Maternal plasma concentrations of perfluoroalkyl and polyfluoroalkyl substances during pregnancy and anogenital distance in male infants

The Effect of Various Environmental Pollutants on the Reproductive Health in Children: A Brief Review of the Literature

PURPOSE OF REVIEW

Environmental pollutants in air, water, soil, and food are a significant concern due to their potential adverse effects on fetuses, newborns, babies, and children. These chemicals, which pass to fetuses and babies through trans-placental transfer, breast milk, infant formula, dermal transfer, and non-nutritive ingestion, can cause health problems during childhood. This review aims to discuss how exposure to various environmental pollutants in early life stages can disrupt reproductive health in children.

RECENT FINDINGS

Environmental pollutants can affect Leydig cell proliferation and differentiation, decreasing testosterone production throughout life. This may result in cryptorchidism, hypospadias, impaired semen parameters, and reduced fertility. Although many studies on female reproductive health cannot be interpreted to support causal relationships, exposure to pollutants during critical windows may subsequently induce female reproductive diseases, including early or delayed puberty, polycystic ovary syndrome, endometriosis, and cancers. There is growing evidence that fetal and early-life exposure to environmental pollutants could affect reproductive health in childhood. Although diet is thought to be the primary route by which humans are exposed to various pollutants, there are no adopted nutritional interventions to reduce the harmful effects of pollutants on children's health. Therefore, understanding the impact of environmental contaminants on various health outcomes may inform the design of future human nutritional studies.

Prenatal exposure to per- and polyfluoroalkyl substances and DNA methylation in the placenta: A prospective cohort study

Epidemiological studies regarding the relationship between per- and polyfluoroalkyl substances (PFAS) and DNA methylation were limited. We investigated the associations of maternal PFAS concentrations with placental DNA methylation and examined the mediating role of methylation changes between PFAS and infant development. We measured the concentrations of 11 PFAS in maternal plasma during early pregnancy and infant development at six months of age. We analyzed genome-wide DNA methylation in 16 placental samples using reduced representation bisulfite sequencing. Additionally, we measured DNA methylation levels using bisulfite amplicon sequencing in 345 mother-infant pairs for five candidate genes, including carbohydrate sulfotransferase 7 (CHST7), fibroblast growth factor 13 (FGF13), insulin receptor substrate 4 (IRS4), paired like homeobox 2Ap (PHOX2A), and plexin domain containing 1 (PLXDC1). We found that placental DNA methylation profiles related to PFOA mainly enriched in angiogenesis and neuronal signaling pathways. PFOA was associated with hypomethylation of IRS4 and PLXDC1, and PFNA was associated with PLXDC1 hypomethylation. There were positive associations of CHST7 methylation with PFTrDA and IRS4 methylation with PFDoA and PFTrDA. PLXDC1 hypomethylation mediated the association between PFOA and suspected developmental delay in infants. Future studies with larger sample sizes are warranted to confirm these findings.

Prenatal per- and polyfluoroalkyl substances exposure and gut microbiota of infants: A prospective cohort study

Prenatal exposure to per- and polyfluoroalkyl substances (PFASs) has been reported to be linked to a series of adverse health outcomes in mothers and their children. As the gut microbiota is a sensitive biomarker for assessing the toxicity of environmental contaminants, this study attempted to investigate whether prenatal PFASs exposure was associated with the gut microbiota of infants. Based on the Shanghai-Minhang Birth Cohort Study, this prospective cohort study included 69 mother-infant pairs. Fasting blood samples were collected from pregnant women for the PFASs assay. We collected fecal samples of infants at 1 year of age and analyzed the V3-V4 hypervariable region of the bacterial 16 S rRNA gene by high-throughput sequencing. Among the detected 11 PFASs, the concentration of perfluorooctanoic acid (22.19 ng/mL) was the highest, followed by perfluorooctane sulfonic acid (12.08 ng/mL). Compared with infants whose mothers' total PFASs concentrations during pregnancy were at the 40th percentile or lower (reference group), the species richness and diversity of microbiota were lower in infants prenatally exposed to a high level of PFASs (the sum of PFASs concentrations above the 60th percentile). Prenatal exposure to PFASs was associated with a higher proportion of Acidaminococcaceae, Acidaminococcus, Megamonas, Megasphaera micronuciformis and Megamonas funiformis in infants. The changes of the species have been suggested to be associated with immune and metabolic dysfunction in humans. Functional alterations of gut microbiota due to PFASs exposure were dominated by an enrichment of butanoate metabolism. Our preliminary findings may shed light on the potential role of the microbiota underlying the well-known impact of prenatal PFASs exposure on health outcomes of humans in later life.

Determinants of organophosphate esters exposure in pregnant women from East China

Organophosphate esters (OPEs) have been broadly used in various industrial and consumer products, resulting in global distribution and human exposure. Gestational exposure to OPEs may adversely affect the health of both pregnant women and their offspring. To better understand OPE exposure in pregnant women, our study determined eight urinary metabolites of major OPEs in pregnant women (n = 733) recruited at 12-16 weeks of gestation from Shanghai, China, and explored the determinants of OPE exposure among various sociodemographic characteristics, lifestyles, and dietary factors. Urinary metabolites of OPEs, including bis (1,3-dichloro-2-propyl) phosphate (BDCPP), bis (2-chloroethyl) phosphate (BCEP), bis (1-chloro-2-propyl) phosphate (BCIPP), dicresyl phosphate (DCP), diphenyl phosphate (DPP), dibutyl phosphate (DBP), bis (2-ethylhexyl) phosphate (BEHP), and bis (2-butoxyethyl) phosphate (BBOEP), exhibited a detection rate ranging from 69.30% to 99.32%. Multivariate linear regression models indicated that pregnant women who were multiparous, had a higher family income per capita, worked in white-collar jobs, and took nutritional supplements such as milk powder and fish oil tended to have higher urinary OPE metabolite concentrations. Besides, independent of sociodemographic characteristics and lifestyle factors, consumption of more aquatic products, soy products, pork, and puffed food, as well as drinking of purified tap water versus tap water, were associated with increased urinary OPEs metabolite concentrations. Our study demonstrated that OPE exposure was ubiquitous in pregnant women from Shanghai, and provided new insights into the potential factors influencing OPE exposure during pregnancy.

Associations of Exposure to Air Pollution during the Male Programming Window and Mini-Puberty with Anogenital Distance and Penile Width at Birth and at 1 Year of Age in the Multicenter U.S. TIDES Cohort

BACKGROUND

Ambient air pollution may be a developmental endocrine disruptor. In animal models, gestational and perinatal exposure to diesel exhaust and concentrated particulate matter alters anogenital distance (AGD), a marker of prenatal androgen activity, in both sexes. Little is known in humans.

