Serum Perfluorooctanoic Acid Levels Research Articles

Temporal Trend of Serum Perfluorooctanoic Acid and Perfluorooctane Sulfonic Acid among U.S. Adults with or without Comorbidities in NHANES 1999–2018

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are associated with adverse health effects. This study examined the trend of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) levels in individuals with and without pre-existing comorbidities. We analyzed the characteristics of 13,887 participants across nine U.S. NHANES cycles (1999–2000 to 2017–2018) and calculated the geometric mean (GM) of PFOA and PFOS levels, standardized by sex and age. A joinpoint regression model was used to analyze the temporal trends of serum PFOA and PFOS levels. We observed declining PFOA and PFOS serum levels among adults in NHANES from 1999–2000 to 2017–2018. Serum PFOA and PFOS concentrations were higher in men, smokers, and individuals with pre-existing diabetes, CKD, hyperlipidemia, CVD, and cancer. We observed faster decline rates in PFOA levels among individuals with diabetes and CKD and faster decline rates in PFOS levels among individuals with diabetes and those without CKD. This study provided evidence of varying levels and changing trends of PFOA and PFOS between groups with and without established chronic disease, highlighting the role of environmental chemicals in the onset and development of chronic diseases.

Legacy perfluoro-alkyl substances impair LDL-cholesterol uptake independently from PCSK9-function

Perfluoro-alkyl substances (PFAS) are pollutants, whose exposure was associated with altered levels of low-density lipoproteins (LDL) in humans. Here we investigated this clinical outcome in two groups of young male adults residing in areas of respectively low and high environmental exposure to perfluoro-octanoic-acid (PFOA). From the Regional Authority data on pollution areas, 38 not-exposed and 59 exposed age-matched participants were evaluated for serum levels of total cholesterol (Total-Chol), LDL-Chol, high-density lipoprotein cholesterol (HDL-Chol), triglycerides (Tgl) and chromatography quantified PFOA. Human hepato-carcinoma cell line HepG2 was exposed to PFOA or perfluoro-octane-sulfonate (PFOS), as legacy PFAAs, and C6O4 as new generation compound. Fluorimetry was used to evaluate the cell-uptake of labelled-LDL. Proprotein Convertase Subtilisin/Kexin 9 (PCSK9)-mediated LDL-receptor (LDL-R) degradation and sub-cellular localization of LDL-R were evaluated by western blot analysis. Serum levels of PFOA, were positively and significantly correlated with Total-Chol (ρ = 0.312, P = 0.002), LDL-Chol (ρ = 0.333, P = 0.001) and Tgl (ρ = 0.375, P < 0.001). Participants with high serum LDL-Chol and Tgl levels, according to the cardiovascular risk, were more prevalent in exposed compared to not-exposed subjects (respectively: 23.7% vs 5.3%, P = 0.023 and 18,6% vs 0%, P = 0.006). Exposure of HepG2 cells to PFOA or C6O4 100 ng/mL was associated with a significantly lower LDL uptake than controls but no major impact of any PFAAs on PCSK9-mediated LDL-R degradation was observed. Compared to controls, exposure to PFAS showed an unbalanced LDL-R partition between membrane and cytoplasm. Endocytosis inducer sphingosine restored LDL-R partition only in samples exposed to C6O4. These data suggest a novel endocytosis-based mechanism of altered lipid trafficking associated with the exposure to legacy PFAS.

Associations between per- and polyfluoroalkyl substances, liver function, and daily alcohol consumption in a sample of U.S. adults

Background and aimPer- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and in the serum of the U.S. population. We sought to evaluate the association of PFAS independently and jointly with alcohol intake on liver function biomarkers in a sample of the U.S. general population. MethodsUsing data from the National Health and Nutrition Examination Survey (2003–2016; N = 11,794), we examined the five most historically prevalent PFAS with >75% detection rates. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between PFAS (quartiles and log-transformed continuous, ng/mL) and high levels (>95th percentile) of liver injury biomarkers using logistic regression models adjusted for key confounders. We evaluated interactions between PFAS and alcohol consumption and sex via stratified analyses and conducted sub-analyses adjusting for daily alcohol intake among those with available drinking history (N = 10,316). ResultSerum perfluorooctanoic acid (PFOA) was positively associated with high levels of alanine transferase (ALT) without monotonic trend (ORQ4vsQ1 = 1.45, CI: 0.99-2.12; p-trend = 0.18), and with increased aspartate transaminase when modeled continuously (OR = 1.15, CI: 1.02–1.30; p-trend = 0.03). Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) were both inversely associated with alkaline phosphatase while a trend was evident only for PFHxS (p = 0.02). A non-monotonic inverse association was observed with PFOA (p-trend = 0.10). The highest quartile of PFOS was associated with high total bilirubin (TB; ORQ4vsQ1 = 1.57, CI: 1.01–2.43, p-trend = 0.02). No significant associations were found between any PFAS and γ-glutamyl transpeptidase. We found no associations for perfluorodecanoic acid and perfluorononanoic acid. We observed some suggestive interactions with alcohol intake, particularly among heavy drinkers. ConclusionConsistent with other studies, serum levels of PFOA, PFHxS and PFNA were positively associated with high levels of ALT, and we also observed weak positive associations between some PFAS and TB. Associations observed among heavy drinkers warrant additional evaluation.

