Parabens: potential impact of low-affinity estrogen receptor binding chemicals on human health

Parabens as the double-edged sword: Understanding the benefits and potential health risks

Parabens are globally employed as important preservatives in pharmaceutical, food, and personal care products. Nonetheless, improper disposal of commercial products comprising parabens can potentially contaminate various environmental components, including the soil and water. Residues of parabens have been detected in surface water, ground water, packaged food materials, and other consumer items. Long-term exposure to parabens through numerous consumer products and contaminated water can harm human health. Paraben can modulate the hormonal and immune orchestra of the body. Recent findings have correlated paraben use with hypersensitivity, obesity, and infertility. Notably, parabens have also been detected in the samples of breast cancer patients, suggesting a potential cross-talk between parabens and carcinogenesis. Therefore, the present article aims to dissect the significance of parabens as a preservative in several consumer products and their impact of chronic exposure to human health. This review encompasses various facets of paraben, including its sources, mechanism of action at the molecular level, and sheds light on its toxicological implications on human health.

Effects of preservatives on the activities of salivary enzymes

OBJECTIVES

To investigate the effects of common preservatives used in oral health care products on the enzymatic activities of lysozyme, peroxidase, and α-amylase in-solution and on-hydroxyapatite surface phases.

DESIGN

The preservatives used in this study were sodium benzoate, methylparaben, propylparaben, and benzalkonium chloride. Hen egg-white lysozyme, bovine lactoperoxidase, and α-amylase from Bacillus sp. served as sources of purified enzymes. Human unstimulated whole saliva was used as a source of salivary enzymes. Hydroxyapatite beads were used as the surface phase. The preservatives were incubated with purified enzymes or saliva samples in-solution or on-hydroxyapatite surface phases, respectively. Enzymatic activities of lysozyme, peroxidase, and α-amylase were measured by hydrolysis of fluorescein-labelled Micrococcus lysodeikticus, oxidation of fluorogenic 2',7'-dichlorofluorescin, and hydrolysis of fluorogenic starch, respectively.

RESULTS

The effects of the preservatives on the enzymatic activities of lysozyme and peroxidase were more distinct in the saliva samples than purified substances, and in the in-solution phase than on-hydroxyapatite surface phase, and the opposite was true for α-amylase. The most significant result was apparent decrease in peroxidase activities caused by the parabens in the in-solution phase (P<0.05). Sodium benzoate and parabens inhibited lysozyme activity in the in-solution phase, but differently for the purified and salivary lysozymes. Parabens and benzalkonium chloride inhibited the enzymatic activity of α-amylase from Bacillus sp., not saliva samples, only on-hydroxyapatite surface (P<0.05).

CONCLUSIONS

Each preservative affected the enzymatic activities of lysozyme, peroxidase, and α-amylase differently. Based on the effects on salivary enzymes, sodium benzoate or benzalkonium chloride was recommended as preservatives rather than parabens.

Unraveling Protein-Metabolite Interactions in Precision Nutrition: A Case Study of Blueberry-Derived Metabolites Using Advanced Computational Methods

Metabolomics, the study of small-molecule metabolites within biological systems, has become a potent instrument for understanding cellular processes. Despite its profound insights into health, disease, and drug development, identifying the protein partners for metabolites, especially dietary phytochemicals, remains challenging. In the present study, we introduced an innovative in silico, structure-based target prediction approach to efficiently predict protein targets for metabolites. We analyzed 27 blood serum metabolites from nutrition intervention studies' blueberry-rich diets, known for their health benefits, yet with elusive mechanisms of action. Our findings reveal that blueberry-derived metabolites predominantly interact with Carbonic Anhydrase (CA) family proteins, which are crucial in acid-base regulation, respiration, fluid balance, bone metabolism, neurotransmission, and specific aspects of cellular metabolism. Molecular docking showed that these metabolites bind to a common pocket on CA proteins, with binding energies ranging from -5.0 kcal/mol to -9.0 kcal/mol. Further molecular dynamics (MD) simulations confirmed the stable binding of metabolites near the Zn binding site, consistent with known compound interactions. These results highlight the potential health benefits of blueberry metabolites through interaction with CA proteins.

Repeated-dose toxicity and toxicokinetic study of isobutylparaben in rats subcutaneously treated for 13 weeks

Parabens have historically served as antimicrobial preservatives in a range of consumables such as food, beverages, medications, and personal care products due to their broad-spectrum antibacterial and antifungal properties. Traditionally, these compounds were believed to exhibit low toxicity, causing minimal irritation, and possessing limited sensitization potential. However, recent evidence suggests that parabens might function as endocrine-disrupting chemicals (EDCs). Consequently, extensive research is underway to elucidate potential human health implications arising from exposure to these substances. Among these parabens, particular concerns have been raised regarding the potential adverse effects of iso-butylparaben (IBP). Studies have specifically highlighted its potential for inducing hormonal disruption, significant ocular damage, and allergic skin reactions. This study aimed to evaluate the prolonged systemic toxicity, semen quality, and estrus cycle in relation to endocrine disruption endpoints, alongside assessing the toxicokinetic behavior of IBP in Sprague-Dawley rats following a 13-week repeated subcutaneous administration. The rats were administered either the vehicle (4% Tween 80) or IBP at dosage levels of 2, 10, and 50 mg/kg/day for 13 weeks. Blood collection for toxicokinetic study was conducted on three specified days: day 1 (1st), day 30 (2nd), and day 91 (3rd). Systemic toxicity assessment and potential endocrine effects were based on various parameters including mortality rates, clinical signs, body weights, food and water consumption, ophthalmological findings, urinalysis, hematological and clinical biochemistry tests, organ weights, necropsy and histopathological findings, estrus cycle regularity, semen quality, and toxicokinetic behavior. The findings revealed that IBP induced local irritation at the injection site in males at doses ≥ 10 mg/kg/day and in females at 50 mg/kg/day; however, systemic toxicity was not observed. Consequently, the no-observed-adverse-effect level (NOAEL) for IBP was determined to be 50 mg/kg/day in rats of both sexes, indicating no impact on the endocrine system. The toxicokinetics of IBP exhibited dose-dependent systemic exposure, reaching a maximum dose of 50 mg/kg/day, and repeated administration over 13 weeks showed no signs of accumulation.

Estrogenic disruption effects and formation mechanisms of transformation products during photolysis of preservative parabens

The ubiquitous presence of emerging contaminants (ECs) in the environment and their associated adverse effects has raised concerns about their potential risks. The increased toxicity observed during the environmental transformation of ECs is often linked to the formation of their transformation products (TPs). However, comprehension of their formation mechanisms and contribution to the increased toxicity remains an unresolved challenge. To address this gap, by combining quantum chemical and molecular simulations with photochemical experiments in water, this study investigated the formation of TPs and their molecular interactions related to estrogenic effect using the photochemical degradation of benzylparaben (BZP) preservative as a representative example. A non-targeted analysis was carried out and three previously unknown TPs were identified during the transformation of BZP. Noteworthy, two of these novel TPs, namely oligomers BZP-o-phenol and BZP-m-phenol, exhibited higher estrogenic activities compared to the parent BZP. Their IC50 values of 0.26 and 0.50 μM, respectively, were found to be lower than that of the parent BZP (6.42 μM). The binding free energies (ΔGbind) of BZP-o-phenol and BZP-m-phenol (-29.71 to -23.28 kcal·mol-1) were lower than that of the parent BZP (-20.86 kcal·mol-1), confirming their stronger binding affinities toward the estrogen receptor (ER) α-ligand binding domain. Subsequent analysis unveiled that these hydrophobic residues contributed most favorably to ER binding, with van der Waals interactions playing a significant role. In-depth examination of the formation mechanisms indicated that these toxic TPs primarily originated from the successive cleavage of ester bonds (OCH2C6H5 and COO group), followed by their combination with BZP*. This study provides valuable insight into the mechanisms underlying the formation of toxic TPs and their binding interactions causing the endocrine-disrupting effects. It offers a crucial framework for elucidating the toxicological patterns of ECs with similar structures.

Asking the Right Questions: Untargeted Metabolomics for Studying Early Pregnancy Paraben Exposures

Periconceptional exposures to three parabens were, surprisingly, associated with dietary sources of these preservatives rather than personal care products, highlighting the utility of this method and need for more study of dietary parabens.

