Neonatal outcomes of intrauterine nonylphenol exposure--a longitudinal cohort study in Taiwan

Endocrine disrupting chemicals: gestational diabetes and beyond

Gestational Diabetes Mellitus (GDM) has been on the rise for the last two decades along with the growing incidence of obesity. The ubiquitous use of Endocrine-Disrupting Chemicals (EDCs) worldwide has been associated with this increase in GDM incidence. Epigenetic modifications such as DNA methylation, histone acetylation, and methylation have been associated with prenatal exposure to EDCs. EDC exposure can also drive a sustained disruption of the hypothalamus-pituitary-thyroid axis and various other signaling pathways such as thyroid signaling, PPARγ signaling, PI3K-AKT signaling. This disruption leads to impaired glucose metabolism, insulin resistance as well as β-cell dysfunction, which culminate into GDM. Persistent EDC exposure in pregnant women also increases adipogenesis, which results in gestational weight gain. Importantly, pregnant mothers transfer these EDCs to the fetus via the placenta, thus leading to other pregnancy-associated complications such as intrauterine growth restriction (IUGR), and large for gestational age neonates. Furthermore, this early EDC exposure of the fetus increases the susceptibility of the infant to metabolic diseases in early life. The transgenerational impact of EDCs is also associated with higher vascular tone, cognitive aberrations, and enhanced susceptibility to lifestyle disorders including reproductive health anomalies. The review focuses on the impact of environmental toxins in inducing epigenetic alterations and increasing the susceptibility to metabolic diseases during pregnancy needs to be extensively studied such that interventions can be developed to break this vicious cycle. Furthermore, the use of EDC-associated ExomiRs from the serum of patients can help in the early diagnosis of GDM, thereby leading to triaging of patients based on increasing risk factor of the clinicopathological condition.

Assessment of nonylphenol exposure based on global urinary concentration data and its risk analysis

Nonylphenol (NP) has been recognized as a priority hazardous substance because of its estrogenic activity and ubiquity in the environment. Therefore, it is important to understand the daily intake of NP in humans and evaluate the potential health risks of NP. The median or average estimated daily intake (EDI) of NP was estimated based on urinary NP or alkyl-chain-oxidized NP metabolites concentration data from published epidemiological studies. In brief, we acquired 34 peer-reviewed publications, which contained 14235 samples from twelve countries or regions. The global average estimated daily intake of NP was 1.003 μg/(kg bw·day), which was lower than the tolerable daily intake recommended by the Danish Veterinary and Food Authority [5 μg/(kg bw·day)]. Korea had the highest exposure level [3.471 μg/(kg bw·day)] among different countries or regions. Compared with the adult [0.743 μg/(kg bw·day)] and pregnant women [0.806 μg/(kg bw·day)] groups, the children group had the highest estimated daily intake of NP at 2.368 μg/(kg bw·day). Besides, the global NP risk hazard quotient was 0.201, and the risk hazard quotients of all countries or regions were less than 1. However, the global HQ value of the 95th quantile population was 2.299, which was much higher than 1, the potential health risk cannot be ignored and needs to be confirmed by more research. To our knowledge, this is the first study to assess the overall NP exposure levels based on published biomonitoring data, and has important implications for assessing the potential effects of NP exposure on human health. In addition, OH-NP is a robust and sensitive novel biomarker for NP, there are fewer studies on the application of this biomarker, and more studies are needed in the future for quantitative exposure and risk assessment of NP.

Association between prenatal exposure to alkylphenols and intelligence quotient among preschool children: sex-specific effects

BACKGROUND

While prenatal exposure to alkylphenols (APs) has been demonstrated to be associated with neurodevelopmental impairments in animals, the evidence from epidemiological studies remains limited and inconclusive. This study aimed to explore the link between AP exposure during pregnancy and the intelligence quotient (IQ) of preschool children.

METHODS

A total of 221 mother-child pairs from the Guangxi Zhuang Birth Cohort were recruited. Nonylphenol (NP), 4-tert-octylphenol (4-T-OP), 4-n-nonylphenol (4-N-NP), and 4-n-octylphenol were measured in maternal serum in early pregnancy. Childhood IQ was evaluated by the Fourth Edition of Wechsler Preschool and Primary Scale of the Intelligence at 3 to 6 years of age. The impact of APs on childhood IQ were evaluated by generalized linear models (GLMs), restricted cubic spline (RCS), and Bayesian kernel machine regression (BKMR).

RESULTS

In GLMs, prenatal exposure to NP and the second tertile of 4-T-OP exhibited an inverse association with full-scale IQ (FSIQ) (β = -2.38; 95% CI: -4.59, -0.16) and working memory index (WMI) (β = -5.24; 95% CI: -9.58, -0.89), respectively. Prenatal exposure to the third tertile of 4-N-NP showed a positive association with the fluid reasoning index (β = 4.95; 95% CI: 1.14, 8.77) in total children, as well as in girls when stratified by sex. A U-shaped relationship between maternal 4-T-OP and WMI was noted in total children and girls by RCS (all P nonlinear < 0.05). The combined effect primarily driven by NP, of maternal AP mixtures at concentrations above the 50th percentile exhibited an inverse trend on FSIQ in total children and girls in BKMR.