Effects of perfluorooctanoic acid (PFOA) on gene expression profiles via nuclear receptors in HepaRG cells: Comparative study with in vitro transactivation assays

Perfluorooctanoic acid (PFOA), a synthetic perfluorinated eight-carbon organic chemical, induces hepatotoxicity in rodents, indicated increased liver weight, hepatocellular hypertrophy, necrosis, and peroxisome proliferation. Epidemiological studies have demonstrated the association between serum PFOA levels and various adverse effects. In this study, we investigated the gene expression profiles of human HepaRG cells exposed to 10 and 100 μM PFOA for 24 h. Treatment with 10 and 100 μM PFOA significantly modulated the expression of 190 and 996 genes, respectively. Genes upregulated or downregulated by 100 µM PFOA included peroxisome proliferator-activated receptor (PPAR) signaling genes related to lipid metabolism, adipocyte differentiation, and gluconeogenesis. Moreover, we identified the “Nuclear receptors-meta pathways” following the activation of other nuclear receptors: constitutive androstane receptor (CAR), pregnane X receptor (PXR) and farnesoid X receptor (FXR), as well as the transcription factor nuclear factor E2-related factor 2 (Nrf2). The expression levels of some target genes (CYP4A11, CYP2B6, CYP3A4, CYP7A1, and GPX2) of these nuclear receptors and Nrf2 were confirmed using quantitative reverse transcription polymerase chain reaction. Next, we performed transactivation assays using COS-7 and HEK293 cells to investigate whether these signaling-pathways were activated by the direct effects of PFOA on human PPARα, CAR, PXR, FXR and Nrf2. PFOA concentration-dependently activated PPARα, but not CAR, PXR, FXR, or Nrf2. Taken together, these results suggest that PFOA affects the hepatic transcriptomic responses of HepaRG cells through the direct activation of PPARα and indirect activation of CAR, PXR, FXR, and Nrf2. Our finding indicates that PPARα activation in the “Nuclear receptors-meta pathways” functions as a molecular initiating event for PFOA, and indirect activation of alternative nuclear receptors and Nrf2 also induce important molecular mechanisms in PFOA-induced human hepatotoxicity.

