs and increased diabetes risk. The goal of this review is to provide an overview of epidemiological evidence and an in-depth evaluation of the in vivo and in vitro evidence that POPs cause β-cell toxicity. We review evidence for six classes of POPs: dioxins, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), flame retardants, and per- and polyfluoroalkyl substances (PFAS). The available data provide convincing evidence implicating POPs as a contributing factor driving impaired glucose homeostasis, β-cell dysfunction, and altered metabolic and oxidative stress pathways in islets. These findings support epidemiological data showing that POPs increase diabetes risk and emphasize the need to consider the endocrine pancreas in toxicity assessments. Our review also highlights significant gaps in the literature assessing islet-specific endpoints after both in vivo and in vitro POP exposure. In addition, most rodent studies do not consider the impact of biological sex or secondary metabolic stressors in mediating the effects of POPs on glucose homeostasis and β-cell function. We discuss key gaps and limitations that should be assessed in future studies.

Impact of Prenatal and Postnatal Exposure to Endocrine Disrupter DDT on Adrenal Medulla Function

Epinephrine is the most abundant catecholamine hormone, produced by the nervous system and adrenal glands. Endocrine disruption of epinephrine synthesis, secretion and signaling is less studied than steroid and thyroid hormones. Dichlorodiphenyltrichloroethane (DDT) is recognized as one of the most prominent environmental contaminants with a long half-life. It is a potent endocrine disrupter affecting sex steroid, mineralocorticoid, glucocorticoid and thyroid hormone production. Exposure to low doses of DDT is universal and begins in utero. Therefore, we studied adrenal medulla growth and function in male Wistar rats exposed to low doses of DDT during prenatal and postnatal development until puberty and adulthood, as well as rats exposed to DDT since the first day of postnatal development. All the exposed rats demonstrated lowered epinephrine blood levels, gradually reducing with age. DDT was found to inhibit the synthesis of tyrosine hydroxylase and affect the mitochondrial apparatus of epinephrine-producing cells during puberty and even after maturation. Low-dose exposure to DDT from birth resulted in more pronounced changes in adrenomedullary cells and a more profound decrease (up to 50%) in epinephrine secretion in adult rats. Prenatal onset of exposure demonstrated a mild effect on epinephrine-producing function (30% reduction), but was associated with lower rate of adrenal medulla growth during maturation and 25% smaller adrenal medullar size in adult rats. All subjects exposed to low doses of DDT failed to develop adaptive changes and restore proper epinephrine production. These results indicate a dysmorphogenetic effect of prenatal exposure and disruption of secretory function of adrenal chromaffin cells by postnatal exposure to DDT.

Pesticides and environmental injustice in the USA: root causes, current regulatory reinforcement and a path forward

Many environmental pollutants are known to have disproportionate effects on Black, Indigenous and People of Color (BIPOC) as well as communities of low-income and wealth. The reasons for these disproportionate effects are complex and involve hundreds of years of systematic oppression kept in place through structural racism and classism in the USA. Here we analyze the available literature and existing datasets to determine the extent to which disparities in exposure and harm exist for one of the most widespread pollutants in the world – pesticides. Our objective was to identify and discuss not only the historical injustices that have led to these disparities, but also the current laws, policies and regulatory practices that perpetuate them to this day with the ultimate goal of proposing achievable solutions. Disparities in exposures and harms from pesticides are widespread, impacting BIPOC and low-income communities in both rural and urban settings and occurring throughout the entire lifecycle of the pesticide from production to end-use. These disparities are being perpetuated by current laws and regulations through 1) a pesticide safety double standard, 2) inadequate worker protections, and 3) export of dangerous pesticides to developing countries. Racial, ethnic and income disparities are also maintained through policies and regulatory practices that 4) fail to implement environmental justice Executive Orders, 5) fail to account for unintended pesticide use or provide adequate training and support, 6) fail to effectively monitor and follow-up with vulnerable communities post-approval, and 7) fail to implement essential protections for children. Here we’ve identified federal laws, regulations, policies, and practices that allow for disparities in pesticide exposure and harm to remain entrenched in everyday life for environmental justice communities. This is not simply a pesticides issue, but a broader public health and civil rights issue. The true fix is to shift the USA to a more just system based on the Precautionary Principle to prevent harmful pollution exposure to everyone, regardless of skin tone or income. However, there are actions that can be taken within our existing framework in the short term to make our unjust regulatory system work better for everyone.

Evaluation of Early Biomarkers of Atherosclerosis Associated with Polychlorinated Biphenyl Exposure: An in Vitro and in Vivo Study

BACKGROUND

Miscellaneous cardiovascular risk factors have been defined, but the contribution of environmental pollutants exposure on cardiovascular disease (CVD) remains underappreciated.

OBJECTIVE

We investigated the potential impact of typical environmental pollutant exposure on atherogenesis and its underlying mechanisms.

METHODS

We used human umbilical vein endothelial cells (HUVECs) and apolipoprotein E knockout (ApoE-/-) mice to investigate how 2,3,5-trichloro-6-phenyl-[1,4]-benzoquinone (PCB29-pQ, a toxic polychlorinated biphenyl metabolite) affects atherogenesis and identified early biomarkers of CVD associated with PCB29-pQ exposures. Then, we used long noncoding RNAs (lncRNAs) HDAC7-AS1-overexpressing ApoE-/- mice and apolipoprotein E/caveolin 1 double-knockout (ApoE-/-/CAV1-/-) mice to address the role of these early biomarkers in PCB29-pQ-induced atherogenesis. Plasma samples from patients with coronary heart disease (CHD) were also used to confirm our findings.

RESULTS

Our data indicate that lncRNA HDAC7-AS1 bound to MIR-7-5p via argonaute 2 in PCB29-pQ-challenged HUVECs. Our mRNA sequencing assay identified transforming growth factor-β2 (TGF-β2) as a possible target gene of MIR-7-5p; HDAC7-AS1 sponged MIR-7-5p and inhibited the binding of TGF-β2 to MIR-7-5p. The effect of PCB29-pQ-induced endothelial injury, vascular inflammation, development of plaques, and atherogenesis in ApoE-/- mice was greater with MIR-7-5p-mediated TGF-β2 inhibition, whereas HDAC7-AS1-overexpressing ApoE-/- mice and ApoE-/-/CAV1-/- mice showed the opposite effect. Consistently, plasma levels of HDAC7-AS1 and MIR-7-5p were found to be significantly associated individuals diagnosed with CHD.

