Exposure to perfluoroalkyl substances (PFAS) and dyslipidemia, hypertension and obesity in adolescents. The Fit Futures study

A green analytical method for the simultaneous determination of 17 perfluoroalkyl substances (PFAS) in human serum and semen by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

The ubiquity of perfluoroalkyl substances has raised concerns about the unintended consequences of PFAS exposure on human health. In the present study, an eco-friendly ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of 17 PFAS in human serum and semen samples. QuEChERS salts MgSO4:NaCl 4:1 (w/w) were used for the extraction. The separation of analytes was performed on an ACQUITY BEH C18 column (100 × 2.1 mm, 1.7 μm), using water:methanol 95:5 and methanol as mobile phases A and B, respectively, both containing 2 mM ammonium acetate. Multiple reaction monitoring (MRM) in negative ion mode was used, selecting two transitions for each analyte, except for perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPeA). The analytical method was validated according to the Organization of Scientific Area Committees (OSAC) for Forensic Sciences guidelines and AGREE approach software was used to evaluate the greenness of the method. The developed procedure was applied to the analysis of 10 paired human serum and semen samples, proving the suitability in high throughput laboratories due to the easy preparation and the reduced volume of toxic solvents. Moreover, it allows to perform further investigation on the correlation between serum and semen PFAS concentration, focusing on male reproductive system correlated pathologies, such as male infertility.

Legacy and alternative per- and polyfluoroalkyl substances (PFAS) alter the lipid profile of HepaRG cells

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals used in various industrial and consumer products. They have gained attention due to their ubiquitous occurrence in the environment and potential for adverse effects on human health, often linked to immune suppression, hepatotoxicity, and altered cholesterol metabolism. This study aimed to explore the impact of ten individual PFAS, 3 H-perfluoro-3-[(3-methoxypropoxy) propanoic acid] (PMPP/Adona), ammonium perfluoro-(2-methyl-3-oxahexanoate) (HFPO-DA/GenX), perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluorodecanoic acid (PFDA), perfluorohexanoic acid (PFHxA), perfluorohexanesulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) on the lipid metabolism in human hepatocyte-like cells (HepaRG). These cells were exposed to different concentrations of PFAS ranging from 10 µM to 5000 µM. Lipids were extracted and analyzed using liquid chromatography coupled with mass spectrometry (LC- MS-QTOF). PFOS at 10 µM and PFOA at 25 µM increased the levels of ceramide (Cer), diacylglycerol (DAG), N-acylethanolamine (NAE), phosphatidylcholine (PC), and triacylglycerol (TAG) lipids, while PMPP/Adona, HFPO-DA/GenX, PFBA, PFBS, PFHxA, and PFHxS decreased the levels of these lipids. Furthermore, PFOA and PFOS markedly reduced the levels of palmitic acid (FA 16.0). The present study shows distinct concentration-dependent effects of PFAS on various lipid species, shedding light on the implications of PFAS for essential cellular functions. Our study revealed that the investigated legacy PFAS (PFOS, PFOA, PFBA, PFDA, PFHxA, PFHxS, and PFNA) and alternative PFAS (PMPP/Adona, HFPO-DA/GenX and PFBS) can potentially disrupt lipid homeostasis and metabolism in hepatic cells. This research offers a comprehensive insight into the impacts of legacy and alternative PFAS on lipid composition in HepaRG cells.

Determinants of per- and polyfluoroalkyl substances (PFAS) exposure among Wisconsin residents

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) include thousands of manufactured compounds with growing public health concerns due to their potential for widespread human exposure and adverse health outcomes. While PFAS contamination remains a significant concern, especially from ingestion of contaminated food and water, determinants of the variability in PFAS exposure among regional and statewide populations in the United States remains unclear.

OBJECTIVES

The objective of this study was to leverage The Survey of the Health of Wisconsin (SHOW), the only statewide representative cohort in the US, to assess and characterize the variability of PFAS exposure in a general population.

METHODS

This study sample included a sub-sample of 605 adult participants from the 2014-2016 tri-annual statewide representative sample. Geometric means for PFOS, PFOA, PFNA, PFHxS, PFPeS, PFHpA, and a summed measure of 38 analyzed serum PFAS were presented by demographic, diet, behavioral, and residential characteristics. Multivariate linear regression was used to determine significant predictors of serum PFAS after adjustment.

RESULTS

Overall, higher serum concentrations of long-chain PFAS were observed compared with short-chain PFAS. Older adults, males, and non-Hispanic White individuals had higher serum PFAS compared to younger adults, females, and non-White individuals. Eating caught fish in the past year was associated with elevated levels of several PFAS.

DISCUSSION

This is among the first studies to characterize serum PFAS among a representative statewide sample in Wisconsin. Both short- and long-chain serum PFAS were detectable for six prominent PFAS. Age and consumption of great lakes fish were the most significant predictors of serum PFAS. State-level PFAS biomonitoring is important for identifying high risk populations and informing state public health standards and interventions, especially among those not living near known contamination sites.

Associations of Serum Per- and Polyfluoroalkyl Substances with Hyperuricemia in Adults: A Nationwide Cross-Sectional Study

There has been widespread concern about the health hazards of per- and polyfluoroalkyl substances (PFAS), which may be the risk factor for hyperuricemia with evidence still insufficient in the general population in China. Here, we conducted a nationwide study involving 9,580 adults aged 18 years or older from 2017 to 2018, measured serum concentrations of uric acid and PFAS (PFOA, PFOS, 6:2 Cl-PFESA, PFNA, PFHxS) in participants, to assess the associations of individual PFAS with hyperuricemia, and estimated a joint effect of PFAS mixtures. We found positive associations of higher serum PFAS with elevated odds of hyperuricemia in Chinese adults, with the greatest contribution from PFOA (69.37%). The nonmonotonic dose-response (NMDR) relationships were observed for 6:2 Cl-PFESA and PFHxS with hyperuricemia. Participants with less marine fish consumption, overweight, and obesity may be the sensitive groups to the effects of PFAS on hyperuricemia. We highlight the potential health hazards of legacy long-chain PFAS (PFOA) once again because of the higher weights of joint effects. This study also provides more evidence about the NMDR relationships in PFAS with hyperuricemia and emphasizes a theoretical basis for public health planning to reduce the health hazards of PFAS in sensitive groups.

Association of co-exposure to organophosphate esters and per- and polyfluoroalkyl substances and mixture with cardiovascular-kidney-liver-metabolic biomarkers among Chinese adults

BACKGROUND

Organophosphate esters (OPEs) and Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with common exposure sources, leading to their widespread presence in human body. However, evidence on co-exposure to OPEs and PFAS and its impact on cardiovascular-kidney-liver-metabolic biomarkers remains limited.

METHODS

In this cross-sectional study, 467 adults were enrolled from January to May 2022 during physical visits in Shijiazhuang, Hebei province. Eleven types of OPEs and twelves types of PFAS were detected, among which eight OPEs and six PFAS contaminants were detected in more than 60% of plasma samples. Seventeen biomarkers were assessed to comprehensively evaluate the cardiovascular-kidney-liver-metabolic function. Multiple linear regression, multipollutant models with sparse partial least squares, and Bayesian kernel machine regression (BKMR) models were applied to examine the associations of individual OPEs and PFAS and their mixtures with organ function and metabolism, respectively.

RESULTS

Of the over 400 exposure-outcome associations tested when modelling, we observed robust results across three models that perfluorohexanoic acid (PFHxS) was significantly positively associated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and indirect bilirubin (IBIL). Perfluorononanoic acid was significantly associated with decreased AST/ALT and increased very-low-density lipoprotein cholesterol levels. Besides, perfluorodecanoic acid was correlated with increased high lipoprotein cholesterol and perfluoroundecanoic acid was consistently associated with lower glucose level. BKMR analysis showed that OPEs and PFAS mixtures were positively associated with IBIL and TBIL, among which PFHxS was the main toxic chemicals.

CONCLUSIONS

Our findings suggest that exposure to OPEs and PFAS, especially PFHxS and PFNA, may disrupt organ function and metabolism in the general population, providing insight into the potential pathophysiological mechanisms of OPEs and PFAS co-exposure and chronic diseases.

Exposure to per- and polyfluoroalkyl substances and alterations in plasma microRNA profiles in children

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that persist in the environment and can accumulate in humans, leading to adverse health effects. MicroRNAs (miRNAs) are emerging biomarkers that can advance the understanding of the mechanisms of PFAS effects on human health. However, little is known about the associations between PFAS exposures and miRNA alterations in humans.

OBJECTIVE

To investigate associations between PFAS concentrations and miRNA levels in children.

METHODS

Data from two distinct cohorts were utilized: 176 participants (average age 17.1 years; 75.6% female) from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort in the United States, and 64 participants (average age 6.5 years, 39.1% female) from the Rhea study, a mother-child cohort in Greece. PFAS concentrations and miRNA levels were assessed in plasma samples from both studies. Associations between individual PFAS and plasma miRNA levels were examined after adjusting for covariates. Additionally, the cumulative effects of PFAS mixtures were evaluated using an exposure burden score. Ingenuity Pathways Analysis was employed to identify potential disease functions of PFAS-associated miRNAs.

RESULTS

Plasma PFAS concentrations were associated with alterations in 475 miRNAs in the Teen-LABs study and 5 miRNAs in the Rhea study (FDR p < 0.1). Specifically, plasma PFAS concentrations were consistently associated with decreased levels of miR-148b-3p and miR-29a-3p in both cohorts. Pathway analysis indicated that PFAS-related miRNAs were linked to numerous chronic disease pathways, including cardiovascular diseases, inflammatory conditions, and carcinogenesis.