CONCLUSIONS

Prenatal exposure to various APs affects IQ in preschool children, and there may be nonmonotonic and sex-specific effects. Further investigation across the population is required to elucidate the potential neurotoxic effects of APs.

Relationship between exposure of alkylphenols in serum of pregnant women during early pregnancy and adverse birth outcomes

Alkylphenols are a type of endocrine disruptors, which are commonly found in personal care products, food, and water and are more harmful to the human body. To investigate the relationship between exposure of alkylphenols in serum of pregnant women during early pregnancy and adverse birth outcomes, a total of 2035 healthy pregnant women and their neonates were recruited in the birth cohort of Zhuang nationality in Guangxi from 2015 to 2018. The peripheral venous blood samples were collected from pregnant women in early pregnancy; the concentrations of nonylphenol (NP), 4-nonylphenol (4-N-NP), 4-tert-octylphenol (4-T-OP), and 4-n-octylphenol (4-N-OP) in serum were detected by ultra-performance liquid performance chromatography-tandem mass spectrometry (UPLC-MS). Binary logistic regression showed that NP [OR = 1.40 (95% CI: 1.00, 1.94)] was positively associated with preterm birth. Restricted cubic spline analyses showed that logNP and log4-T-OP had non-linearity associations with preterm birth (logNP: P_overall = 0.006, P_non-linear = 0.003; log4-T-OP: P_overall = 0.004, P_non-linear = 0.002). Multiple linear regression analysis showed that maternal serum concentration of NP was negatively associated with birth weight of perinatal infants (β = -14.68, 95% CI: -29.18, -0.19), which may be sensitive in male neonates (β = -26.18, 95% CI: -47.33, -5.02). The findings demonstrate that nonylphenol is a risk factor of preterm birth, and nonylphenol is negatively associated with the birth weight in male infants.

Impact of Chemical Endocrine Disruptors and Hormone Modulators on the Endocrine System

There is growing concern regarding the health and safety issues of endocrine-disrupting chemicals (EDCs). Long-term exposure to EDCs has alarming adverse health effects through both hormone-direct and hormone-indirect pathways. Non-chemical agents, including physical agents such as artificial light, radiation, temperature, and stress exposure, are currently poorly investigated, even though they can seriously affect the endocrine system, by modulation of hormonal action. Several mechanisms have been suggested to explain the interference of EDCs with hormonal activity. However, difficulty in quantifying the exposure, low standardization of studies, and the presence of confounding factors do not allow the establishment of a causal relationship between endocrine disorders and exposure to specific toxic agents. In this review, we focus on recent findings on the effects of EDCs and hormone system modulators on the endocrine system, including the thyroid, parathyroid glands, adrenal steroidogenesis, beta-cell function, and male and female reproductive function.

Nonylphenol exposure in 7-year-old Japanese children between 2012 and 2017- Estimation of daily intakes based on novel urinary metabolites

Nonylphenol (NP) has been under scrutiny for decades due to its endocrine-disrupting properties and its ubiquity in the environment. Despite its widespread occurrence, robust and reliable exposure data are rare. In this study, we used human biomonitoring (HBM) measuring the novel urinary alkyl-chain-oxidized biomarkers OH-NP and oxo-NP to determine NP exposure in 7-year-old Japanese children. The new biomarkers are advantageous over measuring unchanged NP because they are not prone to external contamination. We analyzed 180 first morning void urine samples collected between 2012 and 2017. OH-NP and oxo-NP were detected in 100% and 66% of samples at median concentrations of 2.69 and 0.36 µg/L, respectively. 10-fold concentration differences between OH-NP and oxo-NP are in line with recent findings on human NP metabolism. Based on OH-NP we back-calculated median and maximum NP daily intakes (DI) of 0.14 and 0.95 µg/(kg bw*d). These DIs are rather close to but still below the current provisional tolerable daily intake of 5 µg/(kg bw*d) by the Danish Environmental Protection Agency. Between 2012 and 2017 the DIs decreased by an average of 4.7% per year. We observed no seasonal changes or gender differences and questionnaire data on food consumption, housing characteristics or pesticide use showed no clear associations with NP exposure. Urinary OH-NP was weakly associated with the oxidative stress (lipid peroxidation) biomarkers N-ε-hexanoyl-lysine (HEL) and trans-4-hydroxy-2-nonenal (HNE) (Spearman ρ = 0.30 and 0.22, respectively), but not with 8-hydroxy-2'-deoxyguanosine (8-OHdG). Further research is needed to identify and understand the major sources of NP exposure and to investigate a potential role in oxidative stress. This study is the first to investigate NP exposure in Japanese children based on robust and sensitive HBM data. It is a first step to fill the long-standing gap in quantitative human NP exposure monitoring and risk assessment.

