Do perfluoroalkyl substances affect metabolic function and plasma lipids?--Analysis of the 2007-2009, Canadian Health Measures Survey (CHMS) Cycle 1

Relationship between per-fluoroalkyl and polyfluoroalkyl substance exposure and insulin resistance in nondiabetic adults: Evidence from NHANES 2003-2018

BACKGROUND

Studies have linked per- and polyfluoroalkyl substances (PFAS) to chronic metabolic diseases. However, the relationship between PFAS exposure and insulin resistance (IR), a key pathophysiological basis of these metabolic diseases, in nondiabetic individuals have yet to be determined.

METHODS

This study analyzed data from 3909 participants (aged ≥20) from the NHANES 2003-2018 to investigate the associations between serum levels of seven PFAS and and IR indicators, including including HOMA-IR, HOMA-β, fasting insulin, QUICKI, and TyG index. Linear and logistic regression models were used, along with a restricted cubic spline to assess dose-response. Weighted quantile sum (WQS) regression and quantile g-computation (qgcomp) models were used to assess the association between mixed PFAS exposure and IR.

RESULTS

Linear regression revealed that elevated exposure to PFOS [β (95 % CI): 0.04 (0.02, 0.06)], PFOA [0.04 (0.01, 0.06)], and Me_PFOSA_AcOH [0.04 (0.02, 0.06)] was associated with a higher TyG index in adults. Notably, Me_PFOSA_AcOH was negatively associated with IR when assessed by HOMA-IR >2.6 [OR (95 % CI): 0.88 (0.79, 0.98)], although this was not supported by linear regression findings. When IR was defined by a TyG index >8.6, exposure to the highest quartiles of PFOS, PFOA, and Me_PFOSA_AcOH was associated with an increased risk of IR by 63 %, 42 %, and 85 %, respectively [1.63 (1.21, 2.20); 1.42 (1.06, 1.92); 1.85 (1.37, 2.50)]. PFOS, PFOA, and Me_PFOSA_AcOH demonstrated a nonlinear dose-response relationship with IR risk. The WQS and qgcomp models revealed significant positive correlations with the TyG index.

CONCLUSION

Mixed PFAS exposure in US nondiabetic adults was positively associated with IR, as indicated by the TyG index, particularly for PFOS, PFOA, and Me_PFOSA_AcOH. Further research is needed to establish causality, and reinforcing environmental risk mitigation strategies to reduce PFAS exposure is recommended.

Association between mixed exposure to per- and polyfluoroalkyl substances and metabolic syndrome in Korean adults: Data from the Korean National environmental health survey cycle 4

AIM

To explore the effect of mixed exposure to per- and polyfluoroalkyl substances (PFAS) on metabolic syndrome (MetS).

METHODS

This cross-sectional study used data from the Korean National Environmental Health Survey Cycle 4 (2018-2020). The serum concentrations of five PFAS (perfluorooctanoic acid [PFOA], perfluorooctanesulfonic acid [PFOS], perfluorohexanesulfonic acid, perfluorononanoic acid [PFNA], and perfluorodecanoic acid [PFDeA]) were measured, and the relative potency factor approach was employed for the mixture of PFAS (Cmix) assessment. MetS was diagnosed if the patient satisfied three of five criteria: central obesity, elevated triglycerides, reduced high-density lipoprotein cholesterol, elevated blood pressure (BP), and elevated glycated hemoglobin (HbA1c). Age, sex, smoking, drinking, and exercise status were considered as covariates. The risk of MetS for single and mixed exposure to PFAS was analyzed using binomial regression and Bayesian kernel machine regression (BKMR).

RESULTS

A total of 2984 (male:female = 1:1.3; age range, 19-80 years) adults were enrolled. The prevalence of MetS was 45.6%. Each PFAS and Cmix levels were higher in participants with MetS than in those without MetS. Cmix increased the risk of elevated BP and HbA1c, and eventually MetS (odds ratio [OR] = 2.00, 95% confidence interval [CI] 1.11-3.60 per log10Cmix; OR = 1.57, 95% CI 1.07-2.31 in the highest quartile of Cmix [Q4] vs. the lowest [Q1]). Sex-specific analyses revealed that the impact of Cmix was valid in females but not in males (Cmix Q4 vs. Q1: OR = 1.01, 95% CI 0.57-1.8 in males; OR = 2.30, 95% CI 1.38-3.84 in females). In the BKMR analysis, mixed exposure to PFAS dose-dependently increased the risk of MetS, particularly in females. Among single exposures, PFNA contributed significantly to the cumulative effect.

CONCLUSION

Mixed exposure to PFAS was associated with a higher risk of MetS in females. Further studies on potential health concerns associated with PFAS mixtures are warranted.

Perfluoroalkyl/Polyfluoroalkyl Substances: Links to Cardiovascular Disease Risk

Conservative estimates by the World Health Organization suggest that at least a quarter of global cardiovascular diseases are attributable to environmental exposures. Associations between air pollution and cardiovascular risk have garnered the most headlines and are strong, but less attention has been paid to other omnipresent toxicants in our ecosystem. Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are man-made chemicals that are extensively used in industrial and consumer products worldwide and in aqueous film-forming foam utilized in firefighting. As such, our exposure to PFAS is essentially ubiquitous. Given the long half-lives of these degradation-resistant chemicals, virtually, all people are carrying a body burden of PFAS. Health concerns related to PFAS are growing such that the National Academies of Sciences, Engineering and Medicine has recommended standards for clinical follow-up of individuals with high PFAS blood levels, including prioritizing screening for dyslipidemia. The link between PFAS and dyslipidemia has been extensively investigated, and evidence for associations is compelling. However, dyslipidemia is not the only cardiovascular risk factor with which PFAS is associated. Here, we review the epidemiological evidence for links between PFAS of concern identified by the National Academies of Sciences, Engineering and Medicine and risk factors for cardiovascular disease, including overweight/obesity, glucose intolerance, hypertension, dyslipidemia, and hyperuricemia. Moreover, we review the potential connections of PFAS with vascular disease and atherosclerosis. While observational data support associations between the National Academies of Sciences, Engineering and Medicine PFAS and selected cardiac risk factors, additional research is needed to establish causation and better understand how exposure to PFAS leads to the development of these conditions.

Association of exposure to multiple perfluoroalkyl and polyfluoroalkyl substances and glucose metabolism in National Health and Nutrition Examination Survey 2017-2018

Objective

To investigate the relationships between perfluoroalkyl and polyfluoroalkyl substances (PFASs) exposure and glucose metabolism indices.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 waves were used. A total of 611 participants with information on serum PFASs (perfluorononanoic acid (PFNA); perfluorooctanoic acid (PFOA); perfluoroundecanoic acid (PFUA); perfluorohexane sulfonic acid (PFHxS); perfluorooctane sulfonates acid (PFOS); perfluorodecanoic acid (PFDeA)), glucose metabolism indices (fasting plasma glucose (FPG), homeostasis model assessment for insulin resistance (HOMA-IR) and insulin) as well as selected covariates were included. We used cluster analysis to categorize the participants into three exposure subgroups and compared glucose metabolism index levels between the subgroups. Least absolute shrinkage and selection operator (LASSO), multiple linear regression analysis and Bayesian kernel machine regression (BKMR) were used to assess the effects of single and mixed PFASs exposures and glucose metabolism.

Results

The cluster analysis results revealed overlapping exposure types among people with higher PFASs exposure. As the level of PFAS exposure increased, FPG level showed an upward linear trend (p < 0.001), whereas insulin levels demonstrated a downward linear trend (p = 0.012). LASSO and multiple linear regression analysis showed that PFNA and FPG had a positive relationship (>50 years-old group: β = 0.059, p < 0.001). PFOA, PFUA, and PFHxS (≤50 years-old group: insulin β = -0.194, p < 0.001, HOMA-IR β = -0.132, p = 0.020) showed negative correlation with HOMA-IR/insulin. PFNA (>50 years-old group: insulin β = 0.191, p = 0.018, HOMA-IR β = 0.220, p = 0.013) showed positive correlation with HOMA-IR/insulin, which was essentially the same as results that obtained for the univariate exposure-response map in the BKMR model. Association of exposure to PFASs on glucose metabolism indices showed positive interactions between PFOS and PFHxS and negative interactions between PFOA and PFNA/PFOS/PFHxS.

Conclusion

Our study provides evidence that positive and negative correlations between PFASs and FPG and HOMA-IR/insulin levels are observed, respectively. Combined effects and interactions between PFASs. Given the higher risk of glucose metabolism associated with elevated levels of PFAS, future studies are needed to explore the potential underlying mechanisms.

Systemic and immunotoxicity induced by topical application of perfluorohexane sulfonic acid (PFHxS) in a murine model

Per- and polyfluoroalkyl substances (PFAS) are a large group of stable synthetic surfactants that are incorporated into numerous products for their water and oil resistance and have been associated with adverse health effects. The present study evaluated the systemic and immunotoxicity of sub-chronic 28- or 10-day dermal exposure of PFHxS (0.625-5% or 15.63-125 mg/kg/dose) in a murine model. Elevated levels of PFHxS were detected in the serum and urine, suggesting that absorption is occurring through the dermal route. Liver weight (% body) significantly increased and spleen weight (% body) significantly decreased with PFHxS exposure, which was supported by histopathological changes. Additionally, PFHxS significantly reduced the humoral immune response and altered immune subsets in the spleen, suggesting immunosuppression. Gene expression changes were observed in the liver, skin, and spleen with genes involved in fatty acid metabolism, necrosis, and inflammation. Immune-cell phenotyping identified significant decreases in B-cells, NK cells, and CD11b+ monocyte/macrophages in the spleen along with increases in CD4+ and CD8+ T-cells, NK cells, and neutrophils in the skin. These findings support dermal PFHxS-induced liver damage and immune suppression. Overall, data support PFHxS absorption through the skin and demonstrate immunotoxicity via this exposure route, suggesting the need for further examination.

