Urinary bisphenol A concentrations and the risk of obesity in Korean adults

Obesity aggravates neuroinflammatory and neurodegenerative effects of bisphenol A in female rats

Bisphenol A (BPA), a common plasticizer, is categorized as a neurotoxic compound. Its impact on individuals exhibits sex-linked variations. Several biological and environmental factors impact the degree of toxicity. Moreover, nutritional factors have profound influence on toxicity outcome. BPA has been demonstrated to be an obesogen. However, research on the potential role of obesity as a confounding factor in BPA toxicity is lacking. We studied the neurodegenerative effects in high-fat diet (HFD)-induced obese female rats after exposure to BPA (10 mg/L via drinking water for 90 days). Four groups were taken in this study - Control, HFD, HFD + BPA and BPA. Cognitive function was evaluated through novel object recognition (NOR) test. Inflammatory changes in brain, and changes in hormonal level, lipid profile, glucose tolerance, oxidative stress, and antioxidants were also determined. HFD + BPA group rats showed a significant decline in memory function in NOR test. The cerebral cortex (CC) of the brain showed increased neurodegenerative changes as measured by microtubule-associated protein-2 (MAP-2) accompanied by histopathological confirmation. The increased level of neuroinflammation was demonstrated by microglial activation (Iba-1) and protein expression of nuclear factor- kappa B (NF-КB) in the brain. Obesity also caused significant (p < 0.05) increase in lipid peroxidation accompanied by reduced activities of antioxidant enzymes (glutathione S-transferase, catalase and glutathione peroxidase) and decrease in reduced-glutathione (p < 0.05) when compared to non-obese rats with BPA treatment. Overall, study revealed that obesity serves as a risk factor in the toxicity of BPA which may exacerbate the progression of neurological diseases.

Relationship of bisphenol A substitutes bisphenol F and bisphenol S with adiponectin/leptin ratio among children from the environment and development of children cohort

BACKGROUND

Bisphenol A (BPA) is known as an obesogenic endocrine disruptor. Bisphenol S (BPS) and F (BPF) are substitutes that have recently replaced BPA.

OBJECTIVES

To investigate the relationships of urinary bisphenols (BPA, BPS and BPF) with adiposity measurements (obesity, BMI z-score, and fat mass), serum adipokine levels (adiponectin and leptin), and adiponectin/leptin ratio (A/L ratio) in 6- and 8-year-old children.

METHODS

A total of 561 children who participated in the Environment and Development of Children cohort (482 and 516 children visited at age 6 and 8, respectively) at Seoul National University Children's Hospital during 2015-2019 were included. Urinary BPA levels were log-transformed. BPS levels were categorized into three groups (non-detected, lower-half, and higher-half of detected), and BPF levels were classified into two groups (non-detected and detected).

RESULTS

The urinary BPS higher-half group had a higher BMI z-score (β = 0.160, P= 0.044), higher fat mass (β = 0.104, P< 0.001), lower adiponectin concentration (β =- 0.069, P< 0.001), higher leptin concentration (β = 0.360, P< 0.001), and lower A/L ratio (β =- 0.428, P< 0.001) compared with the non-detected group. The urinary BPF-detected group had a higher fat mass (β = 0.074, P< 0.001), lower adiponectin concentration (β =- 0.069, P< 0.001), higher leptin concentration (β = 0.360, P< 0.001), and lower A/L ratio (β =- 0.428, P< 0.001) compared with the non-detected group. The BPA levels showed no consistent associations with outcomes, except for isolated associations of BPA at age 6 with a higher BMI z-score at age 6 (P= 0.016) and leptin at age 8 (P= 0.021).

CONCLUSIONS

Increased exposure to BPS and BPF is associated with higher fat mass and leptin concentration, lower serum adiponectin, and lower A/L ratio in children. These findings suggest potential adverse effects of BPA substitutes on adiposity and adipokines. No consistent association of BPA exposure with outcomes could be partly explained by the decreasing BPA levels over time.