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Vol. 131, No. 6 Research LetterOpen AccessEstimation of Serum PFOA Concentrations from Drinking and Non–Drinking Water Exposures Alexander R. Bogdan, Sarah Fossen Johnson, and Helen Goeden Alexander R. Bogdan Address correspondence to Alexander R. Bogdan, P.O. Box 64975, St. Paul, MN 55164-0975 USA. Email: E-mail Address: [email protected] https://orcid.org/0000-0003-3513-0027 Minnesota Department of Health, St. Paul, Minnesota, USA Search for more papers by this author , Sarah Fossen Johnson Minnesota Department of Health, St. Paul, Minnesota, USA Search for more papers by this author , and Helen Goeden Minnesota Department of Health, St. Paul, Minnesota, USA Search for more papers by this author Published:16 June 2023CID: 067701https://doi.org/10.1289/EHP12405AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit IntroductionConcern has increased over potential human health effects from per- and polyfluoroalkyl substances (PFAS) exposure as more toxicity and exposure data about PFAS have become available. In 2022, the National Academies of Sciences, Engineering, and Medicine (NASEM)1 issued clinical care guidance for patients based on serum levels—the best exposure metric—for the sum of seven PFAS included in the “National Report on Human Exposure to Environmental Chemicals” published by the U.S. Centers for Disease Control and Prevention (U.S. CDC).2 The serum guidelines are a) less than 2 nanograms per milliliter<2 ng/mL, adverse health effects are not expected; b) 2 to 20 nanograms per milliliter2–20 ng/mL, potential adverse effects, especially in sensitive populations; and c) greater than 20 nanograms per milliliter>20 ng/mL, increased risk for adverse effects. Infants and young children have been identified as especially sensitive to PFAS exposure.3 The most recent data (2017–2018) from the National Health and Nutrition Examination Survey (NHANES) reported serum levels in a representative sample of Americans 12 y of age and older for five of the seven PFAS identified by NASEM. The sum of median and 95th percentile serum levels for the five PFAS were 7.37 and 23.87 nanograms per milliliter23.87 ng/mL,4 respectively.The NASEM report also highlighted that multiple exposure routes exist for PFAS and how exposures might be reduced. When contaminated, drinking water can be a significant source of exposure; however, sources such as diet and consumer products predominate in communities where drinking water is not contaminated.4 In the early 2000s, some drinking water sources in Twin Cities East Metro area in Minnesota were found to be contaminated with PFAS.5 Drinking water treatment was initiated in 2006, and water samples taken after installation of treatment systems generally had PFOA concentrations below the limit of detection.In 2008, adult longtime East Metro residents’ mean serum perfluorooctanoic acid (PFOA) level was approximately 15 nanograms per milliliter∼15 ng/mL; by 2014, the mean had fallen by almost two-thirds.5 Significant serum decreases for two other bioaccumulative PFAS—perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS)—were also observed in East Metro residents during this time frame. Adults who moved to the East Metro area after installation of water treatment had serum levels of PFOA, PFHxS, and PFOS similar to those of the corresponding NHANES population. No relationship between duration of residence and serum PFAS was observed for new residents, supporting our hypothesis that the serum levels measured in new residents after the addition of water treatment are predominantly the result of ongoing non–drinking water exposures.5 This study also showed the efficacy of water treatment at reducing serum PFAS levels toward the national median in communities with contaminated drinking water.In this analysis, we demonstrate a method for using chemical-specific toxicokinetic (TK) values to estimate the contribution of drinking water to serum PFOA levels, compare it to non–drinking water exposures, and discuss implications on public health policy.MethodsMean and 95th percentile lifetime water intake rates (WaterIntake) of 0.017 and 0.044 liter per kilogram per day0.044L/kg/d, respectively, from the U.S. Environmental Protection Agency (U.S. EPA)6 were used to estimate daily doses of PFOA from drinking water (perfluorooctanoic acid begin subscript daily water dose end subscriptPFOADailyWaterDose) with varying PFOA water concentrations (perfluorooctanoic acid begin subscript water concentration end subscriptPFOAWaterConc.;0.001 to 100 nanograms per liter0.001–100 ng/L) (Equation 1). PFOADailyWaterDose (ngkg×day)=[PFOAWaterConc.(ngL)×WaterIntake(Lkg×day)] [1] The daily drinking water PFOA doses were divided by the PFOA clearance rate (ClearanceRate) determined by California Environmental Protection Agency (0.28 milliliter per kilogram per day0.28mL/kg/d)7 to estimate serum PFOA levels resulting solely from drinking water exposure (perfluorooctanoic acid begin subscript serum from water end subscriptPFOASerumFromWater) (Equation 2).8PFOASerumFromWater(ngmL)=PFOADailyWaterDose (ngkg×day)÷ ClearanceRate (mLkg×day) [2] These calculations assume long-term exposure, attainment of steady state, and no large PFOA elimination events (e.g., childbirth, breastfeeding).8To estimate total serum PFOA levels (perfluorooctanoic acid begin subscript total serum end subscriptPFOATotalSerum), perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWater was added to the 2017–2018 NHANES median serum level (perfluorooctanoic acid begin subscript uppercase n h a n e s median serum end subscriptPFOANHANESMedianSerum; 1.47 nanograms per milliliter1.47 ng/mL). This scenario assumes negligible PFOA contribution from drinking water at the NHANES median serum PFOA level.PFOA is one of the most well-studied bioaccumulative PFAS chemicals and has well-characterized TK parameters. Although this analysis focuses on PFOA, it can be performed for any PFAS with the appropriate TK data.Results and DiscussionAt steady state, we calculated that serum PFOA increases by approximately 0.06 nanogram per milliliter∼0.06ng/mL (mean water intake) or approximately 0.16 nanogram per milliliter∼0.16ng/mL (95th percentile water intake) per ng/L PFOA in the drinking water (Table 1; Figure 1A). This calculated relationship is consistent with a recently published study that compared PFAS drinking water concentrations to serum levels at four contaminated sites in Sweden.9 Based on empirical data from these sites, serum PFOA increased by 0.05815 nanogram per milliliter0.05815 ng/mL per ng/L PFOA in the drinking water, identical to our calculated ratio using mean water intake.Table 1 Estimated contributions of PFOA from drinking water exposures to total serum PFOA levels.Water PFOA concentration (ng/L)Predicted serum PFOA level (ng/mL)Mean water intake (0.017 liter per kilogram per day0.017L/kg/d)95th percentile water intake (0.044 liter per kilogram per day0.044L/kg/d)perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWaterperfluorooctanoic acid begin subscript total serum end subscriptPFOATotalSerumContribution of water to totalperfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWaterperfluorooctanoic acid begin subscript total serum end subscriptPFOATotalSerumContribution of water to total001.470%01.470%0.0010.000061.470.004%0.000161.470.011%0.010.00061.470.04%0.00161.470.11%0.10.00611.480.41%0.0161.491.1%10.0611.534.0%0.161.639.7%30.181.6511%0.471.9424%4a0.241.7114%0.632.1030%50.301.7717%0.792.2635%100.612.0829%1.573.0452%20b1.212.6845%3.144.6168%402.433.9062%6.297.7681%1006.077.5481%15.7117.1891%Note: Predicted contributions to serum PFOA exclusively from drinking water (perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWater) were calculated by first establishing a daily PFOA dose by multiplying the water PFOA concentration by the mean and 95th percentile lifetime water intake rates from the U.S. EPA Exposures Factors Handbook. The daily PFOA dose was then divided by the PFOA clearance rate (0.28 milliliter per kilogram per day0.28mL/kg/d) from California Environmental Protection Agency to calculate perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWater. perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWater was added to the 2017–2018 NHANES median serum PFOA concentration (1.47 nanograms per milliliter1.47 ng/mL), representing non–drinking water PFOA exposures, to generate a total PFOA serum level (perfluorooctanoic acid begin subscript total serum end subscriptPFOATotalSerum) inclusive of both drinking water and non–drinking water PFOA exposures. The contribution percentage of PFOA-containing drinking water to total PFOA exposure at each water PFOA concentration was calculated by dividing perfluorooctanoic acid begin subscript serum form water end subscriptPFOASerumFromWater by perfluorooctanoic acid begin subscript total serum end subscriptPFOATotalSerum and multiplying by 100. U.S. EPA, U.S. Environmental Protection Agency; MCL, Maximum Contaminant Limit; NHANES, National Health and Nutrition Examination Survey; PFOA, perfluorooctanoic acid; UCMR3, Third Unregulated Contaminant Monitoring Rule; UCMR5, Fifth Unregulated Contaminant Monitoring Rule.aProposed MCL and UCMR5 Reporting Limit.bUCMR3 Reporting Limit.Figure 1. Predicted contributions of PFOA in drinking water on serum PFOA levels. (A) Predicted impact on serum PFOA levels exclusively from long-term consumption of drinking water with varying PFOA concentrations. Predicted serum PFOA levels were calculated for lifetime mean water intake (0.017 liter per kilogram per day0.017L/kg/d; blue circles and line) and lifetime 95th percentile intake (0.044 liter per kilogram per day0.044L/kg/d; orange squares and line) from the U.S. EPA Exposures Factors Handbook. Scenario assumes drinking water is the only source of PFOA exposure. (B) Predicted impact on total serum PFOA level from long-term consumption of PFAS-containing drinking water. Serum PFOA levels calculated in (A) were added to the 2017–2018 NHANES median serum level. Scenario assumes 2017–2018 NHANES median serum level is due to non–drinking water exposures. The red dotted line demarcates the NASEM border between no expected health effects (less than 2 nanograms per milliliter<2 ng/mL) and potential for health effects in sensitive populations (greater than or equal to 2 nanograms per milliliter≥2 ng/mL). All inputs and predicted levels are shown in Table 1. Note: NASEM, National Academies of Science, Engineering, and Mathematics; NHANES, National Health and Nutrition Examination Survey; PFAS, per- and polyfluoroalkyl substances; PFOA, perfluorooctanoic acid; U.S. EPA, U.S. Environmental Protection Agency.Assuming PFOA exposure occurred exclusively via drinking water, the NHANES median serum level (1.47 nanograms per milliliter1.47 ng/mL) would not be reached until the drinking water PFOA concentration was approximately 30 nanograms per liter∼30 ng/L (mean water intake) or approximately 10 nanograms per milliliter∼10 ng/mL (95th percentile water intake). In the U.S. EPA’s Unregulated Contaminant Monitoring Rule 3, only 2% of tested public water supplies had PFOA greater than 20 nanograms per liter>20 ng/L,10 suggesting drinking water is not the major contributor to the NHANES median.The contribution of drinking water exposures to total serum PFOA was also evaluated. At 1 nanogram per liter1 ng/L, drinking water is estimated to contribute approximately 4 percent∼4% (mean water intake) and approximately 10 percent∼10% (high-end water intake) of total serum PFOA. PFOA drinking water concentrations below 0.1 nanogram per liter0.1 ng/L were calculated to have a negligible contribution (less than or equal to 1 percent≤1%) to total serum PFOA at steady state (Table 1; Figure 1B).The U.S. EPA has proposed a Maximum Contaminant Level (MCL) for PFOA of 4 nanograms per liter4 ng/L,3 the lowest concentration that the U.S. EPA determined that PFOA can be reliably quantified. Drinking water containing PFOA at 4 nanograms per liter4 ng/L would contribute approximately 14 percent∼14% (mean intake) and approximately 30 percent∼30% (high-end intake) to the total serum PFOA level.Reducing PFOA exposures has broad public health impacts. This analysis indicates that, unless non–drinking water exposures are also addressed, treating drinking water to concentrations below 1 nanogram per liter1 ng/L PFOA would have limited impact on lowering current serum PFOA levels in the United States. PFAS-contaminated sites should be remediated and drinking water containing PFAS should be treated; however, to achieve meaningful reductions in serum PFAS, a comprehensive national approach must be undertaken to reduce PFAS exposures from all sources, including banning PFAS in food, consumer products, and other nonessential uses.AcknowledgmentsThe authors would like to acknowledge support by the Clean Water Fund, funded by the 2008 Minnesota Clean Water, Land and Legacy Amendment. The authors also want to thank staff at the Minnesota Department of Health and the Minnesota Pollution Control Agency for their helpful comments on this analysis and manuscript.