Association between urinary methylparaben level and bone mineral density in children and adolescents aged 8-19 years

Previous epidemiological study has explored a positive association between methylparaben (Mep) and bone mineral density (BMD) in adults. Evidence linking Mep and BMD in children and adolescents is very limited. This study examined the association between Mep and BMD in children and adolescents aged 8-19 years. In this cross-sectional study, 1830 children and adolescents aged 8-19 years from NHANES 2011-2016 were analyzed. Mep was ln-transformed for analysis of the skewed distribution. Multiple linear regression analyses were performed to evaluate Mep's association with BMD (containing total BMD, trunk bone BMD, pelvis BMD, lumbar spine BMD, and thoracic spine BMD). Moreover, a generalized additive model (GAM) and a fitted smoothing curve (penalized spline method) were conducted to explore the exact shape of curve between them. In the fully adjusted model, ln-transformed Mep and BMD showed an independent and positive association (total BMD (β = 0.003, 95% CI (0.001, 0.005), P = 0.01), trunk bone BMD (β = 0.002, 95% CI (0.000, 0.005), P = 0.04), pelvis BMD (β = 0.004, 95% CI (0.001, 0.008), P = 0.02), lumbar spine BMD (β = 0.005, 95% CI (0.001, 0.008), P = 0.01), thoracic spine BMD (β = 0.003, 95% CI (0.001, 0.005), P = 0.02)) and a linear association. Subgroup analysis showed positive association between ln-transformed Mep and BMD. Furthermore, the positive association was significant in females and children aged 12-19 years (P for trend < 0.05). This study is the first study to find evidence demonstrating that exposure to Mep may be positively associated with BMD in children and adolescents aged 8-19 years. Validation of our findings will need further research.

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.

Disruption of type I interferon pathway and reduced production of IFN-α by parabens in virus-infected dendritic cells

BACKGROUND

Parabens are widely used preservatives commonly found in foods, cosmetics, and industrial products. Several studies have examined the effects of parabens on human health owing to widespread and continuous exposure to them in daily life. However, little is known about their immune-regulatory effects.

OBJECTIVE

Here, we aimed to investigate whether methylparaben, ethylparaben, and propylparaben affect the function of dendritic cells (DCs) as the most potent antigen-presenting cells that play a critical role in the initiation of adaptive immune responses.

METHODS

Bone-marrow derived DCs (BMDCs) were treated with three types of parabens (methylparaben, ethylparaben, and propylparaben) for 12 h. Subsequently, the transcriptomic profile was analyzed using RNA sequencing with further gene set enrichment analysis based on commonly regulated differentially expressed genes (DEGs). To test whether parabens suppress the production of type-I interferons (IFN-I) in BMDCs during viral infection, BMDCs or paraben-treated BMDCs were infected with Lymphocytic Choriomeningitis Virus (LCMV) at 10 multiplicity of infection (MOI) and measured the production of IFN-α1.

RESULTS

Transcriptomic analyses revealed that all three types of parabens reduced the transcription levels of genes in virus infection-associated pathways, such as IFN-I responses in BMDCs. Furthermore, parabens considerably reduced IFN-α1 production in the virus-infected BMDCs.

CONCLUSION

Our study is the first to show that parabens may modulate anti-viral immune responses by regulating DCs.

Urinary Paraben Concentrations and Associations with the Periconceptional Urinary Metabolome: Untargeted and Targeted Metabolomics Analyses of Participants from the Early Pregnancy Study

BACKGROUND

Parabens, found in everyday items from personal care products to foods, are chemicals with endocrine-disrupting activity, which has been shown to influence reproductive function.

OBJECTIVES

This study investigated whether urinary concentrations of methylparaben, propylparaben, or butylparaben were associated with the urinary metabolome during the periconceptional period, a critical window for female reproductive function. Changes to the periconceptional urinary metabolome could provide insights into the mechanisms by which parabens could impact fertility.

METHODS

Urinary paraben concentrations were measured in paired pre- and postconception urine samples from 42 participants in the Early Pregnancy Study, a prospective cohort of 221 women attempting to conceive. We performed untargeted and targeted metabolomics analyses using ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry. We used principal component analysis, orthogonal partial least-squares discriminant analysis, and permutation testing, coupled with univariate statistical analyses, to find metabolites associated with paraben concentration at the two time points. Potential confounders were identified with a directed acyclic graph and used to adjust results with multivariable linear regression. Metabolites were identified using fragmentation data.

RESULTS

Seven metabolites were associated with paraben concentration (variable importance to projection score > 1 , false discovery rate-corrected q -value < 0.1 ). We identified four diet-related metabolites to the Metabolomics Standards Initiative (MSI) certainty of identification level 2, including metabolites from smoke flavoring, grapes, and olive oil. One metabolite was identified to the class level only (MSI level 3). Two metabolites were unidentified (MSI level 4). After adjustment, three metabolites remained associated with methylparaben and propylparaben, two of which were diet-related. No metabolomic markers of endocrine disruption were associated with paraben concentrations.

DISCUSSION

This study identified novel relationships between urinary paraben concentrations and diet-related metabolites but not with metabolites on endocrine-disrupting pathways, as hypothesized. It demonstrates the feasibility of integrating untargeted metabolomics data with environmental exposure information and epidemiological adjustment for confounders. The findings underscore a potentially important connection between diet and paraben exposure, with applications to nutritional epidemiology and dietary exposure assessment. https://doi.org/10.1289/EHP12125.

Associations between urinary parabens and lung cancer

Parabens are a family of endocrine-disrupting chemicals. Environmental estrogens may play a vital role in the development of lung cancer. To date, the association between parabens and lung cancer is unknown. Based on the 189 cases and 198 controls recruited between 2018 and 2021 in Quzhou, China, we measured 5 urinary parabens concentrations and examined the association between urinary concentrations of parabens and lung cancer risk. Cases showed significantly higher median concentrations of methyl-paraben (MeP) (2.1 versus 1.8 ng/mL), ethyl-paraben (0.98 versus 0.66 ng/mL), propyl-paraben (PrP) (2.2 versus 1.4 ng/mL), and butyl-paraben (0.33 versus 0.16 ng/mL) than controls. The detection rates of benzyl-paraben were only 8 and 6% in the control and case groups, respectively. Therefore, the compound was not considered in the further analysis. The significant correlation between urinary concentrations of PrP and the risk of lung cancer (odds ratio (OR)_adjusted = 2.22, 95% confidence interval (CI): 1.76, 2.75; P_trend < 0.001) was identified in the adjusted model. In the stratification analysis, we found that urinary concentrations of MeP were significantly associated with lung cancer risk (OR = 1.16, 95% CI: 1.01, 1.27 for the highest quartile group). Besides, comparing the second, third, and fourth quartile groups with the lowest group of PrP, we also observed urinary PrP concentrations associated with lung cancer risk, with the adjusted OR of 1.52 (95% CI: 1.29, 1.65, P_trend = 0.007), 1.39 (95% CI: 1.15, 1.60, P_trend = 0.010), and 1.85 (95% CI: 1.53, 2.30, P_trend = 0.001), respectively. MeP and PrP exposure, reflected in urinary concentrations of parabens, may be positively associated with the risk of lung cancer in adults.

Reduction of daily-use parabens and phthalates reverses accumulation of cancer-associated phenotypes within disease-free breast tissue of study subjects

Estrogenic overstimulation is carcinogenic to the human breast. Personal care products (PCPs) commonly contain xenoestrogens (XE), such as parabens and phthalates. Here, we identified the adverse effects of persistent exposure to such PCPs directly within human estrogen responsive breast tissue of subjects enrolled in a regimen of reduced XE use (REDUXE). Pre- and post-intervention fine needle aspirates (FNAs) of the breast were collected from healthy volunteers who discontinued the use of paraben and phthalate containing PCPs over a 28 d period. Based on high-dimensional gene expression data of matched FNA pairs of study subjects, we demonstrate a striking reversal of cancer-associated phenotypes, including the PI3K-AKT/mTOR pathway, autophagy, and apoptotic signaling networks within breast cells of REDUXE compliant subjects. These, and other altered phenotypes were detected together with a significant reduction in urinary parabens and phthalate metabolites. Moreover, in vitro treatment of paired FNAs with 17β-estradiol (E2), displayed a 'normalizing' impact of REDUXE on gene expression within known E2-modulated pathways, and on functional endpoints, including estrogen receptor alpha: beta ratio, and S-phase fraction of the cell cycle. In a paradigm shifting approach facilitated by community-based participatory research, REDUXE reveals unfavorable consequences from exposure to XEs from daily-use PCPs. Our findings illustrate the potential for REDUXE to suppress pro-carcinogenic phenotypes at the cellular level towards the goal of breast cancer prevention.

