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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 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.

Introduction Psychiatric disorders are common and significantly impact the quality of life. Inflammatory processes are proposed to contribute to the emergence of psychiatric disorders. In addition to inflammation, disturbances in metabolic pathways have been observed in individuals with different psychiatric disorders. A suggested key player in the interaction between inflammation and metabolism is the Nod-like receptor 3 (NLRP3) inflammasome, and NLRP3 is known to react to a number of specific metabolites. However, little is known about the interplay between these immunometabolites and the NLRP3 inflammasome in mental health disorders. Aim To assess the interplay between immunometabolites and inflammasome function in a transdiagnostic cohort of individuals with severe mental disorders. Methods Mass spectrometry-based analysis of selected immunometabolites, previously known to affect inflammasome function, were performed in plasma from low-functioning individuals with severe mental disorders (n=39) and sex and aged-matched healthy controls (n=39) using a transdiagnostic approach. Mann Whitney U test was used to test differences in immunometabolites between psychiatric patients and controls. To assess the relationship between inflammasome parameters, disease severity, and the immunometabolites, Spearman’s rank-order correlation test was used. Conditional logistic regression was used to control for potential confounding variables. Principal component analysis was performed to explore immunometabolic patterns. Results Among the selected immunometabolites (n=9), serine, glutamine, and lactic acid were significantly higher in the patient group compared to the controls. After adjusting for confounders, the differences remained significant for all three immunometabolites. No significant correlations were found between immunometabolites and disease severity. Conclusion Previous research on metabolic changes in mental disorders has not been conclusive. This study shows that severely ill patients have common metabolic perturbations. The changes in serine, glutamine, and lactic acid could constitute a direct contribution to the low-grade inflammation observed in severe psychiatric disorders.

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.

Obesity is associated with adverse health outcomes, but the metabolic effects have not yet been fully elucidated. We aimed to investigate the association between adiposity with circulating metabolites and to address causality with Mendelian randomization (MR). Metabolomics data was generated by non-targeted ultra-performance liquid-chromatography coupled to time-of-flight mass-spectrometry in plasma and serum from three population-based Swedish cohorts: ULSAM (N=1,135), PIVUS (N=970), and TwinGene (N=2,059). We assessed associations between general adiposity measured as body mass index (BMI) and central body fat distribution measured as waist-to-hip ratio adjusted for BMI (WHRadjBMI) with 210 annotated metabolites. We employed MR analysis to assess causal effects. Lastly, we attempted to replicate the MR findings in the KORA and TwinsUK cohorts (N=7,373), the CHARGE consortium (N=8,631), the Framingham Heart Study (N=2,076) and the DIRECT consortium (N=3,029). BMI was associated with 77 metabolites, while WHRadjBMI was associated with 11 and 3 metabolites in women and men, respectively. The MR analyses in the Swedish cohorts suggested a causal association (p-value P-16:0) as well as with increased creatine levels. The replication effort provided support for a causal association of adiposity on reduced levels of arachidonic acid (p-value 0.03). Adiposity is associated with variation of large parts of the circulating metabolome, however causality needs further investigation in well-powered cohorts.

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.The major aim of this study was to see if a mixture of contaminants could improve the prediction of incident diabetes, using machine learning.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).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).This study supports the view that machine learning was useful in finding a mixture of important contaminants that improved prediction of incident diabetes. This improvement in prediction was seen only during the first 5 years of follow-up.

Context There is a dispute whether obesity without major metabolic derangements may represent a benign condition or not. Objective We aimed to compare the plasma metabolome in obese subjects without metabolic syndrome (MetS) with normal-weight subjects without MetS and with obese subjects with MetS. Methods This was a cross-sectional study at 2 academic centers in Sweden. Individuals from 3 population-based samples (EpiHealth, n = 2342, SCAPIS-Uppsala, n = 4985, and SCAPIS-Malmö, n = 3978) were divided into groups according to their body mass index (BMI) and presence/absence of MetS (National Cholesterol Education Program [NCEP]/consensus criteria). In total, 791 annotated endogenous metabolites were measured by ultra-performance liquid chromatography–tandem mass spectrometry. Results We observed major differences in metabolite profiles (427 metabolites) between obese (BMI ≥ 30 kg/m2) and normal-weight (BMI Conclusion Our data suggest a graded derangement of the circulating metabolite profile from lean to obese to MetS, in particular for metabolites involved in amino acid synthesis/metabolism and sphingolipid metabolism. Insulin resistance is a plausible mediator of this gradual metabolic deterioration.