DISCUSSIONS

These findings demonstrated that a mechanism-based, integrated-omics approach enabled the identification of potentially clinically relevant diagnostic indicators and therapeutic targets of CHD mediated by environmental contaminants using in vitro and in vivo models of HUVECs and ApoE-/- and ApoE-/-/CAV1-/- mice. https://doi.org/10.1289/EHP9833.

Health risk assessment of exposure to organochlorine pesticides in the general population in Seoul, Korea over 12 years: A cross-sectional epidemiological study

This study evaluated the 12-year trends in serum levels of 28 organochlorine pesticides (OCPs) in 880 adults living in Seoul, Korea. The OCP levels decreased from 2006 to 2017, and p,p'-dichlorodiphenyldichloroethylene was a predominant compound. OCP levels were higher in females than in males, and showed positive associations with BMI and age. The OCP concentrations had inverted U-shaped associations with low-density lipoprotein cholesterol and total cholesterol. Concentrations of β-hexachlorocyclohexane were significantly higher in patients with hypertension than in participants that were normotensive. OCP levels showed positive associations with uric acid, creatinine, and thyroid-stimulating hormone, but negative associations with free thyroxine. Participants with diabetes had significantly higher OCP levels than those without it. Principal component analysis suggested possible differences in disease manifestation depending on the composition of OCPs. These results suggest that OCPs might disturb renal transport and thyroid homeostasis. To our knowledge, the inverted U-shaped associations of heptachlor epoxide and endosulfan with cholesterol, the epidemiological associations of trans-nonachlor and endosulfan with thyroid hormones, and the association of p,p'-DDE with hyperuricemia have not been previously reported in general population. This is the first long-term study to show trends of 28 OCPs in serum and associations with various health indicators in Korea.

Understanding Historical Trauma Among Urban Indigenous Adults at Risk for Diabetes

Historical trauma has been posited as a key framework for conceptualizing and addressing health equity in Indigenous populations. Using a community-based participatory approach, this study aimed to examine historical trauma and key psycho-social correlates among urban Indigenous adults at risk for diabetes to inform diabetes and other chronic disease prevention strategies. Indigenous adult participants (n=207) were recruited from an urban area in California and were asked to identify whether their Indigenous heritage was from a group in the United States, Canada, or Latin America. Historical trauma was assessed using the Historical Loss (HLS) and Historical Loss Associated Symptoms (HLAS) scales. Nearly half (49%) of Indigenous participants from the United States or Canada endorsed thinking about one or more historical losses weekly, daily, or several times a day, compared to 32% for Indigenous participants from Mexico, Central America, and South America. Most participants (62%) reported experiencing one or more historical loss-associated symptoms, such as depression and anger, sometimes, often, or always. Ancestry from the United States or Canada, depression, and participation in cultural activities were associated with greater HLS and HLAS scores, indicating a greater number of losses and associated symptoms. Results suggest a need to consider historical trauma when designing diabetes prevention interventions and the need to further consider ancestry differences. As preventive efforts for Indigenous adults expand in urban environments, behavioral interventions must incorporate strategies that address community-identified barriers in order to succeed.

Interactions among thyroid hormones and serum lipid levels in association with PCB exposure in the Mohawk Akwesasne population

Alterations in thyroid function and serum lipid levels were assessed in relation to exposure to polychlorinated biphenyls (PCBs) and three chlorinated pesticides (DDE, hexachorobenzene and mirex) in a sample of Akwesasne Mohawk adults. This population is highly exposed to PCBs because of living in close proximity to three aluminum foundries that used PCBs as hydraulic fluids, which then contaminated local fish, wildlife, water, air and soils. The goal was to assess interactions between thyroid function (TSH, T3, T4 and fT4) and serum lipids (cholesterol, triglycerides and total serum lipids) in relation to concentrations of 101 PCB congeners and three chlorinated pesticides. Previous studies in this population have shown that elevated concentrations of PCBs resulted in suppression of thyroid function in adolescents, and increased risk of clinical hypothyroidism in adults, as well as an elevation in serum lipids. However in adjusted analyses of PCB concentrations of 703 adults we find only small and inconsistent associations between serum PCB levels and thyroid function. The most striking observations were strong significant positive associations between TSH and T3 with serum lipids and a negative association with fT4 in women. Because elevated serum lipids increase risks of other diseases the respective roles of thyroid hormones and PCBs in regulation of serum lipids requires additional study.

Persistent organic pollutants-environmental risk factors for diabetes mellitus? - A population-based study

BACKGROUND

Globally, type-2 diabetes mellitus is increasing in epidemic proportions. A major cause of concern in India is the increasing incidence of cases, especially troubling is the observed increase in younger age groups with no risk factors. New evidence suggests that many environmental factors, such as air pollution, persistent organic pollutants (POPs), and environmental estrogens are implicated as risk factors for type-2 diabetes mellitus. Animal and human epidemiological studies have shown ubiquitous lipophilic substances, including POPs, are frequently associated with type-2 diabetes mellitus. Such studies have not been undertaken in Indian youth.

METHODS

This is a cross-sectional study that explored the association between POPs and type-2 diabetes mellitus in Indian urban and rural population. About 7 ml of venous blood was collected from all consenting patients and serum was separated immediately and was transported to the lab for further analysis. Serum levels of POPs, including organochlorine (OC) compounds and organophosphorus pesticides, were estimated using sample gas chromatography-mass spectrometry (GC-MS). The fasting blood sugar values and the serum levels of POPS were tested using Pearson correlation coefficient. The magnitude of increase in blood sugar corresponding to increase in POPs was analyzed using linear regression analysis. The odds ratios (ORs) were expressed at 95% confidence intervals (CIs).

RESULTS

Three OC pesticides and one organophosphate pesticide were strongly associated with increasing blood sugar levels after adjusting for age, sex, and body mass index - lindane (OR 4.95, 95% CI 1.03-23.73), DDT o, p' (OR 3.50, 95% CI 1.04-11.73), dimethoate (OR 19.31, 95% CI 4.22-88.37), and dichlorvas (OR 6.33, 95% CI 1.28-31.18).