Urinary phenol concentrations and fecundability and early pregnancy loss

STUDY QUESTION

Are urinary phenol concentrations of methylparaben, propylparaben, butylparaben, triclosan, benzophenone-3, 2,4-dichlorophenol or 2,5-dichlorophenol associated with fecundability and early pregnancy loss?

SUMMARY ANSWER

2,5-dichlorophenol concentrations were associated with an increased odds of early pregnancy loss, and higher concentrations of butylparaben and triclosan were associated with an increase in fecundability.

WHAT IS KNOWN ALREADY

Phenols are chemicals with endocrine-disrupting potential found in everyday products. Despite plausible mechanisms of phenol reproductive toxicity, there are inconsistent results across few epidemiologic studies examining phenol exposure and reproductive function in non-fertility treatment populations.

STUDY DESIGN, SIZE, DURATION

Specimens and data were from the North Carolina Early Pregnancy Study prospective cohort of 221 women attempting to conceive naturally from 1982 to 1986. This analysis includes data from 221 participants across 706 menstrual cycles, with 135 live births, 15 clinical miscarriages and 48 early pregnancy losses (before 42 days after the last menstrual period).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants collected daily first-morning urine specimens. For each menstrual cycle, aliquots from three daily specimens across the cycle were pooled within individuals and analyzed for phenol concentrations. To assess sample repeatability, we calculated intraclass correlation coefficients (ICCs) for each phenol. We evaluated associations between phenol concentrations from pooled samples and time to pregnancy using discrete-time logistic regression and generalized estimating equations (GEE), and early pregnancy loss using multivariable logistic regression and GEE.

MAIN RESULTS AND THE ROLE OF CHANCE

ICCs for within-person variability across menstrual cycles in pooled phenol concentrations ranged from 0.42 to 0.75. There was an increased odds of early pregnancy loss with 2,5-dichlorophenol concentrations although the CIs were wide (5th vs 1st quintile odds ratio (OR): 4.79; 95% CI: 1.06, 21.59). There was an increased per-cycle odds of conception at higher concentrations of butylparaben (OR: 1.62; 95% CI: 1.08, 2.44) and triclosan (OR: 1.49; 95% CI: 0.99, 2.26) compared to non-detectable concentrations. No associations were observed between these endpoints and concentrations of other phenols examined.

LIMITATIONS, REASONS FOR CAUTION

Limitations include the absence of phenol measurements for male partners and a limited sample size, especially for the outcome of early pregnancy loss, which reduced our power to detect associations.

WIDER IMPLICATIONS OF THE FINDINGS

This study is the first to use repeated pooled measures to summarize phenol exposure and the first to investigate associations with fecundability and early pregnancy loss. Within-person phenol concentration variability underscores the importance of collecting repeated samples for future studies. Exposure misclassification could contribute to differences between the findings of this study and those of other studies, all of which used one urine sample to assess phenol exposure. This study also contributes to the limited literature probing potential associations between environmental exposures and early pregnancy loss, which is a challenging outcome to study as it typically occurs before a pregnancy is clinically recognized.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the National Institute of Environmental Health Sciences of the National Institutes of Health (award number F31ES030594), the Intramural Research Program of the National Institutes of Health, the National Institute of Environmental Health Sciences (project numbers ES103333 and ES103086) and a doctoral fellowship at the Yale School of Public Health. The authors declare they have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Comprehensive monitoring of a special mixture of prominent endocrine disrupting chemicals in human urine using a carefully adjusted hydrolysis of conjugates

Many xenobiotics were identified as possible endocrine disruptors during the last decades. Structural analogy of these substances to natural hormones may lead to agonists or antagonists of hormone receptors. For a comprehensive human biomonitoring of such substances, we developed a simple, reliable, and highly sensitive method for the simultaneous monitoring of the parameters bisphenol A, triclosan, methylparaben, ethylparaben, propylparaben, butylparaben, benzophenone-1, benzophenone-3, 3,5,6-trichloropyridin-2-ol, p-nitrophenol, genistein, and daidzein in urine. Thereby, optimization of the enzymatic hydrolysis and the use of β-glucuronidase from E. coli K12 as well as sulfatase from Aerobacter aerogenes ensures the acquisition of intact analytes without cleavage of ester bonds among parabens. Validation of the method revealed limits of detection between 0.02 and 0.25 µg/L as well as limits of quantification between 0.08 and 0.83 µg/L. Thereby, the use of analyte-free surrogate matrix for calibration and control material influenced the sensitivity of the procedure positively. Furthermore, excellent precision in and between series was observed. Good absolute and relative recoveries additionally proved the robustness of the multimethod. Thus, the procedure can be applied for exploring the exposome to these prominent endocrine disruptors in the general population.

Chemical vs. natural toothpaste: which formulas for which properties? A scoping review

Introduction

The proliferation of the oral care industry has made it more challenging for shoppers to zero in on the best possible toothpaste for their preventative requirements. It also makes the toothpaste’s various components safer.

Objective

The researchers set out to evaluate the state of information about the biological properties and cytotoxicity of adult toothpaste so that they might make some informed recommendations.

Methods

A scoping review of research published between 2015 and 2020 according to PRISMA guidelines was performed.

Results

In vitro clinical trials account for 44% of the papers, in vivo clinical trials for 25%, systematic reviews for 19%, and metaanalyses for 12%. They have active chemical components that have been shown to be antimicrobial, anti-inflammatory, or desensitizing. Herbal toothpaste has these characteristics and is very secure to use. Toothpaste with sodium lauryl sulfate has been found to be harmful.

Conclusions

Scientists have investigated the biological effects of a wide range of chemically active compounds and plant extracts. Herbal toothpaste, it has been discovered, is both efficient and secure. Companies making toothpaste should be required to clearly label the product’s qualities, active ingredients, and potentially harmful ingredients on the packaging.

Oxidative stress responses after exposure to triclosan sublethal concentrations: an integrated biomarker approach with a native (Corydoras paleatus) and a model fish species (Danio rerio)

Triclosan (TCS) is a synthetic broad-spectrum antimicrobial agent commonly used world-wide in a range of personal care and sanitizing products detected frequently in aquatic ecosystems. The aim of this study was to examine biochemical markers responses triggered by TCS in Danio rerio and in a native South American fish species (Corydoras paleatus). Further, an integrated approach comparing both test fish species was undertaken. These fish organisms were exposed to 100 or 189 µg TCS/L for 48 h. The activities of catalase (CAT), glutathione-s-transferase (GST), superoxide dismutase (SOD), and lipid peroxidation levels (LPO) and total antioxidant capacity against peroxyl radicals (ACAP) were determined in liver, gills, and brain. Acetylcholinesterase activity (AChE) was measured in the brain. Multivariate analysis showed that the most sensitive hepatic parameters were activities of GST and SOD for C. paleatus while LPO levels were for D. rerio. In gills the same parameters were responsive for C. paleatus but CAT in D. rerio. ACAP and GST activity were responsive parameters in brain of both species. Integrated biomarker responses (IBR) index demonstrated similar trends in both species suggesting this parameter might serve as a useful tool for quantification of integrated responses induced by TCS.

Determination of contamination levels for multiple endocrine disruptors in hair from a non-occupationally exposed population living in Liege (Belgium)

Today, the interest in hair as alternative matrix for human biomonitoring of environmental pollutants has increased, but available data on chemical levels in hair remain scarce. In this study, the measurement of 2 bisphenols (A and S), 3 parabens (methyl-, ethyl- and propylparabens) and 8 perfluroralkyl compounds (PFCs) namely perfluoroctanesulfonate (PFOS), perfluorohexanesulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluroroheptanoic acid (PFHpA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA) was carried out, using a thoroughly validated UPLC-MS/MS method, in the hair from 114 adults living in Liege (Belgium) and surrounding areas. The most frequently quantified compounds in the population were: bisphenol S (97.4%, median = 31.9 pg·mg^-1), methylparaben (94.7%, median = 28.9 pg·mg^-1), bisphenol A (93.9%, median = 46.6 pg·mg^-1), ethylparaben (66.7%, median = 5.2 pg·mg^-1), propylparaben (54.8%, median = 16.4 pg·mg^-1) and PFOA (46.4%, median < 0.2 pg·mg^-1). The other PFCs were detected only in few samples although current exposure of the Belgian population to PFCs was previously demonstrated using blood analyses. Nonparametric statistical analyses were performed to evaluate the influence of gender, hair treatments and hair length, but no significant difference was observed. Only age was positively correlated with the propylparaben contamination. Although blood seems to remain more suitable for PFCs exposure assessment, the results of this study suggest that hair can be an appropriate matrix for biomonitoring of organic pollutants such as parabens or bisphenols.