OBJECTIVES

We examined exposure to fine particulate matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) in relation to human AGD at birth and at 1 year of age, focusing on exposures during critical windows of reproductive development: the male programming window (MPW; gestational weeks 8-14) and mini-puberty (postnatal months 1-3).

METHODS

The Infant Development and Environment Study (TIDES) recruited first trimester pregnant women (n = 687 ) at four U.S. sites (Minneapolis, Minnesota; Rochester, New York; San Francisco, California; and Seattle, Washington) from 2010 to 2012. We measured anus to clitoris (AGD-AC) and anus to fourchette (AGD-AF) in female infants at birth; in males, we measured anus to penis (AGD-AP), anus to scrotum (AGD-AS), and penile width at birth and at 1 year of age. Using advanced spatiotemporal models, we estimated maternal exposure to PM 2.5 and NO 2 in the MPW and mini-puberty. Covariate-adjusted, sex-stratified linear regression models examined associations between PM 2.5 and NO 2 and AGD.

RESULTS

In males, a 1 - μ g / m 3 increase in PM 2.5 exposure during the MPW was associated with shorter AGD at birth, but a longer AGD at 1 year of age (e.g., birth AGD-AP: β = - 0.35 mm ; 95% CI: - 0.62 , - 0.07 ; AGD-AS: β = 0.37 mm ; 95% CI: 0.02, 0.73). Mini-pubertal PM 2.5 exposure was also associated with shorter male AGD-AP (β = - 0.50 mm ; 95% CI: - 0.89 , - 0.11 ) at 1 year of age. Although not associated with male AGD measures, 1 -ppb increases in NO 2 exposure during the MPW (β = - 0.07 mm ; 95% CI: - 0.02 , - 0.12 ) and mini-puberty (β = - 0.04 mm ; 95% CI: - 0.08 , 0.01) were both associated with smaller penile width at 1 year of age. Results were similar in multipollutant models, where we also observed that in females AGD-AC was inversely associated with PM 2.5 exposure, but positively associated with NO 2 exposure.

DISCUSSION

PM 2.5 and NO 2 exposures during critical pre- and postnatal windows may disrupt reproductive development. More work is needed to confirm these novel results and clarify mechanisms. https://doi.org/10.1289/EHP12627.

Impact of per- and polyfluorinated alkyl substances (PFAS) on the marine environment: Raising awareness, challenges, legislation, and mitigation approaches under the One Health concept

Per- and polyfluorinated alkyl substances (PFAS) have long been known for their detrimental effects on the ecosystems and living organisms; however the long-term impact on the marine environment is still insufficiently recognized. Based on PFAS persistence and bioaccumulation in the complex marine food network, adverse effects will be exacerbated by global processes such as climate change and synergies with other pollutants, like microplastics. The range of fluorochemicals currently included in the PFAS umbrella has significantly expanded due to the updated OECD definition, raising new concerns about their poorly understood dynamics and negative effects on the ocean wildlife and human health. Mitigation challenges and approaches, including biodegradation and currently studied materials for PFAS environmental removal are proposed here, highlighting the importance of ongoing monitoring and bridging research gaps. The PFAS EU regulations, good practices and legal frameworks are discussed, with emphasis on recommendations for improving marine ecosystem management.

Environmental exposure to per- and perfluoroalkyl substances in early pregnancy and newborn anogenital distance: A prospective cohort study

Per- and polyfluoroalkyl substances (PFAS) are persistent, ubiquitous pollutants, and the current epidemiological evidence regarding the impact of in utero exposure to PFAS on anogenital distance (AGD) is limited and inconclusive. The primary aim of this study was to investigate the potential associations between maternal exposure to PFAS during pregnancy and AGD in newborns. A total of 2273 mother-child pairs were recruited for this study, and both PFAS levels and AGD were measured. Multiple linear regression models were utilized to explore the relationships between individual PFAS and AGD. Additionally, quantile-based g-computation (QGC) was employed to assess the joint effects of mixtures of PFAS on AGD. Our findings showed that maternal exposure to PFOS (β = 0.518, 95% CI: 0.093, 0.942), PFNA (β = 0.487, 95% CI: 0.037, 0.937), PFDA (β = 0.443, 95% CI: 0.048, 0.838), PFUA (β = 0.434, 95% CI: 0.031, 0.838), and PFBS (β = 0.444, 95% CI: 0.124, 0.763) during early pregnancy had a significant positive association with AGD in boys. Similarly, in girls, maternal exposure to PFOS (β = 0.423, 95% CI: 0.006, 0.841), PFNA (β = 0.641, 95% CI: 0.207, 1.074), PFDA (β = 0.670, 95% CI: 0.306, 1.033), PFUA (β = 0.895, 95% CI: 0.509, 1.281), and PFBS (β = 0.474, 95% CI: 0.178, 0.770) had a positive association with AGD, while PFOA (β = -1.254, 95% CI: -1.786, -0.723) had a negative association. QGC models further confirmed that PFAS mixtures were positively associated with AGD. Moreover, PFBS was the primary contributor to the joint effects of PFAS mixtures on AGD. In summary, our study has provided further corroboration for the possibility that PFAS exposure can have an impact on AGD in both boys and girls. The use of AGD as a promising biomarker for endocrine disruption highlights the significance of our findings, which may have valuable clinical implications for reproductive diseases.

Endocrine disrupting compounds in the baby's world - A harmful environment to the health of babies

Globally, there has been a significant increase in awareness of the adverse effects of chemicals with known or suspected endocrine-acting properties on human health. Human exposure to endocrine disrupting compounds (EDCs) mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Although it is difficult to assess the full impact of human exposure to EDCs, it is well known that timing of exposure is of importance and therefore infants are more vulnerable to EDCs and are at greater risk compared to adults. In this regard, infant safety and assessment of associations between prenatal exposure to EDCs and growth during infancy and childhood has been received considerable attention in the last years. Hence, the purpose of this review is to provide a current update on the evidence from biomonitoring studies on the exposure of infants to EDCs and a comprehensive view of the uptake, the mechanisms of action and biotransformation in baby/human body. Analytical methods used and concentration levels of EDCs in different biological matrices (e.g., placenta, cord plasma, amniotic fluid, breast milk, urine, and blood of pregnant women) are also discussed. Finally, key issues and recommendations were provided to avoid hazardous exposure to these chemicals, taking into account family and lifestyle factors related to this exposure.

