Associations between exposure to a mixture of phenols, parabens, and phthalates and sex steroid hormones in children 6-19 years from NHANES, 2013-2016

Urinary phthalate/DINCH metabolites associations with kisspeptin and reproductive hormones in teenagers: A cross-sectional study from the HBM4EU aligned studies

BACKGROUND

Exposure to phthalate/DINCH metabolites can induce human reproductive toxicity, however, their endocrine-disrupting mechanisms are not fully elucidated.

OBJECTIVE

To investigate the association between concentrations of phthalate/DINCH metabolites, serum kisspeptin, and reproductive hormones among European teenagers from three of the HBM4EU Aligned Studies.

METHODS

In 733 Belgian (FLEHS IV study), Slovak (PCB cohort follow-up), and Spanish (BEA study) teenagers, ten phthalate and two DINCH metabolites were measured in urine by high-performance liquid chromatography-tandem mass spectrometry. Serum kisspeptin (kiss54) protein, follicle-stimulating hormone (FSH), total testosterone (TT), estradiol (E2), and sex hormone-binding globulin (SHBG) levels were measured by immunosorbent assays. Free Androgen Index (FAI) was calculated as a proxy of free testosterone. Adjusted sex-stratified linear regression models for individual studies, mixed effect models (LME) accounting for random effects for pooled studies, and g-computation and Bayesian kernel machine regression (BKMR) models for the phthalate/DINCH mixture were performed.

RESULTS

The LME suggested that each IQR increase in ln-transformed levels of several phthalates was associated with lower kisspeptin [MnBP: %change (95%CI): -2.8 (-4.2;-0.4); MEHP: -1.4 (-3.4,0.2)] and higher FSH [∑DINP: 11.8 (-0.6;25.1)] levels in females from pooled studies. G-computation showed that the phthalates/DINCH mixture was associated with lower kisspeptin [-4.28 (-8.07;-0.34)] and higher FSH [22.13 (0.5;48.4)] also in females; BKMR showed similar although non-significant pattern. In males, higher phthalates metabolites [MEHP: -12.22 (-21.09;-1.18); oxo-MEHP: -12.73 (-22.34;-1.93)] were associated with lower TT and FAI, although higher DINCH [OH-MINCH: 16.31 (6.23;27.35), cx-MINCH: 16.80 (7.03;27.46), ∑DINCH: 17.37 (7.26;29.74)] were associated with higher TT levels. No mixture associations were found in males.

CONCLUSION

We observed sex-specific associations between urinary concentrations of phthalate/DINCH metabolites and the panel of selected effect biomarkers (kisspeptin and reproductive hormones). This suggests that exposure to phthalates would be associated with changes in kisspeptin levels, which would affect the HPG axis and thus influence reproductive health. However, further research is needed, particularly for phthalate replacements such as DINCH.

Early childhood exposures to phthalates in association with attention-deficit/hyperactivity disorder behaviors in middle childhood and adolescence in the ReCHARGE study

BACKGROUND

Early-life exposure to phthalates alters behaviors in animals. However, epidemiological evidence on childhood phthalate exposure and attention-deficit/hyperactivity disorder (ADHD) behaviors is limited.

METHODS

This study included 243 children from the ReCHARGE (Revisiting Childhood Autism Risks from Genetics and Environment) study, who were previously classified as having autism spectrum disorder (ASD), developmental delay, other early concerns, and typical development in the CHARGE case-control study. Twenty phthalate metabolites were measured in spot urine samples collected from children aged 2-5 years. Parents reported on children's ADHD symptoms at ages 8-18 years using Conners-3 Parent Rating Scale. Covariate-adjusted negative binomial generalized linear models were used to investigate associations between individual phthalate metabolite concentrations and raw scores. Weighted quantile sum (WQS) regression with repeated holdout validation was used to examine mixture effects of phthalate metabolites on behavioral scores. Effect modification by child sex was evaluated.

RESULTS

Among 12 phthalate metabolites detected in >75% of the samples, higher mono-2-heptyl phthalate (MHPP) was associated with higher scores on Inattentive (β per doubling = 0.05, 95% confidence interval [CI]: 0.02, 0.08) and Hyperactive/Impulsive scales (β = 0.04, 95% CI: 0.00, 0.07), especially among children with ASD. Higher mono-carboxy isooctyl phthalate (MCiOP) was associated with higher Hyperactivity/Impulsivity scores (β = 0.07, 95% CI: -0.01, 0.15), especially among typically developing children. The associations of the molar sum of high molecular weight (HMW) phthalate metabolites and a phthalate metabolite mixture with Hyperactivity/Impulsivity scores were modified by sex, showing more pronounced adverse associations among females.

CONCLUSION

Exposure to phthalates during early childhood may impact ADHD behaviors in middle childhood and adolescence, particularly among females. Although our findings may not be broadly generalizable due to the diverse diagnostic profiles within our study population, our robust findings on sex-specific associations warrant further investigations.

Prenatal exposure to a mixture of organophosphate flame retardants and infant neurodevelopment: A prospective cohort study in Shandong, China

BACKGROUND

Previous studies have suggested that prenatal exposure to organophosphate flame retardants (OPFRs) may have adverse effect on early neurodevelopment, but limited data are available in China, and the overall effects of OPFRs mixture are still unclear.

OBJECTIVE

This study aimed to investigate the association between prenatal exposure to OPFR metabolites mixture and the neurodevelopment of 1-year-old infants.

METHODS

A total of 270 mother-infant pairs were recruited from the Laizhou Wan (Bay) Birth Cohort in China. Ten OPFR metabolites were measured in maternal urine. Neurodevelopment of 1-year-old infants was assessed using the Gesell Developmental Schedules (GDS) and presented by the developmental quotient (DQ) score. Multivariate linear regression and weighted quantile sum (WQS) regression models were conducted to estimate the association of prenatal exposure to seven individual OPFR metabolites and their mixture with infant neurodevelopment.

RESULTS

The positive rates of seven OPFR metabolites in the urine of pregnant women were greater than 70% with the median concentration ranged within 0.13-3.53 μg/g creatinine. The multivariate linear regression model showed significant negative associations between bis (1-chloro-2-propyl) phosphate (BCIPP), din-butyl phosphate (DnBP), and total OPFR metabolites exposure and neurodevelopment in all infants. Results from the WQS model consistently revealed that the OPFR metabolites mixture was inversely associated with infant neurodevelopment. Each quartile increased in the seven OPFR metabolites mixture was associated with a 1.59 decrease (95% CI: 2.96, -0.21) in gross motor DQ scores, a 1.41 decrease (95% CI: 2.38, -0.43) in adaptive DQ scores, and a 1.08 decrease (95% CI: 2.15, -0.02) in social DQ scores, among which BCIPP, bis (1, 3-dichloro-2-propyl) phosphate (BDCIPP) and DnBP were the main contributors.

CONCLUSION

Prenatal exposure to a mixture of OPFRs was negatively associated with early infant neurodevelopment, particularly in gross motor, adaptive, and social domains.