Natural Food Colorants and Preservatives: A Review, a Demand, and a Challenge

The looming urgency of feeding the growing world population along with the increasing consumers' awareness and expectations have driven the evolution of food production systems and the processes and products applied in the food industry. Although substantial progress has been made on food additives, the controversy in which some of them are still shrouded has encouraged research on safer and healthier next generations. These additives can come from natural sources and confer numerous benefits for health, beyond serving the purpose of coloring or preserving, among others. As limiting factors, these additives are often related to stability, sustainability, and cost-effectiveness issues, which justify the need for innovative solutions. In this context, and with the advances witnessed in computers and computational methodologies for in silico experimental aid, the development of new safer and more efficient natural additives with dual functionality (colorant and preservative), for instance by the copigmentation phenomena, may be achieved more efficiently, circumventing the current difficulties.

Insights into the spatiotemporal occurrence and mixture risk assessment of household and personal care products in the waters from rivers to Laizhou Bay, southern Bohai Sea

Household and personal care products (HPCPs) are a kind of contaminants closely related to daily life, capturing worldwide concern. To our knowledge, this is the first attempt focusing on the spatiotemporal occurrence and mixture risk of HPCPs in the waters from rivers to Laizhou Bay. Nine HPCPs were quantitated in 216 water samples gathered from Laizhou Bay and its adjacent rivers in 2018, 2019, and 2021 to reveal the spatiotemporal occurrence and mixture ecological risks in Laizhou Bay. Eight HPCPs were detected with detection frequencies ranging from 74% to 100%. The total concentrations were in the ranges 105-721 ng L^-1 in river water and 51.3-332 ng L^-1 in seawater. The HPCPs were dominated by p-hydroxybenzoic and triclosan, which together contributed over 75% of the total HPCPs. The average level of the total HPCP concentration in the summer of 2018 (96.1 ng L^-1) was slightly exceed that in the spring of 2019 (91.6 ng L^-1), which is associated with the higher usage of HPCPs and enhanced tourism during summer. However, the highest total concentrations were found in spring of 2021 (124 ng L^-1 in average), which was attribute to a higher level of methylparaben, a predominant paraben used as preservatives in commercial pharmaceuticals of China. Influenced by riverine inputs and ocean currents, higher HPCP concentrations in Laizhou Bay were found nearby the estuary of Yellow River and the southern part of the bay. Triclosan should be given constant concern considering its medium to high risks (RQ > 0.1) in nearly 80% of the water samples. The cumulative risk assessment in two approaches revealed that HPCP mixtures generally elicit medium or high risk to three main aquatic taxa. Considering the worldwide outbreak of COVID-19, the levels and risks of multiple HPCPs in natural waters requires constant attention in future studies.

Minireview: Parabens Exposure and Breast Cancer

There is increasing recognition that environmental exposure to chemicals, such as endocrine-disruptive chemicals (EDCs), contributes to the development of breast cancer. Parabens are a group of EDCs commonly found in personal care products, foods, and pharmaceuticals. Systemic exposure to parabens has been confirmed by the ubiquitous detection of parabens in human blood and urine samples. Although evidence from in vivo and epidemiological studies linking parabens exposure to breast cancer is limited, the current evidence suggests that parabens may negatively interfere with some endocrine and intracrine targets relevant to breast carcinogenesis. So far, most studies have focused on a single paraben's effects and the direct modulating effects on estrogen receptors or the androgen receptor in vitro. Recent studies have revealed that parabens can modulate local estrogen-converting enzymes, 17β-hydroxysteroid dehydrogenase 1 and 2 and increase local estrogen levels. Also, parabens can crosstalk with the human epidermal growth factor receptor 2 (HER2) pathway and work with ER signaling to increase pro-oncogenic c-Myc expression in ER+/HER2+ breast cancer cells. Future studies investigating paraben mixtures and their crosstalk with other EDCs or signaling pathways both in vitro and in vivo in the context of breast cancer development are warranted.

Concentrations of bisphenols, parabens, and benzophenones in human breast milk: A systematic review and meta-analysis

BACKGROUND

Breast milk is the main source of nutrition for infants but may be responsible for their exposure to environmental chemicals, including endocrine-disrupting chemicals.

AIM

To review available evidence on the presence and concentrations of bisphenols, parabens (PBs), and benzophenones (BPs) in human milk and to explore factors related to exposure levels.

METHODS

A systematic review was carried out using Medline, Web of Science, and Scopus databases, conducting a comprehensive search of peer-reviewed original articles published during the period 2000-2020, including epidemiological and methodological studies. Inclusion criteria were met by 50 studies, which were compiled by calculating weighted detection frequencies and arithmetic mean concentrations of the chemicals. Their risk of bias was assessed using the ROBINS-I checklist.

RESULTS

Among the 50 reviewed studies, concentrations of bisphenols were assessed by 37 (74.0%), PBs by 21 (42.0%), and BPs by 10 (20.0%). Weighted detection frequencies were 63.6% for bisphenol-A (BPA), 27.9-63.4% for PBs, and 39.5% for benzophenone-3 (BP-3). Weighted mean concentrations were 1.4 ng/mL for BPA, 0.2-14.2 ng/mL for PBs, and 24.4 ng/mL for BP-3. Mean concentrations ranged among studies from 0.1 to 3.9 ng/mL for BPA, 0.1 to 1063.6 ng/mL for PBs, and 0.5 to 72.4 ng/mL for BP-3. The highest concentrations of BPA and PBs were reported in samples from Asia (versus America and Europe). Higher BPA and lower methyl-paraben concentrations were observed in samples collected after 2010. Elevated concentrations of these chemicals were associated with socio-demographic and lifestyle factors in eight studies (16.0%). Two epidemiological studies showed moderate/serious risk of bias.

CONCLUSIONS

This systematic review contributes the first overview of the widespread presence and concentrations of bisphenols, PBs, and BPs in human breast milk, revealing geographical and temporal variations. The methodological heterogeneity of published studies underscores the need for well-conducted studies to assess the magnitude of exposure to these chemicals from human milk.

The implication of parabens in cosmetics and cosmeceuticals: advantages and limitations

Cosmetics, cosmeceuticals, and variable healthcare products used parabens, among other excipients, for their preservative and antimicrobial activities. Paraben derivatives exhibit distinguished physiochemical properties that enable them to be compatible with the formulation of cosmetic agents in different dosage forms. In addition to their potency and efficacy, parabens are economically efficient as they have low manufacturing costs. Despite the desirable characteristics, the safety of parabens use is controversial after detecting these chemicals in various biological tissues after repetitive and long-term use of formulations containing them. The use of parabens drew public health attention after scientific reports linked skin exposure to parabens with health issues, in particular, breast cancer. In response, worldwide authorities set regulations for the allowance concentrations of paraben to be used in variable cosmetic products.

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.

Biogenic Silver Nanoparticles from Iris tuberosa as Potential Preservative in Cosmetic Products

Biogenic-silver nanoparticles emerge as new nanosilver platforms that allow us to obtain silver nanoparticles via "green chemistry". In our study, biogenic-silver nanoparticles were obtained from Iris tuberosa leaf extract. Nanoparticles were characterized by a UV-vis spectroscopy, dynamical light scattering technique. The transmission electron microscope revealed spheric and irregular nanoparticles with 5 to 50 nm in diameter. Antimicrobial properties were evaluated against typical microbial contaminants found in cosmetic products, showing high antimicrobial properties. Furthermore, natural moisturizing cream was formulated with biogenic-silver nanoparticles to evaluate the preservative efficiency through a challenge test, indicating its promising use as preservative in cosmetics.

Parental preconception exposure to phenol and phthalate mixtures and the risk of preterm birth

BACKGROUND

Parental preconception exposure to select phenols and phthalates was previously associated with increased risk of preterm birth in single chemical analyses. However, the joint effect of phenol and phthalate mixtures on preterm birth is unknown.

METHODS

We included 384 female and 211 male (203 couples) participants seeking infertility treatment in the Environment and Reproductive Health (EARTH) Study who gave birth to 384 singleton infants between 2005 and 2018. Mean preconception urinary concentrations of bisphenol A (BPA), parabens, and eleven phthalate biomarkers, including di(2-ethylhexyl) phthalate (DEHP) metabolites, were examined. We used principal component analysis (PCA) with log-Poisson regression and Probit Bayesian Kernel Machine Regression (BKMR) with hierarchical variable selection to examine maternal and paternal phenol and phthalate mixtures in relation to preterm birth. Couple-based BKMR model was fit to assess couples' joint mixtures in relation to preterm birth.