Water a major source of endocrine-disrupting chemicals: An overview on the occurrence, implications on human health and bioremediation strategies

Endocrine disrupting chemicals (EDCs) are toxic compounds that occur naturally or are the output of anthropogenic activities that negatively impact both humans and wildlife. A number of diseases are associated with these disruptors, including reproductive disorders, cardiovascular disorders, kidney disease, neurological disorders, autoimmune disorders, and cancer. Due to their integral role in pharmaceuticals and cosmetics, packaging companies, agro-industries, pesticides, and plasticizers, the scientific awareness on natural and artificial EDCs are increasing. As these xenobiotic compounds tend to bioaccumulate in body tissues and may also persist longer in the environment, the concentrations of these organic compounds may increase far from their original point of concentrations. Water remains as the major sources of how humans and animals are exposed to EDCs. However, these toxic compounds cannot be completely biodegraded nor bioremediated from the aqueous medium with conventional treatment strategies thereby requiring much more efficient strategies to combat EDC contamination. Recently, genetically engineered microorganism, genome editing, and the knowledge of protein and metabolic engineering has revolutionized the field of bioremediation thereby helping to breakdown EDCs effectively. This review shed lights on understanding the importance of aquatic mediums as a source of EDCs exposure. Furthermore, the review sheds light on the consequences of these EDCs on human health as well as highlights the importance of different remediation and bioremediation approaches. Particular attention is paid to the recent trends and perspectives in order to attain sustainable approaches to the bioremediation of EDCs. Additionally, rigorous restrictions to preclude the discharge of estrogenic chemicals into the environment should be followed in efforts to combat EDC pollution.

Prenatal perfluoroalkyl substances exposure and maternal sex steroid hormones across pregnancy

BACKGROUND

Poly- and perfluoroalkyl substances (PFAS) are ubiquitous and persistent environmental contaminants that may act as endocrine disruptors in utero, but the specific endocrine pathways are unknown.

OBJECTIVE

We examined associations between maternal serum PFAS and sex steroid hormones at three time points during pregnancy.

METHODS

Pregnant women participating in the Understanding Pregnancy Signals and Infant Development (UPSIDE) study contributed biospecimens, questionnaire, and medical record data in each trimester (n = 285). PFAS (including perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA)) were analyzed in second-trimester serum samples by high-performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). Total testosterone [TT], free testosterone [fT], estrone [E1], estradiol [E2], and estriol [E3]) were measured by LC-MS/MS in serum samples from each trimester. Linear mixed models with random intercepts were used to examine associations between log-transformed PFAS concentrations and hormone levels, adjusting for covariates, and stratifying by fetal sex. Results are presented as the mean percentage difference (Δ%) in hormone levels per ln-unit increase in PFAS concentration.

RESULTS

In adjusted models, PFHxS was associated with higher TT (%Δ = 20.0, 95%CI: 1.7, 41.6), particularly among women carrying male fetuses (%Δ = 15.3, 95%CI: 1.2, 30.7); this association strengthened as the pregnancy progressed. PFNA (%Δ = 7.9, 95%CI: 3.4, 12.5) and PFDA (%Δ = 7.2, 95%CI: 4.9, 9.7) were associated with higher fT, with associations again observed only in women carrying male fetuses. PFHxS was associated with higher levels of E2 and E3 in women carrying female fetuses (%Δ = 13.2, 95%CI: 0.5, 29.1; %Δ = 17.9, 95%CI: 3.2, 34.8, respectively). No associations were observed for PFOS and PFOA.

CONCLUSION

PFHxS, PFNA, and PFDA may disrupt androgenic and estrogenic pathways in pregnancy in a sex-dependent manner.

Associations between maternal urinary isoflavone concentrations and anogenital distance of offspring throughout infancy: a prospective cohort study

STUDY QUESTION

Are maternal urinary isoflavone (ISO) concentrations during pregnancy associated with anogenital distance (AGD) in infants at birth, and at 6 and 12 months of age?

SUMMARY ANSWER

Higher maternal urinary ISO concentrations during pregnancy were associated with longer AGD in infants of both sexes, and equol (EQU) and daidzein (DAD) were identified as the important ISO mixture components in the observed associations.

WHAT IS KNOWN ALREADY

Evidence of the association of prenatal exposure to ISO with offspring's AGD is mainly derived from animal studies, which used different study designs and had inconsistent results. Only one human study has been reported and it found null associations between maternal ISO exposure during pregnancy and AGD among boys at birth, with a small sample size and a wide range of exposure windows. No human study on girls was found.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study (Shanghai-Minhang Birth Cohort Study), with pregnant women recruited at 12-16 weeks of gestation in Shanghai, China between April and December 2012. One thousand two hundred and twenty-five live singletons were left in the cohort at delivery of which 480 mother-infant pairs had data on both maternal urinary ISO concentrations and at least one AGD measurement and were included in the present study. Anopenile distance (AGDAP) and anoscrotal distance (AGDAS) of boys and anoclitoral distance (AGDAC) and anofourchette distance (AGDAF) of girls were measured at birth and at 6 and 12 months of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Multiple linear regression models were used to examine the associations between maternal ISO concentrations and AGD. Bayesian kernel machine regression (BKMR) was implemented to examine both the overall effects of ISO mixture and the single effect of each ISO and identify important components of ISO mixture.

MAIN RESULTS AND THE ROLE OF CHANCE

A general profile of higher concentrations of maternal ISO associated with longer AGD in infants of both sexes was observed, when maternal education, parity, BMI before pregnancy (BMI, categorical variable), passive smoking during early pregnancy, age at delivery, gestational weeks and infant body size were adjusted for. Among boys, EQU was associated with increased AGDAS at birth and at 6 and 12 months, and DAD was associated with increased AGDAP at birth. Among girls, the associations of EQU and DAD with increased AGDAC and AGDAF at birth were found. When gestational weight gain and feeding patterns of infants in the first 6 months were additionally adjusted for, and maternal BMI was adjusted for as a continuous variable, more pronounced associations were observed, especially for associations of genistein (GEN), DAD and glycitein (GLY) with increased AGDAP and AGDAS at 6 months in boys. However, these associations were not always observed in the highest tertile group, and no consistent dose-response relationships were found. Similar results were observed in BKMR models, showing positive correlations of concentration of ISO mixture with increased AGDAS at both 6 and 12 months among boys, and increased AGDAC and AGDAF at birth among girls. Statistically significant increments of 4.96 mm (95% credible interval (CrI): 1.40, 8.52) and 1.07 mm (95% CrI: 0.02, 2.13) in AGDAS at 6 months among boys and AGDAC at birth among girls, respectively, were observed at the 75th percentile of ISO mixture, compared with 25th percentile. EQU and DAD were identified as the important components among ISO-AGD associations.

