Urinary paraben concentrations among pregnant women and their matching newborn infants of Korea, and the association with oxidative stress biomarkers

Urinary paraben exposure increases the risk of a low estimated glomerular filtration rate in Taiwanese general population

BACKGROUND

The inconsistent relationship between chemical exposure and estimated glomerular filtration rate (eGFR) has been examined in only a few studies. We investigated the association between paraben exposure and indicators of renal function in a total of 361 individuals recruiting from a representative study.

METHOD

The levels of urinary parabens, including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP), were measured using UPLC-MS/MS. The association between paraben exposure and indices of renal function was assessed using multiple logistic regression and Bayesian Kernel Machine Regression (BKMR).

RESULTS

The median levels of urinary parabens in the adult group were significantly higher than those in the minor group, that is, 397 vs. 148 ng/mL for MeP, 38.8 vs. 13.6 ng/mL for EtP, 117 vs. 57.7 ng/mL for PrP, and 6.61 vs. 2.79 ng/mL for BuP (all P < 0.001). In the adult group, multivariate regression models confirmed a positive association between the albumin-to-creatinine ratio and urinary MeP (β = 0.580) and a positive association of BUN (β = 0.061) and a negative association of eGFR (β = -0.051) with urinary EtP (all P < 0.001). In the adult group, compared with the lowest tertile group, the adjusted odds ratio in the third tertile (T3) of urinary EtP levels indicated a 3.08 times increased risk of eGFR abnormalities, followed by the second tertile (T2) with a 2.63 times increased risk. The generalized additive model (GAM) and BKMR models showed a non-linear correlation between urinary EtP levels and early CKD, as well as reduced eGFR. We observed a significant positive cumulative effect of urinary paraben on eGFR, and a significant positive single exposure effect of urinary EtP with eGFR abnormality.

CONCLUSION

We found a significant association between exposure to EtP and an increased risk of high BUN levels and decreased eGFR.

Environmental phenol exposures in 6- to 12-week-old infants: The Infant Feeding and Early Development (IFED) study

BACKGROUND

Exposure to phenols, endocrine-disrupting chemicals used in personal care and consumer products, is widespread. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period. We aimed to describe distributions and predictors of urinary phenol concentrations among U.S. infants ages 6-12 weeks.

METHODS

The Infant Feeding and Early Development (IFED) study is a prospective cohort study of healthy term infants enrolled during 2010-2013 in the Philadelphia region. We measured concentrations of seven phenols in 352 urine samples collected during the 6- or 8- and/or 12-week study visits from 199 infants. We used linear mixed models to estimate associations of maternal, sociodemographic, infant, and sample characteristics with natural-log transformed, creatinine-standardized phenol concentrations and present results as mean percent change from the reference level.

RESULTS

Median concentrations (μg/L) were 311 for methylparaben, 10.3 for propylparaben, 3.6 for benzophenone-3, 2.1 for triclosan, 1.0 for 2,5-dichlorophenol, 0.7 for BPA, and 0.3 for 2,4-dichlorophenol. Geometric mean methylparaben concentrations were approximately 10 times higher than published estimates for U.S. children ages 3-5 and 6-11 years, while propylparaben concentrations were 3-4 times higher. Infants of Black mothers had higher concentrations of BPA (83%), methylparaben (121%), propylparaben (218%), and 2,5-dichorophenol (287%) and lower concentrations of benzophenone-3 (-77%) and triclosan (-53%) than infants of White mothers. Triclosan concentrations were higher in breastfed infants (176%) and lower in infants whose mothers had a high school education or less (-62%). Phenol concentrations were generally higher in summer samples.

CONCLUSIONS

Widespread exposure to select environmental phenols among this cohort of healthy U.S. infants, including much higher paraben concentrations compared to those reported for U.S. children, supports the importance of expanding population-based biomonitoring programs to infants and toddlers. Future investigation of exposure sources is warranted to identify opportunities to minimize exposures during these sensitive periods of development.

A study on assessing the toxic effects of ethyl paraben on rohu (Labeo rohita) using different biomarkers; hemato-biochemical assays, histology, oxidant and antioxidant activity and genotoxicity

Parabens are being used as preservatives due to their antifungal and antimicrobial effects. They are emerging as aquatic pollutants due to their excessive use in many products. The purpose of this study was to determine the toxic effect of ethyl paraben (C9H10O3) on the hematobiochemical, histological, oxidative, and anti-oxidant enzymatic and non-enzymatic activity; the study also evaluates the potential of ethyl paraben to cause genotoxicity in Rohu Labeo rohita. A number of 15 fish with an average weight of 35.45±1.34g were placed in each group and exposed to ethyl paraben for 21 days. Three different concentrations of ethyl paraben, i.e., T1 (2000μg/L), T2 (4000 μg/L), andT3 (6000 μg/L) on which fish were exposed as compared to the control T0 (0.00 μg/L). Blood was used for hematobiochemical and comet assay. Gills, kidneys, and liver were removed for histological alterations. The results showed a significant rise in all hemato-biochemical parameters such as RBCs, WBCs, PLT count, blood sugar, albumin, globulin, and cholesterol. An increase in aspartate aminotransferase (AST) and alanine transaminase (ALT) levels directed the hepatocytic damage. Histological alterations in the liver, gills and kidneys of fish were found. Ethylparaben induces oxidative stress by suppressing antioxidant enzyme activity such as SOD, GSH, CAT and POD. Based on the comet assay, DNA damage was also observed in blood cells, resulting in genotoxicity. Findings from the present study indicate that ethyl paraben induces hemato-biochemical alterations, tissue damage, oxidative stress, and genotoxicity.

Distribution of parabens and 4-HB in human blood

Human blood has been commonly and routinely analyzed to determine internal human exposure to parabens. However, data on the occurrence of parabens and their common metabolite, p-hydroxybenzoic acid (4-HB), in different human blood matrixes is still limited. In this study, 139 pairs of serum and whole blood samples were collected from Chinese adults, and then analyzed them for 5 parabens and 4-HB. Methylparaben (MeP) and propylparaben (PrP) were consistently the predominant parabens in human serum (mean 2.3 and 2.1 ng/mL, respectively) and whole blood (1.9 and 1.3 ng/mL, respectively). Mean concentrations of 4-HB in human serum and whole blood were 7.7 and 12 ng/mL, respectively. Concentrations of parabens, except benzylparaben (BzP), and 4-HB in human serum were significantly (p < 0.01) correlated with that in whole blood. Distribution pattern of parabens and 4-HB in human blood was evaluated, for the first time, based on their partitioning between human serum and whole blood (Kp). Mean Kp values of parabens, except BzP, increased with the alkyl chain length from 0.83 to 1.6. BzP (mean 1.4) had a comparable mean Kp value to PrP (mean 1.4). Among target analytes, 4-HB had the lowest mean Kp value (0.75). These data are important to select appropriate blood matrixes for conducting human exposure assessment and epidemiological studies on parabens.

Repeated measurements and mixture effects of urinary bisphenols, parabens, polycyclic aromatic hydrocarbons, and other chemicals on biomarkers of oxidative stress in pre- and postpartum women

The association between oxidative stress and exposure to bisphenols, parabens, phenols, polycyclic aromatic hydrocarbons (PAH), and volatile organic compounds (VOCs) has been investigated by many in vitro and in vivo studies. However, most of these findings are based on cross-sectional studies, as a result of which the combined effects of these compounds have been rarely analyzed. In this study, our objective was to assess urinary bisphenols, parabens, PAHs, and VOCs, in relation to oxidative stress during pre-and postpartum periods, analyze the association between these chemicals and oxidative stress via repeated measurements using a linear mixed model (LMM), and evaluate the combined effects exerted by these chemicals on oxidative stress using Bayesian Kernel Machine Regression (BKMR). A total 529 urine samples were collected from 242 pregnant women during the 1st and 2nd trimesters, as well as postpartum follow-ups. Three bisphenols, four parabens, benzopheone-3 (BP-3), triclosan (TCS), four PAHs, two VOCs, and 3- phenoxy-benzoic acid (3-PBA) were analyzed. We also measured 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA), which serve as oxidative stress biomarkers in maternal urine samples. During this period, 8-OHdG decreased steadily, whereas MDA increased during pregnancy and decreased after childbirth. LMM indicated that Bisphenol A, Prophyl-paraben, BP-3, and 1-hydroxypyrene (1-OHP) showed a significant association with increased MDA levels. The BKMR models revealed that the mixture effect exerted by these 16 chemicals had changed MDA levels, which indicate oxidative stress, and that both Butyl Paraben (BP) and 1-hydroxypyrene (1-OHP) had contributed to such oxidative stress. Mixtures of each subgroup (bisphenols, parabens, and PAHs) were associated with increased MDA levels. These findings suggest that exposure to some phenols and PAHs during pre- and post-partum stages may cause oxidative stress, and that exposure to these chemicals should be minimized during this period.

Human exposure to methyl and butyl parabens and their transformation products in settled dust collected from urban, semi-urban, rural, and tribal settlements in a tropical environment

The present study involved monitoring the distribution of two widely consumed parabens (methyl paraben (MeP) and butyl paraben (BuP)) and their transformation products in indoor dust from different categories of settlement (urban, semi-urban, rural, and tribal homes). The results revealed a prevalent occurrence of parabens in all the settlement categories. A non-normal distribution pattern for MeP and BuP levels across the sampling sites was noted. While comparing the residence time of parabens in dust samples, it was found that the half-lives of the analytes were greater in the dust from urban (MeP t1/2: 47.510 h; BuP t1/2: 22.354 h) and rural (MeP t1/2: 27.725 h and BuP t1/2: 31.500 h) areas. The presence of paraben metabolites, such as hydroxy methylparaben (OH-MeP), para hydroxy benzoic acid (p-HBA), and benzoic acid (BA) in dust samples supports their transformation within indoor spaces. The average daily intake of parabens through dust ingestion and dermal absorption by children was higher than adults. BuP was the prime contributor (>85%) to the total estradiol equivalency quotient (tEEQ) in all the settlement categories.