RESULTS

PCA identified the same four factors for maternal and paternal preconception mixtures. Each unit increase in PCA scores of maternal (adjusted Risk Ratio (aRR): 1.36, 95%CI: 1.00, 1.84) and paternal (aRR: 1.47, 95%CI: 0.90, 2.42) preconception DEHP-BPA factor was positively associated with preterm birth. Maternal and paternal BKMR models consistently presented the DEHP-BPA factor with the highest group Posterior Inclusion Probability (PIP). BKMR models further showed that maternal preconception BPA and mono(2-ethyl-5-hydroxyhexyl) phthalate, and paternal preconception mono(2-ethylhexyl) phthalate were positively associated with preterm birth when the remaining mixture components were held at their median concentrations. Couple-based BKMR models showed a similar relative contribution of paternal (PIP: 61%) and maternal (PIP: 77%) preconception mixtures on preterm birth. We found a positive joint effect on preterm birth across increasing quantiles of couples' total mixture concentrations.

CONCLUSION

In this prospective cohort of subfertile couples, maternal BPA and DEHP, and paternal DEHP exposure before conception were positively associated with preterm birth. Both parental windows jointly contributed to the outcome. These results suggest that preterm birth may be a couple-based pregnancy outcome.

Parabens in personal care products and indoor dust from Hanoi, Vietnam: Temporal trends, emission sources, and non-dietary exposure through dust ingestion

The occurrence of seven typical parabens was investigated in several types of personal care products (PCPs) sold at supermarkets and in indoor dust samples collected from houses, laboratories, and medical stores in Hanoi, Vietnam. Parabens were frequently detected in PCPs regardless of the paraben indication in their ingredient labels. However, concentrations of parabens in labeled products (median 3280; range 1370-5610 μg/g) were much higher than those found in non-labeled products (69.4; not detected - 356 μg/g). Parabens were also measured in indoor dust samples of this study at elevated concentrations, ranging from not detected to 1650 (median 286 ng/g). Levels of parabens in the indoor dust samples collected in 2019 decreased in the order: house > medical store > laboratory dust, however, the difference was not statistically significant. Interestingly, levels of parabens in Vietnamese house dust exhibited an increasing trend over time, for example, mean/median concentrations of parabens in house dust samples collected in 2014, 2017, and 2019 were 245/205, 310/264, and 505/379 ng/g, respectively. Methylparaben was found at the highest frequency and concentrations in both PCPs and indoor dust samples. Mean exposure doses of total parabens through dust ingestion were estimated to be 2.02, 1.61, 0.968, 0.504, and 0.192 ng/kg-bw/d for infants, toddlers, children, teenagers, and adults, respectively. Further studies on the distribution, emission behavior, potential sources, and negative impacts of parabens in different environmental media in Vietnam are needed.

Parabens enhance the calcium-dependent testicular mitochondrial permeability transition: Their relevance on the reproductive capacity in male animals

Parabens, alkyl ester derivatives from p-hydroxybenzoic acid, are extensively used as antimicrobial preservatives. Nonetheless, due to its widespread and massive employment, several studies highlighted the association between parabens and alterations in the reproductive system. This study aimed to relate the adverse effect of the most commonly used parabens in testis mitochondria with male fertility. From all the parabens used, propyl and butyl were the ones that most negatively decreased the respiratory control ratio. In the case of butyl, inhibitions of 20% and 60% were observed, respectively, at the lowest and highest concentration, when compared to the control group. The membrane potential was only significantly affected by propyl (14%) and butyl (31%), and at a concentration of 250 µM. Succinate dehydrogenase, cytochrome c oxidase, and ATPase activities showed a nonsignificant decrease. Cytochrome c reductase, on the other hand, showed statistically significant inhibitions for both propyl (56%) and butylparaben (55%). The susceptibility to the mitochondrial permeability transition pore (MPTP) opening was increased by all parabens, although this increase was markedly significant for propyl and butyl. These results show that the susceptibility of mitochondria to parabens is dependent on the alkyl chain length and parabens hydrophobicity, and the main mitochondrial target is Complex II-III and MPTP. Hence, this study demonstrates the contribution of parabens exposition to the inhibition of testis mitochondrial function and their putative noxious effect on the male reproductive system.

Effects of prenatal exposure to five parabens on neonatal thyroid function and birth weight: Evidence from SMBCS study

BACKGROUND

Parabens, suspected as endocrine-disrupting chemicals, are nearly ubiquitous in the human body and exposure to these chemicals during pregnancy may disrupt thyroid hormones homeostasis and even affect fetal growth, although the impacts are still unclear.

OBJECTIVES

We aimed to estimate associations of maternal urinary paraben concentrations with cord serum thyroid hormones and birth weight.

METHODS

A subset of 437 mother-newborn pairs were included from a prospective birth cohort with five parabens quantified in maternal urine and seven thyroid function indicators measured in cord serum samples. Multivariable linear regression models and elastic net regression (ENR) models were applied to explore associations between individual and mixtures of prenatal urinary paraben concentrations and thyroid hormones and birth weight, respectively.

RESULTS

Maternal urinary ethyl-paraben (EtP) concentrations were associated with increased cord serum total triiodothyronine levels (TT3) [percent change: 1.51%; 95% confidence interval (CI): 0.20%, 2.74%; p=0.017]. Urinary propyl-paraben (PrP) levels predicted higher thyroid peroxidase antibodies (percent change: 4.19%, 95%CI: 0.20%, 8.44%; p=0.041). Maternal urinary EtP and butyl-paraben (BuP) concentrations were significantly positively associated with birth weight [regression coefficient, (β)=40.9g, 95%CI: 3.99, 76.6; p=0.030; β=62.1g, 95%CI: 8.70, 115; p=0.023, for EtP and BuP, respectively]. In sex-stratified analyses, positive relationship between EtP levels and birth weight was observed in boys. Urinary EtP concentrations predicted higher TT3 levels in cord serum samples, assessing parabens as a chemical mixture with ENR models.

CONCLUSIONS

Prenatal exposure to parabens may affect thyroid hormone indicators with increased serum TT3 levels and associate with higher birth weight, especially in boys. The underlying biological mechanisms and effects of prenatal paraben exposures on disruption of thyroid function homeostasis and potential impacts of childhood growth and development needed to be further investigated.

Association of placental concentrations of phenolic endocrine disrupting chemicals with cognitive functioning in preschool children from the Environment and Childhood (INMA) Project

Developmental exposure to bisphenol A (BPA) and other phenolic endocrine disrupting chemicals (EDCs) may affect child neurodevelopment, but data on the effects of prenatal exposure to phenols on cognitive function remain sparse. Our aim was to examine the association of placental concentrations of several phenolic EDCs, including BPA, parabens (PBs), and benzophenones (BzPs), with cognitive development in preschool children from the Environment and Childhood (INMA) Project in Spain. Concentrations of BPA, four PBs (methylparaben [MePB], ethylparaben [EtPB], propylparaben [PrPB], and butylparaben [BuPB]), and six BzPs (BzP-1, BzP-2, BzP-3, BzP-6, BzP-8, and 4-hydroxybenzophenone [4-OH-BzP]) were measured in 490 placenta samples randomly selected from five INMA cohorts collected between 2000 and 2008. Neuropsychological assessment of cognitive and motor function was performed with the McCarthy Scales of Children's Abilities (MSCA) at the age of 4-5 years. Associations were assessed in a sub-sample of 191 mother-child pairs using linear and logistic regression models adjusted for confounding factors. PB compounds were detected in more than 71% of placentas, BPA in 62%, 4-OH-BzP in 50%, and the remaining BzPs in <9% of the samples. Because of the low detection frequency of BzP compounds, only 4-OH-BzP was included in the exposure-outcome analyses. After adjustment for confounders, BPA was associated with greater odds of scoring lower (below the 20th percentile) in the verbal (third vs. first exposure tertile: odds ratio [OR] = 2.78, 95% confidence interval [CI] = 1.00; 5.81, p-trend = 0.05) and gross motor (detected vs. undetected: OR = 1.75, 95%CI = 1.06; 9.29) areas, and these associations were only significant for boys. Regarding PB compounds, PrPB was associated with lower scores in memory (detected vs. undetected: β = -4.96, 95%CI = -9.54; -0.31), span memory (OR = 2.50, 95%CI = 0.95; 6.92 and 2.71, 95%CI = 0.97; 6.64, respectively for second and third tertiles, p-trend = 0.03), and motor function (β = -5.15, 95%CI = -9.26; -0.01 for third vs. first exposure tertile, p-trend = 0.04). EtPB and total PBs concentrations in the second tertile were also associated with poorer visual function of posterior cortex and worse quantitative performance, respectively, but linear trends were not statistically significant. The associations of BPA and PrPB with poorer verbal, memory, and motor skills are novel observations that warrant further attention. Larger prospective studies are required to confirm whether prenatal exposure to BPA and other phenolic EDCs is associated with impaired cognitive development.

