Associations among maternal perfluoroalkyl substance levels, fetal sex-hormone enzymatic gene polymorphisms, and fetal sex hormone levels in the Hokkaido study

Association of prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances with fetal growth trajectories

BACKGROUND

Maternal perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure during pregnancy is linked to adverse birth outcomes; however, its impact on fetal growth trajectories remains unclear.

OBJECTIVE

To examine the relationship between prenatal PFAS exposure and fetal growth trajectories.

METHODS

We included 352 mother-infant pairs from a prospective study conducted at Changsha Hospital for Maternal and Child Health Care, Hunan Province, China. Maternal blood samples at 11-13 weeks gestation were analyzed for 25 PFAS. Fetal growth indicators-estimated fetal weight (EFW), biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL)-were measured at 14-41 weeks of gestation and expressed as Z-scores using INTERGROWTH-21st standards. Linear mixed-effects models assessed associations between PFAS levels and growth trajectories, with subgroup analyses performed by infant sex.

RESULTS

Early pregnancy perfluorooctanoic acid (PFOA) concentration was negatively associated with EFW (β = -0.17, 95% confidence interval [CI]: -0.33, -0.01) Z-scores, perfluorodecanoic acid (PFDA) concentration was negatively associated with BPD (β = -0.13, 95% CI: -0.26, -0.002) and AC (β = -0.12 95% CI: -0.23, -0.004) Z-scores; perfluoroundecanoic acid (PFUdA) concentration was negatively associated with EFW (β = -0.14, 95% CI: -0.26, -0.02) and BPD (β = -0.18, 95% CI: -0.30, -0.06) Z-scores, perfluorooctane sulfonic acid (PFOS) concentration was negatively associated with AC (β = -0.13, 95% CI: -0.25, -0.01) Z-scores. In contrast, N-ethylperfluoro-1-octanesulfonamide (N-EtFOSA-M) concentration was positively associated with EFW (β = 0.11, 95% CI: 0.02, 0.19), BPD (β = 0.11, 95% CI: 0.02, 0.20) and FL (β = 0.13, 95% CI: 0.04, 0.22) Z-scores and potassium11-chloroeicosafluoro-3-oxaundecane-I-sulfonate (8:2CI-PFESA) concentration was positively associated with HC (β = 0.08, 95% CI: 0.004, 0.16) Z-scores. Subgroup analyses revealed that PFDA, PFUdA, and perfluorotridecanoic acid (PFTrDA) concentrations were negatively associated with EFW Z-scores in female infants, and 8:2CI-PFESA concentrations was positively associated with HC and FL Z-scores in male infants.

CONCLUSION

Legacy PFAS exposure may impede fetal growth, especially in female infants; whereas, novel PFAS may be positively associated with fetal growth, particularly in male infants.

Effects of Early-life PFAS Exposure on Child Neurodevelopment: A Review of the Evidence and Research gaps

PURPOSE OF REVIEW

Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals with many modern applications, leading to widespread contamination and universal human exposure. PFAS exposure during early life is of particular concern, given susceptibility of the developing fetal and infant brain to toxic exposures. This review aims to synthesize current evidence, discuss methodological challenges, and highlight research gaps to guide future studies on the impact of PFAS on neurodevelopment.

RECENT FINDINGS

Sixty-one studies in total were published from 2008 to March 2024, with 35 in the last five years. Findings primarily link early life PFAS exposure to reduced cognitive, motor, and language development in infancy and increased behavioral issues like hyperactivity in childhood. Large studies have shown mixed results concerning child cognition, executive function, autism, and ADHD, with some indicating no association or unexpected protective findings. Sex-specific associations have been observed, but not consistently. Most research has addressed low-level exposure, suggesting subtle but potentially significant population-wide neurodevelopmental effects. Recent research also highlights concerns about newer, alternative PFAS, suggesting they too might affect neurodevelopment.  The effects of early-life PFAS exposure on neurodevelopment merit further study, particularly the cumulative effects of prenatal and postnatal exposures. Research has not fully explored sensitive subgroups or potential mitigating factors such as breastfeeding and nutrient intake, which will require larger, more diverse samples. Future directions include deeper study of PFAS mixtures, interactions with other neurotoxic environmental chemicals, and effects of newer PFAS types. There is also a need to focus on neuropsychological functioning in later childhood, using direct assessments for more reliable evaluations.