[New advances in exposomics-analysis methods and research paradigms based on chromatography-mass spectrometry]

The occurrence and development of human diseases are influenced by both genetic and environmental factors. Research models that describe disease occurrence only from the perspective of genetics present certain limitations. In recent years, effects of environment factors on the occurrence and development of diseases have attracted extensive attentions. Exposomics focuses on the measurement of all exposure factors in an individual's life and how these factors are related to disease development. Exposomics provides new ideas to promote studies on the relationship between human health and environmental factors. Environmental exposures are characterized with different physical and chemical properties, as well as very low concentrations in vivo, which contribute great challenges in the comprehensive measurement of chemical residues in the human body. Chromatography-mass spectrometry-based technologies combine the high-efficiency separation ability of chromatography with the high resolution and sensitive detection characteristics of mass spectrometry; the combination of these techniques can achieve the high-coverage, high-throughput, and sensitive detection of environmental exposures, thus providing a powerful tool for measuring chemical exposures. Exposomics-analysis methods based on chromatography-mass spectrometry mainly include targeted quantitative analysis, suspect screening, and non-targeted screening. To explore the relationship between environmental exposure and the occurrence and development of diseases, researchers have developed research paradigms, including exposome wide association study, mixed-exposure study, exposomics and multi-omics (genome, transcriptome, proteome, metabolome)-association study, and so on. The emergence of these methods has brought about unprecedented developments in exposomics studies. In this manuscript, analytical methods based on chromatography-mass spectrometry, exposomics research paradigms, and their relevant prospects are reviewed.

Bisphenol A (BPA) and Cardiovascular or Cardiometabolic Diseases

Bisphenol A (BPA; 4,4'-isopropylidenediphenol) is a well-known endocrine disruptor. Most human exposure to BPA occurs through the consumption of BPA-contaminated foods. Cardiovascular or cardiometabolic diseases such as diabetes, obesity, hypertension, acute kidney disease, chronic kidney disease, and heart failure are the leading causes of death worldwide. Positive associations have been reported between blood or urinary BPA levels and cardiovascular or cardiometabolic diseases. BPA also induces disorders or dysfunctions in the tissues associated with these diseases through various cell signaling pathways. This review highlights the literature elucidating the relationship between BPA and various cardiovascular or cardiometabolic diseases and the potential mechanisms underlying BPA-mediated disorders or dysfunctions in tissues such as blood vessels, skeletal muscle, adipose tissue, liver, pancreas, kidney, and heart that are associated with these diseases.

Cross-sectional associations between phthalates, phenols, and parabens with metabolic syndrome risk during early-to-mid adolescence among a cohort of Mexican youth

BACKGROUND

Epidemiological studies on children and adults have linked toxicants from plastics and personal care products to metabolic disruption. Yet, the impact of endocrine-disrupting chemicals (EDCs) on adolescent metabolic syndrome (MetS) risk during early and mid-adolescence is unclear.

METHODS

To examine the links between exposure to EDCs and MetS risk and its components, cross-sectional data from 344 Mexican youth in early-to-mid adolescence (10-17 years) were analyzed. Urinary biomarker concentrations of phthalates, phenol, and paraben analytes were measured from a single spot urine sample collected in 2015; study personnel obtained anthropometric and metabolic measures. We examined associations between summary phthalates and metabolites, phenol, and paraben analytes with MetS risk z-scores using linear regression, adjusted for specific gravity, sex, age, pubertal status, smoking, alcohol intake, physical activity level, and screen time. As a secondary aim, mediation analysis was conducted to evaluate the role of hormones in the association between summary phthalates with lipids and MetS risk z-scores.

RESULTS

The mean (SD) age was 13.2 (1.9) years, and 50.9% were female. Sex-stratified analyses revealed associations between summary phthalates and lipids ratio z-scores, including Σ DEHP [β = 0.21 (95% CI: 0.04, 0.37; p < 0.01)], phthalates from plastic sources (Σ Plastic) [β = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], anti-androgenic phthalates (Σ AA) [β = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], and individual phthalate metabolites (MEHHP, MEOHP, and MECPP) among males. Among females, BPA [β = 0.24 (95% CI: 0.03, 0.44; p < 0.05)] was positively associated with lipids ratio z-score and one phenol (2,5 DCP) [β = 0.09 (95% CI: 0.01, 0.18); p < 0.05)] was associated with increased waist circumference z-score. Results showed no evidence of mediation by hormone concentrations in the association between summary phthalates with lipids ratio or MetS risk z-scores.

CONCLUSION

Higher EDC exposure was positively associated with serum lipids during adolescence, particularly among males.