The relationship between dietary exposure to persistent organic pollutants from fish consumption and type 2 diabetes among First Nations in Canada

OBJECTIVE

We previously examined the associations between dietary dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) intake from fish consumption and type 2 diabetes (T2D) prevalence in Ontario and Manitoba. This study aims to further explore the relationship in a regionally representative sample of First Nations adults living on-reserve across Canada.

METHODS

Dietary, health and lifestyle data collected by the cross-sectional First Nations Food, Nutrition and Environment Study (2008-2018) were analyzed. This participatory study included 6091 First Nations adult participants who answered questions on T2D. The consumption of locally caught fish was estimated with a food frequency questionnaire. A total of 551 samples from 96 fish species were collected and analyzed for the presence of DDE and PCBs. The associations between fish and dietary DDE/PCBs intake with self-reported T2D were investigated using multiple logistic regression models adjusted for confounders.

RESULTS

Dietary exposure to DDE (>2.11 ng/kg/bw) and PCBs (>1.47 ng/kg/bw) vs no exposure was positively associated with T2D with ORs of 2.33 (95% CI: 1.24-4.35) for DDE and 1.43 (95% CI: 1.01-3.59) for PCBs. The associations were stronger among females (DDE OR = 3.11 (1.41-6.88); PCBs OR = 1.76 (1.10-3.65)) and older individuals (DDE OR = 2.64 (1.12-6.20); PCBs OR = 1.44 (1.01-3.91)) as compared with males and younger participants. Also, significant dose-response relationships were found for fish consumption in females only.

CONCLUSION

This study confirms our previous findings that dietary DDE/PCBs exposure may increase the risk of T2D. The effect of DDE/PCBs from fish consumption is driven by geographical differences in DDE/PCBs concentrations in fish and by the amount of fish consumed, and is more prominent in females than in males.

The Ramapough Lunaape Nation: Facing Health Impacts Associated with Proximity to a Superfund Site

This study aimed to evaluate self-reported exposure to the Ringwood Mines/Landfill Superfund Site in relation to chronic health outcomes among members of the Ramapough Lunaape Turtle Clan nation and other local residents of Ringwood, New Jersey. Community surveys on personal exposure to the nearby Superfund site, self-reported health conditions, and demographics were conducted with 187 members of the Ramapough Lunaape Turtle Clan Nation and non-Native Americans residing in Ringwood, New Jersey from December 2015 to October 2016. Multiple logistic regression was performed to assess the association between ethnicity and a Superfund site exposure score developed for this study, as well as between exposure score and several chronic health conditions. Native Americans were 13.84 times (OR 13.84; 95% CI 4.32, 44.37) more likely to face exposure opportunities to Superfund sites as compared to non-Native Americans in the same New Jersey borough. For the entire surveyed cohort, increased Superfund site exposure routes was significantly associated with bronchitis (OR 4.10; 95% CI 1.18, 14.23). When the analyses were restricted to Native Americans, the association between self-reported Superfund site exposure and bronchitis remained significant (OR 17.42; 95% CI 1.99, 152.45). Moreover, the association between greater exposure score and asthma in this same population also reached statistical significance (OR 6.16; 95% CI 1.38, 27.49). This pilot study demonstrated a significant association between being a Ringwood resident of Native American ethnicity and self-declared opportunities for Superfund site exposure. It also showed a strong association between self-reported Superfund site exposure and the prevalence of bronchitis and asthma.

Chronic oral exposure to pesticides and their consequences on metabolic regulation: role of the microbiota

Pesticides have long been used in agriculture and household treatments. Pesticide residues can be found in biological samples for both the agriculture workers through direct exposure but also to the general population by indirect exposure. There is also evidence of pesticide contamination in utero and trans-generational impacts. Whilst acute exposure to pesticides has long been associated with endocrine perturbations, chronic exposure with low doses also increases the prevalence of metabolic disorders such as obesity or type 2 diabetes. Dysmetabolism is a low-grade inflammation disorder and as such the microbiota plays a role in its etiology. It is therefore important to fully understand the role of microbiota on the genesis of subsequent health effects. The digestive tract and mostly microbiota are the first organs of contact after oral exposure. The objective of this review is thus to better understand mechanisms that link pesticide exposure, dysmetabolism and microbiota. One of the key outcomes on the microbiota is the reduced Bacteroidetes and increased Firmicutes phyla, reflecting both pesticide exposure and risk factors of dysmetabolism. Other bacterial genders and metabolic activities are also involved. As for most pathologies impacting microbiota (including inflammatory disorders), the role of prebiotics can be suggested as a prevention strategy and some preliminary evidence reinforces this axis.

Persistent organic pollutants and couple fecundability: a systematic review

BACKGROUND

Despite increasing regulation, exposure to persistent organic pollutants (POPs) remains a serious public health concern due to their accumulation in the environment and ability to biomagnify up the food chain. POPs are associated with endocrine-disrupting effects including adverse reproductive outcomes that could affect fecundability, i.e. the capacity to conceive a pregnancy, quantified as time to pregnancy (TTP).

OBJECTIVE AND RATIONALE

Results of epidemiologic studies that examine the impact of various chemical classes of POPs on TTP have not been synthesised. We undertook a systematic review to summarise the strength of evidence for associations of four common groups of POPs with couple fecundability and to identify gaps and limitations in the literature in order to inform policy decisions and future research.

SEARCH METHODS

We performed an electronic search of literature published between 1 January 2007 and 6 August 2019 in MEDLINE, EMBASE.com, Global Health, DART/TOXLINE and POPLINE. We included empirical research papers that examined human exposure to organochlorine (OC) pesticides, brominated flame retardants, polychlorinated organic compounds and/or per- and polyfluoroalkyl substances (PFAS) and considered TTP or fecundability as an outcome. Standardised forms for screening, data extraction and study quality were developed using DistillerSR software, and all reviews were completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of fecundability studies.

OUTCOMES

The search returned 4573 articles, and 28 papers from 19 different studies met inclusion criteria. Among them, four studies measured TTP prospectively, three had data on participants' prenatal exposure, three examined associations in both male and female partners and one focused exclusively on males. Analyses varied widely in terms of exposure characterisation, precluding a meta-analytic approach. Evidence was strongest for adverse associations of female exposure to polychlorinated biphenyls with TTP, with some additional support for associations of female exposure to polybrominated diphenyl ethers and PFAS with longer TTP. Our review provided little or no support for associations between female exposure to OC pesticides or male exposure to any of the POP groups and TTP.