An exposome atlas of serum reveals the risk of chronic diseases in the Chinese population

Although adverse environmental exposures are considered a major cause of chronic diseases, current studies provide limited information on real-world chemical exposures and related risks. For this study, we collected serum samples from 5696 healthy people and patients, including those with 12 chronic diseases, in China and completed serum biomonitoring including 267 chemicals via gas and liquid chromatography-tandem mass spectrometry. Seventy-four highly frequently detected exposures were used for exposure characterization and risk analysis. The results show that region is the most critical factor influencing human exposure levels, followed by age. Organochlorine pesticides and perfluoroalkyl substances are associated with multiple chronic diseases, and some of them exceed safe ranges. Multi-exposure models reveal significant risk effects of exposure on hyperlipidemia, metabolic syndrome and hyperuricemia. Overall, this study provides a comprehensive human serum exposome atlas and disease risk information, which can guide subsequent in-depth cause-and-effect studies between environmental exposures and human health.

Association between exposure to per- and polyfluoroalkyl substances and levels of lipid profile based on human studies

Epidemiological evidence suggests that exposure to per- and polyfluoroalkyl substances (PFAS) is associated with lipid profile levels, but with inconsistent conclusions from different studies. The aim of this study was to conduct a meta-analysis of the relationship between PFAS exposure and lipid profile levels based on population-based epidemiological studies. Embase, PubMed, Ovid database, The Cochrane Library and Web of Science database were used to search appropriate studies (before September 6, 2022) on the correlation between PFAS exposure and lipid profile levels. β value, odd ratio (OR) and 95 % confidence intervals (CIs) were extracted from studies. In this study, we found that higher low-density lipoprotein (LDL) levels were associated with exposure to perfluoroundecanoic acid (PFUnDA) (β value=0.13, 95 % CIs: 0.02, 0.24) and perfluorooctane sulfonic acid (PFOS) (β value=0.13, 95 % CIs: 0.04, 0.21). PFOA, PFOS and PFNA exposure were significantly related to the higher levels of total cholesterol (TC) with the pooled effect estimates of 0.08 (95 % CI: 0.02, 0.14), 0.13 (95 % CI: 0.05, 0.21) and 0.14 (95 % CI: 0.08, 0.20) respectively. In sum, our results identified that PFOA, PFOS, PFNA and PFUnDA were the most important risk factors for abnormal levels of lipid profile, indicating that we should prevent cerebrovascular disease by reducing and controlling PFAS exposure.

Association among serum per- and polyfluoroalkyl substances, lipid profile and metabolic syndrome in Czech adults, HBM-EHES survey 2019

OBJECTIVES

Per- and polyfluoroalkyl substances (PFASs) are a large group of persistent synthetic chemicals widely used commercially. They accumulate increasingly in all environmental components and enter the organisms, including humans. Some of them are associated with the risk of harm to health, among others with metabolic disorders. To test the associations between blood serum levels of PFASs and blood lipid profile as well as metabolic syndrome, we linked human biomonitoring with the Czech Health Examination Survey (CZ-EHES) conducted in 2019.

METHODS

A total of 168 participants of the CZ-EHES survey aged 25-64 years were examined including anthropometrical data and analyses for serum PFAS and blood lipid levels. Extended model approach in multiple linear regression models was used for identification of the associations between serum levels of 11 PFASs and lipid profile components. The relation between PFAS serum levels and metabolic syndrome prevalence was tested using a logistic regression model.

RESULTS

Six PFASs were detected over the limit of quantification in at least 40% cases and were examined in subsequent analyses: perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonic acid (PFOS), perfluoroundecanoic acid (PFUdA). The most dominant was PFOS with the mean value amounting to 4.81 ng/ml. After adjusting for potential confounders, we found a significant positive association between serum PFHxS and blood total cholesterol (p = 0.005) as well as LDL-cholesterol (p = 0.008). Significant positive association was also found between PFDA and HDL-cholesterol levels (p = 0.010). No significant associations were detected between PFASs and triglycerides, and between PFASs and metabolic syndrome.

CONCLUSIONS

We found some evidence of a significant association between blood serum PFAS levels and blood cholesterol levels. Our results did not confirm an association between serum PFASs and the metabolic syndrome prevalence.

Cardiometabolic health and per and polyfluoroalkyl substances in an Inuit population

INTRODUCTION

The cardiometabolic health status of Inuit in Nunavik has worsened in the last thirty years. The high concentrations of perfluoroalkyl acids (PFAAs) may be contributing to this since PFAAs have been linked with hypercholesterolemia, diabetes, and high blood pressure. The aim of this study was to examine the association between a PFAAs mixture and lipid profiles, Type II diabetes, prediabetes, and high blood pressure in this Inuit population.

METHODS

We included 1212 participants of the Qanuilirpitaa? 2017 survey aged 16-80 years. Two mixture models (quantile g-computation and Bayesian Kernel Machine Regression (BKMR)) were used to investigate the associations between six PFAAs (PFHxS, PFOS, PFOA and three long-chain PFAAs (PFNA, PFDA and PFUnDA)) with five lipid profiles and three cardiometabolic outcomes. Non-linearity and interaction between PFAAs were further assessed.

RESULTS

An IQR increase in all PFAAs congeners resulted in an increase in total cholesterol (β 0.15, 95% confidence interval (CI) 0.06, 0.24), low-density lipoprotein cholesterol (LDL) (β 0.08, 95% CI 0.01, 0.16), high-density lipoprotein cholesterol (HDL) (β 0.04, 95% CI 0.002, 0.08), apolipoprotein B-100 (β 0.03, 95% CI 0.004, 0.05), and prediabetes (OR 1.80, 95% CI 1.11, 2.91). There was no association between PFAAs and triglycerides, diabetes, or high blood pressure. Long-chain PFAAs congeners were the main contributors driving the associations. Associations were largely linear, and there was no evidence of interaction between the PFAAs congeners.

CONCLUSIONS

Our study provides further evidence of increasing circulating lipids with increased exposure to PFAAs. The increased risk of prediabetes points to the influence of PFAAs on potential clinical outcomes. International regulation of PFAAs is essential to curb PFAAs exposure and related health effects in Arctic communities.

Association of per- and polyfluoroalkyl substance exposure with metabolic syndrome and its components in adults and adolescents

Per- and polyfluoroalkyl substances (PFAS) are widespread contaminants, but few studies have explored the relationship between PFAS and levels of metabolic syndrome (MetS) in the population. The available evidence of an association is also conflicting. We selected adults and adolescents with complete PFAS data from the National Health and Nutrition Examination Survey conducted between 2003 and 2018. We analyzed the association between PFAS and MetS using multivariate logistic regression models and evaluated potential nonlinear relationships with restricted cubic spline models. Additionally, we employed weighted quantile sum (WQS) regressions to uncover the multiple exposure effects and relative weights of each PFAS. Finally, we conducted a series of sensitivity analyses to test the robustness of our findings. In this population-based study, we analyzed data from a total of 4,973 adults, aged 20-85 years, and 1,381 adolescents, aged 12-19 years. Using fully adjusted multivariate logistic regression models, we found that serum levels of perfluorodecanoate (PFDA) [0.65 (0.50, 0.85)] and total PFAS [0.92 (0.85, 0.99)] were negatively associated with the prevalence of MetS in adults. Similarly, in adolescents, we observed negative correlations between the prevalence of MetS and levels of PFDA [0.55 (0.38, 0.80)], perfluorooctanoic acid (PFOA) [0.62 (0.39, 1.00)], perfluorooctane sulfonic acid (PFOS) [0.59 (0.36, 0.96)], and total PFAS [0.61 (0.37, 0.99)]. Additionally, our study identified statistically significant negative associations between serum levels of PFAS and certain components of MetS, primarily elevated fasting glucose and lower high-density lipoprotein cholesterol. Our study found that PFAS was associated with a lower prevalence of MetS in both adults and adolescents, offering new insights into the relationship between PFAS and metabolic health. Interestingly, however, we observed conflicting findings across the components of MetS. Specifically, we observed that PFAS had a negative correlation with some metrics and a positive correlation with others. These conflicting results point to a complex interplay between PFAS and various metrics of metabolic health.

Association of per- and polyfluoroalkyl substances with hepatic steatosis and metabolic dysfunction-associated fatty liver disease among patients with acute coronary syndrome

Etiology of hepatic steatosis and metabolic dysfunction-associated fatty liver disease (MAFLD) among acute coronary syndrome (ACS) remains unclear. Existing studies suggested the potential role of per- and polyfluoroalkyl substances (PFAS) in comorbidity of hepatic steatosis among ACS patients. Therefore, we conducted a cross-sectional study based on the ACS inpatients to assess the associations of plasma PFAS congeners and mixtures with hepatic steatosis and MAFLD. This study included 546 newly diagnosed ACS patients. Twelve PFAS were quantified using ultra-high-performance liquid chromatography-tandem mass spectrometry. Hepatic steatosis was defined by hepatic steatosis index (HSI). MAFLD was defined as the combination of hepatic steatosis based on the risk factor calculation with metabolic abnormalities. Generalized linear model was used to examine the associations of PFAS congeners with HSI and MAFLD. Adaptive elastic net (AENET) was further used for PFAS congeners selection. Mixture effects were also assessed with Bayesian kernel machine regression model (BKMR). Congeners analysis observed significant greater percent change of HSI for each doubling in PFOS (1.82%, 95% CI: 0.87%, 2.77%), PFHxS (1.17%, 95% CI: 0.46%, 1.89%) and total PFAS (1.84%, 95% CI: 0.56%, 3.14%). Moreover, each doubling in PFOS (OR=1.42, 95% CI: 1.13, 1.81), PFHxS (OR=1.31, 95% CI: 1.09, 1.59) and total PFAS (OR=1.43, 95% CI: 1.06, 1.94) was associated with increased risk of MAFLD. In AENET regression, only PFOS presented significant positive associations with HSI. Mixture analysis indicated significant positive associations between PFAS mixtures and HSI. This is the first study to demonstrate associations of PFAS congeners and mixtures with hepatic steatosis and MAFLD among ACS patients, which provides hypothesis into the mechanisms behind comorbidity of hepatic steatosis among ACS patients, as well as tertiary prevention of ACS.