G protein-coupled estrogen receptor activation by bisphenol-A disrupts lipid metabolism and induces ferroptosis in the liver

As a metabolic disruptor, bisphenol A (BPA) has been widely reported to disrupt lipid balance. Moreover, BPA has gained significant attention due to its estrogenic activity. While both ferroptosis and the G-protein-coupled estrogen receptor (GPER) have been implicated in lipid metabolism, their link to BPA-induced lipid accumulation remains unclear. In this study, chickens were randomly assigned to three groups and housed them for 4 weeks: a control group (0 μg/L BPA), a low dose group (50 μg/L BPA) and a high dose group (5000 μg/L BPA) to investigate the underlying mechanism of BPA-induced hepatotoxicity. Our results showed that BPA exposure significantly increased the contents of TG, TC, and LDL-C while decreasing HDL-C levels. We also found that BPA treatment altered the levels of genes involved in fatty acid β-oxidation (ampkα, cpt-1, and ppaα), synthesis (acc, fas, scd-1, and srebp-1) and absorption (lpl and cd36). Moreover, the results showed that the BPA group had higher levels of IL-1β, IL-18 and TNF-α. These results indicated that BPA exposure disrupted lipid metabolism and induced inflammation in the liver. We also demonstrated that BPA caused hepatic ferroptosis by raising iron content and the expression of genes related to lipid peroxidation (lpcat3, acsl4 and alox15), while reducing the expression of antioxidant system-associated genes (gpx4, slc7a11 and slc3a2). Importantly, BPA remarkably activated GPER expression in the liver. Interestingly, inhibition of GPER remarkably ameliorated BPA-induced lipid metabolism disorder, inflammatory response, and ferroptosis, indicating the crucial role of GPER in BPA-induced liver abnormalities. These findings highlight the link between GPER and ferroptosis in BPA-induced hepatotoxicity, providing new insights into the potential hazard of BPA.

Exposure to Bisphenol A and Its Analogs among Thai School-Age Children

Bisphenol F (BPF) and bisphenol S (BPS) have become popular substitutes for bisphenol A (BPA) in the plastic industry due to concerns over BPA's adverse effects. However, there is limited information on children's exposure to these chemicals. This study aims to assess the extent of BPA, BPF, and BPS exposure and determine factors that influence such exposure. A group of Thai children (age 6-13 years, N = 358) were recruited between October 2019 and 2020. Two first-morning voids were collected one week apart. Demographic and exposure-related information was gathered. Urinary concentrations of bisphenols were analyzed by liquid chromatography and tandem mass spectrometry. Correlation between bisphenol concentrations with age, body weight, and sources of bisphenol exposure, was determined using generalized estimating equations with linear model. BPA, BPF, and BPS were detected at 79.6%, 31.0%, and 16.8%, with geometric mean (GM) concentrations of 1.41, 0.013, and 0.014 ng/mL, respectively. Younger children aged <10 years exhibited 1.3-1.6 times higher GM levels of all bisphenols compared to older children. Exposure to food stored in plastic containers was associated with higher levels of BPF and BPS. In conclusion, BPA was the most frequently detected bisphenol in urine samples from Thai children, followed by BPF and BPS.

In vivo effects of low dose prenatal bisphenol A exposure on adiposity in male and female ICR offspring

BACKGROUND

Bisphenol A (BPA) is known to exhibit endocrine disrupting activities and is associated with adiposity. We examined the obesogenic effect of prenatal BPA exposure in the present study.

METHODS

Pregnant ICR mice were exposed to vehicle or BPA via the drinking water at a dose of 0.5 μg/kg·d throughout the gestation. Obesity-related indexes were investigated in the 12-wk-old offspring. Primary mouse embryonic fibroblasts (MEFs) collected from treated embryos were used to test effects of BPA on adipocyte differentiation.

RESULTS

Offspring presented a significantly higher rate of weight gain than the control, with impaired insulin sensitivity and increased adipocyte size. Differentiation of MEFs from BPA-treated mice showed a higher propensity for the adipocyte commitment as well as up-regulation of genes enriched in lipid biosynthesis. TGF-β signaling pathway was found to modulate obesogenic effect of BPA in MEF model, but estrogen signaling pathway had no effect.

CONCLUSIONS

The present study provides strong evidence of the association between prenatal exposure to low dose of BPA and a significant increase in body weight in the offspring mice with a critical role played by TGF-β signaling pathway. The potential interactions modulating the binding of BPA and TGF-β that activate its obesogenic effects need to be examined.

