Prenatal Triclosan Exposure and Anthropometric Measures Including Anogenital Distance in Danish Infants

Adverse impact of phthalate and polycyclic aromatic hydrocarbon mixtures on birth outcomes: A metabolome Exposome-Wide association study

It has been well-investigating that individual phthalates (PAEs) or polycyclic aromatic hydrocarbons (PAHs) affect public health. However, there is still a gap that the mixture of PAEs and PAHs impacts birth outcomes. Through innovative methods for mixtures in epidemiology, we used a metabolome Exposome-Wide Association Study (mExWAS) to evaluate and explain the association between exposure to PAEs and PAHs mixtures and birth outcomes. Exposure to a higher level of PAEs and PAHs mixture was associated with lower birth weight (maximum cumulative effect: 143.5 g) rather than gestational age. Mono(2-ethlyhexyl) phthalate (MEHP) (posterior inclusion probability, PIP = 0.51), 9-hydroxyphenanthrene (9-OHPHE) (PIP = 0.53), and 1-hydroxypyrene (1-OHPYR) (PIP = 0.28) were identified as the most important compounds in the mixture. In mExWAS, we successfully annotated four overlapping metabolites associated with both MEHP/9-OHPHE/1-OHPYR and birth weight, including arginine, stearamide, Arg-Gln, and valine. Moreover, several lipid-related metabolism pathways, including fatty acid biosynthesis and degradation, alpha-linolenic acid, and linoleic acid metabolism, were disturbed. In summary, these findings may provide new insights into the underlying mechanisms by which PAE and PAHs affect fetal growth.

Toxicity evolution of triclosan during environmental transformation and human metabolism: Misgivings in the post-pandemic era

In the context of pandemic viruses and pathogenic bacteria, triclosan (TCS), as a typical antibacterial agent, is widely used around the world. However, the health risks from TCS increase with exposure, and it is widespread in environmental and human samples. Notably, environmental transformation and human metabolism could induce potentially undesirable risks to humans, rather than simple decontamination or detoxification. This review summarizes the environmental and human exposure to TCS covering from 2004 to 2023. Particularly, health impacts from the environmental and metabolic transformation of TCS are emphasized. Environmental transformations aimed at decontamination are recognized to form carcinogenic products such as dioxins, and ultraviolet light and excessive active chlorine can promote the formation of these dioxin congeners, potentially threatening environmental and human health. Although TCS can be rapidly metabolized for detoxification, these processes can induce the formation of lipophilic ether metabolic analogs via cytochrome P450 catalysis, causing possible adverse cross-talk reactions in human metabolic disorders. Accordingly, TCS may be more harmful in environmental transformation and human metabolism. In particular, TCS can stimulate the transmission of antibiotic resistance even at trace levels, threatening public health. Considering these accruing epidemiological and toxicological studies indicating the multiple adverse health outcomes of TCS, we call on environmental toxicologists to pay more attention to the toxicity evolution of TCS during environmental transformation and human metabolism.

Association of Phenols, Parabens, and Their Mixture with Maternal Blood Pressure Measurements in the PROTECT Cohort

BACKGROUND

Phenols and parabens are two classes of high production volume chemicals that are used widely in consumer and personal care products and have been associated with reproductive harm and pregnancy complications, such as preeclampsia and gestational diabetes. However, studies examining their influence on maternal blood pressure and gestational hypertension are limited.

OBJECTIVES

We investigated associations between individual phenols, parabens, and their mixture on maternal blood pressure measurements, including systolic and diastolic blood pressure (SBP and DBP) and hypertension during pregnancy (defined as stage 1 or 2 hypertension), among N = 1,433 Puerto Rico PROTECT study participants.

METHODS

We examined these relationships cross-sectionally at two time points during pregnancy (16-20 and 24-28 wks gestation) and longitudinally using linear mixed models (LMMs). Finally, we used quantile g-computation to examine the mixture effect on continuous (SBP, DBP) and binary (hypertension during pregnancy) blood pressure outcomes.

RESULTS

We observed a trend of higher odds of hypertension during pregnancy with exposure to multiple analytes and the overall mixture [including bisphenol A (BPA), bisphenol S (BPS), triclocarbon (TCC), triclosan (TCS), benzophenone-3 (BP-3), 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), methyl paraben (M-PB), propyl paraben (P-PB), butyl paraben (B-PB), and ethyl paraben (E-PB)], especially at 24-28 wk gestation, with an adjusted mixture odds ratio ( OR ) = 1.57 (95% CI: 1.03, 2.38). Lower SBP and higher DBP were also associated with individual analytes, with results from LMMs most consistent for methyl paraben (M-PB) or propyl paraben (P-PB) and increased DBP across pregnancy [adjusted M-PB β = 0.78 (95% CI: 0.17, 1.38) and adjusted P-PB β = 0.85 (95% CI: 0.19, 1.51)] and for BPA, which was associated with decreased SBP (adjusted β = - 0.57 ; 95% CI: - 1.09 , - 0.05 ). Consistent with other literature, we also found evidence of effect modification by fetal sex, with a strong inverse association observed between the overall exposure mixture and SBP at visit 1 among participants carrying female fetuses only.

CONCLUSIONS

Our findings indicate that phenol and paraben exposure may collectively increase the risk of stage 1 or 2 hypertension during pregnancy, which has important implications for fetal and maternal health. https://doi.org/10.1289/EHP14008.

Association between prenatal phthalate exposure and ano-genital indices among offsprings in an Israeli cohort

Background

In-utero phthalate exposure was shown to be associated with shortened anogenital distance (AGD) in male newborns, but findings among female are inconsistent. While phthalate exposure among pregnant women in Israel is widespread, no study has examined the association with offspring AGD. The objective of the current study was to investigate the association between maternal phthalates urinary concentration and offspring AGD at time of delivery among a birth cohort in Israel.

Methods

We measured spot urinary concentration of monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), mono-2-ethyl-5-hydroxyhexylphthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) among women presenting to the delivery room at Shamir Medical Center in Israel. Birthweight, length and AGD were measured in all newborns using a standardized protocol. Each AGD measurement was adjusted to weight (ano-genital index). Confounders included socio-demographic characteristics, comorbidities and obstetrical history. Univariate and multivariate analyses assessed the associations between phthalates, confounders and AGD.

Results

Overall, 193 mother and infant were analyzed. All newborns were born at term and had normal Apgar scores. Mean maternal age was 32 ± 4.7 years old. Mean birth weight and pregnancy week were 3183 ± 498 g and 39 ± 1.3, respectively. Median (IQR) urinary phthalate concentration adjusted to creatinine (ug/g) were 3.96 (2.2-6.6), 1.22 (0.7-2), 10.84 (7-20.4), 6.36 (3.3-11.2) and 0.64 (0.4-1.1) for MBP, MBzP, MECPP, MEHHP and MEOHP, respectively. Univariate comparison showed a significant association between higher than median MBzP concentration, higher Ano-Fourchetal index (AFI: 4.4 vs. 4.1, p = 0.037) and Ano-clitoral index (ACI: 11.5 vs. 10.4, p = 0.032) in infants. Total urinary phthalates concentration ≥26.25 μg/g was significantly associated with smaller penile width index (3.5 vs. 3.7, p = 0.022), higher ACI (11.6 vs. 10.3, p = 0.013) and a trend towards significance for higher AFI (4.3 vs. 4.1, p = 0.055). Following multivariate linear regression only PWI remained significantly associated with total phthalate urinary concentration.

Conclusions

Maternal urinary phthalates concentration at delivery were not associated with female AGD, but total urinary phthalate concentration were inversely associated with penile width.

Gender-specific effects of polystyrene nanoplastic exposure on triclosan-induced reproductive toxicity in zebrafish (Danio rerio)

Nanoplastics (NPs) and triclosan (TCS) are ubiquitous emerging environmental contaminants detected in human samples. While the reproductive toxicity of TCS alone has been studied, its combined effects with NPs remain unclear. Herein, we employed Fourier transform infrared spectroscopy and dynamic light scattering to characterize the coexposure of polystyrene nanoplastics (PS-NPs, 50 nm) with TCS. Then, adult zebrafish were exposed to TCS at environmentally relevant concentrations (0.361-48.2 μg/L), with or without PS-NPs (1.0 mg/L) for 21 days. TCS biodistribution in zebrafish tissues was investigated using ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry. Reproductive toxicity was assessed through gonadal histopathology, fertility tests, changes in steroid hormone synthesis and gene expression within the hypothalamus-pituitary-gonad-liver (HPGL) axis. Transcriptomics and proteomics were applied to explore the underlying mechanisms. The results showed that PS-NPs could adsorb TCS, thus altering the PS-NPs' physical characteristics. Our observations revealed that coexposure with PS-NPs reduced TCS levels in the ovaries, livers, and brains of female zebrafish. Conversely, in males, coexposure with PS-NPs increased TCS levels in the testes and livers, while decreasing them in the brain. We found that co-exposure mitigated TCS-induced ovary development inhibition while exacerbated TCS-induced spermatogenesis suppression, resulting in increased embryonic mortality and larval malformations. This co-exposure influenced the expression of genes linked to steroid hormone synthesis (cyp11a1, hsd17β, cyp19a1) and attenuated the TCS-decreased estradiol (E2) in females. Conversely, testosterone levels were suppressed, and E2 levels were elevated due to the upregulation of specific genes (cyp11a1, hsd3β, cyp19a1) in males. Finally, the integrated analysis of transcriptomics and proteomics suggested that the aqp12-dctn2 pathway was involved in PS-NPs' attenuation of TCS-induced reproductive toxicity in females, while the pck2-katnal1 pathway played a role in PS-NPs' exacerbation of TCS-induced reproductive toxicity in males. Collectively, PS-NPs altered TCS-induced reproductive toxicity by disrupting the HPGL axis, with gender-specific effects.