LIMITATIONS, REASONS FOR CAUTION

First, due to the short half-lives of ISO, the accuracy of a single spot urine sample reflecting ISO exposure during pregnancy may be limited, and thus may cause non-differential misclassification. Second, despite the adjustments for several important covariates in the study, unmeasured and residual confounding factors may remain a concern. Third, false discovery due to multiple testing may remain. Finally, the reduced sample sizes attributed to the loss of follow-up and missing data of confounders may limit our ability to detect an association, if any existed.

WIDER IMPLICATIONS OF THE FINDINGS

Prenatal ISO exposure may affect the reproductive development of offspring. As ISO can be widely detected in pregnant women, especially in Eastern countries, more studies are warranted to provide evidence of the effects of prenatal ISO exposure on long-term reproductive outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the National Key Research and Development Program of China (2021YFC2701003), the National Natural Science Foundation of China (22076123), the Science and Technology Commission of Shanghai Municipality (21ZR1454700 and 20ZR1448000), the Shanghai Municipal Health Commission (20194Y0160) and Innovation-oriented Science and Technology Grant from NHC Key Laboratory of Reproduction Regulation (CX2022-04). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Prenatal exposure to organophosphate esters is associated with decreased anogenital distance in offspring

BACKGROUND

Evidence from in vitro and rodent studies suggests that organophosphate esters (OPEs) may disrupt sex steroid hormone homeostasis, but no human studies, to date, have examined the effects of in utero exposure to OPEs on offspring reproductive development.

OBJECTIVE

Anogenital distance (AGD) is a sensitive biomarker of fetal hormonal milieu and has been used to assess reproductive toxicity. We evaluated the longitudinal effects of prenatal exposure to OPEs on the AGD of offspring from birth to 4 years.

METHODS

Based on Shanghai-Minhang Birth Cohort Study, pregnant women provided urine samples at a gestational age of 12-16 weeks, which were analyzed for eight OPE metabolites. AGD was measured in offspring at birth and 0.5, 1, and 4 years of age. We used generalized estimating equations (GEE) and Bayesian kernel machine regression (BKMR) models to estimate the associations of prenatal exposure to individual OPE metabolites and OPE mixtures with AGD stratified by sex.

RESULTS

A total of 733 mother-infant pairs were analyzed. Prenatal exposure to diphenyl phosphate and bis-(2-ethylhexyl) phosphate was associated with decreased AGD in boys in GEE models. Bis-(1-chloro-2-propyl) phosphate (BCIPP) showed a similar but marginally significant effect. Prenatal exposure to most OPE metabolites was associated with decreased AGD in girls, with the most profound association observed for bis (2-butoxyethyl) phosphate (BBOEP) and alkyl-OPEs. The OPE mixture was also inversely associated with AGD in both sexes. The single-exposure effects of BKMR models were largely consistent with those observed in the GEE models. In addition, alkyl-OPEs, particularly BBOEP, contributed the most to the decreased AGD in girls, while BCIPP contributed the most to the decreased AGD in boys.

CONCLUSIONS

This study provides the first human evidence that prenatal exposure to OPEs is associated with decreased AGD in offspring. The magnitude of these effects may vary depending on the structure of OPEs.

Association between prenatal exposure to perfluoroalkyl substances and anogenital distance in female neonates

BACKGROUND

Perfluoroalkyl substances (PFASs) have been reported to exert reproductive toxicity. Anogenital distance (AGD) is a biomarker of intrauterine androgen exposure and an indicator of genital development. An animal study reported that female neonatal rats exposed to perfluorooctanoic acid or perfluorooctane sulfonate (PFOS) during postnatal days 1-5 exhibited a longer AGD, while epidemiological studies have shown inconsistent results. This study aimed to examine the effects of prenatal exposure to PFASs on the AGD in female neonates.

METHODS

PFAS levels were measured in plasma samples obtained from pregnant women at 12-16 gestational weeks using high-performance liquid chromatography/mass spectrometry. The AGD of each female neonate was measured within 3 days after delivery. The anogenital index (AGI), calculated as AGD divided by weight, was also determined. A total of 362 motherinfant pairs were included in this study. A multivariate linear regression model was used to examine the association between prenatal ln-transformed concentrations of PFASs and AGD/AGI. In addition, weighted quantile sum regression (WQSR) and Bayesian kernel machine regression (BKMR) models were used to assess the overall effects of a mixture of PFASs on the AGD/AGI and to identify important contributors to the overall effect.

RESULTS

There was a consistent pattern of association between maternal PFAS concentrations and increased AGDanus to posterior fourchette (AF), AGDanus to clitoris (AC), and AGIAF lengths at birth. Statistical significance was found between maternal ln-transformed concentrations of perfluorohexane sulfonate (PFHxS), perfluorododecanoic acid, and perfluorotridecanoic acid and AGDAF, with β values (95% confidence interval [CI]) of 0.83 (0.16, 1.51), 0.32 (0.05, 0.59), and 0.25 (0.00, 0.51) mm, respectively; between PFOS and AGDAC, with a β value (95% CI) of 0.63 (0.04, 1.21) mm; and between PFHxS and AGIAF, with a β value (95% CI) of 0.22 (0.02, 0.43) mm/kg. Similarly, the WQSR and BKMR models showed that an increase in the AGDAF/AGIAF at birth was associated with co-exposure to a mixture of PFASs.

CONCLUSION

High maternal concentrations of PFASs were associated with increased AGD in female neonates, indicating that PFASs may impair reproductive development in female offspring in early life.

