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Persistent organic pollutants (POPs) affect human health through the aryl hydrocarbon receptor (AhR) pathway and are implicated in mitochondrial dysfunction. Using data from the PIVUS study, we investigated the associations of serum AhR ligand (POP)-mediated luciferase activity (AhRL), mitochondrial ATP production inhibiting substances (MIS-ATP), and those affecting reactive oxygen species (MIS-ROS) with several metabolic syndrome (MetS) and cardiopulmonary function parameters. These include insulin resistance (HOMA-IR), inflammation, oxidative stress, and cardiopulmonary variables (FVC, FEV1, LV-EF, CCA distensibility). MIS-ATP showed significant correlations with HOMA-IR and pulmonary functions, indicating its direct impact of MIS-ATP on metabolic and pulmonary health. MIS-ROS correlated with oxidative stress markers and CCA distensibility, suggesting a role in systemic inflammatory responses. This study highlights the intricate relationships between environmental pollutant mixture and cardiopulmonary health in MetS as indicated by biomarkers of POP exposure in the elderly population, suggesting POP exposure may influence MetS onset and progression through mitochondrial dysfunction.

Isotope dilution ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS) is commonly used for trace analysis of polyfluoroalkyl and perfluoroalkyl substances (PFAS) in difficult matrices. Commercial nontargeted analysis of major PFAS where relative concentrations are obtained cost effectively is rapidly emerging and is claimed to provide comparable results to that of absolute quantification using matrix matched calibration and isotope dilution UHPLC–MS/MS. However, this remains to be demonstrated on a large scale. We aimed to assess the performance of a targeted absolute quantification isotope dilution LC–MS/MS assay versus a commercial nontargeted relative quantification assay for detection of three major PFAS in human blood. We evaluated a population-based cohort of 503 individuals. Correlations were assessed using Spearman's rank correlation coefficients (rho). Precision and bias were assessed using Bland–Altman plots. For perfluorooctane sulfonic acid, the median concentrations were 5.10 ng/mL (interquartile range [IQR] 3.50–7.24 ng/mL), the two assays correlated with rho 0.83. For perfluorooctanoic acid, the median concentrations were 2.14 ng/mL (IQR 1.60–3.0 ng/mL), the two assays correlated with rho 0.92. For perfluorohexanesulfonate, the median concentrations were 5.5 ng/mL (IQR 2.50–11.61 ng/mL), the two assays correlated with rho 0.96. The Bland–Altman statistical test showed agreement of the mean difference for the majority of samples (97–98%) between the two assays. Absolute plasma concentrations of PFAS obtained using matrix matched calibration and isotope dilution UHPLC–MS/MS show agreement with relative plasma concentrations from a nontargeted commercial platform by Metabolon. We observed striking consistency between the two assays when examining the associations of the three PFAS with cholesterol, offering additional confidence in the validity of utilizing the nontargeted approach for correlations with various health phenotypes.

Introduction: Effects of environmental contaminants (ECs) on endocrine systems have been reported, but few studies assessed associations between ECs and sex hormones (SH) in elderly. Aim of this study was to investigate whether blood concentrations of four classes of ECs were associated with SH concentrations in elderly. Methods: Samples from participants of the cross-sectional population-based Prospective Investigation of the Vasculature in Uppsala Seniors study (PIVUS, 70-year-old men and women, n = 1016) were analyzed using validated mass spectrometry-based methods for SH (testosterone (T), dihydrotestosterone (DHT), estrone and estradiol (E2)); 23 persistent organic pollutants (POPs); 8 perfluoroalkyl substances (PFAS); 4 phthalates and 11 metals. SH binding globulin (SHBG) was analyzed using immunoassay. The measured concentrations were normalized, and the values converted to a z-scale. Linear regression analyses were conducted to assess association between concentration of the SH, SHBG and E2/T (aromatase enzyme index, AEI) with the ECs. Multiple linear regression analyses were performed to model the relationships. Results: The strongest associations were observed with the polychlorinated biphenyls (PCBs). In men, the strongest associations with concentrations of SH and SHBG were seen for PCBs containing >5 chlorine, mono- ethyl phthalate (MEP), Ni and Cd; and in women, with PCBs, MEP, several of the PFAS, Cd, Co, and Ni. Difference in the effect of ECs on AEI between men and women were observed. Area under the ROC curve for the models predicting abnormal values of SH and SHBG >0.75 due to the effects of ECs was observed for T, DHT, and E2 in men, and for E2 and SHBG in women. Conclusions: Results of this study suggest that in elderly subjects, concentrations of many ECs associated with concentrations of SH and SHBG, and AEI. Further studies are needed to confirm the findings and to assess effect of the pollutants on endocrine system function in elderly.