CONCLUSION

Through miRNA screenings in two independent cohorts, this study identified both known and novel miRNAs associated with PFAS exposure in children. Pathway analysis revealed the involvement of these miRNAs in several cancer and inflammation-related pathways. Further studies are warranted to enhance our understanding of the relationships between PFAS exposure and disease risks, with miRNA emerging as potential biomarkers and/or mediators in these complex pathways.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with risk of rheumatoid arthritis in the U.S. adult population

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are known environmental contaminants with immunosuppressive properties. Their connection to rheumatoid arthritis (RA), a condition influenced by the immune system, is not well studied. This research explores the association between PFAS exposure and RA prevalence.

METHODS

This research utilized data from the NHANES, encompassing a sample of 10,496 adults from the 2003-2018 cycles, focusing on serum levels of several PFAS. The presence of RA was determined based on self-reports. This study used multivariable logistic regression to assess the relationship between individual PFAS and RA risk, adjusting for covariates to calculate odds ratios (ORs). The combined effects of PFAS mixtures were evaluated using BKMR, WQS regression, and quantile g-computation. Additionally, sex-specific associations were explored through stratified analysis.

RESULTS

Higher serum PFOA (OR = 0.88, 95% CI: 0.79, 0.98), PFHxS (OR = 0.91, 95% CI: 0.83, 1.00), PFNA (OR = 0.87, 95% CI: 0.77, 0.98), and PFDA (OR = 0.89, 95% CI: 0.81, 0.99) concentration was related to lower odds of RA. Sex-specific analysis in single chemical models indicated the significant inverse associations were only evident in females. BKMR did not show an obvious pattern of RA estimates across PFAS mixture. The outcomes of sex-stratified quantile g-computation demonstrated that an increase in PFAS mixture was associated with a decreased odds of RA in females (OR: 0.76, 95% CI: 0.62, 0.92). We identified a significant interaction term of the WQS*sex in the 100 repeated hold out WQS analysis. Notably, a higher concentration of the PFAS mixture was significantly associated with reduced odds of RA in females (mean OR = 0.93, 95% CI: 0.88, 0.98).

CONCLUSIONS

This study indicates potential sex-specific associations of exposure to various individual PFAS and their mixtures with RA. Notably, the observed inverse relationships were statistically significant in females but not in males. These findings contribute to the growing body of evidence indicating that PFAS may have immunosuppressive effects.

Exposure to per- and polyfluoroalkyl substance and metabolic syndrome: A nationally representative cross-sectional study from NHANES, 2003-2018

Per- and polyfluoroalkyl substances(PFAS) are widespread organic pollutants with endocrine-disrupting effects on human health, but the association of PFAS exposure with metabolic syndrome remains conflicting. National Health and Nutrition Examination Survey(NHANES) program was utilized to evaluate the association of individual PFAS exposure and metabolic disorders and further determined the joint effect of PFAS co-exposures. 13921 participants and five PFAS exposures(PFHxS, MPAH, PFDE, PFNA, and PFUA) were included for analysis. The association between individual PFAS and metabolic syndrome varied in the specific PFAS and the specific metabolic disorder examined. PFHxS was negatively associated with obesity(Q4; OR = 0.75; P < 0.001), but positively associated with hyperlipidemia (Q3; OR = 1.2; P = 0.013). PFUA was negatively associated with obesity (Q4; OR = 0.6; P < 0.001), hyperlipidemia (Q3; OR = 0.85; P = 0.03), and non-alcoholic fatty liver disease (NAFLD, Q4; OR = 0.64; P = 0.015), but positively associated with hyperglycemia(Q3; OR = 1.27; P = 0.004). Furthermore, PFAS co-exposures were negatively associated with obesity(OR = 0.63; P < 0.001) and NAFLD(OR = 0.85; P = 0.021), and positively associated with hyperlipidemia(OR = 1.05; P = 0.022), but not significantly associated with hyperglycemia or hypertension. Overall, there was a negative association between PFAS co-exposures and metabolic severity score(β = -0.15; P < 0.001). Subgroup analysis stratified by gender and obesity consistently showed the negative association of PFAS co-exposures with metabolic severity score, and the positive association with hyperlipidemia. However, subgroup analysis showed a negative association with NAFLD in females but not in males, and a negative association with hyperglycemia in the obesity group, but not in the non-obesity group. Collectively, our study showed a negative association of PFAS co-exposures with metabolic syndrome severity score, but did not support a consistent association between PFAS co-exposures and individual components of metabolic syndrome. Additionally, there were gender-specific as well as BMI-specific differences in these associations. Further studies are needed to rule out the reverse causality and clarify the relationship of PFAS co-exposures with the specific metabolic disorder.

Evaluation of Lipids and Lipid-Related Transcripts in Human and Ovine Theca Cells and an in Vitro Mouse Model Exposed to the Obesogen Chemical Tributyltin

BACKGROUND

Exposure to obesogenic chemicals has been reported to result in enhanced adipogenesis, higher adipose tissue accumulation, and reduced ovarian hormonal synthesis and follicular function. We have reported that organotins [tributyltin (TBT) and triphenyltin (TPT)] dysregulate cholesterol trafficking in ovarian theca cells, but, whether organotins also exert lipogenic effects on ovarian cells remains unexplored.

OBJECTIVE

We investigated if environmentally relevant exposures to organotins [TBT, TPT, or dibutyltin (DBT)] induce lipid dysregulation in ovarian theca cells and the role of the liver X receptor (LXR) in this effect. We also tested the effect of TBT on oocyte maturation and neutral lipid accumulation, and lipid-related transcript expression in cumulus cells and preimplantation embryos.

METHODS

Primary theca cell cultures derived from human and ovine ovaries were exposed to TBT, TPT, or DBT (1, 10, or 50   ng / ml ). The effect of these chemical exposures on neutral lipid accumulation, lipid abundance and composition, lipid homeostasis-related gene expression, and cytokine secretion was evaluated using liquid chromatography-mass spectrometry (LC-MS), inhibitor-based methods, cytokine secretion, and lipid ontology analyses. We also exposed murine cumulus-oocyte complexes to TBT and evaluated oocyte maturation, embryo development, and lipid homeostasis-related mRNA expression in cumulus cells and blastocysts.

RESULTS

Exposure to TBT resulted in higher intracellular neutral lipids in human and ovine primary theca cells. In ovine theca cells, this effect was dose-dependent, independent of cell stage, and partially mediated by LXR. DBT and TPT resulted in higher intracellular neutral lipids but to a lesser extent in comparison with TBT. More than 140 lipids and 9 cytokines were dysregulated in TBT-exposed human theca cells. Expression of genes involved in lipogenesis and fatty acid synthesis were higher in theca cells, as well as in cumulus cells and blastocysts exposed to TBT. However, TBT did not impact the rates of oocyte maturation or blastocyst development.

DISCUSSION

TBT induced dyslipidemia in primary human and ovine theca cells, which may be responsible for some of the TBT-induced fertility dysregulations reported in rodent models of TBT exposure. https://doi.org/10.1289/EHP13955.

Dietary intake of Perfluorooctanesulfonic acid (PFOS) and glucose homeostasis parameters in a non-diabetic senior population

BACKGROUND

Endocrine disruptors (EDs) have emerged as potential contributors to the development of type-2 diabetes. Perfluorooctane sulfonate (PFOS), is one of these EDs linked with chronic diseases and gathered attention due to its widespread in food.

OBJECTIVE

To assess at baseline and after 1-year of follow-up associations between estimated dietary intake (DI) of PFOS, and glucose homeostasis parameters and body-mass-index (BMI) in a senior population of 4600 non-diabetic participants from the PREDIMED-plus study.

METHODS

Multivariable linear regression models were conducted to assess associations between baseline PFOS-DI at lower bound (LB) and upper bound (UB) established by the EFSA, glucose homeostasis parameters and BMI.

RESULTS

Compared to those in the lowest tertile, participants in the highest tertile of baseline PFOS-DI in LB and UB showed higher levels of HbA1c [β-coefficient(CI)] [0.01 %(0.002 to 0.026), and [0.06 mg/dL(0.026 to 0.087), both p-trend ≤ 0.001], and fasting plasma glucose in the LB PFOS-DI [1.05 mg/dL(0.050 to 2.046),p-trend = 0.022]. Prospectively, a positive association between LB of PFOS-DI and BMI [0.06 kg/m2(0.014 to 0.106) per 1-SD increment of energy-adjusted PFOS-DI was shown. Participants in the top tertile showed an increase in HOMA-IR [0.06(0.016 to 0.097), p-trend = 0.005] compared to participants in the reference tertile after 1-year of follow-up.

DISCUSSION

This is the first study to explore the association between DI of PFOS and glucose homeostasis. In this study, a high baseline DI of PFOS was associated with a higher levels of fasting plasma glucose and HbA1c and with an increase in HOMA-IR and BMI after 1-year of follow-up.

Early life poly- and perfluoroalkyl substance levels and adiposity in the first 2 years of life

IMPORTANCE

Poly- and perfluoroalkyl substances (PFASs) are nondegradable, man-made chemicals. They accumulate in humans with potential harmful effects, especially in susceptible periods of human development, such as the first months of life. We found that, in our cohort, exclusively breastfed (EBF) infants had 3 times higher PFAS plasma levels compared with exclusively formula-fed (EFF) infants at the age of 3 months. Thus, PFASs could potentially reduce the health benefits of breastfeeding.

OBJECTIVE

We investigated the associations between PFAS levels at the age of 3 months and accelerated gain in fat mass during the first 6 months of life, body composition at 2 years, and whether these associations differ between EBF and EFF infants.