Vitamin D Deficiency Exacerbates Poor Sleep Outcomes with Endocrine-Disrupting Chemicals Exposure: A Large American Population Study

Phthalates and bisphenol A are recognized as the predominant endocrine-disrupting substances (EDCs) in the environment, but their impact on sleep health remains unclear. Vitamin D has often been reported to play a role in sleep health and may be affected by endocrine-disrupting compounds. The study utilized data from 5476 individuals in the NHANES project to investigate the correlation between combined exposure to environmental EDCs and sleep duration through modeling various exposures. Furthermore, it emphasizes the importance of vitamin D in the present scenario. Preliminary analyses suggested that vitamin D-deficient individuals generally slept shorter than individuals with normal vitamin D (p < 0.05). Exposure to Mono-ethyl phthalate (MEP), triclosan (TRS), and Mono-benzyl phthalate (MZP), either alone or in combination, was associated with reduced sleep duration and a greater risk of vitamin D deficiency. Individuals with low vitamin D levels exposed to TRS experienced shorter sleep duration than those with normal vitamin D levels (p < 0.05). TRS and MZP were identified as crucial factors in patient outcomes when evaluating mixed exposures (p < 0.05). The results provide new data supporting a link between exposure to EDCs and insufficient sleep length. Additionally, they imply that a vitamin D shortage may worsen the sleep problems induced by EDCs.

The association between PM2.5 components and blood pressure changes in late pregnancy: A combined analysis of traditional and machine learning models

BACKGROUND

PM2.5 is a harmful mixture of various chemical components that pose a challenge in determining their individual and combined health effects due to multicollinearity issues with traditional linear regression models. This study aimed to develop an analytical methodology combining traditional and novel machine learning models to evaluate PM2.5's combined effects on blood pressure (BP) and identify the most toxic components.

METHODS

We measured late-pregnancy BP of 1138 women from the Heshan cohort while simultaneously analyzing 31 PM2.5 components. We utilized multiple linear regression modeling to establish the relationship between PM2.5 components and late-pregnancy BP and applied Random Forest (RF) and generalized Weighted Quantile Sum (gWQS) regression to identify the most toxic components contributing to elevated BP and to quantitatively evaluate the cumulative effect of the PM2.5 component mixtures.

RESULTS

The results revealed that 16 PM2.5 components, such as EC, OC, Ti, Fe, Mn, Cu, Cd, Mg, K, Pb, Se, Na+, K+, Cl-, NO3-, and F-, contributed to elevated systolic blood pressure (SBP), while 26 components, including two carbon components (EC, OC), fourteen metallics (Ti, Fe, Mn, Cr, Mo, Co, Cu, Zn, Cd, Na, Mg, Al, K, Pb), one metalloid (Se), and nine water-soluble ions (Na+, K+, Mg2+, Ca2+, NH4+, Cl-, NO3-, SO42-, F-), contributed to elevated diastolic blood pressure (DBP). Mn and Cr were the most toxic components for elevated SBP and DBP, respectively, as analyzed by RF and gWQS models and verified against each other. Exposure to PM2.5 component mixtures increased SBP by 1.04 mmHg (95% CI: 0.33-1.76) and DBP by 1.13 mmHg (95% CI: 0.47-1.78).

CONCLUSIONS

Our study highlights the effectiveness of combining traditional and novel models as an analytical strategy to quantify the health effects of PM2.5 constituent mixtures.

Environmental exposure to per- and polyfluoroalkyl substances mixture and asthma in adolescents

BACKGROUND

Previous epidemiological studies about the relationship between per- and polyfluoroalkyl substances (PFAS) concentrations and adolescent asthma have typically examined single PFAS, without considering the mixtures effects of PFAS.

METHODS

Using data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES), 886 adolescents aged 12-19 years were included in this study. We explored the association between PFAS mixture concentrations and adolescent asthma using weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models, respectively.

RESULTS

After adjusting for confounders, the results of the WQS regression and BKMR models were consistent, with mixed exposure to the five PFAS not significantly associated with asthma in all adolescents. The association remained nonsignificant in the subgroup analysis by sex.

CONCLUSIONS

Our study demonstrated no significant association between mixed exposure to PFAS and adolescent asthma, and more large cohort studies are needed to confirm this in the future.

Phthalate metabolites and sex steroid hormones in relation to obesity in US adults: NHANES 2013-2016

Background

Obesity and metabolic syndrome pose significant health challenges in the United States (US), with connections to disruptions in sex hormone regulation. The increasing prevalence of obesity and metabolic syndrome might be associated with exposure to phthalates (PAEs). Further exploration of the impact of PAEs on obesity is crucial, particularly from a sex hormone perspective.

Methods

A total of 7780 adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016 were included in the study. Principal component analysis (PCA) coupled with multinomial logistic regression was employed to elucidate the association between urinary PAEs metabolite concentrations and the likelihood of obesity. Weighted quartiles sum (WQS) regression was utilized to consolidate the impact of mixed PAEs exposure on sex hormone levels (total testosterone (TT), estradiol and sex hormone-binding globulin (SHBG)). We also delved into machine learning models to accurately discern obesity status and identify the key variables contributing most to these models.

Results

Principal Component 1 (PC1), characterized by mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) as major contributors, exhibited a negative association with obesity. Conversely, PC2, with monocarboxyononyl phthalate (MCNP), monocarboxyoctyl phthalate (MCOP), and mono(3-carboxypropyl) phthalate (MCPP) as major contributors, showed a positive association with obesity. Mixed exposure to PAEs was associated with decreased TT levels and increased estradiol and SHBG. During the exploration of the interrelations among obesity, sex hormones, and PAEs, models based on Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) algorithms demonstrated the best classification efficacy. In both models, sex hormones exhibited the highest variable importance, and certain phthalate metabolites made significant contributions to the model's performance.

Conclusions

Individuals with obesity exhibit lower levels of TT and SHBG, accompanied by elevated estradiol levels. Exposure to PAEs disrupts sex hormone levels, contributing to an increased risk of obesity in US adults. In the exploration of the interrelationships among these three factors, the RF and XGBoost algorithm models demonstrated superior performance, with sex hormones displaying higher variable importance.

Exposure to endocrine disrupting chemicals from beverage packaging materials and risk assessment for consumers

This study investigated the influence of beverage packaging materials on the presence of endocrine disrupting chemicals (EDCs) in plastic, glass, carton, aluminium, and tin canned non-alcoholic beverages. Results showed that 63 EDCs including perfluoroalkyl and polyfluoroalkyl substances (PFAS), bisphenols, parabens, benzophenone-type UV-filters, biocides, nitrophenols, and alkylphenols, were detected in 144/162 screened products. Detected ∑63EDC concentrations ranged from 1.3 to 19,600 ng/L. EDC concentrations were higher in beverages packaged in metal cans while lower or no levels were detected in glass, plastic, and carton packaged drinks. Bisphenol levels were higher on average in canned beverages compared to glass (p < 0.01) and plastic products (p < 0.05) produced by the same brand and manufacturer. Two structural isomers of bisphenol A (BPA) were identified in 19 beverages, constituting the first detection in foodstuffs. The calculated daily intake of detected EDCs showed that exposure to BPA from per capita beverage consumption of 364 mL/day are up to 2000-fold higher than the newly revised safety guideline for BPA recommended by the EFSA (European Food Safety Authority). Overall, these findings suggest that BPA exposure poses a potential health hazard for individuals who regularly consume non-alcoholic beverages packaged in aluminium or tin cans, particularly young children.