Comprehensive insight into triclosan-from widespread occurrence to health outcomes

Humans are exposed to the variety of emerging environmental pollutant in everyday life. The special concern is paid to endocrine disrupting chemicals especially to triclosan which could interfere with normal hormonal functions. Triclosan could be found in numerous commercial products such as mouthwashes, toothpastes and disinfectants due to its antibacterial and antifungal effects. Considering the excessive use and disposal, wastewaters are recognized as the main source of triclosan in the aquatic environment. As a result of the incomplete removal, triclosan residues reach surface water and even groundwater. Triclosan has potential to accumulate in sediment and aquatic organisms. Therefore, the detectable concentrations of triclosan in various environmental and biological matrices emerged concerns about the potential toxicity. Triclosan impairs thyroid homeostasis and could be associated with neurodevelopment impairment, metabolic disorders, cardiotoxicity and the increased cancer risk. The growing resistance of the vast groups of bacteria, the evidenced toxicity on different aquatic organisms, its adverse health effects observed in vitro, in vivo as well as the available epidemiological studies suggest that further efforts to monitor triclosan toxicity at environmental levels are necessary. The safety precaution measures and full commitment to proper legislation in compliance with the environmental protection are needed in order to obtain triclosan good ecological status. This paper is an overview of the possible negative triclosan effects on human health. Sources of exposure to triclosan, methods and levels of detection in aquatic environment are also discussed.

Triclosan in paired-maternal and cord blood, and their relationships with congenital heart disease of baby

Prenatal triclosan (TCS) exposure has been reported to be associated with various birth outcomes and thyroid function, while the study of TCS exposure for congenital heart disease (CHD) patients is limited. In the present study, paired mother-fetus blood samples from CHD and healthy participants were collected to measure TCS exposure levels, and then check their relationship. Coupled with the concentrations of thyroid function biomarkers [free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), and thyroid antibodies (TgAb)] in maternal blood, we aimed to investigate whether the hormone-disrupting properties of TCS will affect its association with CHD. Our results indicated that the maternal TCS concentrations in the CHD group (median 0.31 ng/mL) were significantly lower than those in the control group (0.48 ng/mL, Mann Whitney U test, p = 0.01). Higher interquartile of TCS levels in maternal blood was associated with decrease odds of CHD (adjusted OR = 0.61, 95%CI: 0.41-0.91, p = 0.02). Maternal blood TCS higher than the cut-off value (25th quantile, 0.17 ng/mL) was significantly negatively associated with CHD risk (adjusted OR = 0.24, 95%CI: 0.09-0.62, p < 0.01). Besides, none of the thyroid biomarkers were significantly associated with maternal TCS exposure. However, maternal FT4 concentrations were positively correlated with TCS transplacental transfer rate and cord blood TCS levels (general linear regression, both p < 0.01). The results of molecular docking and dynamics simulation suggested that these correlations might be related to the transthyretin, a thyroid hormone-binding protein involved in the placental thyroid hormone transport system. Overall, our findings indicated that at normal exposure levels, the increase of maternal blood TCS concentration may have an inverse association with CHD, which merits further investigation.

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.

Associations between repeated measurements of childhood triclosan exposure and physical growth at 7 years

BACKGROUND

Epidemiological studies suggested that triclosan (TCS) exposure was ubiquitous among children and could affect their physical growth. However, most studies relied on TCS exposure at single time point, and the impacts of multiple time points TCS exposure were unclear.

OBJECTIVES

To estimate the associations between repeated TCS measurements in childhood (at ages 1, 2, 5, and 7 years) and physical growth at 7 years.

METHODS

This study included 206 children from Laizhou Wan Birth Cohort (LWBC), China. Urinary TCS concentrations were detected at age of 1, 2, 5, and 7 years, and physical growth including height, weight, waist circumference, and fat percentage was measured at 7 years. Multiple informant models were applied to examine the relationships of repeated TCS measurements in childhood with physical growth, and stratified analysis by gender was performed.

RESULTS

The detection rates of TCS at age of 1, 2, 5, and 7 years were above 60%, with median declining from 0.89 to 0.33 μg/g creatinine. We found TCS at 5 years was positively associated with waist-to-height ratio, and TCS at 7 years was positively associated with physical growth, including weight z-score, BMI z-score, waist circumference, waist-to-height ratio, and fat percentage. Moreover, the above associations for weight z-score, BMI z-score, and fat percentage significantly varied by the period of exposure (pint ˂ 0.05). After stratified by gender, positive associations were only found among boys.

CONCLUSIONS

In our study, TCS levels decreased as children's age increased. TCS exposures at age of 5 and 7 years were positively associated with physical growth at 7 years, and these associations were only significant in boys. Given the relatively small sample size, our findings should be interpreted with caution until confirmed by further investigation.

Benzophenones, bisphenols and other polychlorinated/phenolic substances in Danish infants and their parents - including longitudinal assessments before and after introduction to mixed diet

BACKGROUND

Humans are widely exposed to chemicals with known or suspected endocrine disrupting effects. Among those are several benzophenones, bisphenols and other phenols commonly used in consumer products.

OBJECTIVES

To provide human biomonitoring data from young families including infants and their parents as well as longitudinal data of infants exclusively breastfed versus on mixed diet.

METHOD

Twenty-two benzophenones, bisphenols and other phenols, were measured in urine sample sets collected from more than 100 infants and their parents (the TRIO study) and in paired samples from 61 infants when exclusively breastfed and after introduction of mixed diet (the FOOD study).

RESULTS

Twelve out of 22 substances were detectable in more than half of the urine samples from infants, mothers or fathers. Large variation in excreted levels of almost all the substances were observed. The TRIO study showed that infants had comparable or even significantly higher daily urinary excretion (DUE) of benzophenone, 4-hydroxy-benzophenone, bisphenol A, bisphenol S, triclosan and 2-phenylphenol than their parents. In the FOOD study, exclusively breastfed infants had higher or similar DUE of triclosan and benzophenones compared to when they received mixed diet. Urinary levels of triclosan and the benzophenones, BP-1 and BP-3 were significantly correlated between all trio members, indicating exposure from the same sources at home. For triclosan, BP-1 and BP-3, the within family variation was lower than between families in the TRIO study. Many substances were positively correlated both within infants and parents, indicating that some families were exposed to several of these substances concurrently.

CONCLUSION

Participants in this study excreted relatively low chemical levels, however, simultaneous exposure to several chemicals with endocrine disrupting abilities is of concern due to the dose-additive effects of these substances in combination with other chemicals.

Sex-specific associations between maternal exposure to parabens, phenols and phthalates during pregnancy and birth size outcomes in offspring

Current evidence on the effects of prenatal exposure to endocrine disrupting chemicals on birth size remains largely inconclusive. We aimed to investigate sex-specific associations between maternal exposure to parabens, phenols and phthalates during pregnancy and birth weight, length and head/abdominal circumferences. We performed a prospective study of 88 pregnant women who underwent amniocentesis in the period 2012 to 2014. Maternal urine samples were collected during pregnancy in weeks 12 to 36 (median: 18 weeks). The concentrations of parabens, phenols and individual phthalate diester metabolites were analyzed by isotope-diluted liquid chromatography-tandem mass spectrometry and osmolality adjusted. Linear regression models estimated the associations between urinary levels of selected compounds (tertile(T2-T3)_medium/high versus T1_low exposure) and birth size, stratified by offspring sex. A total of three parabens, two phenols, four individual phthalate metabolites and four sums of diester metabolites were detectable above limits of detection in at least 60% of urine samples. Overall, we observed few statistically significant associations, but medium/high exposure to bisphenol A (BPA) in male offspring was associated with statistically significant lower birth size across most outcomes [birth weight: -428 g (95% CI -756 to -99.4); birth length: -1.76 cm (95% CI -3.28 to -0.25); abdominal circumference: -1.97 cm (95% CI -3.55 to -0.39)]. Similarly, medium/high exposure to methyl paraben (MeP) in male offspring was associated with lower birth weight (-661 g, 95% CI -1251 to -70.7) and length (-3.11 cm, 95% CI -5.76 to -0.46) compared to low exposure. None of these associations were statistically significant in female offspring. Across all compounds, individual exposures were associated with more negative estimates of birth weight for male than for female offspring. Our study indicates that prenatal exposure to BPA and MeP may negatively affect birth size outcomes, with a possible sex effect. Given the small sample size, these findings need to be replicated in future larger studies.

Association between triclosan exposure and obesity measures among 7-year-old children in northern China

BACKGROUND

Triclosan (TCS) is a widely used synthetic antibacterial compound with ubiquitous human exposure. Animal studies have suggested the obesogenic effect of TCS exposure, but knowledge regarding its impacts on childhood obesity was limited.

OBJECTIVE

To investigate the associations of TCS exposure with childhood obesity in northern China.

METHODS

This study included 423 children who participated in the 7-year-old follow-up visits of Laizhou Wan Birth Cohort in Shandong, northern China. Children's TCS exposure were determined in spot urine samples via high performance liquid chromatography-tandem mass. Their height, weight, waist circumference, body fat percentage, body mass index (BMI), and waist-to-height ratio (WHtR) were measured or calculated. BMI z-score ≥ 85th percentile was defined as overweight/obesity, and WHtR ≥ 0.5 was considered to be abdominal obesity. Multivariable linear regressions, generalized linear models (GLMs), and multivariable logistic regressions were performed to examine the associations between TCS exposure and obesity measures in children.

RESULTS

Linear regressions showed that TCS concentrations, when treated as continuous variables, were positively associated with BMI z-score (β = 0.12, 95% CI: 0.01, 0.24) and body fat percentage (β = 0.82, 95% CI: 0.13, 1.52). When TCS concentrations were categorized as a four-level ordinal variable, the results of GLMs were similar those of continuous variables and both of the positive trends were significant (p-trend = 0.049 for BMI z-score; p-trend = 0.023 for body fat percentage). Moreover, the higher TCS levels versus reference group were associated with an approximate 2-3 fold increased risk of abdominal obesity (p-trend = 0.044).

CONCLUSION

Exposure to TCS was positively associated with obesity measures among 7-year-old children in northern, China. Given to the cross-sectional study design, a large prospective study is warranted to confirm our findings.