Environmental phenol exposure associates with urine metabolome alteration in young Northeast Indian females

Urinary biomonitoring delivers the most accurate environmental phenols exposure assessment. However, environmental phenol exposure-related biomarkers are required to improve risk assessment to understand the internal processes perturbed, which may link exposure to specific health outcomes. This study aimed to investigate the association between environmental phenols exposure and the metabolome of young adult females from India. Urinary metabolomics was performed using liquid chromatography-mass spectrometry. Environmental phenols-related metabolic biomarkers were investigated by comparing the low and high exposure of environmental phenols. Seven potential biomarkers, namely histidine, cysteine-s-sulfate, 12-KETE, malonic acid, p-hydroxybenzoic acid, PE (36:2), and PS (36:0), were identified, revealing that environmental phenol exposure altered the metabolic pathways such as histidine metabolism, beta-Alanine metabolism, glycerophospholipid metabolism, and other pathways. This study also conceived an innovative strategy for the early prediction of diseases by combining urinary metabolomics with machine learning (ML) algorithms. The differential metabolites predictive accuracy by ML models was >80%. This is the first mass spectrometry-based metabolomics study on young adult females from India with environmental phenols exposure. The study is valuable in demonstrating multiple urine metabolic changes linked to environmental phenol exposure and a better understanding of the mechanisms behind environmental phenol-induced effects in young female adults.

Environmental endocrine disruptor Bisphenol A induces metabolic derailment and obesity via upregulating IL-17A in adipocytes

BACKGROUND

Bisphenol A (BPA), a ubiquitous environmental endocrine disruptor, has been extensively demonstrated to be associated with metabolic disorders, including obesity and type 2 diabetes mellitus. However, the underlying mechanism underpinning the environmental etiology of chronic metabolic disorders has not been sufficiently elucidated.

OBJECTIVES

This study is designed to explore the toxicological pathogenesis of chronic inflammation in BPA exposure during obesity.

METHODS

We investigated the role of IL-17A in the association of BPA exposure and obesity from human cross-sectional study to animal models, including genetically modified IL-17A^-/- mice.

RESULTS

Here, our work started from case-control observation that BPA exposure was significantly associated with risk of obesity (odds ratio = 4.72, 95%CI: 3.18 - 11.18, P < 0.01), metabolic disorder and levels of interleukin-17A (IL-17A) in human adipose (estimated changes β = 0.46, 95%CI: 0.15 - 1.01, P < 0.01) with bariatric surgery. Animal model fed with high-fat diet (HFD) confirmed that BPA exposure aggravated body weight gain and insulin resistance, concurrent with much heightened inflammatory responses in the adipose tissue including increase in IL-17A and macrophage polarization towards M1 stage. Genetically modified IL-17A ablated mice (IL-17A^-/-) showed reversed adipose tissue inflammation response, improved macrophage polarization homeostasis, along with insulin sensitivity in both HFD group alone or much more significantly the HFD + BPA group. Moreover, mediation analysis in human epidemiological investigation demonstrated that plasma IL-17A attributed up to 30.01% mediating role in the associations between BPA exposure and obesity risk.

DISCUSSION

This research paradigm from human to animal provides strong evidence for the elucidation of IL-17A moderating inflammation and insulin resistance in obesity. Such findings reiterate the obesogenic role of environmental endocrine disruptor BPA in metabolic disorders and unveils the potential toxicological mechanisms underpinning such effect.

Exposure to Bisphenol A Substitutes, Bisphenol S and Bisphenol F, and Its Association with Developing Obesity and Diabetes Mellitus: A Narrative Review

Bisphenol A, a well-known endocrine-disrupting chemical, has been replaced with its analogs bisphenol S (BPS) and bisphenol F (BPF) over the last decade due to health concerns. BPS and BPF are present in relatively high concentrations in different products, such as food products, personal care products, and sales receipts. Both BPS and BPF have similar structural and chemical properties to BPA; therefore, considerable scientific efforts have investigated the safety of their exposure. In this review, we summarize the findings of relevant epidemiological studies investigating the association between urinary concentrations of BPS and/or BPF with the incidence of obesity or diabetes. The results showed that BPS and BPF were detected in many urinary samples at median concentrations ranging from 0.03 to 0.4 µg·L-1. At this exposure level, BPS median urinary concentrations (0.4 µg·L-1) were associated with the development of obesity. At a lower exposure level (0.1-0.03 µg·L-1), two studies showed an association with developing diabetes. For BPF exposure, only one study showed an association with obesity. However, most of the reported studies only assessed BPS exposure levels. Furthermore, we also summarize the findings of experimental studies in vivo and in vitro regarding our aim; results support the possible obesogenic effects/metabolic disorders mediated by BPS and/or BPF exposure. Unexpectedly, BPS may promote worse obesogenic effects than BPA. In addition, the possible mode of action underlying the obesogenic effects of BPS might be attributed to various pathophysiological mechanisms, including estrogenic or androgenic activities, alterations in the gene expression of critical adipogenesis-related markers, and induction of oxidative stress and an inflammatory state. Furthermore, susceptibility to the adverse effects of BPS may be altered by sex differences according to the results of both epidemiological and experimental studies. However, the possible mode of action underlying these sex differences is still unclear. In conclusion, exposure to BPS or BPF may promote the development of obesity and diabetes. Future approaches are highly needed to assess the safety of BPS and BPF regarding their potential effects in promoting metabolic disturbances. Other studies in different populations and settings are highly suggested.