SETTING

In 372 healthy term-born infants, we longitudinally assessed anthropometrics, body composition (by air-displacement plethysmography and dual-energy X-ray absorptiometry), and visceral and subcutaneous fat (by abdominal ultrasound) until the age of 2 years.

MEASURES

The plasma levels of 5 individual PFASs were determined by liquid chromatography-electrospray ionization-tandem mass spectrometry at the age of 3 months.

MAIN OUTCOMES

We studied associations between PFAS levels and outcomes using multiple regression analyses.

RESULTS

Higher early life plasma perfluorooctanoic acid and total PFAS levels were associated with an accelerated gain in fat mass percentage [FM%; >0.67 SD score (SDS)] during the first 6 months of life. Higher early life PFAS levels were associated with lower fat-free mass (FFM) SDS at the age of 2 years, but not with total FM% SDS at 2 years. Furthermore, we found opposite effects of PFAS levels (negative) and exclusive breastfeeding (positive) at the age of 3 months on FFM SDS at 2 years.

CONCLUSION

Higher PFAS levels in early life are associated with accelerated gains in FM% during the first 6 months of life and with lower FFM SDS at the age of 2 years, which have been associated with an unfavorable body composition and metabolic profile later in life. Our findings warrant further research with longer follow-up times.

Exploring the impact of prenatal perfluoroalkyl and polyfluoroalkyl substances exposure on blood pressure in early childhood: A longitudinal analysis

Previous research investigating the correlation between prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and subsequent blood pressure (BP) in offspring has yielded limited and contradictory findings. This study was conducted to investigate the potential relationship between maternal PFAS levels during pregnancy and subsequent BP in early childhood. A total of 129 expectant mothers from the Shanghai Birth Cohort were included in the study. Using high-performance liquid chromatography/tandem mass spectrometry, we measured ten PFAS compounds in maternal plasma throughout the pregnancy. When the children reached the age of 4, we examined their systolic BP (SBP) and diastolic BP (DBP), along with mean arterial pressure (MAP) and pulse pressure (PP). Data interpretation employed multiple linear and logistic regression models, complemented by Bayesian kernel machine regression (BKMR).We found that the majority of PFAS concentrations remained stable during pregnancy. The linear and BKMR models indicated a positive relationship between the PFAS mixture in maternal plasma and offspring's DBP and MAP, with perfluorohexanesulphonic acid (PFHxS) having the most significant influence (PFHxS and DBP [first trimester:β=3.03, 95%CI: (1.01,5.05); second trimester: β=2.35, 95%CI: (0.94,3.75); third trimester: β=2.57, 95%CI:(0.80,4.34)]; MAP [first trimester:β=2.55, 95%CI: (0.64,4.45); second trimester: β=2.28, 95%CI: (0.95,3.61); third trimester: β=2.35, 95%CI:(0.68,4.01)]). Logistic regression highlighted an increased risk of prehypertension and hypertension in offspring with higher maternal PFHxS concentrations during all three trimesters [first trimester: OR=2.53, 95%CI:(1.11,5.79), second trimester: OR=2.05, 95%CI:(1.11,3.78), third trimester: OR=3.08, 95%CI:(1.40,6.79)]. A positive correlation was identified between the half-lives of PFAS and the odds ratio (OR) of prehypertension and hypertension in childhood (β=0.139, P=0.010). In conclusion, this research found maternal plasma PFAS concentrations to be positively associated with BP in offspring, with PFHxS showing the most significant influence. This correlation remained consistent throughout pregnancy, and this effect was proportional to the half-lives of PFAS.

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.

The effect of PFAS exposure on glucolipid metabolism in children and adolescents: a meta-analysis

Background

Previous studies showed that per- and polyfluoroalkyl substances (PFAS), which are widely found in the environment, can disrupt endocrine homeostasis when they enter the human body. This meta-analysis aimed to evaluate current human epidemiological evidence on the relationship between PFAS exposure and glucolipid metabolism in childhood and adolescence.

Methods

We searched PubMed, Web of Science, Embase, and Cochrane Library databases, and identified population-based epidemiological studies related to PFAS and glucolipid metabolism indexes that were published before 30 December 2022. The heterogeneity of the included literature was assessed using the I-square (I2) test and statistics Q. Random-effects and fixed-effects models were used to combine the effect size. Subgroup analysis based on age and sex of the study participants was performed. A sensitivity analysis was used to evaluate the robustness and reliability of the combined results. Egger's and Begg's tests were used to analyze publication bias.

Results

A total of 12 studies were included in this analysis. There was a positive association between PFAS and TC (β = 1.110, 95% CI: 0.601, 1.610) and LDL (β = 1.900, 95% CI: 1.030, 2.770), and a negative association between PFAS and HOMA-IR in children and adolescents (β = -0.130, 95% CI: -0. 200, -0.059). PFOS was significant positive associated with TC (β = 8.22, 95% CI: 3.93, 12.51), LDL (β = (12.04, 95% CI: 5.08, 18.99), and HOMA-IR (β = -0.165, 95% CI: -0.292, -0.038). Subgroup analysis showed that exposure to PFAS in the adolescent group was positively associated with TC and LDL levels, and the relationship was stronger in females.

Conclusion

PFAS exposure is associated with glucolipid metabolism in children and adolescents. Among them, PFOS may play an important role. Recognition of environmental PFAS exposure is critical for stabilizing the glycolipid metabolism relationship during the growth and development of children and adolescents.

Exposure to perfluoroalkyl and polyfluoroalkyl substances and pediatric obesity: a systematic review and meta-analysis

INTRODUCTION

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are potentially obesogenic for children. We undertook a systematic review to synthesize this literature and explore sources of heterogeneity in previously published epidemiological studies.

METHODS

Studies that collected individual-level PFAS and anthropometric data from children up to 12 years of age were identified by searching six databases. We excluded studies that only evaluated obesity measures at the time of birth. A full-text review and quality assessment of the studies was performed using the Office of Health Assessment and Translation (OHAT) criteria. Forest plots were created to summarize measures of association and assess heterogeneity across studies by chemical type and exposure timing. Funnel plots were used to assess small-study effects.

RESULTS

We identified 24 studies, of which 19 used a cohort design. There were 13 studies included in the meta-analysis examining various chemicals and outcomes. Overall prenatal exposures to four different types of PFAS were not statistically associated with changes in body mass index (BMI) or waist circumference. In contrast, for three chemicals, postnatal exposures were inversely related to changes in BMI (i.e., per log10 increase in PFOS: BMI z-score of -0.16 (95% CI: -0.22, -0.10)). There was no substantial heterogeneity in the reported measures of association within prenatal and postnatal subgroups. We observed modest small-study effects, but correction for these effects using the Trim and Fill method did not change our summary estimate(s).

CONCLUSION

Our review found no evidence of a positive association between prenatal PFAS exposure and pediatric obesity, whereas an inverse association was found for postnatal exposure. These findings should be interpreted cautiously due to the small number of studies. Future research that can inform on the effects of exposure mixtures, the timing of the exposure, outcome measures, and the shape of the exposure-response curve is needed.

Evaluating the association between longitudinal exposure to a PFAS mixture and adolescent cardiometabolic risk in the HOME Study

Background

Exposure to per- and polyfluoroalkyl substances (PFAS) throughout gestation and childhood may impact cardiometabolic risk.

Methods

In 179 HOME Study participants (Cincinnati, OH; recruited 2003-2006), we used latent profile analysis to identify two distinct patterns of PFAS exposure from serum concentrations of four PFAS measured at birth and ages 3, 8, and 12 years. We assessed the homeostatic model of insulin resistance, triglycerides-to-high-density lipoprotein cholesterol ratio, leptin-to-adiponectin ratio, systolic blood pressure, visceral fat, and hemoglobin A1c levels at age 12 years. We used multivariable linear regression to assess the association of membership in the longitudinal PFAS mixture exposure group with a summary measure of overall cardiometabolic risk and individual components.

Results

One PFAS exposure profile (n = 66, 39%) had higher geometric means of all PFAS across all visits than the other. Although adjusted associations were null in the full sample, child sex modified the association of longitudinal PFAS mixture exposure group with overall cardiometabolic risk, leptin-to-adiponectin ratio, systolic blood pressure, and visceral fat (interaction term P values: 0.02-0.08). Females in the higher exposure group had higher cardiometabolic risk scores (ß = 0.43; 95% CI = -0.08, 0.94), systolic blood pressures (ß = 0.6; 95% CI = 0.1, 1.1), and visceral fat (ß = 0.44; 95% CI = -0.13, 1.01); males had lower cardiometabolic risk scores (ß = -0.52; 95% CI = -1.06, -0.06), leptin-to-adiponectin ratios (ß = -0.7; 95% CI = -1.29, -0.1), systolic blood pressures (ß = -0.14; 95% CI = -0.7, 0.41), and visceral fat (ß = -0.52; 95% CI = -0.84, -0.19).

Conclusions

Exposure to this PFAS mixture throughout childhood may have sex-specific effects on adolescent cardiometabolic risk.

Early menarche and other endocrine disrupting effects of per- and polyfluoroalkyl substances (PFAS) in adolescents from Northern Norway. The Fit Futures study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that are ubiquitous in the environment and include recognized persistent organic pollutants. The aim of this cross-sectional study was to investigate possible endocrine disrupting effects of different PFAS in adolescents.