Exposure to Synthetic Endocrine-Disrupting Chemicals in Relation to Maternal and Fetal Sex Steroid Hormones: A Scoping Review

PURPOSE OF REVIEW

Many synthetic endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment and highly detected among pregnant people. These chemicals may disrupt maternal and/or fetal sex steroid hormones, which are critical to pregnancy maintenance and fetal development. Here, we review the epidemiological literature examining prenatal exposure to common synthetic EDCs in relation to maternal and fetal sex steroid hormones.

RECENT FINDINGS

We performed a literature search using PubMed, SCOPUS, and Embase, ultimately identifying 29 articles for full review. Phenols, parabens, and persistent organic pollutants generally showed inverse associations with androgens, estrogens, and progesterone. Phthalates and per-and polyfluoroalkyl substances tended to be inversely associated with progesterone, while evidence regarding androgens and estrogens was mixed. Inconsistent, but noteworthy, differences by fetal sex and timing of exposure/outcome were observed. Overall, the literature suggests EDCs may disrupt maternal and fetal sex steroid activity, though findings are mixed. Given the pervasive, high-volume production of these synthetic chemicals and the critical functions sex steroid hormones play during gestation, additional research is warranted.

Association Between Prenatal Exposure to Per- and Poly-Fluoroalkyl Substances From Electronic Waste Disassembly Areas and Steroid Hormones in Human Milk Samples

Per- and poly-fluoroalkyl substances (PFAS), which are long-lasting environmental contaminants that are released into the environment during the e-waste disassembly process, pose a threat to human health. Human milk is a complex and dynamic mixture of endogenous and exogenous substances, including steroid hormones and PFAS. Therefore, in this study, we aimed to investigate the association between PFAS and steroid hormones in human milk from women living close to an e-waste disassembly area. In 2021, we collected milk samples from 150 mothers within 4 weeks of delivery and analyzed them via liquid chromatography-tandem mass spectrometry to determine the levels of 21 perfluorinated compounds and five steroid hormones (estrone, estriol, testosterone, progesterone, and androstenedione [A-dione]). We also performed multiple linear regression analysis to clarify the association between maternal PFAS exposure and steroid hormone concentrations. Our results indicated that PFOA and PFOS were positively associated with estrone (β, 0.23; 95% CI, 0.08-0.39) and A-dione (β, 0.186; 95% CI, 0.016-0.357) concentrations in human milk, respectively. Further, the average estimated daily intake of PFOA and PFOS were 36.5 ng/kg bw/day (range, 0.52-291.7 ng/kg bw/day) and 5.21 ng/kg bw/day (range, 0.26-32.3 ng/kg bw/day), respectively. Of concern, the PFAS intake of breastfeeding infants in the study area was higher than the recommended threshold. These findings suggested that prenatal exposure to PFAS from the e-waste disassembly process can influence steroid hormones levels in human milk. Increased efforts to mitigate mother and infant exposure to environmental pollutants are also required.

Associations of per- and polyfluoroalkyl substances with uterine leiomyomata incidence and growth: a prospective ultrasound study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are endocrine-disrupting chemicals used in commercial and consumer products.

OBJECTIVE

We evaluated PFAS exposure in relation to incidence and growth of uterine leiomyomata (UL), hormone-dependent neoplasms that are associated with severe gynecologic morbidity.

METHODS

We studied 1158 participants in the Study of Environment, Lifestyle, and Fibroids, a Detroit-based prospective cohort study of Black females aged 23-35 years at enrollment (2010-2012). At enrollment and four subsequent visits during 10 years of follow-up, participants attended in-person clinic visits, completed questionnaires, provided non-fasting blood samples, and underwent ultrasound for UL detection. We quantified 7 PFAS in baseline plasma samples using mass spectrometry. We used Cox regression and probit Bayesian kernel machine regression to estimate individual and joint effects of PFAS on UL incidence. We fit linear mixed models to estimate effects of individual PFAS on UL growth. We stratified by parity, an important route of PFAS elimination and determinant of UL.

RESULTS

In individual PFAS analyses, we observed inverse associations for perfluorodecanoate (PFDA; ≥0.3 vs. <0.2 ng/ml: hazard ratio [HR] = 0.74; 95% confidence interval [CI]: 0.54-1.00) and perfluoroundecanoate (detected vs. non-detected: HR = 0.78; 95% CI: 0.61-1.01) and a weak positive association for perfluorohexane sulfonate (≥1 vs. <0.6 ng/ml: HR = 1.17; 95% CI: 0.85-1.61), while perfluorooctane sulfonate, perfluorooctanoate, perfluorononanoate (PFNA), and 2-N-methyl-perfluorooctane sulfonamido acetate (MeFOSAA) showed little association with UL incidence. The PFAS mixture was inversely associated with UL incidence, a finding driven by MeFOSAA and PFDA; however, PFNA was positively associated with UL incidence. The inverse association for PFDA and positive association for PFNA were stronger among nulliparous participants. Most PFAS showed slight inverse associations with UL growth.