Impact of Nonylphenols and Polyhalogenated Compounds in Follicular Fluid on the Outcome of Intracytoplasmic Sperm Injection

Endocrine-disrupting chemicals (EDCs) interfere with the mammalian hormone system and alter its endo- and paracrine regulation. The goal of the present study was to examine the presence of 14 EDCs, including the technical mixture of nonylphenols and Mirex, in human follicular fluid (FF) and to find a potential correlation between endocrine active substances and a possible impact on female fertility. Furthermore, potential sources of EDC exposition regarding patients' lifestyle and socioeconomic factors were investigated. Human FF was collected from a total of 210 women undergoing intracytoplasmic sperm injection-treatment cycles because of male subfertility. The presence of EDCs was analyzed using gas chromatography coupled with mass spectrometry. Thirteen of the 14 investigated EDCs were present in every FF sample; compounds with the highest concentrations in FF were nonylphenol and Mirex. Nearly all kinds of EDCs led to significantly reduced maturation and fertilization rate. No significant influence of EDC concentration on the clinical pregnancy rate was observed for neither of the analyzed EDCs. Patients who obtained their clothes and textiles at fashion discounters displayed a higher amount of EDCs in their FF. In contrast, patients' residential area, source of food products, and nicotine or caffeine consumed were not associated with EDC accumulation. Clinicaltrials.gov NCT01385605 (11 July 2011).

Associations of urinary phenolic environmental estrogens exposure with blood glucose levels and gestational diabetes mellitus in Chinese pregnant women

BACKGROUND

Endocrine-disrupting chemicals (EDCs) are considered to be related to diabetes, but studies of the association between phenolic EDCs and gestational diabetes mellitus (GDM) are limited.

OBJECTIVES

To assess associations of maternal urinary bisphenol A (BPA), nonylphenol (NP), and 2-tert-octylphenol (2-t-OP) with GDM occurrence.

METHODS

A cross-sectional study was performed among 390 Chinese women at 24-28 weeks of gestation. GDM was diagnosed with a 2-h 75-g oral glucose tolerance test (OGTT). BPA, NP, and 2-t-OP concentrations were determined in urine samples. Linear and logistic regression tests evaluated associations of BPA, NP, and 2-t-OP with blood glucose levels and GDM prevalence.

RESULTS

The 2-t-OP concentrations in GDM patients were significantly higher than in non-GDM women with median values of 2.23 μg/g Cr and 1.79 μg/g Cr, respectively. No significant difference was observed in BPA and NP. Urinary 2-t-OP was positively associated with blood glucose levels after adjustment for several confounding factors and urinary BPA and NP. Higher 2-t-OP levels were associated with higher odds of GDM (OR: 5.78; 95% CI: 2.04, 16.37), whereas higher NP levels were associated with lower odds (OR: 0.22; 95% CI: 0.05, 0.85) in the adjusted models. In addition, compared to the first quartile of 2-t-OP, the adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for GDM in the second, third, and fourth quartiles were 2.81 (1.23, 6.42), 3.01 (1.30, 6.93), and 5.49 (2.24, 13.46), respectively.

CONCLUSION

Our study indicates that, for the first time to our knowledge, exposure to 2-t-OP is associated with a higher risk of GDM. However, higher NP exposure is associated with lower GDM risk. Further studies are necessary to affirm the associations of 2-t-OP and NP with GDM, and to elucidate the causality of these findings.

Prenatal urinary concentrations of environmental phenols and birth outcomes in the mother-infant pairs of Tehran Environment and Neurodevelopmental Disorders (TEND) cohort study

Daily exposure to environmental phenols can lead to potential undesirable effects on the health of pregnant women and fetuses. The present study is aimed to evaluate the relationship between maternal urinary concentrations of phenols in pregnancy and anthropometric birth outcomes. The studied population comprised of 189 pregnant women participating in the Tehran Environment and Neurodevelopmental Disorders (TEND) prospective cohort study, which had been ongoing since March 2016 in some hospitals and health care delivery centers in Tehran, Iran. Concentrations of bisphenol-A, triclosan, 4-nonylphenol, and parabens were determined in spot urine samples of pregnant mothers in the first trimester. Weight, length, and head circumference at birth were also extracted from the mothers' delivery files. Multivariable linear regression was used to examine the relationship between log-concentrations of phenols and birth outcomes. When we analyzed all samples regardless of neonates' gender, none of the urinary concentrations of phenols were associated with weight and length at birth. Indeed, in sex-stratified adjusted models, one log-unit increase of butylparaben was related to a 283.6 g (95% CI: 23, 544) increase in boys' birth weight. Prenatal urinary concentration of triclosan and propylparaben was respectively related to a decrease of 4.8 cm (95% C: -8.5, -1.1) in boys' length and 0.9 cm (95%CI: -1.8, -0.04) in girls' length. In the adjusted models for estimating the changes in head circumference, one log-unit increase of triclosan, methylparaben, and butylparaben led to a reduction of 1.6 cm (95% CI: -3.17, 0.03), increase of 0.8 cm (95% CI: -0.01, 1.6) and 0.7 cm (95% CI: 0.08, 1.4) in head circumference at birth respectively. Our results suggested that prenatal triclosan and parabens exposure might be associated with head circumference at birth. Furthermore, we observed a sexually dimorphic pattern between maternal triclosan and parabens exposure during pregnancy and fetal growth. However, these findings must be interpreted while taking into account the limitations of this study.