Methylparaben in meconium and risk of maternal thyroid dysfunction, adverse birth outcomes, and Attention-Deficit Hyperactivity Disorder (ADHD)

BACKGROUND

Parabens, which are used as a preservative in foods and personal care products, are detected in nearly 100% of human urine samples. Exposure to parabens is associated with DNA damage, male infertility, and endocrine disruption in adults, but the effects of prenatal exposure are unclear. In part, this is due to inadequate assessment of exposure in maternal urine, which may only reflect maternal rather than fetal exposure. To address this gap, we examined the association of prenatal methylparaben measured in meconium with preterm birth, gestational age, birthweight, maternal thyroid hormones, and child Attention-Deficit Hyperactivity Disorder (ADHD) at 6-7 years.

DESIGN

Data come from the GESTation and the Environment (GESTE) prospective observational pregnancy cohort in Sherbrooke, Quebec, Canada. Participants were 345 children with data on ADHD among 394 eligible pregnancies in women age ≥18 years with no known thyroid disease before pregnancy and meconium collected at delivery. Methylparaben was measured in meconium. Birthweight, gestational age, and maternal thyroid hormones at <20 weeks gestation were measured at the Centre Hospitalier Universitaire de Sherbrooke. Preterm birth was defined as vaginal birth before the 37th week of gestation. Physician diagnosis of ADHD was determined at a scheduled cohort follow-up when children were 6-7 years old or from medical records. Associations between meconium methylparaben and outcomes were estimated with logistic and linear regressions weighted on the inverse probability of exposure to account for potential confounders, including child sex, familial income, maternal education, pre-pregnancy body mass index, age, and smoking and alcohol consumption during pregnancy.

RESULTS

Methylparaben was detected in 65 meconium samples (19%), 33 children were diagnosed with ADHD (10%), and 13 children were born preterm (4%). Meconium methylparaben was associated with preterm birth (odds ratio [OR] = 4.81; 95% CI [2.29, 10.10]), decreased gestational age (beta [β] = -0.61 weeks; 95% CI [-0.93, -0.29]) and birthweight (β = -0.12 kg; 95% CI [-0.21, -0.03]), altered maternal TSH (relative concentration [RC] = 0.76; 95% CI [0.58, 0.99]), total T3 (RC = 0.84; 95% CI [0.75, 0.96]) and total T4 (RC = 1.10; 95% CI [1.01, 1.19]), maternal hypothyroxinemia (OR = 2.50, 95% CI [1.01, 6.22]), and child ADHD at age of 6-7 (OR = 2.33, 95% CI [1.45, 3.76]). The effect of meconium methylparaben on ADHD was partially mediated by preterm birth (20% mediation) and birthweight (13% mediation).

CONCLUSIONS

Meconium methylparaben was associated with preterm birth, decreased gestational age and birthweight, maternal thyroid hormone dysfunction, and child ADHD. Parabens are a substantial health concern if causally related to these adverse outcomes.

Menstrual blood concentrations of parabens and benzophenones and related factors in a sample of Spanish women: An exploratory study

AIM

To evaluate concentrations of parabens (PBs) and benzophenones (BzPs) in menstrual blood and explore related sociodemographic/lifestyle factors, and to compare between menstrual and peripheral blood concentrations in a subset of samples.

MATERIAL AND METHODS

Concentrations of 4 PBs [methyl- (MeP), ethyl- (EtP), propyl- (PrP) and butyl-paraben (BuP)] and 6 BzPs [BzP-1, BzP-2, BzP-3, BzP-6, BzP-8 and 4-OH-BzP] were determined in menstrual blood from 57 women and in both menstrual and peripheral blood samples from 12 women, all healthy Spanish women of reproductive age. Socio-demographic characteristics and lifestyle habits [diet and use of cosmetics and personal care products (PCPs)] were gathered using an online questionnaire. Spearman correlation analysis was performed to examine the relationship between menstrual and peripheral blood concentrations, while multivariable linear regression was used to identify potential explanatory variables for menstrual PB and BzP concentrations.

RESULTS

Globally, all menstrual blood samples had detectable levels of ≥3 compounds, and 52.6% of the samples contained ≥6 compounds. MeP, PrP, and BzP-3 were the most frequently detected compounds (detection frequencies >90.0%), with median concentrations of 1.41, 0.63, and 1.70 ng/mL of menstrual blood, respectively. Age, the use of PCPs, and consumption of some food items (meat, pasta, cheese, or dairy products) were related to the menstrual blood concentrations of some PBs/BzPs. Serum:menstrual blood ratios of PBs/BzPs ranged from 1.7 to 3.6, with no inter-matrix correlations.

CONCLUSIONS

This study reveals, to our knowledge for the first time, the widespread presence of several PBs and BzPs in intimate contact with gynecological tissues, although their concentrations in menstrual blood were not correlated with those in peripheral blood from the same women. These results shed light on the information provided by the menstrual blood as a potential matrix for characterizing exposure to PBs and BzPs, whose consequences for women's reproductive health need to be addressed.

The Beast of Beauty: Environmental and Health Concerns of Toxic Components in Cosmetics

Cosmetic products are used in large quantities across the world. An increasing number of chemical compounds are being added to the formulation of cosmetic products as additives, fragrances, preservatives, stabilizers, surfactants, dye and shine to potentiate their quality, property and shelf life. Owing to their widespread use, active residues of cosmetic products are continuously introduced into the environment in several ways. Many of these chemicals are bioactive and are characterized by potential bioaccumulation ability and environmental persistence, thus exerting a major risk to humans and the health of ecosystems. Hence, the indiscriminate consumption of cosmetics may present a looming issue with significant adverse impacts on public health. This review intends to spotlight a current overview of toxic ingredients used in formulating cosmetics such as parabens, triclosan, benzalkonium chloride, 1,4-dioxane, plastic microbeads, formaldehyde, diazolidinyl urea, imidazolidinyl urea, sunscreen elements (organic and inorganic UV filters) and trace metals. Specific focus is given to illustrate the biological risks of these substances on human health and aquatic system in terms of genotoxicity, cytotoxicity, neurotoxicity mutagenicity, and estrogenicity. In addition to conclusive remarks, future directions are also suggested.

An insight into toxicity and human-health-related adverse consequences of cosmeceuticals - A review

In recent years, the use of cosmeceutical-based personal care and beauty products has ever increased, around the world. Currently, an increasing number of compounds are being assimilated in the formulation of cosmetic products as preservatives, fragrances, surfactants, etc. to intensify the performance, quality, value, and lifespan of cosmetics. Nevertheless, many of these chemical additives pose toxic effects to the human body, exhibiting health risks from a mild hypersensitivity to life-threatening anaphylaxis or lethal intoxication. Therefore, the indiscriminate application of cosmeceuticals has recently become a mounting issue confronting public health. The present review focuses on exposure to a large variety of toxic substances used in cosmetic formulations such as 1,4-dioxane formaldehyde, paraformaldehyde, benzalkonium chloride, imidazolidinyl urea, diazolidinyl urea, trace heavy metals, parabens derivatives, phthalates, isothiazolinone derivatives (methylchloroiso-thiazolinone, and methylisothiazolinone), methyldibromo glutaronitrile, and phenoxy-ethanol. The biological risks related to these substances that they can pose to human health in terms of cytotoxicity, genotoxicity, mutagenicity, neurotoxicity oestrogenicity or others are also discussed. Researchers from academia, consultancy firms, governmental organizations, and cosmetic companies should carry out further progress to keep updating the consumers regarding the dark-sides, and health-related harmful apprehensions of cosmetics. In addition, the industry-motivated initiatives to abate environmental impact through green, sustainable and eco-friendly product development grasp significant perspective.

Concentrations of bisphenol A and parabens in socks for infants and young children in Spain and their hormone-like activities

BACKGROUND

Little information is available on the content of bisphenol A (BPA) and other endocrine-disrupting chemicals (EDCs) such as parabens in infant textiles and clothes.