IMPACT STATEMENT

In this prospective ultrasound study of 1158 Black females aged 23-35 years at enrollment, we conducted a mixtures analysis to account for co-pollutant confounding and interaction. MeFOSAA and PFDA concentrations were inversely associated with UL incidence, while PFNA concentrations were positively associated with UL incidence. Concentrations of most PFAS were associated with decreased UL growth. This study contributes data to the sparse literature on PFAS exposure and UL development.

Associations of per- and polyfluoroalkyl substances with maternal early second trimester sex-steroid hormones

BACKGROUND/AIMS

Pregnant women are exposed to persistent environmental contaminants, including per- and polyfluoroalkyl substances (PFAS) that disrupt thyroid function. However, it is unclear if PFAS alter maternal sex-steroid hormone levels, which support pregnancy health and fetal development.

METHODS

In Illinois women with relatively high socioeconomic status (n = 460), we quantified perfluorononanoic (PFNA), perfluorooctane sulfonic (PFOS), perfluorooctanoic (PFOA), methyl-perfluorooctane sulfonamide acetic acid, perfluorohexanesulphonic (PFHxS), perfluorodecanoic (PFDeA), and perfluoroundecanoic (PFUdA) acid concentrations in fasting serum samples at median 17 weeks gestation, along with plasma progesterone, testosterone, and estradiol. We evaluated covariate-adjusted associations of ln-transformed hormones with each ln-transformed PFAS individually using linear regression and with the PFAS mixture using quantile-based g-computation (QGComp).

RESULTS

Interquartile range (IQR) increases in PFOS were associated with higher progesterone (%Δ 3.0; 95%CI: -0.6, 6.6) and estradiol (%Δ: 8.1; 95%CI: 2.2, 14.4) levels. Additionally, PFHxS was positively associated with testosterone (%Δ: 10.2; 95%CI: 4.0, 16.7), whereas both PFDeA and PFUdA were inversely associated with testosterone (%Δ: -5.7; 95%CI: -10.3, -0.8, and %Δ: -4.1; 95%CI: -7.6, -0.4, respectively). The IQR-standardized PFAS mixture was not associated with progesterone (%Δ: 1.6; 95%CI: -5.8, 9.2), due equal partial positive (%Δ: 9.2; driven by PFOA) and negative (%Δ: -7.4; driven by PFOS) mixture associations. Similarly, the mixture was not associated with testosterone (%Δ: 5.3; 95%CI: -9.0, 20.1), due to similar partial positive (%Δ: 23.6; driven by PFHxS) and negative (%Δ: -17.4; driven by PFDeA) mixture associations. However, we observed a slightly stronger partial positive (%Δ: 25.6; driven by PFOS and PFUdA) than negative (%Δ: -16.3; driven by PFOA) association resulting in an overall non-significant positive trend between the mixture and estradiol (%Δ: 8.5; 95%CI: -3.7, 20.9).

CONCLUSION

PFAS mixture modeled using QGComp was not associated with maternal sex-steroid hormones due to potential opposing effects of certain PFAS. Additional prospective studies could corroborate these findings.

Associations of prenatal exposure to per- and polyfluoroalkyl substances and fetal sex hormones in the Guangxi Zhuang Birth Cohort Study: Greater effect of long-chain PFAS

Fetal sex hormone homeostasis disruption could lead to reproductive and developmental abnormalities. However, previous studies have reported inconsistent findings regarding the association of maternal per- and polyfluoroalkyl substances (PFAS) exposure with fetal sex hormone levels. A total of 277 mother-infant pairs from the Guangxi Zhuang Birth Cohort Study between 2015 and 2019 were selected. We quantified nine PFAS in maternal serum in early pregnancy, and detected three sex hormones, namely, estradiol (E2), progesterone (P4) and testosterone (TT), in cord blood. The generalized linear model (GLM) and Bayesian kernel machine regression (BKMR) model were used for single- and multiple-exposure analyses, respectively. In the GLM, there was no significant association between an individual PFAS and any hormone level or the E2/TT ratio, but a negative association between perfluorododecanoic acid (PFDoA) exposure and P4 levels in female infants was observed after stratification by sex. In the BKMR, a mixture of nine PFAS was positively associated with E2 levels and the E2/TT ratio, with the same main contributors, i.e., perfluoroundecanoic acid (PFUnA). And PFAS mixtures were not associated with P4 or TT levels. After stratification by infant sex, positive associations of PFAS mixtures with E2 levels and the E2/TT ratio were observed only in male infants, with the same main contributors, i.e., PFUnA. There was a positive association between PFAS mixtures and P4 levels in male infants, in which PFUnA was the main contributor; but a reverse association between PFAS mixtures and P4 levels in female infants, in which PFDoA was the main contributor. This study suggested that prenatal exposure to PFAS mixtures is associated with fetal sex hormones, and long-chain PFAS may play an important role in this association. Furthermore, sex differences in the association of maternal PFAS exposure with E2 and P4 levels need additional attention.