An experimental evaluation of the efficacy of perinatal sulforaphane supplementation to decrease the incidence and severity of vinclozolin-induced hypospadias in the mouse model

Determining the mechanisms of toxicity induced by pollutants has long been a research priority in lieu of considering the mechanisms of resilience that prevent deleterious impacts. Protective mechanisms in many taxa can be therapeutically targeted to enhance resilience to synthetic toxicants. For example, the environmental sensor, Nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2 or Nrf2), a transcription factor, facilitates transcription of many protective genes. Hypospadias is a common malformation of the penis. The risk of being born with hypospadias increases with pollutant exposure. We use vinclozolin-induced hypospadias in the mouse as a model to test the hypothesis that pollutant-induced birth defects can be prevented and reduced in severity by augmenting natural mechanisms of resilience. Pregnant mice were exposed to the demasculinizing toxicant, vinclozolin, in combination with increasing doses of the NRF2 activator, sulforaphane. The sulforaphane dose that most effectively increased masculinization (anogenital distance) was identified and used to test the hypothesis that sulforaphane reduces the hypospadias-inducing potency of vinclozolin. Finally, a Nrf2 knockout study was conducted to test whether NRF2 was required for the sulforaphane-induced rescue effects. Sulforaphane supplementation to vinclozolin exposed embryos increased anogenital distance in a nonlinear fashion typical of Nrf2 activators. The most effective dose of sulforaphane (45 mg/kg) reduced the occurrence and severity of vinclozolin-induced hypospadias and corrected penis morphogenesis. The sulforaphane-induced rescue effect was dependent on the presence of Nrf2. Nrf2 plays a critical role in protecting the fetus from vinclozolin and reduces the incidence and severity of hypospadias, the most common birth defect in boys in many countries. This work lays a foundation for developing prenatal supplements that will protect the fetus from pollutant-induced hypospadias. Studying the protective mechanisms that drive resilience to toxicants will facilitate innovation of protective therapies.

New insights on the effects of endocrine-disrupting chemicals on children

OBJECTIVE

Endocrine disrupting chemicals (EDCs) are present in many areas and materials of the common life, and exposure to these chemicals can occur from products to personal care, from air and food. This review aims to summarize the more recent epidemiological findings for the impact of EDCs on endocrine system health in children, including effects in growth, metabolism, sexual development, and reproduction.

SOURCES

The MEDLINE database (PubMed) was searched on August 24th, 2021, filtering for EDCs, endocrine disruptors, children, and humans.

SUMMARY OF THE FINDINGS

Intrauterine exposure of EDCs can have transgenerational effects, thus laying the foundation for disease in later life. The dose-response relationship may not always be predictable as even low-level exposures that may occur in everyday life can have significant effects on a susceptible individual. Although individual compounds have been studied in detail, the effects of a combination of these chemicals are yet to be studied to understand the real-life situation where human beings are exposed to a "cocktail effect" of these EDCs. Epidemiological studies in humans suggest EDCs' effects on prenatal growth, thyroid function, glucose metabolism, obesity, puberty, and fertility mainly through epigenetic mechanisms.

CONCLUSIONS

EDCs cause adverse effects in animals, and their effects on human health are now known and irrefutable. Because people are typically exposed to multiple endocrine disruptors, assessing public health effects is difficult. Legislation to ban EDCs and protect especially pregnant women and young children is required and needs to be revised and adjusted to new developments on a regular basis.

Association of exposure to prenatal perfluoroalkyl substances and estrogen receptor 1 polymorphisms with the second to fourth digit ratio in school-aged children: The Hokkaido study

Per- and Polyfluoroalkyl substances (PFAS) have endocrine-disrupting effects. The ratio of the lengths of the second and fourth digits (2D:4D) is a noninvasive retrospective index of prenatal exposure to sex hormones, and estrogen receptor 1 (ESR1) polymorphisms may contribute to 2D:4D determination. We investigated whether ESR1 polymorphisms modify the effects of prenatal PFAS exposure on 2D:4D. Participants (n = 1024) with complete data in a prospective birth cohort study (the Hokkaido Study) were included, and maternal plasma in the third trimester was used to examine PFAS concentrations. 2D:4D was determined from photocopies of palms of children using Vernier calipers. ESR1 polymorphisms (rs2234693, rs9340799, and rs2077647) were genotyped by TaqMan polymerase chain reaction. PFAS and 2D:4D association with ESR1 polymorphisms was assessed by multiple linear regression adjusted for potential confounding factors. A 10-fold increase in maternal perfluorooctanoic acid (PFOA) concentration was associated with a 1.54% [95% confidence interval (CI): 0.40, 2.68] increase in mean 2D:4D in children with an AA genotype at rs9340799 and a 2.24% (95% CI: 0.57, 3.92) increase in children with an AA genotype at rs2077647. A 10-fold increase in perfluorododecanoic acid (PFDoDA) was associated with a significant increase in 2D:4D in children with the AA genotype [rs9340799, 1.18% (95% CI: 0.02, 2.34); and rs2077647, 1.67% (95% CI: 0.05, 3.28)]. These associations were apparent among males. A significant gene-environment interaction between PFOA or PFDoDA and ESR1 polymorphism was detected. These findings suggest that ESR1 polymorphisms modify the effects of prenatal exposure to PFAS on sex differentiation.

Prenatal exposure to residential PM2.5 and its chemical constituents and weight in preschool children: A longitudinal study from Shanghai, China

BACKGROUND

Studies have reported that prenatal exposure to fine particulate matter (PM_2.5) might be associated with adverse birth outcomes in offspring. However, evidence with regard to the effects of prenatal exposure to PM_2.5 and, especially, its main chemical constituents on offspring's weight in childhood is limited and inconsistent.

OBJECTIVES

The present study aimed to examine associations of prenatal exposure to PM_2.5 total mass and its chemical constituents in each trimester with children's weight from birth to 6 years of age using data from Shanghai-Minhang Birth Cohort Study.

METHODS

A total of 1,084 mother-infant pairs were included with both PM_2.5 exposure data and at least one measurement of weight and height. Weight-for-Length (WLZ), BMI-for-Age (BMIz), and Weight-for-Age (WAZ) z-scores were generated according to the World Health Organization guidelines. Exposure to PM_2.5 total mass and its chemical constituents [organic carbon (OC), black carbon (BC), ammonium (NH₄⁺), nitrate (NO₃^-), sulfate (SO₄^2-), and soil dust (SOIL)] during pregnancy was estimated from a satellite based modelling framework. We used multiple informant model to estimate the associations of trimester-specific PM_2.5 total mass and its specific constituents concentrations with WLZ/BMIz and WAZ of offspring at birth and 1, 4, and 6 years of age.

RESULTS

In multiple informant model, we observed consistent patterns of associations between exposure to PM_2.5 total mass, OC, BC, NH₄⁺, NO₃^-, and SO₄^2- during the 2^nd and 3^rd trimesters and decreased WLZ/BMIz and WAZ at 1, 4, and 6 years of age in boys. We observed associations between prenatal exposure to PM_2.5 total mass, NH₄⁺, and NO₃^- during the 1^st and 2^nd trimesters and increased WLZ/BMIz and WAZ in girls at birth. However, there were null associations at 1 and 4 years of age and inverse associations at 6 years of age.

