The concentration of several perfluoroalkyl acids in serum appears to be reduced by dietary fiber

Diet quality in relation to serum perfluoroalkyl substance concentrations in Canadian preadolescents

BACKGROUND

Exposure to perfluoroalkyl substances (PFAS) is concerning because some of these chemicals are associated with health effects. Preadolescents eat more food per body weight and may be more affected by substances in food compared to adults.

OBJECTIVE

Estimate how diet quality and nutrients are associated with concurrently measured PFAS concentrations in Canadian preadolescents.

METHODS

Using data from 157 participants (7-11 years) in a Maternal-Infant Research on Environmental Chemicals follow-up study (2018-2021), we analyzed serum concentrations of 9 PFAS, and derived 2019-Healthy Eating Food Index (HEFI-2019) scores and nutrient intakes from 24-h diet recalls. We used multivariable linear regression to estimate cross-sectional associations between diet and serum PFAS concentrations.

RESULTS

Saturated fat consumption was associated with higher serum perfluorooctanesulfonic acid (PFOS) concentrations. The fruits and vegetables score was associated with higher perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA); similar associations appeared with the HEFI-2019 total score. Percentage of energy intake (%E) from protein was associated with lower perfluorooctanoic acid (PFOA), PFOS, and perfluorohexanesulphonic acid (PFHxS) while %E from fat was associated with higher PFDA and PFOS. Fiber and iron intakes were associated with higher PFHxS. Vitamin D intake was associated with lower PFNA.

CONCLUSIONS

We observed some associations between diet and PFAS. Our findings may be partially explained by toxicokinetics and PFAS presence in Canadian food systems. However, our interpretation is hindered by lack of temporality and potential confounding. Additional investigations which integrate food systems information paired with PFAS concentrations from food and biomonitoring are required.

Degree of food processing and serum poly- and perfluoroalkyl substance concentrations in the US National Health and Nutrition Examination Survey, 2003-2018

BACKGROUND

Ultra-processed foods account for >50% of total energy consumed among U.S. individuals and may be a source of poly- and perfluoroalkyl substances (PFAS) exposure - chemicals linked with cancer/cardiometabolic disorders.

OBJECTIVE

To evaluate associations between degree of food processing and PFAS exposure.

METHODS

Serum concentrations of seven PFAS were analyzed in 11,530 individuals ≥12-years-old from the U.S. National Health and Nutrition Examination Survey (2003-2018). We averaged responses from two 24-h dietary recalls to calculate relative energy intakes of unprocessed/minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods using the Nova food classification system. We estimated percent differences in concentrations (β; PFAS with ≥70% detection) or odds ratios of detection (OR; PFAS with <70% detection) using linear or logistic regression, respectively. We explored associations stratified by cycle, life stage, sex, body mass index, race/ethnicity, and poverty/income ratio.

RESULTS

Each 10% increase in ultra-processed food intake was associated with higher serum perfluorohexanesulfonic acid (PFHxS; β: 1.40; 95%CI: -0.12, 2.94), but lower perfluorodecanoic acid (PFDA; β: -4.41; 95%CI: -5.55, -3.26) and perfluoroundecanoic acid (PFUnDA; OR: 0.82; 95%CI: 0.79, 0.86) concentrations. Positive associations between ultra-processed foods and PFHxS were driven by adolescents and under-/normal weight individuals. Additionally, each 10% increase in unprocessed/minimally processed food intake was associated with lower perfluorooctanoic acid (PFOA; β: -1.10; 95%CI: -2.38, 0.20) and PFHxS (β: -1.50; 95%CI: -3.03, 0.06), but higher perfluorononanoic acid (PFNA; β: 1.71; 95%CI: 0.24, 3.21), PFDA (β: 5.33; 95%CI: 3.78, 6.90), and PFUnDA (OR: 1.22; 95%CI: 1.16, 1.27). Positive and negative associations of unprocessed/minimally processed foods and ultra-processed foods, respectively, with PFDA and PFUnDA were strongest in recent survey cycles, males, and non-Hispanic Asians.

SIGNIFICANCE

Unprocessed/minimally processed foods, more than ultra-processed, were associated with serum PFAS concentrations. Efforts should focus on eliminating PFAS from multiple parts of the food chain.

Prenatal PFAS exposure and outcomes related to maternal gut microbiome composition in later pregnancy

The composition of the gut microbiome is dependent on factors including diet, lifestyle, and exposure to environmental chemicals, and has implications for human health. Per- and polyfluoroalkyl substances (PFAS), a class of man-made chemicals that have nonstick and flame-retardant properties may impact on gut microbiome composition. Our objective was to elucidate links between PFAS and maternal gut microbiome composition in two geographically diverse sites of the Environmental Influences on Child Health Outcomes program. The present analysis includes participants in the Atlanta African American Maternal Child Cohort; ATL AA and a predominately non-Hispanic White subsample of the Michigan Archive for Research on Child Health Cohort; MARCH with serum or plasma PFAS concentrations measured in early or late pregnancy and 16s rRNA sequencing from maternal gut microbiome samples available primarily in later pregnancy (2nd-3rd trimester). Linear regression models tested associations between prenatal PFAS levels (separately for the 1st/3rd trimesters) and measures of alpha diversity, bacterial composition differences, and differential taxonomic abundance. Bayesian Kernel Machine Regression and Elastic net regression mixture modeling were also incorporated. In both cohorts, multiple PFAS were significantly associated with the relative abundance of specific microbiome taxa even after adjustment for covariates including maternal diet, age, race, BMI, and smoking; A total of 16 significant family-level associations were identified for ATL AA (e.g., PFOA with Clostridiaceae; natural log fold change = 0.94) and 13 significant family-level associations identified for MARCH e.g., PFOS with Desulfovibrionaceae; natural log fold change = -1.53 (pFDR<0.05), but similarities between cohorts were lacking. Mixture analyses did not identify interactive or combined effects but did provide modest evidence of inclusion of individual PFAS in beta diversity models in both cohorts. In 2 distinct cohorts, there were significant associations between prenatal PFAS and the relative abundance of several bacterial taxa, but these differences were cohort-specific. This work suggests that PFAS may modulate the gut microbiome during pregnancy.

Per- and poly-fluoroalkyl substances (PFAS) in circulation in a Canadian population: their association with serum-liver enzyme biomarkers and piloting a novel method to reduce serum-PFAS

Extensive use of per- and polyfluoroalkyl substances (PFAS) has resulted in their ubiquitous presence in human blood. PFAS exposures have been associated with multiple adverse human health effects. Biomonitoring studies have focused on long-chain PFASs, but these are being replaced by short-chain PFASs or with alternate PFAS chemistries (or replacement chemistries such as GenX), resulting in changes in human exposures with time. Here, we take advantage of serum samples collected as part of a clinical trial testing the efficacy of a dietary fiber intervention to reduce serum cholesterol to investigate exposure to PFASs in Canadian participants. Serum samples were collected from 72 participants (adult males with elevated cholesterol) in 2019-2020 at baseline and after 4 weeks of the intervention and were analyzed for 17 PFASs. The highest geometric mean serum concentrations of PFAS measured at baseline corresponded to PFOSA (7.1 ng/ml), PFOS (4.2, ng/ml), PFOA (1.8 ng/ml) and PFHxS (1.3 ng/ml). Four long-chain PFASs (PFOA, PFOS, PFOSA and PFHxS) and two short-chain PFASs (PFBA, PFHxA) were detected in 100% of participants. GenX was detected in 71% of participants. Analyses of associations between serum-PFAS concentrations and biomarkers of adverse health outcomes showed the PFBA, PFHxA, PFDA and PFOSA were associated with higher serum gamma-glutamyl transferase concentrations but not with measures of serum-total or low-density lipoprotein cholesterol. Comparison of PFAS concentrations at baseline and after a 4-week follow-up showed that the total PFAS detected decreased in both the control and cholesterol intervention groups. However, the suite of long-chain PFASs of concern identified by the United States National Academies of Sciences, Engineering, and Medicine, significantly decreased only in the cholesterol intervention group. This observation suggests that a sustained dietary fiber intervention may reduce long-chain PFAS body burden, but future intervention studies need to control for PFAS exposure sources and extend the dietary supplement intake beyond 4 weeks. Overall, the results show that exposures to short-chain and replacement chemistry PFASs are common in this Canadian population.

