Bisphenol A exposure and abnormal glucose tolerance during pregnancy: systematic review and meta-analysis.

In the present work, a systematic review and meta-analysis were performed to examine the probable relation between maternal exposure to bisphenol A (BPA), as estrogen-disrupting compounds, and gestational diabetes mellitus (GDM), and impaired glucose tolerance (IGT). We comprehensively searched three electronic databases to retrieve published studies on maternal exposure to BPA and GDM/IGT, through February 2021. Cochran's Q test and I2 statistics were employed for testing heterogeneity across studies. DerSimonian and Liard random-effects model was used to determine the pooled estimates. Otherwise, the fixed-effects model with inverse-variance weights was applied. Sensitivity analysis was performed to determine the robustness of the results by excluding each study from the pooled estimate. The potential publication bias was examined using Begg's and Egger's tests. The pooled odds ratio did not show BPA exposure to be a significant risk factor for GDM (OR = 0.90, 95% CI = 0.62-1.33, I2: 50.7%). Also, no significant association was observed between BPA exposure and risk of IGT (OR = 0.93, 95% CI = 0.40-2.18, I2: 11.5%). Based on the findings of this study, no association was found between exposure to BPA during pregnancy and the risk of GDM/IGT. Albeit no heterogeneity was found between studies.

Association of maternal exposure to bisphenol A with her ß-hCG level and neonatal anthropometric measures.

Bisphenol A (BPA) is one of the organic compounds that might interfere with estrogenic receptors, which would make difficulties in pregnancy hormones and fetal growth. Human chorionic gonadotropin (ß-hCG) is one of the important pregnancy hormones that might be affected by environmental pollutants. The aim of this study is to investigate the probable impacts of maternal exposure to BPA on anthropometric measures of newborns. This cross-sectional study was conducted in 2019-2020 in Isfahan, Iran. During the first trimester of pregnancy, we measured the urinary BPA concentration and serum ß-hCG level of 120 pregnant women, who were randomly selected from participants of a birth cohort. BPA concentration was measured using gas chromatography-mass spectrometry (GC-MS). Serum blood sample was derived and used for ß-hCG analysis. Anthropometric measurement of neonates was conducted at the time of birth. BPA and ß-hCG level were grouped by quartiles, and their associations with birth weight, height, and head circumference were tested using multiple linear regression model. The adjustment was done for urine creatinine, gender, and gestational age, as well as maternal age, body mass index, and education level. Data of 119 pairs of mothers and infants were available for the present study. The mean (SD) age of mothers was 29.19 (5.75) years; 56.3% of newborns were boys. Geometric mean of urinary BPA and ß-hCG concentrations were 0.36 ng/g crea. (creatinine) and 17736 mIU/ml, respectively. Across the BPA tertiles, the differences in mean values were not significant for none of the anthropometric measurements and gestational age (GA). Furthermore, no significant association existed between unadjusted and adjusted tertiles of BPA and ß-hCG with abovementioned birth outcomes. It seems that the non-significant association found in this study is because of low levels of urinary BPA levels than in other studies; the adverse effects on infants might be related to high concentration of BPA passed from placenta. Future longitudinal studies with large sample size are necessary to document the adverse health effects of maternal exposure to endocrine disruptor chemicals including BPA.

Application of UV/chlorine processes for the DR83:1 degradation from wastewater: Effect of coexisting anions.

In the present work, effect of coexisting anions on the degradation performance of UV/chlorine (UV/Cl) processes as an advanced oxidation treatment for the dye containing wastewater was investigated. The results showed that by increasing pH of the solution from 3 to 11, degradation efficiency of UV/Cl process was reduced from 96.2 ± 1.4% to 62.9 ± 3.1%. In the case of 100 mg/L of DR83:1, the removal efficiency was improved from 30.2 ± 1.5% to 93.3 ± 4.7% when the chlorine dose was increased from 100 to 1000 µM. The HCO3- and Br- ions were the main inhibitor and promotor anions responsible for the degradation of DR83:1. The relative contribution of Cl• was higher than that for HO• and UV, which was about three-times higher than that for HO•. The lowest and highest amounts of trihalomethanes were generated at acidic and alkaline conditions as well as low disinfection by products at low pH due to the generation of more HO• radicals at acidic pH in comparison to higher pH such that less intermediates were remained to react with chlorine.

Relationship of Urinary Phthalate Metabolites with Cardiometabolic Risk Factors and Oxidative Stress Markers in Children and Adolescents.