CONCLUSIONS

Prenatal exposure to PM_2.5 total mass and its main chemical constituents was associated with decreased weight in boys from 1 to 6 years of age, with increased weight at birth and decreased weight at 6 years of age in girls. Our findings suggest that prenatal exposure to PM_2.5 and its chemical constituents may have a lasting effect on offspring's weight in childhood.

Reproductive Hormone Concentrations and Associated Anatomical Responses: Does Soy Formula Affect Minipuberty in Boys?

CONTEXT

Soy formula feeding is common in infancy and is a source of high exposure to phytoestrogens, documented to influence vaginal cytology in female infants. Its influence on minipuberty in males has not been established.

OBJECTIVE

To assess the association between infant feeding practice and longitudinally measured reproductive hormones and hormone-responsive tissues in infant boys.

METHODS

The Infant Feeding and Early Development study was a prospective cohort of maternal-infant dyads requiring exclusive soy formula, cow milk formula, or breast milk feeding during study follow-up. In the 147 infant boy participants, serum testosterone, luteinizing hormone, stretched penile length, anogenital distance, and testis volume were longitudinally assessed from birth to 28 weeks. We examined feeding-group differences in age trajectories for these outcomes using mixed-effects regression splines.

RESULTS

Median serum testosterone was at pubertal levels at 2 weeks (176 ng/dL [quartiles: 124, 232]) and remained in this range until 12 weeks in all feeding groups. We did not observe differences in trajectories of hormone concentrations or anatomical measures between boys fed soy formula (n = 55) and boys fed cow milk formula (n = 54). Compared with breastfed boys (n = 38), soy formula-fed boys had a more rapid increase in penile length (P = .004) and slower initial lengthening of anogenital distance (P = .03), but no differences in hormone trajectories.

CONCLUSION

Reproductive hormone concentrations and anatomical responses followed similar trajectories in soy and cow milk formula-fed infant boys. Our findings suggest that these measures of early male reproductive development do not respond to phytoestrogen exposure during infancy.

Maternal exposure to perfluoroalkyl chemicals and anogenital distance in the offspring: A Faroese cohort study

Exposure to perfluoroalkyl substances (PFASs) has in some studies been associated with reduced anogenital distance (AGD) in newborns as a sensitive indicator of prenatal anti-androgenic exposure. The aim of this study was to investigate the association between maternal PFAS exposure and offspring AGD in a population with wide ranges of PFAS exposures. Participants were recruited in the Faroe Islands in 2007-2009, and information on AGD and PFAS exposure was obtained from 463 mother-infant pairs. Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured in maternal serum. Data were analyzed using multiple linear regression analysis adjusted for birth weight, child age at examination, parity, and maternal education level. Among boys, higher maternal serum concentrations of PFOA, PFOS, PFNA and PFDA were significantly associated with a longer AGD, both with the exposure entered as a continuous variable and as quartiles. Boys in the highest quartile of PFOA, PFOS, PFNA and PFDA exposure had an increase in AGD of 1.2 mm (95 % CI 0.1;2.2), 1.3 mm (95 % CI 0.3;2.3), 1.0 mm (95 % CI 0.0:2.0) and 1.3 mm (95 % CI 0.3;2.4), respectively, when compared to boys in the lowest quartile of exposure (p < 0.05). No significant association was found between male AGD and PFHxS. No association was found for girls. In conclusion, elevated maternal exposure to major PFASs was significantly associated with a longer AGD in boys. No significant associations were found among girls, thus suggesting a sex-dimorphic effect of PFAS exposure.

Androgens and the masculinization programming window: human-rodent differences

Human male reproductive disorders are common and may have a fetal origin - the testicular dysgenesis syndrome (TDS) hypothesis. In rats, experimentally induced TDS disorders result from disruption of fetal androgen production/action specifically in the masculinization programming window (MPW). MPW androgen action also programs longer anogenital distance (AGD) in male versus female rats; shorter male AGD is correlated with risk and severity of induced TDS disorders. AGD thus provides a lifelong, calibrated readout of MPW androgen exposure and predicts likelihood of reproductive dysfunction. Pregnant rat exposure to environmental chemicals, notably certain phthalates (e.g. diethyl hexl phthalate, DEHP; dibutyl phthalate, DBP), pesticides or paracetamol, can reduce fetal testis testosterone and AGD and induce TDS disorders, provided exposure includes the MPW. In humans, AGD is longer in males than females and the presumptive MPW is 8-14 weeks' gestation. Some, but not all, epidemiological studies of maternal DEHP (or pesticides) exposure reported shorter AGD in sons, but this occurred at DEHP exposure levels several thousand-fold lower than are effective in rats. In fetal human testis culture/xenografts, DEHP/DBP do not reduce testosterone production, whereas therapeutic paracetamol exposure does. In humans, androgen production in the MPW is controlled differently (human chorionic gonadotrophin-driven) than in rats (paracrine controlled), and other organs (placenta, liver, adrenals) contribute to MPW androgens, essential for normal masculinization, via the 'backdoor pathway'. Consequently, early placental dysfunction, which is affected by maternal lifestyle and diet, and maternal painkiller use, may be more important than environmental chemical exposures in the origin of TDS in humans.

Perfluorotridecanoic acid inhibits fetal Leydig cell differentiation after in utero exposure in rats via increasing oxidative stress and autophagy

Perfluorotridecanoic acid (PFTrDA) is a long-chain perfluoroalkyl substance, and its effect on the differentiation of fetal Leydig cells remains unclear. The objective of this study is to explore the effect of in utero PFTrDA exposure on the differentiation of fetal Leydig cells and investigate its underlying mechanisms. Pregnant Sprague-Dawley female rats were daily administered by gavage of PFTrDA at doses of 0, 1, 5, and 10 mg/kg from gestational day 14 to 21. PFTrDA had no effect on the body weight of dams, but significantly reduced the body weight and anogenital distance of male pups at birth at a dose of 10 mg/kg. PFTrDA significantly decreased serum testosterone levels as low as 1 mg/kg. PFTrDA did not affect fetal Leydig cell number, but promoted abnormal aggregation of fetal Leydig cells at doses of 5 and 10 mg/kg. PFTrDA down-regulated the expression of Insl3, Lhcgr, Scarb1, Star, Hsd3b1, Cyp17a1, Nr5a1, and Dhh as well as their proteins. PFTrDA lowered the levels of antioxidants (SOD1, CAT, and GPX1), induced autophagy as shown by increased levels of LC3II and beclin1, and reduced the phosphorylation of mTOR. In conclusion, PFTrDA inhibits the differentiation of fetal Leydig cells in male pups after in utero exposure mainly through increasing oxidative stress and inducing autophagy.