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: beta: -0.03, p = 0.02, PFUnDA: beta: -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.

Background

Perfluoroalkyl substances (PFAS) are man-made chemicals with unique properties that are widely distributed in humans and the environment. Recent studies suggest that PFAS are involved in cholesterol metabolism, however, the mechanisms underlying the associations are poorly understood.

Objective

We aimed to evaluate associations of plasma PFAS with detailed lipid and lipoprotein subfractions in an adult population of men and women.

Methods

We measured concentrations of cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein subclasses, as well as fatty acid and different phospholipid measures, using serum proton nuclear magnetic resonance (1H-NMR), and four plasma PFAS using liquid chromatography-mass spectrometry (UHPLC-MS/MS). Measurements were available for 493 participants (all aged 50 years, 50% female). Multivariable linear regression was used to estimate the association of four PFAS with 43 different 1H-NMR measures, with adjustment for body mass index (BMI), smoking, education, and physical activity.

Results

We found that perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), but not perfluorohexanesulfonate (PFHxS), concentrations were consistently positively associated with concentrations of cholesterol in lipoprotein subfractions, apolipoproteins, as well as composite fatty acid- and phospholipid profiles. The most consistent associations were found for the relationship of PFAS with total cholesterol in intermediate-density lipoprotein (IDL), across all low-density lipoprotein (LDL) subfractions and small high-density lipoprotein (HDL). Moreover, we found weak to null evidence for an association of any of the measured 13 triglyceride lipoprotein subfractions with PFAS.

Conclusions

Our results suggest that plasma PFAS concentrations are associated with cholesterol in small HDL, IDL and all LDL subfractions, as well as apolipoproteins and composite fatty acid and phospholipid profiles but to a lesser extent with triglycerides in lipoproteins. Our findings draw attention to the need for more detailed measurements of lipids across various lipoprotein subfractions and subclasses in assessing the role of PFAS in lipid metabolism.

Impact

• By performing an in-depth characterization of circulating cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein, fatty acid, and phospholipid concentrations, this study has expanded upon the limited literature available on the associations of plasma PFAS concentrations beyond clinical routine laboratory testing for lipids.

Background: Many studies have been published on the relationships between different environmental contaminants and diabetes. In these studies, the environmental contaminants have most often been evaluated one by one, but in real life we are exposed to a mixture of contaminants that interact with each other. Objective: The major aim of this study was to see if a mixture of contaminants could improve the prediction of incident diabetes, using machine learning.

Methods: In the Prospective Investigation of the Vasculature in Uppsala (PIVUS) study (988 men and women aged 70 years), circulating levels of 42 contaminants from several chemical classes were measured at baseline. Incident diabetes was followed for 15 years. Six different machine-learning models were used to predict prevalent diabetes (n = 115). The variables with top importance were thereafter used to predict incident diabetes (n = 83).

Results: Boosted regression trees performed best regarding prediction of prevalent diabetes (area under the ROC -curve = 0.70). Following removal of correlated contaminants, the addition of nine selected contaminants (Cd, Pb, Trans-nonachlor the phthalate MiBP, Hg, Ni, PCB126, PCB169 and PFOS) resulted in a significant improvement of 6.0 % of the ROC curve (from 0.66 to 0.72, p = 0.018) regarding incident diabetes (n = 51) compared with a baseline model including sex and BMI when the first 5 years of the follow-up was used. No such improvement in prediction was seen over 15 years follow-up. The single contaminant being most closely related to incident diabetes over 5 years was Nickel (odds ratio 1.44 for a SD change, 95 % CI 1.05-1.95, p = 0.022).

Conclusion: This study supports the view that machine learning was useful in finding a mixture of important contam-inants that improved prediction of incident diabetes. This improvement in prediction was seen only during the first 5 years of follow-up.

Background: Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals that have been linked to increased cholesterol levels and thus may have a role in the development of cardiovascular disease (CVD).