Introduction: Studies have proved that exposure of adults to phthalates might be related to cardiometabolic risk factors and changes in markers of oxidative stress. Such studies conducted on school-age children and adolescents are limited and fail to assess the simultaneous effect of phthalates on these risk factors and oxidative stress markers. Therefore, it was attempted to identify the relationship of urinary phthalate metabolites with cardiometabolic risk factors and oxidative stress markers in children and adolescents. Methods. In this cross-sectional study, 108 children and adolescents, living in Isfahan industrial city of Iran, were examined. Urine samples taken from the participants were analyzed for mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-exohexyl) phthalate (MEOHP), and mono-methyl phthalate (MMP). Results: Results showed that, among phthalate metabolites, MBP had the highest concentration, followed by MBzP, MEOHP, MEHHP, MEHP, and MMP. Concentrations of these metabolites had a significant relationship with some of the cardiometabolic risk factors including systolic blood pressure (SBP), fasting blood sugar (FBS), and triglycerides (TG) (p < 0.05). Furthermore, the crude and adjusted linear regression models indicated the significant association of phthalate metabolites with superoxide dismutase (SOD), malondialdehyde (MDA), and homeostasis model assessment of insulin resistance (HOMA-IR) (p < 0.05). Conclusion: Although urinary phthalate concentrations could not exactly reflect the long-term exposure level in the studied age groups, the consumption of phthalate-free products during childhood and adolescent development shall be assumed helpful in maintaining a healthy lifestyle. To confirm these findings and develop effective intervention strategies, it would be necessary to perform longitudinal studies on diverse population.

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

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

Maternal Exposure to Cadmium and Fetal Growth: a Systematic Review and Meta-Analysis.

This study aims to review the epidemiological studies on the association between cadmium (Cd) exposure during pregnancy and neonatal anthropometric measures. Electronic search of PubMed, Scopus, Web of Science, and Cochrane Collaboration was conducted till end of 2018. Pooled estimates were performed using a fixed-effects model or random-effects model. A total of 22 studies included in the meta-analyses. Subgroup analyses on sample type (maternal urine, maternal blood, cord blood, and placenta), meta-regression, and sensitivity analysis were performed to seek the sources of heterogeneity. In the random-effects meta-analysis of included studies, the pooled correlation coefficient between maternal exposure to Cd with birth weight was - 0.04 [95% CI (- 0.07, - 0.01), with birth length and head circumference as - 0.01 [95% CI (- 0.04, 0.02)] and - 0.02 [95% CI (- 0.06, 0.02)]. Our findings showed significant relationship between Cd exposure of pregnant women with low birth weight, but not with birth length and head circumference.

Systematic review and meta-analysis on the association between phthalates exposure and insulin resistance.

This study aims to provide an overview of human studies on the association of exposure to phthalates and insulin resistance. We systematically searched human studies available until 15 January 2018.We conducted a literature search in Scopus, ISI Web of Science, PubMed, Google Scholar, and Cochrane Collaboration. We used the following keywords to identify relevant articles: "phthalate", "phthalate ester", "metabolic syndrome", "insulin resistance", "glucose intolerance", and "diabetes". For analyzing data, we conducted meta-analysis using the Stata software. We appraised each study to examine the sources of heterogeneity, including difference in clinical outcomes and exposure measurements. To determine the robustness and whether some of the factors have the highest impact on the results of the present meta-analysis, several sensitivity analyses were conducted. Sensitivity analysis showed that by removing studies with the highest weight and age groups, no change was observed in heterogeneity. Moreover, with excluding the study conducted in Europe, the results remained unchanged and constant. In addition, the funnel plot and Egger's tests were executed to access publication bias. Both the funnel plots and Egger's test did not show any evidence of publication bias (P = 0.31). In the random effects meta-analysis of all studies (n = 8), the pooled correlation coefficient between phthalate exposure and HOMA-IR was 0.10 (95% CI; 0.07-0.12, P < 0.001), with significant heterogeneity (P < 0.001, I2 = 85.5%). Our findings revealed positive association between exposure to phthalate metabolites and increased HOMA-IR; this association remained significant even after adjusting the analysis for multiple confounding variables.

Association of exposure to Bisphenol A with obesity and cardiometabolic risk factors in children and adolescents.

In this study, the association of exposure to Bisphenol A (BPA) with obesity and cardiometabolic risk factors was investigated on 132 children and adolescents aged 6-18 years living in Isfahan, Iran. Potential contributors to BPA exposure were assessed by a questionnaire. Total BPA was detected in urine samples of all participants without significant difference in boys and girls. The mean body mass index (BMI) and waist circumference (WC) increased significantly across the BPA tertiles (p for trend = < 0.001). Similar trend was documented for systolic blood pressure (SBP) and diastolic blood pressure (DBP) as well as fasting blood sugar. The risk of obesity was 12.48 times higher in participants in the third tertile of BPA than in others (95% CI: 3.36-46.39, p < 0.001). The current study showed significant association between BPA exposure with obesity and some cardiometabolic risk factors in children and adolescents, however, further longitudinal studies are necessary to evaluate the clinical effects of this finding. Abbreviations: BMI: Body Mass Index; BPA: Bisphenol A; BSTFA: N, O-Bistrifluoroacetamide; CDC: Centers for Disease Control and Prevention; CI: Circumference Interval; DBP: Diastolic Blood Pressure; DLLME: Dispersive liquid-liquid microextraction method; FBS: Fasting Blood Glucose; HDL: high-density lipoprotein cholesterol were; LDL: low-density lipoprotein cholesterol; OR: Odd Ratio; PA: Physical Activity; SBP: Systolic Blood Pressure; TC: total cholesterol; TG: triglycerides; WC: Waist Circumference.

