Exposure to perfluoroalkyl substances (PFAS) and association with thyroid hormones in adolescent males

Per- and polyfluoroalkyl substances (PFAS), thyroid hormones, sexual hormones and pubertal development in adolescents residing in the neighborhood of a 3M factory

BACKGROUND

Near Antwerp a 3M factory has been active since 1971 emitting PFAS, mainly PFOS, in the local environment. Production of C8 compounds was stopped in 2002, production of other PFAS continued until 2024. This study aimed to examine the association between internal PFAS concentrations and thyroid hormones, sexual hormones, and pubertal development in adolescents living in the neighborhood of the factory.

METHODS

We measured PFAS in serum of 146 female and 139 male adolescents. For males sex hormones (LH, testosterone, estradiol, progesterone, inhibin B, FSH) and SHBG were measured in serum. For males and females we assessed serum thyroid hormone levels (TSH, T3, T4 and T3/T4) and pubertal development parameters self-assessed through a standardized questionnaire. Associations between PFAS concentrations and effect biomarkers/health effects were assessed through Generalized Estimating Equations (GEE), using linear models for continuous outcomes, logistic models for binary outcomes, and proportional odds models for ordinal outcomes.

RESULTS

For males LH, total and bioavailable testosterone showed significant negative associations with PFHxS and PFOA. LH and bioavailable testosterone also showed significant negative associations with other PFAS compounds. SHBG showed significant positive associations with PFDA, PFNA, PFHxS, PFOS and the sum of the linear forms of PFOS, PFOA, PFNA and PFHxS. Males' length and growth spurt showed significant negative associations with PFOS, PFOA and PFAS sum parameters and length and growth spurt separately also with other PFAS compounds. For females growth spurt showed significant negative association with PFOA and a significant positive association with PFOS(branched). For both males and females body hair development showed significant negative associations with PFHxS, and, for males and females separately also with other PFAS compounds. For females, breast development showed significant negative associations with PFOA, pubertal development scale showed significant negative associations with PFOA, PFHxS, PFOS(linear) and the sum of 4 PFAS. For males, TSH showed a significant negative association with PFDA and FT3 showed significant positive associations with PFOA, PFOA and PFNA. For females, FT3 showed a significant negative association with PFOS(branched).

CONCLUSION

We observed significant, consistent and biologically relevant associations of PFAS serum concentrations with sex hormone and SHBG levels in male adolescents. Moreover, a significant delay in physiological processes occurring in puberty was observed in females and males. Associations with thyroid hormones differed significantly by sex.

Non-linear associations between exposure to a mixture of per- and polyfluoroalkyl substances and thyroid hormone levels in Korean adults

BACKGROUND

This study investigated how exposure to per- and polyfluoroalkyl substances (PFAS) influence the levels of thyroid-stimulating hormone (TSH) and free thyroxine (fT4) and the risk of thyroid disease in euthyroid adults.

METHODS

A retrospective cohort study was conducted using data from 181 euthyroid Korean adults (59.4 ± 8.8 years, 33.1 % male) from the Korean Genome and Epidemiology Study. Serum concentrations of four PFAS (PFOA, PFOS, PFNA, and PFHxS) were measured using liquid chromatography-mass spectrometry, and a relative potency factor-based cumulative PFAS exposure (Cmix) was calculated. Linear regression and Bayesian Kernel Machine Regression (BKMR) were used to assess the associations between PFAS exposure and thyroid hormone levels. Cox regression analysis was conducted to assess the risk of thyroid disease during a 3.6 ± 1.3-year follow-up.

RESULTS

Serum PFOS levels were negatively correlated with TSH, showing a reverse J-shaped dose-response relationship. PFOS and PFNA exhibited inverse J-shaped positive associations with fT4. Mixed PFAS exposure (lnCmix) significantly reduced TSH levels in females (adjusted linear regression coefficient -0.56, 95 % CI -1.03 ∼ -0.09, p = 0.021) but had no significant effect on fT4. In the BKMR analysis, PFOA, PFOS, and PFNA were identified as factors that influenced TSH levels, exhibiting a non-significant decreasing pattern of TSH upon mixed exposure. During follow-up, mixed PFAS exposure increased the risk of thyroid disease (adjusted HR 9.53, 95 % CI 1.29-70.6, p = 0.027).