METHODS

Serum concentrations of PFAS, thyroid, parathyroid and steroid hormones were measured in 921 adolescents aged 15-19 years in the Fit Futures study, Northern Norway. The questionnaire included data on self-reported age at menarche and puberty development score (PDS). Multiple linear and logistic regression analyses and principle component analyses (PCA) were used to assess associations of PFAS with hormones concentrations and puberty indices.

RESULTS

In girls, total PFAS (∑PFAS), perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), perfluorodecanoate (PFDA) were positively associated with dehydroepiandrosterone sulfate (DHEAS) and negatively associated with 11-deoxycorticosterone (11-DOC)/DHEAS ratio. In boys, the associations with 11-DOC/DHEAS ratio were positive for ∑PFAS, perfluoroheptanoate (PFHpA), perfluoroheptane sulfonate (PFHpS), PFOA, and PFOS. Perfluoroundecanoate (PFUnDA) was negatively associated with free thyroxine (fT4) and free triiodothyronine (fT3) in boys. PFNA and PFDA were also negatively associated with fT3 in boys. Serum parathyroid hormone concentration (PTH) was negatively associated with ∑PFAS and perfluorohexane sulfonate (PFHxS) in girls, and with PFOS in boys. PFDA and PFUnDA were positively associated with early menarche, while ∑PFAS and PFOA were positively associated with PDS in boys. No associations of PFAS with serum testosterone, follicle-stimulating hormone, or luteinizing hormone were found in either sex. In girls, PFOA was positively associated with free testosterone index (FTI). In boys, PFOA was positively associated with androstendione and 17-OH-progesterone, while PFHpA was positively associated with estradiol.

CONCLUSIONS

Serum concentrations of several PFAS were associated with parathyroid and steroid hormones in both sexes, and with thyroid hormones in boys, as well as with early menarche in girls and higher PDS in boys.

Development of interpretable machine learning models associated with environmental chemicals to predict all-cause and specific-cause mortality：A longitudinal study based on NHANES

Limited information is available on potential predictive value of environmental chemicals for mortality. Our study aimed to investigate the associations between 43 of 8 classes representative environmental chemicals in serum/urine and mortality, and further develop the interpretable machine learning models associated with environmental chemicals to predict mortality. A total of 1602 participants were included from the National Health and Nutrition Examination Survey (NHANES). During 154,646 person-months of follow-up, 127 deaths occurred. We found that machine learning showed promise in predicting mortality. CoxPH was selected as the optimal model for predicting all-cause mortality with time-dependent AUROC of 0.953 (95%CI: 0.951-0.955). Coxnet was the best model for predicting cardiovascular disease (CVD) and cancer mortality with time-dependent AUROCs of 0.935 (95%CI: 0.933-0.936) and 0.850 (95%CI: 0.844-0.857). Based on clinical variables, adding environmental chemicals could enhance the predictive ability of cancer mortality (P < 0.05). Some environmental chemicals contributed more to the models than traditional clinical variables. Combined the results of association and prediction models by interpretable machine learning analyses, we found urinary methyl paraben (MP) and urinary 2-napthol (2-NAP) were negatively associated with all-cause mortality, while serum cadmium (Cd) was positively associated with all-cause mortality. Urinary bisphenol A (BPA) was positively associated with CVD mortality.

Association of PFDeA exposure with hypertension (NHANES, 2013-2018)

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) is a series of artificial compounds which is associated with human health. However, there are few studies on the relationship between PFASs and hypertension. In this study, we examined the association between different kinds of PFASs and hypertension. Multivariable logistic regression and subgroup analysis were adopted to assess the associations between PFASs and hypertension. Spline smoothing plots and linear regression were used to assess the relationship between PFASs and blood pressure. We found a positive association between serum PFDeA concentrations and the prevalence of hypertension after fully adjusting confounders (OR = 1.2, P = 0.01), but other types of PFASs showed no positive results. Subgroup analysis stratified by ethnicity showed there was a stronger relationship among non-Hispanics than Hispanics. Serum PFDeA concentrations were positively associated with systolic pressure (β = 0.7, P< 0.01) and diastolic blood pressure (β = 0.8, P< 0.01) among non-Hispanics who did not take antihypertensive drugs. This study showed that PFDeA exposure was associated with hypertension in Americans who identify as non-Hispanic. There was a positive association between PFDeA and blood pressure in non-Hispanic Americans who did not take antihypertensive drugs.

Associations of a Prenatal Serum Per- and Polyfluoroalkyl Substance Mixture with the Cord Serum Metabolome in the HOME Study

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous and persistent chemicals associated with multiple adverse health outcomes; however, the biological pathways affected by these chemicals are unknown. To address this knowledge gap, we used data from 264 mother-infant dyads in the Health Outcomes and Measures of the Environment (HOME) Study and employed quantile-based g-computation to estimate covariate-adjusted associations between a prenatal (∼16 weeks' gestation) serum PFAS mixture [perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)] and 14,402 features measured in cord serum. The PFAS mixture was associated with four features: PFOS, PFHxS, a putatively identified metabolite (3-monoiodo-l-thyronine 4-O-sulfate), and an unidentified feature (590.0020 m/z and 441.4 s retention time; false discovery rate <0.20). Using pathway enrichment analysis coupled with quantile-based g-computation, the PFAS mixture was associated with 49 metabolic pathways, most notably amino acid, carbohydrate, lipid and cofactor and vitamin metabolism, as well as glycan biosynthesis and metabolism (P(Gamma) <0.05). Future studies should assess if these pathways mediate associations of prenatal PFAS exposure with infant or child health outcomes, such as birthweight or vaccine response.

Exposure to a Mixture of Endocrine-Disrupting Chemicals and Metabolic Outcomes in Belgian Adolescents

Childhood exposure to endocrine-disrupting chemicals (EDCs), either alone or in mixtures, may affect metabolic outcomes, yet existing evidence remains inconclusive. In our study of 372 adolescents from the Flemish Environment and Health Study (FLEHS IV, 2017-2018), we measured 40 known and suspected EDCs and assessed metabolic outcomes, including body mass index z-score (zBMI), abdominal obesity (AO), total cholesterol (TC), and triglycerides (TG). We applied Bayesian kernel machine regression (BKMR) and Bayesian penalized horseshoe regression for variable selection and then built multivariate generalized propensity score (mvGPS) models to provide an overview of the effects of selected EDCs on metabolic outcomes. As a result, BKMR and horseshoe together identified five EDCs associated with zBMI, three with AO, three with TC, and five with TG. Through mvGPS analysis, monoiso-butyl phthalate (MIBP), polychlorinated biphenyl (PCB-170), and hexachlorobenzene (HCB) each showed an inverse association with zBMI, as did PCB-170 with AO. Copper (Cu) was associated with higher TC and TG, except in boys where it was linked to lower TG. Additionally, monoethyl phthalate (MEP) and monobenzyl phthalate (MBzP) were associated with higher TG. To conclude, our findings support the association between certain chemicals (Cu, MEP, and MBzP) and elevated lipid levels, aligning with prior studies. Further investigation is needed for sex-specific effects.

Association between per- and polyfluoroalkyl substances (PFAS) and depression in U.S. adults: A cross-sectional study of NHANES from 2005 to 2018

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widespread persistent organic pollutants (POPs) associated with diseases including osteoporosis, altered immune function and cancer. However, few studies have investigated the association between PFAS mixture exposure and Depression in general populations.

METHODS

Nationally representative data from the National Health and Nutrition Examination Survey (NHANES) (2005-2018) were used to analyze the association between PFAS and Depression in U.S. adults. Total 12,239 adults aged 20 years or older who had serum PFAS measured and answered Patient Health Questionnaire-9 (PHQ-9) were enrolled in this study. PFAS monomers detected in all 7 investigation cycles were included in the study. Generalized additive model (GAM) was used to fit smooth curves and threshold effect analysis was carried out to find the turning point of smooth curves. Generalized linear model (GLM) was used to describe the non-linear relationship between PFAS and depression and unconditioned logistic regression was used to risk analysis.

RESULTS

The median of total serum PFAS concentration was 14.54 ng/mL. The curve fitting results indicated a U-shaped relationship between total serum PFAS and depression: PFAS< 39.66 ng/mL, A negative correlation between PHQ-9 score and serum PFAS concentration was observed (β 0.047,95%CI -0.059, -0.036). The depression PHQ-9 score decreased with the increase of serum PFAS concentration. PFAS ≥ 39.66 ng/mL, A positive correlation was observed between PFAS and PHQ-9 score (β 0.010,95% CI 0.003, 0.017). The depression PHQ-9 score increased with the increase of serum PFAS concentration.

CONCLUSIONS

Our study provides new clues to the association of PFAS with depression, and large population-based cohort studies that can validate the causal association as well as toxicological mechanism studies are needed for validation.

The Association of Hypertension with Perfluoroalkyl and Polyfluoroalkyl Substances

Perfluoroalkyl and polyfluoroalkyl substance (PFAS) is a large group of fluorinated synthetic chemicals, e.g., perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA). Many epidemiological studies have found that PFAS exposure is associated with hypertension risk, but others possess a different opinion. Overall, the relationship between PFASs and hypertension risk remains controversial. We sought to conduct a systematic review and meta-analysis to clarify the association between PFAS exposure and human risk of hypertension.We conducted a meta-analysis based on population-involving studies published from 1975 to 2023, which we collected from Web of Science, PubMed, and Embase databases. The odds ratio (OR) and standardized mean difference (SMD), with their 95% confidence interval (CI), were used to assess the risk of hypertension with PFAS exposure. The statistical heterogeneity among studies was assessed with the Q-test and I2 statistics. Research publications related to our meta-analysis topic were systematically reviewed.Fourteen studies involving 71,663 participants, in which 26,281 suffered hypertension, met the inclusion criteria. Our analyses suggest that exposure to general PFAS (OR = 1.09, 95% CI = 1.04-1.14) or PFOS (OR = 1.17, 95% CI = 1.05-1.30) is associated with hypertension risk. Specifically, elevated levels of general PFAS (SMD = 0.25, 95% CI = 0.08-0.42), PFHxS (SMD = 0.17, 95% CI = 0.07-0.27), and PFDA (SMD = 0.08, 95% CI = 0.02-0.13) are associated with a high risk of hypertension.Our meta-analysis indicates that PFAS exposure is a risk factor for hypertension, and increased hypertension risk is associated with higher PFAS levels. Further study may eventually provide a better and more comprehensive elucidation of the potential mechanism of this association.