An oat fiber intervention for reducing PFAS body burden: A pilot study in male C57Bl/6 J mice

Perfluoroalkyl substances (PFAS) are a major public health concern, in part because several PFAS have elimination half-lives on the order of years and are associated with adverse health outcomes. While PFAS can be transported into bile, their efficient reuptake by intestinal transporter proteins results in minimal fecal elimination. Here, we tested the hypothesis that consumption of oat β-glucan, a dietary supplement known to disrupt the enterohepatic recirculation of bile acids, will reduce PFAS body burdens. Male C57Bl/6 J mice were fed diets based on the "What we eat in America" analysis that were supplemented with inulin or oat β-glucan and exposed via drinking water to a seven PFAS mixture (PFHpA, PFOA, PFNA, Nafion Byproduct-2, PFHxS and PFOS) for 6 weeks. One cohort of mice was euthanized at the end of the exposure, and one cohort continued on the experimental diets for 4 more weeks without additional PFAS exposure. The β-glucan fed mice drank significantly more water than the inulin fed mice, resulting in a significantly higher dose of PFAS. Relative to overall exposure, we observed lower serum concentration trends (p < 0.1) in β-glucan fed mice for PFHpA, PFOA and PFOS. Additionally, β-glucan fed mice had lower adipose:body weight ratios and liver and jejunum triglyceride concentrations. Hepatic mRNA expression of Cyp4a10, Cyp2b10 and Cyp3a11 were elevated in PFAS exposed mice, with only the expression of Cyp3a11 decreasing following depuration. This pilot study generates support for the hypothesis that oat β-glucan supplementation can reduce PFAS body burdens and stimulate healthful effects on lipid homeostasis.

Sex specificity in associations between exposure to a mixture of per and poly-fluoroalkyl substances and anxiety among US adults

BACKGROUND

Exposure to per and poly-fluoroalkyl substances (PFAS) is suggested to interfere with the central nervous system that may affect mental health. Studies on the relationships between exposure to PFAS mixtures and anxiety in humans are rare. This study aimed to evaluate the associations between single and combined exposure to PFAS and anxiety among adults.

METHODS

Data were extracted from the National Health and Nutrition Examination Survey (NHANES, 2007-2012). Six serum PFAS concentrations were accessed including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), PFOS (perfluorooctanesulfonic acid), PFHxS (perfluorohexane sulfonate), PFDA (perfluorodecanoic acid), Me-PFOSA-AcOH (2-(N-methylperfluorooctanesulfonamide) acetic acid). The anxiety state was defined through the questionnaire responses of the participants. Weighted logistics regression was used to calculate their odds ratio (OR) and corresponding confidence interval (95% CI) that assessed the relationship between PFAS exposure and anxiety. Moreover, Two different statistical methods including quantile-based g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) were employed to investigate the overall effects of PFAS mixtures on anxiety.

RESULTS

The effects of specific PFAS exposure on anxiety varied by sex. In male participants, one-unit increase in PFDA (OR = 0.62; 95%CI: 0.44, 0.88), PFOA (OR = 0.60; 95%CI: 0.41, 0.87), PFNA (OR = 0.68; 95%CI: 0.46, 0.96) concentrations were inversely linked to anxiety. In female participants, a one-unit increase in PFOA (OR = 1.50; 95%CI: 1.05, 2.14) concentration was associated with anxiety. Analysis of Qgcomp demonstrated that PFAS mixtures were negatively associated with anxiety in males (OR = 0.85; 95%CI: 0.74, 0.99), and were positively associated with anxiety in females(OR = 1.16; 95%CI: 1.01, 1.33). Analysis of BKMR suggested that PFAS mixtures were negatively associated with anxiety in the males, while its associations with anxiety were positive in the females.

IMPACT

Although a growing number of studies have focused on the relationship between PFAS and anxiety, most have been performed based on animal observations rather than human populations, and the combined effects of PFAS mixtures on anxiety have not been evaluated. To address these gaps, this study first explored the associations between individual PFAS and PFAS mixture exposures and anxiety among US adults. Using data from the National Health and Nutrition Examination Survey, we demonstrated that co-exposure to a mixture of PFAS was negatively associated with anxiety in males, and its association was contrary in females.

Concentrations and exposure risks of per- and polyfluoroalkyl substances in human milk from Southern China during the first 400 days of lactation

Per- and polyfluoroalkyl substances (PFASs) pose significant health risks, particularly for infants who are highly susceptible during early life. Although several studies have reported PFASs concentrations and exposure risks in human milk in China, they typically cover only up to 3 months postpartum, failing to align with the WHO recommendation of continued breastfeeding to 2 years of age. Therefore, this study aimed to address this gap by investigating the concentrations and exposure risks of legacy and emerging PFASs in human milk collected during the first 400 days postpartum from Southern China. We detected all the target 23 PFASs compounds, with 22 PFASs found in more than half of the samples. The median concentration of total PFASs in human milk was 151 ng/L, with PFOA, PFOS, 6:2 Cl-PFESA, and 8:2 Cl-PFESA being the most abundant. Total PFASs concentration peaked within the first 45 days postpartum (median, 154 ng/L), significantly higher than that at 200 -240 days (median, 145 ng/L) and 300 -400 days postpartum (median, 148 ng/L). PFBA, PFOA, PFNA, ADONA and PFOS also exhibited similar lactation patterns. Additionally, we calculated the estimated daily intakes (EDIs) of total PFASs for infants by multiplying their concentration in human milk by daily milk consumption, and dividing by body weight. The median EDIs of PFASs were 19.0, 10.2, and 9.03 ng/kg bw/d at 0 -45 days, 200 -240 days, and 300 -400 days postpartum, respectively. The corresponding median hazard quotients of PFASs for infants were 11.2, 5.43, and 5.23, respectively. These findings suggest persistent risks of PFASs exposure for infants through human milk during the first 400 days postpartum. However, breastfeeding remains the optimal choice due to its significant health benefits. It is crucial to reduce human milk PFASs concentrations by minimizing dietary and environmental exposures among lactating women.

Efficient photocatalytic decomposition of PFOA over BiOI1-x with low power LED light

In recent years, the academic community has shown significant interest in per- or polyfluoroalkyl compounds (PFAS) due to their challenging degradation and potential health risks. Photocatalysis has been investigated for PFAS decomposition due to its environmentally friendly nature. In this study, BiOI with abundant iodine vacancies was synthesized through solvothermal and calcination methods (referred to as BiOI1-x), and was used for PFAS degradation with a low power UV light source. Compared to pure BiOI, BIOI1-x showed higher photocatalytic activity towards PFOA (perfluorooctanoic acid). Within 5 h under 5 W LED light irradiation, the degradation rate of PFOA reached 51.9 % with BiOI1-x calcined at 440 °C (No significant degradation of PFAS was observed with pure BiOI). Capture experiments, electron paramagnetic resonance spectroscopy, and electrochemical experiments revealed that the main active species in the system were photogenerated holes, followed by hydroxyl radicals. Furthermore, the presence of iodine vacancies significantly improved the efficiency of charge carrier separation and enhanced the photocatalytic performance. Finally, a hypothetical degradation pathway for PFOA in this system was suggested. This study achieved efficient degradation of PFAS under low power LED light (5 W), emphasizing its significant practical importance in terms of energy conservation.