CONCLUSION

Mixed PFAS exposure decreases TSH levels, particularly in women, and increases the risk of thyroid disease. Further research is needed to assess the nonlinearity between exposure and outcomes, as well as to evaluate mixed exposures.

Health Impacts of Per- and Polyfluoroalkyl Substances (PFASs): A Comprehensive Review

Per- and polyfluoroalkyl substances (PFASs) are among the persistent organic pollutants characterized by their persistence in the environment, high mobility, and adverse impact not only on the ecosystem but also on human health. The biggest challenges in human biomonitoring are the low concentrations of PFASs in biological matrices and the presence of matrix interferents in samples. The combination of liquid chromatography with tandem mass spectrometry (LC-MS/MS) and solid-phase extraction (SPE) as a sample preparation technique appears to be the most suitable solution for achieving the desired selectivity and sensitivity in PFAS determination. The aim of this review is to describe possible sources of PFASs, their presence in various human matrices, analytical methods for determining PFASs in different biological matrices using various pretreatment techniques for complex samples, as well as adverse health risks associated with PFAS exposure. The most studied PFASs include PFOA and PFOS, which are most frequently detected in matrices such as plasma, serum, and breast milk. The average concentrations of PFOA range from 1.0 to 2.6 ng.mL-1 in plasma, 1.9 to 2.4 ng.mL-1 in serum, and 0.4 to 3.1 ng.mL-1 in breast milk. For PFOS, the average concentrations were 2.0-4.0 ng.mL-1, 3.7-4.6 ng.mL-1, and 3.6-4.8 ng.mL-1 for plasma, serum, and breast milk, respectively. The most significant health effects associated with exposure to long-chain PFASs (such as PFOA and PFOS) include lipid disorders, hypertension, diabetes mellitus, thyroid disorders, infertility, cancer, obesity, autism, neurodevelopmental issues, cardiovascular diseases, and kidney and liver disorders. It is of utmost importance to monitor PFAS exposure, predict their toxicity, and develop effective strategies to mitigate their potential effects on human health.

The Association Between Per- and Polyfluoroalkyl Substances Exposure and Thyroid Hormones in Men and Non-Pregnant Women: A Systematic Review and Meta-Analysis

Studies have shown that per- and polyfluoroalkyl substances (PFAS) may impact thyroid function in human health. While the consistency between PFAS exposure and thyroid health effects in pregnant women has been validated, the effects on men and non-pregnant women remains inconclusive. To address this, a meta-analysis was carried out in this paper, with 14 eligible studies retrieved from Embase, PubMed, and Web of Science that were published up to 2 June 2024, focusing on the relationship between PFAS exposure and its effect on thyroid hormone levels in the human body. The thyroid function indexes analyzed included thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The estimated value (β) and the corresponding confidence interval (95% CI) were extracted from the literature. A heterogeneity test was carried out, and the sensitivity analysis and publication bias of the studies were analyzed using Stata 18.0. The results revealed that in men and non-pregnant women, PFOA was positively correlated with FT3 (β = 0.011, 95% CI = 0.001, 0.02, I2 = 13.4). However, no significant associations were found between exposure to other PFAS and thyroid hormones. A subgroup analysis further indicated that the correlations between PFAS exposure and thyroid hormone levels were more significant in adolescents, in both America and Europe.

Research Progress in Current and Emerging Issues of PFASs' Global Impact: Long-Term Health Effects and Governance of Food Systems

Per- and polyfluoroalkyl substances (PFASs) are found everywhere, including food, cosmetics, and pharmaceuticals. This review introduces PFASs comprehensively, discussing their nature and identifying their interconnection with microplastics and their impacts on public health and the environment. The human cost of decades of delay, cover-ups, and mismanagement of PFASs and plastic waste is outlined and briefly explained. Following that, PFASs and long-term health effects are critically assessed. Risk assessment is then critically reviewed, mentioning different tools and models. Scientific research and health impacts in the United States of America are critically analyzed, taking into consideration the Center for Disease Control (CDC)'s PFAS Medical Studies and Guidelines. PFAS impact and activities studies around the world have focused on PFAS levels in food products and dietary intake in different countries such as China, European countries, USA and Australia. Moreover, PFASs in drinking water and food are outlined with regard to risks, mitigation, and regulatory needs, taking into account chemical contaminants in food and their impact on health and safety. Finally, PFAS impact and activities briefings specific to regions around the world are discussed, referring to Australia, Vietnam, Canada, Europe, the United States of America (USA), South America, and Africa. The PFAS crisis is a multifaceted issue, exacerbated by mismanagement, and it is discussed in the context of applying the following problem-solving analytical tools: the Domino Effect Model of accident causation, the Swiss Cheese Theory Model, and the Ishikawa Fish Bone Root Cause Analysis. Last but not least, PFASs' impacts on the Sustainable Development Goals (SDGs) of 2030 are rigorously discussed.