Bayesian inference of nonylphenol exposure for assessing human dietary risk

Nonylphenols (NPs) are endocrine-disrupting compounds commonly found in the environment and a number of food products. In this study, we constructed a probabilistic risk framework incorporating a Bayesian inference of exposure level in foodstuffs in conjunction with effect analysis of reproduction and renal disease. Our objective was to contrast the risk of dietary exposure to NPs among individuals in various age groups, with a particular focus on fertile females. In this study, seafood presented relatively high NP concentrations; however, seafood accounts for only a small proportion of the total food intake of most individuals. Rice was shown to make the largest contribution to NP daily intake among males and females in most age groups. Chicken made the largest contribution in the 12-16 and 16-18 year age groups. The mean average daily dose of NPs tended to decrease with age, regardless of gender. The estimated distribution of hazard quotients of <1 in all groups means that the risk of reproductive or renal abnormalities due to dietary exposure to NPs is negligible within most of the Taiwanese population. Nonetheless, preschoolers (3-6-year-olds) appear to be more vulnerable to NPs than do individuals in other age groups. There has been growing concern among researchers concerning the neurotoxic effects of NPs on offspring via maternal exposure. We recommend conducting a comprehensive assessment of exposure to NPs via multiple exposure routes, particularly among fertile women and preschoolers.

Bioaccumulation, metabolism, and risk assessment of phenolic endocrine disrupting chemicals in specific tissues of wild fish

Phenolic endocrine disrupting chemicals (EDCs) may pose a great hazard to wildlife and humans, owing to their ubiquitous presence in the environment and potential bioaccumulation ability. We investigated the bioaccumulation, metabolism, and human health risks of six phenolic EDCs, including bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2), in wild fish from the Pearl River system, South China. Except EE2, the other five EDCs were detected in at least one of the four fish tissues (bile, liver, plasma, and muscle). The concentrations of BPA and 4-NP were greater than those of 4-t-OP, E1, and E2 in all tissues. The median values of log bioaccumulation factors for EDCs at the range of 3.86-4.52 in bile, 2.06-3.16 in liver, 2.69-3.87 in plasma, and 1.34-2.30 in muscle, indicating a higher bioaccumulation potential in fish bile than in other tissues. Greater levels of glucuronide/sulfate conjugated EDCs were found in fish bile and liver than in the plasma and muscle, suggesting that the liver and bile played an important role in the metabolism and excretion of phenolic EDCs in fish. The calculated hazard quotient values were below 1 for each compound, implying low risk to human health by intake of edible fish.

Interactive effects of nonylphenol and bisphenol A exposure with oxidative stress on fetal reproductive indices

Nonylphenol (NP) and/or bisphenol A (BPA) may have reproductive effects. Although the mechanisms of action remain unclear, steroid hormones biosynthesis, hypothalamus pituitary adrenal axis activity, oxidative stress, and crosstalk interaction of NP and BPA mixture and its pathways may play a contributory role. This cross-sectional study examined whether the interactive effects of NP/BPA and oxidative stress biomarkers played a role in reproductive indices (penis length and anogenital distance (AGD)) in 244 mother-fetus pairs. Four biomarkers of oxidative stress, (8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO₂Gua), 8-iso-prostaglandin F_2α (8-isoPF_2α), and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)) were simultaneously analyzed using the high-performance liquid chromatography-electrospray ionization tandem mass spectrometry method. No significant associations were found between reproductive indices and NP/BPA or oxidative stress biomarkers. Maternal exposure to a mixture of NP and BPA may enhance 8-OHdG. Interactive effects were found in the high 8-isoPF_2α group, and prenatal NP exposure was inversely associated with penis length (β = -3.68 mm; p = 0.01). Similar results were noted among boys who were born to mothers in the high 8-isoPF_2α group, in which BPA was inversely associated with penis length (β = -4.43 mm; p = 0.005). Our findings suggest important implications for prenatal exposure to oxidative stress, as evidenced by the 8-isoPF2α level. Thus, NP and BPA may interact to shape fetal reproductive tract development, particularly in boys. The interactive effects of NP/BPA, oxidative stress, and reproductive indices should be considered.