WIDER IMPLICATIONS

Evidence suggests that female exposure to at least some POPs may reduce fecundability. Although many of these chemicals are no longer in production, they are still detectable in human biosamples because of their persistence in the environment. Replacement chemicals that are being introduced as older ones are restricted may have similar reproductive consequences. Future studies should examine these newer POPs, assess interactions between POPs and other chemical and non-chemical exposures, investigate how POPs are distributed in and metabolised by the human body and focus on populations that may be disproportionately exposed.

Effects of incremental endosulfan sulfate exposure and high fat diet on lipid metabolism, glucose homeostasis and gut microbiota in mice

The influence of pollutants on metabolic diseases such as type 2 diabetes mellitus is an emerging field in environmental medicine. Here, we explored the effects of a low-dose endosulfan sulfate (ES), a major metabolite of the pesticide endosulfan and a bio-persistent contaminant detected in environmental and human samples, on the progress of obesity and metabolic disorders. Pregnant CD-1 mice were given ES from gestational day 6 to postnatal day 21 (short-term). After weaning, male pups of exposed dams were provided with a low-fat or a high-fat diet (LFD or HFD) and assessed after an additional 12 weeks. At the same time, one group of male pups continuously received ES (long-term). Treatment with low-dose ES, short or long-term, alleviated the development of obesity and accumulation of hepatic triglycerides induced by HFD. Analysis of gene expression, metabolic profile and gut microbiome indicates that ES treatment inhibits adipogenesis induced by HFD due to enhanced lipid catabolism, fatty acid oxidation and disturbance of gut microbiota composition. However, impaired glucose and insulin homeostasis were still conserved in HFD-fed mice exposed to ES. Furthermore, ES treatment impaired glucose tolerance, affected hepatic gene expression, fatty acids composition and serum metabolic profile, as well as disturbed gut microbiota in LFD-fed mice. In conclusion, ES treatment at levels close to the accepted daily intake during fetal development directly impact glucose homeostasis, hepatic lipid metabolism, and gut microbiome dependent on the type of diet consumed. These findings provide a better understanding of the complex interactions of environmental pollutants and diet at early life stages also in the context of metabolic disease.

Biomarkers of metabolic disorders and neurobehavioral diseases in a PCB- exposed population: What we learned and the implications for future research

Polychlorinated biphenyls (PCBs) are one of the original twelve classes of toxic chemicals covered by the Stockholm Convention on Persistent Organic Pollutants (POP), an international environmental treaty signed in 2001. PCBs are present in the environment as mixtures of multiple isomers at different degree of chlorination. These compounds are manmade and possess useful industrial properties including extreme longevity under harsh conditions, heat absorbance, and the ability to form an oily liquid at room temperature that is useful for electrical utilities and in other industrial applications. They have been widely used for a wide range of industrial purposes over the decades. Despite a ban in production in 1979 in the US and many other countries, they remain persistent and ubiquitous in environment as contaminants due to their improper disposal. Humans, independent of where they live, are therefore exposed to PCBs, which are routinely found in random surveys of human and animal tissues. The prolonged exposures to PCBs have been associated with the development of different diseases and disorders, and they are classified as endocrine disruptors. Due to its ability to interact with thyroid hormone, metabolism and function, they are thought to be implicated in the global rise of obesity diabetes, and their potential toxicity for neurodevelopment and disorders, an example of gene by environmental interaction (GxE). The current review is primarily intended to summarize the evidence for the association of PCB exposures with increased risks for metabolic dysfunctions and neurobehavioral disorders. In particular, we present evidence of gene expression alterations in PCB-exposed populations to construct the underlying pathways that may lead to those diseases and disorders in course of life. We conclude the review with future perspectives on biomarker-based research to identify susceptible individuals and populations.

Mixture of Organophosphates Chronic Exposure and Pancreatic Dysregulations in Two Different Population Samples

Organophosphates (OP) are a major agrochemical. The application of OP pesticides is expected to increase multifold in the coming decades. The etiology of diabetic diseases is attributed to multiple factors including OP pesticide exposure. The present study investigates pancreatic dysregulation with respect to exocrine enzymes and diabesity in groups of Pakistani and Cameroonian people exposed to a mixture of OP pesticides. Nine hundred and four OP exposed individuals were enrolled for this cross-sectional study after due consent and approval from an ethical review committee. Pesticides' residues were measured by GC-MS spectrometry. Cholinergic enzymes were measured by Elman's method. Serum glucose, insulin, serum amylase, lipase, and triglyceride were measured by spectrophotometry and ELISA; HOMA-IR was determined in OP exposed and non-exposed participants. Stata 15 and R 3.2.0 software were used for statistical analysis of the data. Malathion, chlorpyrifos, and parathion residues were evident in plasma samples. RBC-acetylcholinesterase was significantly depressed in OP exposed groups. In both population samples, investigated pancreatic functions were found to be statistically significantly more dysregulated than non-exposed. OP exposure indicated risk of diabetes and insulin, glycaemia, adiponectin, triglycerides, and TNF-α dysregulations. The study concludes that both OP exposed population groups exhibited a mixture of OP residues and pancreatic dysregulation, although the effect was more pronounced in the Cameroonian population. In addition, serum lipase has a positive correlation with OP exposure and diabetes and may be suggested as an alternate/additional diagnostic marker for diabesity under OP exposure. However, screening of other environmental co-factors with OP for pancreatic dysregulation is suggested.

A Systematic Review of Environmental Health Outcomes in Selected American Indian and Alaska Native Populations

BACKGROUND

Economic and social marginalization among American Indians and Alaska Natives (AI/ANs) results in higher chronic disease prevalence. Potential causal associations between toxic environmental exposures and adverse health outcomes within AI/AN communities are not well understood.

OBJECTIVES

This review examines epidemiological literature on exposure to toxicants and associated adverse health outcomes among AI/AN populations.

METHODS

PubMed, Embase, Cochrane, Environment Complete, Web of Science Plus, DART, and ToxLine were searched for English-language articles. The following data were extracted: lead author's last name, publication year, cohort name, study location, AI/AN tribe, study initiation and conclusion, sample size, primary characteristic, environmental exposure, health outcomes, risk estimates, and covariates.

