Search

Introduction: Several cross-sectional studies have linked perfluoroalkyl substances (PFAS) to prevalence of menopause. These findings might be influenced by reverse causation mechanism, making longitudinal studies more suitable. However, existing longitudinal studies are limited and present conflicting results., Aim: This study investigates the association between PFAS and both prevalence and incidence of menopause, using longitudinal designs to limit the impact of reverse causation., Methods: A surveillance program on a PFAS highly exposed population in the Veneto region started in 2017 with two rounds of screening, on average 3.8 years apart. Women who participated in the first screening (n = 11,046) were included in the cross-sectional analysis. Multivariate logistic regression models were used to estimate the Odds Ratios (ORs) of menopause associated with exposure to different PFAS. For incidence analysis a retrospective-prospective design used PFOA concentrations reconstructed to 2013 (n = 8536), and a prospective design involved women participating in both screenings (n = 1709), evaluating their baseline concentrations of PFOA, PFOS, and PFHxS. Cox proportional hazards models with age as the timescale were used to estimate Hazard Ratios (HRs), adjusting for sociodemographic and lifestyle factors., Results: Increased menopause prevalence was associated with higher ln-concentrations of PFOA, PFOS, and PFHxS, with ORs of 1.31 (CI: 1.25-1.38), 1.51 (CI: 1.38-1.66), and 1.42 (CI: 1.34-1.51), respectively. The retrospective-prospective study showed increased risk of menopause in higher PFOA reconstructed quartiles, with HRs of 1.01 (CI: 0.87-1.18), 1.17 (CI: 1.02-1.37), and 1.07 (CI: 0.93-1.23) for the second, third and fourth quartiles. The prospective longitudinal study found no association between PFAS and menopause onset., Conclusions: Our results showed a strong cross-sectional association between PFAS exposure and menopause, a weak positive association in the retrospective-prospective study, and no association in the prospective study. This suggests that cross-sectional associations may largely result from reverse causality due to early menopause on reducing PFAS excretion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Epidemiological studies highlight the presence of associations between per- and polyfluoroalkyl substances (PFAS) exposure with liver damage. In 2013, PFAS contamination was discovered in Veneto (Italy), leading to the implementation of a Surveillance Program (SP). Our objective is to investigate the association between PFAS exposure and biomarkers of liver function using single-pollutant and mixture approaches, while exploring the sex-specific differences and the mediating role of obesity in the association., Methods: The study included 42,094 subjects aged ≥20 years participating in the SP. We used generalized additive models to investigate the association between several PFAS and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, adjusting for possible confounders and stratifying by sex. Results were back-transformed to show predicted percentage changes in outcomes per ln-unit increase in PFAS levels; furthermore, we explored the role of BMI in the abovementioned causal pathway, considering it as a potential confounder or mediator PFAS joint effect was investigated using Quantile G-computation., Results: One ln-unit increase in PFHxS concentrations was associated with a 1.49% (95%CI: 0.87, 2.12) and a 0.84% (95% CI: 0.27, 1.40) increase in ALT levels, in males and females respectively; one ln-unit increase in PFOA concentrations was associated with a 1.03% (95%CI: 0.50, 1.55) increase in ALT levels in males, and a 0.52% (95% CI: 0.22, 0.82) and a 0.60% (95% CI: 0.25, 0.96) increase in AST levels in females and males. PFOS showed no association with ALT and AST levels. Quantile G-computation revealed that an interquartile increase in the PFAS mixture was associated with a 3.02% increase (95% CI: 1.65, 4.43) and a 1.65% (95% CI: 0.77, 2.5) increase in ALT levels, in females and males. Mediation analysis suggested that BMI suppressed the association between PFAS and ALT levels, with positive direct effects higher than the total effects., Conclusion: Our findings suggest sex-specific associations between PFAS exposure and liver function biomarkers and underscore the need for additional studies on potential mediators., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Perfluoroalkyl substances (PFAS) have been consistently associated with cardio-metabolic traits. Occupational exposures to multiple PFAS with health outcomes have been poorly investigated. The aim of the present study was to examine these associations among former workers involved in PFAS production., Methods: We considered 232 male ex-employees who had worked in a factory (Trissino, Veneto Region, Italy), which produced PFAS and other chemicals during 1968-2018. Out of twelve serum PFAS, only four (PFOA, PFOS, PFHxS, and PFNA) were quantifiable in at least 50% of samples. Non-fasting serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. The associations between serum PFAS mixture and considered outcomes were assessed through linear regression mixed models and Weighted Quantile Sum (WQS) regression, adjusting for potential confounders., Results: PFOA was detected at the highest level, with a median concentration (in ng/mL) of 80.8 (min-max: 0.35-13,033), followed by PFOS (median: 8.55, min-max: 0.35-343), PFHxS (median: 6.8, min-max: 0.35-597) and PFNA (median: 0.8, min-max: 0.35-5). We observed that each A quartile increase in the WQS index was positively associated with the levels of TC (β: 8.41, 95% IC: 0.78-16.0), LDL-C (β: 8.02, 95% IC: 1-15.0) and SBP (β: 3.21, 95% IC: 0.82-5.60). No association of serum PFAS concentration on HDL cholesterol and DBP emerged. WQS analyses revealed a major contribution of PFNA and PFHxS for the cholesterol levels, although PFOA reported the highest concentration. PFOA and PFOS emerged as chemicals of concern regarding the association with SBP., Conclusions: The results showed a clear association between serum PFAS levels and markers of cardiovascular risk and support the importance of clinical surveillance of cardiovascular risk factors in population with a high exposure to PFAS, especially in the occupational setting., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Humans are exposed to several per- and polyfluoroalkyl substances (PFAS) daily; however, most previous studies have focused on individual PFAS. Although attention to effects of exposure to mixtures of PFAS has grown in recent years, there is no consensus on the appropriate statistical methods that can be used to assess their combined effect on human health., Objectives: We aim to perform a comprehensive review of the statistical methods used in the existing studies which evaluate the association between exposure to mixtures of PFAS and any adverse human health effect., Methods: The online databases PubMed, Embase and Scopus were searched for eligible studies, published during the last ten years (last search performed on April 08, 2021). Covidence software was used by two different reviewers to perform a title/abstract screening, followed by a full text revision of the selected papers., Results: A total of 3640 papers were identified, and after the screening process, 53 papers were included in the current review. Most of the studies were published between 2019 and 2021 and were conducted mainly in North America and Europe; more than half of the studies (28 out of 53) were conducted on mother and child pairs. WQS (Weighted Quantile Sum) Regression and BKMR (Bayesian Kernel Machine Regression) were used in 36 out of 53 papers to model mixtures' effects. Health outcomes included in the studies are immunotoxicity (n = 8), fetal development (n = 7), neurodevelopment (n = 9), reproductive hormones (n = 6), thyroid hormones (n = 7), outcomes related to metabolic pathways (n = 16)., Conclusion: Studies on human exposure to PFAS as complex mixtures and health consequences have substantially increased in the last few years. Based on our findings, we propose that addressing risk from PFAS mixtures will likely require combinations of approaches and implementation of constantly evolving statistical methods. Specific guidelines and tools for quality assessment and publication of mixture observational studies are warranted., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Per- 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., Methods: A 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., Results: We 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., Conclusions: Overall 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., (Copyright © 2021. Published by Elsevier Inc.)