Background: It has been suggested that per- and polyfluoroalkyl substances (PFAS) are endocrine disruptors with a potential to influence fat mass. Objective: The primary hypothesis tested was that we would find positive relationships for PFAS vs measures of adiposity. Methods: In 321 subjects all aged 50 years in the POEM study, five PFAS (perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA)) were measured in serum together with a Dual-energy X-ray absorptiometry (DXA) scan for determination of fat and lean mass. Whole-body magnetic resonance imaging scan was performed and the body was divided into >1 million voxels. Voxel-wise statistical analysis was carried out by a novel method denoted Imiomics. Results: PFOS and PFHxS, did not show any consistent associations with body composition. However, PFOA, and especially PFNA and PFDA, levels were inversely related to most traditional measures reflecting the amount of fat in women, but not in men. In the Imiomics analysis of tissue volume, PFDA and PFNA levels were inversely related to the volume of subcutaneous fat, mainly in the arm, trunk and hip regions in women, while no such clear relationship was seen in men. Also, the visceral fat content of the liver, the pericardium, and the gluteus muscle were inversely related to PFDA and PFNA in women. Discussion: Contrary to our hypothesis, some PFAS showed inverse relationships vs measurements of adiposity. Conclusion: PFOS and PFHxS levels in plasma did not show any consistent associations with body composition, but PFOA, and especially PFNA and PFDA were inversely related to multiple measures reflecting the amount of fat, but in women only.

Objective: The pathophysiology of hypertension remains incompletely understood. We investigated associations of circulating metabolites with longitudinal blood pressure (BP) changes in the Prospective Investigation of the Vasculature in Uppsala Seniors cohort and validated the findings in the Uppsala Longitudinal Study of Adult Men cohort. Approach and Results: Circulating metabolite levels were assessed with liquid- and gas-chromatography coupled to mass spectrometry among persons without BP-lowering medication at baseline. We studied associations of baseline levels of metabolites with changes in BP levels and the clinical BP stage between baseline and a follow-up examination 5 years later. In the discovery cohort, we investigated 504 individuals that contributed with 757 observations of paired BP measurements. The mean baseline systolic and diastolic BPs were 144 (19.7)/76 (9.7) mm Hg, and change in systolic and diastolic BPs were 3.7 (15.8)/−0.5 (8.6) mm Hg over 5 years. The metabolites associated with diastolic BP change were ceramide, triacylglycerol, total glycerolipids, oleic acid, and cholesterylester. No associations with longitudinal changes in systolic BP or BP stage were observed. Metabolites with similar structures to the 5 top findings in the discovery cohort were investigated in the validation cohort. Diacylglycerol (36:2) and monoacylglycerol (18:0), 2 glycerolipids, were associated with diastolic BP change in the validation cohort. Conclusions: Circulating baseline levels of ceramide, triacylglycerol, total glycerolipids, and oleic acid were positively associated with longitudinal diastolic BP change, whereas cholesterylester levels were inversely associated with longitudinal diastolic BP change. Two glycerolipids were validated in an independent cohort. These metabolites may point towards pathophysiological pathways of hypertension.

BackgroundEnvironmental factors are strongly implicated in late-onset of inflammatory bowel disease. Here, we investigate whether high exposure to perfluoroalkyl substances correlates with (1) late-onset inflammatory bowel disease, and (2) disturbances of the bile acid pool. We further explore the effect of the specific perfluoroalkyl substance perfluoronoctanoic acid on intestinal barrier function in murine tissue.MethodsSerum levels of perfluoroalkyl substances and bile acids were assessed by ultra-performance liquid chromatography coupled to a triple-quadrupole mass spectrometer in matched samples from patients with ulcerative colitis (n=20) and Crohn’s disease (n=20) diagnosed at the age of ≥55 years. Age and sex-matched blood donors (n=20), were used as healthy controls. Ex vivo Ussing chamber experiments were performed to assess the effect of perfluoronoctanoic acid on ileal and colonic murine tissue (n=9).ResultsThe total amount of perfluoroalkyl substances was significantly increased in patients with ulcerative colitis compared to healthy controls and patients with Crohn’s disease (pEx vivo exposure to perfluoronoctanoic acid induced a significanlty altered ileal and colonic barrier function. The distribution of bile acids, as well as the correlation pattern between (1) perfluoroalkyl substances and (2) bile acids, differed between patient and control groups.ConclusionOur results demonstrate that perfluoroalkyl substances levels are increased in patients with late-onset ulcerative colitis and may contribute to the disease by inducing a dysfunctional intestinal barrier.