RESULTS

About 31 articles on three types of environmental exposures met inclusion criteria: persistent organic pollutants (POPs), heavy metals, and open dumpsites. Of these, 17 addressed exposure to POPs, 10 heavy metal exposure, 2 exposure to both POPs and heavy metals, and 2 exposure to open dumpsites. Studies on the Mohawk Nation at Akwesasne; Yupik on St. Lawrence Island, Alaska; Navajo Nation; Gila River Indian Community; Cheyenne River Sioux; 197 Alaska Native villages; and 13 tribes in Arizona, Oklahoma, North Dakota, and South Dakota that participated in the Strong Heart Study support associations between toxicant exposure and various chronic conditions including cardiovascular conditions, reproductive abnormalities, cancer, autoimmune disorders, neurological deficits, and diabetes.

DISCUSSION

The complex interplay of environmental and social factors in disease etiology among AI/ANs is a product of externally imposed environmental exposures, systemic discrimination, and modifiable risk behaviors. The connection between environmental health disparities and adverse health outcomes indicates a need for further study.

Indoor persistent organic pollutants in agricultural areas from Argentina

Persistent Organic Pollutants (POPs) are anthropogenic chemicals extensively used in the past for industrial and agricultural purposes, characterized by their lipophilicity, ubiquity, volatility and environmental persistence. By other hand, chlorpyrifos is the most widely used current pesticide (CUPs) being the main insecticide used for crops in Argentina. The aim of this work was to assess levels of POPs and CUPs in different fractions of airborne particles collected indoor in agricultural areas from Argentina. Particles higher than 2.5 µm were trapped in polyurethane foams (PUF) while particles smaller than 1 µm and volatile compounds were adsorbed on activated charcoal. Compounds were analyzed by gas chromatograph with electron capture detector (GC-ECD). Endosulfans, chlordanes, PCBs, and HCHs were detected in all PUF samples, while endosulfans, chlorpyrifos, PCBs, and HCHs were the most abundant in smaller particles. Majority of pesticides showed higher concentrations during the summer season (1397.7 vs 832.5 pg/m³ ). Even adding up all measured organic compounds, no sample reaches the threshold limit value for indoor pesticides levels (0.1 pg/m³ ), neither in the large or small particle fraction. However, the fact that chronic exposure to POPs has been linked to several diseases raises concern for human health.

A moderate physiological dose of benzyl butyl phthalate exacerbates the high fat diet-induced diabesity in male mice

Exposure to endocrine disrupting chemicals (EDCs) used in plastic manufacturing processes may be contributing to the current increase in metabolic disorders. Here, we determined that benzyl butyl phthalate (BBP), a common EDC and food packaging plasticizer, mixed into chow diet (CD) and high fat diets (HFD) at varying concentrations (4 μg/kg body weight (bw)/day, 169 μg/kg bw/day, 3 mg/kg bw/day, 50 mg/kg bw/day) produced a number of detrimental and sex-specific metabolic effects in C57BL/6 male and female mice after 16 weeks. Male mice exposed to moderate (3 mg/kg bw/day) concentrations of BBP in an HFD were especially affected, with significant increases in body weight due to significant increases in weight of liver and adipose tissue. Other doses did not show any significant changes when compared to only CD or HFD alone. HFD in the presence of 3 mg/kg bw/day BBP showed significant increases in fasting blood glucose, glucose intolerance, and insulin intolerance when compared to HFD alone. Furthermore, this group significantly alters transcriptional regulators involved in hepatic lipid synthesis and its downstream pathway. Interestingly, most of the BBP doses had no phenotypic effect when mixed with CD and compared to CD alone. The female mice did not show a similar response as the male population even though they consumed a similar amount of food. Overall, these data establish a dose which can be used for a BBP-induced metabolic research model and suggest that a moderate dosage level of EDC exposure can contribute to widely ranging metabolic effects.

Serum concentrations of persistent organic pollutants and the metabolic syndrome in Akwesasne Mohawks, a Native American community

The metabolic syndrome (MetS) is a group of diseases that tend to occur together, including diabetes, hypertension, central obesity, cardiovascular disease and hyperlipidemia. Exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) has been associated with increased risk of development of several of the components of the MetS. The goal of this study is to determine whether the associations with POPs are identical for each of the components and for the MetS. The subject population was 601 Native Americans (Akwesasne Mohawks) ages 18 to 84 who answered a questionnaire, were measured for height and weight and provided blood samples for clinical chemistries (serum lipids and fasting glucose) and analysis of 101 PCB congeners and three OCPs [dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and mirex]. Associations between concentrations of total PCBs and pesticides, as well as various PCB congener groups with each of the different components of the MetS were determine so as to ask whether there were similar risk factors for all components of the MetS. After adjustment for other contaminants, diabetes and hypertension were strongly associated with lower chlorinated and mono-ortho PCBs, but not other PCB groups or pesticides. Obesity was most closely associated with highly chlorinated PCBs and was negatively associated with mirex. High serum lipids were most strongly associated with higher chlorinated PCBs and PCBs with multiple ortho-substituted chlorines, as well as total pesticides, DDE and HCB. Cardiovascular disease was not closely associated with levels of any of the measured POPs. While exposure to POPs is associated with increased risk of most of the various diseases comprising the MetS, the specific contaminants associated with risk of the component diseases are not the same.

Association between exposure to persistent organic pollutants and mercury, and glucose metabolism in two Canadian Indigenous populations

BACKGROUND

The body burden of metals and persistent organic pollutants (POPs) is particularly high in populations that rely on fish and other marine species for sustenance. This exposure has been associated with an increased risk of type 2 diabetes, but results remain contrasted.

OBJECTIVE

We studied this association in two Indigenous populations of northern Québec (Canada) with markedly different prevalences of diabetes and levels of exposure to POPs and mercury.

METHODS

As part of health surveys conducted in 2004-2009, diabetes prevalence and glucose metabolism (glucose, insulin, HOMA-IR, HOMA-B) in non-diabetic fasting adults were assessed using similar protocols in two populations: Inuit from Nunavik (n = 877) and Cree from Eeyou Istchee territory (n = 780). Blood mercury, plasma polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides/metabolites and polybrominated diphenylethers (PBDEs) levels were measured in samples collected at the time of examination. Logistic and linear regressions and restricted cubic splines analyses were conducted adjusting for sex, age, waist circumference, smoking and omega-3 fatty acid content in plasma phospholipids.