Association between prenatal exposure to polybrominated diphenyl ethers and anogenital distance in girls at ages 0-4 years

Anogenital distance (AGD) is a sensitive marker for the effect of in utero hormonal disturbance. However, studies on the associations between prenatal exposure to polybrominated diphenyl ethers (PBDEs), a group of endocrine disruptors, and AGD are limited. We examined the associations between prenatal PBDE exposure and AGD in girls at ages 0-4 years in the Shanghai-Minhang Birth Cohort Study. We measured PBDE in cord plasma collected from 148 girls at birth. Of them, two AGD metrics (AGD_AC: from the anterior surface of the clitoral hood to the center of the anus; AGD_AF: from the posterior end of the fourchette to the center of the anus) were measured in 142, 114, 104 and 120 of girls at birth, 6, 12, and 48 months of age, respectively. Linear regression models and linear mixed models were used to evaluate the associations between PBDE exposure and AGD at ages 0-4 years. We found positive associations of PBDE exposure with AGD_AF and AGD_AC in linear regression models, although some associations only reached significance at 6 and 48 months of age. For AGD_AF, the associations were statistically significant for BDE-47, -99, and -100 at 6 months of age (β = 2.34, 95% CI (0.21, 4.48) for BDE-47; β = 2.21, 95% CI (0.05, 4.36) for BDE-99; β = 2.12, 95% CI (0.01, 4.23) for BDE-100), and for BDE-99 and -100 at 48 months of age (β = 4.49, 95% CI (1.27, 7.71) for BDE-99; β = 5.04, 95% CI (1.87, 8.22) for BDE-100), while statistically significant associations with AGD_AC were only observed for BDE-99, -100, -153, and ∑₅PBDEs at 48 months of age (β = 7.62, 95% CI (2.59, 12.64) for BDE-99; β = 7.04, 95% CI (2.01, 12.07) for BDE-100; β = 5.41, 95% CI (0.45, 10.38) for BDE-153; β = 5.05 mm, 95% CI (0.09, 10.01 for ∑₅PBDEs). A consistent pattern of positive associations between prenatal exposure to PBDEs and AGD was also observed in linear mixed models. The finding provided further insights into the adverse effects of PBDEs on reproductive development at low dose exposure.

Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men

Male reproductive health has declined as indicated by increasing rates of cryptorchidism, i.e., undescended testis, poor semen quality, low serum testosterone level, and testicular cancer. Exposure to endocrine disrupting chemicals (EDCs) has been proposed to have a role in this finding. In utero exposure to antiandrogenic EDCs, particularly at a sensitive period of fetal testicular development, the so-called 'masculinization programming window (MPW)', can disturb testicular development and function. Low androgen effect during the MPW can cause both short- and long-term reproductive disorders. A concurrent exposure to EDCs may also affect testicular function or damage testicular cells. Evidence from animal studies supports the role of endocrine disrupting chemicals in development of male reproductive disorders. However, evidence from epidemiological studies is relatively mixed. In this article, we review the current literature that evaluated relationship between prenatal EDC exposures and anogenital distance, cryptorchidism, and congenital penile abnormality called hypospadias. We review also studies on the association between early life and postnatal EDC exposure and semen quality, hypothalamic-pituitary-gonadal axis hormone levels and testicular cancer.

Prenatal exposure to perfluoroalkyl substances and cord plasma lipid concentrations

The effect of prenatal exposure to perfluoroalkyl substances (PFAS) on lipid concentrations in newborns is unknown. Using data from the Shanghai-Minhang Birth Cohort Study, we prospectively assessed the health effects of prenatal exposure to individual and multiple PFAS on cord lipid concentrations. Maternal plasma samples collected at 12-16 weeks of gestation were analyzed for eleven PFAS, and cord blood samples were analyzed for lipids: total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). We used multiple linear regression models to evaluate the associations of each individual PFAS with each lipid parameter, and used Bayesian Kernel Machine Regression (BKMR) models to assess the overall and single-exposure effects of eight PFAS with the detection rate above 80% on cord lipid concentrations. In multiple linear regression models, for each unit increase in ln-transformed maternal concentrations of perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), and perfluorotridecanoic acid (PFTrDA), ln-transformed TC concentration decreased by 0.15 mg/dL (95% confidence interval (CI): -0.25, -0.05), 0.12 mg/dL (95% CI: -0.19, -0.05), 0.12 mg/dL (95% CI: -0.19, -0.05), and 0.05 mg/dL (95% CI: -0.09, -0.01), respectively, and ln-transformed HDL-C concentration decreased by 0.17 mg/dL (95% CI: -0.29, -0.05), 0.12 mg/dL (95% CI: -0.20, -0.03), 0.12 mg/dL (95% CI: -0.20, -0.03), and 0.06 mg/dL (95% CI: -0.11, -0.00), respectively. Statistically significant inverse associations were also observed between ln-transformed concentrations of PFDA, PFUdA, or PFTrDA and ln-transformed cord concentrations of TG and LDL-C. In BKMR models, the mixture of eight PFAS showed suggestively inverse association with all ln-transformed lipid concentrations, such that ln-transformed TC concentration of exposure to the 75th percentile of the mixture was 0.11 units (95% credible interval, -0.21, -0.01) lower than the 25th percentile exposure. Our findings indicated that prenatal exposure to PFAS may disrupt lipid metabolism in newborns.

Prenatal exposure to perfluoroalkyl substances and thyroid hormone concentrations in cord plasma in a Chinese birth cohort

BACKGROUND

Evidence of associations between prenatal exposure to perfluoroalkyl substances (PFASs) and fetal thyroid hormones (THs) is controversial, and few studies have estimated the associations, while addressing the high correlations among multiple PFASs. We aimed to examine the associations between prenatal PFAS exposure and thyroid hormone concentrations in cord blood.

METHODS

A total of 300 mother-infant pairs from the Shanghai-Minhang Birth Cohort Study were included. We measured the concentrations of eight PFASs in maternal plasma samples collected at 12-16 gestational weeks, as well as those of total thyroxine (T4), free T4 (FT4), total triiodothyronine (T3), free T3 (FT3), and thyroid stimulating hormone (TSH) in cord plasma. We estimated the associations between maternal PFAS concentrations and TH concentrations using linear regression and Bayesian kernel machine regression (BKMR) models.