Low biodegradability and high lipophilicity of p,p’-dichlorodiphenyldichloroethylene (DDE), a metabolite of the insecticide DDT, leads to transport with lipids and accumulation in adipose tissue. This persistence allows for DDE to effect adipose tissue and lipid metabolism. A few small human studies have shown an association between DDE and blood lipids, although with some inconsistent conclusions. The aim of this study was to investigate the association between DDE exposure and altered levels of circulating lipids in a large human cohort. To evaluate the associations between DDE and human lipid profiles, plasma was collected from a subset of elderly Swedes in the Prospective Investigation of the Vasculature of Uppsala Seniors (PIVUS) cohort who were free from lipid lowering medication (n = 571). DDE concentrations in plasma were measured using high-throughput solid phase extraction and gas chromatography-high resolution mass spectrometry. Lipidomic analysis of plasma was performed with nuclear magnetic resonance spectroscopy. Linear models of lipids and DDE were statistically adjusted for sex and body mass index. Detectable levels of DDE were found in the plasma samples of all subjects. With elevated DDE levels, the comprehensive lipoprotein profile showed an elevation in total concentration of all diameters of very low density lipoprotein (VLDL) (p VLDL > LDL > HDL) and within total serum (p

Over the past 20 years, the global incidence of chronic kidney disease (CKD) has been increasing and organochlorine pesticides (such as DDT) is a suspected etiological factor. The present study examines the associations between low level background exposure to p,p'-DDE (1-dichloro-2,2-bis (p-chlorophenyl) ethylene), the main DDT metabolite, and kidney function during a 10-year follow-up. Data was analysed from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 1016, 50% women, all aged 70 years). Serum levels of p,p'-DDE was measured by gas chromatography coupled to high-resolution mass spectrometry (GC/HRMS) at baseline (i.e. age of 70 years). Glomerular filtration rate (GFR) was estimated using serum creatinine and cystatin C at 70, 75 and 80 years of age. A significant decline in GFR was seen during the 10-year follow-up (-24 ml/min/1.73 m2, p 0.0001). A significant negative interaction was seen between baseline p,p'-DDE levels and change in GFR over time (p 0.0001) following adjustment for sex, systolic blood pressure, diabetes, BMI, smoking and education level at age 70. Subjects with the lowest levels of p,p'-DDE levels at age 70 showed the lowest decline in GFR over 10 years, while subjects with the highest p,p'-DDE levels showed the greatest decline. Baseline levels of p,p'-DDE were related to an accelerated reduction in GFR over 10 years suggesting a nephrotoxic effect of DDT/p,p'-DDE. These findings support a potential role for DDT in the epidemic of CKD of unknown etiology (CKDu) in agricultural communities of Sri Lanka and Central America where DDT was previously used.

Recent epidemiological studies suggest that human exposure to perfluoroalkyl substances (PFASs) may be associated with type 2 diabetes and other metabolic phenotypes. To gain further insights regar ...

