Bisphenol-A in the European Prospective Investigation into Cancer and Nutrition cohort in Spain: Levels at recruitment and associated dietary factors

Distribution and potential risk factors of bisphenol a in serum and urine among Chinese from 2004 to 2019

Background

Bisphenol A (BPA) is an oil-derived, large-market volume chemical with endocrine disrupting properties and reproductive toxicity. Moreover, BPA is frequently used in food contact materials, has been extensively researched recently, and widespread exposure in the general population has been reported worldwide. However, national information on BPA levels in general Chinese people is lacking.

Methods

This study collected and analyzed 145 (104 in urine and 41 in serum) research articles published between 2004 and 2021 to reflect the BPA internal exposure levels in Chinese populations. The Monte Carlo simulation method is employed to analyze and estimate the data in order to rectify the deviation caused by a skewed distribution.

Results

Data on BPA concentrations in urine and serum were collected from 2006 to 2019 and 2004 to 2019, respectively. Urinary BPA concentrations did not vary significantly until 2017, with the highest concentration occurring from 2018 to 2019 (2.90 ng/mL). The serum BPA concentration decreased to the nadir of 1.07 ng/mL in 2011 and gradually increased to 2.54 ng/mL. Nationally, 18 provinces were studied, with Guangdong (3.50 ng/mL), Zhejiang (2.57 ng/mL), and Fujian (2.15 ng/mL) having the highest urine BPA levels. Serum BPA was investigated in 15 provinces; Jiangsu (9.14 ng/mL) and Shandong (5.80 ng/mL) were relatively high. The results also indicated that males' urine and serum BPA levels were higher than females, while the BPA levels in children were also higher than in adults (p < 0.001). Furthermore, the volume of garbage disposal (r = 0.39, p < 0.05), household sewage (r = 0.34, p < 0.05), and waste incineration content (r = 0.35, p < 0.05) exhibited a strong positive connection with urine BPA levels in Chinese individuals.

Conclusion

Despite using a data consolidation approach, our study found that the Chinese population was exposed to significant amounts of BPA, and males having a higher level than females. Besides, the levels of BPA exposure are influenced by the volume of garbage disposal, household sewage, and waste incineration content.

Relationship between exposure to parabens and benzophenones and prostate cancer risk in the EPIC-Spain cohort

The etiology of prostate cancer is not fully elucidated. Among environmental risk factors, endocrine-disrupting chemicals (EDCs) deserve special mention, as they alter metabolic pathways involved in hormone-dependent cancers. Epidemiological evidence assessing the carcinogenicity of EDCs is scarce. The aim of this study was to analyze the relationship between exposure to parabens and benzophenones and prostate cancer risk. We conducted a case-cohort study nested within the EPIC-Spain prospective multi-center cohort. Study population comprised 1,838 sub-cohort participants and 467 non-sub-cohort prostate cancer cases. Serum concentrations of four parabens and two benzophenones were assessed at recruitment. Covariates included age, physical activity, tobacco smoking, alcohol consumption, body mass index, educational level and diabetes. Borgan II weighted Cox proportional hazard models stratified by study center were applied. Median follow-up time was 18.6 years (range = 1.0-21.7 years). Most sub-cohort participants reached primary education at most (65.5%), were overweight (57.7%) and had a low level of physical activity (51.3%). Detection percentages varied widely, being lowest for butyl-paraben (11.3%) and highest for methyl-paraben (80.7%), which also showed the highest geometric mean (0.95 ng/ml). Cases showed significantly higher concentrations of methyl-paraben (p = 0.041) and propyl-paraben (p < 0.001). In the multivariable analysis, methyl-paraben - log-transformed (HR = 1.07; 95%CI = 1.01-1.12) and categorized into tertiles (HR = 1.60 for T3; 95%CI = 1.16-2.20) -, butyl-paraben - linear (HR = 1.19; 95%CI = 1.14-1.23) and log-transformed (HR = 1.17; 95%CI = 1.01-1.35) - and total parabens - log-transformed (HR = 1.09; 95%CI = 1.02-1.17) and categorized into tertiles (HR = 1.62 for T3; 95%CI = 1.10-2.40) - were associated with an increased prostate cancer risk. In this study, higher concentrations of methyl-, butyl-, and total parabens were positively associated with prostate cancer risk. Further research is warranted to confirm these findings.