Evidence of high di(2-ethylhexyl) phthalate (DEHP) exposure due to tainted food intake in Taiwanese pregnant women and the health effects on birth outcomes

The contamination of a clouding agent with di(2-ethylhexyl) phthalate (DEHP), a substitute emulsifier-containing compound used in a variety of foods was announced on May 23, 2011. The aims of this study were as follows (1) compare the urine phthalates (PAE) metabolites concentration and estimate the daily intake (DI) of PAEs in pregnant women before and after the tainted food scandal and (2) examine the effect of relatively high PAEs exposure on birth outcome. One-hundred twelve pregnant women in Northern Taiwan participated in this study from March to December 2010, i.e., before the tainted food scandal. After the tainted food scandal, we collected 69, 73, and 180 urine specimens (January 2013 to August 2014) from women whom were in their first, second, and third trimesters of pregnancy, respectively. We measure urinary DEHP metabolite concentrations to estimate the DI of DEHP and the hazard quotient (HQ) of subjects. This was the first study to assess the effects of DEHP-tainted food scandal exposure in pregnant women across the three trimesters of pregnancy. After the tainted food report, the concentrations of urine PAE metabolite were significantly decreased, especially those of DEHP metabolites. Based on different reference limit values, the percentages of pregnant women whose HQ_DEHP value exceeded the limit ranged from 0.53% to 8.93%. Despite this low frequency, the higher ΣPAE exposure during the second trimester may significantly increase the risk of relatively low birth height compared to the lower exposure group (β=-0.63 (-1.20 to -0.06)). Our results support the hypothesis that exposure to relatively high concentrations of DEHP in pregnant Taiwanese women may have an adverse effect on birth outcomes. The percentage of subjects whose exposure level exceeded the exposure limit was low; however, high PAEs exposure appears to be significantly associated with birth outcomes. Therefore, we suggest that reference dose for PAEs should be revised.

Associations between urinary total arsenic levels, fetal development, and neonatal birth outcomes: A cohort study in Taiwan

BACKGROUND

Arsenic exposure is a global health concern. Several studies have focused on chronic arsenic exposure in adults; however, limited data are available regarding the potential adverse effects of prenatal exposure on fetuses and neonates.

OBJECTIVES

To assess which time point maternal arsenic exposure may influence the fetus during pregnancy and birth outcomes.

METHODS

In this study, total arsenic concentrations were analyzed in urine samples collected from 130 women with singleton pregnancies (22-45years old) in Taiwan from March to December of 2010. All fetal biometric measurements in each trimester period and birth outcomes at delivery were obtained. We applied a generalized estimating equation model and multivariate regression models to evaluate the associations between maternal urinary total arsenic (UtAs) exposure during pregnancy, fetal biometric measurements, and neonatal birth outcomes.

RESULTS

We observed statistically significant correlations between maternal UtAs levels and the fetal biparietal diameter over all three trimesters (β=-1.046mm, p<0.05). Multiple regression analyses showed a negative association between maternal UtAs levels and chest circumference in the first trimester (β=-0.721cm, p<0.05), and second-trimester UtAs exposure was associated with decreases in birth weight (β=-173.26g, p<0.01), head circumference (β=-0.611cm, p<0.05), and chest circumference (β=-0.654cm, p<0.05). Dose-response relationships were also observed for maternal UtAs exposure and birth outcomes.

CONCLUSIONS

We identified a negative relationship between maternal UtAs levels during pregnancy, fetal development, and neonatal birth outcomes. These findings should be confirmed in future studies with large sample sizes.

Concurrent exposures to nonylphenol, bisphenol A, phthalates, and organophosphate pesticides on birth outcomes: A cohort study in Taipei, Taiwan

Prenatal exposure to phenols, phthalates (PAEs), and organophosphate (OP) pesticides may increase the risk of abnormal birth outcomes. However, many previous studies have examined exposure to a limited number of chemical classes or exposure profiles limited to a specific stage of pregnancy. This study aims to characterize the concurrent exposure scenario throughout pregnancy by simultaneously monitoring internal doses of several endocrine-disrupting compounds (EDCs), including 2 phenols (nonylphenol (NP) and bisphenol A (BPA)), 9 PAEs, and 6 OP pesticide metabolites and to assess the relationships between concurrent exposure to EDCs and infant birth weight, length, and head and chest circumference. One hundred and sixty two women provided three spot urine samples at approximately 11 and 26weeks gestation and at delivery. We applied multivariable linear regression and ridge regression models to estimate the effects of separate and correlated exposures. Multivariable linear regression models revealed that women with short birth-length infants had significantly higher urinary second-trimester NP levels (50th percentile, 5.03μg/g creatinine) (β=-0.47cm; 95% CI=-0.93 to -0.01). Similarly significant relationships were observed between second-trimester mono-methyl phthalate (MMP) exposure and short birth length, second-trimester ΣPAEs and short birth length, second-trimester ΣPAEs exposure and reduced head and chest circumference, second-trimester diethylphosphate (DEP) exposure and reduced birth weight and length, and second-trimester ΣDEPs exposure and short birth length. Women with urinary BPA above the 75th percentile or ΣPAEs levels above the 50th percentile in the third trimester had infants with significantly reduced head circumference. These observations suggest that the second trimester may be the critical stage of susceptibility for fetal development. In ridge regression models, for which women with fewer measures for exposure to NP, BPA, MMP, ΣPAEs, DEP and ΣDEPs simultaneously were available, no relationships were found with infant size at birth. Additional studies with larger sample sizes are warranted.