The Hidden Threat: Endocrine Disruptors and Their Impact on Insulin Resistance

The association between Insulin resistance, a global health issue, and endocrine disruptors (EDCs), chemicals interfering with the endocrine system, has sparked concern in the scientific community. This article provides a comprehensive review of the existing literature regarding the intricate relationship between EDCs and insulin resistance. Phthalates, commonly found in consumer products, are well-established EDCs with documented effects on insulin-signaling pathways and metabolic processes. Epidemiological studies have connected phthalate exposure to an increased risk of type 2 diabetes mellitus (T2DM). Perfluoroalkyl substances (PFAS), persistent synthetic compounds, have shown inconsistent associations with T2DM in epidemiological research. However, studies suggest that PFAS may influence insulin resistance and overall metabolic health, with varying effects depending on specific PFAS molecules and study populations. Bisphenol A (BPA), found in plastics and resins, has emerged as a concern for glucose regulation and insulin resistance. Research has linked BPA exposure to T2DM, altered insulin release, obesity, and changes in the mass and function of insulin-secreting β-cells. Triclosan, an antibacterial agent in personal care products, exhibits gender-specific associations with T2DM risk. It may impact gut microbiota, thyroid hormones, obesity, and inflammation, raising concerns about its effects on metabolic health. Furthermore, environmental EDCs like polycyclic aromatic hydrocarbons, pesticides, and heavy metals have demonstrated associations with T2DM, insulin resistance, hypertension, and obesity. Occupational exposure to specific pesticides and heavy metals has been linked to metabolic abnormalities.

Associations between per- and polyfluoroalkyl substances (PFAS) and diabetes in two population-based cohort studies from Sweden

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) have been suggested to contribute to the development of metabolic diseases such as obesity, diabetes and non-alcoholic fatty liver disease (NAFLD). However, evidence from epidemiological studies remain divergent. The aim of the present study was to evaluate associations between PFAS exposure and prevalent diabetes in a cross-sectional analysis and fasting glucose in a longitudinal analysis.

METHODS

In 2373 subjects aged 45-75 years from the EpiHealth study, three PFAS; perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were analyzed in plasma together with information on prevalent diabetes. Participants in the PIVUS study (n = 1016 at baseline, all aged 70 years) were followed over 10 years regarding changes in plasma levels of six PFAS; PFHxS, PFOA, PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), and changes in plasma levels of fasting glucose.

RESULTS

In the EpiHealth study, no overall associations could be observed between the levels of PFOA, PFOS or PFHxS and prevalent diabetes. However, there was a significant sex-interaction for PFOA (p = 0.02), and an inverse association could be seen between PFOA (on a SD-scale) and prevalent diabetes in women only (OR: 0.71, 95% CI: 0.52, 0.96, p-value: 0.02). This association showed a non-monotonic dose-response curve. In the PIVUS study, inverse relationships could be observed between the changes in levels (ln-transformed) of PFOA and PFUnDA vs the change in fasting glucose levels (ln-transformed) over 10 years (p = 0.04 and p = 0.02, respectively). As in EpiHealth, these inverse associations were significant only in women (PFOA: β: -0.03, p = 0.02, PFUnDA: β: -0.03, p = 0.03).

IMPACT

Exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to unfavorable human health, including metabolic disorders such as obesity, diabetes and non-alcoholic fatty liver disease. However, results from in vivo, in vitro and epidemiological studies are incoherent. The aim of the present study was therefore to investigate associations between PFAS and diabetes in a cross-sectional study and glucose levels in a longitudinal study. Results show inverse associations in women only. Results also display non-monotonic dose response curves (i.e., that only low levels of PFOA are related to higher probability of prevalent diabetes). This suggests that sex differences and complex molecular mechanisms may underlie the observed findings. A better understanding of the factors and molecular mechanisms contributing to such differences is recognized as an important direction for future research.

CONCLUSIONS

PFOA was found to be inversely related to both prevalent diabetes and changes in plasma glucose levels among women only. Thus, our findings suggest there are sex differences in the inverse relationship of PFOA and type 2 diabetes and glucose levels.

Per- and Polyfluoroalkyl Substances (PFAS) and Lipid Trajectories in Women 45-56 Years of Age: The Study of Women's Health Across the Nation

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are associated with less favorable blood lipid profiles in epidemiological studies. However, little is known about the potential role of PFAS in longitudinal changes in lipids among midlife women even though women become more susceptible to metabolic alterations during the menopausal transition.

OBJECTIVES

To examine associations of serum PFAS concentrations with longitudinal trajectories of blood total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides in midlife women undergoing menopausal transition.

METHODS

The sample included 1,130 women from the Study of Women's Health Across the Nation 45-56 y of age at baseline (1999-2000). We measured serum PFAS concentrations including linear perfluorooctanoic acid (n-PFOA), perfluorononanoic acid (PFNA), linear and branched perfluorooctanesulfonic acid (n-PFOS and Sm-PFOS, respectively), and perfluorohexanesulfonic acid (PFHxS) at baseline. We used k-means clustering to identify subgroups with different patterns of PFAS mixture. Blood lipids were measured annually or biannually through 2016 with an average follow-up of 14.8 y. We identified longitudinal trajectories of each lipid using latent class growth models. We used multinomial log-linear models adjusted for covariates to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of lipid trajectory classes by PFAS and their mixtures.

RESULTS

Three distinct trajectories (low, middle, high) of total, LDL, and HDL cholesterol and two distinct trajectories (low and high) of triglycerides were identified. n-PFOS, Sm-PFOS, and PFHxS were positively associated with total and LDL cholesterol trajectories. n-PFOS was inversely associated with triglycerides trajectories. PFAS mixtures (high vs. low) showed positive associations with total and LDL cholesterol trajectories (high vs. low), showing ORs (95% CIs) of 1.69 (95% CI: 1.36, 2.12) and 1.79 (95% CI: 1.44, 2.22), respectively.

DISCUSSION

Concentrations of serum PFAS were positively associated with trajectories of total and LDL cholesterol, providing a line of evidence supporting adverse effects of PFAS on lipid homeostasis. https://doi.org/10.1289/EHP12351.

Associations between Per- and Polyfluoroalkyl Substances Exposures and Blood Lipid Levels among Adults-A Meta-Analysis

BACKGROUND

Associations between per- and polyfluoroalkyl substances (PFAS) and blood lipid levels in humans were mixed.

OBJECTIVES

The objective of this meta-analysis was to summarize associations between PFAS and blood lipids in adults.

METHODS

A literature search was conducted on PubMed and Web of Science for articles published through 13 May 2022 that examined associations between PFAS and blood lipids, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triacylglycerols (TGs). Inclusion criteria included the presence of associations between five PFAS (PFOA, PFOS, PFHxS, PFDA, and PFNA) and four blood lipid measures (TC, HDL-C, LDL-C, and TGs) in adults. Data on study characteristics and PFAS-lipid associations were extracted. Assessments of individual study quality were performed. Associations of changes of blood lipid levels corresponding to 1 interquartile range (IQR)-unit increase of blood PFAS levels were pooled using random effects models. Dose-response relationships were examined.

RESULTS

Twenty-nine publications were included in the present analyses. Every IQR increase of PFOA was significantly associated with a 2.1 -mg / dL increase in TC (95% CI: 1.2, 3.0), a 1.3 -mg / dL increase in TGs (95% CI: 0.1, 2.4), and a 1.4 -mg / dL increase in LDL-C (95% CI: 0.6, 2.2). PFOS was also significantly associated with TC and LDL-C levels, and the corresponding values were 2.6 (95% CI: 1.5, 3.6) and 1.9 (95% CI: 0.9, 3.0), respectively. Associations of PFOS and PFOA with HDL-C levels were largely null. For minor PFAS species, PFHxS was significantly associated with higher levels of HDL-C [0.8 (95% CI: 0.5, 1.2)]. Inverse associations were observed between PFDA and TGs [- 5.0 (95% CI: - 8.1 , - 1.9 )] and between PFNA and TGs [- 1.7 (95% CI: - 3.5 , - 0.02 )], whereas a positive association was observed between PFDA and HDL-C [1.4 (95% CI: 0.1, 2.7)]. Nonsignificant nonlinear dose-response relationships were identified for associations of PFOA and PFOS with certain blood lipids.

DISCUSSION

PFOA and PFOS were significantly associated with TC and LDL-C levels in adults. Whether these findings may translate into an elevated cardiovascular disease risk associated with PFAS exposure warrants further investigation. https://doi.org/10.1289/EHP11840.

Evaluation of the research trends on perfluorinated compounds using bibliometric analysis: knowledge gap and future perspectives

Detection of perfluorinated compounds (PFCs) in the environment has been a global concern because of the risk they pose due to their endocrine-disruptive properties. This study analyzed the global trends and research productivity of PFCs from 1990 to 2021. A total number of 3256 articles on PFCs were retrieved from the Web of Science focusing on different environmental and biological matrices. An increase in the productivity of research on PFCs was observed during the survey period which indicates that more research and publications on this class of contaminants are expected in the future. Evaluating the most productive countries and the number of citations per country on PFCs research shows that China and the United States of America were ranked in first and second places. It was also observed that research on PFCs received the most attention from scientists in developed countries, with little research emerging from Africa. Hence, research on PFCs in developing countries, especially low-income countries should be promoted. Consequently, more research programs should be implemented to investigate PFCs in countries and regions where research on these contaminants is low. The study will help researchers, government agencies and policymakers to tailor future research, allocation of funds to PFCs research and countries' collaboration.

Perfluoroalkyl substances and lipid concentrations in the blood: A systematic review of epidemiological studies

BACKGROUND

Perfluoroalkyl substances (PFAS) are widely used synthetic aliphatic compounds. This systematic review aims to assess PFAS associations with low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol (TC) and total triglyceride (TG) concentrations in human populations.

METHOD

We systematically searched four online databases, PubMed, Scopus, Embase, and Cochrane Library for relevant peer-reviewed English language articles published until July 2021. Additional relevant articles identified were also included in the search results. We categorised populations into adults (≥18 years old) and children. Primary findings were the associations between PFAS concentrations and LDL, HDL, TC, and TG concentrations in the serum, plasma, or whole blood; secondary findings were the associations between PFAS concentrations and the odds of lipid-related health outcomes. Quantitative synthesis was done by vote counting of the effect directions between concentrations of PFAS and lipids/health outcomes, repeated on articles with sample size >1000. Sign tests were performed to assess the statistical significance of the differences between positive and negative associations. Sensitivity analysis was performed by separating out articles with populations having high concentrations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Quality was assessed with the STROBE checklist and NHBLI Study Quality Assessment Tool.

RESULTS

A total of 58 articles were included for review. There was evidence that PFAS exposure is associated with higher concentrations of LDL, HDL, and TC, particularly for PFOA-LDL, PFOA-TC, PFOS-TC, and PFNA-LDL. Associations between PFAS and TG tended to be negative, especially for perfluoroundecanoic acid (PFUnDA). Associations between PFAS concentration and the odds of secondary outcomes generally supported a positive association between PFAS and cholesterol concentrations.