OBJECTIVES

1) To determine the concentrations of BPA and parabens in socks for infants and young children purchased in Spain, 2) to assess the (anti-)estrogenicity and (anti-)androgenicity of extracts from the socks, and 3) to estimate dermal exposure doses to these chemicals.

METHODS

Thirty-two pairs of socks for infants and young children (1-48 months) were purchased from 3 stores in Granada (Spain). Textile material was cut from the foot, toe, and leg of each sock (n = 96 samples) for chemical analysis. Hormone-like activities were determined in foot sections (n = 32 samples) by using the E-Screen assay for (anti-)estrogenicity and PALM luciferase assay for (anti-)androgenicity.

RESULTS

BPA was present in 90.6% of samples at concentrations ranging from <0.70 to 3736 ng/g. BPA levels were around 25-fold higher in socks from store 1, which had a higher cotton content compared to stores 2 and 3. Ethyl-paraben was found in 100% of samples, followed by methyl-paraben (81.0%), and propyl-paraben (43.7%). No butyl-paraben was detected in any sample. Estrogenic activity was detected in 83.3% of socks from store 1 (range = 48.2-6051 pM E₂eq/g) but in only three socks from stores 2 and 3. Anti-androgenic activity was detected in six of the 32 socks studied (range = 94.4-2989 μM Proceq/g), all from store 1. Estimated dermal exposure to BPA was higher from socks for children aged 36-48 months (median = 17.6 pg/kg/day), and dermal exposure to parabens was higher from socks for children aged 24-36 months (median = 0.60 pg/kg/day).

DISCUSSION

This is the first report in Europe on the wide presence of BPA and parabens in socks marketed for infants and children. BPA appears to contribute to the hormone-like activity observed in sock extracts.

Preparation and Physicochemical Stability of Liquid Oral Dosage Forms Free of Potentially Harmful Excipient Designed for Pediatric Patients

Dexamethasone, hydrochlorothiazide, spironolactone, and phenytoin are commonly used in neonates, but no age-appropriate formulation containing these active pharmaceutical ingredients (APIs) is commercially available. Thus, pharmaceutical compounding of the liquid oral dosage form is required to enable newborn administration. A problem common to the compounded preparations described in the literature is that they include potentially harmful excipients (PHEs). Therefore, the aim of this study was to evaluate the feasibility of compounding oral liquid dosage forms free of PHE, containing dexamethasone, hydrochlorothiazide, phenytoin, or spironolactone and to assess their physicochemical stability. Due to the poor water solubility of the targeted APIs, oral suspensions were compounded using Syrspend® SF-PH4 Dry, a suspending vehicle free of PHE. Four HPLC coupled to UV spectrometry (HPLC-UV) stability-indicating methods were developed and validated according to international guidelines to assay the strength of the targeted APIs. Whatever storage condition was used (5 ± 3 °C or 22 ± 4 °C), no significant degradation of API occurred in compounded oral suspensions. Overall, the results attest to the physical and chemical stability of the four oral liquid dosage forms over 60 days under regular storage temperatures. Finally, the use of the proposed oral suspensions provides a reliable solution to reduce the exposure of children to potentially harmful excipients.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Personal care product use as a predictor of urinary concentrations of certain phthalates, parabens, and phenols in the HERMOSA study

Use of personal care products, such as makeup, soaps, and sunscreen, may expose adolescent girls to potential endocrine disruptors, including phthalates, parabens, and other phenols. We evaluated the relationship between recent self-reported personal care product use and concentrations for urinary metabolites of phthalates, parabens, triclosan, and benzophenone-3 (BP-3) in 100 Latina adolescents. Girls who reported using makeup every day vs. rarely/never had higher urinary concentrations of monoethyl phthalate (MEP) (102.2 ng/mL vs. 52.4 ng/mL, P-value: 0.04), methyl paraben (MP) (120.5 ng/mL vs. 13.4 ng/mL, P-value < 0.01), and propyl paraben (PP) (60.4 ng/mL vs. 2.9 ng/mL, P-value < 0.01). Girls who reported recent use of specific makeup products, including foundation, blush, and mascara, had higher urinary concentrations of MEP, mono-n-butyl phthalate (MBP), MP, and PP. Use of Colgate Total toothpaste was associated with 86.7% higher urinary triclosan concentrations. Use of sunscreen was associated with 57.8% higher urinary concentrations of BP-3. Our findings suggest that personal care product use is associated with higher exposure to certain phthalates, parabens, and other phenols in urine. This may be especially relevant in adolescent girls who have high use of personal care products during a period of important reproductive development.

Elevated concentrations of urinary triclocarban, phenol and paraben among pregnant women in Northern Puerto Rico: Predictors and trends

BACKGROUND

Understanding important sources and pathways of exposure to common chemicals known or suspected to impact human health is critical to eliminate or reduce the exposure. This is particularly important in areas such as Puerto Rico, where residents have higher exposures to numerous chemicals, as well as higher rates of many adverse health outcomes, compared to the mainland US.

OBJECTIVE

The aim of this study was to assess distributions, time trends, and predictors of urinary triclocarban, phenol, and paraben biomarkers measured at multiple times during pregnancy among women living in Northern Puerto Rico.

METHODS

We recruited 1003 pregnant women between years 2010 and 2016 from prenatal clinics and collected urine samples and questionnaire data on personal care product use at up to three separate visits, between 16 and 28 weeks gestation. Urine samples were analyzed for triclocarban, seven phenols and four parabens: 2,4-dichlorophenol, 2,5-dichlorophenol, benzophenone-3, bisphenol A (BPA), bisphenol S (BPS), bisphenol F, triclosan, butylparaben, ethylparaben, methylparaben, and propylparaben.

RESULTS

Detectable triclocarban, phenol and paraben concentrations among pregnant women were prevalent and tended to be higher than levels measured in women of reproductive age from the general US population, especially triclocarban, which had a median concentration 37 times higher in Puerto Rico participants (2.6 vs 0.07 ng/mL). A decreasing temporal trend was statistically significant for urine concentrations of BPA during the study period, while the BPA substitute BPS showed an increasing temporal trend. Significant and positive associations were found between biomarker concentrations with the products use in the past 48-h (soap, sunscreen, lotion, cosmetics). There was an increasing trend of triclocarban/triclosan urinary concentrations with increased concentrations of triclocarban/triclosan listed as the active ingredient in the bar soap/liquid soap products reported being used.

CONCLUSION

Our results suggest several potential exposure sources to triclocarban, phenols, and parabens in this population and may help inform targeted approaches to reduce exposure.

Effect of a Toothpaste/Mouthwash Containing Carica papaya Leaf Extract on Interdental Gingival Bleeding: A Randomized Controlled Trial

Clinical research on herbal-based dentifrice +/− mouth rinse products is very limited compared with the plethora of research on conventional oral care products under normal oral hygiene conditions. The aim of this study was to determine the anti-inflammatory effects of a novel plant Carica papaya leaf extract (CPLE) on interdental bleeding in healthy subjects. In this randomized, single-blind parallel-design study, the eligible subjects were generally healthy non-smokers, aged 18–26, who exhibited healthy periodontal conditions upon study entry. The participants were equally randomized into the following four groups: CPLE dentifrice, CPLE dentifrice and mouthwash, sodium lauryl sulfate (SLS)-free enzyme-containing dentifrice and SLS-free enzyme-containing dentifrice with essential oil (EO) mouthwash. Subjects were instructed to brush their teeth twice a day without changing their other brushing habits. Interdental bleeding (BOIP) was measured from inclusion (T₀) until the fourth week (T₄) of the study. Clinical efficacy was assessed after one, two, three and four weeks of home use. The analyses compared BOIP between groups and were then restricted to participants with ≥70% and then ≥80% bleeding sites at T₀. Pairwise comparisons between groups were performed at T₀ and T₄, and a logistic regression identified correlates of gingival bleeding (T₄). Among 100 subjects (2273 interdental sites), the median percentage of bleeding sites per participant at T₀ was 65%. The bleeding sites dramatically decreased in all groups between T₀ and T₄ (relative variations from −54% to −75%, p < 0.01 for all). Gingival bleeding did not significantly differ between the CPLE dentifrice and the SLS-free dentifrice +/− EO mouthwash groups (from p = 0.05 to p = 0.86), regardless of the baseline risk level. Among the CPLE dentifrice users, fewer bleeding sites were observed when toothpaste and mouthwash were combined compared to bleeding sites in those who used toothpaste alone (21% vs. 32%, p = 0.04). CPLE dentifrice/mouthwash provides an efficacious and natural alternative to SLS-free dentifrice +/−EO-containing mouthwash when used as an adjunct to mechanical oral care to reduce interdental gingival inflammation.