Per- and polyfluoroalkyl substances as persistent pollutants with metabolic and endocrine-disrupting impacts

The widespread use of per- and polyfluoroalkyl substances (PFASs), and their resistance to degradation, renders human exposure to them inevitable. PFAS exposure disturbs endocrine function, potentially affecting cognitive development in newborns through thyroid dysfunction during pregnancy. Recent studies reveal varying male and female reproductive toxicity across PFAS classes, with alternative analogs affecting sperm parameters and legacy PFASs correlating with conditions like endometriosis. Metabolically, PFASs exposure is linked to metabolic disorders, including obesity, type 2 diabetes mellitus (T2DM), dyslipidemia, and liver toxicity, particularly in early childhood. This review focuses on the endocrine-disrupting impact of PFASs, particularly on fertility, thyroid, and metabolic functions. We highlight the complexity of the PFAS issue, given the large number of molecules and their extremely diverse mixed effects.

Current trends and patterns of PFAS in agroecosystems and environment: A review

Per- and polyfluoroalkyl substances (PFASs) are one of the more well-known highly persistent organic pollutants with potential risks to agroecological systems. These compounds are of global concern due to their persistence and mobility, and they often lead to serious impacts on environmental, agricultural, and human health. In the past 20 years, the number of science publications on PFAS has risen; despite this, certain fundamental questions about PFAS occurrence, sources, mechanism of transport, and impacts on agroecosystems and the societies dependent on them are still open and evolving. There is a lack of systematic and comprehensive analysis of these concerns in agroecosystems. Therefore, we reviewed the current literature on PFAS with a focus on agroecosystems; our review suggests that PFASs are nearly ubiquitous in agricultural systems. We found the current research has limitations in analyzing PFAS in complex matrices because of their small size, distribution, and persistence within various environmental systems. There is consistency in the properties and composition of PFAS in and around agroecosystems, suggesting evidence of shared sources and similar components within different tropic levels. The introduction of new and varied sources of PFAS appear to be growing, adding to their residual accumulation in environmental matrices and leading to possible new types of chemical compounds that are difficult to assess accurately. This review determines existing research trends, understands mechanisms and incidence of PFAS within agroecosystems and their impact on human health, and thereby recommends further studies to remedy research gaps.

Associations of per- and polyfluoroalkyl substances and alternatives with subclinical hypothyroidism in children: A cross-sectional study in China

There is growing experimental and epidemiological evidence linking perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure to thyroid dysfunction; however, the association between PFAS and their alternatives to subclinical hypothyroidism in children remains to be elucidated. This study investigated the association between 30 PFASs and thyroid function using serum samples from 194 children (aged 3-17 years) who participated in the Zhejiang Human Biomonitoring Program. Various thyroid function indicators, including free triiodothyronine, free thyroxine (FT4), and thyrotropin, were tested, and subclinical hypothyroidism was diagnosed. Linear regression was employed to examine the associations between individual PFASs and thyroid hormone levels, and logistic regression was applied to assess their associations with subclinical hypothyroidism. The quantile g-computation (qgcomp) method was used to examine the combined and individual effects of PFAS mixtures on thyroid function. Both PFASs and their alternatives were associated with altered thyroid hormone levels and subclinical hypothyroidism. A higher level of perfluorohexanoic acid (PFHpA) was associated with decreased FT4 with a reduction of -0.028 pmol/L (95 % confidence interval [95 % CI]: -0.047, -0.008) per unit increase as well as increased odds of subclinical hypothyroidism (odds ratio [OR] = 1.95; 95 % CI: 1.11, 3.53). Moreover, a higher PFAS mixture was associated with elevated odds of subclinical hypothyroidism (OR = 3.72; 95 % CI: 1.08, 12.85), in which PFHpA, in conjunction with 6:2 chlorinated perfluoroalkyl ether sulfonic acid, accounted for the greatest proportion of the variance. These findings augment our understanding of the adverse effects of PFASs and their alternatives on thyroid homeostasis, underscoring the need for further epidemiological research.