CONCLUSION

We found evidence of associations between the concentrations of some PFAS-lipid pairs in human populations. Future research should be conducted on the less well-studied PFAS to explore their effects on human health and in regions where such studies are currently lacking. (300 words).

Associations between Per- and Polyfluoroalkyl Substances (PFAS) and Cardiometabolic Biomarkers in Adults of Czechia: The Kardiovize Study

Even though there is evidence of decreasing trends of per- and polyfluoroalkyl substances (PFAS) in Czechia, there are still major sources of PFAS pollution. Regarding the still-inconsistent results of the relationship between cardiometabolic health and PFAS, the present study sought to determine the association between PFAS levels and the presence of cardiometabolic biomarkers, including blood pressure and dysglycemia drivers in the Czech population. A cross-sectional study with 479 subjects (56.4% women, median: 53 years, range: 25-89) was conducted. Four PFAS were measured in serum: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluorooctane sulfonate (PFOS). The associations between natural log (ln)-transformed PFAS and cardiometabolic biomarkers were assessed through generalized additive models using linear regression and smoothing thin plate splines, adjusted for potential confounders. There were positive and significant (p < 0.05) associations between the ln-transformed PFOA and glucose (β = 0.01), systolic (β = 0.76) and diastolic blood pressure (β = 0.65); total cholesterol (β = 0.07) and LDL-c (β = 0.04); and PFOS with glucose (β = 0.03), BMI (β = 2.26), waist circumference (β = 7.89), systolic blood pressure (β = 1.18), total cholesterol (β = 0.13), and HDL-c (β = 0.04). When significant, the correlations of PFNA and PFDA were negative. Of the four PFAS, only PFOA and PFOS showed a positive association, even in serum levels not as high as the values from the literature.

Perfluorinated compounds in adults and their association with fasting glucose and incident diabetes: a prospective cohort study

BACKGROUND

The endocrine disruption of perfluorinated compounds is an emerging issue. We aimed to examine the association of serum perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) levels with incident diabetes and fasting serum glucose concentration.

METHODS

This prospective cohort study was based on an urban-based cohort subpopulation from the Korean Genome and Epidemiology Study. Serum samples (600 µL) were received from 100 participants in the normoglycemic baseline survey (2004-2013), and concentrations of PFOA and PFOS were measured using mass spectrometry. The incidence of diabetes was tracked in the follow-up survey (2012-2016).

RESULTS

The mean age was 56.4 years (men, 59%). The median serum PFOA and PFOS concentrations were 4.29 ng/mL and 9.44 ng/mL, respectively. PFOA and PFOS concentrations differed according to age, sex, and residential area. After 60 months, 23 patients had diabetes. Log-transformed PFOA (lnPFOA) and log-transformed PFOS (lnPFOS) were significantly higher in those who transitioned to diabetes than in those who did not (both p < 0.05). After multivariate adjustment, lnPFOA (coefficient = 6.98, 95% CI -0.04-14, p = 0.054) and lnPFOS (coefficient = 7.06, 95% CI -0.96-15.08, p = 0.088) predicted increased fasting glucose without statistical significance. In addition, lnPFOA, but not lnPFOS, significantly predicted incident diabetes (HR = 3.98, 95% CI 1.42-11.1, p < 0.01).

CONCLUSION

Exposure to PFOA and PFOS may have a potential dysglycemic effect. In particular, exposure to PFOA increased the risk of diabetes. Further research with larger sample size is warranted.

Lipoprotein profiles associated with exposure to poly- and perfluoroalkyl substances (PFASs) in the EuroMix human biomonitoring study

Exposure to per- and polyfluoroalkyl substances (PFASs) is associated with increased blood cholesterol. Although elevated cholesterol is a well-established risk factor for cardiovascular diseases (CVD), it is not clear whether PFASs affect this risk. Lipoprotein subclasses are emerging biomarkers for disease risk and lipoprotein profiling may provide an insight to physiological implications of PFAS exposure. We explored the association between serum PFAS concentrations and lipoprotein subclasses in a cross-sectional study. We determined the concentrations and lipid composition of the major subclasses of lipoproteins in plasma samples from 127 adult participants of the EuroMix human biomonitoring study by nuclear magnetic resonance (NMR). Serum concentrations of 17 PFASs showed a detection frequency between 30 and 100% and were included in further analyses. We examined the associations between PFAS concentrations and lipoprotein subclasses by linear mixed-effect regression models, adjusted for confounders. In the adjusted models, positive associations were found between several PFASs and cholesterol concentrations in large to medium sized HDL and medium sized LDL particles. We found a 4-12% increase in HDL cholesterol per interquartile range (IQR) increase for several PFASs. In women the associations with PFNA, PFUnDA, PFDoDA and PFOS were significant after adjustment for multiple comparisons. Similar magnitude of change was observed between longer chained PFASs and LDL cholesterol, and a few of these associations reached significance for cholesterol in large to medium LDL particle sizes in women. No significant associations with plasma triglycerides were observed. However, most PFASs tended to be associated with reduction in VLDL (very low-density lipoproteins) particle number and VLDL triglyceride. Findings from this exploratory study, suggest that background PFAS exposures influence particle size distributions and lipid composition of plasma lipoprotein subclasses, and that these effects may be more prominent in women. A two-points lipoprofiling for all subjects indicated both low intra-individual variability and good analytical reproducibility.

Exposure to per- and polyfluoroalkyl substances (PFAS) and type 2 diabetes risk

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous man-made chemicals found in consumer products including fabrics, food packaging, non-stick coatings, and aqueous film-forming foams. PFAS are stable and extremely resistant to degradation, resulting in high persistence throughout the environment as well as in human blood. PFAS consist of a large family of synthetic chemicals, with over 4000 distinct varieties having been identified and around 250 currently being manufactured at globally relevant levels. Numerous epidemiological studies have linked exposure to PFAS with adverse health effects ranging from immunotoxicity, cardiometabolic disease, developmental and reproductive effects, cancer, and recently type 2 diabetes. Several studies have demonstrated associations between serum PFAS concentrations and glycemic indicators of type 2 diabetes including glucose, insulin, and HOMA-IR in adolescent and adult cohorts. In addition, some studies have shown positive associations with incident type 2 diabetes and multiple PFAS. However, the link between PFAS exposure and the development of diabetes continues to be a disputed area of study, with conflicting data having been reported from various epidemiological studies. In this mini review we will summarize the current state of the literature linking PFAS to type 2 diabetes and discuss important future directions including the use of more complex mixtures-based statistical analyses.

Serum per- and polyfluoroalkyl substance concentrations in four municipal US fire departments

BACKGROUND

Firefighters have occupational and environmental exposures to per- and polyfluoroalkyl substances (PFAS). The goal of this study was to compare serum PFAS concentrations across multiple United States fire departments to National Health and Nutrition Examination Survey (NHANES) participants.

METHODS

Nine serum PFAS were compared in 290 firefighters from four municipal fire departments (coded A-D) and three NHANES participants matched to each firefighter on sex, ethnicity, age, and PFAS collection year. Only Departments A and C had sufficient women study participants (25 and six, respectively) to compare with NHANES.

RESULTS

In male firefighters compared with NHANES, geometric mean perfluorohexane sulfonate (PFHxS) was elevated in Departments A-C, sum of branched perfluoromethylheptane sulfonate isomers (Sm-PFOS) was elevated in all four departments, linear perfluorooctane sulfonate (n-PFOS) was elevated in Departments B and C, linear perfluorooctanoate (n-PFOA) was elevated in Departments B-D, and perfluorononanoate (PFNA) was elevated in Departments B-D, but lower in A. In male firefighters compared with NHANES, perfluoroundecanoate (PFUnDA) was more frequently detected in Departments B and D, and 2-(N-methyl-perfluorooctane sulfonamido) acetate (MeFOSAA) was less frequently detected in Departments B-D. In female firefighters compared with NHANES, PFHxS and Sm-PFOS concentrations were elevated in Departments A and C. Other PFAS concentrations were elevated and/or reduced in only one department or not significantly different from NHANES in any department.

CONCLUSIONS

Serum PFHxS, Sm-PFOS, n-PFOS, n-PFOA, and PFNA concentrations were increased in at least two of four fire departments in comparison to NHANES.

Per-/polyfluoroalkyl substance concentrations in human serum and their associations with immune markers of rheumatoid arthritis

Per-/polyfluoroalkyl substances (PFASs) are ubiquitous in the environment and have been proved to be immunotoxic to humans. However, it remains unclear whether exposure to PFASs affects the risk of rheumatoid arthritis (RA). In this study, nine PFASs were determined in human serum collected from 280 health populations and 294 RA patients in a cohort enrolled between 2018 and 2020 in Hangzhou, China, and were examined their correlations with immune marker levels. Perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) were the predominant PFASs in human serum, with median (mean) concentrations of 5.4 (7.6), 2.8 (3.5), and 1.9 (2.5) ng/mL, respectively. Serum PFOA and 6:2 Cl-PFESA concentrations were positively correlated with anti-cyclic citrullinated peptide antibody (ACPA) (β_PFOA = 0.59, 95% confidence interval (CI): 0.37, 0.81; β_{6:2 Cl-PFESA} = 0.48, 95% CI: 0.29, 0.66), immunoglobulin G (β_PFOA = 0.25, 95% CI: 0.21, 0.29; β_{6:2 Cl-PFESA} = 0.16, 95% CI: 0.12, 0.19) as well as rheumatoid factors (RF) (β_PFOA = 0.57, 95% CI: 0.34, 0.80; β_{6:2 Cl-PFESA} = 0.54, 95% CI: 0.36, 0.72). The correlations between serum PFOS levels and RF (β = 0.52, 95% CI: 0.28, 0.77), ACPA (β = 0.48, 95% CI: 0.23, 0.73), as well as immunoglobulin M (β = -0.24, 95% CI: 0.64, 0.15) respectively were statistically stronger. We also found PFOA concentrations in serum were associated with the level of C-reactive protein (β = 0.52, 95% CI: 0.40, 0.65). To our knowledge, this is the first study reporting significant associations between several PFASs and change of specific immune marker levels, suggesting that PFAS exposure may increase the risk of RA in adults.

To which extent are per-and poly-fluorinated substances associated to metabolic syndrome?

