Season-dependent concentrations of urinary phthalate metabolites among Chinese pregnant women: Repeated measures analysis

Trimester-specific effect of maternal co-exposure to organophosphate esters and phthalates on preschooler cognitive development: The moderating role of gestational vitamin D status

Organophosphate esters (OPEs) and phthalate acid esters (PAEs) are prevalent endocrine-disrupting chemicals (EDCs). Humans are often exposed to OPEs and PAEs simultaneously through multiple routes. Given that fetal stage is a critical period for neurodevelopment, it is necessary to know whether gestational co-exposure to OPEs and PAEs affects fetal neurodevelopment. However, accessible epidemiological studies are limited. The present study included 2, 120 pregnant women from the Ma'anshan Birth Cohort (MABC) study. The concentrations of tris (2-chloroethyl) phosphate (TCEP), 6 OPE metabolites and 7 PAE metabolites were measured in the first, second and third trimester using ultra-performance liquid chromatography-tandem mass spectrometry (LC-MS). Cognitive development of preschooler was assessed based on the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition (WPPSI-IV) of the Chinese version. Generalized estimating equations (GEEs), restricted cubic spline (RCS) and generalized additive models (GAMs) were employed to explore the associations between individual OPE exposure and preschooler cognitive development. The quantile-based g-computation (QGC) method was used to estimate the joint effect of PAEs and OPEs exposure on cognitive development. GEEs revealed significant adverse associations between diphenyl phosphate (DPHP) (β: -0.58, 95% CI: -1.14, -0.01), bis (2-butoxyethyl) phosphate(BBOEP) (β: -0.44, 95% CI: -0.85, -0.02), bis(1-chloro-2-propyl) phosphate (BCIPP) (β: -0.81, 95%CI: -1.43, -0.20) and full-scale intelligence quotient (FSIQ) in the first trimester; additionally, TCEP and bis(2-ethylhexyl) phosphate (BEHP) in the second trimester, as well as DPHP in the third trimester, were negatively associated with cognitive development. Through the QGC analyses, mixture exposure in the first trimester was negatively associated with FSIQ scores (β: -1.70, 95% CI: -3.06, -0.34), mono-butyl phthalate (MBP), BCIPP, and DPHP might be the dominant contributors after controlling for other OPEs and PAEs congeners. Additionally, the effect of OPEs and PAEs mixture on cognitive development might be driven by vitamin D deficiency.

Gender associations between phthalate exposure and biomarkers of oxidative stress: A prospective cohort study

Previous epidemiologic research has shown that phthalate exposure in pregnant women is related to adverse birth outcomes in a sex-specific manner. However, the biological mechanism of phthalate exposure that causes these birth outcomes remains poorly defined. In this research, we investigated the association between phthalate exposure and placental oxidative stress in a large population-based cohort study, aiming to initially explore the relationship between phthalate exposure and gene expression in placental oxidative stress in a sex-specific manner. Quantitative PCR was performed to measure the expression of placental inflammatory mRNAs (HO-1, HIF1α, and GRP78) in 2469 placentae. The multiple linear regression models were used to investigate the associations between mRNA and urinary phthalate monoesters. Phthalate metabolites monomethyl phthalate (MMP) and mono-n-butyl phthalate (MBP) were positively correlated with higher HIF1α expression in placentae of male fetuses (p < .05). Mono-benzyl phthalate (MBzP) increased the expression of HO-1, HIF1α, and GRP78 in placentae of male fetuses, and mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) up-regulated the expression of HIF1α and GRP78. Additionally, mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) was negatively correlated with HO-1, HIF1α, and GRP78 in placentae of female fetuses. Maternal phthalate exposure was associated with oxidative stress variations in placental tissues. The associations were closer in the placentas of male fetuses than in that of female ones. The placenta oxidative stress is worth further investigation as a potential mediator of maternal exposure-induced disease risk in children.

No role of the third-trimester inflammatory factors in the association of gestational diabetes mellitus with postpartum cardiometabolic indicators

BACKGROUND

The influence of gestational diabetes mellitus (GDM) on postpartum cardiometabolic indicators is primarily restricted to glucose and lipid metabolism, however the indicators for liver and kidney function have been rarely explored, and the role of the third-trimester inflammatory factors in these associations has never been investigated.

METHODS

Based on the Ma'anshan birth cohort (MABC), women with or without GDM history were selected and invited to participate in a 6-year postpartum follow-up. The fasting blood samples were collected to measure 16 comprehensive metabolic indicators during a 6-year postpartum follow-up: fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), triglycerides (TG), total cholesterol (TC), uric acid (UA), blood urea nitrogen (BUN), serum creatinine (SCR), etc. Seven inflammatory factors, including TNF-α, IFN-γ, IL-1β, IL-6, IL-10, IL-12p70, and IL-17 A, were measured with serum samples collected during the third trimester of pregnancy. Linear regression models were used to analyze the associations between GDM and 6-year postpartum metabolic indicators, GDM and third-trimester inflammatory factors, and the third-trimester inflammatory factors and 6-year postpartum metabolic indicators. Mediating and moderating effect analyses were further performed to explore if the third-trimester inflammatory factors mediate or modify the association between GDM and postpartum cardiometabolic indicators.