Diet rich in soluble dietary fibres increases excretion of perfluorooctane sulfonic acid (PFOS) in male Sprague-Dawley rats

Perfluorooctane sulfonic acid (PFOS) belongs to a large group of anthropogenic compounds with high persistency named per- and polyfluorinated substances (PFAS). Widespread use from industry to household appliances and food-contact materials contributes to PFAS exposure with food as the primary source. Association studies suggest that vegetables and fibre rich diet may reduce PFOS levels in humans, but experimental data remain limited. Here, we investigated PFOS uptake and wash-out after seven days of PFOS (3 mg/kg/day) in two groups of rats (N = 12 per group) fed diets either high (HF) or low (LF) in soluble dietary fibres. Two control groups (N = 12/group) were fed the same diets without PFOS. Changes in pH and transit time were monitored alongside intestinal and faecal microbiota composition. We quantified systemic and excreted, linear and branched PFOS. Results revealed significantly lower pH and faster intestinal transit in the HF groups. Importantly, HF rats had lower serum PFOS concentrations and higher PFOS concentrations in caecal content and faeces, indicating a more efficient excretion on the fibre rich diet. In both dietary groups, PFOS affected the gut microbiota composition. Our results suggest that a diet rich in soluble dietary fibres accelerates excretion of PFOS and lowers PFOS concentration in serum.

Association between the dietary inflammatory index and serum perfluoroalkyl and polyfluoroalkyl substance concentrations: evidence from NANHES 2007-2018

Diet is an important source of perfluoroalkyl and polyfluoroalkyl substance (PFAS) exposure, and the dietary inflammatory index (DII) is a tool used to assess the inflammatory potential of an individual's diet. However, limited research has explored the association between the DII and PFAS exposure in humans. This study is the first to analyze the association between the five PFASs and DII using the National Health and Nutrition Examination Survey (NHANES) 2007-2018 database. Additionally, we assessed the interaction between the DII and PFASs regarding oxidative stress and inflammatory markers, including alkaline phosphatase, albumin, neutrophil count, lymphocyte count, total bilirubin, and serum iron based on a previous study. A series of covariates were included in the analysis to reduce the confounding bias. The study included 7773 and 5933 participants based on the different models. The DII was significantly associated with serum perfluorooctanoic acid, perfluorononanoic acid, perfluorooctane sulfonic acid, and sum-PFAS. Some of the food parameters used to calculate the DII also showed associations with special PFAS serum concentrations. Specifically, dietary fiber, n-3 polyunsaturated fatty acids, energy intake, and vitamin D were associated with more than three PFASs. Higher DII levels in participants were linked to a more significant association between bilirubin (the interaction P-value is not significant), alkaline phosphatase, serum iron, neutrophil counts, and some PFASs. In conclusion, this study clarified the association between the three PFASs and DII, highlighting the diverse effects of PFASs on oxidative stress and inflammatory markers across different DII levels.

Association of diet with per- and polyfluoroalkyl substances in plasma and human milk in the New Hampshire Birth Cohort Study

Per- and polyfluoroalkyl substances (PFAS) are related to various adverse health outcomes, and food is a common source of PFAS exposure. Dietary sources of PFAS have not been adequately explored among U.S. pregnant individuals. We examined associations of dietary factors during pregnancy with PFAS concentrations in maternal plasma and human milk in the New Hampshire Birth Cohort Study. PFAS concentrations, including perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorodecanoate (PFDA), were measured in maternal plasma collected at ∼28 gestational weeks and human milk collected at ∼6 postpartum weeks. Sociodemographic, lifestyle and reproductive factors were collected from prenatal questionnaires and diet from food frequency questionnaires at ∼28 gestational weeks. We used adaptive elastic net (AENET) to identify important dietary variables for PFAS concentrations. We used multivariable linear regression to assess associations of dietary variables selected by AENET models with PFAS concentrations. Models were adjusted for sociodemographic, lifestyle, and reproductive factors, as well as gestational week of blood sample collection (plasma PFAS), postpartum week of milk sample collection (milk PFAS), and enrollment year. A higher intake of fish/seafood, eggs, coffee, or white rice during pregnancy was associated with higher plasma or milk PFAS concentrations. For example, every 1 standard deviation (SD) servings/day increase in egg intake during pregnancy was associated with 4.4 % (95 % CI: 0.6, 8.4), 3.3 % (0.1, 6.7), and 10.3 % (5.6, 15.2) higher plasma PFOS, PFOA, and PFDA concentrations respectively. Similarly, every 1 SD servings/day increase in white rice intake during pregnancy was associated with 7.5 % (95 % CI: -0.2, 15.8) and 12.4 % (4.8, 20.5) greater milk PFOS and PFOA concentrations, respectively. Our study suggests that certain dietary factors during pregnancy may contribute to higher PFAS concentrations in maternal plasma and human milk, which could inform interventions to reduce PFAS exposure for both birthing people and offspring.

Per- and polyfluoroalkyl substances and bone mineral content in early adolescence: Modification by diet and physical activity

BACKGROUND

Per- and polyfluoroalkyl substance (PFAS) exposures may negatively impact bone mineral accrual, but little is known about potential mitigators of this relation. We assessed whether associations of PFAS and their mixture with bone mineral content (BMC) in adolescence were modified by diet and physical activity.

METHODS

We included 197 adolescents enrolled in a prospective pregnancy and birth cohort in Cincinnati, Ohio (2003-2006). At age 12 years, we collected serum for PFAS measurements and used dual-energy x-ray absorptiometry to measure BMC. We calculated dietary calcium intake and Health Eating Index (HEI) scores from repeated 24-h dietary recalls, physical activity scores using the Physical Activity Questionnaire for Older Children (PAQ-C), and average moderate to vigorous physical activity (MVPA) based on accelerometry. We estimated covariate-adjusted differences in BMC z-scores per interquartile range (IQR) increase of individual PFAS concentrations using linear regression and per simultaneous IQR increase in all four PFAS using g-computation. We evaluated effect measure modification (EMM) using interaction terms between each modifier and PFAS.

RESULTS

Higher serum perfluorooctanoic acid, perfluorooctanesulfonic acid, and perfluorononanoic acid concentrations and the PFAS mixture were associated with lower BMC z-scores. An IQR increase in all PFAS was associated with a 0.27 (-0.54, 0.01) lower distal radius BMC z-score. Associations with lower BMC were generally stronger among adolescents classified as < median for calcium intake, HEI scores, or MVPA compared to those ≥ median. The difference in distal radius BMC z-score per IQR increase in all PFAS was -0.38 (-0.72, -0.04) for those with

CONCLUSION

Healthy, calcium-rich diets and higher intensity physical activity may mitigate the adverse impact of PFAS on adolescent bone health.

Collapse

Key Words

• Adolescent health
• Bone mineral content
• Calcium
• Diet
• Perfluoroalkyl substances
• Physical activity

Collapse

MESH Headings

• Humans
• Female
• Fluorocarbons/blood
• Male
• Bone Density/drug effects
• Child
• Adolescent
• Diet
• Environmental Pollutants/blood
• Prospective Studies
• Ohio
• Alkanesulfonic Acids/blood
• Exercise
• Motor Activity/drug effects

Collapse

Grants

• R01 ES030078 NIEHS NIH HHS
• R01 ES033252 NIEHS NIH HHS
• R01 ES027224 NIEHS NIH HHS
• L40 ES032257 NIEHS NIH HHS
• P01 ES011261 NIEHS NIH HHS
• R01 ES032836 NIEHS NIH HHS
• R01 ES028277 NIEHS NIH HHS
• T32 ES007141 NIEHS NIH HHS
• R01 ES025214 NIEHS NIH HHS
• R01 ES020349 NIEHS NIH HHS

Collapse

Affiliation(s)

