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

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.

Association between PFAS exposure and metabolic-related biomarkers in Spanish adolescents

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) exert endocrine disruptive effects on the endocrine-metabolic axis. Emerging knowledge suggests that kisspeptin may play a key role in these effects.

OBJECTIVE

To assess the cross-sectional association of blood PFAS concentrations with kisspeptin levels, KISS1 gene DNA methylation, and metabolic-related biomarkers in adolescent males from the Spanish INMA-Granada cohort.

METHODS

Seven PFAS and twelve biomarkers (glucose-GLU, total cholesterol-TC, triglycerides, LDL, HDL, ALP, AST, ALT, GGT, total bilirubin-BILT, direct bilirubin-BILD, and urea) were measured in plasma and serum, respectively, from 129 adolescent males (15-17 yrs). Systolic and diastolic blood pressure (SBP, DBP), pulse, z-scored body mass index, kisspeptin protein levels (n = 104) and whole blood KISS1 DNA methylation (n = 117) were determined. Linear regression models, weighted quantile sum (WQS), and Bayesian kernel machine (BKMR) were fit.

RESULTS

PFHpA was associated with lower GLU levels [% change per log-unit increase in plasma concentrations (95%CI) = -4.73 (-8.98;-0.28)], and PFUnDA with higher GLU, TC, and HDL levels. In models adjusted by kisspeptin level, PFOS was associated with higher SBP [3.42 (-0.12; 7.09)]. Additionally, PFNA and total PFAS concentrations were associated with higher kisspeptin levels [3.91 (0.55; 7.37) and 6.14 (0.47; 12.13), respectively]. Mixture models showed that combined PFAS exposure was associated with higher HDL, lower hepatic biomarkers (ALT, BILD) and higher kisspeptin levels.

CONCLUSION

Certain PFAS (e.g. PFUnDA) and their mixture were associated with metabolic-related biomarkers, mainly GLU, HDL, and SBP. These associations may be influenced by kisspeptin levels. More studies are needed to verify these observations.

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.

Environment-wide association study of five per- and polyfluoroalkyl substance (PFASs) exposure pathways in Korean adolescents from the Korean National Environmental Health Survey (2018-2020)

Per- and polyfluoroalkyl substances (PFASs) are widely used in consumer products and are easily encountered in daily life. PFASs that accumulate in the human body can negatively affect adolescent health. This study aimed to identify key exposure pathways that influence serum PFAS levels in Korean adolescents, using data from the Korean National Environmental Health Survey (2018-2020) cycle 4. By employing an environment-wide association study, we assessed residential, lifestyle, and dietary factors associated with serum PFAS levels. Serum levels of five PFAS compounds-perfluorooctanoic acid, perfluorooctane sulfonate, perfluorohexane sulfonate, perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA)-were measured in 825 adolescents. Multivariable linear regressions were performed to explore the association between serum PFAS levels and 102 potential exposure-pathway variables. The Benjamini-Hochberg procedure was then applied to calculate false discovery rate-adjusted p-values, with values < 0.01 considered statistically significant. For internal validation, least absolute shrinkage and selection operator regression was conducted 3000 times. We found that frequent fish consumption (>once a week) was strongly associated with increased serum levels of PFNA and PFDA. Frequent consumption of shellfish (>once a month), crustaceans (>once a week), and vegetables (≥once a day) was associated with increased serum levels of PFDA. Living near roads with self-reported high traffic volume was linked to higher PFDA concentrations. Further research is necessary to assess additional exposure pathways and to develop effective strategies to minimize PFAS exposure during adolescence.

Examining disparities in PFAS plasma concentrations: Impact of drinking water contamination, food access, proximity to industrial facilities and superfund sites

BACKGROUND

Most of the US population is exposed to per- and polyfluorinated substances (PFAS) through various environmental media and these sources of PFAS exposure coupled with disproportionate co-localization of PFAS-polluting facilities in under-resourced communities may exacerbate disparities in PFAS-associated health risks.

METHOD

We leveraged two cohorts in Southern California with 8 PFAS concentrations measured in plasma. We obtained PFAS water testing data from the Third Unregulated Contaminant Monitoring Rule and state monitoring data, census tract-level information on food access using the Food Access Research Atlas, the location of Superfund sites on the National Priorities List, and data on facilities known to release PFAS pollutants. These data were then spatially linked to the participants' home addresses.

RESULTS

In the first cohort, we found that detections of PFOS, PFOA, and PFHxS in drinking water were associated with 1.54 ng/mL (95% CI: 0.77, 2.32), 0.47 ng/mL (0.25, 0.68), and 1.16 ng/mL (0.62, 1.71) increase in plasma PFOS, PFOA, and PFHxS. The presence of Superfund sites was associated with higher plasma concentrations of PFOS, PFHxS, PFPeS, and PFHpS (betas [95% CIs]: 0.96 [0.21, 1.71], 0.9 [0.22, 1.58], 0.04 [0.02, 0.06] and 0.05 [0.02, 0.09], respectively). Each additional PFAS-polluting facility present in the neighborhood was associated with a 0.9 ng/mL (0.03, 0.15) increase in the concentration of PFOS. In the other cohort, we found that the presence of Superfund sites was associated with higher plasma PFDA, PFHpS, PFOS (betas [95% CIs]: 0.03 [0.01, 0.06], 0.05 [0.01, 0.09], and 1.96 [0.31, 3.62]). Neighborhood low access to food was associated with a 2.51 ng/mL (0.7, 4.31) increase in plasma PFOS, 0.6 ng/mL (0.16, 1.06) increase in plasma PFOA and 0.06 (0.02, 0.1) increase in plasma PFHpS.