Parabens as environmental contaminants of aquatic systems affecting water quality and microbial dynamics

Among different pollutants of emerging concern, parabens have gained rising interest due to their widespread detection in water sources worldwide. This occurs because parabens are used in personal care products, pharmaceuticals, and food, in which residues are generated and released into aquatic environments. The regulation of the use of parabens varies across different geographic regions, resulting in diverse concentrations observed globally. Concentrations of parabens exceeding 100 μg/L have been found in wastewater treatment plants and surface waters while drinking water (DW) sources typically exhibit concentrations below 6 μg/L. Despite their low levels, the presence of parabens in DW is a potential exposure route for humans, raising concerns for both human health and environmental microbiota. Although a few studies have reported alterations in the functions and characteristics of microbial communities following exposure to emerging contaminants, the impact of the exposure to parabens by microbial communities, particularly biofilm colonizers, remains largely understudied. This review gathers the most recent information on the occurrence of parabens in water sources, as well as their effects on human health and aquatic organisms. The interactions of parabens with microbial communities are reviewed for the first time, filling the knowledge gaps on the effects of paraben exposure on microbial ecosystems and their impact on disinfection tolerance and antimicrobial resistance, with potential implications for public health.

Effect of Butyl Paraben on Oxidative Stress in the Liver of Mauremys sinensis

Butyl paraben (BuP) has been widely used as a preservative in the cosmetics, food, and medicine industries. Recently, it has become a new pollutant and has attracted much attention. In order to evaluate the toxic effect of BuP on aquatic animals, Chinese striped-neck turtles (Mauremys sinensis) were exposed to BuP solutions with different concentrations of 0, 5, 50, 500, and 5000 µg/L for 20 weeks. The results showed that with an increase in BuP concentration, the activity of antioxidant enzymes (SOD, CAT and GSH-PX) in liver decreased. The expression of key genes in the Nrf2-Keap1 signal pathways first increased and then decreased, while the expression of the HSP70 and HSP90 genes increased. In addition, the liver had an inflammatory reaction. The expression of the BAFF and IL-6 genes increased and then decreased with an increase in BuP concentration, while the expression of P50 and P65 increased significantly. Oxidative stress induced apoptosis, and the expression of pro-apoptosis genes (BAX, cytc, Caspase3 and Caspase9) increased, while the expression of the anti-apoptosis gene Bcl2 decreased. The results provide an important reference for the comprehensive ecological and health risk assessment of environmental BuP.

Exposure to parabens and dysglycemia: Insights from a Chinese population

BACKGROUND

Parabens, a widely exposed environmental endocrine disruptor, were reported to disturb glucose metabolism through various pathways in animal models, but epidemiologic studies are limited. Therefore, this study aimed to investigate the plasma parabens level in rural populations and their effects of single and mixed paraben exposure on T2DM based on the Henan Rural Cohort.

METHODS

A total of 1713 participants (880 T2DM and 833 controls) from the Henan Rural Cohort Study were included in this case-control study. Generalized linear regression models were performed to assess the single and joint effects of parabens on T2DM and glucose metabolism indicators. In addition, the dose-response relationship of plasma parabens with T2DM and glucose metabolism indicators were explored by the restricted cubic splines. Bayesian kernel machine regression (BKMR) and quantile g-computation models were utilized to assess overall associations of paraben mixtures with T2DM and glucose metabolism indicators.

RESULTS

Σparabens and methylparaben (MeP) exposure significantly increased the risk of T2DM (P < 0.01). However, ethylparaben (EtP) and butylparaben (BuP) were negatively related to T2DM (P < 0.01). Notably, non-linear relationships of EtP and BuP with T2DM were observed. When the level of EtP or BuP was above the inflection point observed in dose-response curve, the ORs and 95% CIs were 1.453 (1.252, 1.686) and 1.982 (1.444, 2.721), respectively. Moreover, the result of quantile g-computation also showed that exposure to high concentration of parabens mixture was positively related to the risk of T2DM. BKMR model indicated that parabens mixture was associated with glycometabolism following a U-shape and parabens mixture increased the risk of dysglycemia when all parabens concentrations were at or above their 55th percentile compared with the median.

CONCLUSION

MeP or paraben mixture exposure levels showed a linear positive association with risk of T2DM. EtP and BuP were nonlinearly associated with glucose metabolism and moderate-high exposure contributed to T2DM.

Environmental exposure to paraben and its association with blood pressure: A cross-sectional study in China

Parabens (PBs) are the most widely used preservatives. Recent epidemiological studies have indicated that environmental exposure to parabens has adverse health effects, such as increased metabolic diseases risk. However, limited information is available on the cardiovascular effect of paraben exposure. Hence, we conducted a cross-sectional study investigating the associations between exposure to parabens with high blood pressure risk and blood pressure levels among the general Chinese population. In this study, we enrolled 1405 individuals from a medical center in Wuhan, China. Urinary methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP) and butylparaben (BuP) concentrations were determined. Multivariable logistic and linear regression models were applied to analyze the associations between urinary parabens and high blood pressure risk and blood pressure level changes. Bayesian kernel machine regression (BKMR) models were applied to estimate the combined effect of the four parabens. Compared with the first quartile group, participants with the fourth quartile of EtP, PrP, and ∑parabens (∑PBs) concentrations had a 2.10-fold (95% CI: 1.40, 3.00), 1.83-fold (95% CI: 1.27, 2.62) and 1.84-fold (95% CI: 1.27, 2.65) increased the risk of hypertension, respectively. High urinary EtP, PrP, and ∑PBs levels were found to increase the levels of systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), and mid-blood pressure (MBP). BKMR models indicated the overall effects of the paraben mixture were significantly associated with high blood pressure risk and blood pressure level changes. Furthermore, after stratification by sex, the associations of EtP exposure and blood pressure levels were more pronounced in males. Our results suggest that environmental exposure to parabens might elevate blood pressure levels and increase the risk of high blood pressure.

Rhus tripartite methanolic extract alleviates propylparaben-induced reproductive toxicity via anti-inflammatory, antioxidant, 5-α reductase in male rats

Evidence showed that herbal medicine could be beneficial for protection against diseases that may be exist in consequence of exposure to environmental toxicants. Propylparaben (PrP) is used as preservative in food, pharmaceuticals, and cosmetics. It is classified as one of endocrine disruptive chemicals (EDCs). This study evaluated the protective effect of Rhus tripartita methanolic extract (RTME) against reproductive toxicity induced by PrP in male rats. A total of 60 Wister albino rats were divided into four groups (15 rats for each group). Group I (control): rats received the vehicle (DMSO), group II: normal rats received RTME (10 mg/kg/day), group III: rats received PrP (10 mg/kg/day), and group IV: rats received PrP (10 mg/kg/day) and RTME (10 mg/kg/day) for 4 weeks. At the end of experiment, levels of testosterone, dihydrotestosterone (DHT), and 5α-reductase were analyzed in sera. Data obtained showed a significant reduction in the levels of testosterone, dihydrotestosterone (DHT), and 5α- reductase in rats given PrP versus control (p < 0.001) and RTME treatment improved these parameters but not returned to normal. Data obtained showed a significant elevation in levels of IL-6 and TNF-α in the testis of rats given PrP versus control (p < 0.001), these inflammatory mediators were significant reduced in rats treated with RTME compared with untreated rats (p < 0.001). There was a positive correlation between level of DHT and antioxidant enzymes activities (r = 0.56). A significant elevation in the levels of MDA with reduction in the activities of GST, GSPx, SOD, and catalase (p < 0.001) in rat testicular tissues of PrP group versus control (p < 0.001) was found. Treatment with RTME significantly reduced the levels of MDA and enhanced activities of GST, GSPx, SOD, and catalase (p < 0.001) compared to untreated group (p < 0.001). In conclusion, the active ingredient components of RTME abrogate the toxicity of PrP by exhibiting antioxidative and anti-inflammatory effects, enhancing 5-α reductase with improved hormonal status against PrP- induced testicular damage. Toxicity of propylparaben, and effect of Rhus tripartita methanolic extract.

Endocrine Disruption of Propylparaben in the Male Mosquitofish (Gambusia affinis): Tissue Injuries and Abnormal Gene Expressions of Hypothalamic-Pituitary-Gonadal-Liver Axis

Propylparaben (PrP) is a widely used preservative that is constantly detected in aquatic environments and poses a potential threat to aquatic ecosystems. In the present work, adult male mosquitofish were acutely (4d) and chronically (32d) exposed to environmentally and humanly realistic concentrations of PrP (0, 0.15, 6.00 and 240 μg/L), aimed to investigate the toxic effects, endocrine disruption and possible mechanisms of PrP. Histological analysis showed time- and dose-dependent manners in the morphological injuries of brain, liver and testes. Histopathological alterations in the liver were found in 4d and severe damage was identified in 32d, including hepatic sinus dilatation, cytoplasmic vacuolation, cytolysis and nuclear aggregation. Tissue impairments in the brain and testes were detected in 32d; cell cavitation, cytomorphosis and blurred cell boundaries appeared in the brain, while the testes lesions contained spermatogenic cell lesion, decreased mature seminal vesicle, sperm cells gathering, seminiferous tubules disorder and dilated intercellular space. Furthermore, delayed spermatogenesis had occurred. The transcriptional changes of 19 genes along the hypothalamus-pituitary-gonadal-liver (HPGL) axis were investigated across the three organs. The disrupted expression of genes such as Ers, Ars, Vtgs, cyp19a, star, hsd3b, hsd17b3 and shh indicated the possible abnormal steroidogenesis, estrogenic or antiandrogen effects of PrP. Overall, the present results provided evidences for the toxigenicity and endocrine disruptive effects on the male mosquitofish of chronic PrP exposure, which highlights the need for more investigations of its potential health risks.