Association of benzene exposure with insulin resistance, SOD, and MDA as markers of oxidative stress in children and adolescents.

Benzene is a ubiquitous environmental pollutant with various health effects. It is reported that benzene exposure might be associated with insulin resistance in elderly adults. The aim of this study is to investigate the association between urinary benzene metabolite, trans, trans-muconic acid (t,t-ma) and markers of oxidative stress and insulin resistance in children and adolescents. This cross-sectional study was conducted in 2017 among 86 children and adolescents, aged 6-18 years, living in Isfahan, Iran. t,t-ma was measured as urinary benzene metabolite and homeostasis model assessment (HOMA-IR) was determined as an index of insulin resistance. Moreover, malondialdehyde (MDA) and superoxide dismutase (SOD) were assessed as oxidative stress markers. We found significant association between insulin resistance, fasting blood glucose, and fasting blood insulin with t,t-ma (p values = 0.002, 0.03, and 0.001, respectively). Results of this study indicate that benzene metabolite in higher concentrations in comparison with lower concentrations is associated with increased risk of insulin resistance. Moreover, after adjustment for age, sex, and household passive smoking, statistically significant increase were documented in SOD and MDA (4.49- and 3.54-fold, respectively) in intermediate levels of t,t-ma vs. low levels of t,t-ma (p values = 0.01 and 0.034, respectively). To the best of our knowledge, this is the first study in its kind in the pediatric age group. It showed that benzene exposures, even in environmental levels, might be associated with insulin resistance and oxidative stress in children and adolescents. Further longitudinal studies are necessary to assess the clinical impacts of this finding.

Association of urinary concentrations of phthalate metabolites with cardiometabolic risk factors and obesity in children and adolescents.

This study aimed to investigate the association of urinary concentration of phthalate metabolites with obesity and cardiometabolic risk factors in a pediatric population. This study was conducted in 2016 on 242 children and adolescents, aged 6-18 years, living in Isfahan, Iran. Urinary concentration of mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), Mono-2-ethylhexyl phthalate (MEHP), Mono-methyl phthalate (MMP), Mono (2-ethyl-5-exohexyl) phthalate (MEOHP), and mono (2-ethyl-5hydroxyhexyl) phthalate (MEHHP) metabolites were determined. The association of these metabolites with obesity and cardiometabolic risk factors was examined using student t-test, linear and logistics regression tests. Of the 242 participants studied, 140 (57.9%) were girls and 102 (42.1%) were boys. The mean (SD) age of the population was 11.34 (2.55) years and no significant difference existed in terms of age (p-value = 0.374). MBzP, MBP, MMP were observed in urine samples of all subjects, and MEHP, MEOHP, and MEHHP were observed in 99.6, 95.87, and 96.28% of the subjects, respectively. Of the total participants, 15.2% (n = 37) were obese and 37.7% (n = 92) were overweight. According to the logistic regression analysis, except MEOHP, all other pollutants were significantly associated with obesity (OR adjusted >1, p-value ≤ 0.002). A significant association existed between MBP and elevated blood pressure [OR crude in tertile3 = 4.87 (CI: 1.02-23.32), p-value = 0.024]. MBzP and MEHP were significantly associated with obesity, elevated levels of triglyceride and blood pressure. Increase in MBzP metabolite in the 3rd tertile resulted to about 2.5-fold increase in triglyceride levels than the first tertile [OR multivariate adjusted = 2.7 (CI: 1.23-6.22)]. The findings of this study clearly showed the association between phthalate metabolites with obesity, cardiometabolic risk factors in children and adolescents, however further longitudinal studies are necessary to evaluate the clinical effects of this finding.

The Relationship between Perchlorate in Drinking Water and Cord Blood Thyroid Hormones: First Experience from Iran.

BACKGROUND: Considering the controversial information regarding the effects of perchlorate on thyroid function of high risk population as neonates, and given the high prevalence rate of thyroid disorders specially congenital hypothyroidism in our region, this study aims to investigate for the first time in Iran, the relationship between drinking groundwater perchlorate and cord blood thyroid hormones level in an industrial region. METHODS: In this cross-sectional study, drinking groundwater perchlorate level of rural areas of Zarinshahr, Isfahan was measured. Simultaneously, cord blood level of thyroid hormones of neonates born in the studied region was measured. Thyroid function test of neonates in regions with low and high perchlorate level were compared. RESULTS: In this study, 25 tap water samples were obtained for perchlorate measurement. Level of cord blood thyroid stimulating hormone (TSH), T4 and T3 of 25 neonates were measured. Mean (standard deviation) of perchlorate, TSH, T4 and T3 was 3.59 (5.10) µg/l, 7.81 (4.14) mIU/m, 6.06 (0.85) mg/dl, and 63.46 (17.53) mg/dl, respectively. Mean levels of thyroid function tests were not different in low (<5 µg/l) and high level of drinking ground water perchlorate (P > 0.05). CONCLUSIONS: Perchlorate did not appear to be related to thyroid function of neonates in the studied industrial region. It seems that iodine status of the regions, as well as other environmental contaminants and genetic background, could impact on its relation with thyroid function of neonates.