The Association Between SHBG and Osteoporosis: A NHANES Cross-Sectional Study and A Bidirectional Mendelian Randomization

This study aimed to examine the association between sex hormone-binding globulin (SHBG) and osteoporosis through a cross-sectional study and a two-sample bidirectional Mendelian randomization (MR). We used the National Health and Nutrition Examination Survey (NHANES) 2013-2014 and 2015-2016 data, with exposure as serum SHBG and outcome as osteoporosis and performed multivariate logistic regression to test the correlation between SHBG and osteoporosis. To determine the causal relationship between SHBG and osteoporosis, a two-sample bidirectional MR was employed. The genome-wide association study (GWAS) dataset for SHBG (n = 189,473) was obtained from the IEU database, and the GWAS dataset for osteoporosis (n = 212,778) was obtained from the FinnGen bioBank. The principal MR technique was inverse-variance weighting (IVW). In MR analyses, the MR-Egger intercept and Cochran Q test were used to detect multiple validity and horizontal heterogeneity. 1249 older adult participants (age ≥ 60) were involved in the cross-sectional study, including 113 osteoporosis cases. We identified a significant relationship between circulating SHBG concentration and osteoporosis risk [OR 3.963, 95% CI (2.095-7.495), P < 0.05]. Subgroup analysis indicated that SHBG was closely linked to the risk of osteoporosis in the female population [OR 1.008, 95% CI (1.002-1.013), P = 0.005] but not in males (P = 0.065). In addition, The IVW approach suggested a causal connection between SHBG and increased osteoporosis risk [OR 1.479, 95% CI (1.144-1.912), P = 0.003], and the MR-Egger intercept and the Cochran Q test validated the consistency of the MR results. Finally, the reverse MR analysis declined to identify a causal relation between SHBG and osteoporosis. Our research demonstrates a significant causal connection between circulating SHBG levels and increased osteoporosis risk. These results indicate that high SHBG may be associated with the risk of osteoporosis in postmenopausal women, but more research is needed.

Multi-omic analysis of precocious puberty girls: pathway changes and metabolite validation

Objective

Precocious puberty (PP) is a prevalent endocrine disorder affecting the physical and mental wellbeing of children. Identifying the triggering factors of PP has become a central issue. This study seeks to investigate the metabolomic and transcriptomic alterations in PP.

Material and methods

First, 37 school-aged girls diagnosed with PP and 25 age-matched prepubertal control girls were recruited, and the fecal samples were collected for non-targeted metabolomic analysis to screen for differentially expressed metabolites (DEMs). Subsequently, an animal model of PP was constructed by danazol administration to neonatal female rats, and both fecal non-targeted metabolomics and serum next-generation transcriptomic sequencing were performed to screen DEMs and differentially expressed genes (DEGs) in PP. Moreover, the DEM co-existing in clinical and animal models was administrated to PP rats to explore the role of the target metabolite in PP.

Results

A total of 24 DEMs in PP clinical samples and 180 DEMs and 425 DEGs in PP animal samples were identified. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these DEMs and DEGs were enriched in disease-associated pathways, including fatty acid synthesis, glycerolipid metabolism, pyrimidine metabolism, steroid hormone biosynthesis, progesterone-mediated oocyte maturation, and gonadotropin-releasing hormone (GnRH) signaling pathway, forming a tight DEM-DEG pathway regulatory network. Further DEM validation demonstrated that thymine supplementation delayed the opening of the vagina and development of PP in model rats.

Conclusion

This study reveals that the metabolomic and transcriptomic changes, along with enriched pathways, are implicated in PP based on clinical and animal analyses. The findings may provide new strategies and research avenues for PP treatment.

Associations of exposure to metals with total and allergen-specific IgE: An NHANES analysis (2005-2006)

BACKGROUND

Immunoglobulin E (IgE) is a diagnostic biomarker for allergic diseases. While some metal exposure has been found to be associated with allergic diseases, there are still a lot of knowledge gaps regarding the relationship between metal exposure and allergen-specific IgE antibodies, particularly in adults.

METHODS

We included a total of 1433 adult participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES), all of whom had concentrations of 10 metals (including Barium (Ba), Cadmium (Cd), Cobalt (Co), Cesium (Cs), Molybdenum (Mo), Lead (Pb), Antimony (Sb), Thallium (Tl), Tungsten (Tu), and Uranium (Ur)) in urine, as well as measurements of 19 allergen-specific IgE and total IgE antibodies. Linear regression, logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to estimate associations between metals and total and allergen-specific IgE.

RESULTS

Linear regression models revealed a positive correlation between Pb and Cd levels and the total IgE levels. Furthermore, the WQS and BKMR models suggested a positive association between mixed metals and total IgE levels, with the WQS model highlighting Pb and Cd as the major contributors. Logistic regression models showed positive correlations between Pb and food sensitization, Ur and plant sensitization, negative correlations between Cs and plant sensitization, Co and dust mite and pet sensitization, Mo and dust mite and cockroach sensitization, and Tl and mold sensitization. Moreover, the BKMR results indicated a statistically significant negative correlation between mixed metals and mold sensitization.

CONCLUSION

According to the research findings, exposure to metals is associated with total and allergen-specific IgE in American adults. Further assessment of these relationships is necessary in representative populations of other countries.

Effect of zinc intake on association between fluoride exposure and abnormal sex steroid hormones among US pubertal males: NHANES, 2013-2016

Excessive fluoride exposure can disturb the balance of sex hormones. Zinc is essential for sex hormone synthesis and spermatogenesis. But it is not clear how zinc affects the relationship of fluoride exposure with abnormal sex steroid hormones. Here, a total of 1008 pubertal males from the National Health and Nutrition Examination Survey (NHANES) in two cycles (2013-2014, 2015-2016) were enrolled. The concentrations of water fluoride and plasma fluoride and the levels of serum testosterone, estradiol, and sex hormone binding globulin (SHBG) were measured. Two 24-h dietary recall interviews were conducted to assess the dietary zinc intake. The relationships of fluoride exposure and zinc intake with sex hormones were examined using linear regression and logistic regression models, while the generalized additive model was used to evaluate their non-linear relationship. Our findings revealed that for every two-fold increase in plasma fluoride concentration, testosterone levels decreased by 7.27% (95% CI - 11.49%, - 2.86%) and estradiol levels decreased by 8.73% (95% CI - 13.61%, - 3.57%). There was also significant non-linear association observed between zinc intake and SHBG levels. Being in the first tertile of plasma fluoride had a 60% lower risk of high SHBG (OR = 0.40, 95% CI 0.18, 0.89) compared with being in the second tertile. When compared to the first tertile, being in the second tertile of zinc intake was associated with a 63% (OR = 0.37, 95% CI 0.14, 0.98) lower risk of high SHBG. Furthermore, we observed an interactive effect between the plasma fluoride and zinc intake on estradiol and SHBG, as well as the risk of high SHBG (P-interaction < 0.10). These findings suggest that fluoride exposure and zinc intake can affect sex steroid hormone levels and the risk of high SHBG. Notably, zinc intake may alleviate the increased risk of high SHBG and the abnormal changes of estradiol and SHBG caused by higher fluoride exposure.