RESULTS

Diabetes prevalence was higher in Cree (20%) than in Inuit (7%), whereas environmental exposure was 2 to 3-fold greater in Inuit than in Cree participants. In the range of exposure common to the two populations, we observed similar linear increases in the risk of diabetes with increasing contaminant exposure. Among Cree participants, fasting glucose was positively associated with plasma PBDE level, and HOMA-B negatively associated with concentrations of ∑PCBs, dichlorodiphenyldichloroethylene, PBDEs and ∑OC pesticides. Among Inuit participants, a trend towards reduced insulin secretion was observed in association with most contaminants, but the relation was nonlinear (greater reduction at intermediate levels of exposure). A significant increase in fasting glucose levels was observed at elevated blood mercury levels (>16 μg/L).

CONCLUSION

The observed association between POPs exposure and diabetes risk in the two populations studied should be confirmed using prospective design. Our results suggest the need for additional research on the physiopathological process through which POPs exposure may induce type 2 diabetes in these Indigenous populations.

Assessment of a potential PCB exposure among (former) underground miners by hydraulic fluids

Polychlorinated biphenyls (PCBs) were used in technical mixtures of different PCB congeners as hydraulic fluids in underground mining in Germany in North Rhine-Westphalia, Ibbenbueren, and Saarland from the mid-1960s to 1986. Mine workers who were involved in maintenance and repair or operation of hydraulically driven machines in underground mines were potentially exposed to liquids containing PCBs. The aim of the present study was to investigate whether this potential exposure which occurred more than 30 years ago was still detectable. Biomonitoring and a structured work anamnesis were conducted on a representative sample of 210 miners. PCBs in plasma were measured by gas chromatography coupled to mass spectrometry with an LOQ of 0.01 µg/L plasma for all congeners. The primary aim was comparison of the number of exceedances of the underlying comparative values for PCB congeners with those of the general population. Secondary endpoint was the question whether there were regional differences in potential PCB exposure. The biomonitoring showed a significant difference for PCB 74 with N= 94 (45%); for PCB 114 with N = 64 (31%) and for PCB 99 and PCB 105 with N = 23 (11%) and N = 19 (9%) of 210 measurements above the reference value compared to the general population (5%). The all over detection frequencies (µg/L plasma median | SD | min |max) of these congeners were as follows:PCB 74: 0.128 | 0.481 | < LOD | 3.098; PCB 99:0.035 | 0.078 | < LOD | 0.582PCB 105: 0.005 | 0.031 | < LOD | 0.307; PCB 114:0.005 | 0.024 | < LOD | 0.140Regional differences were not detectable.

Associations between the exposure to persistent organic pollutants and type 2 diabetes in East China: A case-control study

Persistent organic pollutants (POPs) have been associated with a high risk of type 2 diabetes in different regions, although few studies from China have been published. We aimed to investigate the associations between POP exposure and type 2 diabetes in Chinese population. A total of 158 participants diagnosed with type 2 diabetes and 158 participants without the disorder from Shandong Province were enrolled in this case-control study during 2016-2017. Nine polychlorinated biphenyl congeners (PCBs) and 2 polybrominated diphenyl ethers with detectable levels in ≥75% of the participants were selected for data analysis. The results showed that POP exposure was significantly and positively associated with the risk of diabetes after adjusting for age, sex, BMI, triglycerides and total cholesterol. However, we did not observe an obvious modified effect of adiposity on the associations between POP exposure and diabetes in the present study, as strong associations between POPs and diabetes were observed in both the higher-BMI (BMI≥25 kg/m²) and the lower-BMI (BMI<25 kg/m²) groups. POPs showed stronger associations with diabetes in males than in females. The odds ratio (OR) for the highest quartile of ∑POPs was 6.97 for males, nearly two times higher than that for females (OR = 3.58). All these findings suggest that POP exposure may impact the risk of diabetes in Chinese population.

Examining environmental contaminant mixtures among adults with type 2 diabetes in the Cree First Nation communities of Eeyou Istchee, Canada

Type 2 diabetes mellitus (T2DM) disproportionately affects Indigenous populations. It is possible that exposure to complex mixtures of environmental contaminants contribute to T2DM development. This study examined the association between complex environmental contaminant mixtures and T2DM among Canadian Indigenous communities from the Eeyou Istchee territory, Quebec, Canada. Using data from the cross-sectional Multi-Community Environment-and-Health Study (2005–2009) Principal Component Analysis (PCA) was used to reduce the dimensionality of the following contaminants: 9-polychlorinated biphenyl congeners; 7-organic pesticides; and 4-metal/metalloids. Following this data reduction technique, we estimated T2DM prevalence ratios (PR) and 95% confidence intervals using modified Poisson regression with robust error variance across derived principal components, adjusting for a priori covariates. For both First Nation adult males (n = 303) and females (n = 419), factor loadings showed dichlorodiphenyltrichloroethane (DDT) and lead (Pb) highly loaded on the second principal component (PC) axis: DDT negatively loaded, and Pb positively loaded. T2DM was significantly associated with PC-2 across all adjusted models. Because PCA produces orthogonal axes, increasing PC-2 scores in the fully adjusted model for females and males showed (PR = 0.84; 95% CI 0.72, 0.98) and (PR = 0.78; 95% CI 0.62, 0.98), respectively. This cross-sectional study suggests that our observed association with T2DM is the result of DDT, and less likely the result of Pb exposure. Further, detectable levels of DDT among individuals may possibly contribute to disease etiology.