Maternal exposure to triclosan during lactation alters social behaviors and the hippocampal ultrastructure in adult mouse offspring

We recently reported that exposure to triclosan (TCS), a broad-spectrum antibacterial agent, affects social behaviors in adult mice, however, the long-lasting effects of TCS exposure during early life on social behaviors are still elusive. The present study aimed to investigate the long-lasting impacts of adding TCS to the maternal drinking water during lactation on the social behaviors of adult mouse offspring and to explore the potential mechanism underlying these effects. The behavioral results showed that TCS exposure decreased body weight, increased depression-like behavior and decreased social dominance in both male and female offspring, as well as increased anxiety-like behavior and bedding preference in female offspring. In addition, enzyme-linked immunosorbent assay (ELISA) indicated that TCS exposure increased peripheral proinflammatory cytokine levels, altered serum oxytocin (OT) levels, and downregulated the expression of postsynaptic density protein 95 (PSD-95) in the hippocampus. Morphological analysis by transmission electron microscopy (TEM) demonstrated that exposure to TCS induced morphological changes to synapses and neurons in the hippocampus of offspring. These findings suggested that TCS exposure during lactation contributed to abnormal social behaviors accompanied by increased peripheral inflammation and altered hippocampal neuroplasticity, which provides a deeper understanding of the effects of TCS exposure during early life on brain function and behavioral phenotypes.

Triclosan: A Small Molecule with Controversial Roles

Triclosan (TCS), a broad-spectrum antimicrobial agent, has been widely used in personal care products, medical products, plastic cutting boards, and food storage containers. Colgate Total^® toothpaste, containing 10 mM TCS, is effective in controlling biofilm formation and maintaining gingival health. Given its broad usage, TCS is present ubiquitously in the environment. Given its strong lipophilicity and accumulation ability in organisms, it is potentially harmful to biohealth. Several reports suggest the toxicity of this compound, which is inserted in the class of endocrine disrupting chemicals (EDCs). In September 2016, TCS was banned by the U.S. Food and Drug Administration (FDA) and the European Union in soap products. Despite these problems, its application in personal care products within certain limits is still allowed. Today, it is still unclear whether TCS is truly toxic to mammals and the adverse effects of continuous, long-term, and low concentration exposure remain unknown. Indeed, some recent reports suggest the use of TCS as a repositioned drug for cancer treatment and cutaneous leishmaniasis. In this scenario it is necessary to investigate the advantages and disadvantages of TCS, to understand whether its use is advisable or not. This review intends to highlight the pros and cons that are associated with the use of TCS in humans.

The Effect of Early Life Exposure to Triclosan on Thyroid Follicles and Hormone Levels in Zebrafish

Triclosan (TCS) is an antimicrobial chemical widely used in personal care products. Most of the TCS component is discharged and enters the aquatic ecosystem after usage. TCS has a similar structure as thyroid hormones that are synthesized by thyroid follicular epithelial cells, thus TCS has a potential endocrine disrupting effect. It is still not clear how the different levels of the environmental TCS would affect early development in vivo. This study examines the effects of TCS on thyroid hormone secretion and the early development of zebrafish. The fertilized zebrafish eggs were exposed to TCS at 0 (control), 3, 30, 100, 300, and 900 ng/mL, and the hatching rate and the larvae mortality were inspected within the first 14 days. The total triiodothyronine (TT₃), total thyroxine (TT₄), free triiodothyronine (FT₃), and free thyroxine (FT₄) were measured at 7, 14, and 120 days post-fertilization (dpf). The histopathological examinations of thyroid follicles were conducted at 120 dpf. TCS exposure at 30-300 ng/mL reduced the hatching rate of larvae to 34.5% to 28.2 % in the first 48 hours and 93.8 .7 % to 86.8 % at 72 h. Extremely high TCS exposure (900 ng/mL) strongly inhibited the hatching rate, and all the larvae died within 1 day. Exposure to TCS from 3 to 300 ng/mL reduced the thyroid hormones production. The mean TT₃ and FT₃ levels of zebrafish decreased in 300 ng/mL TCS at 14 dpf (300 ng/mL TCS vs. control : TT₃ , 0.19 ± 0.08 vs. 0.39 ± 0.06; FT₃, 19.21 ± 3.13 vs. 28.53 ± 1.98 pg/mg), and the FT₄ decreased at 120 dpf ( 0.09 ± 0.04 vs. 0.20 ± 0.14 pg/mg). At 120 dpf , in the 300 ng/mL TCS exposure group, the nuclear area and the height of thyroid follicular epithelial cells became greater, and the follicle cell layer got thicker. This happened along with follicle hyperplasia, nuclear hypertrophy, and angiogenesis in the thyroid. Our study demonstrated that early life exposure to high TCS levels reduces the rate and speed of embryos hatching, and induces the histopathological change of thyroid follicle, and decreases the TT₃, FT₃, and FT₄ production in zebrafish.

Prenatal exposure to phenols and benzophenones in relation to markers of male reproductive function in adulthood

INTRODUCTION

Environmental exposure during fetal life may disrupt testicular development. In humans, a limited number of studies have investigated whether these adverse effects persist into adulthood. Using data from a prospective, population-based birth cohort study, The Copenhagen Mother-Child cohort, the objective was to assess if there is an association between fetal exposure to selected phenols and benzophenones and markers of testicular function in adult men.

METHODS

Pregnant women were recruited in 1997-2001. Their sons were examined clinically at 18-20 years of age, with focus on adult markers of reproductive function (anogenital distance (AGD), semen quality and reproductive hormones). In total, 101 18-20-year-old men were included, whose mothers during pregnancy had a serum sample drawn and analyzed for bisphenol A (BPA) and seven other simple phenols, as well as six benzophenones. To investigate the association between chemical levels (in tertiles, T1-T3) in relation to markers of reproductive function, univariate and multiple linear regression analyses were performed.

RESULTS

In fully adjusted analyses, increased levels of luteinizing hormone (LH) were observed with higher fetal exposure to BPA (percentage difference (95%CI)) (T2: 12% (-8%,36%) and T3: 33% (10%,62%), compared to T1) and benzophenone-3 (BP-3) (T2: 21% (-2%,49%), T3: 18% (-4%,45%)), while no clear association was seen to total testosterone (TT). Higher levels of BPA and BP-3 were associated with a lower TT/LH ratio, although only significant for BPA (p-trend=0.01). No associations were seen to AGD or markers of semen quality.

CONCLUSION

In conclusion, high exposure to BPA and BP-3 was associated with a compensated reduced Leydig cell function but no other changes in markers of reproductive health. As maternal levels of BPA and BP-3 were not correlated, separate effects may be at play. Larger studies on long-term reproductive consequences of prenatal exposures are warranted to validate our findings.

PPARγ Regulates Triclosan Induced Placental Dysfunction

Exposure to the antibacterial agent triclosan (TCS) is associated with abnormal placenta growth and fetal development during pregnancy. Peroxisome proliferator-activated receptor γ (PPARγ) is crucial in placenta development. However, the mechanism of PPARγ in placenta injury induced by TCS remains unknown. Herein, we demonstrated that PPARγ worked as a protector against TCS-induced toxicity. TCS inhibited cell viability, migration, and angiogenesis dose-dependently in HTR-8/SVneo and JEG-3 cells. Furthermore, TCS downregulated expression of PPARγ and its downstream viability, migration, angiogenesis-related genes HMOX1, ANGPTL4, VEGFA, MMP-2, MMP-9, and upregulated inflammatory genes p65, IL-6, IL-1β, and TNF-α in vitro and in vivo. Further investigation showed that overexpression or activation (rosiglitazone) alleviated cell viability, migration, angiogenesis inhibition, and inflammatory response caused by TCS, while knockdown or inhibition (GW9662) of PPARγ had the opposite effect. Moreover, TCS caused placenta dysfunction characterized by the significant decrease in weight and size of the placenta and fetus, while PPARγ agonist rosiglitazone alleviated this damage in mice. Taken together, our results illustrated that TCS-induced placenta dysfunction, which was mediated by the PPARγ pathway. Our findings reveal that activation of PPARγ might be a promising strategy against the adverse effects of TCS exposure on the placenta and fetus.

Gestational triclosan exposure and infant birth weight: A systematic review and meta-analysis

BACKGROUND

Exposure to triclosan, an antimicrobial chemical used in some personal care and cleaning products, has been associated with reduced birth weight in some, but not all epidemiological studies.

OBJECTIVES

We conducted a systematic review and meta-analysis to characterize the relation of gestational triclosan exposure with infant birth weight and identify sources of heterogeneity between studies.

METHODS

We identified original studies measuring urinary triclosan concentrations during pregnancy and reporting their association with infant birth weight, gestational age (GA) adjusted birth weight (g), or GA-standardized birth weight z-scores. Using a random effects model, we estimated differences in these outcomes per 10-fold increase in triclosan concentrations and considered triclosan levels and infant sex as sources of heterogeneity. Using Navigation Guide Methods, we evaluated risk of bias within individual studies and across the body of evidence.

RESULTS

Among thirteen studies, median triclosan concentrations varied by almost 2-orders of magnitude (0.6-29 ng/mL), with higher concentrations in North American and some European studies compared to Asian ones. Associations between triclosan and birth weight (β:-20 g; 95% CI:-65, 26; n = 6) were stronger than those for GA-adjusted birth weight (β:-12 g; 95% CI:-29, 5; n = 9). Triclosan was not associated with GA-standardized birth weight z-scores (β:-0.04; 95% CI:-0.16, 0.07; n = 5). The association between triclosan and GA-adjusted birth weight was stronger in studies with median triclosan values ≥10 ng/mL compared to studies with median values < 10 ng/mL (β:-27 g; 95% CI:-61, 7; n = 4 vs. β:6g; 95% CI:-20, 31; n = 5). With a limited number of studies, we observed suggestive evidence that inverse associations were more apparent in studies with ≥ 2 prospective triclosan measures compared to those with one measure.

DISCUSSION

Available evidence, with "low" risk of bias, provides limited evidence that triclosan exposure and reduces infant birth weight. We observed stronger inverse associations between triclosan concentrations and birth weight in populations with higher triclosan exposure.

Effects of endocrine disruptors on fetal testis development, male puberty, and transition age

PURPOSE

Endocrine disruptors (EDs) are exogenous substances able to impair endocrine system; consequently, they may cause numerous adverse effects. Over the last years, particular focus has been given to their harmful effects on reproductive system, but very little is known, especially in males. The aim of this review is to discuss the detrimental effects of EDs exposure on fetal testis development, male puberty, and transition age.