Associations Between Phthalate, Eosinophil, and Aeroallergen Sensitization in Schoolchildren

BACKGROUND

Phthalates and bisphenol A (BPA) are endocrine-disrupting chemicals and may cause immunological disorders in children. Therefore, according to the region, we investigated urinary phthalates and BPA levels and the relationship between urinary phthalate, aeroallergen sensitization, and eosinophil count during the coronavirus disease 2019 pandemic.

METHODS

In total, 203 schoolchildren (134 residential and 69 industrial) aged 7-10 years were enrolled between July 2021 and July 2022. The BPA, metabolites of four high-molecular-weight phthalates (Σ4HMWP) and three low-molecular-weight phthalates (Σ3LMWP), were measured in the urine samples. Total eosinophil count and transepidermal water loss (TEWL) were also measured along with the skin prick test.

RESULTS

The two groups had no differences in terms of BPA. The industrial group had significantly more plastic container usage, and there was a difference in the Σ3LMWP (P < 0.001) between the two groups but no difference in the Σ4HMWP (P = 0.234). The quartiles of urinary Σ4HMWP and Σ3LMWP (P < were not associated with the total eosinophil count, vitamin D level, or TEWL. After adjusting for cofactors, the quartiles of urinary Σ4HMWP and Σ3LMWP were significantly associated with total eosinophil count (P < 0.001) but not with aeroallergen sensitization or vitamin D.

CONCLUSION

Exposure to phthalates was significantly associated with eosinophil count but not with aeroallergen sensitization or vitamin D. Therefore, reducing the use of plastic containers may effectively prevent exposure to phthalates and reduce Th2 cell-mediated inflammation in children.

Systematic evidence mapping informs a class-based approach to assessing personal care products and pubertal timing

BACKGROUND

Personal care products (PCPs) contain many different compounds and are a source of exposure to endocrine disrupting chemicals (EDCs), including phthalates and phenols. Early-life exposure to EDCs commonly found in PCPs has been linked to earlier onset of puberty.

OBJECTIVE

To characterize the human and animal evidence on the association between puberty-related outcomes and exposure to PCPs and their chemical constituents and, if there is sufficient evidence, identify groups of chemicals and outcomes to support a systematic review for a class-based hazard or risk assessment.

METHODS

We followed the OHAT systematic review framework to characterize the human and animal evidence on the association between puberty-related health outcomes and exposure to PCPs and their chemical constituents.

RESULTS

Ninety-eight human and 299 animal studies that evaluated a total of 96 different chemicals were identified and mapped by key concepts including chemical class, data stream, and puberty-related health outcome. Among these studies, phthalates and phenols were the most well-studied chemical classes. Most of the phthalate and phenol studies examined secondary sex characteristics and changes in estradiol and testosterone levels. Studies evaluating PCP use and other chemical classes (e.g., parabens) had less data.

CONCLUSIONS

This systematic evidence map identified and mapped the published research evaluating the association between exposure to PCPs and their chemical constituents and puberty-related health outcomes. The resulting interactive visualization allows researchers to make evidence-based decisions on the available research by enabling them to search, sort, and filter the literature base of puberty-related studies by key concepts. This map can be used by researchers and regulators to prioritize and target future research and funding to reduce uncertainties and address data gaps. It also provides information to inform a class-based hazard or risk assessment on the association between phthalate and phenol exposures and puberty-related health outcomes.

Associations between urinary heavy metals and anxiety among adults in the National Health and Nutrition Examination Survey (NHANES), 2007-2012

BACKGROUND

Few studies have investigated the associations between heavy metals and anxiety. The purpose of this study was to examine the associations between single and combined exposure to heavy metals and anxiety.

METHODS

This study employed data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2012. Anxiety was assessed by patients self-reporting the number of anxious days per month. First, we evaluated the associations between 10 heavy metals single exposure and anxiety by multivariable logistic regression. We then selected 5 heavy metals (cadmium, antimony, cobalt, tungsten, and uranium) for further analysis by elastic net regression. Subsequently, principal component analysis (PCA), weighted quantile regression (WQS), and Bayesian kernel machine regression (BKMR) were utilized to evaluate the associations between 5 heavy metals co-exposure and anxiety.

RESULTS

This study included 4512 participants, among whom 1206 participants were in an anxiety state. Urinary cadmium and antimony were separately related to an increased risk of anxiety (p for trend <0.01 and < 0.01, respectively). In PCA analysis, PC1 was associated with an increased risk of anxiety (p for trend <0.001). In WQS analysis, the positive WQS index was substantially linked with the risk of anxiety (OR (95%CI): 1.23 (1.04,1.39)). In BKMR analysis, the overall effects of co-exposure to heavy metals were positively connected with anxiety.

CONCLUSION

Our study identified a positive correlation between individual exposure to cadmium and antimony and the risk of anxiety. Additionally, the co-exposure to cadmium, antimony, cobalt, tungsten, and uranium was associated with an increased risk of anxiety.

Associations between exposure to phthalates and rheumatoid arthritis risk among adults in NHANES, 2007-2016

BACKGROUND

The etiology of rheumatoid arthritis (RA) is multifactorial, encompassing genetics and environment. Despite the widespread use of phthalates as chemical additives, their potential impact on RA has received limited investigation. This study aimed to evaluate the potential associations between exposure to phthalates and rheumatoid arthritis risk among adults.

METHODS

Participants ≥20 years were analyzed from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. Multivariable logistic regression was used to examine the association between exposure to phthalates and RA in two models. Additionally, subgroup analyses stratified by gender and age were also performed. The nonlinear relationship between RA and phthalates was characterized by smooth curve fittings and generalized additive models.

RESULTS

Ultimately, 9322 participants (RA: 601, without RA: 8632) were analyzed. The prevalence of RA increased with higher quantiles of MECPP (Q4, OR: 1.43, 95% CI: 1.07-1.91), MBP (Q2, OR: 1.30, 95% CI: 1.01-1.67), MEHHP (Q3, OR: 1.39, 95% CI: 1.07-1.81; Q4, OR: 1.35, 95% CI: 1.02-1.87) and MEOP (Q2, OR:1.35, 95% CI: 1.03-1.76) compared to the lowest quartile. A nonlinear relationship positive association was also observed between MECPP (P for non-linearity = 0.0074)) and MEHHP (P for non-linearity = 0.0046)) levels and RA. Subgroup analysis showed the association between phthalate levels and RA was mainly present in males or participants aged more than 60 years.