Maternal paraben exposure and intra-pair thyroid-stimulating hormone difference in twin neonates

Thyroid hormones are essential for fetal growth and neurodevelopment. The recent frequent use of parabens has raised concerns about their endocrine-disrupting potential. However, the effects of maternal paraben exposure on neonatal thyroid hormone levels are still largely unknown. In our study, a co-twin control design was employed to analyze the relationships between maternal paraben exposure and neonatal thyroid-stimulating hormone (TSH) difference. We collected information from 252 mother-twin pairs from a twin birth cohort in Wuhan, China. Concentrations of six parabens were measured in maternal urine samples collected at < 16, 16-28, and > 28 weeks of gestation. Data of neonatal TSH levels were retrieved from medical records. Multiple informant models were applied to explore the time-specific relationships between paraben exposure and intra-twin TSH difference and to determine the susceptible window of exposure. We found that maternal urinary methyl paraben (MeP) during early pregnancy was positively associated with intra-twin TSH difference (%change = 5.96 %; 95 % confidant interval (CI): 0.04 %, 12.2 %). However, no significant differences were observed for exposure to ethyl paraben (EtP) and propyl paraben (PrP), and the associations between parabens and intra-twin TSH difference did not differ materially across pregnancy. Further, a stratified analysis based on twin zygosity and chorionicity and sex types indicated that the positive association between early pregnancy MeP exposure and intra-twin TSH difference was significant in monochorionic diamniotic (MCDA) twins of female-female fetuses and dichorionic diamniotic (DCDA) twins of opposite-sex. The prospective twin study provides first evidence that MeP exposure in early pregnancy was associated with an increased TSH difference in twin neonates, especially in female fetuses.

Impact of Paraben Exposure on Adiposity-Related Measures: An Updated Literature Review of Population-Based Studies

Parabens are alkyl esters of p-hydroxybenzoic acid that are commonly used in pharmaceutical and cosmetic products. Humans are exposed to parabens when they use these products and through diet. There are growing concerns that paraben exposure can adversely impact human health. The endocrine-disrupting and obesogenic properties of parabens have been observed in animal studies and in vitro, prompting the increase in population-based studies of paraben exposure and adiposity-related endpoints. In this review, we summarize epidemiological studies published between 2017 and 2022 that examined paraben exposure in utero, between birth and adolescence, and in adulthood, in relation to adiposity-related measures. Overall, these studies provide some evidence that suggests that paraben exposure, especially during critical development windows, is associated with adiposity-related measures. However, we have noted several limitations in these studies, including the predominance of cross-sectional studies, inconsistent sample collection procedures, and small sample sizes, which should be addressed in future studies.

Urinary paraben concentrations of adult women by fasting status: Comparison between Korea and the United States

Personal care products (PCPs) are considered as a major source of paraben exposure; however, the dietary contribution is not well known. We compared the urinary levels of methyl-, ethyl-, and propyl-paraben (MeP, EtP, and PrP), and investigated their associations with fasting status and contacts with other potential exposure sources among Korea and the US adult women. A group of fasting, non-pregnant adult women (n = 469) was recruited from Seoul, Ansan/Incheon, and Jeju, Korea in 2015-2016, and their urine was measured for parabens. Non-fasting Korean women of matching age (25-45 years) were chosen from the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (n = 579). For the US women, both fasting (n = 154) and non-fasting (n = 201) females were chosen from the NHANES 2015-2016 participants. In fasting Korean women, the urinary MeP, EtP, and PrP concentrations (median) were measured at 47.30, 17.90, and 2.30 ng/mL, respectively. Urinary EtP and PrP levels in fasting Korean women were significantly lower than those in non-fasting women (EtP and PrP median of 26.40 and 3.57 ng/mL). On average, the difference in urinary EtP levels by fasting status was greater among the highly exposed groups. In the US population, EtP levels were significantly lower (median ranged 1.55-1.80 ng/mL depending on fasting status), but MeP levels were higher (67.90-84.35 ng/mL) than those of the Korean population. When only fasting women were considered, the median EtP levels of Korean women were 11.5-fold greater than those of US women, suggesting that the non-dietary contributions of EtP exposure could not be ignored among Korean women. Regardless of fasting status, MeP and PrP were significantly correlated, and their urinary levels in fasting Korean women were correlated with the use of several personal care products. The major dietary and non-dietary sources that may explain EtP exposure in Korean women warrant further investigation.

Comprehensive assessment of estrogenic activities of parabens by in silico approach and in vitro assays

Parabens are ubiquitous pollutants in the environment and humans due to their wide applications in food, pharmaceuticals, and personal care products. Although the estrogenic activity of some parabens has been confirmed, the underlying mechanisms and the structure-estrogenic activity relationship are still largely unclear. Here, we systematically used in silico and in vitro approaches to investigate the estrogenic potency of typical parabens, including methyl-, ethyl-, propyl-, iso-propyl-, butyl-, iso-butyl- and benzyl-paraben. Molecular dynamics simulations and binding free energy calculations were combined to investigate the atomic-level mechanism of paraben binding to estrogen receptors (ERs). Computational analysis showed that ER were the targets of tested parabens and kept a stable agonist conformation. The calculated total binding free energies suggested that van der Waals interactions were the major driving forces for paraben-ER interaction and correlated with the structure of paraben side chains. In in vitro assays, paraben with an aromatic side chain, benzyl-paraben, showed the strongest estrogenic activity at 0.01 μM and the EC₅₀ at 0.796 ± 0.307 μM, on par with levels commonly detected in human organs. Among tested parabens with an alkyl side chain, the estrogenicity increased as the side chain length increased from 1 to 4, but no significant difference appeared between parabens with isomeric alkyl side chains (propyl- vs isopropyl and butyl- vs iso-butylparaben). The estrogenic activity of parabens was significantly related to the calculated binding energies (R² = 0.94, p = 0.0012), depending on the side chains of parabens. Our findings provide a significant mechanism for parabens to disrupt estrogenic function and considerations for structural optimization from the perspective of environmental protection.

Paraben exposures and their interactions with ESR1/2 genetic polymorphisms on hypertension

The widely used paraben preservatives have been frequently detected in human urine, and shown to disrupt the endocrine system. Recently, several epidemiologic studies have investigated the associations between paraben exposures and hypertension risk, but findings are inconsistent. Genetic susceptibility variation may contribute to the conflicting results. This study aimed to explore the associations of paraben exposures and their interactions with estrogen receptor genes 1 and 2 (ESR1 and ESR2) polymorphisms with hypertension. We conducted a hospital-based case-control study involving 396 hypertension cases and 396 controls in Wuhan, China. The urinary paraben concentrations were determined using a liquid chromatography-quadrupole time of flight mass spectrometer. The genotyping of ESR1 and ESR2 was performed using the Applied Biosystems 3730 XL sequencer. Multivariable logistic regression models were applied to examine the associations between urinary paraben concentrations and hypertension risk. Gene-environment interactions were estimated on both multiplicative and additive scales. The results showed that urinary ethylparaben (EtP), propylparaben (PrP), and ∑parabens (∑PBs) levels were positively associated with the risk of hypertension (P_trend<0.05). Compared with their reference groups, subjects in the highest tertile of EtP, PrP, and ∑PBs had a 4.05-fold (95% CI: 2.56, 6.41), 2.72-fold (95% CI: 1.76, 4.20), and 1.60-fold (95% CI: 1.08, 2.36) increased risk of hypertension, respectively. When stratified by sex, the hypertensive effect of EtP was more pronounced in males (P_interaction = 0.012). Furthermore, interaction analysis showed that PrP exposure interacted with ESR1 rs2234693 polymorphism on hypertension risk, with the significance of multiplicative (P_interaction = 0.043) and additive (RERI = 1.27, AP = 0.52). Our results suggested that paraben exposure was positively related to hypertension risk, and that ESR1 rs2234693 polymorphism might modify the parabens exposure-related hypertensive effect.

Association between parabens concentrations in human amniotic fluid and the offspring birth size: A Sub-study of the PERSIAN birth cohort

OBJECTIVE

Parabens are extensively used, and cause widespread exposure of the general population including pregnant women and developing fetuses to these pollutants. In this study, we aimed to investigate the association between the maternal exposure of parabens to study their transfer passed through the placental barrier to amniotic fluid; the second objective was to determine the association of paraben concentration in the amniotic fluid with the offspring birth size.

METHODS

This cross-sectional study was conducted from June 2019 to March 2021 in Isfahan, Iran. Samples of amniotic fluid were collected as set from 128 pregnant women at Cesarean section. The amniotic fluid concentrations of four parabens including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were determined using gas chromatography tandem mass spectroscopy (GC-Mass).

RESULTS

The pointed parabens were extracted from yielded clear supernatant using a dispersive liquid-liquid microextraction (DLLME) method. Four paraben derivatives including MP (normal: 0.68 ± 0.7; overweight: 1.40 ± 1.76; obese: 0.30 ± 0.26; p-value: 0.275), EP (normal: 0.14 ± 0.09; overweight: 0.72 ± 0.72; obese: 0.38 ± 0.05; p-value: 0.434), PP (normal: 0.05 ± 0.05; overweight: 0.06 ± 0.06; obese: 0.20 ± 0.17; p-value: 0.770), and BP (normal: 2.89 ± 1.80; overweight: 3.89 ± 6.48; obese: 5.80 ± 7.56; p-value: 0.341) were simultaneously detected in samples of maternal amniotic fluid using GC-MS. In 92.2% (n = 118) of pregnant women, the paraben derivatives (MP, EP, PP, BP) were detected. We found that considerable levels of MP, EP, PP, and BP existed in 22.6% (n = 29), 21.9% (n = 28), 29.7% (n = 38), and 85.2% (n = 109) of samples, respectively. In addition, the correlation between paraben concentrations in amniotic fluid and birth size was investigated. The results showed that an inverse significant association between MP and head circumference, chest, hip, and arm circumference. While a positive correlation between MP and height of newborn was observed. Similar correlations were observed for EP and weight, height, head circumference, chest, hip, and arm.

CONCLUSION

The current study indicated that parabens have been detected in amniotic fluid samples and a strong/possible correlation between exposure of pregnant women to parabens and the birth size of newborns.

Prenatal exposure to parabens in association with cord serum adipokine levels and offspring size at birth

BACKGROUND

Paraben exposure is linked to the release of adipokine such as leptin and adiponectin, and both paraben and adipokine may affect fetal growth. The present study aimed to explore the associations among maternal paraben exposure, adipokine level and offspring size.