Analysis of Blood Biochemistry and Pituitary-Gonadal Histology after Chronic Exposure to Bisphenol-A of Mice

Bisphenol-A is an emerging pollutant that is widespread in the environment, and to which live beings are continuously and inadvertently exposed. It is a substance with an endocrine-disrupting capacity, causing alterations in the reproductive, immunological, and neurological systems, among others, as well as metabolic alterations. Our study aimed to assess its clinical signs, and effects on the most relevant blood biochemical parameters, and to evaluate pituitary and gonadal histology after a chronic exposure of adult mice to different BPA doses (0.5, 2, 4, 50 and 100 µg/kg BW/day) through their drinking water. The biochemical results showed that a marked significant reduction (p < 0.05) was produced in the levels of serum glucose, hypoproteinaemia and hypoalbuminemia in the groups exposed to the highest doses, whereas in the group exposed to 50 µg/kg BW/day the glucose and total protein levels dropped, and the animals exposed to 100 µg/kg BW/day experienced a diminution in albumin levels. In the case of the group exposed to 50 µg/kg BW/day, however, hypertriglyceridemia and hypercholesterolemia were determined, and the blood parameters indicating kidney alterations such as urea and creatinine experienced a significant increase (p < 0.05) with respect to the controls. Regarding the pituitary and gonads, none of the animals exposed presented histological alterations at the doses tested, giving similar images to those of the control group. These results suggest that continuous exposure to low BPA doses could trigger an inhibition of hepatic gluconeogenesis, which would result in a hypoglycaemic state, together with an induction of the enzymes responsible for lipidic synthesis, a mechanism by which the increase in the lipid and serum cholesterol levels could be explained. Likewise, the decline in the protein and albumin levels would be indicative of a possible hepatic alteration, and the increase in urea and creatinine would point to a possible renal perturbation, derived from continuous exposure to this xenobiotic. Based on our results, it could be said that chronic exposure to low BPA doses would not produce any clinical signs or histological pituitary-gonadal effects, but it could cause modifications in some blood biochemical parameters, that could initially indicate a possible hepatic and renal effect.

Factors of Obesity and Metabolically Healthy Obesity in Asia

The East Asian region (China, Japan, and South Korea) is comprised of almost 1.5 billion people and recent industrialization has brought with it a pandemic of rising obesity, even in children. As these countries are rapidly aging and functioning at sub-replacement birthrates, the burgeoning costs of obesity-related care may threaten socialized healthcare systems and quality of life. However, a condition called metabolically healthy obesity (MHO) has been found to be without immediate cardiopulmonary or diabetic risk. Thus, maintenance of the MHO condition for the obese in East Asia could buffer the burden of long-term obesity care on medical systems and knowledge of the biochemical, genetic, and physiological milieu associated with it could also provide new targets for intervention. Diverse physiological, psychological, environmental, and social factors play a role in obesogenesis and the transition of MHO to a metabolically unhealthy obesity. This review will give a broad survey of the various causes of obesity and MHO, with special emphasis on the East Asian population and studies from that region.