CONCLUSIONS

Our results demonstrated that exposure to phthalates is associated with an increased prevalence of RA among adults. Notably, such associations appear to be more pronounced in males and older people.

Co-exposure to parabens and triclosan and associations with cognitive impairment in an elderly population from Shenzhen, China

Parabens and triclosan (TCS) have been extensively applied in personal care products (PCPs) as preservatives and antibacterial agents. However, their potentiality to disrupt the neurological system has induced increasing concern. The elderly population is at a higher risk of neurodegenerative disorder, although research on its association with PCP exposure remains scarce. Here, we measured the urinary levels of four parabens, TCS, and an oxidative stress marker among 540 participants from the Shenzhen aging-related disorder cohort during 2017-2018. The Mini-Mental State Examination (MMSE) was used to assess the cognitive status of participants. Their demographic, dietary, and behavioral factors were collected via questionnaire survey. Among the four paraben analogs, the median concentration of methyl parabens (MeP) was the highest (Low-risk group: 1.21 ng/mL, High-risk group: 1.64 ng/mL). TCS and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were detected in more than 90% of the samples. Weighted quantile sum regression and quantile-based g-computation showed that the combined effect of all analytes was positively associated with the level of 8-OHdG. BtP, EtP and MeP were identified as the major contributors to the joint effect. After stratification by gender, females exhibited more pronounced changes in urinary 8-OHdG level than males. However, the positive correlation between co-exposure to parabens and TCS and cognitive impairment was not significant (p > 0.05) in both models, which warrants investigation with the larger sample size.

Individual and joint association of phenols, parabens, and phthalates with childhood lung function: Exploring the mediating role of peripheral immune responses

The functioning of the respiratory system can be interfered with by exposure to mixtures of environmental chemicals, however, the evidence is still ambiguous. We evaluated the association of exposure to mixtures of 14 chemicals, including 2 phenols, 2 parabens, and 10 phthalates, with four major lung function metrics. Based on data from the National Health and Nutrition Examination Survey 2007-2012, this analysis was conducted among 1462 children aged 6-19 years. Linear regression, Bayesian kernel machine regression, quantile-based g-computation regression, and a generalized additive model were performed to estimate the associations. Mediation analyses were performed to investigate plausible biological pathways mediated by immune cells. Our results indicated that the phenols, parabens, and phthalates mixture was negatively related to lung function parameters. And BPA and PP were identified as important contributors to negative associations with FEV₁, FVC, and PEF, with non-linear relationships observed between BPA and those outcomes. The most influential factor for a probable FEF_{25-75 %} decline was MCNP. BPA, and MCNP had an interaction effect on FEF_{25-75 %}. The association of PP with FVC and FEV₁ has been postulated to be mediated by neutrophils and monocytes. The findings offer insights into the associations of chemical mixtures with respiratory health and the possible driving mechanism, which would be of significance in adding novel evidence of the role of peripheral immune responses, as well as calling for remediation actions to be prioritized during childhood.

Parabens Promote Protumorigenic Effects in Luminal Breast Cancer Cell Lines With Diverse Genetic Ancestry

Context

One in 8 women will develop breast cancer in their lifetime. Yet, the burden of disease is greater in Black women. Black women have a 40% higher mortality rate than White women, and a higher incidence of breast cancer at age 40 and younger. While the underlying cause of this disparity is multifactorial, exposure to endocrine disrupting chemicals (EDCs) in hair and other personal care products has been associated with an increased risk of breast cancer. Parabens are known EDCs that are commonly used as preservatives in hair and other personal care products, and Black women are disproportionately exposed to products containing parabens.

Objective

Studies have shown that parabens impact breast cancer cell proliferation, death, migration/invasion, and metabolism, as well as gene expression in vitro. However, these studies were conducted using cell lines of European ancestry; to date, no studies have utilized breast cancer cell lines of West African ancestry to examine the effects of parabens on breast cancer progression. Like breast cancer cell lines with European ancestry, we hypothesize that parabens promote protumorigenic effects in breast cancer cell lines of West African ancestry.

Methods

Luminal breast cancer cell lines with West African ancestry (HCC1500) and European ancestry (MCF-7) were treated with biologically relevant doses of methylparaben, propylparaben, and butylparaben.

Results

Following treatment, estrogen receptor target gene expression and cell viability were examined. We observed altered estrogen receptor target gene expression and cell viability that was paraben and cell line specific.

Conclusion

This study provides greater insight into the tumorigenic role of parabens in the progression of breast cancer in Black women.

Persistent high exposure to exogenous phthalates and endogenous sex hormones associated with early pubertal onset among children: A 3.5-year longitudinal cohort study in China

BACKGROUND

Early onset of puberty could have significant impacts on childhood health, but the extent to which it was affected by phthalate esters (PAEs) and sex hormone disruption was not understood. The aim of this study is to investigate the associations between exposure to PAEs and sex hormone disruption and early onset of puberty in children.

METHODS

A longitudinal cohort study was conducted in China from May 2017 to Oct 2020, involving 740 children during consecutive visits. The onset of puberty was evaluated using Tanner definition, and early puberty was defined as an onset age less than the first 25 %, with cut-offs of 10.33 and 8.97 years for boys and girls, respectively. Serum testosterone (TT), estradiol (E₂) and urinary PAE metabolites were measured during three visits. Generalized linear models were used to explore the associations between PAE and sex hormones with the age of puberty onset, while log-binomial regressions were applied to assess the associations of persistent exposure to PAEs and sex hormones with early pubertal onset.

RESULTS

Approximately 86.0 % of boys and 90.2 % of girls completed puberty onset from pre-puberty, and more than 95 % of participants had PAE concentrations higher than the limit of detection. Boys showed higher exposure to PAE pollutants and higher TT levels. Persistent exposure to PAEs was positively associated with early pubertal onset in girls (ARR = 1.97, 95 %CI = 1.12, 3.46). Moreover, persistent exposure to PAEs and E₂ had synergistic associations with early pubertal onset in both boys (ARR = 4.77, 95 %CI = 1.06, 21.54) and girls (ARR = 7.07, 95 %CI = 1.51, 33.10). However, PAEs and TT had antagonistic associations only in boys (ARR = 0.44, 95 %CI = 0.07, 2.58).

CONCLUSION

Long-term exposure to PAEs might increase the risk of early pubertal onset, and it appears to work in synergy with E₂, while in antagonism with TT in boys' early pubertal onset. Reducing PAEs exposure might promote pubertal health.