METHODS

942 mother-newborn pairs from the Sheyang Mini Birth Cohort Study (SMBCS) were enrolled. Data of birth weight, length, head circumference and ponderal index (PI) were obtained from medical records. Maternal urinary parabens were determined by gas chromatography tandem mass spectrometry. Cord serum leptin and adiponectin were measured using ELISA assay. Generalized linear regression was applied to explore the associations among parabens, adipokines and offspring size.

RESULTS

The median levels of leptin and adiponectin were 13.13 μg/L and 161.82 μg/mL. Benzylparaben level was positively associated with leptin (regression coefficient (β) = 0.06, 95% confidence interval (CI): 0.03-0.09; p < 0.01). Leptin level was positively associated with neonatal weight (β = 84.11, 95% CI: 63.22-105.01; p < 0.01), length (β = 0.25, 95% CI: 0.14-0.37; p < 0.01), head circumference (β = 0.15, 95% CI: 0.07-0.22; p < 0.01) and PI (β = 0.23, 95% CI: 0.08-0.39; p < 0.01). Adiponectin was positively associated with neonatal weight (β = 75.94, 95% CI: 29.65-122.23; p < 0.01) and PI (β = 0.43, 95% CI: 0.09-0.77; p = 0.01). Urinary propylparaben concentration (β = -0.10, 95% CI: -0.17 to -0.02; p = 0.01) was negatively associated with head circumference. Sex-stratified analyses indicated the negative association of propylparaben and head circumference was only remained in male neonates.

CONCLUSIONS

Prenatal paraben exposure might affect cord serum leptin levels. Both paraben and adipokine levels may affect fetal growth, and sex-specific differences may exist.

Urinary paraben derivatives in pregnant women at three trimesters: Variability, predictors, and association with oxidative stress biomarkers

Exposure to parabens has been shown to increase oxidative stress, which has a vital impact on the development of numerous diseases. However, few studies reported the effects of the paraben derivatives on oxidative stress, particularly among pregnant women. This study, using repeated measurements, aimed to understand the exposure profiles of urinary paraben derivative concentrations and their relationships with oxidative stress biomarkers (OSBs). A total of 861 pregnant women, who provided spot urine samples at three trimesters, were included, and 2583 urine samples were used to measure four paraben derivatives [p-hydroxybenzoic acid (p-HB), 3,4-dihydroxybenzoic acid (3,4-DHB), methyl protocatechuate, and ethyl protocatechuate], four parabens (methyl, ethyl, propyl, and butyl), and three OSBs [8-hydroxy-2'-deoxyguanosine (for DNA), 8-hydroxyguanosine (for RNA), and 4-hydroxy nonenal mercapturic acid (for lipid)]. Pregnant women were extensively exposed to parabens and paraben derivatives with detection frequencies (DFs) of 86.1%-100%, except for butylparaben with a DF of 14.9%. p-HB and 3,4-DHB had relatively high urinary concentrations (specific gravity-adjusted median values: 1394 and 74.5 ng/mL, respectively). Low reproducibility in paraben derivatives was found across the three trimesters. Sampling season, pre-pregnancy body mass index, and infant sex were predictors of some paraben derivatives/parabens. Linear mixed model analyses showed that all target compounds (if DF > 50%) were associated with increases in all the selected OSBs, where the percent change in OSBs with an interquartile range increase in paraben concentration ranged from 9.85% to 24.7%, while those in paraben derivative concentration ranged from 13.8% to 72.1%. Weighted quantile sum model showed that joint exposure was significantly associated with increased OSBs, and paraben derivatives were stronger contributors to OSBs compared with parabens. Overall, urinary paraben derivatives were associated with increased oxidative stress of nucleic acids and lipid in pregnant women.

Chronic exposure to propylparaben at the humanly relevant dose triggers ovarian aging in adult mice

Parabens, a type of endocrine-disrupting chemicals, are widely used as antibacterial preservatives in food and cosmetics in daily life. Paraben exposure has gained particular attention in the past decades, owing to its harmful effects on reproductive function. Whether low-dose paraben exposure may cause ovarian damage has been ignored recently. Here, we investigated the effects of chronic low-dose propylparaben (PrPB) exposure on ovarian function. Female C57BL/6J mice were exposed to PrPB at a humanly relevant dose for 8 months. Our results showed that chronic exposure to PrPB at a humanly relevant dose significantly altered the estrus cycle, hormone levels, and ovarian reserve, accelerating ovarian aging in adult mice. These effects are accompanied by oxidative stress enrichment, leading to steroidogenesis dysfunction and acceleration of primordial follicle recruitment. Notably, melatonin supplementation has been shown to protect against PrPB-induced steroidogenesis dysfunction in granulosa cells. Here, we report that daily chronic PrPB exposure may contribute to ovarian aging by altering oxidative stress-mediated JNK and PI3K-AKT signaling regulation, and that melatonin may serve as a pharmaceutical candidate for PrPB-associated ovarian dysfunction.

Urinary parabens and their derivatives associated with oxidative stress biomarkers in children from South and Central China: Repeated measures

Previous studies implied that elevated exposure to parabens may result in increased oxidative stress. However, the association between exposure to paraben derivatives and oxidative stress biomarkers in children has been rarely studied. This study examined the associations between exposure to paraben derivatives and oxidative stress biomarkers in Chinese children. Nine targeted compounds of parabens and their derivatives including methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), butyl paraben (BuP), p-hydrox4ybenzoic acid (p-HB), 3,4-dihydroxy benzoic acid (3,4-DHB), benzoic acid, methyl 3,4-dihydroxybenzoate (rOH-MeP), and ethyl 3,4-dihydroxybenzoate (rOH-EtP) were detected in urine collected from 139 children from South and Central China. Additionally, 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), and 4-hydroxy-2-nonenal mercapturic acid (HNE-MA) were measured as oxidative stress biomarkers. All targeted compounds (except for BuP) were frequently detected in urine (detection frequencies ranged 80.8%-100%). Linear mixed effects model revealed that all targeted compounds (with detection frequencies >50%), except for EtP, were significantly associated with an increase in 8-OHdG. rOH-EtP was found to be significantly associated with 8-OHG (β = 0.12; 95% confidence interval [95% CI]: 0.08, 0.16) positively. In addition, PrP and benzoic acid were associated with elevated levels of HNE-MA. Weighted quantile sum regression revealed that co-exposure to the targeted compounds was positively associated with 8-OHdG (β = 0.17; 95% CI: 0.12, 0.22), 8-OHG (β = 0.14; 95% CI: 0.10, 0.18), and HNE-MA (β = 0.43; 95% CI: 0.27, 0.59); rOH-EtP and benzoic acid were the major contributors for the combined effects on oxidative stress of nucleic acids and lipid, respectively. Our findings provide new evidence for the effects of exposure to paraben derivatives on nucleic acid oxidative damage and lipid peroxidation in children.

Diurnal Variation in Biomarkers of Exposure to Endocrine-Disrupting Chemicals and Their Association with Oxidative Damage in Norwegian Adults: The EuroMix Study

Much evidence on the adverse health effects of endocrine-disrupting chemicals (EDCs) has accumulated during recent decades. EDCs are commonly found in various foods and personal care products (PCP). Data documenting a diurnally varying EDC metabolism in humans is scarce. This study examined (i) the time-of-day effect on the diurnal magnitude and variance of urinary biomarkers of exposure to EDCs, and (ii) the association between EDC exposures and oxidative damage in a Norwegian adult subpopulation. This was a cross-sectional panel study using biobanked samples from the EuroMix project. During a typical weekday, participants were asked to collect all day’s urine voids and record dietary and PCP habitual uses in a diary. Collected time stamps of urine voids were classified into three distinct periods in the day (morning 6 a.m.−12 p.m., mid-day 12 p.m.−6 p.m., evening 6 p.m.−6 a.m.). Questionnaires regarding demographic characteristics, personal care product usage, and dietary habits were completed. Urinary levels of EDCs (phthalates, parabens, and bisphenols) were measured using mass spectrometry and adjusted for urinary volume using specific gravity. Urinary 4-hydroxynonenal (4HNE), a lipid peroxidation marker, was measured using an immunoassay kit. Linear mixed-effect models identified EDCs under the influence of a diurnal variation effect that was adjusted for dietary habits and PCP use and examined associations between EDC and 4HNE. p-values were FDR-adjusted. Most phthalates appeared to be diurnally varying with higher urinary levels towards the evening (q < 0.001) than those measured during mid-day; this strong diurnal variation effect was not present for parabens and bisphenols. Significant (q < 0.001) positive associations were observed between all phthalates, parabens, and bisphenols (except bisphenol S) and 4HNE. This study’s findings highlighted the diurnal variation of excretion for certain EDC, but not for others, in real-life conditions. The degree of EDC chronotoxicity in distinct diurnal windows of the day warrants further investigation with longitudinal human studies.

Free Cortisol Mediates Associations of Maternal Urinary Heavy Metals with Neonatal Anthropometric Measures: A Cross-Sectional Study

Prenatal exposure to heavy metals is known to be associated with adverse birth outcomes and oxidative stress biomarkers. In this study, we examined whether maternal free cortisol or 8-Hydroxy-2-Deoxyguanosine (8-OHdG) could mediate associations between maternal heavy metal exposure and birth outcomes. A total of 182 healthy pregnant women were recruited. Heavy metals (including Pb, Hg, and Cd), free-cortisol, and 8-OHdG were analyzed in urine at delivery. Birth outcomes including birth weight, length, Ponderal index, and head circumference were measured. To examine associations of maternal urinary heavy metals with biomarkers and birth outcomes, generalized linear models were employed. Birth length was positively associated with Pb (β = 0.78, 95% CI: 0.09−1.46) and Hg (β = 0.84, 95% CI: 0.23−1.45) (both p < 0.05). The Ponderal index, a measure of a newborn’s leanness, was negatively associated with maternal urinary Pb (β = −0.23, 95% CI: −0.46−−0.07) and Hg (β = −0.26, 95% CI: −0.44−−0.08) (both p < 0.05). No association between maternal Cd and birth outcomes was observed. Most heavy metals showed positive associations with free cortisol and 8-OHdG. Free cortisol was identified as a mediator underlying the observed relationship between Hg and birth length or Ponderal index. This study observed adverse birth outcomes from maternal exposures to Pb and Hg. Increased free cortisol related to Hg exposure was suggested as a possible causal pathway from Hg exposure to birth outcomes such as the Ponderal index.