Perfluoroalkyl substance exposure is associated with asthma and innate immune cell count in US adolescents stratified by sex.

Exposure to perfluoroalkyl substances (PFAS) may be harmful to humans; however, previous studies have been inconsistent regarding the potential for PFAS-induced immunosuppresion. This study explored the relationship between PFAS exposure and risks of asthma, wheezing, and immunosuppression in 12-19year-olds using the National Health and Nutrition Examination Survey (NHANES) data. Logistic regression models were used to reveal associations between serum PFAS levels and risks of asthma, wheezing, asthma attack, and emergency department visits. Pearson's correlation was used to determine the relationship between serum PFAS levels and leukocyte count. Data were also stratified by sex. We found that medium-low levels of serum perfluorooctane sulfonate (PFOS) (6.90-12.40ng/mL) and serum perfluorooctanoic acid (PFOA) (2.43-3.60ng/mL) were negatively related, respectively, to current asthma and wheezing in boys, and to wheezing in girls. Meanwhile, boys with medium-high levels (1.50-3.00ng/mL) of serum perfluorohexanesulfonate (PFHxS) had a high risk of wheezing. Among asthmatic participants, both medium-high levels (3.75-5.07ng/mL) of serum PFOA and high levels (> 3.92ng/mL) of PFHxS correlated with asthma attacks in boys; likewise, medium-low levels (0.70-0.99ng/mL) of serum PFNA correlated with asthma attacks in girls. Also, PFOA and PFNA levels were weakly positively correlated with basophil count, whereas PFOS levels were weakly negatively correlated with eosinophils in asthmatic boys, indicating that basophils may be important in the immune response to PFAS exposure among asthmatics.

Prevalence and predictors of per- and polyfluoroalkyl substances (PFAS) serum levels among US volunteer firefighters

BACKGROUND AND AIM: Per- and polyfluoroalkyl substances (PFAS) are synthetic persistent compounds of health concern. Firefighters may be exposed to PFAS through firefighting foams, combustion products, and equipment/gear. Studies have shown elevated PFAS levels in paid firefighters. Few studies include volunteer firefighters, who comprise 67% of US firefighters. We assessed seroprevalence and predictors of PFAS levels among US volunteer firefighters enrolled in the Firefighter Cancer Assessment and Prevention Study (CAPS), a research partner of the Fire Fighter Cancer Cohort Study (FFCCS). METHODS: Consenting firefighters (n=413) enrolled from 34 volunteer departments in four US states - Connecticut (CT), Maine (ME), Maryland (MD), and New Jersey (NJ). Participants completed a survey and provided blood samples, analyzed for PFAS by online solid phase extraction unit and HPLC-MS/MS instrumentation. We calculated prevalence and geometric means by location (a single NJ department (NJ-Dept1), NJ-Other, CT&amp;#x26;MD, ME). For select PFAS (prevalence &amp;#x2265;75%), we assessed associations between PFAS (log-transformed) and age, firefighting years, monthly responses, and location in single-PFAS multivariate models. RESULTS: Most participants were non-Hispanic White (91%), male (92%), with an average age of 45.2 years (sd 15.4) and 20.2 years (sd 15.7) of firefighting. Serum levels of the six PFAS were similar between locations, except perfluorodecanoic acid (PFDeA) was significantly higher in NJ-Dept1 than elsewhere (0.25ug/L, vs 0.08, 0.09, 0.08; p&amp;#x3c;0.0001) and perfluorooctanoic acid (PFOA) was higher in NJ-Other than elsewhere (2.35ug/L vs 1.96, 1.23, 1.29; p&amp;#x3c;0.0001). In multivariate analysis, PFOA and PFDeA were positively associated with age (p=0.006, 0.0736, respectively) and location (p&amp;#x3c;0.0001 (for all locations, ref = NJ-Dept1)), controlling for firefighting years and monthly responses. CONCLUSIONS: We observed spatial differences in volunteer firefighters’ serum PFOA and PFDeA levels. Further research is needed to better understand sources of PFAS among volunteer firefighters, including their primary occupations and community exposures. KEYWORDS: PFAS, firefighters, volunteers

Risk assessment for PFOA and kidney cancer based on a pooled analysis of two studies.