Prospective cohort studies evaluating the temporal trends of background-level persistent organic pollutants (POPs) and their potential negative health effects in humans are needed.The objectives of this study are to examine the five year longitudinal trend in chlorinated and brominated (Cl/Br) POP concentrations in a sample of elderly individuals and to investigate the relationship between gender, changes in body weight, plasma lipid levels and POP concentrations.In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, plasma samples were collected from the same individuals over a 5 year period. Originally 992 subjects (all aged 70) were sampled between 2001 and 2004 and 814 returning subjects (all aged 75) were sampled again from 2006 to 2009. Plasma concentrations of 16 polychlorinated biphenyls (PCBs), 5 organochlorine pesticides (OCPs), octachlorinated dibenzo-p-dioxin (OCDD), and one polybrominated diphenylether (BDE 47) were determined using high-throughput 96-well plate solid phase extraction and gas chromatography-high resolution mass spectrometry (GC-HRMS).During the 5-year follow-up, plasma concentrations of all POPs significantly decreased (p 0.00001). Median reductions ranged from 4% (PCB105) to 45% (PCB 99), with most reductions being in the 30-40% range. For most POPs, a larger decline was seen in men than in women. The relationship between the weight change and change in POP concentrations was generally negative, but a positive relationship between lipid levels and POP concentrations when expressed as wet-weight was observed. In general, similar changes in POP concentrations and their relationships to body weight were observed regardless of using either wet-weight (pg/mL) or lipid-normalized (ng/g lipid) concentrations.In this longitudinal cohort study, gender and minor, but varying changes in body weight and lipid levels greatly influenced the individual-based changes in POP concentrations. In general, our findings suggest that men and women with larger decreases in body weight and greater increases in lipid levels have the slowest decline in body burden of POPs. Based on the results from this study, either wet-weight or lipid normalized concentrations can be used to determine the percent change in POP concentrations and their relationships to physiological changes and differences.

Background: While it is known that perfluoroalkyl substances (PFASs) induce liver toxicity in experimental studies, the evidence of an association in humans is inconsistent. Objective: The main aim of the present study was to examine the association of PFAS concentrations and markers of liver function using panel data. Methods: We investigated 1002 individuals from Sweden (50% women) at ages 70, 75 and 80 in 2001–2014. Eight PFASs were measured in plasma using isotope dilution ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). Bilirubin and hepatic enzymes alanine aminotransferase (ALT), alkaline phosphatase (ALP), and γ-glutamyltransferase (GGT) were determined in serum using an immunoassay methodology. Mixed-effects linear regression models were used to examine the relationship between the changes in markers of liver function and changes in PFAS levels. Results: The changes in majority of PFAS concentrations were positively associated with the changes in activity of ALT, ALP, and GGT and inversely associated with the changes in circulating bilirubin after adjustment for gender and the time-updated covariates LDL- and HDL-cholesterol, serum triglycerides, BMI, statin use, smoking, fasting glucose levels and correction for multiple testing. For example, changes in perfluorononanoic acid (PFNA) were associated with the changes liver function markers βBILIRUBIN = −1.56, 95% confidence interval (CI) −1.93 to −1.19, βALT = 0.04, 95% CI 0.03–0.06, and βALP = 0.11, 95% CI 0.06–0.15. Conclusion: Our longitudinal assessment established associations between changes in markers of liver function and changes in plasma PFAS concentrations. These findings suggest a relationship between low-dose background PFAS exposure and altered liver function in the general population. Keywords: Epidemiology, Liver function markers, PFAS, ALT, Bilirubin, PFNA

The objective of this study was to develop and validate a 96-well plate solid phase extraction method for analysis of 23 lipophilic persistent organic pollutants (POPs) in low-volume plasma and serum samples which is applicable for biomonitoring and epidemiological studies. The analysis of selected markers for internal exposure: 16 polychlorinated biphenyls (PCBs), 5 organochlorine pesticides (OCPs), octachlorinated dibenzo-p-dioxin (OCDD), and polybrominated diphenylether 47 (BDE 47) was evaluated by comparing two SPE sorbents and GC-HRMS or GC-MS/MS detection. The final method extracted 23 POPs from 150 μL of serum and plasma using a 96-well extraction plate containing 60 mg Oasis HLB sorbent per well prior to GC-HRMS magnetic sector analysis. The extraction method was applied to 40 plasma samples collected for an epidemiological study. The recovery of selected POPs ranged from 31% to 63% (n = 48), and detection limits ranged from 2.2 to 45 pg/mL for PCBs, 4.2 to 167 pg/mL for OCPs, 7.8 pg/mL for OCDD and 6.1 pg/mL for BDE 47. This method showed good precision with relative standard deviations of selected POP concentrations in quality control samples (n = 48) ranging from 11% to 25%. The trueness was determined with standard reference material serum (n = 48) and the deviation from certified values ranged from 1 to 27%. Of the 23 POPs analyzed, 18 were detected in 43% to 100% of plasma samples collected for the epidemiological study. The method showed good robustness with low inter-well plate variation (11-31%) determined by twelve 96-well plate extractions, and can extract 96 samples, including quality controls and procedural blanks in 2-3 days. Comparison with GC-MS/MS analysis showed that similar concentrations (within 0.5% to 30%) of most POPs could be obtained with GC-APCI-MS/MS. Larger deviations were observed for PCB 194 (60%) and trans-nonachlor (43%). The developed method produces accurate concentrations of low-level marker POPs in plasma and serum, providing a suitable high-throughput sample preparation procedure for biomonitoring and epidemiological studies involving large sample size and limited sample volume. GC-HRMS was chosen over GC-MS/MS, however the latter showed promising results, and could be used as an alternative to GC-HRMS analysis for most POPs.