The role of endocrine disruptors in ocular surface diseases

Endocrine disruptors are a group of compounds that occur in increasing amounts in the environment. These compounds change the hormone homeostasis of the target organs regulated by those hormones, mostly by binding to their receptors and affecting their signaling pathways. Among the hormones altered by endocrine disruptors are sex hormones, thyroid hormones, and insulin. Studies have documented abnormalities in the reproductive and metabolic systems of various animal species exposed to endocrine disruptors. Endocrine disruptors can play a significant role in ocular diseases once hormone deficiency or excess are involved in the mechanism of that disease. Cataracts, dry eye disease and retinal diseases, such as macular hole and diabetic retinopathy, are some of the frequent problems where hormones have been implicated. We found that some compounds function as endocrine disruptors in the metabolism of body organs and systems. The increasing frequency of dry eye and other ocular diseases indicates the need to better investigate the potential relationships beyond the isolated associations mentioned by patients and documented as rare case reports. The evidence from case-control studies and experimental assays can provide the information necessary to confirm the endocrine effects of these chemicals in the pathophysiology of dry eye disease. We hypothesize that endocrine disruptors may contribute to the increase of ocular diseases, such as dry eye disease, in recent years.

Phthalate Metabolites in Maternal and Cord Plasma and Their Relations to Other Selected Endocrine Disruptors and Steroids

Endocrine disruptors (EDs) are known to have harmful effects on the human endocrine system; special effort is actually given to the exposure during pregnancy. Humans are usually exposed to a mixture of EDs, which may potentiate or antagonize each other, and the combined effect may be difficult to estimate. The main phthalate monoesters monoethyl-, mono-n-butyl-, monoisobutyl-, monobenzyl-, mono-(2-ethylhexyl)-, mono-(2-ethyl-5-hydroxyhexyl)- and mono-(2-ethyl-5-oxohexyl) phthalate were determined in 18 maternal (37th week of pregnancy) and cord plasma samples using liquid chromatography-tandem mass spectrometry. Previously determined levels of selected bisphenols, parabens and steroids were also considered in this study. In cord blood, there were significantly higher mono-n-butyl phthalate levels than in maternal blood (p=0.043). The results of multiple regression models showed that maternal plasma phthalates were negatively associated with cord plasma androstenedione, testosterone and dehydroepiandrosterone and positively associated with estradiol and estriol. For estriol, a cumulative association was also observed for Σbisphenols. To the best of our knowledge, this is the first pilot study evaluating the effect of prenatal exposure by multiple EDs on newborn steroidogenesis. Our results confirmed phthalate accumulation in the fetal area and disruption of fetal steroidogenesis. This preliminary study highlights the negative impacts of in utero EDs exposure on fetal steroidogenesis.

Biodegradation of four selected parabens with aerobic activated sludge and their transesterification product

Parabens are preservatives widely used in foodstuffs, cosmetics and pharmaceuticals, which have led to elevated paraben concentrations in wastewater and receiving waters. Laboratory-scale batch experiments were conducted to investigate the adsorption and degradation of parabens in an aerobic activated sludge system. Results show that biodegradation plays a key role in removing parabens from the aerobic system of wastewater treatment plants, while adsorption on the sludge is not significant. The effects of parent paraben concentration, concentration of mixed liquor suspended solids (MLSS), initial pH and temperature on degradation were investigated using kinetic models. The data shows that the degradation of parabens could be described by the first-order kinetic model with the rate constant ranging from 0.10 to 0.88 h^-1 at 25 °C and pH 7.0. Paraben degradation can be enhanced by increasing the MLSS concentration and temperature, or by decreasing the parent paraben concentration. Furthermore, the pH of the incubation system should be lower than 8.0. The half-lives of the parabens were estimated to range between 0.79 and 6.9 h, with methylparaben exhibiting the slowest degradation rate. During degradation in the present system, transesterification occurred, with methylparaben being the major transformation product in the incubation systems of ethylparaben, propylparaben and butylparaben. These results were confirmed by mass spectrometry and aliphatic alcohol additive experiments. This is the first discovery of paraben transesterification in an activated sludge system, and it is associated with trace methanol in the system.

In vitro genotoxic and cytotoxic effects of some paraben esters on human peripheral lymphocytes

Parabens (PBs) are p-hydroxybenzoic acid ester compounds commonly employed as antimicrobial preservatives, mainly in food, cosmetic, and pharmaceutical products. The aim of the present study was to investigate the genotoxic and cytotoxic effects of some paraben esters (butyl paraben, propyl paraben, isobutyl paraben, and isopropyl paraben) on human peripheral lymphocytes, using in vitro sister chromatid exchange (SCE), chromosome aberration (CA), and cytokinesis-block micronucleus (CBMN) tests. Lymphocyte cultures were treated with four concentrations of PBs (100, 50, 25 and 10 µg/mL) for 24 and 48 h. Paraben esters significantly induced MN formations as compared to solvent control. Furthermore, butyl paraben and propyl paraben increased MN formations a concentration-dependent manner at 24 and 48 h. PBs increased the CA at 24 and 48 h. However, this increase was not meaningful for butyl paraben and isopropyl paraben at 48 h when compared with solvent control. Butyl, isobutyl, and isopropyl paraben significantly increased the SCE at 24 and 48 h. However, propyl paraben did not induce SCE meaningfully in both treatment periods. A significant decrease in the cytokinesis-block proliferation index and mitotic index was observed in cells exposed to all concentrations of PBs at 24 and 48 h. However, proliferation index was not affected at all concentrations of PBs after 24 h treatment, although it was decreased at the highest concentration of PBs at 48 h. It is concluded that all of the paraben esters used in this study have highly genotoxic and cytotoxic effects on human lymphocytes cells in vitro.

Validation of Arxula Yeast Estrogen Screen assay for detection of estrogenic activity in water samples: Results of an international interlaboratory study

Endocrine-active substances can adversely impact the aquatic ecosystems. A special emphasis is laid, among others, on the effects of estrogens and estrogen mimicking compounds. Effect-based screening methods like in vitro bioassays are suitable tools to detect and quantify endocrine activities of known and unknown mixtures. This study describes the validation of the Arxula-Yeast Estrogen Screen (A-YES®) assay, an effect-based method for the detection of the estrogenic potential of water and waste water. This reporter gene assay, provided in ready to use format, is based on the activation of the human estrogen receptor alpha. The user-friendly A-YES® enables inexperienced operators to rapidly become competent with the assay. Fourteen laboratories from four countries with different training levels analyzed 17β-estradiol equivalent concentrations (EEQ) in spiked and unspiked waste water effluent and surface water samples, in waste water influent and spiked salt water samples and in a mixture of three bisphenols. The limit of detection (LOD) for untreated samples was 1.8ng/L 17β-estradiol (E2). Relative repeatability and reproducibility standard deviation for samples with EEQ above the LOD (mean EEQ values between 6.3 and 20.4ng/L) ranged from 7.5 to 21.4% and 16.6 to 28.0%, respectively. Precision results are comparable to other frequently used analytical methods for estrogens. The A-YES® has been demonstrated to be an accurate, precise and robust bioassay. The results have been included in the ISO draft standard. The assay was shown to be applicable for testing of typical waste water influent, effluent and saline water. Other studies have shown that the assay can be used with enriched samples, which lower the LOD to the pg/L range. The validation of the A-YES® and the development of a corresponding international standard constitute a step further towards harmonized and reliable bioassays for the effect-based analysis of estrogens and estrogen-like compounds in water samples.

Risks and benefits related to alimentary exposure to xenoestrogens

Xenoestrogens are widely diffused in the environment and in food, thus a large portion of human population worldwide is exposed to them. Among alimentary xenoestrogens, phytoestrogens (PhyEs) are increasingly being consumed because of their potential health benefits, although there are also important risks associated to their ingestion. Furthermore, other xenoestrogens that may be present in food are represented by other chemicals possessing estrogenic activities, that are commonly defined as endocrine disrupting chemicals (EDCs). EDCs pose a serious health concern since they may cause a wide range of health problems, starting from pre-birth till adult lifelong exposure. We herein provide an overview of the main classes of xenoestrogens, which are classified on the basis of their origin, their structures and their occurrence in the food chain. Furthermore, their either beneficial or toxic effects on human health are discussed in this review.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.