Perfluorooctanoic acid (PFOA) has been associated with kidney cancer in human studies. We conducted a pooled analysis of two large studies of PFOA and renal cell carcinoma (RCC, the most common type of kidney cancer); one from the National Cancer Institute (NCI) (324 cases and controls), and a second from the C8 Science Panel (103 cases and 511 controls). Serum PFOA levels were estimated a median of 8years before diagnosis. Analyses were conducted via conditional logistic regression. Lifetime risk of kidney cancer per unit serum PFOA concentration and per unit dose were calculated. The 25th, 50th and 75th percentiles of serum PFOA levels were 4.8, 7.3, and 23.9ng/ml for the pooled analysis. The preferred model for the pooled datawas a two-piece linear spline model (knot at 12.5ng/ml serum PFOA); the log odds of RCC increased 0.1349 per 1ng/ml increase in serum PFOA up to the knot (eg, an OR of 2.02 (1.45-2.80) from the median to the knot), and was flat thereafter. The estimated lifetime excess risk (cancer slope factor) with an exposure of 1ng/ml was 0.0018, similar to the excess risk of 0.0026 recently reported by CalEPA based on different methods. Assuming a serum half-life of 2.3years and a distribution volume of 170ml/kg for PFOA, our results are equivalent to 0.0128 per ng/kg/d of PFOA intake. To limit excess lifetime kidney cancer risk to 1/1,000,000, our data suggest a limit of 0.0015ng/L (0.0015 ppt) for PFOA in drinking water, similar to CalEPA's proposed Public Health Goal and the new US EPA Drinking Water Health Advisory. Our results correspond reasonably well with cancer slope factors developed by other investigators using published summary data, and suggest drinking water limits similar to new recommendations by the US EPA.

Associations of serum PFOA and PFOS levels with incident hypertension risk and change of blood pressure levels

Evidence on the associations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) with hypertension or blood pressure (BP) levels was limited and inconsistent. The present prospective study aims to evaluate the longitudinal associations of serum levels of PFOA and PFOS with incident hypertension risk and change of blood pressure levels. At baseline 1080 participants (mean age 62 years, 58.9% females) free of hypertension, cardiovascular disease, diabetes, and cancer were followed up for nearly 5 years. Baseline serum levels of PFOA and PFOS were measured with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Hypertension was defined as any of (1) self-reported physician-diagnosed hypertension (2) use of hypotension drugs (3) measured systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg. Change of BP was evaluated as a difference between twice measurements (BP at follow-up visit－BP at baseline). After adjustment for multiple covariates, serum PFOS levels were negatively correlated with risk of hypertension [RR per lg-unit = 0.94 (95% CI: 0.88, 0.99)] and change of systolic BP [β = −1.48 (95% CI: −2.56, −0.41)]. The highest vs lowest quartiles of PFOS concentration was negatively associated with hypertension risk. Compared with Q1, the RRs (95% CIs) for Q2, Q3, and Q4 were 0.83 (0.67–0.98), 0.81 (0.67–0.97), and 0.81(0.67–0.97), respectively (p for trend = 0.016). The negative associations remained in females but not in males (p for interaction = 0.44). No significant association of PFOA with hypertension risk was observed. Further studies are needed to validate our findings.

Risk of Cancer in a Community Exposed to Per- and Poly-Fluoroalkyl Substances.

Background:Per- and polyfluoroalkyl substances (PFAS) emissions from a plastic coating industrial source in southern New Hampshire (NH) have contaminated at least 65 square miles of drinking water. Prior research indicates that high levels of PFAS are associated with a variety of adverse health outcomes, including an increased risk of cancer. Reports indicate that mean blood serum levels of perfluorooctanoic acid (PFOA), one type of PFAS, in residents of the exposed community are more than 2 times greater than the mean blood serum level in the US. Merrimack public water supply customers also have higher average blood levels of perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) than the time—matched US average. A 2018 report concludes that the incidence rate of cancer in Merrimack does not exceed the incidence rate of cancer in NH in general. However, prior reporting on the risk of cancer in Merrimack is compared only to a state-wide metric influenced by the Merrimack cancer incidence.Methods:Our ecological study compared the risk in Merrimack, NH residents for 24 types of cancer between 2005 and 2014, targeted in a previous study, and all-cause cancers, to US national cancer rates and cancer rates in demographically similar towns in New England. Four New England “unexposed towns” were chosen based on demographic similarity to Merrimack, with no documented PFAS exposure in water supplies. We utilized unadjusted logistical regression to approximate risk ratios (RR) and 95% confidence intervals (CI) assessing the risk of cancer in Merrimack NH to each of the 4 comparator communities, the pooled comparator variable, and national average incidence.Results:Residents of Merrimack, NH experienced a significantly higher risk of thyroid cancer (RR = 1.47, 95% CI 1.12-1.93), bladder cancer (RR = 1.45, 95% CI 1.17-1.81), esophageal cancer (RR = 1.71, 95% CI 1.1-2.65), and mesothelioma (RR = 2.41, 95% CI 1.09-5.34), compared to national averages. Our work also suggests that Merrimack residents experienced a significantly higher risk of all-cause cancer (RR = 1.34, 95% CI 1.25-1.43), thyroid cancer (RR = 1.69, 95% CI 1.19-2.39), colon cancer (RR = 1.27, 95% CI 1.02-1.57), and prostate cancer (RR = 1.36, 95% CI 1.15, 1.6) compared with similarly exposed New England communities. Our results indicate that residents of Merrimack may also have a significantly lower risk of some site-specific cancers compared to national averages, including lower risk of prostate cancer (RR = 0.57, 95% CI 0.5-0.66), female breast cancer (RR = 0.60, 95% CI 0.52-0.68), ovarian cancer (RR = 0.52, 95% CI 0.33-0.84) and cervical cancer (RR = 0.29, 95% CI 0.12-0.69).Conclusion:Merrimack residents experienced a significantly higher risk of at least 4 types of cancer over 10 years between 2005 and 2014. Merrimack is a community with documented PFAS contamination of drinking water in public and private water sources. Results indicate that further research is warranted to elucidate if southern NH residents experience increased risk for various types of cancer due to exposure to PFAS contamination.