METHODS

A search for the existing literature focusing on the impact of EDs on fetal testis development, male puberty, andrological parameters (anogenital distance, penile length, and testicular volume), and testicular cancer with particular regard to pubertal age provided the most current information available for this review. Human evidence-based reports were given priority over animal and in vitro experimental results. Given the paucity of available articles on this subject, all resources were given careful consideration.

RESULTS

Information about the consequences associated with EDs exposure in the current literature is limited and often conflicting, due to the scarcity of human studies and their heterogeneity.

CONCLUSIONS

We conclude that current evidence does not clarify the impact of EDs on human male reproductive health, although severe harmful effects had been reported in animals. Despite controversial results, overall conclusion points toward a positive association between exposure to EDs and reproductive system damage. Further long-term studies performed on wide number of subjects are necessary in order to identify damaging compounds and remove them from the environment.

Prenatal exposure to bisphenol A and autistic- and ADHD-related symptoms in children aged 2 and5 years from the Odense Child Cohort

BACKGROUND

Bisphenol A (BPA) is a non-persistent chemical with endocrine disrupting abilities used in a variety of consumer products. Fetal exposure to BPA is of concern due to the elevated sensitivity, which particularly relates to the developing brain. Several epidemiological studies have investigated the association between prenatal BPA exposure and neurodevelopment, but the results have been inconclusive.

OBJECTIVE

To assess the association between in utero exposure to BPA and Attention Deficit/Hyperactivity Disorder (ADHD-) symptoms and symptoms of Autism Spectrum Disorder (ASD) in 2 and 5-year old Danish children.

METHOD

In the prospective Odense Child Cohort, BPA was measured in urine samples collected in gestational week 28 and adjusted for osmolality. ADHD and ASD symptoms were assessed with the use of the ADHD scale and ASD scale, respectively, derived from the Child Behaviour Checklist preschool version (CBCL/1½-5) at ages 2 and 5 years. Negative binomial and multiple logistic regression analyses were performed to investigate the association between maternal BPA exposure (continuous ln-transformed or divided into tertiles) and the relative differences in ADHD and ASD problem scores and the odds (OR) of an ADHD and autism score above the 75th percentile adjusting for maternal educational level, maternal age, pre-pregnancy BMI, parity and child age at evaluation in 658 mother-child pairs at 2 years of age for ASD-score, and 427 mother-child pairs at 5 years of age for ADHD and ASD-score.

RESULTS

BPA was detected in 85.3% of maternal urine samples even though the exposure level was low (median 1.2 ng/mL). No associations between maternal BPA exposure and ASD at age 2 years or ADHD at age 5 years were found. Trends of elevated Odds Ratios (ORs) were seen among 5 year old children within the 3rd tertile of BPA exposure with an ASD-score above the 75th percentile (OR = 1.80, 95% CI 0.97,3.32), being stronger for girls (OR = 3.17, 95% CI 1.85,9.28). A dose-response relationship was observed between BPA exposure and ASD-score at 5 years of age (p-trend 0.06) in both boys and girls, but only significant in girls (p-trend 0.03).

CONCLUSION

Our findings suggest that prenatal BPA exposure even in low concentrations may increase the risk of ASD symptoms which may predict later social abilities. It is therefore important to follow-up these children at older ages, measure their own BPA exposure, and determine if the observed associations persist.

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.

Associations among urinary triclosan and bisphenol A concentrations and serum sex steroid hormone measures in the Canadian and U.S. Populations

Exposure to triclosan, an antimicrobial agent, and bisphenol A (BPA), the monomer of polycarbonate plastics, is widespread. Endocrine-disrupting impacts of these chemicals have been demonstrated in in vitro studies, rodent toxicology studies, and some human observational studies. Here we compared urinary concentrations of triclosan and BPA in the Canadian and U.S. populations using nationally-representative data from the 2012-2015 Canadian Health Measures Survey (CHMS) and the 2013-2016 National Health and Nutrition Examination Survey (NHANES). We then examined the cross-sectional associations of urinary triclosan or BPA with serum sex steroid hormones, including estradiol (E2), progesterone (P4), and testosterone (T), using multivariable regression. We observed differences in creatinine-standardized chemical concentrations between countries; urinary triclosan was higher in Canadian females aged 12-19 years, while BPA was higher in U.S. females aged 20-49 years. We also found significant associations among urinary chemicals and serum E2 and T, but not P4. Increasing triclosan was associated with higher levels of E2 in 6-11-year-old girls, but with lower levels of E2 and T in adolescent boys aged 12-19 years. Increasing BPA was associated with lower levels of E2 in 6-11-year-old boys and in adolescents aged 12-19 years of either sex. We observed a U-shaped association between urinary triclosan and E2 in male adults aged 50-79 years; no associations between BPA and hormones were detected in adults. These results, in accordance with the in vitro and animal literature, suggest that triclosan and BPA exposures may be cross-sectionally associated with altered reproductive hormone levels, especially in children and adolescents. Further research and prospective studies are necessary to elucidate country-specific differences in chemical exposures and the potential public health significance of these findings.

Hypothetical roadmap towards endometriosis: prenatal endocrine-disrupting chemical pollutant exposure, anogenital distance, gut-genital microbiota and subclinical infections

BACKGROUND

Endometriosis is a gynaecological hormone-dependent disorder that is defined by histological lesions generated by the growth of endometrial-like tissue out of the uterus cavity, most commonly engrafted within the peritoneal cavity, although these lesions can also be located in distant organs. Endometriosis affects ~10% of women of reproductive age, frequently producing severe and, sometimes, incapacitating symptoms, including chronic pelvic pain, dysmenorrhea and dyspareunia, among others. Furthermore, endometriosis causes infertility in ~30% of affected women. Despite intense research on the mechanisms involved in the initial development and later progression of endometriosis, many questions remain unanswered and its aetiology remains unknown. Recent studies have demonstrated the critical role played by the relationship between the microbiome and mucosal immunology in preventing sexually transmitted diseases (HIV), infertility and several gynaecologic diseases.

OBJECTIVE AND RATIONALE

In this review, we sought to respond to the main research question related to the aetiology of endometriosis. We provide a model pointing out several risk factors that could explain the development of endometriosis. The hypothesis arises from bringing together current findings from large distinct areas, linking high prenatal exposure to environmental endocrine-disrupting chemicals with a short anogenital distance, female genital tract contamination with the faecal microbiota and the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis.

SEARCH METHODS

We performed a search of the scientific literature published until 2019 in the PubMed database. The search strategy included the following keywords in various combinations: endometriosis, anogenital distance, chemical pollutants, endocrine-disrupting chemicals, prenatal exposure to endocrine-disrupting chemicals, the microbiome of the female reproductive tract, microbiota and genital tract, bacterial vaginosis, endometritis, oestrogens and microbiota and microbiota-immune system interactions.

OUTCOMES

On searching the corresponding bibliography, we found frequent associations between environmental endocrine-disrupting chemicals and endometriosis risk. Likewise, recent evidence and hypotheses have suggested the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis. Hence, we can envisage a direct relationship between higher prenatal exposure to oestrogens or estrogenic endocrine-disrupting compounds (phthalates, bisphenols, organochlorine pesticides and others) and a shorter anogenital distance, which could favour frequent postnatal episodes of faecal microbiota contamination of the vulva and vagina, producing cervicovaginal microbiota dysbiosis. This relationship would disrupt local antimicrobial defences, subverting the homeostasis state and inducing a subclinical inflammatory response that could evolve into a sustained immune dysregulation, closing the vicious cycle responsible for the development of endometriosis.

WIDER IMPLICATIONS

Determining the aetiology of endometriosis is a challenging issue. Posing a new hypothesis on this subject provides the initial tool necessary to design future experimental, clinical and epidemiological research that could allow for a better understanding of the origin of this disease. Furthermore, advances in the understanding of its aetiology would allow the identification of new therapeutics and preventive actions.

Triclosan and triclocarbon in maternal-fetal serum, urine, and amniotic fluid samples and their implication for prenatal exposure

Triclosan (TCS) and Triclocarbon (TCC) are chlorinated synthetic antimicrobial agents formaternal urinelated in quantities of consumer products. However, the biomonitoring of direct exposure reflection for fetuses are rare. In this study, we determine the concentrations of TCS and TCC in paired maternal serum, cord serum, maternal urine, and amniotic fluid samples collected from a cohort of 95 expecting mother-fetal pairs in Southern China. TCS and TCC are detected widely (detection rates: >76.9%) in maternal serum, cord serum, maternal urine, and amniotic fluid samples. TCS is found to be the predominant antimicrobial agent with median concentrations in maternal serum (1.5 ng/mL) and cord serum (1.8 ng/mL) that are one order of magnitude higher than those of tcc in maternal serum (0.085 ng/mL) and cord serum (0.052 ng/mL), respectively. Cord serum concentrations of tcs and tcc correlated well with the concentrations in maternal serum, which reflect the mothers' contribution to fetal exposure. The higher median ratio of cord serum/maternal serum_TCS (0.95) compared to that of cord serum/maternal serum_TCC (0.53) indicates high placental transmission ability of TCS. Moreover, the facility to penetrate the placental barrier and hard to depurate characteristics lead to the long residence of TCS in the fetal environment, causing great concern over the prenatal exposure risks during the critical window of fetal development. This study provides a novel contribution by increasing existing knowledge on the exposure assessment of TCS and TCC during pregnancy through the exploration of matched maternal-fetal samples.

Associations of prenatal exposure to multiple metals with testicular volume and anogenital distance in infant boys: A longitudinal cohort study

BACKGROUND

Human are widely exposed to multiple metals, some of which have suspected reproductive toxicity, but no human studies have investigated the developmental effects of prenatal metal exposure.

OBJECTIVES

We aimed to evaluate the associations between prenatal multiple metal exposure and reproductive development in boys at 2-3 years using multi-pollutant approach.

METHODS

This prospective study used data of 564 mother-child pairs recruited from the Guangxi Birth Cohort Study. Twenty serum metal concentrations were measured. Least absolute shrinkage and selection operator (LASSO) penalized regression was used to identify independent associations between prenatal multiple metal exposure and testicular volume (TV), and anogenital distance (AGD). Adjusted estimates were then obtained using multiple linear regression analysis, and the regression tree method was used to explore the interactions.