Background Lipoproteins at aberrant levels are known to play a role in cardiovascular disease. The metabolite of the insecticide dichlorodiphenyltrichloroethane (DDT), p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE), physically associates with lipids and accumulates in adipose tissue. Little is known about which lipoproteins associate with p,p’-DDE. An association between p,p’-DDE exposure and altered levels of circulating lipids was assessed in a large human cohort using a detailed analysis of lipoprotein content. Methods Plasma samples were collected from the subset of 75-year old Swedes in the Prospective Investigation of the Vasculature of Uppsala Seniors (PIVUS) cohort who were not prescribed lipid lowering medication (n = 571). p,p’-DDE concentrations in plasma were measured using high-throughput solid phase extraction and gas chromatography-high resolution mass spectrometry. Analysis of plasma lipoprotein content was performed with nuclear magnetic resonance spectroscopy. Results Detectable levels of p,p’-DDE were found in the plasma samples of all subjects. Elevated p,p’-DDE levels were associated with increased concentrations of lipoproteins of all diameters, with the exception of high density lipoprotein (HDL) of diameters between 14.3 nm–10.9 nm. Of the lipoprotein constituents, triglycerides were most uniformly associated with elevated p,p’-DDE across lipoproteins. p,p’-DDE was furthermore associated with apolipoprotein B, but not apolipoprotein A1. Conclusions The positive associations observed between each lipoprotein class and elevated p,p’-DDE support previous data suggesting that p,p’-DDE interacts with lipoproteins within plasma. It is speculated that both physio-chemical and biological mechanisms may explain why p,p’-DDE does not uniformly associate with lipids across lipoproteins.

OBJECTIVESCeliac disease (CD) is a systemic immune-mediated disorder with increased frequency in the developed countries over the last decades implicating the potential causal role of various environmental triggers in addition to gluten. Herein, we apply determination of perfluorinated alkyl substances (PFAS) and combine the results with the determination of bile acids (BAs) and molecular lipids, with the aim to elucidate the impact of prenatal exposure on risk of progression to CD in a prospective series of children prior the first exposure to gluten (at birth and at 3 months of age).METHODSWe analyzed PFAS, BAs and lipidomic profiles in 76 plasma samples at birth and at 3 months of age in the Type 1 Diabetes Prediction and Prevention (DIPP) study (n=17 progressors to CD, n=16 healthy controls, HCs).RESULTSPlasma PFAS levels showed a significant inverse association with the age of CD diagnosis in infants who later progressed to the disease. Associations between BAs and triacylglycerols (TGs) showed different patterns already at birth in CD progressors, indicative of different absorption of lipids in these infants.DISCUSSIONPFAS exposure may modulate lipid and BA metabolism, and the impact is different in the infants who develop CD later in life, in comparison to HCs. The results indicate more efficient uptake of PFAS in such infants. Higher PFAS exposure during prenatal and early life may accelerate the progression to CD in the genetically predisposed children.Study HighlightsWHAT IS KNOWNSeveral observational studies have implicated a role of early life environmental triggers other than gluten in the development of CD. This is supported by the findings showing dysregulation of lipids already prior to the first introduction of gluten.WHAT IS NEW HEREWe show that prenatal exposure to perfluorinated compounds is associated with changes in the lipid metabolism, most likely through the bile acids, and that a high exposure during prenatal and early life may accelerate the progression to CD in the genetically predisposed children.TRANSLATIONAL IMPACTExposure to environmental chemicals may impact the rate of progression to CD and should be assessed as a potential risk factor of CD in larger clinical cohort settings.