Perfluoroalkyl substances in umbilical cord blood and blood pressure in offspring: a prospective cohort study

BACKGROUND

Humans are widely exposed to perfluoroalkyl substances (PFAS), which have been found to be associated with various adverse birth outcomes. As blood pressure (BP) is an important parameter reflecting cardiovascular health in early life, it is necessary to investigate the association of PFAS exposure during early lifetime and BP in childhood. Therefore, we investigated the potential association between PFAS levels in umbilical cord blood and BP of the offspring at 4 years of age in a prospective cohort study.

METHODS

PFAS in umbilical cord blood samples after birth were measured with high-performance liquid chromatography/tandem mass spectrometry in the Shanghai Birth Cohort. BP was measured at 4 years of age in the offspring. Multiple linear regression model was used to investigate the association between individual PFAS level and BP of the offspring. Bayesian kernel machine regression (BKMR) was used to analyze the relationship between the PFAS mixture and BP of the offspring, while weighted quantile sum (WQS) regression was utilized for sensitivity analysis.

RESULTS

A total of 129 mother-child pairs were included in our analysis. In multiple linear regressions, we observed that long-chain PFAS, mainly including perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUA), was negatively associated with systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP). BKMR showed that an increase in umbilical cord blood PFAS mixture levels was significantly associated with a decrease in SBP, DBP and MAP [Estimated differences (SD): -0.433 (0.161); -0.437 (0.176); -0.382 (0.179), respectively]. The most important component in the association with SBP, DBP, and MAP was PFUA. PFDoA was found to be positively associated with SBP, DBP and MAP in both models. Sensitivity analysis with WQS regression showed consistent results.

CONCLUSION

Our findings suggested that umbilical blood PFAS exposure was negatively associated with BP in offspring at 4 years of age, including SBP, DBP, and MAP.

Exposure characteristics of legacy and novel per- and polyfluoroalkyl substances in blood and association with hypertension among low-exposure population

The exposure characteristics of per- and polyfluoroalkyl substances (PFAS) in blood and their associations with hypertension have been well investigated in high-exposure populations, yet limited information is available concerning low-exposure populations. We conducted a cross-sectional study in a low-exposure population in China. A total of 394 females, including 162 with hypertension, were recruited and 30 PFAS were measured in whole blood samples. General linear model, generalized additive model, and logistic model were used to identify the associations with hypertension. Additionally, a Bayesian kernel machine regression model was conducted to test the mixture effects. Fourteen PFAS, including two novel species, 6:2 and 8:2 chlorinated polyfluorinated ether sulfonates (Cl-PFESAs), were detected, among which PFOS predominated with the highest median level of 1.47 ng/mL. The median levels of individual PFAS were, however, below the 25th, and even the 5th percentile of previous reports, except for PFHxA, which was above the 50th percentile (median of 0.10 ng/mL). After adjusting for covariates, PFHxA showed a positive association with hypertension (OR=1.54, 95% CI: 1.25, 1.89), while 6:2 Cl-PFESA showed a negative association (OR=0.73, 95% CI: 0.56, 0.95). PFAS didn't show significant mixture effects. We proposed that PFHxA may contribute to hypertension and 6:2 Cl-PFESA may have a hormesis effect.

Exposure to perfluoroalkyl and polyfluoroalkyl substances and risk of stroke in adults: a meta-analysis

INTRODUCTION

Evidence of the adverse metabolic health effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) is increasing. However, the impact of PFAS on cardiovascular diseases remains controversial. This meta-analysis aimed to analyze the impact of PFAS on the stroke risk.

CONTENT

Databases were searched for studies published up to November 1, 2022, which report the association between stroke and exposure to at least one of four main PFAS (perfluorooctanoic acid [PFOA], perfluorooctanesulfonic acid [PFOS], perfluorononanoic acid [PFNA], and perfluorohexane sulfonic acid [PFHxS]). Data extraction and quality assessment were performed according to the Newcastle-Ottawa scale.

SUMMARY AND OUTLOOK

Four studies were included in this systematic review. Multivariate adjusted odds ratios (ORs) for incident stroke per 1-log unit increment in each serum PFAS were combined in the meta-analysis. The risk of development of stroke was not significantly associated with PFOA, PFOS, or PFNA exposure (PFOA: pooled odds ratio [OR]=1.001, 95 % confidence interval [CI]=0.975-1.028, p=0.934; PFOS: pooled OR=0.994, 95 % CI=0.972-1.017, p=0.601; PFNA: pooled OR=1.016, 95 % CI=0.920-1.123, p=0.752), whereas a moderately lower risk was associated with PFHxS exposure without statistical significance (pooled OR=0.953, 95 % CI=0.908-1.001, p=0.054). PFOA, PFOS, and PFNA exposure showed a neutral association, while PFHxS showed a possible inverse association with the risk of stroke. Therefore, this finding should be interpreted with caution. Further prospective observational studies with PFAS mixture analyses are warranted.

Associations of perfluoroalkyl substances (PFAS) with lipid and lipoprotein profiles

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.

Prenatal and childhood exposure to per-/polyfluoroalkyl substances (PFASs) and its associations with childhood overweight and/or obesity: a systematic review with meta-analyses

BACKGROUND

Per-/polyfluoroalkyl substances (PFASs) are persistent organic pollutants and suspected endocrine disruptors.

OBJECTIVE

The aim of this work was to conduct a systematic review with meta-analysis to summarise the associations between prenatal or childhood exposure to PFASs and childhood overweight/obesity.

METHODS

The search was performed on the bibliographic databases PubMed and Embase with text strings containing terms related to prenatal, breastfeeding, childhood, overweight, obesity, and PFASs. Only papers describing a biomonitoring study in pregnant women or in children up to 18 years that assessed body mass index (BMI), waist circumference (WC), or fat mass in children were included. When the estimates of the association between a PFAS and an outcome were reported from at least 3 studies, a meta-analysis was conducted; moreover, to correctly compare the studies, we developed a method to convert the different effect estimates and made them comparable each other. Meta-analyses were performed also stratifying by sex and age, and sensitivity analyses were also performed.

RESULTS

In total, 484 and 779 articles were retrieved from PubMed and Embase, respectively, resulting in a total of 826 articles after merging duplicates. The papers included in this systematic review were 49: 26 evaluating prenatal exposure to PFASs, 17 childhood exposure, and 6 both. Considering a qualitative evaluation, results were conflicting, with positive, negative, and null associations. 30 papers were included in meta-analyses (19 prenatal, 7 children, and 4 both). Positive associations were evidenced between prenatal PFNA and BMI, between PFOA and BMI in children who were more than 3 years, and between prenatal PFNA and WC. Negative associations were found between prenatal PFOS and BMI in children who were 3 or less years, and between PFHxS and risk of overweight. Relatively more consistent negative associations were evidenced between childhood exposure to three PFASs (PFOA, PFOS, and PFNA) and BMI, in particular PFOS in boys. However, heterogeneity among studies was high.

CONCLUSION

Even though heterogeneous across studies, the pooled evidence suggests possible associations, mostly positive, between prenatal exposure to some PFASs and childhood BMI/WC; and relatively stronger evidence for negative associations between childhood exposure to PFASs and childhood BMI.

Association between per- and polyfluoroalkyl substances and risk of hypertension: a systematic review and meta-analysis

Background

Existing evidence indicates that exposure to per- and polyfluoroalkyl substances (PFASs) may increase the risk of hypertension, but the findings are inconsistent. Therefore, we aimed to explore the relationship between PFASs and hypertension through this systematic review and meta-analysis.

Methods

We searched PubMed, Embase, and the Web of Science databases for articles published in English that examined the relationship between PFASs and hypertension before 13 August 2022. The random effects model was used to aggregate the evaluation using Stata 15.0 for Windows. We also conducted subgroup analyses by region and hypertension definition. In addition, a sensitivity analysis was carried out to determine the robustness of the findings.

Results

The meta-analysis comprised 15 studies in total with 69,949 individuals. The risk of hypertension was substantially and positively correlated with exposure to perfluorooctane sulfonate (PFOS) (OR = 1.31, 95% CI: 1.14, 1.51), perfluorooctanoic acid (PFOA) (OR = 1.16, 95% CI: 1.07, 1.26), and perfluorohexane sulfonate (PFHxS) (OR = 1.04, 95% CI: 1.00, 1.09). However, perfluorononanoic acid (PFNA) exposure and hypertension were not significantly associated (OR = 1.08, 95% CI: 0.99, 1.17).

Conclusion

We evaluated the link between PFASs exposure and hypertension and discovered that higher levels of PFOS, PFOA, and PFHxS were correlated with an increased risk of hypertension. However, further high-quality population-based and pathophysiological investigations are required to shed light on the possible mechanism and demonstrate causation because of the considerable variability.