RESULTS

Boys in the highest quartile of prenatal lead exposure had a 0.064 mL (95% CI: -0.124, -0.004) smaller ln-transformed TV, 0.060 cm (95% CI: -0.110, -0.011) shorter ln-transformed anopenile distance (AGDap), and 0.115 cm (95% CI: -0.190, -0.039) shorter ln-transformed anoscrotal distance (AGDas) than boys in the lowest quartile (all Ptrend < 0.05). Chromium was inversely with ln-transformed AGDap (β = -0.078, 95% CI: -0.127, -0.030) and ln-transformed AGDas (β = -0.113, 95% CI: -0.188, -0.038), while stibium was positivity associated with ln-transformed AGDap (β = 0.091, 95% CI: 0.046, 0.136) and strontium was positivity associated with ln-transformed AGDas (β = 0.120, 95% CI: 0.051, 0.189) (all Ptrend < 0.05). And the critical window of vulnerability may be the late pregnancy (the second and third trimester). Moreover, we detected interaction effects between lead, chromium and stibium on AGDap; lead, chromium and strontium on AGDas.

CONCLUSIONS

The results suggest that prenatal exposure to lead, chromium, stibium and strontium may affect TV and/or AGD in infant boys. Potential mechanisms for the complex metal interactive effects during vulnerable periods are worthy of further investigation.

Impact of prenatal triclosan exposure on gestational age and anthropometric measures at birth: A systematic review and meta-analysis

Background:

Exposure to endocrine disrupting chemicals such as triclosan (TCS) leads to disrupting the endocrine system and consequently effect on the birth outcomes. The findings of studies in this field are controversial.

Materials and Methods:

This systematic review and meta analysis was conducted based on the identified published papers in Scopus, Web of Science, and PubMed up to November 2019. All steps, including searching, screening, data extracting, and quality assessment, were done by two independent researchers.

Results:

Finally 15 published papers selected. The number of participants in whom the association of TCS exposure was assessed with birth weight, birth length, birth head circumference, and gestational age were 9112, 4311, 2854, and 3181 mother infant pairs, respectively. The pooled analysis showed that TCS exposure during pregnancy leads to increasing the birth weight for boys with β= 3.97 and 95% confidence interval (CI) (−3.98, 11.92), and girls with β= 5.37, 95% CI (−6.00, 16.75), but the association was not statistically significant. In addition, according to fixed effects models, the TCS exposure was not significantly associated with birth length (−0.008, 95% CI [−0.049, 0.034]), birth head circumference (−0.01, 95% CI [−0.08, 0.06]), and gestational age (−0.005, 95% CI [−0.017, 0.006]). Likewise, analysis for data segregated by gender of infants revealed similar results.

Conclusion:

The obtained results depicted that the TCS exposure during pregnancy period was associated with higher birth weight for boys and girls. No significant association was observed for TCS exposure with variation of birth length, head circumference, and gestational age duration. In fact, the results showed the evidence of null associations between maternal TCS exposure and birth outcomes.

Exposure to phenols during pregnancy and the first year of life in a new type of couple-child cohort relying on repeated urine biospecimens

BACKGROUND

Parabens, bisphenol A and triclosan have been forbidden or restricted in specific types of consumer goods in Europe and France. Limited biomonitoring data are available in France since the implementation of these regulations, and exposure data on infants is scarce worldwide. Understanding the predictors of phenol urinary concentrations will help identify potential targets for prevention.

AIM

We described levels, variability and predictors of exposure to 12 phenols in pregnant women and infants recruited between 2014 and 2017 in a French couple-child cohort.

METHODS

Among 479 pregnant women and 150 of their infants, we studied phenol urinary concentrations in within-subject, within-period pools of repeated urine samples collected during the second and third trimesters of pregnancy (up to 42 samples per woman), at 2 months and 12 months (up to 14 samples per infant). Time trends and associations with demographic, protocol, occupational and behavioral factors were studied using interval censored models to accommodate for undetected and unquantified urine concentrations.

RESULTS

Detection rates were above 90% for bisphenol A, ethylparaben, methylparaben, benzophenone-3 and triclosan and below 5% for bisphenol AF, B, F and triclocarban. Median levels of bisphenol A, bisphenol S, methylparaben, ethylparaben and propylparaben at 12 months were similar or higher than during pregnancy. For pregnant women all phenols but benzophenone-3 and bisphenol S showed a linear decrease between 2014 and 2017 (p-values < 0.02). Women with the shortest education (primary and secondary school) had higher urinary concentrations of triclosan (β = 0.58 (95% confidence interval (CI), -0.04; 1.20)), ethyl (β = 0.43 (95%CI, 0.03; 0.84)) and propyl paraben (β = 1.39 (95%CI, 0.55; 2.24)) than those with the longest education. Cashiers had higher conccentrations of bisphenol S (β = 0.99 (95%CI, -0.11; 2.09)) but not of bisphenol A (β = -0.04 (95%CI, -0.26; 0.19)) than unemployed women.

CONCLUSIONS

Despite recent regulations, bisphenol A, triclosan and paraben detection rates were high in women and young infants. High bisphenol and paraben median levels at 12 months require further investigation as early infancy is a sensitive period for exposure to environmental contaminants.

Prenatal urinary concentrations of environmental phenols and birth outcomes in the mother-infant pairs of Tehran Environment and Neurodevelopmental Disorders (TEND) cohort study

Daily exposure to environmental phenols can lead to potential undesirable effects on the health of pregnant women and fetuses. The present study is aimed to evaluate the relationship between maternal urinary concentrations of phenols in pregnancy and anthropometric birth outcomes. The studied population comprised of 189 pregnant women participating in the Tehran Environment and Neurodevelopmental Disorders (TEND) prospective cohort study, which had been ongoing since March 2016 in some hospitals and health care delivery centers in Tehran, Iran. Concentrations of bisphenol-A, triclosan, 4-nonylphenol, and parabens were determined in spot urine samples of pregnant mothers in the first trimester. Weight, length, and head circumference at birth were also extracted from the mothers' delivery files. Multivariable linear regression was used to examine the relationship between log-concentrations of phenols and birth outcomes. When we analyzed all samples regardless of neonates' gender, none of the urinary concentrations of phenols were associated with weight and length at birth. Indeed, in sex-stratified adjusted models, one log-unit increase of butylparaben was related to a 283.6 g (95% CI: 23, 544) increase in boys' birth weight. Prenatal urinary concentration of triclosan and propylparaben was respectively related to a decrease of 4.8 cm (95% C: -8.5, -1.1) in boys' length and 0.9 cm (95%CI: -1.8, -0.04) in girls' length. In the adjusted models for estimating the changes in head circumference, one log-unit increase of triclosan, methylparaben, and butylparaben led to a reduction of 1.6 cm (95% CI: -3.17, 0.03), increase of 0.8 cm (95% CI: -0.01, 1.6) and 0.7 cm (95% CI: 0.08, 1.4) in head circumference at birth respectively. Our results suggested that prenatal triclosan and parabens exposure might be associated with head circumference at birth. Furthermore, we observed a sexually dimorphic pattern between maternal triclosan and parabens exposure during pregnancy and fetal growth. However, these findings must be interpreted while taking into account the limitations of this study.

Interactions between chemicals and non-chemical stressors: The modifying effect of life events on the association between triclocarban, phenols and parabens with gestational length in a Puerto Rican cohort

BACKGROUND

Phenols and parabens are common additives to consumer products. There is evidence of adverse birth outcomes in association with prenatal exposure to these chemicals, in addition to psychosocial factors. We previously reported an increase in gestational length with bisphenol-A, methylparaben and propylparaben, and a decrease in gestational length with triclocarban.

OBJECTIVES

We examined the modifying effect of psychosocial stress on the association between chemicals and gestational length in up to 752 women among a pregnancy cohort study.

METHODS

Urinary biomarkers were measured at up to three time points in pregnancy. Multiple linear regression models were conducted to investigate the association between gestational length and the interaction between average exposure biomarkers and LES. Multiple linear regression models regressing the exposure biomarkers in relation to gestational length were also stratified by LES, Negative LES, and Positive LES, based on the subjective ratings of events. Results were transformed into the change in gestational length for an inter-quartile-range difference in the exposure.

RESULTS

Of the four psychosocial stress measures, only the life events score (LES) was a significant modifier. Associations between triclocarban, bisphenol-S, methyl- and propylparaben in relation to gestational length were stronger among women with negative Total LES scores. Among women with negative Total LES scores, bisphenol-S and triclocarban were associated with a 3-5 day decrease in gestational length [(-3.15; 95% CI: -6.06, -0.24); (-4.68; 95% CI: -8.47, -0.89)], whereas methylparaben and propylparaben were associated with a 2-3 day increase in gestational length [(2.21; 95% CI: 0.02, 4.40); (2.92; 95% CI: 0.58, 5.26)]. Significant interactions were driven by negative life events, but the association with triclocarban was driven by few positive life events.

CONCLUSIONS

Associations between exposure biomarkers and gestational length were stronger in the presence of negative life events. This provides evidence that stress makes the body more vulnerable to chemical exposure.

Association of blood metal exposure with testosterone and hemoglobin: A cross-sectional study in Hangzhou Birth Cohort Study

BACKGROUND

Few epidemiological studies have investigated associations of exposure to multiple metals with testosterone homeostasis and erythropoiesis, especially for the pregnant women.

METHODS

Among all the 1644 participants enrolled in Hangzhou Birth Cohort Study (HBCS) at baseline, a total of 918 pregnant women with complete data of interest were analyzed. The whole blood metals levels were examined by inductively coupled plasma mass spectrometry (ICP-MS), and serum testosterone level was evaluated by chemiluminescent microparticle immunoassay (CMIA), and erythropoietic parameters values were extracted from medical record. Multivariable linear regression models were applied to estimate the relationships between metals levels and testosterone level, and between metals levels and erythropoietic parameters, and potential confounders were adjusted.