Adverse outcome pathway for the neurotoxicity of Per- and polyfluoroalkyl substances: A systematic review

Per- and polyfluoroalkyl substances (PFAS) are endocrine disruptors with unambiguous neurotoxic effects. However, due to variability in experimental models, population characteristics, and molecular endpoints, the elucidation of mechanisms underlying PFAS-induced neurotoxicity remains incomplete. In this review, we utilized the adverse outcome pathway (AOP) framework, a comprehensive tool for evaluating toxicity across multiple biological levels (molecular, cellular, tissue and organ, individual, and population), to elucidate the mechanisms of neurotoxicity induced by PFAS. Based on 271 studies, the reactive oxygen species (ROS) generation emerged as the molecular initiating event 1 (MIE1). Subsequent key events (KEs) at the cellular level include oxidative stress, neuroinflammation, apoptosis, altered Ca2+ signal transduction, glutamate and dopamine signaling dyshomeostasis, and reduction of cholinergic and serotonin. These KEs culminate in synaptic dysfunction at organ and tissue levels. Further insights were offered into MIE2 and upstream KEs associated with altered thyroid hormone levels, contributing to synaptic dysfunction and hypomyelination at the organ and tissue levels. The inhibition of Na+/I- symporter (NIS) was identified as the MIE2, initiating a cascade of KEs at the cellular level, including altered thyroid hormone synthesis, thyroid hormone transporters, thyroid hormone metabolism, and binding with thyroid hormone receptors. All KEs ultimately result in adverse outcomes (AOs), including cognition and memory impairment, autism spectrum disorders, attention deficit hyperactivity disorders, and neuromotor development impairment. To our knowledge, this review represents the first comprehensive and systematic AOP analysis delineating the intricate mechanisms responsible for PFAS-induced neurotoxic effects, providing valuable insights for risk assessments and mitigation strategies against PFAS-related health hazards.

Targeted investigation of per- and polyfluoroalkyl substances from domestic cosmetics and personal care products in China and its implications for human exposure

Per- and polyfluoroalkyl substances (PFASs) are synthetic chemicals reported in daily supplies, and skin absorption is one of the routes for human exposure to PFASs. This study aims to evaluate the potential risk of PFASs exposure from cosmetics and personal care products in China. A random sampling of 44 domestic cosmetics and personal care products, summarized into 6 categories, was conducted to investigate the concentrations of 24 target PFASs. PFASs concentrations of 86.4 % products were lower than 100 ng/g, and 34.2 % products were lower than 10 ng/g. PFCAs and PAPs were dominant. Keywords of "wear-resistant" and "long-lasting" may indicate the presence of PFASs in products. Disabled PFOA, PFOS, and PFHxS were not detected. Notably, the presence of PFHxA should be of concern, and its detection frequency reached 59.1 %, with the maximum concentration of 1274.77 ng/g. Further, the daily exposure dose (DED) of ∑PFASs from skin exposure through cosmetics and personal care products was evaluated to be 3.01 ng/kg-bw/day, which wasn't negligible compared to the prescribed acceptable intake value. Conclusively, this study emphasizes that cosmetics and personal care products are important sources leading to the PFASs skin exposure and provides a basis for future regulation of PFASs as product additive.

Association between PFAS exposure and thyroid health: A systematic review and meta-analysis for adolescents, pregnant women, adults and toxicological evidence

A burgeoning body of epidemiological and toxicological evidence suggests that thyroid health may be significantly impacted by exposure to both long- and short-chain perfluoroalkyl substances (PFAS) compounds. We conducted a meta-analysis to examine the association between 16 PFAS compounds and five thyroid hormones (TSH, TT3, TT4, FT3, and FT4) in the serum of a pregnant women, adolescents, and adults. The dose-response relationship between some PFAS and thyroid hormones in different population subpopulation was found and the model was fitted. We also amalgamated data from 18 animal experiments with previously published in vitro studies to elucidate the toxicological mechanisms underlying the impact of PFAS on the thyroid gland. The results of the study showed that (a) both conventional and emerging PFAS compounds were identified in human samples and exhibited associations with thyroid health outcomes; (b) in animal studies, PFAS have been found to impact thyroid gland health through two primary mechanisms: by influencing the hypothalamic-pituitary-thyroid axis and by binding to thyroid receptors. This study provides a systematic description of the health effects and risk assessment associated with PFAS exposure on the thyroid gland. Furthermore, dose-response relationships were established through the Hill model in python.