Improved method for the determination of endocrine-disrupting chemicals in urine of school-age children using microliquid-liquid extraction and UHPLC-MS/MS

The presence of endocrine-disrupting chemicals in our daily life is increasing every day and, by extension, human exposure and the consequences thereof. Among these substances are bisphenols and parabens. Urine is used to analyze the exposure. The determination of 12 bisphenol homologues and 6 parabens is proposed. A procedure based on a method previously developed by our research group in 2014 is improved. The extraction yield is higher, because the new protocol is 5 times more efficient. Also, a comparison between calibration with pure standards and matrix calibration, to calculate the matrix effect, was also made. A high grade of matrix effect for all analytes was observed. In terms of validation, the limits of detection (LOD) were between 0.03 and 0.3 ng mL^-1 and limits of quantification (LOQ) 0.1 to 1.0 ng mL^-1, respectively, and the recovery is higher than 86.4% and lower than 113.6%, with a RSD lower than 13.5% in all cases. A methodology for accurate and sensitive quantification of bisphenol homologues together with parabens in human urine using UHPLC-MS/MS was developed. The method was successfully applied to 30 urine samples from children.

Associations of Phthalate Metabolites and Bisphenol A Levels with Obesity in Children: The Korean National Environmental Health Survey (KoNEHS) 2015 to 2017

BACKGROUND

Phthalates and bisphenol A (BPA) are synthetic chemicals widely used in daily life. This study investigated urinary phthalate and BPA levels in Korean children and their associations with obesity.

METHODS

A total of 2,351 children aged 3 to 17 years who participated in the Korean National Environmental Health Survey 2015 to 2017 were included. Urinary dilution was corrected using covariate-adjusted standardization (CAS). We examined the geometric mean (GM) concentrations of urinary phthalate metabolites, including di (2-ethylhexyl) phthalate (DEHP) metabolites (mono [2-ethyl-5-hydroxyhexyl] phthalate, mono [2-ethyl-5-oxohexyl] phthalate, and mono [2-ethyl-5-carboxypentyl] phthalate [MECPP]), mono-benzyl-phthalate (MBzP), mono (carboxyoctyl) phthalate (MCOP), mono (carboxy-isononyl) phthalate (MCNP), mono (3-carboxypropyl) phthalate, and mono-n-butyl-phthalate (MnBP), and BPA. We also analyzed the odds ratio (OR) for obesity according to the quartiles of each analyte.

RESULTS

The urinary GM levels of DEHP metabolites and MnBP were notably higher among Korean children than among American, Canadian, and German children. The CAS-applied GM concentrations of most analytes, except for MBzP, MCOP, and MCNP, were higher in children aged 3 to 5 years than in those aged 6 to 17 years. The OR for obesity in the highest quartile of MECPP was significantly higher than in the lowest quartile after adjusting for covariates. However, the other phthalate metabolites and BPA were not significantly associated with obesity.

CONCLUSION

The concentrations of urinary DEHP metabolites and MnBP were higher in Korean children than in children in Western countries. Urinary MECPP exposure, but not other phthalates or BPA, showed a positive association with obesity in Korean children. Further studies are required to elucidate the causal relationships.

Pyrethroids exposure induces obesity and cardiometabolic diseases in a sex-different manner

People in the United States and around the world are widely exposed to pyrethroid pesticides. However, little is known about the effect of pyrethroids exposure on obesity in adults. This study examined the association between pyrethroids exposure and obesity in males and females and the role of obesity in the association of pyrethroids exposure with diabetes and cardiovascular disease (CVD). We used data from the National Health and Nutrition Examination Survey 1999-2002 and 2007-2014. Multivariate linear regression and logistic regression models were fitted to assess the association between urinary 3-Phenoxybenzoic Acid (3-PBA, a validated biomarker for pyrethroids exposure used in the primary analysis) and obesity. Mediation analyses were performed to investigate the mediation role of obesity on the associations of 3-PBA with diabetes and CVD. In this analysis, 7896 participants aged 20 years and above were included, of which 1235 (32.2%) males and 1623 (39.9%) females were diagnosed as obese. There was a significant interaction between sex and 3-PBA (P_interaction = 0.004) for the risk of obesity. Among females, participants in the highest tertile of urinary 3-PBA had higher odds of obesity (OR = 1.22, 95% CI: 1.00, 1.48) compared to those in the lowest tertile after adjusting for covariates. Among males, the association was not statistically significant. Similar trends were found in the associations of log-transformed urinary 3-PBA level with body mass index in males and females. Further, we found that, in males and females, obesity explained the effect of 3-PBA exposure on diabetes by 1.1% (P = 0.850) and 13.6% (P = 0.004), as well as cardiovascular diseases by 5.9% (P = 0.785) and 25.0% (P = 0.016), respectively. In conclusion, 3-PBA was significantly associated with a higher risk of obesity, especially in females. In addition, obesity partially mediated the associations of 3-PBA exposure with diabetes and CVD.