Per- and polyfluoroalkyl substance (PFAS) exposure, maternal metabolomic perturbation, and fetal growth in African American women: A meet-in-the-middle approach.

Prenatal exposures to per- and polyfluoroalkyl substances (PFAS) have been linked to reduced fetal growth. However, the detailed molecular mechanisms remain largely unknown. This study aims to investigate biological pathways and intermediate biomarkers underlying the association between serum PFAS and fetal growth using high-resolution metabolomics in a cohort of pregnant African American women in the Atlanta area, Georgia. Serum perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) measurements and untargeted serum metabolomics profiling were conducted in 313 pregnant African American women at 8-14weeks gestation. Multiple linear regression models were applied to assess the associations of PFAS with birth weight and small-for-gestational age (SGA) birth. A high-resolution metabolomics workflow including metabolome-wide association study, pathway enrichment analysis, and chemical annotation and confirmation with a meet-in-the-middle approach was performed to characterize the biological pathways and intermediate biomarkers of the PFAS-fetal growth relationship. Each log2-unit increase in serum PFNA concentration was significantly associated with higher odds of SGA birth (OR=1.32, 95% CI 1.07, 1.63); similar but borderline significant associations were found in PFOA (OR=1.20, 95% CI 0.94, 1.49) with SGA. Among 25,516 metabolic features extracted from the serum samples, we successfully annotated and confirmed 10 overlapping metabolites associated with both PFAS and fetal growth endpoints, including glycine, taurine, uric acid, ferulic acid, 2-hexyl-3-phenyl-2-propenal, unsaturated fatty acid C18:1, androgenic hormone conjugate, parent bile acid, and bile acid-glycine conjugate. Also, we identified 21 overlapping metabolic pathways from pathway enrichment analyses. These overlapping metabolites and pathways were closely related to amino acid, lipid and fatty acid, bile acid, and androgenic hormone metabolism perturbations. In this cohort of pregnant African American women, higher serum concentrations of PFOA and PFNA were associated with reduced fetal growth. Perturbations of biological pathways involved in amino acid, lipid and fatty acid, bile acid, and androgenic hormone metabolism were associated with PFAS exposures and reduced fetal growth, and uric acid was shown to be a potential intermediate biomarker. Our results provide opportunities for future studies to develop early detection and intervention for PFAS-induced fetal growth restriction.

Associations between serum PFOA and PFOS levels and incident chronic kidney disease risk in patients with type 2 diabetes

Chronic kidney disease (CKD) is a common comorbidity among patients with type 2 diabetes. Exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) has been linked to poorer kidney function in general population, but the related studies in individuals with diabetes were very limited. We aimed to examine the longitudinal associations of PFOA and PFOS exposure and CKD incidence among diabetes patients. Baseline levels of PFOA and PFOS were measured in serum in 967 diabetes patients from the Dongfeng-Tongji cohort. Multivariable logistic regression models were used to characterize the relationship between serum PFOA and PFOS levels and incident CKD risk (defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2). During 10-years follow-up, 267 incident CKD cases were identified. Only PFOS level was significantly associated with lower risk of CKD incidence (adjusted OR: 0.67; 95%CI: 0.51, 0.88). Such inverse association was only observed among participants with lower eGFR levels (< 70 mL/min/1.73 m2), although the interaction did not achieve statistical significance. Notably, an inverted U-shaped relationship between eGFR and serum PFOS level (Pfor nonlinearity < 0.001) was observed based on the 1825 subjects with available data at baseline. PFOS exposure was negatively associated with CKD incidence in patients with diabetes, especially in those with baseline eGFR levels < 70 mL/min/1.73 m2. This may be explained by the implication of baseline kidney function on the serum PFAS concentrations which in turn affect the relationship between PFOS exposure and the incident CKD risk among diabetes.

Perfluoroalkyl substances and thyroid stimulating hormone levels in a highly exposed population in the Veneto Region

BackgroundPer- and poly-fluoroalkyl substances (PFAS) are persistent and widespread environmental pollutants. People living in Veneto Region (Italy) have been exposed from the late 1970s to 2013 to elevated concentrations of PFAS through drinking water. The effect of PFAS on thyroid function is still controversial and studies focusing on thyroid stimulating hormone (TSH) have shown inconsistent results. The aim of this study was to evaluate the association between serum PFAS and TSH levels and its dose-response relationship in a large population of highly exposed individuals. MethodsA cross-sectional study was conducted on 21,424 individuals aged 14–39 living in the contaminated area. In the main analysis, participants with prevalent thyroid disease and pregnant women were excluded. Serum levels of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) were measured. Generalized Additive Models were used to evaluate the association between TSH levels and serum PFAS, using thin plate spline smooth terms to model the potential non-linear relationship. Models were stratified by sex and age group and adjusted for potential confounders. A secondary analysis was conducted to evaluate the association between PFAS with prevalent self-reported thyroid disorders. ResultsWe found no association between TSH and any type of PFAS among adolescents or women. A decrease in TSH concentration was observed in association with an IQR increase in PFHxS and a mild decrease in TSH at low levels of PFOA, PFOS and PFHxS among male adults. Self-reported thyroid disease was more common among women with higher levels of PFNA concentrations, whereas all other PFAS were not associated with thyroid diseases regardless of sex or age. ConclusionsOverall there is no evidence of an association between TSH and PFAS. However, some results are suggestive of a possible inverse association of TSH with PFOA, PFOS and PFHxS among adult males.