Exposure to per- and polyfluoroalkyl substances (PFAS), ubiquitous persistent environmental contaminants, has led to substantial global concern due to their potential environmental and human health effects. Several epidemiological studies have assessed the possible association between PFAS exposure and risk of metabolic syndrome (MetS), however, the results are ambiguous. The aim of this study was to assess the current human epidemiologic evidence on the association between exposure to PFAS and MetS. We performed a systematic search strategy using three electronic databases (PubMed, Scopus, and Web of Science) for relevant studies concerning the associations of PFAS with MetS and its clinical relevance from inception until January 2021. We undertook meta-analyses where there were five or more studies with exposure and outcomes assessments that were reasonably comparable. The pooled odd ratios (ORs) were calculated using random effects models and heterogeneity among studies was assessed by I2 index and Q test. A total of 12 cross-sectional studies (10 studies on the general population and two studies in the occupational settings) investigated the association between PFAS exposure and MetS. We pooled data from seven studies on the general population for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) and five studies for perfluorohexanesulfonate (PFHxS) and perfluorononanoic acid (PFNA). Predominately, most studies reported no statistically significant association between concentrations of PFAS and MetS. In the meta-analysis, the overall measure of effect was not statistically significant, showing no evidence of an association between concentrations of PFOA, PFOS, PFNA, and PFHxS and the risk of MetS. Based on the results of the meta-analysis, current small body of evidence does not support association between PFAS and MetS. However, due to limited number of studies and substantial heterogeneity, results should be interpreted with caution. Further scrutinizing cohort studies are needed to evaluate the association between various and less well-known PFAS substances and their mixture with MetS and its components in both adults and children in different settings.

The association between blood PFAS concentrations and clinical biochemical measures of organ function and metabolism in participants of the Canadian Health Measures Survey (CHMS)

Per- and poly-fluoroalkyl substances (PFAS) are ubiquitous and may persist in human tissue for several years. Only a small proportion of PFAS have been studied for human health effects. We tested the association between human blood levels of six PFAS and several clinical measures of organ and metabolic function in a nationally representative sample of 6768 participants aged 3-79 years old who participated in the Canadian Health Measures Survey. Cross-sectional associations were assessed by generalized linear mixed models incorporating survey-specific sampling weights. An increase in perfluorooctanoic acid (PFOA) equivalent to the magnitude of its geometric mean (GM) of 2.0 μg/L was associated with percentage (95% CI) increases in serum enzymes reflecting liver function: aspartate aminotransferase (AST) 3.7 (1.1, 6.4), gamma-glutamyl transferase (GGT) 11.8 (2.5, 21.8), alanine aminotransferase (ALT) 3.2 (0.5, 5.9), and bilirubin 3.6 (2.7, 4.5). A GM increase in perfluorodecanoic acid (PFDA) of 0.2 μg/L was positively associated with percentage increases in GGT, triglycerides, low-density lipoprotein (LDL) cholesterol, total cholesterol, and calcium with respective increases of 15.5 (2.2, 30.4), 7.0 (1.0, 13.2), 10.7 (5.5, 16.1), 2.8 (0.2, 5.3), and 0.8 (0.3, 1.3). PFOA, perfluorooctane sulfonate (PFOS), PFDA and perfluorononanoic acid (PFNA) were positively associated with GGT. All six congeners were positively associated with at least one biomarker of lipid metabolism, and 5 of 6, PFOA, PFOS, PFDA, perfluorohexane sulfonate (PFHxS) and PFNA were positively associated with serum calcium. Exposure to selected PFAS is associated with clinical blood tests reflecting metabolism and the function of several organ systems. These relatively small changes may possibly indicate early pathology that is clinically inapparent and may possibly be of significance in a general population or in individuals exposed to very high levels of PFAS.

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.

Per-/polyfluoroalkyl substance concentrations in human serum and their associations with liver cancer

Per-/polyfluoroalkyl substances (PFASs) are widespread in global human blood, and have some toxic effects on liver. However, effects of PFAS exposure on human liver cancer (LC) risk are still not known. In this study, 203 LC patients and 203 controls were recruited, and their serum samples were collected between 2019 and 2021. We determined the residues of 12 PFASs in serum from all participants and quantified their association with LC incidence and tumor markers. PFOS (9.8 ng/mL) had the highest mean concentration in human serum, followed by PFOA (8.3 ng/mL) and 6:2 Cl-PFESA (3.9 ng/mL). We found that concentrations of PFOS and 6:2 Cl-PFESA in human serum were significantly correlated with the levels of alpha fetoprotein (AFP) (β_PFOS = 0.13, 95% confidence interval (CI_PFOS): 0.088, 0.17; β_{6:2 Cl-PFESA} = 0.070, CI_{6:2 Cl-PFESA}: 0.036, 0.10). A positive association of PFOS and 6:2 Cl-PFESA with odds ratios (OR) of LC (OR_PFOS = 0.609, CI_PFOS: 1.179, 4.029, P = 0.001; OR_{6:2 Cl-PFESA} = 1.844, CI_{6:2 Cl-PFESA}: 1.176, 2.512, P = 0.02) were found, after adjusting for different covariates. Moreover, serum PFOA concentrations were associated with carcinoembryonic antigen (CEA), but their correlation with the LC incidence was not statistically significant. This new finding supports the evidence for the positive associations among PFAS exposure, change of specific tumor marker, and LC risks.

Characterization of PFOS toxicity on in-vivo and ex-vivo mouse pancreatic islets

Considerable human data have shown that the exposure to perfluorooctane sulfonate (PFOS) correlates to the risk of metabolic diseases, however the underlying effects are not clearly elucidated. In this study, we investigated the impacts of PFOS treatment, using in-vivo, ex-vivo and in-vitro approaches, on pancreatic β-cell functions. Mice were oral-gavage with 1 and 5 μg PFOS/g body weight/day for 21 days. The animals showed a significant increase in liver triglycerides, accompanied by a reduction of triglycerides in blood sera and glycogen in livers and muscles. Histological examination of pancreases showed no noticeable changes in the size and number of islets from the control and treatment groups. Immunohistochemistry showed a reduction of staining intensities of insulin and the transcriptional factors (Pdx-1, islet-1) in islets of pancreatic sections from PFOS-treated groups, but no changes in the intensity of Glut2 and glucagon were noted. Transcriptomic study of isolated pancreatic islets treated ex vivo with 1 μM and 10 μM PFOS for 24 h, underlined perturbations of the insulin signaling pathways. Western blot analysis of ex-vivo PFOS-treated islets revealed a significant reduction in the expression levels of the insulin receptor, the IGF1 receptor-β, Pdk1-Akt-mTOR pathways, and Pdx-1. Using the mouse β-cells (Min-6) treated with 1 μM and 10 μM PFOS for 24 h, Western blot analysis consistently showed the PFOS-treatment inhibited Akt-pathway and reduced cellular insulin contents. Moreover, functional studies revealed the inhibitory effects of PFOS on glucose-stimulated insulin-secretion (GSIS) and the rate of ATP production. Our data support the perturbing effects of PFOS on animal metabolism and demonstrate the underlying molecular targets to impair β-cell functions.

Exposure to novel and legacy per- and polyfluoroalkyl substances (PFASs) and associations with type 2 diabetes: A case-control study in East China

Associations between per- and polyfluoroalkyl substances (PFASs) and the incidence of type 2 diabetes are controversial in epidemiological studies. In addition, limited data are available for assessing the health effects of novel PFAS alternatives. Our study evaluated the effects of PFAS exposure on type 2 diabetes by estimating the associations of PFASs in human serum with the risk of type 2 diabetes and levels of glycemic biomarkers and lipid fractions. The case-control study consisted of 304 participants from Shandong Province, East China, half of which were diagnosed with type 2 diabetes. Logistic regression showed that most PFASs were inversely associated with the risk of type 2 diabetes after adjusting for age, sex, and body mass index. However, concentrations of perfluorooctanoic acid (PFOA) in the control group were positively associated with fasting plasma glucose levels (β = 0.04, 95% confidence interval (CI): 0.0003, 0.08), which may promote the development of type 2 diabetes. Furthermore, each log-unit increase in the concentrations of perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUnDA), and 6:2 chlorinated polyfluoroalkyl ether sulfonic acid (Cl-PFESA) were associated with a total cholesterol increase (i.e., 17.49% (95% CI: 0.93%, 34.90%), 17.49% (95% CI: 4.71%, 31.83%), and 17.49% (95% CI: 4.71%, 31.83%), respectively). Positive associations were also observed between PFNA, PFUnDA, perfluorooctane sulfonate (PFOS), and 6:2 Cl-PFESA and low-density lipoprotein cholesterol. However, no associations between PFASs and hemoglobin A1c, triglycerides, or high-density lipoprotein cholesterol reached statistical significance, nor associations between PFAS mixtures and outcomes of interest. In conclusion, the significant correlations between serum PFASs and glycemic biomarkers and lipid fractions indicated that PFAS exposure may be a potential diabetogenic factor. To the best of our knowledge, this is the first study to assess the associations between novel Cl-PFESAs and type 2 diabetes, although the inverse associations observed require clarification in future studies.

Associations between Exposures to Perfluoroalkyl Substances and Diabetes, Hyperglycemia, or Insulin Resistance: A Scoping Review

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental pollutants that are commonly found in the human body due to exposures via drinking water, surfactants used in consumer materials, and aqueous film-forming foams (AFFFs). PFAS exposure has been linked to adverse health effects such as low infant birth weights, cancer, and endocrine disruption, though increasingly studies have demonstrated that they may perturb metabolic processes and contribute to dysfunction. This scoping review summarizes the chemistry of PFAS exposure and the epidemiologic evidence for associations between exposure to per- and polyfluoroalkyl substances and the development of diabetes, hyperglycemia, and/or insulin resistance. We identified 11 studies on gestational diabetes mellitus, 3 studies on type 1 diabetes, 7 studies on type 2 diabetes, 6 studies on prediabetes or unspecified diabetes, and 15 studies on insulin resistance or glucose tolerance using the SCOPUS and PubMed databases. Approximately 24 reported positive associations, 9 negative associations, 2 non-linear associations, and 2 inverse associations, and 8 reported no associations found between PFAS and all diabetes search terms. Cumulatively, these data indicate the need for further studies to better assess these associations between PFAS exposure and diabetes.

Per- and Polyfluoroalkyl Substance and Cardio Metabolic Markers in Firefighters

OBJECTIVE

To evaluate if serum polyfluoroalkyl substances (PFAS) were associated with cardiometabolic markers.