RESULTS

From July 2021 to August 2022, 307 participants have been followed up, with 99 women with a prior GDM history. Compared with those without GDM, individuals with a prior history of GDM had significantly elevated levels of FPG (β = 0.40, 95% CI: 0.18 to 0.62, PFDR < 0.001), HbA1c (β = 0.22, 95% CI: 0.09 to 0.34, PFDR = 0.009), TyG (β = 0.22, 95% CI: 0.07 to 0.37, PFDR = 0.024) at 6 years postpartum, and the association between GDM and SCR (β = 2.43, 95% CI: 0.02 to 4.85, PFDR = 0.144) reached nominal significance level. GDM history was associated with a decreased level of third-trimester IL-17 A (β = -0.58, 95% CI: -0.99 to -0.18, PFDR = 0.035). No significant association between third-trimester inflammatory factors and 6-year postpartum metabolic indicators was observed. And no mediating or moderating effect of third-trimester inflammatory factors was observed in those associations.

CONCLUSION

A prior history of GDM was significantly associated with elevated FPG, HbA1c, and TyG in women at 6 years postpartum, whereas third-trimester inflammatory factors had no role in mediating or moderating these associations.

Phthalate exposure aggravates periodontitis by activating NFκB pathway

BACKGROUND

Phthalates are widely used plasticizers, which were identified as risk factors in the development of many human diseases. However, the effects of phthalates in the periodontitis are unknown. We aimed to investigated the relationship of periodontitis and phthalate exposure as well as the underlying mechanisms.

MATERIALS AND METHODS

Univariate and multivariate logistic regressions were employed to evaluate the association between phthalate metabolites and periodontitis. The generalized additive model and piecewise logistic regression were conducted to investigate the dose-response relationship. Cell and animal models were used to explore the role and mechanism of DEHP in the development of periodontitis. Transcriptome sequencing, bioinformatics analysis, western blot, immunofluorescence and mice model of periodontitis were also employed.

RESULTS

MEHP (OR 1.14, 95% CI 1.05-1.24), MCPP (OR 1.08, 95% CI 1.00-1.17), MEHHP (OR 1.18, 95% CI 1.08-1.29), MEOHP (OR 1.18, 95% CI 1.07-1.29), MiBP (OR 1.15, 95% CI 1.04-1.28), and MECPP (OR 1.20, 95% CI 1.09-1.32) were independent risk factors. And MEHHP, the metabolite of DEHP, showed the relative most important effects on periodontitis with the highest weight (0.34) among all risk factors assessed. And the increase of inflammation and the activation of NFκB pathway in the periodontitis model mice and cells were observed.

CONCLUSION

Exposure to multiple phthalates was positively associated with periodontitis in US adults between 30 and 80 years old. And DEHP aggravated inflammation in periodontitis by activating NFκB pathway.

Association of maternal phthalates exposure and metabolic gene polymorphisms with congenital heart diseases: a multicenter case-control study

BACKGROUND

The majority of congenital heart diseases (CHDs) are thought to result from the interactions of genetics and the environment factors. This study aimed to assess the association of maternal non-occupational phthalates exposure, metabolic gene polymorphisms and their interactions with risk of CHDs in offspring.

METHODS

A multicenter case-control study of 245 mothers with CHDs infants and 268 control mothers of health infant was conducted from six hospitals. Maternal urinary concentrations of eight phthalate metabolites were measured by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Twenty single nucleotide polymorphisms (SNPs) in cytochrome P450 family 2 subfamily C member 9 (CYP2C9) and 19 (CYP2C19), uridine diphosphate (UDP) glucuronosyl transferase family 1 member A7 (UGT1A7), family 2 member B7 (UGT2B7) and B15(UGT2B15) genes were genotyped. The multivariate logistic regressions were used to estimate the association between maternal phthalates exposure or gene polymorphisms and risk of CHDs. Generalized multifactor dimensionality reduction (GMDR) was used to analyze the gene-gene and gene-phthalates exposure interactions.

RESULTS

There was no significant difference in phthalate metabolites concentrations between the cases and controls. No significant positive associations were observed between maternal exposure to phthalates and CHDs. The SNPs of UGT1A7 gene at rs4124874 (under three models, log-additive: aOR = 1.74, 95% CI:1.28-2.37; dominant: aOR = 1.86, 95% CI:1.25-2.78; recessive: aOR = 2.50, 95% CI: 1.26-4.94) and rs887829 (under the recessive model: aOR = 13.66, 95% CI: 1.54-121) were significantly associated with an increased risk of CHDs. Furthermore, the associations between rs4124874 (under log-additive and dominant models) of UGT1A7 were statistically significant after the false discovery rate correction. No significant gene-gene or gene-phthalate metabolites interactions were observed.