Estimation of parabens and bisphenols in maternal products and urinary concentrations in Indian pregnant women: daily intake and health risk assessment

The presence of parabens and bisphenols in maternal products and usage during pregnancy have raised serious concern about their possible harm to pregnant women. The concentrations of six parabens and eight bisphenols were quantified by high-performance liquid chromatography-tandem mass spectrometry in the samples of commercially available herbal-based ayurvedic maternal products and urine of healthy pregnant women from Assam, India. Methyl paraben (MP) and bisphenol AF (BPAF) were found to be more dominant in the maternal products, whereas MP, bisphenol A (BPA), and BPAF were dominant in urine samples of healthy pregnant women. The sum of the mean concentrations of all forms of parabens and bisphenols in maternal products were 48,308.50 ng/g and 542.42 ng/g, respectively, and urine 101.33 ng/mL and 23.42 ng/mL, respectively. The estimated daily intake (EDI) of total parabens and bisphenols in maternal products were 7378.02 and 19.78 ng/kg body weight/day, respectively. EDI of total parabens and bisphenols from urinary concentrations were 690.12 and 111.33 μg/kg body weight/day, respectively. The concentrations of butyl (BP) and heptyl (HP) parabens have a significant positive correlation with birth weight. The hazard quotient (HQ) value of MP, EP, and BPA was less than 1, and margin of exposure (MOE) identified potential risk associated with propyl paraben. Results from Monte-Carlo risk assessment analysis did not exceed the acceptable daily intake (ADI). Our results showed that higher concentrations of parabens and bisphenols are present in maternal products and the urine of healthy pregnant women. Hence maternal products containing bisphenols and parabens should be used cautiously during pregnancy to avoid maternal and fetal complications.

In utero exposure to parabens and early childhood BMI z-scores - Associations between placental ethyl paraben, longitudinal BMI trajectories and cord blood metabolic biomarkers

BACKGROUND

Parabens are used as antimicrobial preservatives in personal care products. Few studies have dealt with adverse health outcomes, transplacental transfer, and obesogenic effects of prenatal exposure to parabens. We examined the association between placental paraben levels and cord blood metabolic biomarkers, considering modulating effects of maternal pre-pregnancy BMI and underlying epigenetic mechanisms, and investigated longitudinal effects of in utero paraben exposure on early childhood trajectories of BMI z-scores.

METHODS

Placental concentrations of four parabens [methyl (MeP), ethyl (EtP), propyl (PrP), and butyl (BuP)] were measured by ultra-performance liquid chromatography/tandem mass spectrometry in 229 placentas of the ENVIRONAGE birth cohort. The association with cord blood metabolic biomarkers [glucose, insulin, γ-glutamyltransferase (GGT), high-density and low-density lipoprotein (HDL and LDL)] was analyzed in multiple regression models with two different sets of, a priori selected potential confounders, additionally stratified for different maternal BMI groups and assessed by causal mediation analysis. The association between placental paraben concentration and differential DNA methylation of CpGs annotated to GGT and longitudinal measurements of BMI z-scores were investigated with adjusted linear mixed models.

RESULTS

The geometric means of placental MeP, EtP, PrP, and BuP levels above the limit of detection (LOD) were 4.42, 1.32, 1.51, and 0.35 ng/g respectively, with only EtP showing sufficient (88%) measurements above LOD for further analyses. An interquartile ratio (IQR) increase in placental EtP was associated with an increase of 12.61 % (95% CI: 1.80 24.57) in the geometric mean of cord GGT activity, and with a decrease of -3.64 % (95% CI: -6.80 to -0.39) in the geometric mean of cord glucose. Placental EtP levels were significantly associated with hypermethylation of cg08612779 annotated to GGT7 after correcting for multiple testing (ß = 0.0017, p = 0.049). An interquartile ratio (IQR) increment in placental EtP was associated with a decrease in longitudinal BMI z-score of 0.27 points (95% CI: -0.46 to -0.088).

CONCLUSION

Prenatal EtP exposure may affect early childhood BMI. The association of placental EtP with cord blood GGT and glucose levels provides a starting point for further research on mechanisms of paraben-related metabolic processes in utero.

Placental transport of parabens studied using an ex-vivo human perfusion model

INTRODUCTION

Parabens are a group of chemicals widely used as preservatives in daily consumer products such as cosmetics, food items, pharmaceuticals and household commodities. They have been broadly detected in human samples indicating a general human exposure, and concerns arose from their potential endocrine disrupting effect. Especially the exposure to parabens during pregnancy is concerning, as the time of fetal development is a particularly vulnerable period. The aim of this study was to investigate the transport and metabolism of four commonly used parabens: methyl-, ethyl-, propyl- and butylparaben (MeP, EtP, PrP and BuP) and the metabolite para-hydroxybenzoic acid (PHBA) across the human placenta.

METHODS

An ex-vivo human placental perfusion model was used. The test compounds were added in the maternal compartment (with initial concentrations of 1 mM or 0.1 mM). Placental transport was evaluated by fetal-maternal concentration ratios (FM-ratio), transport index (TI) and indicative permeability (IP).

RESULTS

Information about parabens kinetics was taken from 10 perfusions and PHBA from 7 perfusions. Paraben metabolism was not detected. The placental transport of MeP, EtP, PrP, BuP and PHBA revealed a transfer from maternal to fetal circulations with FM₁₂₀ of 0.86 ± 0.27 (MeP), 0.98 ± 0.28 (EtP), 1.00 ± 0.28 (PrP), 1.12 ± 0.59 (BuP) and 0.82 ± 0.37 (PHBA). The test substances accumulated in the perfused tissue in some degree. The average kinetic parameters FM-ratio, TI and IP were not different between chemicals.

DISCUSSION

The present study shows that the placenta barrier is permeable to all four parabens and the metabolite, which implies potential fetal exposure.

Xenoestrogen exposure and kidney function in the general population: Results of a community-based study by laboratory tests and questionnaire-based interviewing

BACKGROUND

Chronic kidney disease (CKD) is a growing concern worldwide. Exposure to xenoestrogens (XEs), such as phthalates, parabens, and phenols, lead to CKD. However, kidney function and its complex relationship with XEs, lifestyle, and dietary habits are not well understood.

METHODS

In the present cross-sectional community-based cohort study, we enrolled 887 subjects for a questionnaire-based interview and laboratory tests. XE exposure concerning lifestyle/dietary habits were evaluated using questionnaires. Urinary levels of 17XE metabolites were measured in 60 subjects with high exposure risk scores and 60 subjects with low exposure risk scores.

RESULTS

Univariate and multivariate linear regression showed that a high exposure score (β ± SE: 4.226 ± 1.830, P = 0.021) was independently negatively associated with eGFR in 887 subjects. Univariate and multivariate linear regression to urinary XEs and urine albumin creatinine excretion ratio (UACR) in 120 subjects indicated that ethylparaben (EP) (β: 1.934, 95% CI: 0.135-3.733, P = 0.035) was significantly associated with increased UACR. Multivariate regression analyses of the CKD subgroup (n = 38), after adjusting for age, showed that higher levels of mono-(2-ethylhexyl) phthalate (MEHP), EP, nonylphenol (NP), and benzophenone-3 (BP-3) were significantly associated with lower estimated glomerular filtration rate (eGFR). Higher urinary levels of MEHP (OR: 3.037, 95% CI: 1.274-7.241) were more likely associated with high exposure scores (>5 points), after adjusting for diabetes, gender, eGFR, age, Na, Ca, albumin, vitamin D, systolic blood pressure (SBP), white blood cell count, total bilirubin, aspartate transaminase, and heart rate. MEHP (β ± SE: 0.033 ± 0.009, P < 0.001) was also significantly positively associated with total exposure scores after applying multivariate linear regression analyses.

CONCLUSION

XE exposure scores obtained from the questionnaires were negatively associated with kidney function. Urinary metabolites of XEs, including EP, NP, BP-3, and MEHP, are potential risk factors for microalbuminuria and decline in kidney function. MEHP seemed to have the strongest correlation with high exposure scores and decline in kidney function.

Urinary level of un-metabolized parabens in women working in beauty salons

Parabens are a group of chemical additive extensively utilized in various health care products and ubiquitously observed in the different environmental matrixes. Nevertheless, the exposure of women working in beauty salons to these pollutants is not well-documented. For this purpose, 50.00 women working in beauty salons were chosen as the exposed group (EG) and 35.00 housewives were chosen as the control group (GC). The concentration of methyl paraben (MeP), ethyl paraben (EtP), butyl paraben (BuP), propyl paraben (PrP), benzyl paraben (BzP), heptyl paraben (HepP), and para-hydroxybenzoic acid (4-HB) metabolite were quantified in the collected urine samples. It was seen that paraben sexist with a high detection frequency (DF) in the urine of women working in beauty salons. The results also revealed that the significant difference between the urinary parabens level in the EG and CG (P value < 0.05). The median concentration of Σparaben and HB-4 metabolite in the before exposure (BE) samples was 124.00 and 219.00 μg/L, while in the after exposure (AE) samples, it was 156.00 and 249.00 μg/L, respectively. Moreover, the parabens levels in the AE samples were considerably higher than in BE samples in women working in beauty salons (P value < 0.05). This research also documented that "personal care products (PCPs) usage" can be known as a leading factor for the urinary paraben level in the studied individuals. The median total estimated daily intakes (TEsDI) for MeP, EtP, and PrP for the studied women were obtained as 8.02, 4.57, and 7.88 μg/L respectively. Also, a significant and positive association was observed between EtP, PrP as well as BuP and 8-OhdG (as a DNA oxidative stress biomarker) (P value < 0.01). Further, a significant and positive association was found between EtP as well as BuP and some biomarkers of kidney damage (like uTIMP-1 and uKim-1). Accordingly, it can be stated that women working in beauty salons are at a high risk in terms of DNA oxidative stress and kidney damage.

Prenatal urinary concentrations of phenols and risk of preterm birth: exploring windows of vulnerability

OBJECTIVE

To explore windows of vulnerability to prenatal urinary phenol concentrations and preterm birth.

DESIGN

Prospective cohort.