Associations of per- and polyfluoroalkyl substances and heavy metals with blood lipid profiles in a representative sample of Korean adolescents

BACKGROUND

Previous studies on the associations of per- and polyfluoroalkyl substances (PFASs) and heavy metals with lipid profiles among adolescents have been scarce. We sought to investigate the associations of PFASs and heavy metals with blood lipid levels in a representative sample of Korean adolescents.

METHODS

Data from the Korean National Environmental Health Survey (2018-2020) were used. Concentrations of PFASs [perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid, perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDeA)], lead, and mercury were measured in serum, whole blood, and urine samples, respectively. Linear regression, Bayesian kernel machine regression (BKMR), and k-means clustering analyses were employed to evaluate the associations between pollutants and lipid levels.

RESULTS

In the linear regression analyses, PFOA levels were associated with higher low-density lipoprotein cholesterol (LDL-C) levels; PFOS with higher total cholesterol (TC) levels; PFNA with higher TC, LDL-C, and non-high-density lipoprotein cholesterol (non-HDL-C) levels; PFDeA with higher TC, LDL-C, non-HDL-C, and high-density lipoprotein cholesterol levels; and mercury with higher TC and non-HDL-C levels. The BKMR analysis revealed that the PFAS and heavy metal mixture was associated with higher LDL-C levels (1.8% increase in LDL-C at the 75th percentile of all PFAS and heavy metal concentrations compared to their median values, 95% credible interval: 0.5, 3.1), primarily driven by the effect of PFDeA. Compared to individuals in the low pollutant exposure cluster (geometric mean levels of PFOA, PFOS, PFHxS, PFNA, PFDeA, lead, and mercury were 2.7 μg/L, 6.2 μg/L, 1.6 μg/L, 0.7 μg/L, 0.4 μg/L, 0.8 μg/dL, and 0.3 μg/L, respectively), those in the high pollutant exposure cluster (5.1 μg/L, 10.7 μg/L, 3.7 μg/L, 1.3 μg/L, 0.6 μg/L, 0.9 μg/dL, and 0.4 μg/L, respectively) demonstrated higher TC levels (2.5% increase in TC, 95% confidence interval: 0.1, 5.0) in the k-means clustering analysis.

CONCLUSION

Due to the limitations of this study, such as its cross-sectional design, these results should be interpreted cautiously and confirmed in future studies before drawing implications for public health strategies aimed at promoting health during adolescence and later in life.

Association between exposure to perfluoroalkyl substances (PFAS) and endometriosis in the ENDEA case-control study

BACKGROUND

Perfluoroalkyl substances (PFAS) are environmental contaminants present in a wide range of consumer products and frequently detected in drinking water. They have been linked to adverse reproductive health outcomes in women, but there is limited human evidence on the association of PFAS exposure with endometriosis.

OBJECTIVE/AIM

To explore the association between plasma concentrations of several PFAS, considered individually and as a mixture, and the risk of endometriosis in women of childbearing age.

METHODS

Between 2018 and 2020, 42 patients with endometriosis and 90 controls undergoing abdominal surgery were recruited at two public hospitals in Granada, Spain. The presence or absence of endometriosis was ascertained by laparoscopic inspection of the pelvis and biopsy of suspected lesions (histological diagnosis). Concentrations of 10 PFAS were quantified in plasma samples from participants. Unconditional logistic regression was employed to examine associations of individual PFAS and summed concentrations of short (∑SC) and long-chain (∑LC) PFAS with odds of endometriosis, and quantile g-computation was used to assess their mixture effect.

RESULTS

In models adjusted for age, schooling, and parity, perfluorotridecanoic acid (PFTrDA) was associated with higher odds of endometriosis (odds ratio [OR] = 1.74; 95 % CI = 1.11-2.73 per 2-fold increase in plasma concentrations), while marginally significant associations were found for perfluorohexane sulfonate (PFHxS) (OR = 1.45, 95 % CI = 0.94-2.21) and ∑SC PFAS (OR = 1.48; 95 % CI = 0.96-2.30). No associations were found for the remaining PFAS. The PFAS mixture was non-significantly associated with 1.7-fold higher odds of endometriosis (95 % CI = 0.73-3.80), with perfluorononanoic acid (PFNA), PFHxS, and PFTrDA being the major contributors to this effect.