Jessie P Buckley Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Junyi Zhou Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
Katherine M Marquess Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
Bruce P Lanphear Faculty of Health Sciences, Simon Fraser University, Vancouver, Canada
Kim M Cecil Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Aimin Chen Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
Clara G Sears Christina Lee Brown Envirome Institute, Department of Medicine, Division of Environmental Medicine, University of Louisville, KY, USA
Yingying Xu Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Kimberly Yolton Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Heidi J Kalkwarf Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Joseph M Braun Department of Epidemiology, Brown University, Providence, USA
Jordan R Kuiper Department of Environmental and Occupational Health, The George Washington University Milken Institute School of Public Health, Washington, D.C., USA

Collapse

Collaborators Collapse

Systematic evidence mapping of potential correlates of exposure for per- and poly-fluoroalkyl substances (PFAS) based on measured occurrence in biomatrices and surveys of dietary consumption and product use

Per- and poly-fluoroalkyl substances (PFAS) are widely observed in environmental media and often are found in indoor environments as well as personal-care and consumer products. Humans may be exposed through water, food, indoor dust, air, and the use of PFAS-containing products. Information about relationships between PFAS exposure sources and pathways and the amounts found in human biomatrices can inform source-contribution assessments and provide targets for exposure reduction. This work collected and collated evidence for correlates of PFAS human exposure as measured through sampling of biomatrices and surveys of dietary consumption and use of consumer products and articles. A systematic evidence mapping approach was applied to perform a literature search, conduct title-abstract and full-text screening, and to extract primary data into a comprehensive database for 16 PFAS. Parameters of interest included: sampling dates and locations, cohort descriptors, PFAS measured in a human biomatrix, information about food consumption in 11 categories, use of products/articles in 11 categories, and reported correlation values (and their statistical strength). The literature search and screening process yielded 103 studies with information for correlates of PFAS exposures. Detailed data were extracted and compiled on measures of PFAS correlations between biomatrix concentrations and dietary consumption and other product/article use. A majority of studies (61/103; 59%) were published after 2015 with few (8/103; 8%) prior to 2010. Studies were most abundant for dietary correlates (n = 94) with fewer publications reporting correlate assessments for product use (n = 56), while some examined both. PFOA and PFOS were assessed in almost all studies, followed by PFHxS, PFNA, and PFDA which were included in >50% of the studies. No relevant studies included PFNS or PFPeS. Among the 94 studies of dietary correlates, significant correlations were reported in 83% of the studies for one or more PFAS. The significant dietary correlations most commonly were for seafood, meats/eggs, and cereals/grains/pulses. Among the 56 studies of product/article correlates, significant correlations were reported in 70% of the studies. The significant product/article correlations most commonly were for smoking/tobacco, cosmetics/toiletries, non-stick cookware, and carpet/flooring/furniture and housing. Six of 11 product/article categories included five or fewer studies, including food containers and stain- and water-resistant products. Significant dietary and product/article correlations most commonly were positive. Some studies found a mix of positive and negative correlations depending on the PFAS, specific correlate, and specific response level, particularly for fats/oils, dairy consumption, food containers, and cosmetics/toiletries. Most of the significant findings for cereals/grains/pulses were negative correlations. Substantial evidence was found for correlations between dietary intake and biomatrix levels for several PFAS in multiple food groups. Studies examining product/article use relationships were relatively sparse, except for smoking/tobacco, and would benefit from additional research. The resulting database can inform further assessments of dietary and product use exposure relationships and can inform new research to better understand PFAS source-to-exposure relationships. The search strategy should be extended and implemented to support living evidence review in this rapidly advancing area.

Associations of per- and polyfluoroalkyl substances with maternal metabolic and inflammatory biomarkers in early-to-mid-pregnancy

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) can disrupt metabolism. Early-to-mid pregnancy is characterized by amplified metabolic processes and inflammation to support maternal adaptations and fetal growth. Thus, we cross-sectionally evaluated whether PFAS are individually and jointly associated with these processes in early-to-mid pregnancy.

METHODS

Pregnant Illinois women (n = 452) provided fasted blood samples at median 17 weeks gestation. We quantified serum perfluorononanoic (PFNA), perfluorooctane sulfonic (PFOS), perfluorooctanoic (PFOA), methyl-perfluorooctane sulfonamide acetic acid (Me-PFOSA-AcOH), perfluorohexanesulfonic (PFHxS), perfluorodecanoic (PFDeA), and perfluoroundecanoic (PFUdA) acid. Key outcomes were plasma glucose, insulin, C-peptide, insulin-like growth factor 1 (IGF-1), adiponectin, leptin, triglycerides, free fatty acids, total cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein, tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6. We calculated homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL). We evaluated associations of PFAS with each metabolic/inflammatory biomarker individually using covariate-adjusted linear regression and jointly using quantile-based g-computation.

RESULTS

In linear regression, all PFAS (except Me-PFOSA-AcOH) were negatively associated with insulin, HOMA-IR, and leptin, whereas all PFAS were positively associated with HDL cholesterol. We also observed negative associations of some PFAS with TNF-α and MCP-1; positive associations with adiponectin and total cholesterol also emerged. Additionally, PFOS was positively, whereas Me-PFOSA-AcOH was negatively, associated with triglycerides and VLDL. Each 25% increase in the PFAS mixture was associated with -31.3% lower insulin (95%CI: -45.8, -12.9), -31.9% lower HOMA-IR (95%CI: -46.4, -13.4), and -9.4% lower leptin (95%CI: -17.3, -0.8), but 7.4% higher HDL cholesterol (95%CI: 4.6, 10.3). For most outcomes, the major contributors to the PFAS mixture often differed compared to single-PFAS analyses.

IMPLICATIONS

Individual and joint PFAS exposures were associated with markers of maternal metabolism and inflammation in pregnancy. Further investigation is needed to elucidate possible mechanisms and consequences of these findings.

Associations of dietary intake and longitudinal measures of per- and polyfluoroalkyl substances (PFAS) in predominantly Hispanic young Adults: A multicohort study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are pollutants linked to adverse health effects. Diet is an important source of PFAS exposure, yet it is unknown how diet impacts longitudinal PFAS levels.

OBJECTIVE

To determine if dietary intake and food sources were associated with changes in blood PFAS concentrations among Hispanic young adults at risk of metabolic diseases.

METHODS

Predominantly Hispanic young adults from the Children's Health Study who underwent two visits (CHS; n = 123) and young adults from NHANES 2013-2018 who underwent one visit (n = 604) were included. Dietary data at baseline was collected using two 24-hour dietary recalls to measure individual foods and where foods were prepared/consumed (home/restaurant/fast-food). PFAS were measured in blood at both visits in CHS and cross-sectionally in NHANES. In CHS, multiple linear regression assessed associations of baseline diet with longitudinal PFAS; in NHANES, linear regression was used.

RESULTS

In CHS, all PFAS except PFDA decreased across visits (all p < 0.05). In CHS, A 1-serving higher tea intake was associated with 24.8 %, 16.17 %, and 12.6 % higher PFHxS, PFHpS, and PFNA at follow-up, respectively (all p < 0.05). A 1-serving higher pork intake was associated with 13.4 % higher PFOA at follow-up (p < 0.05). Associations were similar in NHANES, including unsweetened tea, hot dogs, and processed meats. For food sources, in CHS each 200-gram increase in home-prepared food was associated with 0.90 % and 1.6 % lower PFOS at baseline and follow-up, respectively, and in NHANES was associated with 0.9 % lower PFDA (all p < 0.05).

CONCLUSION

Results suggest that beverage consumption habits and food preparation are associated with differences in PFAS levels in young adults. This highlights the importance of diet in determining PFAS exposure and the necessity of public monitoring of foods and beverages for PFAS contamination.