SETTING

A large fertility center in Boston, Massachusetts.

PATIENT(S)

A total of 386 mothers who sought fertility treatment and gave birth to a singleton between 2005 and 2018.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Singleton live birth with gestational age <37 completed weeks.

RESULT(S)

Compared with women with non-preterm births, urinary bisphenol A (BPA) concentrations were higher across gestation among women with preterm births, particularly during mid-to-late pregnancy and among those with female infants. Second trimester BPA concentrations were associated with preterm birth (Risk Ratio [RR] 1.24; 95%CI: 0.92, 1.69), which was primarily driven by female (RR 1.40; 95%CI: 1.04, 1.89) and not male (RR 0.85; 95%CI 0.50, 1.46) infants. First trimester paraben concentrations were also associated with preterm birth (RR 1.17; 95%CI: 0.94, 1.46) and similarly the association was only observed for female (RR 1.46; 95% CI: 1.10, 1.94) and not male infants (RR 0.94; 95%CIC: 0.72, 1.23). First trimester urinary bisphenol S concentrations showed a suggested risk of preterm birth (RR 1.25; 95%CI: 0.82, 1.89), although the small case numbers precluded sex-specific examination.

CONCLUSION(S)

We found preliminary evidence of associations between mid-to-late pregnancy BPA and early pregnancy paraben concentrations with preterm birth among those with female infants only. Preterm birth risk may be compound, sex, and window specific. Given the limited sample size of this cohort, results should be confirmed in larger studies, including fertile populations.

Parabens as chemicals of emerging concern in the environment and humans: A review

Parabens are one of the most widely used preservatives in food, pharmaceuticals and personal care products (PCPs) because of their advantageous properties and low toxicity based on the early assessments. However, recent research indicates that parabens may act as endocrine-disrupting chemicals (EDCs) and thus, are considered as chemicals of emerging concern that have adverse human health effects. To provide the basis for future human health studies, we reviewed relevant literature, published between 2005 and 2020, regarding the levels of parabens in the consumer products (pharmaceuticals, PCPs and food), environmental matrices and humans, including susceptible populations, such as pregnant women and children. The analysis showed that paraben detection rates in consumer products, environmental compartments and human populations are high, while the levels vary greatly by country and paraben type. The concentrations of parabens reported in pregnant women (~20-120 μg/L) were an order of magnitude higher than in the general population. Paraben concentrations in food and pharmaceuticals were at the ng/g level, while the levels in PCPs reached mg/g levels. Environmental concentrations ranged from ng/L-μg/L in surface waters to tens of μg/g in wastewater and indoor dust. The levels of human exposure to parabens appear to be higher in the U.S. and EU countries than in China and India, which may change with the increasing production of parabens in the latter countries. The review provides context for future studies to connect paraben exposure levels with human health effects.

The sex-specific association between maternal urinary paraben levels and offspring size at birth

Parabens are a group of antimicrobial preservatives applied in an extensive range of products and are suspected to impair fetal growth because of their disrupting effect on the endocrine system. We aimed to examine maternal urinary paraben concentrations and their neonates' outcome indexes. Methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) concentrations were measured in 105 maternal urine samples collected before delivery. Length, weight, and head circumference at birth were extracted from the mothers' delivery files. A multivariable linear regression analysis was performed to evaluate the association between paraben levels and neonatal anthropometric indices. The median levels of urinary parabens, especially BP, were higher than those in other countries. Prenatal urinary concentration of MP and BP showed a significantly positive association with birth weight in all neonates (β = 0.79, 95% CI: 0.16, 1.41, and β = 8.56, 95% CI: 3.95, 13.17, respectively), while these chemicals showed a significant negative association with head circumference (β = - 0.002, 95% CI: - 0.004, - 0.000, and β = - 0.016, 95% CI: - 0.030, - 0.002, respectively). A significant positive association between MP and birth length was also found (β = 0.004, 95% CI: 0.00, 0.00) in all the neonates. In sex-stratified adjusted models, MP and BP were found to be associated, respectively, with higher birth length and weight in male neonates (β = 0.008, 95% CI: - 0.001, 0.017, and β = 7.948, 95% CI: 1.045, 14.851). In girls, maternal urinary MP, PP, and BP were associated with increased birth weight (β = 0.831, 95% CI: 0.043, 1.620; β = 4.178, 95% CI: 0.877, 7.480; and β = 10.821, 95% CI: 3.545, 18.097, respectively), and MP and BP were associated with reduced head circumference at birth (β = - 0.003, 95% CI: - 0.005, - 0.001, and β = - 0.035, 95% CI: - 0.055, - 0.016). These results revealed potential impacts between neonatal growth and maternal exposure to parabens. However, these findings should be interpreted while considering the limitations of the present study.

Exposure to parabens and associations with oxidative stress in adults from South China

Parabens are widely applied as preservatives in cosmetics, drugs and food. Previous studies suggested that parabens could exhibit potential risks to human health. However, data on human exposure levels and health effects of parabens remain limited, especially in the potential effects on DNA oxidative stress. This study aimed to investigate urinary levels of parabens in adults from South China and explore the relationships between urinary parabens and DNA oxidative stress. Five short chain parabens, including methyl paraben (MeP), ethyl paraben (EtP), n-propyl paraben (PrP), butyl paraben (BuP) and benzyl paraben (BzP), were determined in urine from 319 adults in Shenzhen, China. MeP, EtP and PrP were frequently detected in urine samples (detection frequencies >66.5%), suggesting broad exposure in South China adults. Median concentrations of MeP, EtP, PrP, BuP and BzP were 5.78, 0.39, 0.35, 0.01 and 0.02 μg/L, respectively. A significantly positive correlation was observed between the urinary concentrations of MeP and PrP (p < 0.01), suggesting similar sources for these two chemicals. In addition, participants with alcohol consumption exhibited significantly lower paraben concentrations in urine than those without alcohol drinking (p < 0.05). Significant association was observed between urinary concentrations of parabens and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels (p < 0.01), while no significant dose-response relationship was found (p > 0.05). A potential risk from PrP exposure was found in South China adults.

Praegnatio Perturbatio-Impact of Endocrine-Disrupting Chemicals

The burden of adverse pregnancy outcomes such as preterm birth and low birth weight is considerable across the world. Several risk factors for adverse pregnancy outcomes have been identified. One risk factor for adverse pregnancy outcomes receiving considerable attention in recent years is gestational exposure to endocrine-disrupting chemicals (EDCs). Humans are exposed to a multitude of environmental chemicals with known endocrine-disrupting properties, and evidence suggests exposure to these EDCs have the potential to disrupt the maternal-fetal environment culminating in adverse pregnancy and birth outcomes. This review addresses the impact of maternal and fetal exposure to environmental EDCs of natural and man-made chemicals in disrupting the maternal-fetal milieu in human leading to adverse pregnancy and birth outcomes-a risk factor for adult-onset noncommunicable diseases, the role lifestyle and environmental factors play in mitigating or amplifying the effects of EDCs, the underlying mechanisms and mediators involved, and the research directions on which to focus future investigations to help alleviate the adverse effects of EDC exposure.

Impact of gestational exposure to endocrine disrupting chemicals on pregnancy and birth outcomes

With the advent of industrialization, humans are exposed to a wide range of environmental chemicals, many with endocrine disrupting potential. As successful maintenance of pregnancy and fetal development are under tight hormonal control, the gestational exposure to environmental endocrine disrupting chemicals (EDC) have the potential to adversely affect the maternal milieu and support to the fetus, fetal developmental trajectory and birth outcomes. This chapter summarizes the impact of exposure to EDCs both individually and as mixtures during pregnancy, the immediate and long-term consequences of such exposures on the mother and fetus, the direct and indirect mechanisms through which they elicit their effects, factors that modify their action, and the research directions to focus future investigations.

High urinary concentrations of parabens and bisphenol A in very low birth weight infants

Very low birth weight infants (VLBW; birth weight < 1500 g) are treated with pharmaceuticals and medical equipment containing parabens and bisphenol A (BPA). Parabens are used in pharmaceuticals, whereas BPA in medical equipment where concentrations are rarely reported in hospitalised VLBW infants. We measured urinary concentrations of parabens and BPA and hypothesised high and increasing concentrations in infants born at lower gestational ages (GAs), and among infants with bronchopulmonary dysplasia (BPD) and late-onset septicaemia (LOS) due to higher exposure from pharmaceuticals and medical equipment. Urinary samples were collected during the first (n = 38) and fifth (n = 36) week of life. Methylparaben, ethylparaben, propylparaben, butylparaben, and BPA concentrations were measured using ultra high-performance liquid chromatography coupled to tandem mass spectrometry. VLBW infants had very high urinary concentrations of parabens and BPA compared to term infants and older children. The Σ paraben concentration was higher than detected in previous studies on premature infants. Lower GA at birth was associated with higher concentrations of parabens and BPA. Infants born before 28 weeks GA had higher first week concentrations of propylparaben (38.6 vs. 9.05 ng/mL, p = 0.007), butylparaben (0.28 vs. 0.09 ng/mL, p = 0.05) and fifth week concentrations of BPA (15.1 vs. 6.02 ng/mL, p = 0.02) than infants born after 28 weeks GA. Infants with LOS and BPD had higher fifth week concentrations of BPA than infants without LOS and BPD (LOS: 14.2 vs. 6.77 ng/mL, p = 0.07; BPD: 18.6 vs. 7.62 ng/mL, p = 0.05).

Cosmetic and personal care product use, urinary levels of parabens and benzophenones, and risk of endometriosis: results from the EndEA study

AIM

To explore the relationship of urinary concentrations of different congeners of benzophenones and parabens with the utilization of cosmetics and personal care products (PCPs) and their impact on the risk of endometriosis, and to evaluate the influence of oxidative stress on associations found.