Teratogenic and neuro-behavioural toxic effects of bisphenol A (BPA) and B (BPB) on Xenopus laevis development

Bisphenol A (BPA) is a plastic additive with endocrine disruptive activity, classified in 2017 by EU ECHA as substance of very high concern. A correlation between environmental exposure to BPA and congenital defects has been described in humans and in experimental species, including the amphibian Xenopus laevis. Among BPA analogues, bisphenol B (BPB) is used as alternative in different not-EU countries, including US, but seems to share with BPA its endocrine disruptor properties. Aim of the present work is the evaluation of the effects of BPB versus BPA exposure in a X. laevis developmental model. A windowed exposure (R-FETAX method) was applied covering the developmental phylotypic period (teratogenicity window), or the late tailbud stages (neuro-behavioural toxicity window, corresponding to the spontaneous swimming acquisition period). Samples were monitored for lethal effects during the full test period. External morphology evaluation and deglutition functional test were applied in any group. Abnormal tadpoles were also processed for cartilage staining. In groups exposed during neuro-behavioural toxicity window the swimming test was also applied. Lethality and malformations were obtained only in samples exposed during the teratogenicity window; these data were modelled using PROAST software and BPB relative potency resulted about 3 times higher than BPA. The day-by-day evaluation revealed that lethality was correlated to embryonic abnormal development of gills and apoptosis in gill primordia. Teratogenicity was never detected in groups exposed during the neuro-behavioural toxicity window, where some significant neuro-behavioural deficits were detected in tadpoles exposed to the highest tested concentrations of BPA and BPB.

New Evidence on BPA's Role in Adipose Tissue Development of Proinflammatory Processes and Its Relationship with Obesity

Bisphenol A (BPA) is a xenobiotic with endocrine disruptor properties which interacts with various receptors, eliciting a cellular response. In the plastic industry, BPA is widely used in the production of polycarbonate and epoxy-phenolic resins to provide elastic properties. It can be found in the lining of canned foods, certain plastic containers, thermal printing papers, composite dental fillings, and medical devices, among other things. Therefore, it is a compound that, directly or indirectly, is in daily contact with the human organism. BPA is postulated to be a factor responsible for the global epidemic of obesity and non-communicable chronic diseases, belonging to the obesogenic and diabetogenic group of compounds. Hence, this endocrine disruptor may be responsible for the development of metabolic disorders, promoting in fat cells an increase in proinflammatory pathways and upregulating the expression and release of certain cytokines, such as IL6, IL1β, and TNFα. These, in turn, at a systemic and local level, are associated with a chronic low-grade inflammatory state, which allows the perpetuation of the typical physiological complications of obesity.

Development and evaluation of a novel dietary bisphenol A (BPA) exposure risk tool

BACKGROUND

Exposure to endocrine disrupting chemicals such as bisphenol A (BPA) is primarily from the diet through canned foods. Characterizing dietary exposures can be conducted through biomonitoring and dietary surveys; however, these methods can be time-consuming and challenging to implement.

METHODS

We developed a novel dietary exposure risk questionnaire to evaluate BPA exposure and compared these results to 24-hr dietary recall data from participants (n = 404) of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study, a dietary clinical trial, to validate questionnaire responses. High BPA exposure foods were identified from the dietary recalls and used to estimate BPA exposure. Linear regression models estimated the association between exposure to BPA and questionnaire responses. A composite risk score was developed to summarize questionnaire responses.

RESULTS

In questionnaire data, 65% of participants ate canned food every week. A composite exposure score validated that the dietary exposure risk questionnaire captured increasing BPA exposure. In the linear regression models, utilizing questionnaire responses vs. 24-hr dietary recall data, participants eating canned foods 1-2 times/week (vs. never) consumed 0.78 more servings (p < 0.001) of high BPA exposure foods, and those eating canned foods 3+ times/week (vs. never) consumed 0.89 more servings (p = 0.013) of high BPA exposure foods. Participants eating 3+ packaged items/day (vs. never) consumed 62.65 more total grams of high BPA exposure food (p = 0.036).

CONCLUSIONS

Dietary exposure risk questionnaires may provide an efficient alternative approach to 24-hour dietary recalls to quantify dietary BPA exposure with low participant burden.

TRIAL REGISTRATION

The trial was prospectively registered at clinicaltrials.gov as NCT01826591 on April 8, 2013.