Better risk prediction and new molecular targets are key priorities in type 2 diabetes (T2D) research. Little is known about the role of the urine metabolome in predicting the risk of T2D. We aimed to use non-targeted urine metabolomics to discover biomarkers and improve risk prediction for T2D. Urine samples from two community cohorts of 1,424 adults were analyzed by ultra-performance liquid chromatography/mass spectrometry (UPLC-MS). In a discovery/replication design, three out of 62 annotated metabolites were associated with prevalent T2D, notably lower urine levels of 3-hydroxyundecanoyl-carnitine. In participants without diabetes at baseline, LASSO regression in the training set selected six metabolites that improved prediction of T2D beyond established risk factors risk over up to 12 years' follow-up in the test sample, from C-statistic 0.866 to 0.892. Our results in one of the largest non-targeted urinary metabolomics study to date demonstrate the role of the urine metabolome in identifying at-risk persons for T2D and suggest urine 3-hydroxyundecanoyl-carnitine as a biomarker candidate.

There is evidence of a positive association between per- and polyfluoroalkyl substances (PFAS) and cholesterol levels in human plasma, which may be due to common reabsorption of PFAS and bile acids (BAs) in the gut. Here we report development and validation of a method that allows simultaneous, quantitative determination of PFAS and BAs in plasma, using 150 uL or 20 uL of sample. The method involves protein precipitation using 96-well plates. The instrumental analysis was performed with ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS), using reverse-phase chromatography, with the ion source operated in negative electrospray mode. The mass spectrometry analysis was carried out using multiple reaction monitoring mode. The method proved to be sensitive, robust and with sufficient linear range to allow reliable determination of both PFAS and BAs. The method detection limits were between 0.01 and 0.06 ng⋅mL-1 for PFAS and between 0.002 and 0.152 ng⋅mL-1 for BAs, with the exception of glycochenodeoxycholic acid (0.56 ng⋅mL-1). The PFAS measured showed excellent agreement with certified plasma PFAS concentrations in NIST SRM 1957 reference plasma. The method was tested on serum samples from 20 healthy individuals. In this proof-of-concept study, we identified significant associations between plasma PFAS and BA levels, which suggests that PFAS may alter the synthesis and/or uptake of BAs.

It has been suggested that persistent organic pollutants (POPs) are harmful to human health.To investigate if POP levels in plasma are associated with future mortality.Cohort study using data from the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, collected between May 2001 and June 2004 when participants reached age 70 years. Participants were followed up for 5 years after the first examination. Mortality was tracked from age 70 to 80 years. Data analysis was conducted in January and February 2018.Eighteen POPs identified by the Stockholm Convention, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and a brominated flame retardant, were measured in plasma levels by gas chromatography-mass spectrometry.All-cause mortality.The study sample initially included 992 individuals (497 [50.1%] men) aged 70 years, who were examined between 2001 and 2004. At the second examination 5 years later, 814 individuals (82.1%; 412 [50.7%] women) completed follow-up. During a follow-up period of 10.0 years, 158 deaths occurred. When updated information on POP levels at ages 70 and 75 years was associated with all-cause mortality using Cox proportional hazard analyses, a significant association was found between hexa-chloro- through octa-chloro-substituted (highly chlorinated) PCBs and all-cause mortality (except PCB 194). The most significant association was observed for PCB 206 (hazard ratio [HR] for 1-SD higher natural log-transformed circulating PCB 206 levels, 1.55; 95% CI, 1.26-1.91; P .001). Following adjustment for hypertension, diabetes, smoking, body mass index, and cardiovascular disease at baseline, most associations were no longer statistically significant, but PCBs 206, 189, 170, and 209 were still significantly associated with all-cause mortality (PCB 206: adjusted HR, 1.47; 95% CI, 1.19-1.81; PCB 189: adjusted HR, 1.29; 95% CI, 1.08-1.55; PCB 170: adjusted HR, 1.24; 95% CI, 1.02-1.52; PCB 209: adjusted HR, 1.29; 95% CI, 1.04-1.60). In a secondary analysis, these associations were mainly because of death from cardiovascular diseases rather than noncardiovascular diseases. Three organochlorine pesticides, including dichlorodiphenyldichloroethylene, and the brominated flame retardant diphenyl ether 47 were also evaluated but did not show any significant associations with all-cause mortality.Higher levels of highly chlorinated PCBs were associated with an increased mortality risk, especially from cardiovascular diseases. These results suggest that public health actions should be undertaken to minimize exposure to highly chlorinated PCBs.