METHODS

This case-control study comprised a subsample of 124 women (35 cases; 89 controls). Endometriosis was confirmed (cases) or ruled out (controls) by laparoscopy, with visual inspection of the pelvis and biopsy of suspected lesions (histological diagnosis). Urinary concentrations of benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-hydroxibenzophenone (4-OH-BP), methyl- (MeP), ethyl- (EtP), propyl- (PrP), and butyl-paraben (BuP), and biomarkers of oxidative stress [lipid peroxidation (TBARS) and total antioxidant power (TAP)] were quantified. Information was gathered on the frequency of use of cosmetics and PCPs. Associations between the frequency of cosmetics/PCP use, urinary concentrations of benzophenones and parabens, oxidative stress, and endometriosis risk were explored in logistic and linear multivariable regression analyses.

RESULTS

The frequency of utilization of certain cosmetics and PCPs was significantly associated with urinary concentrations of benzophenones and parabens. After adjustment for potential confounders, the risk of endometriosis was increased in women in the second versus first terciles of MeP (OR = 5.63; p-value<0.001), BP-1 (OR = 5.12; p-value = 0.011), BP-3 (OR = 4.98; p-value = 0.008), and ƩBPs (OR = 3.34; p-value = 0.032). A close-to-significant relationship was observed between TBARS concentrations and increased endometriosis risk (OR = 1.60, p-value = 0.070) and an inverse association between TAP concentrations and this risk (OR = 0.15; p-value = 0.048). Oxidative stress results did not modify associations observed between benzophenone/paraben exposure and endometriosis risk.

CONCLUSIONS

Our findings indicate that the frequency of cosmetics and PCP utilization is a strong predictor of exposure to certain benzophenone and paraben congeners. These compounds may increase the risk of endometriosis in an oxidative stress-independent manner. Further studies are warranted to corroborate these findings.

Behavioural effects of early-life exposure to parabens in zebrafish larvae

Parabens are classified as endocrine disrupting chemicals due to their ability to activate several nuclear receptors causing changes in hormones-dependent signalling pathways. Central nervous system of developing organisms is particularly vulnerable to changes in hormonal pathways, which could lead to altered brain function, abnormal behaviour and even diseases later in life. The aim of the present study was to investigate the effects of exposure to butylparaben (BuP), ethylparaben (EtP) and methylparaben (MeP) during early development on nervous system using zebrafish larvae's behavioural models. Zebrafish were exposed until 4 days post fertilization (dpf) to three concentrations of each paraben chosen considering the environmentally realistic concentrations of human exposure and the benchmark-dose lower bound calculated for zebrafish larvae (BuP: 5, 50 and 500 μg/L; EtP: 50, 500 and 5000 μg/L; MeP: 100, 1000 and 10,000 μg/L). Activity in novel and in familiar environment, thigmotaxis, visual startle response and photic synchronization of the behavioural circadian rhythms were analysed at 4, 5 and 6 dpf. Zebrafish larvae exposed to BuP 500 μg/L and EtP 5000 μg/L revealed increased anxiety-like behaviour in novel environment. Larvae treated with 500 μg/L of BuP showed reduced activity in familiar and marginally in unfamiliar environment, and larvae exposed to 5000 μg/L of EtP exhibited hyperactivity in familiar environment. Parabens exposure did not influence the visual startle response and the photic synchronization of circadian rhythms in zebrafish larvae. This research highlighted as the exposure to parabens has the potential to interfere with behavioural development of zebrafish.

Determination of prenatal exposure to parabens and triclosan and estimation of maternal and fetal burden

BACKGROUND

Parabens (PBs) and triclosan (TCS) are generally used as antimicrobials mostly in personal care products. Their wide prevalence in daily products raised an acute need for the biomonitoring of these contaminants and the investigation of possible health impacts.

MATERIAL AND METHODS

In this study we aimed to quantitatively determine PBs and TCS levels in urine and amniotic fluid samples using a liquid chromatography - mass spectrometry system (LC-MS). Ninety nine (99) pregnant women took part in this research. The samples were collected during the amniocentesis in the early second trimester of their pregnancy. Women of all ages, education, household income and profession were selected. The exposure and the burden of pregnant women and their infants were also evaluated.

RESULTS

The most prevalent compound in urine, among the analyzed, was TCS with 74.7 % positive samples while in amniotic fluid methyl paraben (MePB) with 21.2 % positive samples. MePB was detected at higher concentrations in urine (mean: 378.5 ng/mL) followed by TCS (mean: 55.3 ng/mL), ethyl paraben (EtPB) (mean: 23.2 ng/mL) and butyl paraben (BuPB) (mean: 2.3 ng/mL) while benzyl paraben (BePB) was not detected in any urine sample. Concentrations in amniotic fluid samples were much lower. In particular, the mean concentrations were 6.6 ng/mL for MePB, 9.2 ng/mL for EtPB, 0.4 ng/mL for BuPB, 0.6 ng/mL for BePB and 1.8 ng/mL for TCS. The detected levels of all analytes in urine were correlated with those in amniotic fluid but no statistically significant results arose (p >n0.05). Negative associations were observed between amniotic fluid levels of MePB and maternal age (p = 0.05) while both urinary and amniotic levels of TCS were correlated with maternal BMI (p = 0.04). Somatometric characteristics of the infants showed no statistical significant associations with the detected levels of PBs and TCS.

CONCLUSION

This study indicated a strong/possible association between exposure of pregnant women to TCS and higher/lower maternal body weight gain during pregnancy. The same trend was observed between amniotic fluid MePB levels and maternal age. However, no statistically significant associations were observed between neonatal somatometric characteristics or health status and PBs and TCS levels.

Cross-Sectional Estimation of Endogenous Biomarker Associations with Prenatal Phenols, Phthalates, Metals, and Polycyclic Aromatic Hydrocarbons in Single-Pollutant and Mixtures Analysis Approaches

BACKGROUND

Humans are exposed to mixtures of toxicants that can impact several biological pathways. We investigated the associations between multiple classes of toxicants and an extensive panel of biomarkers indicative of lipid metabolism, inflammation, oxidative stress, and angiogenesis.

METHODS

We conducted a cross-sectional study of 173 participants (median 26 wk gestation) from the LIFECODES birth cohort. We measured exposure analytes of multiple toxicant classes [metals, phthalates, phenols, and polycyclic aromatic hydrocarbons (PAHs)] in urine samples. We also measured endogenous biomarkers (eicosanoids, cytokines, angiogenic markers, and oxidative stress markers) in either plasma or urine. We estimated pair-wise associations between exposure analytes and endogenous biomarkers using multiple linear regression after adjusting for covariates. We used adaptive elastic net regression, hierarchical Bayesian kernel machine regression, and sparse-group LASSO regression to evaluate toxicant mixtures associated with individual endogenous biomarkers.

RESULTS

After false-discovery adjustment (q<0.2), single-pollutant models yielded 19 endogenous biomarker signals associated with phthalates, 13 with phenols, 17 with PAHs, and 18 with trace metals. Notably, adaptive elastic net revealed that phthalate metabolites were selected for several positive signals with the cyclooxygenase (n=7), cytochrome p450 (n=7), and lipoxygenase (n=8) pathways. Conversely, the toxicant classes that exhibited the greatest number of negative signals overall in adaptive elastic net were phenols (n=20) and metals (n=21).

DISCUSSION

This study characterizes cross-sectional endogenous biomarker signatures associated with individual and mixtures of prenatal toxicant exposures. These results can help inform the prioritization of specific pairs or clusters of endogenous biomarkers and exposure analytes for investigating health outcomes. https://doi.org/10.1289/EHP7396.

The controversies of parabens - an overview nowadays

Effects of paraben toxicity, i.e., endocrine-disruption properties, are in the focus of researchers for decades, but still - they are a hot subject of debate. Parabens are aliphatic esters of p-hydroxybenzoic acid, which are widely used as antimicrobial agents for the preservation of cosmetics, pharmaceuticals and foods. Mostly used parabens are methyl-, ethyl-, propyl- and butylparaben. Although the toxicity of parabens is reported in animals and in in vitro studies, it cannot be taken for granted when discussing hazards for human health due to an unrealistic exposure -safety profile. Many studies have demonstrated that parabens are non-teratogenic, non-mutagenic, non-carcinogenic and the real evidence for their toxicity in humans has not been established. For now, methyl-, ethyl- and propylparaben are considered safe for use in cosmetics and pharmaceuticals within the recommended range of doses. Regarding alternatives for parabens, a variety of approaches have been proposed, but every substitute would need to be tested rigorously for toxicity and safety.

Serum levels of non-persistent environmental pollutants and risk of incident hypertension in a sub-cohort from the EPIC study

BACKGROUND

The prevalence of arterial hypertension (AHT), a well-known risk factor for cardiovascular disease, has considerably increased over last decades. Non-persistent environmental pollutants (npEPs) are a group of ubiquitous chemicals, widely used in consumer products such as food packaging and cosmetics, which have been identified as endocrine disrupting chemicals and obesogens. The aim of this study was to assess the potential associations of serum levels of three groups of npEPs with the risk of incident AHT.

METHODS

Cohort study within a sub-cohort of Granada EPIC-Spain center (n = 670). We quantified serum concentrations of three groups of npEPs, i.e., bisphenol A (BPA), four parabens: methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP), and two benzophenones: benzophenone 1 (BP1), benzophenone 3 (BP3), in samples collected at recruitment. Statistical analyses were performed by means of Cox Proportional Hazard Models.

RESULTS

Median follow-up time was 23 years. BPA and MP were found in >80% of the study population. Individuals within the 4th PP quartile (0.53-9.24 ng/ml) showed a statistically significant increased risk of AHT (HR = 1.40, p = 0.015). No associations were found for the rest of pollutants.

CONCLUSIONS

Overall, we evidenced no associations of most npEPs with AHT risk, with the exception of an increased risk in the highest PP percentiles. Considering the limitations of using one spot serum sample for exposure characterization, further research on the potential contribution of npEPs on the development of AHT risk is warranted.

Association of maternal urinary concentration of parabens and neonatal anthropometric indices

PURPOSE

Parabens are used as preservatives in a wide range of products. Although parabens are generally known as safe, but recent evidences indicate that these compounds could lead to potential adverse effects on fetal growth. Thus, this study aimed to investigate the association between maternal parabens level in a sample of Iranian pregnant women with neonatal anthropometric measures.