Association of parabens and bisphenols with lung function in children aged 5-12 years from Shanghai, China

Epidemiological studies have reported potential effects of individual paraben or bisphenol exposure on lung function, but few studies have estimated their joint effects. We conducted a cross sectional survey to investigate the associations of parabens and bisphenols exposure with lung function in 205 children aged 5-12 years from Shanghai, China. Urinary concentrations of six parabens [methyl-, ethyl-, propyl-, butyl-, benzyl-, and heptyl-paraben (MeP, EtP, PrP, BuP, BzP, and HeP)] and seven bisphenols [bisphenol A (BPA), bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol B (BPB), bisphenol P (BPP), bisphenol S (BPS), and bisphenol Z (BPZ)] were assessed by the high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Lung function, including forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC, peak expiratory flow (PEF), and forced expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75%), was further measured. Linear regression, bayesian kernel machine regression (BKMR), and weighted quantile sum regression (WQS) evaluated the individual and joint relationships of the parabens and bisphenols with the lung function parameters. Further, the analysis was stratified by child sex. Parabens (MeP, EtP, PrP, and BuP) and bisphenols (BPA, BPAP, BPB, and BPS) with detection rates >75% were included for analyses. In linear regressions, parabens (MeP, PrP, and BuP) were generally negatively associated with FEV₁, FVC, PEF, and FEF_25-75%, but no associations for bisphenols were found. The association of parabens with lung function was more pronounced in girls. The aforementioned negative associations between parabens and lung function were confirmed by both the BKMR and WQS, with MeP being considered most heavily weighing chemical. Our findings suggested that exposure to parabens, either individuals or as a mixture, were associated with decreased lung function in children aged 5-12 years, and these associations were stronger among girls. Considering the cross-sectional study design, large longitudinal studies are warranted to confirm our findings.

Low-dose BPA and its substitute BPS promote ovarian cancer cell stemness via a non-canonical PINK1/p53 mitophagic signaling

The environmental toxicity of bisphenol A (BPA) and its analog like bisphenol S (BPS) have drawn wide attention, but their roles in cancer progression remain controversial. Here, we investigated the effect of BPA/BPS on the development of ovarian cancer. Human internal BPA/BPS exposure levels were analyzed from NHANES 2013-2016 data. We treated human ovarian cancer cells with 0-1000 nM BPA/BPS and found that 100 nM BPA/BPS treatment significantly increased Cancer Stem Cell (CSC) markers expression including OCT4, NANOG and SOX2. Cancer cell stemness evaluation induced by BPA/BPS was notably attenuated by the knockdown of PINK1 or Mdivi-1 treatment. The activation of PINK1 initiated mitophagy by inhibiting p-p53 nuclear translocation in a non-canonical manner. In vivo studies validated that BPA/BPS-exposed mice have higher tumor metastasis incidence compared with the control group, while mitophagy inhibition blocked such a promotion effect. In addition, CSC markers such as SOX2 had been found to be overexpressed in the tumor tissues of BPA/BPS exposure group. Taken together, the findings herein first provide the evidence that environmentally relevant BPA/BPS exposure could enhance ovarian cancer cell stemness through a non-canonical PINK1/p53 mitophagic pathway, raising concerns about the potential population hazards of BPA and other bisphenol analogs.

Urinary bisphenol A and S are associated with diminished ovarian reserve in women from an infertility clinic in Northern China

Bisphenol A (BPA) has been demonstrated to cause ovarian toxicity including disruption of steroidogenesis and inhibition of follicle growth. Still, human evidence is lacking on its analogs such as bisphenol F (BPF) and bisphenol S (BPS). In this study, we aimed to investigate the associations between exposure to BPA, BPF, and BPS with ovarian reserve in women of childbearing age. We recruited 111 women from an infertility clinic in Shenyang, North China between September 2020 and February 2021. Anti-müllerian hormone (AMH), follicle-stimulating hormone (FSH), and estradiol (E2) were measured as indicators of ovarian reserve. Urinary BPA, BPF, and BPS concentrations were quantified by ultra-high-performance liquid chromatography-triple quadruple mass spectrometry (UHPLC-MS/MS). Linear and logistic regression models were applied to assess the associations between urinary BPA, BPF, and BPS levels and indicators of ovarian reserve and DOR, respectively. Restricted cubic spline (RCS) models were further utilized to explore potential non-linear associations. Our results showed that urinary BPS concentrations were negatively associated with AMH (β = - 0.287, 95 %CI: - 0.505, - 0.070, P = 0.010) and this inverse relationship was further confirmed in the RCS model. In addition, higher levels of BPA and BPS exposure were associated with increased DOR risk (BPA: OR = 7.112, 95 %CI: 1.247, 40.588, P = 0.027; BPS: OR = 6.851, 95 %CI: 1.241, 37.818, P = 0.027). No significant associations of BPF exposure with ovarian reserve. Our findings implied that higher BPA and BPS exposure may be related to decreased ovarian reserve.

Studying paraben-induced estrogen receptor- and steroid hormone-related endocrine disruption effects via multi-level approaches

Increasing concerns have been raised on the health risks of parabens in the regard of their widespread applications and potential endocrine disrupting activities. In this study, four typical parabens, including methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), and butyl paraben (BuP) were systematically investigated for their estrogen receptor- and steroid hormone-related endocrine disruptions using multi-level approaches. Paraben exposure promoted the proliferation of MCF-7 cells, increased the luciferase activity in MVLN cells, and induced the vitellogenin (vtg) expression in zebrafish larvae, showing the typical estrogenic effects. The in vitro protein assays further revealed that PrP and BuP could bind with two isoforms of estrogen receptors (ERs). The estrogenic activities of parabens were predicted to be positively correlated with their chemical structure complexity by using molecular docking analysis. Furthermore, the synthesis and secretion of estradiol (E2) and testosterone (T) were significantly disturbed in H295R cells and zebrafish larvae, which could be regulated by paraben-induced transcriptional disturbance in both in vitro steroidogenesis and in vivo hypothalamic-pituitary-gonadal (HPG) axis. Parabens could disturb the endocrine system by activating the ERs and disrupting the steroid hormone synthesis and secretion, suggesting their potential deleterious risks to the environment and human health.

Associations between exposure to a mixture of phenols and sex steroid hormones among pre- and postmenopausal women: evidence from NHANES 2015-2016

Environmental phenols are well known as emerging endocrine-disrupting chemicals; however, their impacts on sex hormone homeostasis among pre- and postmenopausal women remain unknown. Our objective was to evaluate independent and combined relationships between phenol levels in urine and sex steroid hormones among 323 premenopausal women and 263 postmenopausal women from National Health and Nutrition Examination Survey (NHANES) 2015-2016. A total of 10 phenol concentrations in urine were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Serum concentrations of estradiol and total testosterone were measured by LC-MS/MS and serum sex hormone-binding globulin (SHBG) concentrations were measured using an immunofluorometric assay. Multivariable linear regression models were conducted to explore associations of individual phenol concentration in urine with natural logarithm-transformed serum hormone levels. Bayesian kernel machine regression (BKMR) model was conducted to evaluate phenol mixtures exposure in association with sex hormones among pre- and postmenopausal women, respectively. Considering both single-chemical models and multiple-chemical models, each doubling of urinary BPS concentration was significantly inversely related to serum SHBG concentration in premenopausal women (percent change: -6.70%, 95% confidence interval, CI: -11.12%, -2.73%; P = 0.002). Moreover, every doubling of urinary BP-3 concentration was significantly positively associated with SHBG level in serum (percent change: 3.53%, 95%CI: 0.70%, 5.70%; P = 0.008). Regarding postmenopausal women, inverse associations between urinary BPS levels and serum estradiol concentrations were observed (percent change: -8.62%, 95% CI: -15.33%, -2.06%; P = 0.012). The results revealed that BPS and BP-3 exposure may adversely disrupt sex hormone homeostasis at the current exposure levels among women in the USA. The findings and their underlying mechanisms are warranted to be confirmed and comprehensively interpreted in further epidemiological and experimental studies.