Serum levels of perfluorooctanoic acid and perfluorooctane sulfonic acid in pregnant women: Maternal predictors and associations with birth outcomes in the PIPA Project.

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent pollutants associated with adverse birth outcomes. This study aimed to identify predictors of blood PFOA and PFOS concentrations in pregnant women and to estimate their associations with birth outcomes in Brazil. We conducted a cross-sectional study with 139 pregnant women enrolled in the pilot study of the Rio Birth Cohort Study on Environmental Exposure and Childhood Development (PIPA Project). Multiple linear regression was used to estimate associations between PFOA and PFOS with maternal predictors and birth outcomes. Higher levels of PFOA were observed in women aged 16-19 and 20-39 years, while fish consumption from 0.6 to 2.0 times per week was associated with lower levels of the substance. PFOS levels were higher in women living in houses with up to four rooms but lower in those who reported passive exposure to smoking. Increased newborn length and head circumference were also associated with higher maternal levels of PFOA. In our study, age, fish consumption, passive smoking, and the number of rooms in the house were predictors of maternal PFAS levels. However, we did not observe significant associations between maternal plasma PFAS concentrations and birth outcomes.

Metabolic Perturbation Associated with Per- and Polyfluoroalkyl Substances (PFAS) in an African American Pregnancy Cohort

Background. Per- and polyfluoroalkyl substances (PFASs) are suspected developmental toxicants that are ubiquitous and persistent in the environment. Exposures to PFASs during the prenatal period have been linked to adverse pregnancy and birth outcomes. Notably, communities of color and those affected by socioeconomic disadvantage, particularly African American (AA) pregnant women, disproportionately experience high levels of PFAS exposure and adverse health outcomes. Mechanisms underlying these relationships are complex and largely unknown. Methods. We used metabolomics, a high-throughput analytical method involving the identification and quantification of thousands of metabolic features associated with exogenous exposure and endogenous processes, to address these knowledge gaps. We measured serum levels of 12 PFAS and conducted high-resolution metabolic profiling on 320 maternal serum samples collected during the first trimester of pregnancy from Atlanta African American Maternal-Child cohort participants. We conducted untargeted Metabolome Wide Association Study (MWAS) to detect metabolic perturbations associated with PFAS exposures and explore underlying molecular mechanisms. Results. The average serum levels of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were 0.94±0.57 and 3.28±1.67 ng/mL, respectively. In total, 29,524 metabolic features have been reliably extracted from two technical columns. Using multivariate linear regression models, we found 125 metabolic features were significantly associated with one or more PFAS, when controlling for covariates and false positive discovery rate. Pathway analysis indicated several oxidative stress and inflammatory pathways associated with PFAS exposures, including aspartate, arginine, and glycosphingolipid metabolism. We validated five metabolites using authentic chemical reference standards, including aspartate and arginine, which are both significantly associated with PFOA, PFOS, and perfluorononanoic acid (PFNA). Conclusions. Using untargeted MWAS, we identified and verified several pathways and metabolites associated with PFAS exposures among AA pregnant women, which offer promising initial evidence to examine the underlying molecular mechanisms and provide opportunities for interventions to improve outcomes in exposed mothers and children.

Exposure to perfluoroalkyl substances and thyrotropin levels in an exposed young adult population in the Veneto Region

Background: Perfluoroalkyl substances (PFASs) are persistent and widespread environmental pollutants. People living in the North-East of Italy have been exposed from the late 1970s to 2013 to high concentrations of PFASs through drinking water. The role PFASs could play on thyroid function is still controversial and studies that focused on thyrotropin (TSH) showed inconsistent results. The aim of this study was to evaluate the association between serum PFASs and TSH levels and its dose-response shape in a large exposed population. Methods: A cross-sectional study was conducted in 14,993 individuals aged 20-39 living in the contaminated area. In the main analysis, patients with thyroid pathologies and pregnant women were excluded. Serum levels of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) were measured by HPLC-MS/MS. Generalized Additive Models were used to evaluate the association between TSH levels and serum PFASs, using thin plate spline smooth terms to model the potential non-linear relationship. Models were stratified by gender and adjusted for potential confounders. A secondary analysis was conducted to evaluate the association between PFASs and the prevalence of self-reported thyroid disorders. Results: In both males and females, a statistically significant non-linear association was found with PFOS. The shape of the slopes shows a decrease in TSH concentration at low levels of PFOS but an increase at higher serum PFOS. PFOA in females was instead found to have a modest linear positive association with TSH. No association was found between TSH and PFNA or PFHxs. We also found higher odds of reporting thyroid disease with increased measured PFNA concentrations in women. Conclusions: Serum PFASs concentrations were modestly associated with thyroid function in this highly exposed young adults population suggesting this substance to be a possible endocrine disruptor. There is evidence of a non-linear association with TSH for PFOS.

Abstract A52: Targeted expression profiling identifies mechanisms of potential breast carcinogens