Background In our daily life, we are exposed to perfluoroalkyl substances (PFAS) with possible health implications. The main exposure route for these substances is diet but comparative studies on how dietary habits influence exposure are lacking. Objectives To examine the relations between blood levels of PFAS and adherence to three predefined dietary patterns (a WHO recommended diet, a Mediterranean-like diet, and a Low-Carbohydrate High-Protein (LCHP) diet) in an elderly Swedish population. Methods Dietary data from 7-day food records and serum concentrations of PFAS were obtained from a 70-year-old Swedish population (n=844), the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. The Healthy Diet Indicator score (based on WHO recommendations), the Mediterranean Diet Score and LCHP score were used to assess adherence. Multivariate linear regression was used to assess the associations between eight major PFAS and adherence to each dietary pattern. Results The WHO recommended diet was positively associated with perfluorohexane sulfonic acid (PFHxS). The LCHP diet was positively related to four out of eight PFAS; namely, perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnDA). The Mediterranean-like diet was positively associated with most PFAS; namely perfluorooctanoic acid (PFOA), perfluorooctane sulfonamide (PFOSA), PFHxS, PFNA, PFDA, and PFUnDA. Conclusions All dietary patterns were positively associated with blood levels of PFAS. The highest body burden of PFAS was found in individuals with high adherence to a Mediterranean-like diet, whilst individuals who more closely followed the officially recommended diet displayed a lower body burden of these compounds.

Poly- and perfluoroalkyl substances (PFASs) are a group of man-made fluorinated chemicals which have, at background levels, been associated with negative health effects in humans. Thus far, most human biomonitoring studies have evaluated the general change in PFAS concentration over time by continuously testing various individuals. This is one of the few studies to report the longitudinal trend of a range of PFAS concentrations in humans. In addition, this is the first known longitudinal study to include a large background level exposed cohort of both men and women with the same age and location who were repeatedly sampled from 2001 to 2014.The longitudinal change in concentration of eight PFASs detected in serum collected from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort were determined and compared to results from general population studies. The sex-dependent changes in PFAS concentrations over time were also assessed.Serum was sampled from the same individuals at ages 70 (collection period 2001–2004), 75 (2006–2009) and 80 (2011–2014,). Eight (C6–11) of fourteen (C4–13) analyzed PFASs were usually detected in over 75% of individuals and assessed using a random effects (mixed) model.In the 579 individuals attending all three examinations, PFOSA and PFOS concentrations significantly decreased, while the remaining six PFASs significantly increased between ages 70 and 75. However, between ages 75 and 80 all PFAS concentrations significantly decreased. Overall from age 70 to 80, concentrations of PFHxS, PFUnDA, PFNA, and PFDA showed a significant increase (7% to 34%), whereas concentrations of PFOSA, PFHpA, PFOS, and PFOA (−75% to −27%) significantly decreased. Over time PFHxS concentrations increased more among women, while PFHpA concentrations showed a greater decrease among men.From age 70 to age 80, spanning from 2001‐2004 to 2011–2014, the PIVUS cohort showed decreases in circulating levels of some PFASs phased out of production with the exception of PFHxS and C>8 PFASs. Contrary to other studies, PFHxS concentrations showed the greatest overall increase, which is likely attributed to a local drinking water contamination incident. Keywords: Perfluoroalkyl substances, PFASs, Perfluoroalkyl acids, Longitudinal trends, Human serum, Biomonitoring