CONCLUSION

Reducing sources of PFAS exposure in under-resourced neighborhoods may help reduce disparities in human exposure levels.

Exposure to per- and polyfluoroalkyl substances (PFAS) in North Carolina homes: results from the indoor PFAS assessment (IPA) campaign

Per and polyfluoroalkyl substances (PFAS) are ubiquitous in the indoor environment, resulting in indoor exposure. However, a dearth of concurrent indoor multi-compartment PFAS measurements, including air, has limited our understanding of the contributions of each exposure pathway to residential PFAS exposure. As part of the Indoor PFAS Assessment (IPA) Campaign, we measured 35 neutral and ionic PFAS in air, settled dust, drinking water, clothing, and on surfaces in 11 North Carolina homes. Ionic and neutral PFAS measurements reported previously and ionic PFAS measurements reported herein for drinking water (1.4-34.1 ng L-1), dust (202-1036 ng g-1), and surfaces (4.1 × 10-4-1.7 × 10-2 ng cm-2) were used to conduct a residential indoor PFAS exposure assessment. We considered inhalation of air, ingestion of drinking water and dust, mouthing of clothing (children only), and transdermal uptake from contact with dust, air, and surfaces. Average intake rates were estimated to be 3.6 ng kg-1 per day (adults) and 12.4 ng kg-1 per day (2 year-old), with neutral PFAS contributing over 80% total PFAS intake. Excluding dietary ingestion, which was not measured, inhalation contributed over 65% of PFAS intake and was dominated by neutral PFAS because fluorotelomer alcohol (FTOH) concentrations in air were several orders of magnitude greater than ionic PFAS concentrations. Perfluorooctanoic acid (PFOA) intake was 6.1 × 10-2 ng kg-1 per day (adults) and 1.5 × 10-1 ng kg-1 per day (2 year-old), and biotransformation of 8 : 2 FTOH to PFOA increased this PFOA body burden by 14% (adults) and 17% (2 year-old), suggesting inhalation may also be a meaningful contributor to ionic PFAS exposure through biotransformation.

Personal Strategies to Reduce the Cardiovascular Impacts of Environmental Exposures

Ubiquitous environmental exposures increase cardiovascular disease risk via diverse mechanisms. This review examines personal strategies to minimize this risk. With regard to fine particulate air pollution exposure, evidence exists to recommend the use of portable air cleaners and avoidance of outdoor activity during periods of poor air quality. Other evidence may support physical activity, dietary modification, omega-3 fatty acid supplementation, and indoor and in-vehicle air conditioning as viable strategies to minimize adverse health effects. There is currently insufficient data to recommend specific personal approaches to reduce the adverse cardiovascular effects of noise pollution. Public health advisories for periods of extreme heat or cold should be observed, with limited evidence supporting a warm ambient home temperature and physical activity as strategies to limit the cardiovascular harms of temperature extremes. Perfluoroalkyl and polyfluoroalkyl substance exposure can be reduced by avoiding contact with perfluoroalkyl and polyfluoroalkyl substance-containing materials; blood or plasma donation and cholestyramine may reduce total body stores of perfluoroalkyl and polyfluoroalkyl substances. However, the cardiovascular impact of these interventions has not been examined. Limited utilization of pesticides and safe handling during use should be encouraged. Finally, vasculotoxic metal exposure can be decreased by using portable air cleaners, home water filtration, and awareness of potential contaminants in ground spices. Chelation therapy reduces physiological stores of vasculotoxic metals and may be effective for the secondary prevention of cardiovascular disease.

HNF4A as a potential target of PFOA and PFOS leading to hepatic steatosis: Integrated molecular docking, molecular dynamic and transcriptomic analyses

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are indeed among the most well known and extensively studied Per- and polyfluoroalkyl substances (PFASs), and increasing evidence confirm their effects on human health, especially liver steatosis. Nonetheless, the molecular mechanisms of their initiation of hepatic steatosis is still elusive. Therefore, potential targets of PFOA/PFOS must be explored to ameliorate its adverse consequences. This research aims to investigate the molecular mechanisms of PFOA and PFOS-induced liver steatosis, with emphasis on identifying a potential target that links these PFASs to liver steatosis. The potential target that causes PFOA and PFOS-induced liver steatosis have been explored and determined based on molecular docking, molecular dynamics (MD) simulation, and transcriptomics analysis. In silico results show that PFOA/PFOS can form a stable binding conformation with HNF4A, and PFOA/PFOS may interact with HNF4A to affect the downstream conduction mechanism. Transcriptome data from PFOA/PFOS-induced human stem cell spheres showed that HNF4A was inhibited, suggesting that PFOA/PFOS may constrain its function. PFOS mainly down-regulated genes related to cholesterol synthesis while PFOA mainly up-regulated genes related to fatty acid β-oxidation. This study explored the toxicological mechanism of liver steatosis caused by PFOA/PFOS. These compounds might inhibit and down-regulate HNF4A, which is the molecular initiation events (MIE) that induces liver steatosis.