Abstract Over 200 chemicals have been associated with altered mammary gland development and cancer in rodent studies, yet the molecular mechanisms by which this diverse set of chemicals affect the breast remain poorly understood. We examined gene expression profiles of eight known and suspected mammary toxicants using the TempO-Seq platform and a targeted gene expression panel, Breast Carcinogen Screen (BCScreen). The BCScreen panel has 500 genes with at least 30 genes strongly associated with each of the 14 biologic processes relevant to breast cancer and mammary gland development. We compared gene expression profiles in MCF-7 cells treated for 24hrs with four concentrations (1 nM to 10 uM) of the following chemicals: three estrogenic chemicals (genistein, bisphenol A, butyl benzyl phthalate); the selective estrogen receptor modulator, tamoxifen (TAM); 1,4 benzoquinone (BQ), a genotoxic metabolite of the rodent mammary carcinogen benzene; perfluorooctanoic acid (PFOA), a persistent pollutant that alters mammary gland development; and two closely related perfluorinated chemicals that have not been evaluated for mammary toxicity/effects (PFHXA, PFNA). We identified expression patterns activated by mammary toxicants with known ER agonist activity (genistein, BPA, BBP). Some of these genes were suppressed by PFOA and BQ and TAM, mammary toxicants with antagonist or no known direct ER activity. The known weak estrogens genistein, BPA, and BBP had similar gene expression profiles and were enriched for genes associated with cell cycle and DNA repair, particularly at higher doses. Notably, PFOA, Tam, and BQ had greater gene expression changes at lowest (1nM) vs. higher doses and were enriched for genes associated with cell cycle. For context, serum PFOA levels in the general US population are generally five to ten times higher than the 1 nM dose where we observed these changes (i.e., &amp;gt; 0.4 micrograms/L). PFOA profiles were enriched for several transcription factors including E2F1 and E2F4, which regulate cell cycle genes and important processes in mammary development and tumor progression. Utilizing the BCScreen gene panel, we have identified mechanistic targets relevant to breast cancer that are perturbed by mammary toxicants. Citation Format: Vanessa Y. De La Rosa, Erik Lehnert, Marko Milanovic, Chris Vulpe, Ruthann A. Rudel. Targeted expression profiling identifies mechanisms of potential breast carcinogens [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr A52.

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorononanoic acid (PFNA) increase triglyceride levels and decrease cholesterogenic gene expression in human HepaRG liver cells

Per- and polyfluoroalkyl substances (PFASs) are omnipresent in the environment, food chain, and humans. Epidemiological studies have shown a positive association between serum levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), and increased serum cholesterol and, in some cases, also triglyceride levels. However, causality has been questioned, as animal studies, as well as a human trial, showed a decrease in serum cholesterol and no effects or a decrease in plasma triglycerides. To obtain more insight into the effects of PFASs on these processes, the present study investigated the effects of PFOA, PFOS, and perfluorononanoic acid (PFNA) on intracellular triglyceride and cholesterol levels in human HepaRG liver cells. DNA microarray analyses were performed to provide insight into underlying mechanisms. All PFASs induced an increase in cellular triglyceride levels, but had no effect on cholesterol levels. Gene set enrichment analysis (GSEA) of the microarray data indicated that gene sets related to cholesterol biosynthesis were repressed by PFOA, PFOS, and PFNA. Other gene sets commonly affected by all PFAS were related to PERK/ATF4 signaling (induced), tRNA amino-acylation (induced), amino acid transport (induced), and glycolysis/gluconeogenesis (repressed). Moreover, numerous target genes of peroxisome proliferator-activated receptor α (PPARα) were found to be upregulated. Altogether, the present study shows that PFOA, PFOS, and PFNA increase triglyceride levels and inhibit cholesterogenic gene expression in HepaRG cells. In addition, the present study indicates that PFASs induce endoplasmic reticulum stress, which may be an important mechanism underlying some of the toxic effects of these chemicals.

Intrauterine exposure to perfluorinated compounds and overweight at age 4: A case-control study.

The aims were to investigate the association between maternal serum levels of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS) and perfluorononanoic acid (PFNA) in early pregnancy and overweight in the child at 4 years and to assess potential heterogeneity in exposure effect between strata with different levels of other risk factors for overweight. We used a case-control design and included 354 cases (ISO-BMI ≥ 18 kg/m2) and 2 controls per case (ISO-BMI ≤17 kg/m2) from child health care centers in Malmö, Sweden. Controls were selected stratified on risk scores for overweight in a propensity score framework. Maternal serum levels were analyzed in biobanked samples collected by routine around gestational week 14. Logistic regression was used to estimate odds ratios between quartiles of maternal serum levels and child overweight at age 4. There were no consistent monotonic exposure-response relationships. We found some significant odds ratios in specific quartiles but these were regarded as spurious findings. The absence of an effect was consistent over risk strata. We did not find evidence of an association between maternal serum levels of PFOS, PFOA, PFHxS and PFNA in early pregnancy and child overweight at age 4. The level of other risk factors for overweight did not affect children's susceptibility to prenatal PFAS exposure.

Dietary Habits Related to Food Packaging and Population Exposure to PFASs.

Background:Per- and polyfluoroalkyl substances (PFASs) are common industrial and consumer product chemicals with widespread human exposures that have been linked to adverse health effects. PFASs are commonly detected in foods and food-contact materials (FCMs), including fast food packaging and microwave popcorn bags.Objectives:Our goal was to investigate associations between serum PFASs and consumption of restaurant food and popcorn in a representative sample of Americans.Methods:We analyzed 2003–2014 serum PFAS and dietary recall data from the National Health and Nutrition Examination Survey (NHANES). We used multivariable linear regressions to investigate relationships between consumption of fast food, restaurant food, food eaten at home, and microwave popcorn and serum levels of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanesulfonic acid (PFOS).Results:Calories of food eaten at home in the past 24 h had significant inverse associations with serum levels of all five PFASs; these associations were stronger in women. Consumption of meals from fast food/pizza restaurants and other restaurants was generally associated with higher serum PFAS concentrations, based on 24-h and 7-d recall, with limited statistical significance. Consumption of popcorn was associated with significantly higher serum levels of PFOA, PFNA, PFDA, and PFOS, based on 24-h and 12-month recall, up to a 63% (95% CI: 34, 99) increase in PFDA among those who ate popcorn daily over the last 12 months.Conclusions:Associations between serum PFAS and popcorn consumption may be a consequence of PFAS migration from microwave popcorn bags. Inverse associations between serum PFAS and food eaten at home—primarily from grocery stores—is consistent with less contact between home-prepared food and FCMs, some of which contain PFASs. The potential for FCMs to contribute to PFAS exposure, coupled with concerns about toxicity and persistence, support the use of alternatives to PFASs in FCMs. https://doi.org/10.1289/EHP4092