METHODS

Serum PFAS were evaluated in 38 Arizona firefighters and 49 participants from the 2009 to 2010 National Health and Nutrition Examination Survey (NHANES). Cardiometabolic markers including carotid intima-medial thickness (CIMT) were measured in the firefighters.

RESULTS

Firefighters had elevated perfluorohexane sulfonic acid (PFHxS) and lower perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUA) compared to NHANES participants; for nine of the other 12 PFAS the values were not significantly different. There were significant negative associations among firefighters between perfluorodecanoic acid (PFDeA) and total cholesterol and PFUA and interleukin-6. PFAS concentrations were not associated with CIMT.

CONCLUSION

PFHxS levels were elevated in firefighters compared to NHANES subjects. Serum PFAS concentrations were not associated with increased cardiometabolic risk measures in this population of firefighters.

Perfluorooctane sulfonate alternatives and metabolic syndrome in adults: New evidence from the Isomers of C8 Health Project in China

Chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs), are ubiquitous alternatives to perfluorooctane sulfonate (PFOS), a widely used poly- and perfluoroalkyl substance (PFAS). Despite in vivo and in vitro evidence of metabolic toxicity, no study has explored associations of Cl-PFESAs concentrations with metabolic syndrome (MetS) in a human population. To help address this data gap, we quantified 32 PFAS, including 2 PFOS alternative Cl-PFESAs (6:2 and 8:2 Cl-PFESAs) in serum from 1228 adults participating in the cross-sectional Isomers of C8 Health Project in China study. The odds ratios (ORs) and 95% confidence intervals (CIs) of MetS and its various components were estimated using individual PFAS as a continuous or categorical predictor in multivariate regression models. The association between the overall mixture of PFAS and MetS was examined using probit Bayesian Kernel Machine Regression (BKMR-P). Greater serum PFAS concentrations were associated with higher odds of MetS and demonstrated a statistically significant dose-response trend (P for trend < 0.001). For example, each ln-unit (ng/mL) increase in serum 6:2 Cl-PFESA was associated with a higher prevalence of MetS (OR = 1.52, 95% CI: 1.25, 1.85). MetS was also 2.26 (95% CI: 1.59, 3.23) times more common in the highest quartile of serum 6:2 Cl-PFESA concentration than the lowest, and particularly high among women (OR = 6.41, 95% CI: 3.65, 11.24). The BKMR-P analysis showed a positive association between the overall mixture of measured PFAS and the odds of MetS, but was only limited to women. While our results suggest that exposure to Cl-PFESAs was associated with MetS, additional longitudinal studies are needed to more definitively address the potential health concerns of these PFOS alternatives.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Associations between serum isomers of perfluoroalkyl acids and metabolic syndrome in adults: Isomers of C8 Health Project in China

BACKGROUND

Exposure to perfluoroalkyl acids (PFAAs) is known to be associated with metabolic disorders. However, whether PFAAs isomers are associated with metabolic syndrome (MetS) still remains unknown.

OBJECTIVES

To explore the associations between serum PFAAs isomers and MetS.

METHODS

We recruited 1,501 adults from a cross-sectional study, the "Isomers of C8 Health Project in China" to investigate the associations between PFAAs isomers and MetS. A total of 20 PFAAs including the isomers of PFOS and PFOA were detected. Logistic regression models and restricted cubic spline models were used to evaluate the relationship of serum PFAAs isomers exposure with MetS and its components as well after adjusting for covariates.

RESULTS

The MetS prevalence in our study was 43.0%. The serum levels of both PFOS and PFOA isomers were higher in participants with MetS than that with non-MetS (p < 0.05). We found positive associations for per natural log-transformed ng/mL of branched perfluorooctane sulfonate (br-PFOS) (odds ratio (OR) = 1.18, 95% confidence interval (CI): 1.01, 1.38)) linear perfluoronanoic acid (n-PFOA) (OR = 1.35, 95% CI: 1.16, 1.58) and perfluoro-6-methylpheptanoic acid (6 m-PFOA) (OR = 1.32, 95% CI: 1.11, 1.57) with higher odds of MetS after covariates adjustment, while null association was observed for linear isomers of PFOS (OR = 1.09, 95% CI: 0.94, 1.25). We found a nonlinear dose-response relationship with a "threshold" effect in serum br-PFOS isomers with MetS, in which the odds of MetS increased quickly with increasing serum br-PFOS isomers under low exposure (p for nonlinearity = 0.030).

CONCLUSION

We report new evidence of associations between PFAAs isomers and MetS and the nonlinearity of dose-response relationship with br-PFOS isomers. Our findings indicate that more attention is needed to pay on the nonlinearity of dose-response relationship when investigate the association of PFAAs isomers with human health.

Perfluoroalkyl Substances and Metabolic Syndrome in Firefighters: A Pilot Study

OBJECTIVE

To compare association of perfluoroalkyl substances (PFASs) with metabolic syndrome (MetS) profile among firefighters (FF) at airport to suburban FF.

METHODS

Cross-sectional exploratory study, 47 men FF aged 18 to 62 years were enrolled from two fire departments in Ohio. Association between MetS outcome and log transformed serum concentrations of four PFASs was evaluated using multivariable logistic regression.

RESULTS

PFASs serum concentrations were 18% to 74% higher in FF than the general population, and 21% to 62% higher in airport FF than suburban FF. Compared with US general population, an elevated risk of hypertension was noted in FF, but no significant association between PFASs and MetS was found.

CONCLUSIONS

Current serum PFASs in FF are not associated with MetS risk.

Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research

Reports of environmental and human health impacts of per- and polyfluoroalkyl substances (PFAS) have greatly increased in the peer-reviewed literature. The goals of the present review are to assess the state of the science regarding toxicological effects of PFAS and to develop strategies for advancing knowledge on the health effects of this large family of chemicals. Currently, much of the toxicity data available for PFAS are for a handful of chemicals, primarily legacy PFAS such as perfluorooctanoic acid and perfluorooctane sulfonate. Epidemiological studies have revealed associations between exposure to specific PFAS and a variety of health effects, including altered immune and thyroid function, liver disease, lipid and insulin dysregulation, kidney disease, adverse reproductive and developmental outcomes, and cancer. Concordance with experimental animal data exists for many of these effects. However, information on modes of action and adverse outcome pathways must be expanded, and profound differences in PFAS toxicokinetic properties must be considered in understanding differences in responses between the sexes and among species and life stages. With many health effects noted for a relatively few example compounds and hundreds of other PFAS in commerce lacking toxicity data, more contemporary and high-throughput approaches such as read-across, molecular dynamics, and protein modeling are proposed to accelerate the development of toxicity information on emerging and legacy PFAS, individually and as mixtures. In addition, an appropriate degree of precaution, given what is already known from the PFAS examples noted, may be needed to protect human health. Environ Toxicol Chem 2021;40:606-630. © 2020 SETAC.

Per- and polyfluoroalkyl substance plasma concentrations and metabolomic markers of type 2 diabetes in the Diabetes Prevention Program trial

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widely used chemicals, some of which have been linked to type 2 diabetes. We tested whether PFAS concentrations were cross-sectionally associated with metabolites previously shown to predict incident type 2 diabetes using the Diabetes Prevention Program (DPP), a trial of individuals at high risk of type 2 diabetes.

METHODS

We evaluated 691 participants enrolled in the DPP with baseline measures of 10 PFAS (including total perfluorooctanesulfonic acid (PFOS), total perfluorooctanoic acid (PFOA), and Sb-PFOA [branched isomers of PFOA]) and 77 metabolites. We used log2-transformed PFAS concentrations as exposures and standardized metabolite concentrations as outcomes in linear regression models adjusted for age, sex, race/ethnicity, use of anti-hyperlipidemic or triglyceride-lowering medication, income, years of education, marital status, smoking, and family history of diabetes, with Benjamini-Hochberg linear step-up false discovery rate correction.

RESULTS

Sb-PFOA was associated with the largest number of tested metabolites (29 of 77). Each doubling in Sb-PFOA was associated with higher leucine (β = 0.07 [95%CI: 0.02, 0.11] SD) and lower glycine (-0.08 [95%CI: 0.03, -0.13] SD). Each doubling of either total PFOA or n-PFOA was associated with -0.13 [95%CI: 0.04, -0.22] SD lower glycine. PFOA and Sb-PFOA were positively associated with multiple triacylglycerols and diacylglycerols, and total PFOS, total PFOA, and Sb-PFOA were positively associated with phosphatidylethanolamines.

CONCLUSIONS

PFAS concentrations are associated with metabolites linked to type 2 diabetes (particularly amino acid, glycerolipid and glycerophospholipid pathways). Further prospective research is needed to test whether these metabolites mediate associations of PFAS and type 2 diabetes.

Associations of Perfluoroalkyl Substances with Prevalence of Metabolic Syndrome in Highly Exposed Young Adult Community Residents-A Cross-Sectional Study in Veneto Region, Italy

BACKGROUND

Studies on the association between perfluoroalkyl substances (PFAS) and metabolic syndrome (MetS) are limited, and results are inconsistent. We aimed to examine the associations between PFAS serum levels and the prevalence of MetS among highly exposed young adults (ages 20-39) residents of a large area of the Veneto Region (North-Eastern Italy) primarily stemming from PFAS water contamination before September 2013. A total of 15,876 eligible young adult residents living in the investigated municipalities were enrolled in the study from January 2017 to July 2019.

METHODS

MetS was defined by using a modified harmonized definition requiring the presence of 3 of the following: obesity (body mass index ≥30), elevated triglyceride (TG), reduced high-density lipoprotein cholesterol, elevated blood pressure, and hemoglobin A1c ≥ 6.1% or self-reported diabetes mellitus or drug treatment for hyperglycemia. Multivariable generalized additive models were performed to identify the associations between four serum PFAS, including perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA), and risk of MetS controlling for potential confounders.

RESULTS

A total of 1282 participants (8.1%) met the criteria of MetS with a higher prevalence among men. PFOA, PFHxS, and PFNA were not associated with the risk of MetS, whereas PFOS showed a consistent protective effect against the risk of MetS (OR 0.76, (95% CI: 0.69, 0.85) per ln-PFOS). However, we found statistically significant positive associations between PFAS serum levels and individual components of MetS, mainly elevated blood pressure and elevated TG.