Per- and polyfluoroalkyl substances and cardiometabolic diseases: A review

Per- and polyfluoroalkyl substances (PFAS) are a group of persistent and widespread environmental pollutants that represent a high concern for human health. They have been shown to be associated with several important physiological processes such as lipid metabolism and the immune system. Consequently, PFAS are suspected to play a role in cardiometabolic disease development. However, the evidence regarding associations between PFAS and overt cardiovascular disease and type 2 diabetes remains limited and inconsistent. To address this, we conducted a review of the epidemiological evidence. A deeper understanding of potential underlying molecular mechanisms may help to explain inconsistencies in epidemiological findings. Thus, to gain more mechanistic insight, we also summarized evidence from omics and laboratory studies into an adverse outcome pathway framework. Our observations indicate the potential for associations of PFAS with multiple molecular pathways that could have opposite associations with disease risk, which could be further modified by mixture composition, lifestyle factors or genetic polymorphisms. This identifies the need for exposome studies considering mixture effects, the use of multi-omics data to gain insight in relevant pathways and the integration of epidemiological and laboratory studies to enhance mechanistic understanding and causal inference. Improved comprehension is essential for environmental health risk assessments.

Interaction between the oxidative balance score and serum per- and poly-fluoroalkyl substances (PFASs) on liver health: analysis of the NHANES 2007-2018 dataset

BACKGROUND

Per- and poly-fluoroalkyl substances (PFASs) are pervasive synthetic compounds, prompting investigations into their intricate interactions with lifestyle factors and health indicators because of their enduring environmental presence and bioaccumulation. This study aimed to explore the effects of the oxidative balance score (OBS) and PFAS on liver-related indices.

METHODS

Twenty dietary and lifestyle factors were used to calculate the OBS. The serum concentrations of PFASs were measured, and their sum was calculated for analysis. The levels of liver markers were also evaluated. Linear regression models and interaction analyses were used to assess the associations between OBS, PFAS concentrations, and liver indices.

RESULTS

The results revealed an inverse association between high OBS and perfluorooctane sulfonic acid concentration, as well as the sum of PFAS concentrations. OBS was positively associated with liver markers. The PFAS concentrations were positively associated with total bilirubin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels. Interaction analyses revealed significant interactions between OBS and specific PFASs for alkaline phosphatase (interaction P < 0.05). Possible interactions were also found between OBS and specific PFASs for ALT, and AST levels (interaction P < 0.10).

CONCLUSIONS

This study clarified the association between total PFAS and OBS. This association was significant mainly for diet-related OBS. PFAS and OBS are associated with liver-related indicators in the blood.

Cardiometabolic health and per and polyfluoroalkyl substances in an Inuit population

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The role of perfluorooctane sulfonic acid (PFOS) exposure in inflammation of intestinal tissues and intestinal carcinogenesis

PFAS (per- and polyfluoroalkyl substances) are organofluorine substances that are used commercially in products like non-stick cookware, food packaging, personal care products, fire-fighting foam, etc. These chemicals have several different subtypes made of varying numbers of carbon and fluorine atoms. PFAS substances that have longer carbon chains, such as PFOS (perfluorooctane sulfonic acid), can potentially pose a significant public health risk due to their ability to bioaccumulate and persist for long periods of time in the body and the environment. The National Academies Report suggests there is some evidence of PFOS exposure and gastrointestinal (GI) inflammation contributing to ulcerative colitis. Inflammatory bowel diseases such as ulcerative colitis are precursors to colorectal cancer. However, evidence about the association between PFOS and colorectal cancer is limited and has shown contradictory findings. This review provides an overview of population and preclinical studies on PFOS exposure and GI inflammation, metabolism, immune responses, and carcinogenesis. It also highlights some mitigation approaches to reduce the harmful effects of PFOS on GI tract and discusses the dietary strategies, such as an increase in soluble fiber intake, to reduce PFOS-induced alterations in cellular lipid metabolism. More importantly, this review demonstrates the urgent need to better understand the relationship between PFOS and GI pathology and carcinogenesis, which will enable development of better approaches for interventions in populations exposed to high levels of PFAS, and in particular to PFOS.

Dietary per- and polyfluoroalkyl substance (PFAS) exposure in adolescents: The HOME study

BACKGROUND

Diet is the primary exposure pathway for per- and polyfluoroalkyl substances (PFAS) in non-occupationally exposed populations. Few studies have examined associations of dietary quality and macronutrient intake with PFAS exposure among US adolescents.

OBJECTIVE

To assess relationships of self-reported dietary quality and macronutrient intake with serum PFAS concentrations in adolescents.

METHODS

We used cross-sectional data from 193 Cincinnati, Ohio area adolescents (median age 12.3 years) collected from 2016 to 2019. Using 24-h food recalls completed by adolescents on three separate days, we derived Healthy Eating Index (HEI) scores, HEI components, and macronutrient intake. We measured perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) concentrations in fasting serum samples. Using linear regression, we estimated covariate-adjusted associations between dietary variables and serum PFAS concentrations.

RESULTS

The median HEI score was 44 and median serum PFOA, PFOS, PFHxS, and PFNA concentrations were 1.3, 2.4, 0.7, and 0.3 ng/mL respectively. In adjusted models, higher total HEI scores, whole fruit and total fruit HEI component scores, and total dietary fiber intake were associated with lower concentrations of all four PFAS. For example, serum PFOA concentrations were 7% lower (95% CI: -15, 2) per standard deviation increase in total HEI score and 9% lower (95% CI: -18, 1) per standard deviation increase in dietary fiber.

SIGNIFICANCE

Given adverse health effects associated with PFAS exposure, it is crucial to understand modifiable exposure pathways. Findings from this study may inform future policy decisions aiming to limit human exposure to PFAS.

Folate concentrations and serum perfluoroalkyl and polyfluoroalkyl substance concentrations in adolescents and adults in the USA (National Health and Nutrition Examination Study 2003-16): an observational study

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a family of highly fluorinated aliphatic compounds, which are widely used in commercial applications, including food packaging, textiles, and non-stick cookware. Folate might counteract the effects of environmental chemical exposures. We aimed to explore the relationship between blood folate biomarker concentrations and PFAS concentrations.

METHODS

This observational study pooled cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2003 to 2016 cycles. NHANES is a population-based national survey that measures the health and nutritional status of the US general population every 2 years by means of questionnaires, physical examination, and biospecimen collection. Folate concentrations in red blood cells and in serum, and perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS) concentrations in serum were examined. We used multivariable regression models to assess the percentage change in serum PFAS concentrations in relation to changes in folate biomarker concentrations. We additionally used models with restricted cubic splines to investigate the shape of these associations.

FINDINGS

This study included 2802 adolescents and 9159 adults who had complete data on PFAS concentrations, folate biomarkers, and covariates, were not pregnant, and had never had a cancer diagnosis at the time of the survey. The mean age was 15·4 years (SD 2·3) for adolescents and 45·5 years (17·5) for adults. The proportion of male participants was slightly higher in adolescents (1508 [54%] of 2802 participants) than in adults (3940 [49%] of 9159 participants). We found negative associations between red blood cell folate concentrations and serum concentrations of PFOS (percentage change for a 2·7 fold-increase in folate level -24·36%, 95% CI -33·21 to -14·34) and PFNA (-13·00%, -21·87 to -3·12) in adolescents, and PFOA (-12·45%, -17·28 to -7·35), PFOS (-25·30%, -29·67 to -20·65), PFNA (-21·65%, -26·19 to -16·82), and PFHxS (-11·70%, -17·32 to 5·70) in adults. Associations for serum folate concentrations and PFAS were in line with those found for red blood cell folate levels, although the magnitude of the effects was lower. Restricted cubic spline models suggested linearity of the observed associations, particularly for associations in adults.

INTERPRETATION

In this large-scale, nationally representative study, we found consistent inverse associations for most examined serum PFAS compounds in relation to folate concentrations measured in either red blood cells or serum among both adolescents and adults. These findings are supported by mechanistic in-vitro studies that show the potential of PFAS to compete with folate for several transporters implicated in PFAS toxicokinetics. If confirmed in experimental settings, these findings could have important implications for interventions to reduce the accumulated PFAS body burden and mitigate the related adverse health effects.

FUNDING

United States National Institute of Environmental Health Sciences.