RESULTS

Single metal model analysis revealed a significant association of blood As, Mn and Pb level with serum testosterone level. After controlling for multiple testing, the dose-response trend with statistical significance (FDR-adjusted p trend <0.05) was observed across tertiles of Pb with testosterone. This association, when by stratified by gender, remained in pregnant women with a male fetus but did not reach significant in those with a female fetus. Furthermore, blood Pb level was positively associated with red blood cell counts, hemoglobin level and hematocrit. Serum testosterone level was positively associated with red blood cell counts, hemoglobin level and hematocrit. Mediation analyses indicated that testosterone might act as a mediator in the association between Pb exposure and erythropoietic parameters.

CONCLUSIONS

Serum testosterone level and hemoglobin level was positively related to blood Pb level among Chinese pregnant women, and testosterone might mediate the effect of Pb exposure on hemoglobin. Additional prospective studies are warranted to confirm the causality.

Association of prenatal exposure to phenols and parabens with birth size: A systematic review and meta-analysis

Phenols and parabens are endocrine-disrupting chemicals and are widely used in daily life products due to their antibacterial action. Previous studies suggest associations of prenatal exposure to phenols and parabens with fetal development; however, such findings are rare and inconsistent. The aim of this review and meta-analysis is to estimate the associations between maternal exposure to phenols and parabens and birth size. We identified 21 relevant studies that met the inclusion criteria through databases of PubMed, Cochrane, EMBASE and Qvid Medline. The last search was in July 3, 2019. The heterogeneity and possibility of publication bias among included studies were assessed by Q-statistic and Begg's test, respectively. Meta-analysis revealed that prenatal exposure to triclosan [number of studies (n) = 12, regression coefficient (β) = -0.04 g; 95% confidence interval (CI): -0.139, 0.059], benzophenone-3 (n = 10, β = -0.001 g; 95% CI: -0.013, 0.012), bisphenol A (n = 9, β = -0.049 g; 95% CI: -0.199, 0.101), 2-4-dichlorophenols (n = 6, β = -14.124 g; 95% CI: -29.971, 1.723), 2-5-dichlorophenols (n = 6, β = -0.061 g; 95% CI: -0.196, 0.074) and parabens were negatively associated with fetal birth weight. Most of them were insignificant. Inconsistent and insignificant associations were detected between exposure to phenols and parabens and other birth outcomes. Subgroup analysis suggested that heterogeneity in our meta-analysis was mainly attributed to the studies conducted in developed countries and samples collected in the second trimester. Insignificant and controversial associations of maternal exposure to phenols and parabens with birth size were observed in our study. The study design and methods of the included studies are inconsistent, and the effects of environmental pollutants on human health are complex. Further cohort studies with large samples and a consistent approach are thus required to evaluate the associations of maternal exposure to phenols and parabens with birth size.

Exposure to triclosan among pregnant women in northern China: urinary concentrations, sociodemographic predictors, and seasonal variability

Although triclosan (TCS) use is widespread in China, little is known about levels of exposure to TCS in pregnant women and its potential predictors, sources, and seasonal variability. We assessed urinary TCS levels of 466 pregnant women in a Chinese cohort. The estimated daily intake (EDI) and hazard quotient (HQ) were calculated. Potential predictors and sources were collected through a questionnaire and the seasonal variability was recorded based on the time of sampling. The geometric mean of urinary TCS concentration was 0.81 μg/g. The 95th EDI was 0.15 μg/kg BW per day and the corresponding HQ was 3.23 × 10^-3. Women with a household monthly salary between RMB (¥) 1000 and 3000 and between RMB (¥) 3000 and 5000 had 0.52 μg/g (95% CI 0.08, 0.75) and 0.58 μg/g (95% CI 0.17, 0.79) lower urinary TCS levels than those with a household monthly salary of < RMB (¥) 1000, respectively. Urine samples collected in winter had lower TCS levels (geometric mean 0.72 μg/g) than in spring, summer, and autumn (geometric mean 0.82, 0.84, and 0.86 μg/g), although they were non-significant (P = 0.648). No association was found between drinking water and food consumed during pregnancy and TCS levels. The study population was ubiquitously exposed to a relatively low and safe dose of TCS. Women with lower household income tended to be exposed to higher levels of TCS.

In utero exposure to persistent and nonpersistent endocrine-disrupting chemicals and anogenital distance. A systematic review of epidemiological studies†

Anti-androgenic endocrine-disrupting chemicals (EDCs) can cross the placenta to modify early offspring sexual dimorphic markers. These changes are linked to anogenital distance (AGD), which is an androgen-sensitive anthropometric parameter used as a biomarker of perineal growth and caudal migration of the genital tubercle. This review aimed to summarize strength of evidence for associations of in utero exposure to EDCs with AGD and to identify gaps and limitations in the literature so as to inform future research. We performed an electronic search of English literature in September 2019 in medical literature analysis and retrieval system online (MEDLINE), Web of Science and Toxline. We included epidemiological studies that examined in utero exposure to persistent and nonpersistent EDCs and considered AGD in offspring as an outcome. Our review contained 16 investigations examining exposure to persistent EDCs (nine studies) and nonpersistent EDCs (seven studies). Some individual studies reported an inverse association between exposure to bisphenol A (BPA), dioxins, perfluoroalkyl substances, and organochlorides and AGD in both male and female offspring. Meta-analysis of three studies found a small reduction of AGD in female offspring exposed to BPA. The number of studies per chemical is small, and number of subjects examined is limited; so, replication of these results is needed. To achieve more specificity and better replication of results, future studies should establish the association of nonpersistent EDCs using multiple urine samples, evaluate the cumulative impact of exposure to a mixture of anti-androgenic chemicals, and offer adequate consideration of more maternal- and children-related confounding factors.

Exposure to environmental pollutants and a marker of early kidney injury in the general population: Results of a nationally representative cross-sectional study based on the Korean National Environmental Health Survey (KoNEHS) 2012-2014

Exposure to environmental pollutants may lead to early kidney injury, chronic kidney disease (CKD) and end-stage renal disease (ESRD). This study investigated the early renal effects associated with exposure to endocrine-disrupting chemicals (EDCs) and heavy metals using general Korean population data. We used data from the Second Korean National Environmental Health Survey (2012-2014). As exposure markers, the concentrations of EDCs, such as triclosan (TCS), bisphenol A (BPA) and phthalate metabolites (DEHP, MnBP and MBzP), and heavy metals, such as cadmium, lead and mercury were analyzed. As an early kidney injury marker, the urinary concentration of β₂-microglobulin (β₂M) was measured. Multiple linear regression was used to analyze the relationship between environmental pollutants and β₂M. A total of 5489 people (male: 2538, female: 2951) aged 19 years and older were enrolled. The geometric mean (GM) concentration of β₂M in the total population was 1.88 μg/g creatinine (95% confidence interval (CI) 1.85-1.91). The β₂M concentrations were significantly higher in cases of female, old age, low income, and presence of a history of diabetes mellitus or hypertension. The GM concentrations of urinary TCS and cadmium were 1.16 μg/g creatinine (95% CI 1.11-1.21) and 0.57 μg/g creatinine (95% CI 0.57-0.59), respectively. TCS, DEHP, cadmium, lead, and mercury exposure was significantly positively related to urinary β₂M in the multiple regression analysis. β₂M levels increased significantly with increases in the cadmium, mercury, and lead levels (p for trend <0.0001). The higher the DEHP, MnBP, and TCS concentrations, the higher the β₂M level (p for trend <0.01). Environmental pollutants exposure significantly increased urinary β₂M levels in the general Korean population. To prevent the development of early kidney injury and CKD, it is important to reduce environmental pollutants exposure through regulatory measures, and cooperation between related bodies in both developing and developed countries.

Use of antibacterial toothpaste is associated with higher urinary triclosan concentrations in Asian immigrant women living in Vancouver, Canada

BACKGROUND

Triclosan is an antibacterial added to consumer products including toothpastes, cosmetics, and plastic cutting boards. Known to disrupt reproductive and hormonal functioning in animals, epidemiological studies indicate that exposure to triclosan may have similar effects on human health.

METHODS

100 women aged 19 to 45 years born in India or China, Hong Kong, and Taiwan new to the Vancouver (Canada) area were recruited in 2015-2016 by word of mouth, public advertisements, and contacts in health and cultural organizations. Participants completed an interview which queried potential sources of triclosan exposure at home and at work and their urine was tested for triclosan by GC-MS. Determinants of urinary triclosan were assessed by Wilcoxon signed-rank test.

RESULTS

Triclosan was detected in 62% of urine samples, with an overall GM of 14.5 μg/L (95% CI: 9.7-21.7 μg/L; range: <LOD to 1900 μg/L). Colgate Total® toothpaste users had higher urinary triclosan concentrations (median = 34.0 μg/L) than non-users (median = 2.5 μg/L, ρ < 0.001), a result which was unaffected by adjustment for age, income, BMI, and country of birth. South Asian born women had elevated urinary triclosan compared to East Asian born women.

CONCLUSION

Triclosan exposure via a specific antibacterial toothpaste brand was identified in reproductive age newcomer women in Canada. Health education around brushing teeth well while using lower toothpaste volumes or choosing triclosan-free toothpaste would reduce triclosan exposure.

Fetal growth in environmental epidemiology: mechanisms, limitations, and a review of associations with biomarkers of non-persistent chemical exposures during pregnancy

BACKGROUND

Non-persistent chemicals, such as phthalates, environmental phenols, organophosphate pesticides, and others, are challenging to study because of their ubiquity in the environment, diverse exposure routes, and high temporal variability of biomarkers. Nonetheless, there is interest in understanding how gestational exposure to these chemicals may affect fetal growth, as perturbations to normal fetal growth are related to a plethora of adverse health outcomes in childhood and adulthood.

METHODS

The purpose of this review is to describe the state of the science on this topic. We searched PubMed for studies that included both 1) biomarkers of non-persistent chemicals collected during pregnancy and 2) fetal growth outcomes measured at birth (e.g., birth weight) or by ultrasound in utero (e.g., estimated fetal weight).

RESULTS

The bulk of the literature we found uses biomarkers measured at a single time point in pregnancy and birth weight as the primary measure of fetal growth. There is a small, but growing, body of research that uses ultrasound measures to assess fetal growth during pregnancy. In addition to summarizing the findings of the publications we identified, we describe inconsistencies in methodology, areas for improvement, and gaps in existing knowledge that can be targeted for improvement in future work. This literature is characterized by variability in methodology, likely contributing to the inconsistency of results reported. We further discuss maternal, placental, and fetal pathways by which these classes of chemicals may affect fetal growth.