Objectives: To investigate associations between PFAS exposure and incident CVD (a combined CVD end-point consisting of myocardial infarction, ischemic stroke, or heart failure) in two independent population-based cohorts in Sweden. In addition, we performed a meta-analysis also including results from previous studies.

Methods: In 2,278 subjects aged 45-75 years from the EpiHealth study, the risk of incident CVD in relation to relative plasma levels of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) was investigated. Associations between plasma levels of six PFAS and incident CVD were also examined in the PIVUS-study (n = 1,016, all aged 70 years). In addition, a meta-analysis was performed including three previous prospective studies, together with the results from the present study.

Results: There were no overall statistically significant associations between levels of the different PFAS and incident CVD, neither in EpiHealth nor in PIVUS. However, there was a significant sex interaction for PFOS in EpiHealth (p = 0.008), and an inverse association could be seen only in men (Men, HR: 0.68, 95 % CI: 0.52, 0.89) (Women, HR: 1.13, 95 % CI: 0.82, 1.55). A meta-analysis of five independent studies regarding PFOA and incident CVD showed a risk ratio (RR) of 0.80 (CI: 0.66, 0.94) when high levels were compared to low levels.

Conclusions: This longitudinal study using data from two population-based cohort studies in Sweden did not indicate any increased risk of incident CVD for moderately elevated PFAS levels. A meta-analysis of five independent cohort studies rather indicated a modest inverse association between PFOA levels and incident CVD, further supporting that increasing PFAS levels are not linked to an increased risk of CVD.

Background: Per- and polyfluoroalkyl substances (PFAS) have been linked to immunotoxic and cardiometabolic effects in both experimental and epidemiological studies, but with conflicting results.Aim: The aim of the present study was to investigate potential associations between plasma PFAS levels and plasma levels of preselected proteomic biomarkers previously linked to inflammation, metabolism and cardiovascular disease.

Methods: Three PFAS (perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS)) were measured by non-targeted metabolomics and 249 proteomic biomarkers were measured by the proximity extension assay (PEA) in plasma from 2,342 individuals within the Epidemiology for Health (EpiHealth) study from Sweden (45-75 years old, 50.6 % men).

Results: After adjustment for age and sex, 92% of the significant associations between PFOS concentrations and proteins were inverse (p < 0.0002, Bonferroni-adjusted). The results were not as clear for PFOA and PFHxS, but still with 80% and 64 % of the significant associations with proteins being inverse. After adjustment for age, sex, smoking, education, exercise habits and alcohol consumption, levels of epidermal growth factor receptor (EGFR), and paraoxonase type 3 (PON3) remained positively associated with all three PFAS, while resistin (RETN) and urokinase plasminogen activator surface receptor (uPAR) showed inverse associations with all three PFAS.

Conclusions: Our findings imply that PFAS exposure is cross-sectionally linked to altered levels of proteins previously linked to inflammation, metabolism and cardiovascular disease in middle-aged humans.

Background: Associations between per-and polyfluoroalkyl substances (PFAS), mainly PFOS and PFOA, and increased blood lipids have been reported primarily from cross-sectional studies. The aim of the present study was to investigate associations between multiple PFAS and blood lipids in a longitudinal fashion. Methods: A total of 864 men and women aged 70 years and free from lipid medication were included from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study from Uppsala Sweden, 614 and 404 of those were reinvestigated at age 75 and 80. At all three occasions, eight PFAS were measured in plasma using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were also measured in plasma at all three occasions. Mixed-effects linear regression models were used to examine the relationship between the changes in PFAS levels and changes in lipid levels. Results: Changes in plasma levels of six out of the eight investigated PFAS were positively associated with changes in plasma lipids after adjustment for sex, change in body mass index (BMI), smoking, physical activity, statin use (age was the same in all subjects), and correction for multiple testing. For example, changes in perfluorodecanoic acid (PFDA) were positively associated with the changes in total cholesterol (13: 0.23, 95% confidence interval (CI): 0.14 to 0.32), triglycerides (13: 0.08, 95% CI: 0.04-0.12) and HDL-cholesterol (13: 0.08, 95% CI: 0.04-0.11). Conclusion: In this longitudinal study with three measurements over 10 years of both plasma PFAS and lipids, changes in six out of the eight investigated PFAS were positively associated with changes in plasma lipids, giving further support for a role of PFAS exposure in human lipid metabolism.