Prenatal exposure to legacy PFAS and neurodevelopment in preschool-aged Canadian children: The MIREC cohort

BACKGROUND

Exposure to perfluoroalkyl substances (PFAS) has been shown to be neurotoxic in experimental studies, but epidemiological evidence linking prenatal PFAS exposure to child neurodevelopment is equivocal and scarce.

OBJECTIVE

To quantify associations between prenatal exposure to legacy PFAS and children's intelligence (IQ) and executive functioning (EF) in a Canadian pregnancy and birth cohort and to determine if these associations differ by child sex.

METHODS

We measured first-trimester plasma concentrations of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorohexanesulfonic acid (PFHxS) in the Maternal-Infant Research on Environmental Chemicals (MIREC) study and assessed children's full-scale (n = 522), performance (n = 517), and verbal (n = 519) IQ using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III). Children's working memory (n = 513) and ability to plan and organize (n = 514) were assessed using a parent-reported questionnaire, the Behavior Rating Inventory of Executive Function - Preschool Version (BRIEF-P). We quantified associations between individual log2-transformed PFAS exposure and children's IQ and EF using multiple linear regression analyses and evaluated effect modification by child sex. We also used Repeated Holdout Weighted Quantile Sum (WQS) regression models with effect modification by child sex to quantify the effect of combined exposure to all three PFAS chemicals on IQ and EF. All models were adjusted for key sociodemographic characteristics.

RESULTS

Geometric mean plasma concentrations (IQR) for PFOA, PFOS and PFHxS were 1.68 (1.10-2.50), 4.97 (3.20-6.20) and 1.09 (0.67-1.60) μg/L respectively. We found evidence of effect modification by child sex in all models examining performance IQ (p < .01). Specifically, every doubling of PFOA, PFOS, and or PFHxS was inversely associated with performance IQ, but only in males (PFOA: B = -2.80, 95% CI: -4.92, -0.68; PFOS: B = -2.64, 95% CI: -4.77, -0.52; PFHxS: B = -2.92, 95% CI: -4.72, -1.12). Similarly, every quartile increase in the WQS index was associated with poorer performance IQ in males (B = -3.16, 95% CI: -4.90, -1.43), with PFHxS contributing the largest weight to the index. In contrast, no significant association was found for females (B = 0.63, 95% CI: -0.99, 2.26). No significant associations were found for EF in either males or females.

CONCLUSIONS

Higher prenatal PFAS exposure was associated with lower performance IQ in males, suggesting that this association may be sex- and domain-specific.

Bioinformatics analysis and verification of hub genes in 46,XY, disorders of sexual development

CONTEXT

46,XY, disorders of sexual development (46,XY, DSD) is a congenital genetic disease whose pathogenesis is complex and clinical manifestations are diverse. The existing molecular research has often focused on single-centre sequencing data, instead of prediction based on big data.

AIMS

This work aimed to fully understand the pathogenesis of 46,XY, DSD, and summarise the key pathogenic genes.

METHODS

Firstly, the potential pathogenic genes were identified from public data. Secondly, bioinformatics was used to predict pathogenic genes, including hub gene analysis, protein-protein interaction (PPI) and function enrichment analysis. Lastly, the genomic DNA from two unrelated families were recruited, next-generation sequencing and Sanger sequencing were performed to verify the hub genes.

KEY RESULTS

A total of 161 potential pathogenic genes were selected from MGI and PubMed gene sets. The PPI network was built which included 144 nodes and 194 edges. MCODE 4 was selected from PPI which scored the most significant P -value. The top 15 hub genes were ranked and identified by Cytoscape. Furthermore, three variants were found on SRD5A2 gene by genome sequencing, which belonged to the prediction hub genes.