Urinary Levels of 4-Nonylphenol and 4-t-Octylphenol in a Representative Sample of the Korean Adult Population

4-Nonylphenol (4-NP) and 4-t-octylphenol (4-t-OP) are xenoestrogen compounds to which humans are exposed via contaminated food, water, and air. This study assessed the body burden of 4-NP and 4-t-OP in Koreans aged 18-69 years using data from the Korean National Human Biomonitoring Survey conducted in 2009. Based on data from 1865 representative Koreans, 83.2% and 91.8% had urinary 4-NP and 4-t-OP concentrations >0.05 ng/mL (limit of detection). Of the Korean adult population, the geometric mean urinary concentrations of 4-NP and 4-t-OP were 3.70 ng/mL (95% confidence interval (CI) = 3.20-4.27) and 0.60 ng/mL (95% CI = 0.55-0.66), respectively. Urine 4-NP concentrations were significantly associated with place of residence and smoking status, whereas urine 4-t-OP concentrations were not correlated with any of the demographic factors. These findings suggest that most Koreans have detectable levels of 4-NP and 4-t-OP in their urine and that the body burden of 4-NP, but not 4-t-OP, varies according to some demographic factors.

Prenatal Nonylphenol and Bisphenol A Exposures and Inflammation Are Determinants of Oxidative/Nitrative Stress: A Taiwanese Cohort Study

Prenatal exposure to nonylphenol (NP) and/or bisphenol A (BPA) has been reported to be associated with adverse birth outcomes; however, the underlying mechanisms remain unclear. The primary mechanism is endocrine disruption of the binding affinity for the estrogen receptor, but oxidative stress and inflammation might also play a contributory role. We aimed to investigate urinary NP and BPA levels in relation to biomarkers of oxidative/nitrative stress and inflammation and to explore whether changes in oxidative/nitrative stress are a function of prenatal exposure to NP/BPA and inflammation in 241 mother-fetus pairs. Third-trimester urinary biomarkers of oxidative/nitrative stress were simultaneously measured, including products of oxidatively and nitratively damaged DNA (8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-nitroguanine (8-NO₂Gua)) as well as products of lipid peroxidation (8-iso-prostaglandin F_2α (8-isoPF_2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)). The antioxidant glutathione peroxidase (GPx) and inflammation biomarkers, including C-reactive protein (CRP) and a panel of cytokines (interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)), were analyzed in maternal and umbilical cord plasma samples. In adjusted models, we observed significant positive associations between NP exposure and 8-OHdG and 8-NO₂Gua levels, between BPA and 8-isoPF_2α levels, and between maternal CRP levels and HNE-MA levels. Additionally, BPA and TNF-α levels in cord blood were inversely associated with maternal and GPx levels in cord blood as well as maternal TNF-α levels were inversely associated with maternal GPx levels. These results support a role for exposure to NP and BPA and possibly inflammation in increasing oxidative/nitrative stress and decreasing antioxidant activity during pregnancy.

Exposure to endocrine disruptors during adulthood: consequences for female fertility

Endocrine disrupting chemicals are ubiquitous chemicals that exhibit endocrine disrupting properties in both humans and animals. Female reproduction is an important process, which is regulated by hormones and is susceptible to the effects of exposure to endocrine disrupting chemicals. Disruptions in female reproductive functions by endocrine disrupting chemicals may result in subfertility, infertility, improper hormone production, estrous and menstrual cycle abnormalities, anovulation, and early reproductive senescence. This review summarizes the effects of a variety of synthetic endocrine disrupting chemicals on fertility during adult life. The chemicals covered in this review are pesticides (organochlorines, organophosphates, carbamates, pyrethroids, and triazines), heavy metals (arsenic, lead, and mercury), diethylstilbesterol, plasticizer alternatives (di-(2-ethylhexyl) phthalate and bisphenol A alternatives), 2,3,7,8-tetrachlorodibenzo-p-dioxin, nonylphenol, polychlorinated biphenyls, triclosan, and parabens. This review focuses on the hypothalamus, pituitary, ovary, and uterus because together they regulate normal female fertility and the onset of reproductive senescence. The literature shows that several endocrine disrupting chemicals have endocrine disrupting abilities in females during adult life, causing fertility abnormalities in both humans and animals.