BPA disrupts meiosis I in oogonia by acting on pathways including cell cycle regulation, meiosis initiation and spindle assembly

The negative in utero effects of bisphenol A (BPA) on female reproduction are of concern since the ovarian reserve of primordial follicles is constituted during the fetal period. This time-window is difficult to access, particularly in humans. Animal models and explant culture systems are, therefore, vital tools for investigating EDC impacts on primordial germ cells (PGCs). Here, we investigated the effects of BPA on prophase I meiosis in the fetal sheep ovary. We established an in vitro model of early gametogenesis through retinoic acid (RA)-induced differentiation of sheep PGCs that progressed through meiosis. Using this system, we demonstrated that BPA (3×10^-7 M & 3×10^-5M) exposure for 20 days disrupted meiotic initiation and completion in sheep oogonia and induced transcriptomic modifications of exposed explants. After exposure to the lowest concentrations of BPA (3×10^-7M), only 2 probes were significantly up-regulated corresponding to NR2F1 and TMEM167A transcripts. In contrast, after exposure to 3×10^-5M BPA, 446 probes were deregulated, 225 were down- and 221 were up-regulated following microarray analysis. Gene Ontology (GO) annotations of differentially expressed genes revealed that pathways mainly affected were involved in cell-cycle phase transition, meiosis and spindle assembly. Differences in key gene expression within each pathway were validated by qRT-PCR. This study provides a novel model for direct examination of the molecular pathways of environmental toxicants on early female gametogenesis and novel insights into the mechanisms by which BPA affects meiosis I. BPA exposure could thereby disrupt ovarian reserve formation by inhibiting meiotic progression of oocytes I and consequently by increasing atresia of primordial follicles containing defective oocytes.

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.

Comparison of daily bisphenol A intake based on dietary and urinary levels in breastfeeding women

Bisphenol A (BPA) is an artificial chemical, and one of the significant external routes of daily BPA exposure is diet. Dietary BPA exposure can be calculated by urinary BPA concentration and dietary recall data. This cross-sectional study investigates exclusively breastfeeding women's BPA exposure by urinary total BPA concentration and nutritional records, including the 24 h Dietary Recall (HDR) and Food Frequency Questionnaire (FFQ). In this study, we included exclusively breastfeeding, healthy women volunteers (n = 80; 18-40 years), collected spot-morning urine samples and conducted a comprehensive face-to-face survey. Moreover, the women's urine BPA concentration was adjusted according to their urine creatinine concentrations. We assessed dietary BPA intake with the 24HDR and FFQ. Estimated daily BPA exposure according to urinary output volume and urinary creatinine concentration median values were 0.0507 and 0.06 μg/kg bw/day, respectively. Moreover, dietary BPA daily intake was found to be 0.17 and 0.95 μg/kg bw/day according to 24HDR data and FFQ data. The milk and dairy product group's and soft drinks group's contributions to the daily intake of BPA were 55.9 % and 25.92 %, respectively. The hazard ratio for BPA exposure was within limits according to references, including US EPA, Health Canada, and EFSA. This study indicates that BPA exposure, based on both total urinary BPA concentration and dietary recall data, was within the recommended daily intake level (4 μg/kg bw/day). However, further studies are required to understand the influence of seasonal, multicentre, and socioeconomic differences on BPA exposure.

Bisphenol-A exposure and risk of breast and prostate cancer in the Spanish European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Bisphenol A (BPA) is an endocrine disruptor that it is present in numerous products of daily use. The aim of this study was to assess the potential association of serum BPA concentrations and the risk of incident breast and prostate cancer in a sub-cohort of the Spanish European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

We designed a case-cohort study within the EPIC-Spain cohort. Study population consisted on 4812 participants from 4 EPIC-Spain centers (547 breast cancer cases, 575 prostate cancer cases and 3690 sub-cohort participants). BPA exposure was assessed by means of chemical analyses of serum samples collected at recruitment. Borgan II weighted Cox regression was used to estimate hazard ratios.

RESULTS

Median follow-up time in our study was 16.9 years. BPA geometric mean serum values of cases and sub-cohort were 1.12 ng/ml vs 1.10 ng/ml respectively for breast cancer and 1.33 ng/ml vs 1.29 ng/ml respectively for prostate cancer. When categorizing BPA into tertiles, a 40% increase in risk of prostate cancer for tertile 1 (p = 0.022), 37% increase for tertile 2 (p = 0.034) and 31% increase for tertile 3 (p = 0.072) was observed with respect to values bellow the limit of detection. No significant association was observed between BPA levels and breast cancer risk.

CONCLUSIONS

We found a similar percentage of detection of BPA among cases and sub-cohort from our population, and no association with breast cancer risk was observed. However, we found a higher risk of prostate cancer for the increase in serum BPA levels. Further investigation is needed to understand the influence of BPA in prostate cancer risk.