Associations of dietary fiber intake with chronic inflammatory airway diseases and mortality in adults: a population-based study

Objective

The objective of this study was to investigate the potential association between dietary fiber intakes and the prevalence of chronic inflammatory airway diseases (CIAD), as well as mortality in participants with CIAD.

Methods

Data was collected from the National Health and Nutrition Examination Survey (NHANES) 2013-2018, with dietary fiber intakes being calculated as the average of two 24-h dietary reviews and divided into four groups. CIAD included self-reported asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). Through December 31, 2019, mortality was identified from the National Death Index. In cross-sectional studies, multiple logistic regressions were used to assess dietary fiber intakes associated with the prevalence of total and specific CIAD. Dose-response relationships were tested using restricted cubic spline regression. In prospective cohort studies, cumulative survival rates were calculated using the Kaplan-Meier method and compared using log-rank tests. Multiple COX regressions were used to assess dietary fiber intakes associated with mortality in participants with CIAD.

Results

A total of 12,276 adults were included in this analysis. The participants had a mean age of 50.70 ± 17.4 years and was 47.2% male. The prevalence of CIAD, asthma, chronic bronchitis, and COPD were 20.1, 15.2, 6.3, and 4.2%, respectively. The median daily consumption of dietary fiber was 15.1 [IQR 10.5, 21.1] g. After adjusting for all confounding factors, linear and negative associations were observed between dietary fiber intakes and the prevalence of total CIAD (OR = 0.68 [0.58-0.80]), asthma (OR = 0.71 [0.60-0.85]), chronic bronchitis (OR = 0.57 [0.43-0.74]) and COPD (OR = 0.51 [0.34-0.74]). In addition, the fourth quartile of dietary fiber intake levels remained significantly associated with a decreased risk of all-cause mortality (HR = 0.47 [0.26-0.83]) compared to the first quartile.

Conclusion

Dietary fiber intakes were found to be correlated with the prevalence of CIAD, and higher dietary fiber intakes were associated with a reduced mortality in participants with CIAD.

Inverse relationship between dietary fiber intake and environmental exposure to acrylamide

Dietary fiber intake was thought to decrease some environmental pollutant exposure by increasing gastrointestinal excretion. While diet is considered the major source of exposure to acrylamide (AA), the impact of dietary fiber intake on acrylamide (AA) exposure is still unknown. We analyzed the associations between dietary fiber intake and AA hemoglobin biomarkers [hemoglobin adducts of acrylamide (HbAA) and glycinamide (HbGA), and sum of HbAA and HbGA (HbAA + HbGA)] among 3448 US adults who participated in the National Health and Nutrition Examination Survey (NHANES) 2013-2016. Multivariable linear regression and cubic spline models were conducted to estimate the associations between dietary fiber intake and AA hemoglobin biomarkers. Dietary fiber intake had a strong inverse and J-shaped association with AA hemoglobin biomarkers. In the fully adjusted linear regression model, compared with participants in the lowest dietary fiber quantile, the adjusted percent change with 95% confidence intervals (CIs) in HbAA for the highest dietary fiber quantile was - 19.7% (- 26.7%, - 13.1%); for HbGA, it was - 12.2% (- 18.9%, - 4.9%), and for HbAA + HbGA, it was - 17.3% (- 23.7%, - 10.4%). Associations between higher dietary fiber intake and lower levels of environmental exposure to acrylamide hemoglobin biomarkers suggest the need to increase dietary fiber intake.

Effect of lifestyle-based lipid lowering interventions on the relationship between circulating levels of per-and polyfluoroalkyl substances and serum cholesterol

Exposure to certain per-and polyfluoroalkyl substances (PFAS) has been shown to be positively associated with total and/or low-density lipoprotein cholesterol. Examining this association in lipid lowering interventions may provide additional evidence linking PFAS to cardiovascular risk. We examined the relationship of 6 PFAS with cholesterol in a 6-month lifestyle-based intervention. We quantitated PFAS in 350 individuals at baseline and post intervention and examined associations of PFAS with cholesterol before and after intervention. Food frequency questionnaires and GIS analyses were used to investigate PFAS hotspots and possible exposure routes. Cholesterol significantly decreased following intervention and in parallel, PFOS, PFOA, PFHxS, and PFHpA significantly decreased. PFOS was positively correlated with total cholesterol only post-intervention. We observed that PFOS was distributed among both non-albumin and albumin lipoprotein fractions pre-intervention, but entirely in albumin fraction post-intervention. Our results indicate that lipid-lowering via lifestyle modification may impact on circulating levels or distribution of PFAS.

Perfluoroalkyl Substance Serum Concentrations and Cholesterol Absorption-Inhibiting Medication Ezetimibe

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are human-made compounds with a widespread presence in human blood and other organs. PFAS have been associated with multiple health effects, including higher serum cholesterol and LDL cholesterol.

OBJECTIVE

Potential population differences in serum PFAS attributable to ezetimibe, a medication that inhibits cholesterol absorption, are of interest for several reasons. The "C8" Health Project survey data from six contaminated water districts in the mid-Ohio Valley of the United States provide a wide enough range of serum PFAS and a sufficient number of ezetimibe takers to explore this topic.

METHODS

A total of 44,126 adult participants of the C8 Health Survey were included in the community-based study. The status of taking (1075) or non-taking of ezetimibe, alone or in combination with another lipid-lowering agent, was acquired. The geometric mean serum concentrations of the four most commonly detected serum PFAS were compared based on the status of ezetimibe use.

RESULTS

There is no significant difference in serum concentrations of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorononanoic acid (PFNA) between ezetimibe users and non-users after adjustment for age, sex, body mass index, estimated glomerular filtration rate (eGFR), cigarette smoking, education, and average household income.

CONCLUSION

The sterol absorption-inhibiting medication ezetimibe does not appear to affect serum PFAS concentrations. We sought but did not find direct evidence that ezetimibe could inhibit PFAS uptake nor inferential evidence that inter-individual differences in sterol absorption could provide a confounding factor explanation for the association of serum total- and LDL-cholesterol with serum PFAS.

Molecular and genetic analyses revealed the phytotoxicity of perfluorobutane sulfonate

Perfluorobutane sulfonate (PFBS) has oily and hydrophobic characteristics similar to those of perfluorooctane sulfonic acid (PFOS), which is an environmental organic pollutant and has gradually become the main substitute for PFOS in industry. Several studies have revealed the potential toxicity of PFBS in animals. PFBS can be taken up and accumulate in plants; however, whether and how PFBS affects plant growth remain largely unclear. A low concentration of PFBS did not affect plant growth, indicating that it had higher environmental safety than other perfluorinated compounds; however, a high concentration of PFBS (>1 mM) markedly inhibited primary root growth in Arabidopsis thaliana. Subsequently, we investigated the molecular mechanisms underlying plant growth mediated by high concentrations of PFBS. First, a genome-wide transcriptomic analysis revealed that PFBS altered the expression of genes associated with phytohormone signaling pathways. Combining physio-biochemical and genetic analyses, we next demonstrated that PFBS reduced the contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and disrupted the two signaling pathways in plants, finally inhibiting root growth. Moreover, a high concentration of PFBS also inhibited photosynthesis by comprehensively repressing the expression of genes related to the Calvin cycle and the photosynthetic apparatus. Such an understanding is helpful for elucidating the phytotoxicity of PFBS and provides a new strategy for toxicology research on organic pollutants in plants.

Is the cholesterol-perfluoroalkyl substance association confounded by dietary fiber intake?: a Bayesian analysis of NHANES data with adjustment for measurement error in fiber intake

BACKGROUND

Serum concentrations of total cholesterol and related lipid measures have been associated with serum concentrations of per- and polyfluoroalkyl substances (PFAS) in humans, even among those with only background-level exposure to PFAS. Fiber is known to decrease serum cholesterol and a recent report based on National Health and Nutrition Examination Survey (NHANES) showed that PFAS and fiber are inversely associated. We hypothesized that confounding by dietary fiber may account for some of the association between cholesterol and PFAS.