Systematic review registration

https://www.crd.york.ac.uk/prospero/ PROSPERO, registration number: CRD 42022358142.

The relationship between perfluoroalkyl substances and hypertension: A systematic review and meta-analysis

Hypertension is an important risk factor for cardiovascular diseases (CVDs) and a leading cause of premature death. Epidemiological studies have found that perfluoroalkyl substances (PFASs) are associated with hypertension. However, the correlation between PFASs and hypertension has not been systematically reported. Based on evidence from population epidemiological surveys, we conducted a meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess the correlation between PFASs exposure and hypertension. In this study, three databases of PubMed, Web of science, Embase were searched and 13 literatures with 81,096 participants were included. Literature heterogeneity was evaluated by I² statistic, and the random effect model (I² > 50%) and fixed effect model (I² < 50%) were used to combine the studies in meta-analysis. The results showed that PFNA (OR = 1.11, 95% CI: 1.04-1.19), PFOA (OR = 1.12, 95% CI: 1.02-1.23), PFOS (OR = 1.19, 95% CI: 1.06-1.34) and PFHxS (OR = 1.03, 95% CI: 1.00-1.06) were significantly associated with hypertension, while other types of PFASs (∑PFAS, PFDA, PFUnDA) had no statistical significance. In addition, PFNA (OR = 1.12, 95% CI: 1.03-1.22), PFOA (OR = 1.12, 95% CI: 1.01-1.25) and PFOS (OR = 1.12, 95% CI: 1.00-1.25) exposure were positively correlated with the risk of hypertension in men, but not in women. Our study reveals that PFASs are risk factors for hypertension, with notable gender differences observed in PFASs-exposed populations. Specifically, males exposed to PFNA, PFOA, and PFOS exhibit a higher risk of hypertension compared to females. However, further investigations are needed to delve into the precise mechanism through which PFASs contribute to the development of hypertension.

Destruction and defluorination of PFAS matrix in continuous-flow supercritical water oxidation reactor: Effect of operating temperature

Cleanup and disposal of stockpiles and waste streams containing per- and polyfluoroalkyl substances (PFAS) require effective end-of-life destruction/mineralization technologies. Two classes of PFAS, perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), are commonly found in legacy stockpiles, industrial waste streams, and as environmental pollutants. Continuous flow supercritical water oxidation (SCWO) reactors have been shown to destroy several PFAS and aqueous film-forming foams. However, a direct comparison of the SCWO efficacy for PFSAs and PFCAs has not been reported. We show the effectiveness of continuous flow SCWO treatment for a matrix of model PFCAs and PFSAs as a function of operating temperature. PFSAs appear to be significantly more recalcitrant than PFCAs in the SCWO environment. The SCWO treatment results in a destruction and removal efficiency of 99.999% at a T > 610 °C and at a residence time of ∼30 s. Fluoride recovery lags destruction PFAS at 510 °C and reaches >100% above 610 °C, confirming the formation of liquid and gaseous phase intermediate product during lower temperature oxidation. This paper establishes the threshold for destroying PFAS-containing liquids under SCWO conditions.

Exposure to high levels of PFAS through drinking water is associated with increased risk of type 2 diabetes-findings from a register-based study in Ronneby, Sweden

BACKGROUND

Epidemiological studies linking type 2 diabetes (T2D) and exposure to per- and polyfluoroalkyl substances (PFAS), are limited and have yielded conflicting results. This register-based study aimed to investigate the risk of T2D among Swedish adults who had been exposed to PFAS from highly contaminated drinking water for decades.

METHODS

The study included 55,032 adults (aged ≥18 years) from the Ronneby Register Cohort, who ever lived in Ronneby during 1985-2013. Exposure was assessed using the yearly residential address and the absence ("never-high") or presence ("ever-high") of high PFAS contamination in the municipal drinking water supply; the latter was subdivided into "early-high" and "late-high" exposure with cut-off at 2005. Incident T2D cases were retrieved from the National Patient Register and the Prescription Register. Cox proportional hazard models with time-varying exposure were used to estimate hazard ratios (HRs). Stratified analyses were performed based on age (18-45 vs > 45).

RESULTS

Elevated HRs for T2D were observed when comparing "ever-high" to "never-high" exposure (HR 1.18, 95% CI 1.03-1.35), as well as when comparing "early-high" (HR 1.12, 95% CI 0.98-1.50) or "late-high" (HR 1.17, 95% CI 1.00-1.37) to "never-high", after adjusting for age and sex. Individuals aged 18-45 years had even higher HRs. Adjusting for the highest-achieved education level attenuated the estimates, but the directions of associations remained. Elevated HRs were also found among those who had lived in areas with a heavily contaminated water supply for 1-5 years (HR 1.26, 95% CI 0.97-1.63) and 6-10 years (HR 1.25, 95% CI 0.80-1.94).

CONCLUSION

This study suggests an increased risk of T2D after long-term high PFAS exposure through drinking water. In particular, a higher risk of early onset diabetes was found, indicating increased susceptibility to PFAS-related health effects at younger ages.

Determinants of maternal and neonatal PFAS concentrations: a review

Per- and polyfluoroalkyl substances (PFAS) are used for their properties such as stain and water resistance. The substances have been associated with adverse health outcomes in both pregnant mothers and infants, including pre-eclampsia and low birthweight. A growing body of research suggests that PFAS are transferred from mother to fetus through the placenta, leading to in utero exposure. A systematic review was performed using the PubMed database to search for studies evaluating determinants of PFAS concentrations in blood matrices of pregnant mothers and neonates shortly after birth. Studies were included in this review if an observational study design was utilized, exposure to at least one PFAS analyte was measured, PFAS were measured in maternal or neonatal matrices, at least one determinant of PFAS concentrations was assessed, and results such as beta estimates were provided. We identified 35 studies for inclusion in the review and evaluated the PFAS and determinant relationships among the factors collected in these studies. Parity, breastfeeding history, maternal race and country of origin, and household income had the strongest and most consistent evidence to support their roles as determinants of certain PFAS concentrations in pregnant mothers. Reported study findings on smoking status, alcohol consumption, and pre-pregnancy body mass index (BMI) suggest that these factors are not important determinants of PFAS concentrations in pregnant mothers or neonates. Further study into informative factors such as consumer product use, detailed dietary information, and consumed water sources as potential determinants of maternal or neonatal PFAS concentrations is needed. Research on determinants of maternal or neonatal PFAS concentrations is critical to estimate past PFAS exposure, build improved exposure models, and further our understanding on dose-response relationships, which can influence epidemiological studies and risk assessment evaluations. Given the potential for adverse outcomes in pregnant mothers and neonates exposed to PFAS, it is important to identify and understand determinants of maternal and neonatal PFAS concentrations to better implement public health interventions in these populations.

Skeptical Look at the Clinical Implication of Metabolic Syndrome in Childhood Obesity

Metabolic syndrome (MetS) is defined by a cluster of several cardio-metabolic risk factors, specifically visceral obesity, hypertension, dyslipidemia, and impaired glucose metabolism, which together increase risks of developing future cardiovascular disease (CVD) and type 2 diabetes mellitus (T2D). This article is a narrative review of the literature and a summary of the main observations, conclusions, and perspectives raised in the literature and the study projects of the Working Group of Childhood Obesity (WGChO) of the Italian Society of Paediatric Endocrinology and Diabetology (ISPED) on MetS in childhood obesity. Although there is an agreement on the distinctive features of MetS, no international diagnostic criteria in a pediatric population exist. Moreover, to date, the prevalence of MetS in childhood is not certain and thus the true value of diagnosis of MetS in youth as well as its clinical implications, is unclear. The aim of this narrative review is to summarize the pathogenesis and current role of MetS in children and adolescents with particular reference to applicability in clinical practice in childhood obesity.

A review of cardiovascular effects and underlying mechanisms of legacy and emerging per- and polyfluoroalkyl substances (PFAS)

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly.

Untargeted Metabolomics Analysis Using UHPLC-Q-TOF/MS Reveals Metabolic Changes Associated with Hypertension in Children

The mechanism of hypertension in children remains elusive. The objective of this study was to analyze plasma metabolomics characteristics to explore the potential mechanism of hypertension in children. Serum samples from 29 control children, 38 children with normal body mass index and simple hypertension (NBp), 8 children overweight with simple hypertension (OBp), 37 children with normal body mass index and H-type hypertension (NH) and 19 children overweight with H-type hypertension (OH) were analyzed by non-targeted metabolomics. A total of 1235 differential metabolites were identified between children with hypertension and normal controls, of which 193 metabolites including various lipids were significantly expressed. Compared with the control group, 3-dehydroepiandrosterone sulfate, oleic acid and linoleic acid were up-regulated, and gamma-muricholic acid was down-regulated in the NBp group; 3-dehydroepiandrosterone sulfate, 4-acetamidobutanoate and 1-hexadecanoyl-2-octadecadienoyl-sn-glyero-3-phosphocholine were up-regulated in the OBp group, whereas adenosine and 1-myristoyl-sn-glyero-3-phosphocholine were down-regulated; in the NH group, 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine, phenol and 3-methoxytyramine were up-regulated, while pentadecanoic acid was down-regulated; in the OH group, NG,NG-dimethyl-L-arginine, 1-palmitoyl-sn-glycero-3-phosphocholine and monoethyl phthalate were up-regulated, while phloretin and glycine were down-regulated. The results showed that the children with hypertension had obvious disorders of lipid metabolism (especially in the overweight hypertension group), which led to the occurrence of hypertension. Additionally, the concentration of NO production-related NG, NG-dimethyl-L-arginine, was significantly increased, which may play an important role in H-type hypertension in children.