METHODS

This cross-sectional study was conducted in 2018-2019 in Isfahan city, Iran. Early morning urine samples were collected from 117 pregnant women who were in their first trimester of pregnancy. The urinary concentrations of four parabens including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were measured by gas chromatography-mass spectrometry. To compensate for variation in urine dilution, the paraben concentrations were adjusted by the creatinine levels. Associations between maternal parabens level and neonatal anthropometric indices were evaluated.

RESULTS

The MeP, EtP, PrP, and BuP were detected in %92, %36, %65, and %89 of the urine samples, respectively. No significant association was observed between maternal parabens level and birth length (p-value>0.05). In adjusted model, the BuP concentration in first trimester urine samples showed significantly negative association with head circumference in female neonates [β = -0.013, 95% CI: -0.024, -0.003], while positive significant association with that index in male neonates [β = 0.019, 95% CI: 0.001, 0.038]. In subgroup analysis by sex, in crude and adjusted analyses BuP was found to be only associated with higher birth weight in female neonates. PrP also showed significant positive association with head circumference and birth weight of male neonates in crude analysis.

CONCLUSION

Findings of this study on the association of urinary parabens of pregnant mothers with birth weight and head circumference suggest that maternal exposure to parabens might impact the fetal growth, However, these findings are based on cross-sectional data, thus the results should be interpreted with caution. The current findings underscore the necessity of providing more strict regulations in industries for limiting parabens use in their products, and the importance of public education for women of reproductive age for using paraben-free compounds.

Role of environmental pollutants in Alzheimer's disease: a review

Neurodegenerative disorders are commonly erratic influenced by various factors including lifestyle, environmental, and genetic factors. In recent observations, it has been hypothesized that exposure to various environmental factors enhances the risk of Alzheimer's disease (AD). The exact etiology of Alzheimer's disease is still unclear; however, the contribution of environmental factors in the pathology of AD is widely acknowledged. Based on the available literature, the review aims to culminate in the prospective correlation between the various environmental factors and AD. The prolonged exposure to the various well-known environmental factors including heavy metals, air pollutants (particulate matter), pesticides, nanoparticles containing metals, industrial chemicals results in accelerating the progression of AD. Common mechanisms have been documented in the field of environmental contaminants for enhancing amyloid-β (Aβ) peptide along with tau phosphorylation, resulting in the initiation of senile plaques and neurofibrillary tangles, which results in the death of neurons. This review offers a compilation of available data to support the long-suspected correlation between environmental risk factors and AD pathology. Graphical abstract .

Parabens in stretch mark creams: A source of exposure in pregnant and lactating women

Parabens are widely used as antimicrobial preservatives in personal care products (PCPs). Stretch mark cream is widely used by pregnant and lactating women for the treatment of striae gravidarum. This can be a potential source of paraben exposure, not only to pregnant/lactating women but also to fetuses/newborns. Little is known, however, with regard to the occurrence of parabens in stretch mark creams. In this study, we analyzed eight parabens and their metabolites in 31 popular stretch mark creams originated from various countries including China. The concentrations of Σparaben (sum of eight parabens/metabolites) ranged from 0.007 to 1630 μg/g, with mean and median values of 453 and 273 μg/g, respectively. Methyl- and propyl-parabens accounted for >95% of Σparaben concentrations. We examined the measured paraben concentrations against ingredients listed on the product labels. Parabens were listed as ingredients in those creams that contained concentrations >100 μg/g except for four samples with such high concentrations. Six cream samples that were labeled 'paraben-free' contained trace levels (0.007-9.92 μg/g) of these preservatives. Mean dermal ∑paraben exposure dose from the use of stretch mark creams (30.6 μg/kg bw/day) was well below the current acceptable daily intake value (5 mg/kg bw/day). In comparison to diet and indoor dust ingestion pathways, paraben-laden stretch mark cream may be a major source of paraben exposure in pregnant and lactating women. This study provides information on parabens and other preservatives in stretch mark creams and measures to reduce exposures during pregnancy and lactation.

Concentration and Variability of Urinary Phthalate Metabolites, Bisphenol A, Triclosan, and Parabens in Korean Mother–Infant Pairs

Concentrations of toxic chemicals in mothers highly correlate with those in their children; moreover, the levels are higher in children than in mothers. Non-persistent chemicals with a short half-life including phthalate metabolites, bisphenol A (BPA), triclosan (TCS), and parabens are metabolized and excreted through urine. Therefore, we assessed the urine concentrations of phthalate metabolites, BPA, TCS, and parabens; correlated the concentrations with exposure levels; and assessed the within-individual variability of these chemicals in mothers and their infants. We collected 225 and 71 samples from 45 mothers and 36 infants, respectively. For the variability analysis, 189 and 42 samples were collected from nine mothers and their infants, respectively. The median concentrations of phthalate metabolites in the mothers and infants were 0.53–26.2 and 0.81–61.8 μg/L, respectively, and those of BPA, TCS, and parabens were 0.24–76.3 and 2.06–12.5 μg/L, respectively. The concentrations of monoethyl phthalate (MEP), mono-N-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), and BPA in the mothers were positively correlated with those in infants (0.45, 0.62, and 0.89, respectively; p < 0.05), whereas toxic chemical concentrations in infants were higher than those in the mothers. With respect to the within-individual intraclass correlation coefficient (ICC), the first morning void (FMV) of the mothers had high ICCs for all chemicals (range: 0.72–0.99), except for BPA, monobenzyl phthalate (MBzP), and monocarboxyoctyl phthalate (MCOP). The ICC values of most chemicals were moderate to high (range: 0.34–0.99) in the first morning void. However, there were different patterns of ICCs in the infants. These findings indicate the importance of mother–infant pair studies and the necessity of research in infants, as they have different exposure sources and pathways from adults.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

Urinary Concentrations of Parabens in a Population of Iranian Adolescent and Their Association with Sociodemographic Indicators

Parabens are widely used as preservatives in personal care products, foodstuffs, and pharmaceuticals. Concerns have been raised regarding the potential endocrine disruption effects of parabens. In the present study, the urinary concentration of four common parabens, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), in 100 Iranian adolescents randomly referring to health services centres were analyzed using GC/MS. The association of sociodemographic and lifestyle variables, collected through questionnaire, with the concentration of parabens also were studied. Median concentrations of MP, EP, PP, and BP were 92.21, 8.46, 12.26, and 8.42 µg/g creatinine, respectively. There was a strong positive significant correlation between MP and PP (r = 0.694) and moderate to a weak correlation between the other parabens. The concentration of urinary MP in females was significantly higher than those in male (p = 0.021). There was a significant negative association between different BMI groups and MP and EP. There also was a positive significant association between the MP and age, and between MP, EP, and PP, and tobacco use. Although the estimated daily intake of the parabens was lower than the Acceptable Daily Intake, it was higher than those reported in other countries. This confirms the widespread exposure of Iranian adolescents to the paraben compounds and their association with sociodemographic factors. This was the first study reporting the urinary parabens level in Iranian adolescents, and the data can be used as a basis for assessing the risk of exposure to parabens in the Iranian population in future studies.

A Novel HPLC Method for Simultaneous Determination of Methyl, Ethyl, n-propyl, Isopropyl, n-butyl, Isobutyl and Benzyl Paraben in Pharmaceuticals and Cosmetics

INTRODUCTION

The alkyl esters of p-hydroxybenzoic acid at the C-4 position, "the parabens," including methyl, ethyl, propyl, and butyl, are widely used as antimicrobial preservatives in foods, cosmetics, and pharmaceuticals. Official regulations on the use of these compounds make their analysis essential for the estimation of their exposure.

METHODS

On this basis, the presented study was realized to develop a simple, selective and cheap high-performance liquid chromatographic method for the quantitative determination of methylparaben, ethylparaben (EP), n-propyl paraben (NPP), isopropyl paraben (IPP), n-butyl paraben (NBP), isobutyl paraben (IBP) and benzyl paraben (BP) in pharmaceuticals and cosmetic products.

RESULTS

The chromatographic separation of the analytes was achieved under flow rate gradient elution conditions using a C18-bonded core-shell silica particle column (2.6 μm particle size, 150 × 3.0 mm from Phenomenex Co.). The samples were injected into the system as aliquots of 1.0 μL, and the compounds were detected by using a photodiode array detector set at 254 nm wavelength. With this technique, seven paraben derivatives can be determined in the concentration range of 250-2000 ng/mL. The recovery of the method is in the range of 99.95-13.84%, and the RSD is at a maximum value of 3.95%.

CONCLUSION

The proposed method was fully validated and successfully applied to different pharmaceutical and cosmetic samples (n=16), including syrups, suspensions, oral sprays, gels, etc. At least one paraben derivative was detected in six samples and was determined quantitatively. The maximum amount of a paraben derivative found in the analyzed samples was 321.7 ng/mL, which was MP. To the best of our knowledge, this is the first LC method, which is applicable both on pharmaceutical and cosmetic samples.

Cohort profile: Center for Research on Early Childhood Exposure and Development in Puerto Rico

PURPOSE

Puerto Rican children experience high rates of asthma and obesity. Further, infants born in Puerto Rico are more at risk for being born prematurely compared with infants on the mainland USA. Environmental exposures from multiple sources during critical periods of child development, potentially modified by psychosocial factors, may contribute to these adverse health outcomes. To date, most studies investigating the health effects of environmental factors on infant and child health have focused on single or individual exposures.

PARTICIPANTS

Infants currently in gestation whose mother is enrolled in Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort, and infants and children already born to mothers who participated in the PROTECT study.

FINDINGS TO DATE

Data collection and processing remains ongoing. Demographic data have been collected on 437 mother-child pairs. Birth outcomes are available for 420 infants, neurodevelopmental outcomes have been collected on 319 children. Concentrations of parabens and phenols in maternal spot urine samples have been measured from 386 mothers. Center for Research on Early Childhood Exposure and Development mothers have significantly higher urinary concentrations of dichlorophenols, triclosan and triclocarban, but lower levels of several parabens compared with reference values from a similar population drawn from the National Health and Nutrition Examination Survey.

FUTURE PLANS

Data will continue to be collected through recruitment of new births with a target of 600 children. Seven scheduled follow-up visits with existing and new participants are planned. Further, our research team continues to work with healthcare providers, paediatricians and early intervention providers to support parent's ability to access early intervention services for participants.