Detection of phenolic endocrine disrupting chemicals (EDCs) from maternal blood plasma and amniotic fluid in Indian population

There is a widespread exposure of general population, including pregnant women and developing fetuses, to the endocrine disrupting chemicals (EDCs). These chemicals have been reported to be present in urine, blood serum, breast milk and amniotic fluid. We aimed to investigate the association between the maternal exposure and in utero fetal exposure levels of these chemicals to study their transfer from maternal to fetal unit indicating prenatal exposure. Samples of maternal blood and amniotic fluid were collected as set from 53 pregnant women at full term. Nine phenolic EDCs, methyl paraben (MP; 20.92ng/mL and 18.92ng/mL), ethyl paraben (EP; 1.97ng/ mL and 1.89ng/mL), propyl paraben (PP; 19.22ng/mL and 18.82ng/mL), butyl paraben (BP; 1.11ng/mL and 1.37ng/mL), p-hydroxybenzoic acid (PHBA; 29.99ng/mL and 26.15ng/mL), bisphenol A (BPA; 7.43ng/mL and 7.75ng/mL), triclosan (TCS; 7.17ng/mL and 7.04ng/mL), octyl phenol (OP; 5.46ng/mL and 5.72ng/mL) and nonyl phenol (NP; 9.38ng/mL and 8.44ng/mL), were simultaneously detected in samples of maternal blood plasma and amniotic fluid respectively using Gas Chromatography-Mass Spectrometry (GC-MS). Highest positive correlation was found for total concentration of 4-nonyl phenol, NP (r=0.575, p<0.001), whereas the lowest positive correlation was found for free form of bisphenol A, BPA (r=0.343, p<0.05), when compared between the two matrices. Our results suggest that maternal exposure to several EDCs is positively associated with in utero exposure to the developing fetus. Future studies should focus on collection of amniotic fluid at different trimesters and the corresponding maternal samples to better characterize the pharmacokinetics and the associated disease etiologies of these EDCs during fetal development.

Attention Deficit/Hyperactivity Disorder and Urinary Nonylphenol Levels: A Case-Control Study in Taiwanese Children

Objective

Nonylphenol (NP) belongs to the family of endocrine disruptors, and it is widely used in industrial applications and is ubiquitous in daily foods. Animal studies have suggested that NP exposure might promote motor hyperactivity, likely by causing deficits in dopaminergic neurons. However, research assessing NP exposure and epidemiology studies on human populations are limited. The aim of this study was to explore the association between child NP exposure and ADHD while considering particular covariants, such as lead levels and dopamine-related gene variations.

Methods

A case-control study was conducted on patients with clinically diagnosed ADHD; the Swanson, Nolan and Pelham, Fourth Revision (SNAP-IV) questionnaire was used to identify normal controls aged 4–15 years. Participants were examined for urinary NP concentrations, blood lead levels, and select single-nucleotide polymorphisms of two dopamine-related genes (D4 dopamine receptor, DRD4, and dopamine transporter, DAT1). Socio-demographic variables, maternal lifestyle factors during pregnancy and family medical history were obtained using a questionnaire.

Results

A total of 97 children with doctor-diagnosed ADHD and 110 normal controls were enrolled. The blood lead levels in both groups were similar (1.57±0.73 vs. 1.73±0.77 μg/dL, p = 0.15). No significant difference in urinary NP concentration was found between the children with ADHD and the control subjects (4.52±3.22 μg/g cr. vs. 4.64±2.95 μg/g cr., p = 0.43). ADHD was significantly more prevalent among males in this study (male to female ratio: 5:1 for the ADHD group and 1.3:1 for the control group, p<0.01). The analysis was repeated after excluding the females, but this had no effect on the association between NP and ADHD. The regression model, including or excluding females, indicated no increased odds of having ADHD in the context of NP exposure after adjusting for covariants.

Conclusion

This study indicated that NP exposure might not promote ADHD in children, even though children in Taiwan had relatively high levels of NP compared to those reported previously and those in developed nations.

Prenatal nonylphenol exposure, oxidative and nitrative stress, and birth outcomes: A cohort study in Taiwan

Data concerning the effects of prenatal exposures to nonylphenol (NP) and oxidative stress on neonatal birth outcomes from human studies are limited. A total of 146 pregnant women were studied (1) to investigate the association between prenatal NP exposure and maternal oxidative/nitrative stress biomarkers of DNA damage (8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO2Gua)) and lipid peroxidation (8-iso-prostaglandin F2α (8-isoPF2α), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)) and (2) to explore the associations among oxidative stress biomarkers, NP exposure, and neonatal birth outcomes, including gestational age, birth weight, length, Ponderal index, and head and chest circumferences. NP significantly increased the 8-OHdG and 8-NO2Gua levels. All infants born to mothers with urinary 8-OHdG levels above the median exhibited a significantly shorter gestational duration (Badjusted = -4.72 days; 95% CI: -8.08 to -1.36 days). No clear association was found between NP levels and birth outcomes. Prenatal 8-OHdG levels might be a novel biomarker for monitoring fetal health related to NP exposure.