A Bayesian assessment of polychlorinated biphenyl contamination of fish communities in the Laurentian Great Lakes

Polychlorinated biphenyl (PCB) contamination has historically posed constraints on the recreational and commercial fishing industry in the Great Lakes. Empirical evidence suggests that PCB contamination represents a greater health risk from fish consumption than other legacy contaminants. The present study attempts a rigorous assessment of the spatio-temporal PCB trends in multiple species across the Canadian waters of the Great Lakes. We applied a Bayesian modelling framework, whereby we initially used dynamic linear models to delineate PCB levels and rates of change, while accounting for the role of fish length and lipid content as covariates. We then implemented Bayesian hierarchical modelling to evaluate the temporal PCB trends during the dreissenid pre- and post-invasion periods, as well as the variability among and within the water bodies of the Great Lakes system. Our analysis indicates that Lake Ontario is characterized by the highest PCB levels among nearly all of the fish species examined. Historically contaminated local areas, designated as Areas of Concern, and embayments receiving riverine inputs displayed higher concentrations within each of the water bodies examined. The general temporal trend across the Great Lakes was that the high PCB concentrations during the early 1970s followed a declining trajectory throughout the late 1980s/early 1990s, likely as a result of the reductions in industrial emissions and other management actions. Nonetheless, after the late 1990s/early 2000s, our analysis provided evidence of a decline in the rate at which PCB concentrations in fish were dropping, accompanied by a gradual establishment of species-specific, steady-state concentrations, around which there is considerable year-to-year variability. The overall trends indicate that reduced contaminant emissions have brought about distinct beneficial changes in fish PCB concentrations, but past historical contamination along with other external or internal stressors (e.g., invasive species, climate change) continue to modulate the current levels, thereby posing potential risks to humans through fish consumption.

The environmental pollutant, polychlorinated biphenyls, and cardiovascular disease: a potential target for antioxidant nanotherapeutics

Despite production having stopped in the 1970s, polychlorinated biphenyls (PCBs) represent persistent organic pollutants that continue to pose a serious human health risk. Exposure to PCBs has been linked to chronic inflammatory diseases, such as cardiovascular disease, type 2 diabetes, obesity, as well as hepatic disorders, endocrine dysfunction, neurological deficits, and many others. This is further complicated by the PCB's strong hydrophobicity, resulting in their ability to accumulate up the food chain and to be stored in fat deposits. This means that completely avoiding exposure is not possible, thus requiring the need to develop intervention strategies that can mitigate disease risks associated with exposure to PCBs. Currently, there is excitement in the use of nutritional compounds as a way of inhibiting the inflammation associated with PCBs, yet the suboptimal delivery and pharmacology of these compounds may not be sufficient in more acute exposures. In this review, we discuss the current state of knowledge of PCB toxicity and some of the antioxidant and anti-inflammatory nanocarrier systems that may be useful as an enhanced treatment modality for reducing PCB toxicity.

Diazinon exposure activated transcriptional factors CCAAT-enhancer-binding proteins α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) and induced adipogenesis in 3T3-L1 preadipocytes

Environmental chemical exposure could be a contributor to the increasing obesity epidemic. Diazinon, an organophosphate insecticide, has been widely used in the agriculture, and exposure of the general population to diazinon has been reported. Diazinon has been known to induce neurotoxic effects mainly through the inhibition of acetylcholinesterase (AChE). However, its association with dysregulation of adipogenesis has been poorly investigated. The current study aimed to examine the mechanism of diazinon's effect on adipogenesis using the 3T3-L1 preadipocytes combined with a single-cell-based high-content analysis. The results showed that diazinon induced lipid droplet accumulation in a dose-dependent manner. The dynamic changes of adipogenic regulatory proteins and genes were examined at the three stages of adipogenesis (induction, differentiation, and maturation) in 3T3-L1 cells treated with various doses of diazinon (0, 1, 10, 100 μM) using real-time quantitative RT-PCR and Western Blot respectively. Diazinon significantly induced protein expression of transcriptional factors CCAAT-enhancer-binding proteins α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ), their downstream proteins, fatty acid synthase (FASN), acetyl CoA carboxylase (ACC), fatty acid-binding protein 4 (FABP4), lipoprotein lipase (LPL), adiponectin and perilipin in dose and time-dependent manners. Similarly, the adipogenic genes were significantly induced in a dose and time-dependent manner compared to the relative controls. The current study demonstrates that diazinon promotes lipid accumulation and activates the adipogenic signaling pathway in the in vitro model.

Elevated Levels of Organochlorine Pesticides in South Asian Immigrants Are Associated With an Increased Risk of Diabetes

OBJECTIVE

Rates of diabetes mellitus are higher in South Asians than in other populations and persist after migration. One unexplored cause may be higher exposure to persistent organic pollutants associated with diabetes in other populations. We compared organochlorine (OC) pesticide concentrations in South Asian immigrants and European whites to determine whether the disease was positively associated with OC pesticides in South Asians.

RESEARCH DESIGN AND METHODS

South Asians of Tamil or Telugu descent (n = 120) and European whites (n = 72) were recruited into the London Life Sciences Population Study cohort. Blood samples as well as biometric, clinical, and survey data were collected. Plasma levels of p,p'-dichlorodiphenyldichloroethylene (DDE), p,p'- dichlorodiphenyltrichloroethane, β-hexachlorohexane (HCH), and polychlorinated biphenyl-118 were analyzed by gas chromatography-mass spectrometry. South Asian cases and controls were categorized by binary exposure (above vs below the 50th percentile) to perform logistic regression.

RESULTS

Tamils had approximately threefold to ninefold higher levels of OC pesticides, and Telugus had ninefold to 30-fold higher levels compared with European whites. The odds of exposure to p,p'-DDE above the 50th percentile was significantly greater in South Asian diabetes cases than in controls (OR: 7.00; 95% CI: 2.22, 22.06). The odds of exposure to β-HCH above the 50th percentile was significantly greater in the Tamil cases than in controls (OR: 9.35; 95% CI: 2.43, 35.97).

CONCLUSIONS

South Asian immigrants have a higher body burden of OC pesticides than European whites. Diabetes mellitus is associated with higher p,p'-DDE and β-HCH concentrations in this population. Additional longitudinal studies of South Asian populations should be performed.

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.

Association of plasma PCB levels and HbA1c concentration in Iran

Background

The rapid increase in prevalence of diabetes mellitus over the last decades warrants more attention to the effects of environmental and occupational exposures on glucose metabolism. Our study aimed to assess the association between the plasma levels of various congeners of polychlorinated biphenyls (PCBs) and the serum concentration of glycated haemoglobin (HbA1c).

Methods

Our study population consisted of 140 Iranian adults from seven different occupational groups and a group of non-occupationally exposed female participants. The plasma concentration of PCBs were determined at the laboratory of occupational toxicology at RWTH Aachen University, Germany. We considered an HbA1c concentration of 5.7% and more as indicating a disturbed glucose metabolism. Logistic regression was used to assess the association between quartiles of concentrations of PCB congeners and serum HbA1c.