Background: Dichlorodiphenyldichloroethylene (p,p′-DDE) and hexachlorobenzene (HCB) are organochlorine pesticides with well-known endocrine disrupting properties. Exposure to p,p′-DDE and HCB concerns human populations worldwide and has been linked to metabolic disorders such as obesity and type 2 diabetes, but details about these associations in humans from the general population are largely unknown. Objectives: We investigated the associations between p,p′-DDE and HCB exposure and global metabolomic profiles in serum samples from 1016 participants from the Swedish population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Methods: HCB and p,p′-DDE levels were determined using gas chromatography coupled to high-resolution mass spectrometry (GC–HRMS). Metabolite levels were determined by using a non-targeted metabolomics approach with ultra-performance liquid chromatography coupled to time-of- flight mass spectrometry (UPLC–TOFMS). Association analyses were performed using multivariate linear regression. Results: We found circulating levels of p,p-DDE and HCB to be significantly associated with circulating levels of 16 metabolites following adjustment for age, sex, education level, exercise habits, smoking, energy intake, and alcohol intake. The majority of the 16 metabolites belong to lipid metabolism pathways and include fatty acids, glycerophospholipids, sphingolipids, and glycerolipids. Overall, p,p′-DDE and HCB levels were found to be correlated to different metabolites, which suggests that different metabolic fingerprints may be related to circulating levels of these two pesticides. Conclusions: Our findings establish a link between human exposure to organochlorine pesticides and metabolites of key metabolic processes mainly related to human lipid metabolism. Keywords: Organochlorine pesticides, Human exposure, Metabolomics, Metabolic effects, DDT, HCB

Background Environmental factors have been implicated in the pathogenesis of inflammatory bowel disease (IBD), particularly late onset disease. Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals with a long biological half-life that have been extensively used since the 1950s and have been proposed to interfere with the bile acid synthesis. Therefore, to investigate if late onset IBD correlates with higher PFAS levels, we measured serum levels of PFAS and bile acids in patients diagnosed with IBD later in life. Methods Serum samples were collected from patients diagnosed with ulcerative colitis (n = 20) and Crohn’s disease (n = 20) at the age of ≥55 years. Blood donors (n = 20) were used as healthy controls and were matched by gender and age. The levels of PFAS and bile acids were assessed by ultra performance liquid chromatography coupled to a triple quadrupole mass spectrometer. Results The total amount of PFAS was significantly higher in patients with ulcerative colitis compared with healthy controls (p = 0.021) or patients with Crohn’s disease (p = 0.015). No difference was found in total PFAS levels between Crohn’s disease patients and healthy controls (p = 0.841). Seven out of 30 bile acids correlated to the total PFAS level. Conclusion Our results demonstrate that PFAS levels are increased in patients with late-onset of ulcerative colitis compared with Crohn’s disease patients and healthy controls. This finding indicates that PFAS might represent an environmental risk factor for ulcerative colitis. However, additional studies assessing the functional consequences of increased PFAS in late-onset ulcerative colitis are required to confirm this hypothesis.

There are many small villages where environmental contamination is substantial due to historical industrial activities. The aim of the present study was to investigate if long-term or current consumption of local foods, as reported in food frequency questionnaires, co-vary with measured concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), lead (Pb), cadmium (Cd) and mercury (Hg) in blood, urine and hair from a population living in a historically contaminated village.Blood, urine and hair were provided by men (n = 38) and women (n = 57), who had participated in a previous case–control study in the contaminated area, and were analyzed for PCB, OCPs, Pb, Cd and Hg. A detailed food frequency questionnaire, used in the previous epidemiological study, was repeated, and up-dated information of life-style, exposure factors and other covariates was collected. Associations between reported consumption of local foods and exposure biomarkers were explored in relation to age, gender, life-style factors and other covariates.A large part of the population in the area reported consumption of local food, and thus, was potentially exposed to the contaminants. Despite the limited number of participants and other weaknesses described, it was possible to link reported consumption of different foods to biomarker concentrations.Reported consumption of local vegetables, forest berries and mushrooms co-varied with urinary Cd, indicating an influence from the contaminated area on the Cd exposure. We found no associations between PCB plasma concentrations with reported consumption of local fish, but with consumption of herring (non-local sea fish) which is typically high in PCB. Pesticide (HCB, p,p′-DDE, trans-nonachlor) exposure was mainly associated with agricultural work and having a private well the first five years of life, but we found no associations between pesticide concentrations in plasma and consumption of local vegetables or fish. Exposure to Hg was associated with consumption of fish, both local and non-local, and Pb exposure was associated with the consumption of game.Overall, the contaminant concentrations measured in blood, urine and hair varied substantially among study participants, but on average, the concentrations were similar to concentrations measured in other groups of the general Swedish population in the same age range. Larger studies are needed to evaluate health risks (and causality) associated with historical environmental contamination. Keywords: PCB, Metals, Exposure, Contaminated area, Consumption of local food