CONCLUSIONS

These findings suggest that exposure to certain PFAS may increase the odds of endometriosis. However, given the modest sample size, further studies are warranted to verify these results.

Possible mechanisms for adverse effects on zebrafish sperm and testes associated with low-level chronic PFOA exposure

Perfluorooctanoic acid (PFOA), which is widely used during the manufacturing of fluoropolymer coatings and polytetrafluoroethylene, is now a widespread pollutant in the environment and within the human body. This study used zebrafish, an aquatic model species, to investigate how low levels of chronic PFOA exposure affect the reproductive system. The results of the experiments in which zebrafish were exposed to 414 ng/L or 4140 ng/L for 60 days showed a variety of adverse effects on testicular tissue and sperm, including dose-dependent changes in plasma estradiol and testosterone levels, various sperm malformations, decreased sperm motility and concentration, and PFOA-induced oxidative stress and testicular damage with increased rates of apoptosis. In addition, offspring of the zebrafish that had been exposed to PFOA were characterized by increased malformation and mortality. Subsequent transcriptional analyses of the male gonads revealed the significant activation of oxidative stress bioprocesses and immuno-inflammatory signaling pathways, along with the dysregulation of reproductive bioprocesses. In conclusion, low-level chronic exposure to PFOA affects both the reproductive performance of adults and the development of offspring; the mechanisms for these adverse effects involve alterations in several molecular pathways that may be involved in PFOA-induced oxidative stress and reproductive abnormalities. The presented data can be used to assess the ecotoxicity of PFOA to the male reproductive system at environmentally-relevant concentrations.

Thyrotoxic Effects of Mixed Exposure to Perfluorinated Compounds: Integrating Population-Based, Toxicogenomic, Animal, and Cellular Evidence to Elucidate Molecular Mechanisms and Identify Potential Effector Targets

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are emerging environmental endocrine disruptors that may adversely affect the human endocrine system, particularly the thyroid gland, the largest endocrine gland in the human body. An epidemiologic survey was conducted involving 318 community residents in Shanghai, China, to assess PFAS exposure levels. The relationship between PFAS exposure and five thyroid function indicators was analyzed using Bayesian Kernel Regression (BKMR) and Weighted Quantile Sum Regression (WQS). Ten effector genes related to PFAS and thyroid diseases were identified through the Comparative Toxicogenomics Database (CTD) for bioinformatics analysis and pathways involved were explored through mediation analysis. In vivo validation of these effector genes was conducted using PCR, complemented by in vitro cellular experiments involving transcriptome sequencing and the construction of animal models to simulate mixed PFAS exposure in the general population. Mixed PFAS exposure was found to impact thyroid health primarily through pathways related to lipid metabolism in toxicogenomic studies and resulted in the upregulation of key genes associated with lipid metabolism in animal models. Our results demonstrate that PFAS exposure could affect the expression of lipid metabolism pathways through the modulation of transcription factors, contributing to the development of thyroid disease.

Environmental iodine as a natural iodine intake in humans and environmental pollution index: a scientometric and updated mini review

Although almost a third of the world's population is exposed to iodine deficiency (ID), and supplementation programs such as enriching table salt have been carried out or are being carried out at the global and national level, in many regions of the world, people are facing an increase in iodine intake, which is mainly due to the presence of large amounts of iodine in water, soil, agricultural products, or high consumption of seafood. Published articles were indexed in the Scopus database (from 2000 to 1 April 2023) were reviewed and analyzed by VOSviewer software. The results showed the growing interest of researchers over the last 20 years in environmental iodine intake. The results of this study can have a significant impact on the planning and policy-making of relevant officials and communities to supply the needed iodine.

Sex and obesity influence the relationship between perfluoroalkyl substances and lean body mass: NHANES 2011-2018

Objective

Polyfluoroalkyl substances (PFAS) are known endocrine disruptors, that have been the subject of limited research regarding their impact on human lean body mass. The aim of this study was to investigate the effects of PFAS exposure on lean body mass.