CONCLUSIONS

To improve understanding of how everyday chemical exposures affect fetal growth, and ultimately lifelong health outcomes, mechanisms of toxicant action should be considered alongside improved study designs for future hypothesis-driven research.

A repeated measures study of phenol, paraben and Triclocarban urinary biomarkers and circulating maternal hormones during gestation in the Puerto Rico PROTECT cohort

INTRODUCTION

Prenatal exposure to some phenols and parabens has been associated with adverse birth outcomes. Hormones may play an intermediate role between phenols and adverse outcomes. We examined the associations of phenol and paraben exposures with maternal reproductive and thyroid hormones in 602 pregnant women in Puerto Rico. Urinary triclocarban, phenol and paraben biomarkers, and serum hormones (estriol, progesterone, testosterone, sex-hormone-binding globulin (SHBG), corticotropin-releasing hormone (CRH), total triiodothyronine (T3), total thyroxine (T4), free thyroxine (FT4) and thyroid-stimulating hormone (TSH)) were measured at two visits during pregnancy.

METHODS

Linear mixed models with a random intercept were constructed to examine the associations between hormones and urinary biomarkers. Results were additionally stratified by study visit. Results were transformed to hormone percent changes for an inter-quartile-range difference in exposure biomarker concentrations (%Δ).

RESULTS

Bisphenol-S was associated with a decrease in CRH [(%Δ -11.35; 95% CI: -18.71, - 3.33), and bisphenol-F was associated with an increase in FT4 (%Δ: 2.76; 95% CI: 0.29, 5.22). Butyl-, methyl- and propylparaben were associated with decreases in SHBG [(%Δ: -5.27; 95% CI: -9.4, - 1.14); (%Δ: -3.53; 95% CI: -7.37, 0.31); (%Δ: -3.74; 95% CI: -7.76, 0.27)]. Triclocarban was positively associated with T3 (%Δ: 4.08; 95% CI: 1.18, 6.98) and T3/T4 ratio (%Δ: 4.67; 95% CI: -1.37, 6.65), and suggestively negatively associated with TSH (%Δ: -10.12; 95% CI: -19.47, 0.32). There was evidence of susceptible windows of vulnerability for some associations. At 24-28 weeks gestation, there was a positive association between 2,4-dichlorophenol and CRH (%Δ: 9.66; 95% CI: 0.67, 19.45) and between triclosan and estriol (%Δ: 13.17; 95% CI: 2.34, 25.2); and a negative association between triclocarban and SHBG (%Δ: -9.71; 95% CI:-19.1, - 0.27) and between bisphenol A and testosterone (%Δ: -17.37; 95% CI: -26.7, - 6.87).

CONCLUSION

Phenols and parabens are associated with hormone levels during pregnancy. Further studies are required to substantiate these findings.

The associations between prenatal exposure to triclocarban, phenols and parabens with gestational age and birth weight in northern Puerto Rico

BACKGROUND

Prenatal exposure to certain xenobiotics has been associated with adverse birth outcomes. We examined the associations of triclocarban, phenols and parabens in a cohort of 922 pregnant women in Puerto Rico, the Puerto Rico Testsite for Exploring Contamination Threats Program (PROTECT).

METHODS

Urinary triclocarban, phenols and parabens were measured at three time points in pregnancy (visit 1: 16-20 weeks, visit 2: 20-24 weeks, visit 3: 24-28 weeks gestation). Multiple linear regression (MLR) models were conducted to regress gestational age and birthweight z-scores against each woman's log average concentrations of exposure biomarkers. Logistic regression models were conducted to calculate odds of preterm birth, small or large for gestational age (SGA and LGA) in association with each of the exposure biomarkers. An interaction term between the average urinary biomarker concentration and infant sex was included in models to identify effect modification. The results were additionally stratified by study visit to look for windows of vulnerability. Results were transformed into the change in the birth outcome for an inter-quartile-range difference in biomarker concentration (Δ).

RESULTS

Average benzophenone-3, methyl- and propyl-paraben concentrations were associated with an increase in gestational age [(Δ 1.90 days; 95% CI: 0.54, 3.26); (Δ 1.63; 95% CI: 0.37, 2.89); (Δ 2.06; 95% CI: 0.63, 3.48), respectively]. Triclocarban was associated with a suggestive 2-day decrease in gestational age (Δ - 1.96; 95% CI: -4.11, 0.19). Bisphenol A measured at visit 1 was associated with a suggestive increase in gestational age (Δ 1.37; 95% CI: -0.05, 2.79). Triclosan was positively associated with gestational age among males, and negatively associated with gestational age among females. Methyl-, butyl- and propyl-paraben were associated with significant 0.50-0.66 decreased odds of SGA. BPS was associated with an increase in the odds of SGA at visit 3, and a suggestive increase in the odds of LGA at visit 1.

CONCLUSION

Benzophenone-3, methyl-paraben and propyl-paraben were associated with an increase in gestational age. Concentrations of triclocarban, which were much higher than reported in other populations, were associated with a suggestive decrease in gestational age. The direction of the association between triclosan and gestational age differed by infant sex. Parabens were associated with a decrease in SGA, and BPS was associated with both SGA and LGA depending on the study visit. Further studies are required to substantiate these findings.

Preterm birth in relation to the bisphenol A replacement, bisphenol S, and other phenols and parabens

INTRODUCTION

Preterm birth continues to be a significant public heath concern and is a leading cause of perinatal and infant mortality. Environmental exposures to phenols and parabens are suspected to potentially contribute to the pathology of preterm birth, yet limited human studies have characterized the extent to which these toxicants are associated with birth outcomes.

METHODS

We examined the associations between phenols, parabens, and preterm birth, within pregnant women who were recruited early in gestation into the LIFECODES cohort at Brigham and Women's Hospital in Boston, Massachusetts. Urine samples were collected at up to 4 time points in pregnancy and analyzed for phenols and parabens. We selected 130 cases of preterm birth (defined as delivery before 37 weeks gestation), and 350 random controls. We categorized preterm birth subtypes based on clinical presentation and identified 75 cases of spontaneous preterm birth (characterized by spontaneous preterm labor and/or preterm premature rupture of membranes), and 37 cases of placental preterm birth (characterized by preeclampsia and/or intrauterine growth restriction). We used multivariate logistic regression with visit specific and geometric averages of phenols and parabens to determine associations with preterm birth.

RESULTS

We observed moderate variability in urinary phenol and paraben concentrations over pregnancy with intraclass correlation coefficients ranging between 0.45 and 0.68. Regression analyses indicated mostly null associations. We observed inverse associations, notably between 2,5-dichlorophenol and overall preterm birth (adjusted odds ratio [95% confidence interval, CI]: 0.79 [0.67 - 0.94]), and this relationship was consistent by study visit. Conversely, ethyl paraben was associated with increased risk for placental preterm birth (adjusted odds ratio [95% CI]: 1.47 [1.14 - 1.91]). Bisphenol-S detection at visit 4 was associated with overall preterm birth (adjusted odds ratio [95% CI]: 2.05 [1.09, 3.89]).

CONCLUSIONS

While the findings from this study largely indicate null associations, we observed some relationships between select phenols, parabens and preterm birth, which warrants further investigation of these toxicants and birth outcomes.

Prenatal Exposure to Select Phthalates and Phenols and Associations with Fetal and Placental Weight among Male Births in the EDEN Cohort (France)

BACKGROUND

The placenta performs crucial physiological functions to ensure normal fetal development. Few epidemiological studies investigated placental weight sensitivity to phthalates and phenols.

OBJECTIVE

Our goal was to explore whether maternal exposure to select phthalates and phenols is associated with changes in placental weight at birth and in placental–to–birth weight ratio (PFR).

METHODS

Placental weight and birth weight were available for 473 mother–son pairs in the EDEN (Etude des Déterminants pré et postnatals du développement et de la santé de l'Enfant) cohort for whom 9 phenols (4 parabens, 2 dichlorophenols, triclosan, benzophenone-3, bisphenol A) and 11 phthalate metabolites were measured in spot urine samples collected between weeks 23 and 29 of gestation. We used adjusted Elastic Net penalized regression models (ENET) to select biomarkers associated with placental weight, birth weight and PFR. Unpenalized effect estimates were then obtained by fitting linear regression models simultaneously adjusted for the ENET-selected biomarkers and a priori chosen confounders.

RESULTS

The multipollutant ENET model for placental weight retained four biomarkers: triclosan and monocarboxy-isononyl phthalate (MCNP), which were negatively associated with placental weight, and benzophenone-3 and the sum of parabens, which were positively associated with this outcome. The ENET model for PFR retained two phthalate metabolites [MCNP and monocarboxy-isooctyl phthalate (MCOP)], which were negatively associated with this outcome.

DISCUSSION

The positive association between the sum of parabens and placental weight was consistent with results of a previous study among 49 male births. Our results provide preliminary evidence of possible associations between other compounds such as triclosan, benzophenone-3, MCNP, and MCOP and both placental weight and PFR. These associations were not reported in previous studies and should be seen as hypothesis generating. Studies relying on repeated assessments of exposure in prospective mother–child cohorts are needed to substantiate the plausibility of the hypotheses generated by our results. https://doi.org/10.1289/EHP3523.