RESULTS

In BKMR models, higher PFAS mixture concentrations were associated with increased T3 concentrations, and there were suggestive associations with increased FT3 concentrations. For single-exposure effects in BKMR models, a change in PFDA, PFUdA, and PFOA concentrations from the 25th to 75th percentile was associated with a 0.04 (95%CrI: - 0.01, 0.09), 0.02 (95%CrI: - 0.03, 0.07), and 0.03 (95%CrI: - 0.001, 0.06) nmol/L increase in T3 concentrations, respectively. PFOA, PFNA, and PFDA were the predominant compounds in PFASs-FT3 associations, and the corresponding estimates were 0.11 (95% CrI: 0.02, 0.19), - 0.17 (95% CrI: - 0.28, - 0.07), and 0.12 (95% CrI: - 0.004, 0.24) pmol/L, respectively. A change in PFNA and PFOA concentrations from the 25th to 75th percentile was associated with a - 1.69 (95% CrI: - 2.98, - 0.41) μIU/mL decrease and a 1.51 (95% CrI: 0.48, 2.55) μIU/mL increase in TSH concentrations. The associations of PFOA and PFNA with T3/FT3 were more pronounced in boys, while those with TSH were more pronounced in girls.

CONCLUSION

Our results suggest that prenatal exposure to multiple PFASs was associated with thyroid hormones in cord blood. However, individual PFAS had varied effects-differing in magnitude and direction-on fetal thyroid hormones.

Prenatal exposure to residential PM2.5 and anogenital distance in infants at birth: A birth cohort study from Shanghai, China

Fine particulate matter (PM_2.5) is believed to be one of the most hazardous air pollution with a ubiquitous presence. Animal studies have reported the association between prenatal exposure to traffic pollutant (not exclusively including PM_2.5) and reproductive development in male offspring. However, the effects of prenatal exposure to PM_2.5 on reproductive health in children are still unknown. The present study was based on the Shanghai-Minhang Birth Cohort Study (S-MBCS). A total of 876 pregnant women and their infants were included. Infants' anogenital distance (AGD, the distance from the anus to the genitals; AGDap [anus-penis] and AGDas [anus-scrotum] for boys, and AGDac [anus-clitoris] and AGDaf [anus-fourchette] for girls) were measured at birth. PM_2.5 concentrations during pregnancy were estimated using satellite based modeling approach. Multiple linear regression analysis and multiple informant model were conducted to examine the associations between prenatal exposure to PM_2.5 (pre μg/m³) and offspring's AGDs (mm). In order to minimize the misclassification of exposure, a sensitivity analysis restricted to mothers being off work during pregnancy was performed. In multiple linear regression models, we found that prenatal exposure to PM_2.5 during the 1^st and 3^rd trimesters was associated with shorter AGDs. In multiple informant model, similar patterns were found, and statistically significant reductions were observed in AGDap (β=-0.278, 95%CI: -0.343∼-0.212), AGDac (β=-0.188, 95%CI: -0.247∼-0.130) and AGDaf (β= -0.163, 95%CI: -0.238∼-0.088) with PM_2.5 exposure during the 1^st trimester, and AGDap (β=-0.201, 95%CI: -0.247∼-0.155), AGDas (β=-0.158, 95%CI: -0.198∼-0.117), AGDac (β=-0.128, 95%CI: -0.167∼-0.089) and AGDaf (β = -0.144, 95%CI: -0.194∼-0.094) with PM_2.5 exposure during the 3^rd trimester. The sensitivity analysis restricted to women being off work during pregnancy showed similar results. PM_2.5 exposure during the 1^st and 3^rd trimesters was associated with shortened AGDs in offspring at birth. Our findings provide preliminary evidence that prenatal exposure to PM_2.5 might be associated with the reproductive development of offspring.

Incidence of ocular conditions associated with perfluoroalkyl substances exposure: Isomers of C8 Health Project in China

The detrimental effects of perfluoroalkyl substances (PFASs) on several physiological systems have been reported, but the association of PFASs with eye, one of the most sensitive and exposed organ, has never been explored. To investigate the association between eye diseases including visual impairment (VI) and PFASs isomers, a cross-sectional stratified study was conducted in 1202 Chinese population, aged 22-96 years, from Shenyang, China. A standard protocol including Snellen vision chart, slit-lamp microscopy and direct ophthalmoscopy was used to examine eye diseases/conditions relating to anterior and posterior segment of eyes. In addition, we measured the blood concentrations of 19 linear and branched PFASs at one-time point. Results indicated that blood levels of PFASs were significantly higher in eye disease group than normal group. PFASs exposure were positively associated with both combined eye diseases and individual eye diseases. Among other PFASs, linear perfluorooctane sulfonate (n-PFOS; odds ratio [OR] = 3.37, 95% confidence interval [CI]: 2.50, 4.56), branched perfluorooctane sulfonate (Br-PFOS; OR = 2.25, 95% CI: 1.72, 2.93) and linear perfluorooctanoic acid (n-PFOA; OR = 1.79, 95% CI: 1.36, 2.37) significantly increases the odds of VI. Vitreous disorder was adversely associated with long-chain PFASs exposure. For example, perfluorotridecanoic acid (PFTrDA; OR = 1.86, 95% CI: 1.51, 2.29) and perfluorodecanoic acid (PFDA; OR = 1.79, 95% CI: 1.36, 2.36) showed the most significant association. In conclusion, this study suggests higher serum PFASs levels were associated with increase odds of VI and vitreous disorder in Chinese adults.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Application of the Key Characteristics of Carcinogens to Per and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) constitute a large class of environmentally persistent chemicals used in industrial and consumer products. Human exposure to PFAS is extensive, and PFAS contamination has been reported in drinking water and food supplies as well as in the serum of nearly all people. The most well-studied member of the PFAS class, perfluorooctanoic acid (PFOA), induces tumors in animal bioassays and has been associated with elevated risk of cancer in human populations. GenX, one of the PFOA replacement chemicals, induces tumors in animal bioassays as well. Using the Key Characteristics of Carcinogens framework for cancer hazard identification, we considered the existing epidemiological, toxicological and mechanistic data for 26 different PFAS. We found strong evidence that multiple PFAS induce oxidative stress, are immunosuppressive, and modulate receptor-mediated effects. We also found suggestive evidence indicating that some PFAS can induce epigenetic alterations and influence cell proliferation. Experimental data indicate that PFAS are not genotoxic and generally do not undergo metabolic activation. Data are currently insufficient to assess whether any PFAS promote chronic inflammation, cellular immortalization or alter DNA repair. While more research is needed to address data gaps, evidence exists that several PFAS exhibit one or more of the key characteristics of carcinogens.