Association between polyfluoroalkyl substances exposure and sex steroids in adolescents: The mediating role of serum albumin

BACKGROUND

Polyfluoroalkyl substances (PFASs) are an emerging class of contaminants with endocrine disrupting hazards. The impact of PFASs exposure on sex steroids remain inconclusive.

METHODS

This study used data from the 2013-2016 National Health and Nutrition Examination Survey (NHANES), including 525 adolescents aged 12-19. We explored the association between serum PFASs and sex steroids using multiple linear regression, weighted quantified sum (WQS) regression, and Bayesian kernel machine regression (BKMR). Mediation analyses were performed to assess whether serum albumin mediates the effects of PFASs on sex steroids.

RESULTS

Single exposure to perfluorohexane sulfonic acid (PFHxS) or n-perfluorooctanoic acid (n-PFOA) was found to be inversely associated with sex hormone binding protein (SHBG) after adjustment for confounders. Results from both the WQS and BKMR models showed that mixed exposure to the five PFASs was negatively associated with SHBG and testosterone (TT) in all adolescents, while only in the WQS model, the mixed exposure to PFASs was negatively correlated with E₂ and FAI in boys and negatively correlated with TT and SHBG in girls. Serum albumin was found to possibly mediate 9.7 % of the association between mixed PFAS exposure and TT, and 9.7 % of the association between mixed PFAS exposure and SHBG.

CONCLUSION

Our study demonstrates a negative association between mixed exposure to PFASs and adolescent TT and SHBG levels, and suggests that albumin may merit further study as a potential target for PFAS harm reduction.

Independent and combined associations of urinary arsenic exposure and serum sex steroid hormones among 6-19-year old children and adolescents in NHANES 2013-2016

Arsenic exposure may disrupt sex steroid hormones, causing endocrine disruption. However, human evidence is limited and inconsistent, especially for children and adolescents. To evaluate the independent and combined associations between arsenic exposure and serum sex steroid hormones in children and adolescents, we conducted a cross-sectional analysis of data from 1063 participants aged 6 to 19 years from the 2013-2016 National Health and Nutrition Examination Survey (NHANES). Three urine arsenic metabolites were examined, as well as three serum sex steroid hormones, estradiol (E₂), total testosterone (TT), and sex hormone-binding globulin (SHBG). The ratio of TT to E₂ (TT/E₂) and the free androgen index (FAI) generated by TT/SHBG were also assessed. Linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to evaluate the associations of individual or arsenic metabolite combinations with sex steroid hormones by gender and age stratification. Positive associations were found between total arsenic and arsenic metabolites with TT, E₂, and FAI. In contrast, negative associations were found between arsenic metabolites and SHBG. Furthermore, there was an interaction after gender-age stratification between DMA and SHBG in female adolescents. Notably, based on the WQS and BKMR model results, the combined association of arsenic and its metabolites was positively associated with TT, E₂, and FAI and negatively associated with SHBG. Moreover, DMA and MMA dominated the highest weights among the arsenic metabolites. Overall, our results indicate that exposure to arsenic, either alone or in mixtures, may alter sex steroid hormone levels in children and adolescents.

Relationship between phthalates exposures and hyperuricemia in U.S. general population, a multi-cycle study of NHANES 2007-2016

BACKGROUND

Phthalates exposure might cause kidney damage and a potential risk for hyperuricemia. However, direct evidence on phthalates and hyperuricemia is somewhat limited.

OBJECTIVE

To examine associations between 10 phthalates metabolites and hyperuricemia in a large-scale representative of the U.S.

METHODS

A cross-sectional study of 6865 participants aged over 20 from NHANES 2007-2016 was performed. All participants had complete data on ten phthalate metabolites (MECPP, MnBP, MEHHP, MEOHP, MiBP, cx-MiNP, MCOP, MCPP, MEP, MBzP), hyperuricemia, and covariates. We used multivariable logistics regression, restricted cubic splines (RCS) model, and Bayesian kernel machine regression (BKMR) models to assess single, nonlinear, and mixed relationships between phthalate metabolites and hyperuricemia. As a complement, we also assessed the relationship between phthalate metabolites and serum uric acid (SUA) levels.

RESULTS

The multivariable logistics regression showed that MECPP, MEOHP, MEHHP, MBzP, and MiBP were generally positively associated with hyperuricemia (P_FDR < 0.05), especially in MiBP (Q3 (OR (95 %): 1.31 (1.02, 1.68)) and Q4 (OR (95 %): 1.68 (1.27, 2.24)), compared to Q1). All ten phthalate metabolites had a linear dose-response relationship with hyperuricemia in the RCS model (P for non-linear >0.05). BKMR showed that mixed phthalate metabolites were associated with a higher risk of hyperuricemia, with MBzP contributing the most (groupPIP = 0.999, condPIP = 1.000). We observed the consistent results between phthalate metabolites and SUA levels in three statistical models. The relationship between phthalate metabolites and hyperuricemia remained in the sensitivity analysis.

CONCLUSIONS

The present study suggests that exposure to phthalates, individually or jointly, might increase the risk of hyperuricemia. Since hyperuricemia influences on the quality of life, more explorations are needed to confirm these findings.

Association between exposure to phenols and parabens and cognitive function in older adults in the United States: A cross-sectional study

BACKGROUND

People are commonly exposed to mixtures of parabens and phenols. Most studies investigating such exposure and cognitive performance tend to assess only single chemicals, and the tools used to assess cognitive function are not uniform.

OBJECTIVE

This study aimed to examine the association between multiple parabens and phenols and cognitive function in older Americans.

METHODS

The study included data of older Americans from two cycles of the NHANES survey. Participants were divided into normal cognitive performance and low cognitive performance groups based on the scores of four cognitive tests: the Immediate Recall test (IRT), the Delayed Recall test (DRT), the Animal Fluency test (AFT) and the Digit Symbol Substitution test (DSST). Generalized linear regression models (GLMs), restricted cubic spline (RCS), weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) were used to assess relationships between chemical exposure and cognitive performance.

RESULTS

In this cross-sectional study, a total of 961 participants, 470 males and 491 females, were included. GLMs revealed positive association between high levels of bisphenol A (BPA) and low cognitive performance on DRT, especially in male (OR (95%CI): 2.25 (1.10-4.61)), and this association was consistent with WQS and BKMR. In female participants, the third quartile of BPA exposure showed a positive association with low cognition on IRT and global cognition. GLMs also showed that high levels of propylparaben were positively associated with cognitive performance on the IRT in male participants (OR (95%CI): 0.37 (0.18-0.76)). In BKMR, an overall positive correlation between the mixture and low cognition as measured with DRT was observed in male subjects when the mixture was at the 65th percentile or higher.