METHODS

We implemented a Bayesian correction for measurement error in estimated intake of dietary fiber to evaluate whether fiber confounds the cholesterol-PFAS association. The NHANES measure of diet, two 24-h recalls, allowed calculation of an estimate of the "true" long-term fiber intake for each subject. We fit models to the NHANES data on serum cholesterol and serum concentration of perfluorooctanoic acid (PFOA) and two other PFAS for 7,242 participants in NHANES.

RESULTS

The Bayesian model, after adjustment for soluble fiber intake, suggested a decrease in the size of the coefficient for PFOA by 6.4% compared with the fiber-unadjusted model.

CONCLUSIONS

The results indicated that the association of serum cholesterol with PFAS was not substantially confounded by fiber intake.

Metabolomic, Lipidomic, Transcriptomic, and Metagenomic Analyses in Mice Exposed to PFOS and Fed Soluble and Insoluble Dietary Fibers

BACKGROUND

Perfluorooctane sulfonate (PFOS) is a persistent environmental pollutant that has become a significant concern around the world. Exposure to PFOS may alter gut microbiota and liver metabolic homeostasis in mammals, thereby increasing the risk of cardiometabolic diseases. Diets high in soluble fibers can ameliorate metabolic disease risks.

OBJECTIVES

We aimed to test the hypothesis that soluble fibers (inulin or pectin) could modulate the adverse metabolic effects of PFOS by affecting microbe-liver metabolism and interactions.

METHODS

Male C57BL/6J mice were fed an isocaloric diet containing different fibers: a) inulin (soluble), b) pectin (soluble), or c) cellulose (control, insoluble). The mice were exposed to PFOS in drinking water (3 μ g / g  per day ) for 7 wk. Multi-omics was used to analyze mouse liver and cecum contents.

RESULTS

In PFOS-exposed mice, the number of differentially expressed genes associated with atherogenesis and hepatic hyperlipidemia were lower in those that were fed soluble fiber than those fed insoluble fiber. Shotgun metagenomics showed that inulin and pectin protected against differences in microbiome community in PFOS-exposed vs. control mice. It was found that the plasma PFOS levels were lower in inulin-fed mice, and there was a trend of lower liver accumulation of PFOS in soluble fiber-fed mice compared with the control group. Soluble fiber intake ameliorated the effects of PFOS on host hepatic metabolism gene expression and cecal content microbiome structure.

DISCUSSIONS

Results from metabolomic, lipidomic, and transcriptomic studies suggest that inulin- and pectin-fed mice were less susceptible to PFOS-induced liver metabolic disturbance, hepatic lipid accumulation, and transcriptional changes compared with control diet-fed mice. Our study advances the understanding of interaction between microbes and host under the influences of environmental pollutants and nutrients. The results provide new insights into the microbe-liver metabolic network and the protection against environmental pollutant-induced metabolic diseases by high-fiber diets. https://doi.org/10.1289/EHP11360.

Antibody response to COVID-19 vaccines among workers with a wide range of exposure to per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are a broad class of synthetic chemicals; some are present in most humans in developed countries. Several studies have shown associations between certain PFAS, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), and reduced antibody concentration after vaccination against diseases such as Tetanus. Recent studies have reported associations between COVID-19 occurrence and exposure to certain types of PFAS. However, studies of antibody concentration after COVID-19 vaccination in relation to PFAS serum concentrations have not been reported. We examined COVID-19 antibody responses to vaccines and PFAS serum concentrations among employees and retirees from two 3M facilities, one of which historically manufactured PFOS, PFOA, and perfluorohexane sulfonic acid (PFHxS). Participants completed enrollment and follow-up study visits in the Spring of 2021, when vaccines were widely available. In total 415 participants with 757 observations were included in repeated measures analyses. Log-transformed concentrations of anti-spike IgG and neutralizing antibodies were modeled in relation to concentration of PFAS at enrollment after adjusting for antigenic stimulus group (9 groups determined by COVID-19 history and number and type of vaccination) and other variables. The fully adjusted IgG concentration was 3.45 percent lower (95% CI -7.03, 0.26) per 14.5 ng/mL (interquartile range) increase in PFOS; results for neutralizing antibody and PFOS were similar. For PFOA, PFHxS, and perfluorononanoic acid (PFNA), the results were comparable to those for PFOS, though of smaller magnitude. In our study data, the fully adjusted coefficients relating concentration of vaccine-induced antibodies to COVID-19 and interquartile range difference in serum concentration of PFOS, PFOA, PFHxS, and PFNA were inverse but small with confidence intervals that included zero. Our analysis showed that the coefficient for the four PFAS examined in detail was considerably affected by adjustment for antigenic stimulus group.

Retracted: Exposure to Per- and Polyfluoroalkyl Substances and Mortality in U.S. Adults: A Population-Based Cohort Study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants associated with diseases such as cancer and dyslipidemia. However, few studies have investigated the association between PFAS mixture exposure and mortality in general populations.

OBJECTIVES

This study aimed to explore the association between PFAS mixture, perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) and mortality in U.S. adults by a nationally representative cohort.

METHODS

Adults ≥ 18  years of age who were enrolled in the National Health and Nutrition Examination Survey (NHANES) (1999-2014) were included in our study. Baseline serum concentrations of seven PFAS were measured and individuals were followed up to 31 December 2015. Hazard ratios (HRs) and confidence intervals (CIs) were estimated using Cox proportional hazards models. Association between PFAS mixture exposure and mortality was analyzed using the k-means method by clustering PFAS mixtures into subgroups. Association between PFOA/PFOS exposure and mortality was subsequently analyzed in both continuous and categorical models.

RESULTS

During the follow-up period, 1,251 participants died. In the mixture analysis, the k-means algorithm clustered participants into low-, medium-, and high-exposure groups. Compared with the low-exposure group, participants in the high-exposure group showed significantly higher risks for all-cause mortality (HR = 1.38 ; 95% CI: 1.07, 1.80), heart disease mortality (HR = 1.58 ; 95% CI: 1.05, 2.51), and cancer mortality (HR = 1.70 ; 95% CI: 1.08, 2.84). In single PFAS analysis, PFOS was found to be positively associated with all-cause mortality (third vs. first tertile HR = 1.57 ; 95% CI: 1.22, 2.07), heart disease mortality (third vs. first tertile HR = 1.65 ; 95% CI: 1.09, 2.57), and cancer mortality (third vs. first tertile HR = 1.75 ; 95% CI: 1.10, 2.83), whereas PFOA exposure had no significant association with mortality. Assuming the observed association is causal, the number of deaths associated with PFOS exposure (≥ 17.1 vs. < 7.9  ng / mL ) was ∼ 382,000 (95% CI: 176,000, 588,000) annually between 1999 and 2015, and it decreased to 69,000 (95% CI: 28,000, 119,000) annually between 2015 and 2018. The association between PFOS and mortality was stronger among women and people without diabetes.

DISCUSSION

We observed a positive association between PFAS mixture exposure and mortality among U.S. adults. Limitations of this study include the potential for unmeasured confounding, selection bias, a relatively small number of deaths, and only measuring PFAS at one point in time. Further studies with serial measures of PFAS concentrations and longer follow-ups are necessary to elucidate the association between PFAS and mortality from specific causes. https://doi.org/10.1289/EHP10393.