The critical fetal stage for maternal manganese exposure

Prenatal exposure and the health effects of that exposure have been intensively studied for a variety of environmental pollutants and trace elements. However, few studies have compared susceptibilities among the three trimesters of gestation. Manganese (Mn) is a naturally occurring and abundant trace element in the environment. Although the effects of Mn on animals are well documented, knowledge of the effects of Mn exposure on pregnant women and fetuses remains limited. A longitudinal study was conducted by collecting blood samples during all three trimesters, and Mn exposure was completely characterized during gestation. The aims of this study were to examine the effects of maternal Mn exposure on neonatal birth outcomes and to explore the critical stage of these effects. In total, 38, 76 and 76 samples were obtained from singleton pregnant women in their first, second and third trimesters, respectively. The cohort of pregnant women was selected at a medical center in northern Taiwan. Erythrocyte samples were collected during the first, second and third trimesters of gestation. Erythrocyte Mn concentrations were measured by inductively coupled plasma mass spectrometry. Neonatal birth outcomes were evaluated immediately after delivery. A multivariate regression model was used to determine the associations between maternal Mn levels in erythrocytes in each trimester and neonatal birth outcomes. The geometric mean concentrations of Mn were 2.93 μg/dL, 3.96 μg/dL and 4.41 μg/dL in the first, second and third trimesters, respectively. After adjusting for potential confounders, a consistently negative association was found between maternal Mn levels throughout the three trimesters and birth outcomes. Log-transformed Mn levels in maternal erythrocytes in the second trimester were significantly associated with neonatal birth weight, head and chest circumferences, respectively (β=-556.98 g, p=0.038; β=-1.87 cm, p=0.045; β=-2.74 cm, p=0.024). Despite the limited sample size in the first trimester, negative effects of maternal Mn levels on birth weight (β=-1108.95 g, p<0.01) and chest circumference (β=-4.40 cm, p=0.019) were also observed.

Nonylphenol in pregnant women and their matching fetuses: placental transfer and potential risks of infants

As the predominant environmental biodegradation product of nonylphenol (NP) ethoxylates and with proven estrogenic effects, NP is formed during the alkylation process of phenols. The purposes of this study were (1) to examine maternal and prenatal exposure to NP in Taiwan, (2) to determine the level of placental protection against NP exposure as well as the level of NP in breast milk, and (3) to assess the potential risk for breastfed newborns exposed to NP through the milk. Thirty pairs of maternal and fetal blood samples, placenta, and breast milk during the 1st and the 3rd months of lactation were collected. External NP exposures of these specimens were then analyzed by using high-performance liquid chromatography coupling with fluorescence detection. Next, the socio-demographics, lifestyle, delivery method, dietary and work history were collected using a questionnaire. In addition, the daily intake of NP from consuming breast milk in the 1st and 3rd months for newborns was studied through deterministic and probabilistic risk assessment methods. The geometric means and geometric standard deviation of NP levels in maternal blood, fetal cord blood, placenta, and breast milk in the 1st and 3rd months were 14.6 (1.7) ng/ml, 18.8 (1.8) ng/ml, 19.8 (1.9) ng/g, 23.5 (3.2) ng/ml, and 57.3 (1.4) ng/ml, respectively. The probabilistic percentiles (50th, 75th, and 95th) of daily intake NP in breast milk were 4.33, 7.79, and 18.39 μg/kg-bw/day in the 1st month, respectively, and were 8.11, 10.78, 16.08 μg/kg-bw/day in the 3rd month, respectively. The probabilistic distributions (5th, 25th, and 50th) of risk for infants aged 1 month old were 0.27, 0.64, and 1.15, respectively, and that for infants aged 3 month old were 0.31, 0.46, and 0.62, respectively. Through repeated exposure from the dietary intake of expectant mothers, fetuses could encounter a high NP exposure level due to transplacental absorption, partitioning between the maternal and fetal compartments. Daily NP intake via breast milk in three month-old babies exceeded the tolerable daily intake (TDI) of 5 µg/kg bw/day indicated a potential risk for Taiwan infants.

The association between nonylphenols and sexual hormones levels among pregnant women: a cohort study in Taiwan

Background

Nonylphenol (NP) has been proven as an endocrine disrupter and had the ability to interfere with the endocrine system. Though the health effects of NP on pregnant women and their fetuses are sustained, these negative associations related to the mechanisms of regulation for estrogen during pregnancy need to be further clarified. The objective of this study is to explore the association between maternal NP and hormonal levels, such as estradiol, testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH), and progesterone.

Methods

A pregnant women cohort was established in North Taiwan between March and December 2010. Maternal urine and blood samples from the first, second, and third trimesters of gestation were collected. Urinary NP concentration was measured by high-performance liquid chromatography coupled with fluorescent detection. A mixed-effects model using a generalised estimating equation (GEE) was applied to assess the associations between maternal NP concentration and plasma hormones throughout the three trimesters.

Results

In total, 162 singleton pregnant women completed this study through delivery. The geometric mean of creatinine-adjusted urinary NP concentrations were 4.27, 4.21, and 4.10 µg/g cre. in the first, second, and third trimesters respectively. A natural log-transformation of urinary NP concentrations were significantly associated with LH in the GEE model (β = −0.23 mIU/ml, p<0.01).

Conclusion

This perspective cohort study demonstrates that negative association occurs between maternal NP exposure and plasma LH levels. The estrogen-mimic effect of NP might influence the negative feedback on LH during pregnancy.