CONCLUSION

Our results did not support a consistent association between PFAS and MetS and conflicting findings were observed for individual components of MetS.

Exposure to Perfluoroalkyl Chemicals and Cardiovascular Disease: Experimental and Epidemiological Evidence

Polyfluoro- and perfluoro-alkyl substances (PFAS) are organic chemicals extensively used worldwide for industry and consumer products. Due to their chemical stability, PFAS represent a major cause of environmental pollution. PFAS accumulate in animal and human blood and tissues exerting their toxicity. We performed a review of the epidemiological studies exploring the relationship between exposure to PFAS and thromboembolic cardiovascular disease. An increase in cardiovascular disease or death related to PFAS exposure has been reported from cross-sectional and longitudinal observational studies with evidence concerning the relation with early vascular lesions and atherosclerosis. Several studies indicate an alteration in lipid and glucose metabolism disorders and increased blood pressure as a possible link with cardiovascular thromboembolic events. We also examined the recent evidence indicating that legacy and new PFAS can be incorporated in platelet cell membranes giving a solid rationale to the observed increase risk of cardiovascular events in the populations exposed to PFAS by directly promoting thrombus formation. Exposure to PFAS has been related to altered plasma membrane fluidity and associated with altered calcium signal and increased platelet response to agonists, both in vitro and ex vivo in subjects exposed to PFAS. All the functional responses are increased in platelets by incorporation of PFAS: adhesion, aggregation, microvesicles release and experimental thrombus formation. These findings offer mechanistic support the hypothesis that platelet-centred mechanisms may be implicated in the increase in cardiovascular events observed in populations chronically exposed to PFAS.

Per- and polyfluoroalkyl substance mixtures and gestational weight gain among mothers in the Health Outcomes and Measures of the Environment study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent chemicals commonly used in the production of household and consumer goods. While exposure to PFAS has been associated with greater adiposity in children and adults, less is known about associations with gestational weight gain (GWG).

METHODS

We quantified using mass spectrometry perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), perfluorohexanesulfanoate (PFHxS) and perfluorononanoate (PFNA) in maternal serum from 18 ± 5 weeks' gestation (mean ± standard deviation (std)) in a prospective pregnancy and birth cohort (2003-2006, Cincinnati, Ohio) (n = 277). After abstracting weight data from medical records, we calculated GWG from 16 ± 2 weeks' gestation (mean ± std) to the measured weight at the last visit or at delivery, rate of weight gain in the 2nd and 3rd trimesters (GWR), and total weight gain z-scores standardized for gestational age at delivery and pre-pregnancy BMI. We investigated covariate-adjusted associations between individual PFAS using multivariable linear regression; we assessed potential effect measure modification (EMM) by overweight/obese status (pre-pregnancy BMI<25 kg/m2 v. ≥25 kg/m2). Using weighted quantile sum regression, we assessed the combined influence of these four PFAS on GWG and GWR.

RESULTS

Each doubling in serum concentrations of PFOA, PFOS, and PFNA was associated with a small increase in GWG (range 0.5-0.8 lbs) and GWR (range 0.03-0.05 lbs/week) among all women. The association of PFNA with GWG was stronger among women with BMI≥25 kg/m2 (β = 2.6 lbs; 95% CI:-0.8, 6.0) than those with BMI<25 kg/m2 (β = -1.0 lbs; 95% CI:-3.8, 1.8; p-EMM = 0.10). We observed associations close to the null between PFAS and z-scores and between the PFAS exposure index (a combined summary measure) and the outcomes.

CONCLUSION

Although there were consistent small increases in gestational weight gain with increasing PFOA, PFOS, and PFNA serum concentrations in this cohort, the associations were imprecise. Additional investigation of the association of PFAS with GWG in other cohorts would be informative and could consider pre-pregnancy BMI as a potential modifier.

Associations between perfluoroalkyl substances and lipid profile in a highly exposed young adult population in the Veneto Region

BACKGROUND

Residents of a large area of the Veneto Region (North-Eastern Italy) were exposed for decades to drinking water contaminated by perfluoroalkyl substances (PFAS). PFAS have been consistently associated with raised serum lipids, mainly in cross-sectional studies and in background exposure contexts, but the shape of the dose-response relationships has been poorly investigated. The objectives of our study were to evaluate the association between serum PFAS and serum lipids and their dose-response patterns in a large exposed population.

METHODS

A cross-sectional study was conducted in 16,224 individuals aged 20-39 years recruited in the regional health surveillance program. 15,720 subjects were analysed after excluding pregnant women (n = 327), participants reporting use of cholesterol lowering medications (n = 67) or with missing information on the selected covariates (n = 110). Twelve PFAS were measured by HPLC-MS in serum; three (PFOA, PFOS and PFHxS) were quantifiable in at least 50% of samples. Non-fasting serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and triglycerides were measured by enzymatic assays in automated analysers and low-density lipoprotein cholesterol (LDL-C), non-HDL cholesterol and total/HDL cholesterol ratio were calculated. The associations between natural log (ln) transformed PFAS and lipids were assessed through generalized additive models using linear regression and smoothing thin plate splines, adjusted for potential confounders.

RESULTS

There were strong positive associations between the ln-transformed PFOA, PFOS, and PFHxS and TC, HDL-C, and LDL-C, and between ln PFOA and PFHxS and triglycerides. Each ln-increase in PFOA was associated with an increase of 1.94 mg/dL (95% CI 1.48-2.41) in TC, with 4.99 mg/dL (CI 4.12-5.86) for PFOS and 2.02 mg/dL (CI 1.45-2.58) for PFHxS.

CONCLUSIONS

Investigation of the shape of exposure-response associations using splines showed a positive association with the largest increases per unit of PFAS in cholesterol levels occurring at the lower range of PFAS concentrations for each compound.

Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Umbilical Cord Blood DNA Methylation, and Cardio-Metabolic Indicators in Newborns: The Healthy Start Study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent chemicals widely detected in women of reproductive age. Prenatal PFAS exposure is associated with adverse health outcomes in children. We hypothesized that DNA methylation changes may result from prenatal PFAS exposure and may be linked to offspring cardio-metabolic phenotype.

OBJECTIVES

We estimated associations of prenatal PFAS with DNA methylation in umbilical cord blood. We evaluated associations of methylation at selected sites with neonatal cardio-metabolic indicators.

METHODS

Among 583 mother-infant pairs in a prospective cohort, five PFAS were quantified in maternal serum (median 27 wk of gestation). Umbilical cord blood DNA methylation was evaluated using the Illumina HumanMethylation450 array. Differentially methylated positions (DMPs) were evaluated at a false discovery rate ( FDR ) < 0.05 and differentially methylated regions (DMRs) were identified using comb-p (Šidák-adjusted p < 0.05 ). We estimated associations between methylation at candidate DMPs and DMR sites and the following outcomes: newborn weight, adiposity, and cord blood glucose, insulin, lipids, and leptin.

RESULTS

Maternal serum PFAS concentrations were below the median for females in the U.S. general population. Moderate to high pairwise correlations were observed between PFAS concentrations (ρ = 0.28 - 0.76 ). Methylation at one DMP (cg18587484), annotated to the gene TJAP1, was associated with perfluorooctanoate (PFOA) at FDR <   0.05 . Comb-p detected between 4 and 15 DMRs for each PFAS. Associated genes, some common across multiple PFAS, were implicated in growth (RPTOR), lipid homeostasis (PON1, PON3, CIDEB, NR1H2), inflammation and immune activity (RASL11B, RNF39), among other functions. There was suggestive evidence that two PFAS-associated loci (cg09093485, cg09637273) were associated with cord blood triglycerides and birth weight, respectively (FDR <   0.1 ).

DISCUSSION

DNA methylation in umbilical cord blood was associated with maternal serum PFAS concentrations during pregnancy, suggesting potential associations with offspring growth, metabolism, and immune function. Future research should explore whether DNA methylation changes mediate associations between prenatal PFAS exposures and child health outcomes. https://doi.org/10.1289/EHP6888.

Associations between apolipoprotein B and selected perfluoroalkyl substances among diabetics and nondiabetics

Previous population investigation of perfluoroalkyl substances (PFAS) features associations with lipids in a number of populations; these investigations have seldom included consideration of apolipoproteins. Apolipoprotein B (Apo B) fractions were considered in this descriptive analysis because they are essential to the assembly, transport, and cellular uptake of lipid classes associated with poorer health outcomes, and they are associated with incident and prevalent disease. Regression models stratified by diabetes and lipid lowering medication (LLM) status for data from National Health and Nutrition Examination Survey for 2007-2014 were fitted to interrogate associations between selected PFAS and Apo B for US adults aged ≥ 20 years. Adjusted concentrations of Apo B were positively associated with perfluorooctanoic acid (PFOA β = 0.03878, p < 0.01), perfluorooctane sulfonic acid (PFOS β = .02029, p = 0.02), and perfluorononanoic acid (PFNA β = .01968, p = .03) for nondiabetics who were not taking lipid lowering medications. These associations were not seen among diabetic participants, except for perfluorodecanoic acid (PFDA) in those taking LLMs (β = 0.03831, p = 0.02). We also note that LLMs have an inferred greater impact on Apo B in the diabetics compared to the nondiabetic populations. We have considered several sources of confounding and think the data are most consistent with a weak causal association that PFAS exposure increases Apo B. The rodent toxicology literature also contains evidence that PFAS disrupt fatty acid trafficking including Apo B, although how the specific findings may relate to circulating human Apo B concentrations is unclear. We therefore advocate for attempts to replicate the findings in other populations and to consider additional types of mechanistic studies.

Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs): Occurrence and Association with Serum Biochemical Parameters in Residents Living Near a Fluorochemical Plant in China

Although perfluoroalkyl ether carboxylic (PFECAs) and sulfonic acids (PFESAs) have been widely detected in environmental matrices, their occurrence in humans and impact on human health remains insufficiently understood. Here, we report on 13 PFECAs and PFESAs in 977 sera samples collected from residents living near a fluorochemical plant in Shandong, China. The sum concentration of these emerging PFECAs accounted for 13% of the total PFASs in the serum of the participants, with the frequent detection of several PFECAs (>95%) (PFMOAA, PFO4DA, and PFO5DoDA at median concentrations of 12.91, 0.142, and 0.987 ng/mL, respectively) and PFESAs (98.7%) (Nafion byproduct 2 at a median concentration of 0.097 ng/mL). Serum PFMOAA, PFO5DoDA, and 6:2 Cl-PFESA levels were significantly higher in males than in females. Positive relationships were observed between age and PFMOAA, 6:2 Cl-PFESA, and H-PFMO2OSA levels, whereas HFPO-TA and PFO5DoDA serum concentrations in the 0-40-year age group were lower than that in the >40-year age group. Furthermore, multivariate linear regression models and sensitivity analyses showed positive associations among PFO5DoDA levels, elevated lipid parameters (cholesterol, low-density lipoprotein cholesterol, and triglycerides), liver function markers (albumin levels and alanine transaminase, aspartate aminotransferase, and glutamyl transpeptidase activities), and uric acid levels. Thus, our results suggest potential health risks from exposure to novel PFESAs and PFECAs (especially PFO5DoDA).