Serum concentrations of perfluoro-1-heptane sulfonate (PFHpS) among US adults: variabilities across different stages of kidney function

For the first time, data (N = 1311) from US National Health and Nutrition Examination Survey for 2017-2018 were analyzed for gender and racial/ethnic differences for perfluoro-1-heptane sulfonate (PFHpS) for US adults aged ≥ 20 years. In addition, variability in adjusted concentrations across various stages of glomerular filtration (GF) was also studied. While no racial/ethnic differences were observed, males had statistically significantly higher concentrations of PFHpS than females (0.30 vs. 0.19 ng/mL, p < 0.01). Concentrations of PFHpS across various stages of kidney function were located on inverted U-shaped curves with point of inflection located at GF-3A (45 ≤ eGFR < 60 mL/min/1.73 m²) for all participants, males, as well as females. After moderate increase from GF-1 (eGFR ≥ 60 mL/min/1.73 m²) to GF-2 (60 ≤ eGFR < 90 mL/min/1.73 m²), the increase in PFHpS concentration from GF-2 to GF-3A was quite steep. For example, for females, concentration from GF-1 to GF-2 increased from 0.17 ng/mL to 0.23 ng/mL for an increase of 35% but from GF-2 to GF-3A, concentrations of PFHpS increased from 0.23 ng/mL to 0.43 ng/mL for an increase of about 87%. Following this, at GF-3B/4 (15 ≤ eGFR < 45 mL/min/1.73 m²), concentrations decreased sharply to the almost the same levels as for GF-1. For example, for males, the decrease from GF-3A (0.67 ng/mL) to GF-3B/4 (0.21 ng/mL) was about 69%. Concentration curves for each race/ethnicity were also located on inverted U-shaped curves but relatively very small sample sizes for Hispanics and non-Hispanic Asians, and others at GF-3A and GF-3B/4 lead to substantial variability. The balance between reabsorption-excretion in favor of reabsorption at GF-1 and GF-2 switched to in favor of excretion starting at the end of GF-3A.

Long term toxicities following developmental exposure to perfluorooctanoic acid: Roles of peroxisome proliferation activated receptor alpha

Perfluorooctanoic acid (PFOA) is a widespread persistent organic pollutant. Fertile chicken eggs were exposed to PFOA and incubated to hatch. At three time points post hatch (0-, 1- and 3-months old), chickens were subjected to electrocardiography and sacrificed. Serum was subjected to LC-MS/MS for PFOA concentration, and organs were subjected to histopathological assessments. Additionally, PPARα-silencing lentivirus was co-applied with PFOA exposure, and the corresponding phenotypes were evaluated. Western blotting was performed to assess expressions of FABPs and pSMAD2 in heart and liver samples. Considerable amount of PFOA were detected in hatchling chicken serum, but not in one-month-old or three-month-old chicken serum. PFOA exposure resulted in developmental cardiotoxicity and hepatotoxicity in hatchling chickens. Meanwhile, one-month-old chickens still exhibited elevated heart rate, but classical cardiac remodeling (thicker right ventricular wall) were observed in exposed animals. Three-month-old chickens exhibited similar results as one-month-old ones. PPARα silencing only had partial protective effects in hatchling chickens, but the protective effects seemed to increase as chickens aged. Western blotting results indicated that L-FABP was involved in PFOA-induced hepatotoxicity, while pSMAD2 was involved in PFOA-induced cardiotoxicity. In summary, developmental exposure to PFOA resulted in persistent cardiotoxicity, but not hepatotoxicity. PPARα participates in both cardiotoxicity and hepatotoxicity.

PFAS levels and determinants of variability in exposure in European teenagers - Results from the HBM4EU aligned studies (2014-2021)

BACKGROUND

Perfluoroalkyl substances (PFAS) are man-made fluorinated chemicals, widely used in various types of consumer products, resulting in their omnipresence in human populations. The aim of this study was to describe current PFAS levels in European teenagers and to investigate the determinants of serum/plasma concentrations in this specific age group.

METHODS

PFAS concentrations were determined in serum or plasma samples from 1957 teenagers (12-18 years) from 9 European countries as part of the HBM4EU aligned studies (2014-2021). Questionnaire data were post-harmonized by each study and quality checked centrally. Only PFAS with an overall quantification frequency of at least 60% (PFOS, PFOA, PFHxS and PFNA) were included in the analyses. Sociodemographic and lifestyle factors were analysed together with food consumption frequencies to identify determinants of PFAS exposure. The variables study, sex and the highest educational level of household were included as fixed factors in the multivariable linear regression models for all PFAS and each dietary variable was added to the fixed model one by one and for each PFAS separately.

RESULTS

The European exposure values for PFAS were reported as geometric means with 95% confidence intervals (CI): PFOS [2.13 μg/L (1.63-2.78)], PFOA ([0.97 μg/L (0.75-1.26)]), PFNA [0.30 μg/L (0.19-0.45)] and PFHxS [0.41 μg/L (0.33-0.52)]. The estimated geometric mean exposure levels were significantly higher in the North and West versus the South and East of Europe. Boys had significantly higher concentrations of the four PFAS compared to girls and significantly higher PFASs concentrations were found in teenagers from households with a higher education level. Consumption of seafood and fish at least 2 times per week was significantly associated with 21% (95% CI: 12-31%) increase in PFOS concentrations and 20% (95% CI: 10-31%) increase in PFNA concentrations as compared to less frequent consumption of seafood and fish. The same trend was observed for PFOA and PFHxS but not statistically significant. Consumption of eggs at least 2 times per week was associated with 11% (95% CI: 2-22%) and 14% (95% CI: 2-27%) increase in PFOS and PFNA concentrations, respectively, as compared to less frequent consumption of eggs. Significantly higher PFOS concentrations were observed for participants consuming offal (14% (95% CI: 3-26%)), the same trend was observed for the other PFAS but not statistically significant. Local food consumption at least 2 times per week was associated with 40% (95% CI: 19-64%) increase in PFOS levels as compared to those consuming local food less frequently.

CONCLUSION

This work provides information about current levels of PFAS in European teenagers and potential dietary sources of exposure to PFAS in European teenagers. These results can be of use for targeted monitoring of PFAS in food.

Time-course trend and influencing factors for per- and polyfluoroalkyl substances in the breast milk of Korean mothers

Many studies have reported that neonates and infants are exposed to several per- and polyfluoroalkyl substances (PFASs) via breastfeeding; however, these studies have had small sample sizes. This study aimed to determine the concentrations and time-course trend of PFASs in breast milk and identify influencing factors governing PFAS concentrations. Between July and September (2018), 207 low-risk primiparous women were recruited from a lactation counseling clinic in Korea and their breast milk samples were tested for 14 PFASs, including four perfluoroalkyl sulfonic acids. A questionnaire survey, comprising 84 questions covering the women's demographic, obstetrical, dietary, lifestyle, behavioral, and neonatal information, was conducted to investigate associations. Twelve of the 14 PFASs were detectable in breast milk samples. Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorodecanoic acid were detected in 100% of the samples, followed by perfluorohexanesulfonic acid (detection rate: 87%), perfluorononanoic acid (87%), and perfluorohexanoic acid (73%); the median concentrations were 0.05, 0.10, 0.031, 0.007, and 0.033 ng/mL, respectively. The PFAS concentrations in breast milk measured in our study were higher than those reported in other studies or countries. In 12 years, from 2007 to 18, the mean concentration of PFOA in breast milk increased by approximately three times (278%). The major factors associated with PFAS concentrations in the bivariate association analysis were body mass index; living area (non-metropolitan); neonatal age; and frequency of fish, ice cream, and canned food consumption. In the multiple regression model, fish consumption significantly influenced the PFOS concentrations in breast milk (β = 0.88, p = 0.033). Frequently, fish consumption has been analyzed as the main dietary factor related to PFOS concentration. Our findings suggest the need for a comprehensive cohort study on PFAS exposure and its association with infant health.

Toxic effects of per- and polyfluoroalkyl substances on sperm: Epidemiological and experimental evidence

As emerging organic contaminants, per- and polyfluoroalkyl substances (PFASs) have aroused worldwide concern due to their environmental persistence, ubiquitous presence, bioaccumulation, and potential toxicity. It has been demonstrated that PFASs can accumulate in human body and cause multiple adverse health outcomes. Notably, PFASs have been detected in the semen of human, posing a potential hazard to male fecundity. This article reviews the evidence about the toxic effects of exposure to PFASs on male reproduction, focusing on the sperm quality. Epidemiological studies showed that PFASs, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), were adversely associated with the semen parameters in humans, including sperm count, morphology and motility. Experimental results also confirmed that PFAS exposure led to testicular and epididymal damage, therefore impairing spermatogenesis and sperm quality. The mechanisms of reproductive toxicity of PFASs may be involved in blood-testosterone barrier destruction, testicular apoptosis, testosterone synthesis disorder, and membrane lipid composition alteration, oxidative stress and Ca²⁺ influx in sperm. In conclusion, this review highlighted the potential threat of exposure to PFASs to human spermatozoa.