Neurotoxicological effects induced by up-regulation of miR-137 following triclosan exposure to zebrafish (Danio rerio)

Triclosan (TCS) is a prevalent anthropogenic contaminant in aquatic environments and its chronic exposure can lead to a series of neurotoxic effects in zebrafish. Both qRT-PCR and W-ISH identified that TCS exposure resulted in significant up-regulation of miR-137, but downregulation of its regulatory genes (bcl11aa, MAPK6 and Runx1). These target genes are mainly associated with neurodevelopment and the MAPK signaling pathway, and showed especially high expression in the brain. After overexpression or knockdown treatments by manual intervention of miR-137, a series of abnormalities were induced, such as ventricular abnormality, bent spine, yolk cyst, closure of swim sac and venous sinus hemorrhage. The most sensitive larval toxicological endpoint from intervened miR-137 expression was impairment of the central nervous system (CNS), ventricular abnormalities and notochord curvature. Microinjection of microRNA mimics or inhibitors of miR-137 both caused zebrafish malformations. The posterior lateral line neuromasts became obscured and decreased in number in intervened miR-137 groups and TCS-exposure groups. Up-regulation of miR-137 led to more severe neurotoxic effects than its down-regulation. Behavioral observations demonstrated that both TCS exposure and miR-137 over-expression led to inhibited hearing or vision sensitivity. HE staining indicated that hearing and vision abnormalities induced by long-term TCS exposure originated from CNS injury, such as reduced glial cells and loose and hollow fiber structures. The findings of this study enhance our mechanistic understanding of neurotoxicity in aquatic animals in response to TCS exposure. These observations provide theoretical guidance for development of early intervention treatments for nervous system diseases.

Blood pressure changes during pregnancy in relation to urinary paraben, triclosan and benzophenone concentrations: A repeated measures study

Previous studies have proven the endocrine-disrupting properties and health hazards of parabens, triclosan, and benzophenones, but their relationship with blood pressure during pregnancy remains unknown. Therefore, we investigated the associations of repeated measures of urinary parabens, triclosan, and benzophenones with blood pressure during pregnancy and evaluated whether the associations were modified by fetal sex. From a prospective birth cohort in Wuhan, China, we collected urine samples from 644 pregnant women in the first, second, and third trimesters between 2014 and 2015. Five parabens, triclosan, and three benzophenones were quantified in all urine samples. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in each trimester after urine sampling. Mixed linear models were used to estimate the associations between urinary chemical levels and blood pressure during pregnancy among all pregnant women and subgroups stratified by fetal sex. In the women carrying male fetuses, urinary triclosan and selected benzophenone concentrations were associated with a slight change of SBP during pregnancy. In the women carrying female fetuses, no chemical was associated with SBP, while urinary concentration of triclosan was inversely associated with DBP, though the magnitude was small. Urinary paraben levels weren't associated with blood pressure during pregnancy. Our results suggest that triclosan and selected benzophenone exposure might be associated with blood pressure during pregnancy in a potential fetal sex-different manner. Replicated research studies in pregnant women with higher triclosan and benzophenone exposure levels are needed in the future.

Anogenital distance as a toxicological or clinical marker for fetal androgen action and risk for reproductive disorders

Male reproductive development is intricately dependent on fetal androgen action. Consequently, disrupted androgen action during fetal life can interfere with the development of the reproductive system resulting in adverse effects on reproductive function later in life. One biomarker used to evaluate fetal androgen action is the anogenital distance (AGD), the distance between the anus and the external genitalia. A short male AGD is strongly associated with genital malformations at birth and reproductive disorders in adulthood. AGD is therefore used as an effect readout in rodent toxicity studies aimed at testing compounds for endocrine activity and anti-androgenic properties, and in human epidemiological studies to correlate fetal exposure to endocrine disrupting chemicals to feminization of new-born boys. In this review, we have synthesized current data related to intrauterine exposure to xenobiotics and AGD measurements. We discuss the utility of AGD as a retrospective marker of in utero anti-androgenicity and as a predictive marker for male reproductive disorders, both with respect to human health and rodent toxicity studies. Finally, we highlight four areas that need addressing to fully evaluate AGD as a biomarker in both a regulatory and clinical setting.

Prenatal exposure to phthalates and phenols and infant endocrine-sensitive outcomes: The MIREC study

BACKGROUND

Anogenital distance (AGD) and the second to fourth finger (2D:4D) digit ratio may be early markers of in utero androgen exposure for the infant. Phthalates and phenols have been identified as endocrine disrupting chemicals.

OBJECTIVES

To study the association between prenatal exposure to phthalates, bisphenol A (BPA) and triclosan (TCS) and AGD and the 2D:4D digit ratios.

METHODS

Single spot urine samples were collected in the first trimester from the MIREC Study and analyzed for phthalates and phenols. Anogenital distance (n = 394) at birth and 2D:4D digit ratios (n = 420) at 6 months were measured in male and female infants. Associations between maternal concentrations of phenols and phthalate metabolites and these outcomes were estimated using multiple linear regression models.

RESULTS

In females, the anoclitoris distance (ACD) was negatively associated with mono-benzyl phthalate (MBzP) (β = -1.24; 95% CI -1.91, -0.57) and positively associated with mono-ethyl phthalate (MEP) (β = 0.65; 95% CI 0.12, 1.18) (masculinizing). In males, anopenile distance (APD) was positively associated with mono-n-butyl phthalate (MnBP) (β = 1.17; 95% CI 0.02, 2.32) and the molar sum of low molecular weight phthalates (ΣLMW). Female 2D:4D of the right hand was positively associated with MnBP and negatively with total BPA (masculinizing).

CONCLUSIONS

Significant associations were only observed for the long AGD metrics. Positive associations were observed between MnBP or LMW phthalates and APD in males. In females, prenatal MEP was associated with a masculinizing effect on ACD, while MBzP was associated with a feminizing effect. No significant associations were observed between prenatal phenols and AGD. Given the paucity of research on digit ratios and prenatal chemical exposures, it is difficult to say whether this metric will be a useful marker of prenatal androgen or anti-androgen exposure. Given the large number of associations examined, the statistical associations observed may have been due to Type 1 error. The inconsistencies in results between studies suggest that this issue is yet to be resolved.

The association of repeated measurements of prenatal exposure to triclosan with fetal and early-childhood growth

BACKGROUND

Triclosan (TCS) is known to possess endocrine disrupting properties and metabolize rapidly in the human body. Human data concerning repeated measurements of TCS throughout pregnancy in relation to fetal and childhood growth are sparse.

OBJECTIVES

We investigated the associations between multiple measurements of maternal urinary concentrations of TCS during pregnancy and fetal and early-childhood growth.

METHODS

The study population included 850 mother-infant pairs who participated in a prenatal cohort established between 2014 and 2015 in Wuhan. Prenatal TCS exposure was measured in a complete series of urine samples collected at the first, second and third trimesters. General linear models and generalized estimating equation models were applied to evaluate the associations of the averaged maternal urinary concentrations of TCS over trimesters and trimester-specific urinary TCS with the z-scores of estimated fetal weight, head circumference, abdominal circumference, and femur length at 16, 24, and 31 gestational weeks, weight and length at birth, and weight and height at 0.5, 1, and 2 years of age.

RESULTS

In overall infants, we did not observe any significant association of the averaged maternal urinary concentrations of TCS over trimesters with ultrasound parameters and size at birth. However, a positive association of borderline statistical significance was found between averaged prenatal TCS exposure and the third-trimester estimated fetal weight z-score in girls in sex-stratified analyses (β = 0.054, 95% CI: -0.005, 0.113, p = 0.07). Moreover, averaged prenatal TCS exposure was positively associated with 2 year-old weight z-score among total infants (β = 0.046, 95% CI: 0.005, 0.087). After stratifying by sex, the same association was observed in girls with more prominent estimation (β = 0.062, 95% CI: 0.000, 0.124), whereas the association weakened and became not significant in boys (β = 0.033, 95% CI: -0.024, 0.089). TCS exposure at 1st and 2nd-trimester were positively associated with weight z-score at 2 years, in both overall and female infants.

CONCLUSIONS

Prenatal exposure to triclosan was associated with elevated third-trimester estimated fetal weight and 2 year-old weight z-score in girls, and the early and middle stage of pregnancy may be the windows of vulnerability. Apart from these findings, we did not find strong evidence for prenatal triclosan exposure in relation to fetal and early-childhood growth.

Environmental exposure to triclosan and polycystic ovary syndrome: a cross-sectional study in China

OBJECTIVES

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy of women at reproductive age. Although the aetiology of PCOS remains unclear, potential effects of environmental endocrine-disrupting compounds on the development of PCOS have drawn increasing attention. The aim of the current study was to examine the association between triclosan (TCS) and PCOS, and explore possible mechanisms on how TCS may contribute to the development of clinical manifestations of PCOS.

DESIGN

Cross-sectional study.

SETTING

This study was conducted in one tertiary-level hospital located in Zhejiang, China.

PARTICIPANTS

A total of 674 infertile women at 18-45 years of age were recruited in 2014-2015. Participants with (n=84) and without (n=212) PCOS with urinary TCS concentration available were included in the analyses.

METHODS

Urinary TCS concentration was measured using a high-performance liquid chromatography-electrospray ionisation tandem mass spectrometry. Logistic regression model was used to examine the association between TCS and PCOS. Fractional polynomial regression models were built to fit the potential non-linear relationship between TCS concentrations and luteinising hormone (LH) and LH/follicle stimulate hormone (FSH).

RESULTS

The PCOS group had significantly higher level of TCS concentration than the non-PCOS group (the median of TCS (IQR), μg/g creatinine: 1.49 (0.68-3.80) vs 1.06 (0.52-3.02), p=0.0407). Compared with the lowest tertile, the highest tertile of TCS concentration was associated with an increased odd of PCOS (OR 2.12, 95% CI 1.12 to 3.99). After adjusting for potential confounders, the significant association remained (OR 1.99, 95% CI 1.05 to 3.79). Positive relationships were found between TCS levels and LH and LH/FSH ratio in non-PCOS participants.

CONCLUSIONS

TCS exposure at a relatively low level is associated with PCOS in Chinese women. Further epidemiological studies are needed to confirm our finding, which may have important public health implications.

Endocrine disrupting chemicals and impact on male reproductive health

Endocrine disrupting chemicals (EDCs) have been known to adversely affect the endocrine system leading to compromised functions of hormones. The presence of these compounds in everyday products such as canned food, water bottles, plastics, cosmetics, fertilizers, kid’s toys and many others goods is a greater concern for general population. The persistent and long-term use of EDCs has deleterious effects on human reproductive health by interfering with the synthesis and mechanism of action of sex hormones. Any change during the synthesis or action of the sex hormones may result in abnormal reproductive functions which includes developmental anomalies in the reproductive tract and decline in semen quality. The present paper provides an overview of the EDCs and their possible impact on male reproductive health with major focus on semen quality which leads to male infertility.