CONCLUSION

Exposure to a mixture of parabens and phenols was positively associated with low cognitive performance on DRT in older male subjects, while BPA was the main driver of this outcome.

Associations between urinary concentrations of bisphenols and serum concentrations of sex hormones among US. Males

BACKGROUND

Bisphenol A (BPA) exposure and its structural analogs (BPS and BPF) might cause endocrine alterations and adverse physiological effects. Few studies to date have directly explored the association between its structural analogs (BPS, BPF) and sex hormones in adult male participants. Therefore, we aimed to assess the associations between BPA, BPS, BPF, and sex hormones in American adult men.

METHODS

We used data from the U.S. National Health and Nutrition Examination Survey 2011-2016. We excluded participants without data available on sex hormones and urinary bisphenols. Furthermore, participants consuming sex hormone medications were excluded. Multivariable regression models were performed to assess the association between bisphenols and sex hormones.

RESULTS

In this study, 2367 participants were included. Of 2367, in 1575 participants, the data on BPS and BPF were available. We found that a per unit increase in BPF was associated with 0.575 ng/dL higher total testosterone (TT) (Model 2: 95% CI: 0.047, 1.103, P = 0.033). However, there was no significant association between BPA or BPS and TT. Furthermore, increased BPA and BPS levels were associated with higher levels of sex hormone-binding globulin (SHBG) (Model 2: β = 0.364, 95% CI: 0.158, 0.571; β = 0.25, 95% CI: 0.071, 0.429, respectively). Additionally, participants in the highest BPA exposure quartile (quartile 4) had 4.072 nmol/L higher levels of SHBG than those in quartile 1 (Model 2: 95% CI: 0.746, 7.397, P = 0.017; P for trend =0.005). Both BPA and BPS were negatively associated with free testosterone (FT, nmol/L) after full adjustment (Model 2, β = - 0.01%, P = 0.0211, P = 0.0211; Model 2, β = - 0.01%, P = 0.0258, respectively). However, BPF was positively associated with FT (Model 2, β = 0.0029%, P = 0.0028).

CONCLUSION

Our study indicated that exposure to both BPA and its substitutions could alter sex hormone levels. This finding supports the possibility that human exposure to bisphenols at environmental levels might affect the endogenous hormone balance.

Bisphenol A analogues in associations with serum hormone levels among reproductive-aged Chinese men

BACKGROUND

Bisphenol A (BPA) as an endocrine disrupting chemical has been shown to alter reproductive endocrine function, but little is known on its analogues such as bisphenol F (BPF) and bisphenol S (BPS) with increasing usage and exposure.

OBJECTIVE

To explore the associations between exposures to BPA, BPF and BPS and serum reproductive hormones among reproductive-aged Chinese men.

METHODS

We measured BPA, BPF and BPS concentrations in repeated urine samples and multiple reproductive hormones in the serum samples collected from 462 men attending an infertility clinic in Wuhan, China. Linear regression models were applied to assess the associations between averaged urinary BPA, BPF and BPS levels and serum hormone concentrations, and restricted cubic spline (RCS) models were further utilized to explore potential non-linear associations. We also examined potential modifying effects by age and body mass index (BMI).

RESULTS

There was little evidence of associations between BPA exposure and altered reproductive hormones. However, we found that elevated BPF and BPS exposures were in negative associations with estrogen (E2) levels and E2/T (total testosterone) ratio (all P for trends < 0.05), and that elevated BPS exposure was negatively associated with SHBG levels (P for trend = 0.09). Based on the RCS models, these linear negative associations except that between BPS exposure and E2/T ratio were further confirmed. In stratified analyses, BPF and BPS exposures in relation to reduced E2 and E2/T ratio were more pronounced among men aged > 30 years, whereas their associations with reduced SHBG levels were more pronounced among men aged ≤ 30. Also, BPS exposure in negative association with FSH only emerged among men with BMI ≥ 24 kg/m² (P for interaction = 0.03).

CONCLUSION

BPF and BPS exposures were negatively associated with male serum E2, E2/T ratio and SHBG levels, and these associations varied by age and BMI.

Bisphenol S Impairs Oestradiol Secretion during In Vitro Basal Folliculogenesis in a Mono-Ovulatory Species Model

Bisphenol S (BPS) affects terminal folliculogenesis by impairing steroidogenesis in granulosa cells from different species. Nevertheless, limited data are available on its effects during basal folliculogenesis. In this study, we evaluate in vitro the effects of a long-term BPS exposure on a model of basal follicular development in a mono-ovulatory species. We cultured ovine preantral follicles (180−240 μm, n = 168) with BPS (0.1 μM (possible human exposure dose) or 10 μM (high dose)) and monitored antrum appearance and follicular survival and growth for 15 days. We measured hormonal secretions (oestradiol (at day 13 [D13]), progesterone and anti-Müllerian hormone [D15]) and expression of key follicular development and redox status genes (D15) in medium and whole follicles, respectively. BPS (0.1 µM) decreased oestradiol secretion compared with the control (−48.8%, p < 0.001), without significantly impairing antrum appearance, follicular survival and growth, anti-Müllerian hormone and progesterone secretion and target gene expression. Thus, BPS could also impair oestradiol secretion during basal folliculogenesis as it is the case during terminal folliculogenesis. It questions the use of BPS as a safe BPA substitute in the human environment. More studies are required to elucidate mechanisms of action of BPS and its effects throughout basal follicular development.

From target analysis to suspect and non-target screening of endocrine-disrupting compounds in human urine

In the present work, a target analysis method for simultaneously determining 24 diverse endocrine-disrupting compounds (EDCs) in urine (benzophenones, bisphenols, parabens, phthalates and antibacterials) was developed. The target analysis approach (including enzymatic hydrolysis, clean-up by solid-phase extraction and analysis by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS)) was optimized, validated and applied to volunteers’ samples, in which 67% of the target EDCs were quantified. For instance, benzophenone-3 (0.2–13 ng g⁻¹), bisphenol A (7.7–13.7 ng g⁻¹), methyl 3,5-dihydroxybenzoate (8–254 ng g⁻¹), mono butyl phthalate (2–17 ng g⁻¹) and triclosan (0.3–9 ng g⁻¹) were found at the highest concentrations, but the presence of other analogues was detected as well. The developed target method was further extended to suspect and non-target screening (SNTS) by means of LC coupled to high-resolution MS/MS. First, well-defined workflows for SNTS were validated by applying the previously developed method to an extended list of compounds (83), and then, to the same real urine samples. From a list of approximately 4000 suspects, 33 were annotated at levels from 1 to 3, with food additives/ingredients and personal care products being the most abundant ones. In the non-target approach, the search was limited to molecules containing S, Cl and/or Br atoms, annotating 4 pharmaceuticals. The results from this study showed that the combination of the lower limits of detection of MS/MS and the identification power of high-resolution MS/MS is still compulsory for a more accurate definition of human exposome in urine samples.