Methods

We performed a cross-sectional data analysis involving 1022 adolescents and 3274 adults from the National Health and Nutrition Examination Survey (NHANES) 2011-2018, whose lean body mass was measured by dual-energy X-ray absorptiometry. The lean mass index (LMI) was calculated as lean body mass dividing by the square of height. The association between PFAS and LMI was examined through a multivariate-adjusted weighted generalized linear model. Moreover, weighted quantile sum (WQS) regression models were employed to futher examine the relationship between the mixture of PFAS and LMI.

Results

Regression analyses revealed an inverse correlation between PFAS exposure and LMI after adjusting for potential covariates. Adults with higher serum PFAS concentrations manifested a reduction in whole LMI ( β  = -0.193, 95 % confidence interval (CI): -0.325 to -0.06). Notably, this correlation was particularly significant in adult females and individuals with obesity, and it was observed across diverse anatomical regions, including lower limbs, right arm, trunk, and whole lean body mass. In adult females, the association between PFAS and whole LMI was statistically significant ( β  = -0.294, 95 % CI: -0.495 to -0.094), and a similar trend was found in obese individuals ( β  = -0.512, 95 % CI: -0.762 to -0.261). WQS regression analyses supported the results obtained from weighted linear regression analyses.

Conclusions

Our study suggests that exposure to PFAS, whether individually or in combination, is associated with decreased lean body mass in specific body areas, with sex and obesity serving as major influencing factors.

Albumin Proteins as Delivery Vehicles for PFAS Contaminants into Respiratory Membranes

Poly- and perfluoroalkyl substances (PFAS) are a family of chemicals that have been used in a wide range of commercial products. While their use is declining, the prevalence of PFAS, combined with their chemical longevity, ensures that detectable levels will remain in the environment for years to come. As such, there is a pressing need to understand how PFAS contaminants interact with other elements of the human exposome and the consequences of these interactions for human health. Using serum albumin as a model system, we show that proteins can bind PFAS contaminants and facilitate their incorporation into model pulmonary surfactant systems and lipid bilayers. Protein-mediated PFAS delivery significantly altered the structure and function of both model membrane systems, potentially contributing to respiratory dysfunction and airway diseases in vivo. These results provide valuable insights into the synergistic interaction between PFAS contaminants and other elements of the human exposome and their potential consequences for human health.

Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies

BACKGROUND

Perfluoroalkyl substances (PFAS) and phthalates are synthetic chemicals widely used in various types of consumer products. There is epidemiological and experimental evidence that PFAS and phthalates may alter thyroid hormone levels; however, studies in children and adolescents are limited.

AIM

To investigate the association of exposure to PFAS and phthalate with serum levels of thyroid hormones in European adolescents.

METHODS

A cross-sectional study was conducted in 406 female and 327 male adolescents (14-17 years) from Belgium, Slovakia, and Spain participating in the Aligned Studies of the HBM4EU Project (FLEHS IV, PCB cohort, and BEA, respectively). Concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were measured in sera from study participants, and urinary metabolites of six phthalates (DEP, DiBP, DnBP, BBzP, DEHP, and DiNP) and the non-phthalate plasticizer DINCH® were quantified in spot urine samples. Associations were assessed with linear regression and g-computational models for mixtures. Effect modification by sex was examined.

RESULTS

In females, serum PFOA and the PFAS mixture concentrations were associated with lower FT4 and higher FT3 levels; MEP and the sums of DEHP, DiNP, and DINCH® metabolites (∑DEHP, ∑DiNP, and ∑DINCH) were associated with higher FT4; ∑DEHP with lower FT3; and the phthalate/DINCH® metabolite mixture with higher FT4 and lower FT3. In males, PFOA was associated with lower FT4 and the PFAS mixture with higher TSH levels and lower FT4/TSH ratio; MEP and ∑DiNP were associated with higher FT4; and MBzP, ∑DEHP, and the phthalate/DINCH® metabolite mixture with lower TSH and higher FT4/TSH. PFOA, mono-(2-ethyl-5-hydroxyhexyl) phthalate (OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (oxo-MEHP), and monocarboxyoctyl phthalate (MCOP) made the greatest contribution to the mixture effect.

CONCLUSIONS

Results suggest that exposure to PFAS and phthalates is associated with sex-specific differences in thyroid hormone levels in adolescents.