Endocrine disruption in Crohn's disease: Bisphenol A enhances systemic inflammatory response in patients with gut barrier translocation of dysbiotic microbiota products

The relevance of environmental triggers in Crohn's disease remains poorly explored, despite the well-known association between industrialization and disease onset/progression. We have aimed at evaluating the influence of endocrine disrupting chemicals in CD patients. We performed a prospective observational study on consecutive patients diagnosed of CD. Serum levels of endocrine disruptors, short-chain fatty acids, tryptophan and cytokines were measured. Bacterial-DNA and serum endotoxin levels were also evaluated. Gene expression of ER-α, ER-β and GPER was measured in PBMCs. All patients were genotyped for NOD2 and ATG16L1 polymorphisms. A series of 200 CD patients (140 in remission, 60 with active disease) was included in the study. Bisphenol A was significantly higher in patients with active disease versus remission and in colonic versus ileal disease. GPER was significantly increased in active patients and correlated with BPA levels. BPA was significantly increased in patients with bacterial-DNA and correlated with serum endotoxin levels, (r = 0.417; P = .003). Serum butyrate and tryptophan levels were significantly lower in patients with bacterial-DNA and an inverse relationship was present between them and BPA levels (r = -0.491; P = .001) (r = -0.611; P = .001). Serum BPA levels correlated with IL-23 (r = 0.807; P = .001) and IL-17A (r = 0.743; P = .001). The multivariate analysis revealed an independent significant contribution of BPA and bacterial-DNA to serum levels of IL-23 and IL-17A. In conclusion, bisphenol A significantly affects systemic inflammatory response in CD patients with gut barrier disruption and dysbiotic microbiota secretory products in blood. These results provide evidence of an endocrine disruptor playing an actual pathogenic role on CD.

Concentrations of bisphenol-A in adults from the general population: A systematic review and meta-analysis

BACKGROUND

Human bisphenol-A (BPA) exposure has been linked to adverse health effects even at low doses, which may be of potential public health concern.

OBJECTIVE

To summarize BPA concentrations in general human population and their variability according to sex, geographic area, and analytical method.

METHODS

Systematic review and meta-analysis of studies reporting BPA concentrations in adult human populations. Separate meta-analyses of median values were carried out for BPA in serum, creatinine-adjusted urinary BPA, and unadjusted urinary BPA concentrations using a random-effects model. Cochran's Q-statistic, I² index, 95% prediction intervals (PIs), between-studies standard deviation (τ), and forest plots were applied to verify study heterogeneity. Sensitivity and subgroup analyses and weighted ANOVAs and meta-regressions were conducted. Funnel plots and Egger's tests were used to examine publication bias.

RESULTS

Fifteen studies were included in the meta-analysis, totaling 28,353 participants. BPA was detected in over 90% of participants. The pooled creatinine-adjusted urinary BPA concentration was 1.76 μg/g (95% PI: 0.79-2.73), with individual estimates ranging between 1.20 and 2.41. The pooled estimate for unadjusted urinary BPA was 1.91 μg/l (95% PI: 0-3.97), ranging between 0.81 and 3.50, while the pooled estimate for serum BPA was 1.75 μg/l (95% PI: 0-10.58), ranging between 0.34 and 3.76. No differences were found by sex, geographic area or analytical technique. Larger sample sizes were associated with lower BPA concentrations. There was large heterogeneity across studies, whereas data for urinary BPA levels suggested a publication bias affecting research in low exposed populations.

CONCLUSION

This first meta-analysis of human BPA concentrations highlights a widespread population exposure to BPA. Although there was high heterogeneity across studies, the expected range of estimated human BPA concentrations suggests that potential health risks are unlikely. Further studies are warranted to better characterize the epidemiology of human BPA exposure, accounting for ethnic, geographic, individual and environmental variability.

Estimated Dietary Bisphenol-A Exposure and Adiposity in Samoan Mothers and Children

The Pacific Island nation of Samoa is marked by prevalent obesity and an increasing dependence on packaged foods likely to contain the endocrine disruptor bisphenol-A (BPA). We evaluated participant- and household-level characteristics associated with estimated dietary BPA exposure in Samoan mothers and their children and examined associations between dietary BPA exposure and body mass index (BMI) and abdominal circumference (AC). Dietary BPA exposure indices were estimated for 399 mother-child pairs by combining information from dietary questionnaires and relative concentrations of BPA measured in foods/beverages. We observed moderate to strong correlation between mother-child daily BPA indices (Spearman's rho = 0.7, p < 0.0001). In mothers, we observed lower daily BPA indices in those who were less physically active (p = 0.0004) and living in homes with higher income (p = 0.00001). In children, we observed lower daily BPA indices in those living in homes with higher income (p = 0.0003) and following a less modern dietary pattern (p = 0.002), and higher daily BPA indices in those who were less physically active (p = 0.02). No significant associations were observed between daily BPA indices and BMI or AC. Despite this, the application of the daily BPA index identified factors associated with dietary BPA exposure and warrants further examination in Samoa and other understudied populations.