Results

Participants with an increased HbA1c value had higher plasma levels of PCB 138, 153, 180 and the PCB sum, although this association was statistically not significant. There was no significant difference between the levels of PCB 138, 153, 180, the sum of these congeners, and PCB 118 in their quartiles when comparing with HbA1c concentrations.

Conclusions

For our cohort, we could not demonstrate a significant association between PCB and HbA1c concentrations indicating a disturbance of glucose metabolism.

Electronic supplementary material

The online version of this article (10.1186/s12995-018-0199-4) contains supplementary material, which is available to authorized users.

The Relationship between Persistent Organic Pollutants Exposure and Type 2 Diabetes among First Nations in Ontario and Manitoba, Canada: A Difference in Difference Analysis

We previously studied the association between fish consumption and prevalence of type 2 diabetes (T2D) in Manitoba and Ontario First Nations (FNs), Canada and found different results. In this study, we used a difference in difference model to analyze the data. Dietary and health data from the First Nations Food Nutrition and Environment Study, a cross-sectional study of 706 Manitoba and 1429 Ontario FNs were analyzed. The consumption of fish was estimated using a food frequency questionnaire. Fish samples were analyzed for dichloro diphenyldichloro ethylene (DDE) and polychlorinated biphenyls (PCBs) content. Difference in difference model results showed that persistent organic pollutant (POP) exposure was positively associated with T2D in a dose-response manner. Stronger positive associations were found among females (OR = 14.96 (3.72-60.11)) than in males (OR = 2.85 (1.14-8.04)). The breakpoints for DDE and PCB intake were 2.11 ng/kg/day and 1.47 ng/kg/day, respectively. Each further 1 ng/kg/day increase in DDE and PCB intake increased the risk of T2D with ORs 2.29 (1.26-4.17) and 1.44 (1.09-1.89), respectively. Our findings suggest that the balance of risk and benefits associated with fish consumption is highly dependent on the regional POP concentrations in fish.

Role of bisphenol A as environmental factor in the promotion of non-alcoholic fatty liver disease: in vitro and clinical study

BACKGROUND

Bisphenol A is an endocrine disrupting chemical associated with type 2 diabetes mellitus (T2DM), cardiovascular disease and liver enzyme abnormalities.

AIM

To evaluate bisphenol A plasma and urine levels in non-alcoholic fatty liver disease (NAFLD) patients compared to healthy subjects. Furthermore, we evaluated, in human HepG2 cells, the effects of exposure to different concentrations of bisphenol A on both oxidative stress induction and cell proliferation.

METHODS

We enrolled 60 patients with histological diagnosis of NAFLD with or without T2DM and sixty healthy subjects. In vitro, the proliferation of bisphenol A-exposed HepG2 cells at two different concentrations (0.025 and 0.05 μM) was evaluated, both at high (H-HepG2) and at low (L-HepG2) glucose concentrations for 48 h. Lipoperoxidation was assessed by thiobarbituric acid reactive substances (TBARS) assay.

RESULTS

Bisphenol A levels were significantly higher in 60 NAFLD subjects, both in urine and in plasma (P < 0.0001) when compared to controls and, in this group, it appeared to be higher in 30 non-alcoholic steatohepatitis patients compared to 30 simple steatosis subjects (P < 0.05), independently from the presence of T2DM. After a bisphenol A-free diet for 1 month, NAFLD patients showed a significant reduction in bisphenol A circulating levels (P < 0.05), without a significant reduction in urine levels. H-HepG2 cells treated with bisphenol A (0.05 μM) increased proliferation compared to controls at 48 h (P < 0.0001). Bisphenol A increased TBARS levels at 48 h versus controls.

CONCLUSIONS

Our study reveals a possible role of bisphenol A as an environmental factor involved in the promotion of NAFLD, particularly in T2DM patients.

Association between diabetes and pesticides: a case-control study among Thai farmers

Background

Pesticides are an agricultural chemical suspected to be a significant contributor to a global diabetes pandemic. The purpose of this study was to confirm previous findings of the link between diabetes and some agricultural pesticides and to identify the particular pesticides that are most likely to pose a risk of diabetes in the community.

Methods

A population-based case-controlled study was conducted among residents in the Bang Rakam district of Phitsanulok Province in Thailand. Lifetime pesticide exposure and other relevant data were collected from 866 participating cases with diabetes mellitus and 1021 healthy controls.

Results

After adjusting for gender, age, BMI, cigarette smoking, alcohol consumption, family history of diabetes, and occupation, it was found that the prevalence of diabetes was positively associated with exposure to all types of pesticides, including insecticides, herbicides, fungicides, rodenticides, and molluscicides, with exposure to rodenticides being statistically significant (OR = 1.35; 95%CI 1.04–1.76). Among 35 individual brand-named pesticides investigated, we found statistically significant ORs with three insecticides, including one organochlorine [endosulfan (OR = 1.40; 95%CI 1.01–1.95)], one organophosphate [mevinphos (OR = 2.22; 95%CI 1.17–4.19)], and one carbamate [carbaryl/Sevin (OR = 1.50; 95%CI 1.02–2.19)]; and one fungicides [benlate (OR = 2.08; 95%CI 1.03–4.20)].

Conclusions

Our results suggest that the occurrence of diabetes among Thai farmer was associated with pesticide exposure. This finding is in line with previous epidemiological and animal studies. Further study using a larger sample size is needed to confirm the relationship and to identify the more toxic compounds.

Persistent Organic Pollutants as Risk Factors for Obesity and Diabetes

PURPOSE OF REVIEW

The rising prevalence of obesity and diabetes cannot be fully explained by known risk factors, such as unhealthy diet, a sedentary lifestyle, and family history. This review summarizes the available studies linking persistent organic pollutants (POPs) to obesity and diabetes and discusses plausible underlying mechanisms.

RECENT FINDINGS

Increasing evidence suggest that POPs may act as obesogens and diabetogens to promote the development of obesity and diabetes and induce metabolic dysfunction. POPs are synthesized chemicals and are used widely in our daily life. These chemicals are resistant to degradation in chemical or biological processes, which enable them to exist in the environment persistently and to be bio-accumulated in animal and human tissue through the food chain. Increasingly, epidemiologic studies suggest a positive association between POPs and risk of developing diabetes. Understanding the relationship of POPs with obesity and diabetes may shed light on preventive strategies for obesity and diabetes.

Adipose Tissue as a Site of Toxin Accumulation

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