Cross-sectional associations between exposure to per- and polyfluoroalkyl substances and body mass index among European teenagers in the HBM4EU aligned studies

Per- and polyfluoroalkyl substances (PFAS) are widespread pollutants that may impact youth adiposity patterns. We investigated cross-sectional associations between PFAS and body mass index (BMI) in teenagers/adolescents across nine European countries within the Human Biomonitoring for Europe (HBM4EU) initiative. We used data from 1957 teenagers (12-18 yrs) that were part of the HBM4EU aligned studies, consisting of nine HBM studies (NEBII, Norway; Riksmaten Adolescents 2016-17, Sweden; PCB cohort (follow-up), Slovakia; SLO CRP, Slovenia; CROME, Greece; BEA, Spain; ESTEBAN, France; FLEHS IV, Belgium; GerES V-sub, Germany). Twelve PFAS were measured in blood, whilst weight and height were measured by field nurse/physician or self-reported in questionnaires. We assessed associations between PFAS and age- and sex-adjusted BMI z-scores using linear and logistic regression adjusted for potential confounders. Random-effects meta-analysis and mixed effects models were used to pool studies. We assessed mixture effects using molar sums of exposure biomarkers with toxicological/structural similarities and quantile g-computation. In all studies, the highest concentrations of PFAS were PFOS (medians ranging from 1.34 to 2.79 μg/L). There was a tendency for negative associations with BMI z-scores for all PFAS (except for PFHxS and PFHpS), which was borderline significant for the molar sum of [PFOA and PFNA] and significant for single PFOA [β-coefficient (95% CI) per interquartile range fold change = -0.06 (-0.17, 0.00) and -0.08 (-0.15, -0.01), respectively]. Mixture assessment indicated similar negative associations of the total mixture of [PFOA, PFNA, PFHxS and PFOS] with BMI z-score, but not all compounds showed associations in the same direction: whilst [PFOA, PFNA and PFOS] were negatively associated, [PFHxS] associated positively with BMI z-score. Our results indicated a tendency for associations of relatively low PFAS concentrations with lower BMI in European teenagers. More prospective research is needed to investigate this potential relationship and its implications for health later in life.

Exposure to a mixture of per-and polyfluoroalkyl substances modulates pulmonary expression of ACE2 and circulating hormones and cytokines

Genetic and environmental factors impact on the interindividual variability of susceptibility to communicable and non-communicable diseases. A class of ubiquitous chemicals, Per- and polyfluoroalkyl substances (PFAS) have been linked in epidemiological studies to immunosuppression and increased susceptibility to viral infections, but possible mechanisms are not well elucidated. To begin to gain insight into the role of PFAS in susceptibility to one such viral infection, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), male and female C57BL/6 J mice were exposed to control water or a mixture of 5 PFAS (PFOS, PFOA, PFNA, PFHxS, Genx) for 12 weeks and lungs were isolated for examination of expression of SARS-CoV-2-related receptors Angiotensin-Converting Enzyme 2 (ACE2) and others. Secondary analyses included circulating hormones and cytokines which have been shown to directly or indirectly impact on ACE2 expression and severity of viral infections. Changes in mRNA and protein expression were analyzed by RT-qPCR and western blotting and circulating hormones and cytokines were determined by ELISA and MESO QuickPlex. The PFAS mixture decreased Ace2 mRNA 2.5-fold in male mice (p < 0.0001), with no significant change observed in females. In addition, TMPRSS2, ANPEP, ENPEP and DPP4 (other genes implicated in COVID-19 infection) were modulated due to PFAS. Plasma testosterone, but not estrogen were strikingly decreased due to PFAS which corresponded to PFAS-mediated repression of 4 representative pulmonary AR target genes; hemoglobin, beta adult major chain (Hbb-b1), Ferrochelatase (Fech), Collagen Type XIV Alpha 1 Chain (Col14a1), 5'-Aminolevulinate Synthase 2 (Alas2). Finally, PFAS modulated circulating pro and anti-inflammatory mediators including IFN-γ (downregulated 3.0-fold in females; p = 0.0301, 2.1-fold in males; p = 0.0418) and IL-6 (upregulated 5.6-fold in males; p = 0.030, no change in females). In conclusion, our data indicate long term exposure to a PFAS mixture impacts mechanisms related to expression of ACE2 in the lung. This work provides a mechanistic rationale for important future studies of PFAS exposure and subsequent viral infection.

Combinatorial pathway disruption is a powerful approach to delineate metabolic impacts of endocrine disruptors

The prevalence of metabolic diseases, such as obesity, diabetes, metabolic syndrome and chronic liver diseases among others, has been rising for several years. Epidemiology and mechanistic (in vivo, in vitro and in silico) toxicology have recently provided compelling evidence implicating the chemical environment in the pathogenesis of these diseases. In this review, we will describe the biological processes that contribute to the development of metabolic diseases targeted by metabolic disruptors, and will propose an integrated pathophysiological vision of their effects on several organs. With regard to these pathomechanisms, we will discuss the needs, and the stakes of evolving the testing and assessment of endocrine disruptors to improve the prevention and management of metabolic diseases that have become a global epidemic since the end of last century.

Associations between serum perfluoroalkyl acid (PFAA) concentrations and health related biomarkers in firefighters

Firefighters who used aqueous film forming foam in the past have experienced elevated exposures to perfluoroalkyl acids (PFAAs). The objective of this study was to examine the associations between clinical chemistry endpoints and serum concentrations of perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorooctane sulfonate (PFOS) in firefighters. Multiple linear regression was used to assess relationships between PFAA serum concentrations and biochemical markers for cardiovascular disease, kidney-, liver- and thyroid function, in a cross-sectional survey of 783 firefighters with elevated levels of PFHxS, PFHpS and PFOS in relation to the most recently reported levels in the general Australian population. Linear logistic regression was used to assess the odds ratios for selected self-reported health outcomes. Repeated measures linear mixed models were further used to assess relationships between PFAAs and biomarkers for cardiovascular disease and kidney function longitudinally in a subset of the firefighters (n = 130) where serum measurements were available from two timepoints, five years apart. In the cross-sectional analysis, higher levels of all PFAAs were significantly associated with higher levels of biomarkers for cardiovascular disease (total-cholesterol, and LDL-cholesterol). For example, doubling in PFOS serum concentration were associated with increases in total cholesterol (β:0.111, 95% confidence interval (95%CI): 0.026, 0.195 mmol/L) and LDL-cholesterol (β: 0.104, 95%CI:0.03, 0.178 mmol/L). Doubling in PFOA concentration, despite not being elevated in the study population, were additionally positively associated with kidney function marker urate (e.g., β: 0.010, 95%CI; 0.004, 0.016 mmol/L) and thyroid function marker TSH (e.g., β: 0.087, 95%CI: 0.014, 0.161 mIU/L). PFAAs were not associated with any assessed self-reported health conditions. No significant relationships were observed in the longitudinal analysis. Findings support previous studies, particularly on the association between PFAAs and serum lipids.

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).

Review: Hydrothermal treatment of per- and polyfluoroalkyl substances (PFAS)

PER: and polyfluoroalkyl substances (PFAS) are a concerning and unique class of environmentally persistent contaminants with biotoxic effects. Decades of PFAS discharge into water and soil resulted in PFAS bioaccumulation in plants, animals, and humans. PFAS are very stable, and their treatment has become a global environmental challenge. Significant efforts have been made to achieve efficient and complete PFAS mineralization using existing and emerging technologies. Hydrothermal treatments in subcritical and supercritical water have emerged as promising end-of-life PFAS destruction technologies, attracting the attention of scholars, industry, and key stakeholders. This paper reviews the state-of-the-art research on the behavior of PFAS, PFAS precursors, PFAS alternatives, and PFAS-containing waste in hydrothermal processes, including the destruction and defluorination efficiency, the proposed reaction mechanisms, and the environmental impact of these treatments. Scientific literature shows that >99% degradation and >60% defluorination of PFAS can be achieved through subcritical and supercritical water processing. The limitations of current research are evaluated, special considerations are given to the challenges of technology maturation and scale-up from laboratory studies to large-scale industrial application, and potential future technological developments are proposed.

Co-exposure to perfluoroalkyl acids and heavy metals mixtures associated with impaired kidney function in adults: A community-based population study in China

BACKGROUND

Previous studies have separately linked either perfluoroalkyl acid (PFAA) or heavy metal exposure with kidney dysfunction. However, the relationships of co-exposure to PFAAs and heavy metals with kidney function are still unclear.

OBJECTIVES

To explore the associations between exposure to PFAAs and heavy metals mixtures and kidney function in adults.

METHODS

We conducted a cross-sectional community-based population study in Guangzhou, China, enrolling 1312 adults from November 2018 to August 2019. We quantified 13 PFAAs in serum and 14 heavy metals in plasma. We chose estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) as outcomes of interest. Distributed lag non-linear models (DLNMs) were used to check nonlinearity of individual pollutant with kidney function. Joint associations of pollutant mixtures on kidney function were assessed by Bayesian Kernel Machine Regression (BKMR) models. We further explored modification effects of gender.

RESULTS

Most individual PFAA and heavy metal were associated with declined kidney function in single-pollutant models. We also observed significant dose-response relationships of pollutant mixtures with reduced eGFR levels and increased odds of CKD in BKMR models. Perfluoroheptanesulfonic acid (PFHpS), arsenic (As) and strontium (Sr) were the predominant contributors among pollutant mixtures. A change in log PFHpS, As and Sr concentrations from the 25th to the 75th percentile were associated with a decrease in eGFR of -5.42 (95% confidence interval (CI): -6.86, -3.98), -2.14 (95% CI: -3.70, -0.58) and -1.87 (95% CI: -3.03, -0.72) mL/min/1.73 m², respectively, when other pollutants were at their median values. In addition, the observed associations were more obvious in females.

CONCLUSIONS

We provided new evidence that co-exposure to PFAAs and heavy metals mixtures was associated with reduced kidney function in adults and PFHpS, As and Sr appeared to be the major contributors. Further studies are warranted to confirm our findings and elucidate the underlying mechanisms.