Mixtures modeling identifies heavy metals and pyrethroid insecticide metabolites associated with obesity

We aim to examine the association between chemical mixtures and obesity. Blood and urinary levels of tween-six chemicals were measured in adults who participated in the KoNEHS. We identified the associations of chemicals with obesity using linear regression models. Weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were conducted as secondary analyses. Of the 3,692 participants included in the analysis, 18.0% had obesity. In the logistic regression model, mercury (Hg), lead (Pb), and 3PBA levels were associated with obesity, and significant trends were observed for these chemical tertiles (p < 0.001). Hg, Pb, and 3PBA levels were also associated with BMI. The WQS index was significantly associated with both obesity (OR = 2.15, 95% CI: 2.11-2.20) and BMI (β = 0.39, 95% CI: 0.37-0.51). The qgcomp index also found a significant association between chemicals and both obesity (OR = 1.70, 95% CI: 1.56-1.85) and BMI (β = 0.40, 95% CI: 0.39-0.41). Hg, Pb, and 3PBA were the most heavily weighed chemicals in these models. In BKMR analysis, the overall effect of the mixture was significantly associated with obesity. Hg, Pb, and 3PBA showed positive trends and were observed as the most important factors associated with obesity. Given increasing exposure to chemicals, there is a need to investigate the associations between chemical exposures, either separately or together, and incident obesity risk factors in well-characterized cohorts of different populations, and to identify potential approaches to chemical exposure prevention.

Gestational bisphenol A exposure impairs hepatic lipid metabolism by altering mTOR/CRTC2/SREBP1 in male rat offspring

Lipid metabolism is an important biochemical process in the body. Recent studies have found that environmental endocrine disruptors play an important role in the regulation of lipid metabolism. Bisphenol A (BPA), a common environmental endocrine disruptor, has adverse effects on lipid metabolism, but the mechanism is still unclear. This study aimed to investigate the effects of gestational BPA exposure on hepatic lipid metabolism and its possible mechanism in male offspring. The pregnant Sprague-Dawley rats were exposed to BPA (0, 0.05, 0.5, 5 mg/kg/day) from day 5 to day 19 of gestation to investigate the levels of triglyceride (TG) and total cholesterol (TC), and the expression of liver lipid metabolism-related genes in male offspring rats. The results showed that compared with the control group, the TG and TC levels in serum and liver in BPA-exposed groups was increased. And the expressions of liver fatty acid oxidation related genes, such as peroxisome proliferators-activated receptor α (PPARα) and carnitine palmitoyl transferase 1α (CPT1α), were down-regulated. However, the expressions of fatty acid synthesis related genes, such as sterol regulatory element binding proteins 1 (SREBP-1), acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD-1), were up-regulated. The increased protein levels of mTOR and p-CRTC2 suggested that CREB-regulated transcription coactivator 2 (CRTC2) might be an important mediator in the mTOR/SREBP-1 pathway. In conclusion, these results demonstrated that mTOR/CRTC2/SREBP-1 could be affected by gestational BPA exposure, which may involve in the lipid metabolic disorders in later life.

The Effect of Bisphenol A on the IVF Outcomes Depending on the Polymorphism of the Detoxification System Genes

The aim of the study was to analyze the relationship between the level of bisphenol A (BPA) in the blood and follicular fluid, the polymorphism of the detoxification system genes, and the outcomes of IVF cycles. The data of 300 infertile patients with fresh IVF-ET cycles were analyzed. The level of BPA in the blood and follicular fluid was determined by HPLC-MRM-MS/MS. Determination of genotypes of the detoxification system genes was carried out by the real-time PCR. The threshold level for determining BPA was 0.1 ng/mL. BPA was detected in 92.3% (277/300) blood and in 16.8% (49/292) follicular fluid (FF) samples. There was no correlation between BPA level in the blood and FF. In patients with the absence of the A allele of the SULT1A1 gene, BPA was detected in FF significantly more often (22.6% vs. 13.5%, p = 0.0341). There was an association (not statistically significant) between the level of BPA in the blood and the presence of the G allele of the GSTP1 gene (rs1695) and the C allele in the GSTP1 gene (rs1138272). Our data suggests the role of detoxification system genes in the metabolism of BPA in the human body. The influence of BPA and detoxification system genes on the IVF outcomes requires further research.