PFAS Environmental Pollution and Antioxidant Responses: An Overview of the Impact on Human Field

Due to their unique properties, perfluorinated substances (PFAS) are widely used in multiple industrial and commercial applications, but they are toxic for animals, humans included. This review presents some available data on the PFAS environmental distribution in the world, and in particular in Europe and in the Veneto region of Italy, where it has become a serious problem for human health. The consumption of contaminated food and drinking water is considered one of the major source of exposure for humans. Worldwide epidemiological studies report the negative effects that PFAS have on human health, due to environmental pollution, including infertility, steroid hormone perturbation, thyroid, liver and kidney disorders, and metabolic disfunctions. In vitro and in vivo researches correlated PFAS exposure to oxidative stress effects (in mammals as well as in other vertebrates of human interest), produced by a PFAS-induced increase of reactive oxygen species formation. The cellular antioxidant defense system is activated by PFAS, but it is only partially able to avoid the oxidative damage to biomolecules.

Per- and Polyfluoroalkyl Substance Exposure, Gestational Weight Gain, and Postpartum Weight Changes in Project Viva

OBJECTIVE

The purpose of this study was to test the extent to which pregnancy per- and polyfluoroalkyl substance (PFAS) concentrations were associated with gestational weight gain and postpartum weight changes.

METHODS

This study was composed of 1,614 women recruited between 1999 and 2002 via the Project Viva cohort with pregnancy plasma concentrations of six PFAS, including perfluorooctanesulfonic acid, perfluorooctanoic acid (PFOA), and 2-(N-ethyl-perfluorooctane sulfonamido) acetic acid. Gestational weight gain was defined as the difference between last pregnancy weight and prepregnancy weight, 1-year postpartum weight retention as the difference between 1-year postpartum weight and prepregnancy weight, and 3-year postpartum weight change as the difference between 3-year postpartum weight and prepregnancy weight.

RESULTS

During pregnancy, women gained 0.37 kg (95% CI: 0.11-0.62) more weight per doubling of 2-(N-ethyl-perfluorooctane sulfonamido) acetic acid. At 1 year post partum, women retained 0.55 kg (95% CI: 0.07-1.04) more weight per doubling of PFOA. At 3 years post partum, women gained 0.91 kg (95% CI: 0.25-1.56) more weight per doubling in PFOA. Findings were similar after adjustment for all PFAS. Other PFAS were not associated with weight changes. Postpartum associations were stronger among women with higher prepregnancy BMI. Models were adjusted for demographics.

CONCLUSIONS

Pregnancy PFAS were associated with greater gestational weight gain, weight retention, and weight gain years after pregnancy.

Association between exposure to perfluoroalkyl substances and metabolic syndrome and related outcomes among older residents living near a Science Park in Taiwan

Perfluoroalkyl substances (PFASs) are an emerging class of artificial environmental chemicals that have multiple potentially harmful effects on health. The largest Science Park in Taiwan discharges wastewater containing PFASs into the Keya River, and a high concentration of PFASs has been found in this river and its aquatic creatures. We conducted a cross-sectional study from 2016 to 2017 of 397 subjects aged 55-75 years living near the river and evaluated the association of PFASs with metabolic syndrome and related outcomes. The results indicated that perfluorooctane sulfonate (PFOS) levels were positively associated with serum low-density lipoprotein (LDL) levels (P for trend = 0.03) and that perfluorononanoic acid (PFNA) and PFOS levels were positively correlated with uric acid levels (P for trend = 0.03 and 0.03). Perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnDA) levels were negatively associated with serum triglyceride levels (P for trend = 0.014 and < 0.01). After excluding lipid-lowering drug users, the association between certain PFAS levels and the LDL level was significantly enhanced, but the downward trends of serum triglyceride levels were weakened. When stratified by sex, PFNA (P for trend <0.01), perfluorohexanesulfonate (PFHxS) (P for trend <0.01), and PFOS (P for trend <0.01) showed positive associations with the uric acid level only among males. In conclusion, our results showed that associations were consistently null between PFASs and metabolic syndrome. PFAS levels were associated with serum lipids, and lipid-lowering drugs may interfere with this relationship. Certain PFASs were found to be positively associated with uric acid levels, especially in males. Further studies are warranted to clarify the causal relationships.

Risk to human health related to the presence of perfluoroalkyl substances in food

The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluoroalkyl substances (PFASs) in food. Based on several similar effects in animals, toxicokinetics and observed concentrations in human blood, the CONTAM Panel decided to perform the assessment for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS. These made up half of the lower bound (LB) exposure to those PFASs with available occurrence data, the remaining contribution being primarily from PFASs with short half-lives. Equal potencies were assumed for the four PFASs included in the assessment. The mean LB exposure in adolescents and adult age groups ranged from 3 to 22, the 95th percentile from 9 to 70 ng/kg body weight (bw) per week. Toddlers and 'other children' showed a twofold higher exposure. Upper bound exposure was 4- to 49-fold higher than LB levels, but the latter were considered more reliable. 'Fish meat', 'Fruit and fruit products' and 'Eggs and egg products' contributed most to the exposure. Based on available studies in animals and humans, effects on the immune system were considered the most critical for the risk assessment. From a human study, a lowest BMDL 10 of 17.5 ng/mL for the sum of the four PFASs in serum was identified for 1-year-old children. Using PBPK modelling, this serum level of 17.5 ng/mL in children was estimated to correspond to long-term maternal exposure of 0.63 ng/kg bw per day. Since accumulation over time is important, a tolerable weekly intake (TWI) of 4.4 ng/kg bw per week was established. This TWI also protects against other potential adverse effects observed in humans. Based on the estimated LB exposure, but also reported serum levels, the CONTAM Panel concluded that parts of the European population exceed this TWI, which is of concern.

Association of perfluoroalkyl substances with gestational hypertension and preeclampsia in the MIREC study

BACKGROUND

Perfluoroalkyl substances (PFAS) have been linked with a number of developmental, reproductive, hepatic, and cardiovascular health outcomes. However, the evidence for an association between PFAS and hypertensive disorders of pregnancy (including gestational hypertension and preeclampsia) is equivocal and warrants further investigation.

OBJECTIVES

To examine the relationship between background levels of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorohexane sulfonate (PFHxS) and the development of gestational hypertension or preeclampsia in a Canadian pregnancy cohort. We also explored the potential for effect modification according to fetal sex.

METHODS

Maternal plasma samples were collected in the first trimester from participants in the MIREC study and were analyzed for PFOA, PFOS, and PFHxS. Blood pressure was measured during each trimester. Gestational hypertension and preeclampsia were defined using the Society of Obstetricians and Gynaecologists of Canada guidelines. Logistic regression models were used to derive adjusted odds ratios (OR) and 95% confidence intervals (CI) for associations between PFAS concentrations (per doubling of concentration as well as according to tertiles) and gestational hypertension or preeclampsia. Linear mixed models were used to examine the association between PFAS concentrations and changes in blood pressure throughout pregnancy.

RESULTS

Data from 1739 participants were analyzed. 90% of women were normotensive throughout pregnancy, 7% developed gestational hypertension without preeclampsia, and 3% developed preeclampsia. In the full analyses, neither PFOA nor PFOS were associated with gestational hypertension or preeclampsia. However, each doubling of PFHxS plasma concentration was associated with higher odds of developing preeclampsia (OR = 1.32; 95% CI: 1.03, 1.70). In addition, participants in the highest PFHxS tertile (1.4-40.0 μg/L) had higher odds of developing preeclampsia relative to those in the lowest tertile (OR = 3.06; 95% CI: 1.27, 7.39). In stratified analyses, this effect was only apparent among women carrying a female fetus (OR = 4.90; 95% CI: 1.02, 22.3). However, among women carrying a male fetus, both PFOS and PFHxS were associated with gestational hypertension, but not preeclampsia. Higher plasma concentrations of all three PFAS were associated with increases in diastolic blood pressure throughout pregnancy, and PFOA and PFHxS were also associated with systolic blood pressure. Discrepant findings were similarly revealed in analyses stratified by fetal sex.

CONCLUSIONS

Higher levels of PFHxS were associated with the development of preeclampsia, but not gestational hypertension. Neither PFOA nor PFOS were associated with either outcome. However, we show, for the first time, that fetal sex may modify these associations, a finding which warrants replication and further study.

Per- and Polyfluoroalkyl Substances and Obesity, Type 2 Diabetes and Non-alcoholic Fatty Liver Disease: A Review of Epidemiologic Findings

Per- and polyfluoroalkyl substances, a group of fluoro-surfactants widely detected in the environment, wildlife and humans, have been linked to adverse health effects. A growing body of literature has addressed their effects on obesity, diabetes and non-alcoholic fatty liver disease/ non-alcoholic steatohepatitis. This review summarizes the brief historical use and chemistry of per- and polyfluoroalkyl substances, routes of human exposure, as well as the epidemiologic evidence for associations between exposure to per- and polyfluoroalkyl substances and the development of obesity, diabetes and non-alcoholic fatty liver disease/ non-alcoholic steatohepatitis. We identified 22 studies on obesity and 32 studies on diabetes, while only 1 study was found for non-alcoholic fatty liver disease/ non-alcoholic steatohepatitis by searching PubMed for human studies. Approximately 2/3 of studies reported positive associations between per- and polyfluoroalkyl substances exposure and the prevalence of obesity and/or type 2 diabetes. Causal links between per- and polyfluoroalkyl substances and obesity, diabetes and non-alcoholic fatty liver disease/ non-alcoholic steatohepatitis, however, require further large-scale prospective cohort studies combined with mechanistic laboratory studies to better assess these associations.