CONCLUSIONS

Our results indicate that occurrence of 46,XY, DSD is attributed to a variety of genes. Bioinformatics analysis can help us predict the hub genes and find the most core network MCODE model.

IMPLICATIONS

Bioinformatic predictions may provide a novel perspective on better understanding the pathogenesis of 46,XY, DSD.

Gene-environment interactions related to maternal exposure to environmental and lifestyle-related chemicals during pregnancy and the resulting adverse fetal growth: a review

Background

There are only limited numbers of reviews on the association of maternal-child genetic polymorphisms and environmental and lifestyle-related chemical exposure during pregnancy with adverse fetal growth. Thus, this article aims to review: (1) the effect of associations between the above highlighted factors on adverse fetal growth and (2) recent birth cohort studies regarding environmental health risks.

Methods

Based on a search of the PubMed database through August 2021, 68 epidemiological studies on gene-environment interactions, focusing on the association between environmental and lifestyle-related chemical exposure and adverse fetal growth was identified. Moreover, we also reviewed recent worldwide birth cohort studies regarding environmental health risks.

Results

Thirty studies examined gene-smoking associations with adverse fetal growth. Sixteen maternal genes significantly modified the association between maternal smoking and adverse fetal growth. Two genes significantly related with this association were detected in infants. Moreover, the maternal genes that significantly interacted with maternal smoking during pregnancy were cytochrome P450 1A1 (CYP1A1), X-ray repair cross-complementing protein 3 (XRCC3), interleukin 6 (IL6), interleukin 1 beta (IL1B), human leukocyte antigen (HLA) DQ alpha 1 (HLA-DQA1), HLA DQ beta 1 (HLA-DQB1), and nicotinic acetylcholine receptor. Fetal genes that had significant interactions with maternal smoking during pregnancy were glutathione S-transferase theta 1 (GSTT1) and fat mass and obesity-associated protein (FTO). Thirty-eight studies examined the association between chemical exposures and adverse fetal growth. In 62 of the 68 epidemiological studies (91.2%), a significant association was found with adverse fetal growth. Across the studies, there was a wide variation in the analytical methods used, especially with respect to the genetic polymorphisms of interest, environmental and lifestyle-related chemicals examined, and the study design used to estimate the gene-environment interactions. It was also found that a consistently increasing number of European and worldwide large-scale birth cohort studies on environmental health risks have been conducted since approximately 1996.

Conclusion

There is some evidence to suggest the importance of gene-environment interactions on adverse fetal growth. The current knowledge on gene-environment interactions will help guide future studies on the combined effects of maternal-child genetic polymorphisms and exposure to environmental and lifestyle-related chemicals during pregnancy.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00033.

Relationships between maternal perfluoroalkyl substance levels, polymorphisms of receptor genes, and adverse birth outcomes in the Hokkaido birth cohort study, Japan

We assessed the associations between perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) levels in third trimester maternal serum, the maternal genotypes of genes encoding nuclear receptors, and birth outcomes. We studied a prospective birth cohort of healthy pregnant Japanese women (n = 372) recruited in Sapporo between July 2002 and October 2005. We analyzed PFOS and PFOA levels using liquid chromatography-tandem mass spectrometry and analyzed 13 single nucleotide polymorphisms (SNPs) of proliferator-activated receptor alpha, gamma, gamma coactivator 1A, delta, constitutive androstane receptor, liver X receptor alpha, and beta (LXRB) using real-time polymerase reaction (PCR). We employed multiple linear regression models to establish the influences of log₁₀-transformed PFOS and PFOA levels and maternal genotypes on birth size. In female infants, we identified interactions between PFOS levels, the maternal genotype of LXRB (rs1405655), and birth weight. The estimated mean changes in birth weight in response to PFOS levels, the maternal genotype LXRB (rs1405655)-TC/CC (compared to TT), and their interactions were -502.9 g (95 % confidence interval [CI] = -247.3, -758.5 g), -526.3 g (95 % CI = -200.7, -852.0 g), and 662.1 g (95 % CI = 221.0, 1,103.2 g; p_int = 0.003), respectively. Interactions between PFOS levels and the maternal genotype of LXRB (rs1405655) also significantly affected birth chest circumference and the Ponderal index (p_int = 0.037 and 0.005, respectively). Thus, interactions between PFOS levels and the maternal genotype of LXRB (rs1405655) affects birth sizes in female infants. We found that certain SNPs modify the effects of PFOS levels on birth size.