Biological Utility of Fluorinated Compounds: from Materials Design to Molecular Imaging, Therapeutics and Environmental Remediation

The applications of fluorinated molecules in bioengineering and nanotechnology are expanding rapidly with the controlled introduction of fluorine being broadly studied due to the unique properties of C-F bonds. This review will focus on the design and utility of C-F containing materials in imaging, therapeutics, and environmental applications with a central theme being the importance of controlling fluorine-fluorine interactions and understanding how such interactions impact biological behavior. Low natural abundance of fluorine is shown to provide sensitivity and background advantages for imaging and detection of a variety of diseases with ¹⁹F magnetic resonance imaging, ¹⁸F positron emission tomography and ultrasound discussed as illustrative examples. The presence of C-F bonds can also be used to tailor membrane permeability and pharmacokinetic properties of drugs and delivery agents for enhanced cell uptake and therapeutics. A key message of this review is that while the promise of C-F containing materials is significant, a subset of highly fluorinated compounds such as per- and polyfluoroalkyl substances (PFAS), have been identified as posing a potential risk to human health. The unique properties of the C-F bond and the significant potential for fluorine-fluorine interactions in PFAS structures necessitate the development of new strategies for facile and efficient environmental removal and remediation. Recent progress in the development of fluorine-containing compounds as molecular imaging and therapeutic agents will be reviewed and their design features contrasted with environmental and health risks for PFAS systems. Finally, present challenges and future directions in the exploitation of the biological aspects of fluorinated systems will be described.

Exposure routes, bioaccumulation and toxic effects of per- and polyfluoroalkyl substances (PFASs) on plants: A critical review

Per- and polyfluoroalkyl substances (PFASs) are artificial persistent organic pollutants ubiquitous in ecosystem, and their bioaccumulation and adverse outcomes in plants have attracted extensive concerns. Here, we review the toxic effects of PFASs encountered by various plants from physiological, biochemical and molecular perspectives. The exposure routes and bioaccumulation of PFASs in plants from contaminated sites are also summarized. The bioaccumulation of PFASs in plants from contaminated sites varied between ng/g and μg/g levels. The 50% inhibition concentration of PFASs for plant growth is often several orders of magnitude higher than the environmentally relevant concentrations (ERCs). ERCs of PFASs rarely lead to obvious phenotypic/physiological damages in plants, but markedly perturb some biological activities at biochemical and molecular scales. PFAS exposure induces the over-generated reactive oxygen species and further damages plant cell structure and organelle functions. A number of biochemical activities in plant cells are perturbed, such as photosynthesis, gene expression, protein synthesis, carbon and nitrogen metabolisms. To restore the desire states of cells exposed to PFASs, plants initiate several detoxifying mechanisms, including enzymatic antioxidants, non-enzymatic antioxidants, metallothionein genes and metabolic reprogramming. Future challenges and opportunities in PFAS phytotoxicity studies are also proposed in the review.

Legacy and emerging per- and polyfluoroalkyl substances (PFAS) in the Bohai Sea and its inflow rivers

In this study, the occurrence, distribution, sources, and risk of 29 legacy and emerging per- and polyfluoroalkyl substances (PFAS) in four kinds of environmental matrices in the Bohai Sea were investigated. The ∑PFAS concentrations were in the range of 0.40 ~ 61.4 ng/g dry weight (dw) in inflow river sediments, 0.48 ~ 61.4 ng/g dw in soil near river inflow, 0.37 ~ 4.18 ng/g dw in sea sediments, and 13.3 ~ 718 ng/L in seawater. PFAS with eight carbons accounted for > 62.2% by mass, in all samples. Perfluorooctanoic acid (PFOA) was the dominant PFAS both by mass and occurrence. Seawater from Laizhou Bay (south of the Bohai Sea) and sediments of Liaodong Bay (northeast of the Bohai Sea) had the highest levels of ∑PFAS. The sediment-water partition coefficient and organic carbon content normalized partition coefficient (log K_d and log K_oc) were calculated using measured PFAS concentrations to determine their distribution in seawater and sea sediments. The values of log K_d and log K_oc values increased with the increasing CF₂ units for perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs). Six primary sources were identified in this region, including aqueous film-forming foams (AFFF), metal plating, food packages, fluorine chemical industry, fluoropolymer manufacture, and domestic pollution. The risk quotient (RQ) values of PFAS were all < 1, indicating that organisms of the Bohai Sea were at low risk of PFAS exposure.

Why is elevation of serum cholesterol associated with exposure to perfluoroalkyl substances (PFAS) in humans? A workshop report on potential mechanisms

Serum concentrations of cholesterol are positively correlated with exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in humans. The associated change in cholesterol is small across a broad range of exposure to PFOA and PFOS. Animal studies generally have not indicated a mechanism that would account for the association in humans. The extent to which the relationship is causal is an open question. Nonetheless, the association is of particular importance because increased serum cholesterol has been considered as an endpoint to derive a point of departure in at least one recent risk assessment. To gain insight into potential mechanisms for the association, both causal and non-causal, an expert workshop was held Oct 31 and Nov 1, 2019 to discuss relevant data and propose new studies. In this report, we summarize the relevant background data, the discussion among the attendees, and their recommendations for further research.

Dietary patterns and PFAS plasma concentrations in childhood: Project Viva, USA

BACKGROUND

Diet is thought to account for most adult human exposure to per- and polyfluoroalkyl substances (PFAS). Children are particularly vulnerable to adverse health effects of PFAS and may have different eating habits than adults. However, studies of dietary patterns and PFAS in children are limited.

METHODS

We studied 548 Boston-area children with food frequency questionnaire data (89 food items) in early childhood (median age 3.3 years) and plasma concentrations of 6 PFAS quantified in mid-childhood (median age 7.7 years). We used univariate linear regression to examine associations between each food item and PFAS, accounting for multiple comparisons. We next used reduced rank regression (RRR) to estimate overall percent variation in PFAS explained by diet and identify dietary patterns most correlated with PFAS. All models were adjusted for race/ethnicity, maternal education, and household income.

RESULTS

In univariate analyses, 2-(N-methyl-perfluorooctane sulfonamide) acetate (MeFOSAA) plasma concentrations were 17.8% (95% CI: 7.2, 29.5) and 17.0% (95% CI: 6.4, 28.7) higher per SD increment in intake of ice cream and soda, respectively. RRR identified 6 dietary patterns that together explained 18% variation in the plasma concentrations of the 6 PFAS, of which 50% was explained by a dietary pattern consisting of primarily packaged foods (including ice cream and soda) and fish. Children with higher intake of the packaged foods and fish dietary pattern had higher plasma concentrations of all PFAS, particularly MeFOSAA and PFOS.

CONCLUSIONS

Our analysis examined food intake in association with several PFAS in children and identified dietary determinants that may be sources of PFAS exposure or reflect correlated lifestyle or toxicokinetic factors. Further investigation may help inform measures to modify childhood PFAS exposure.

Serum Concentration of Antibodies to Mumps, but Not Measles, Rubella, or Varicella, Is Associated with Intake of Dietary Fiber in the NHANES, 1999-2004

Treatment with prebiotics, a type of dietary fiber, was recently shown to increase antibody concentrations following influenza vaccination in a meta-analysis of clinical trials. In observational epidemiologic studies it is not possible to estimate intake of prebiotics, but quantifying intake of dietary fiber is routine. Our objective was to investigate the potential effect of dietary fiber on immunogenicity. We examined serum antibody concentrations (Measles, Mumps, Rubella, and Varicella) in relation to dietary fiber in more than 12,000 subjects in the U.S. National Health and Nutrition Examination Survey (NHANES) for the period 1999-2004. Data from one (1999-2002) or two (2003-2004) dietary recalls were used to calculate fiber intake. For Mumps the adjusted percentage difference in antibody concentration per interquartile range intake in energy-adjusted dietary fiber was 6.34% (95% confidence interval, 3.10, 9.68). Fiber from grain-based foods was more positively associated than fiber from other fiber-containing food groups. The association was slightly larger among subgroups with higher fiber intake, greater interquartile range in fiber intake, and less measurement error. Furthermore, based on the reliability of the diet recalls in 2003-2004, we calculated that the percentage difference per interquartile increment was substantially attenuated by measurement error. Dietary fiber may have a favorable influence on the immunogenicity of some vaccines or natural infections.