CONCLUSIONS

The polymorphisms of maternal UGT1A7 gene at rs4124874 and rs887829 were significantly associated with an increased risk of CHDs. More large-scale studies or prospective study designs are needed to confirm or refute our findings in the future.

Prenatal phthalate exposure and neurodevelopmental differences in twins at 2 years of age

BACKGROUND

Previous studies of singletons evaluating prenatal phthalate exposure and early neurodevelopment reported mixed results and the associations could be biased by parental, obstetrical, and genetic factors.

METHODS

A co-twin control design was employed to test whether prenatal phthalate exposure was associated with children's neurocognitive development. We collected information from 97 mother-twin pairs enrolled in the Wuhan Twin Birth Cohort between March 2016 and October 2018. Fourteen phthalate metabolites were measured in maternal urine collected at each trimester. Neurodevelopmental differences in twins at the age of two were examined as the outcome of interest. Multiple informant model was used to examine the covariate-adjusted associations of prenatal phthalate exposure with mental development index (MDI) and psychomotor development index (PDI) scores assessed at 2 years of age based on Bayley Scales of Infant Development (Second Edition). This model also helps to identify the exposure window of susceptibility.

RESULTS

Maternal urinary levels of mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 1.91, 95% CI: 0.43, 3.39), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (β = 1.56, 95% CI: 0.33, 2.79), and the sum of di-(2-ethylhexyl) phthalate metabolites (∑DEHP) (β = 1.85, 95% CI: 0.39, 3.31) during the first trimester showed the strongest and significant positive associations with intra-twin MDI difference. When stratified with twin chorionicity, the positive associations of monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), individual DEHP metabolites, and ∑DEHP exposure during pregnancy with intra-twin neurodevelopmental differences were more significant in monochorionic diamniotic (MCDA) twins than those in dichorionic diamniotic (DCDA) twins.

CONCLUSIONS

Neurodevelopmental differences in MCDA twins were strongly associated with prenatal phthalate exposure. Our findings warrant further confirmation in longitudinal studies with larger sample sizes.

Predictors of Phthalate Metabolites Exposure among Healthy Pregnant Women in the United States, 2010-2015

Phthalate use and the concentrations of their metabolites in humans vary by geographic region, race, ethnicity, sex, product use and other factors. Exposure during pregnancy may be associated with detrimental reproductive and developmental outcomes. No studies have evaluated the predictors of exposure to a wide range of phthalate metabolites in a large, diverse population. We examined the determinants of phthalate metabolites in a cohort of racially/ethnically diverse nulliparous pregnant women. We report on urinary metabolites of nine parent phthalates or replacement compounds-Butyl benzyl phthalate (BBzP), Diisobutyl phthalate (DiBP), Diethyl phthalate (DEP), Diisononyl phthalate (DiNP), D-n-octyl phthalate (DnOP), Di-2-ethylhexyl terephthalate (DEHTP), Di-n/i-butyl phthalate (DnBP), Di-isononyl phthalate (DiNP) and Di-(2-ethylhexyl) phthalate (DEHP) from urine collected up to three times from 953 women enrolled in the Nulliparous Mothers To Be Study. Phthalate metabolites were adjusted for specific gravity. Generalized estimating equations (GEEs) were used to identify the predictors of each metabolite. Overall predictors include age, race and ethnicity, education, BMI and clinical site of care. Women who were Non-Hispanic Black, Hispanic or Asian, obese or had lower levels of education had higher concentrations of selected metabolites. These findings indicate exposure patterns that require policies to reduce exposure in specific subgroups.

Co-Exposure of Polycyclic Aromatic Hydrocarbons and Phthalates with Blood Cell-Based Inflammation in Early Pregnant Women

Cumulative evidence has demonstrated that exposure to polycyclic aromatic hydrocarbons (PAHs) or phthalates (PAEs) contributes to a variety of adverse health effects. However, the association of PAHs and PAEs co-exposure with blood cell-based inflammatory indicators during early pregnancy is still unclear. We aimed to investigate the single and mixed associations of exposure to PAHs and PAEs with blood cell-based inflammatory indicators among early pregnant women. A total of 318 early pregnant women were included in this study. General linear regressions were used to estimate the relationships of individual OH-PAHs and mPAEs with blood cell-based inflammatory indicators. The key pollutants were selected by an adapted least absolute shrinkage and selection operator (LASSO) penalized regression model and wasemployed to build the Bayesian kernel machine regression (BKMR) and quantile g-computation (Q-g) models, which can assess the joint association of OH-PAHs and mPAEs with blood cell-based inflammatory indicators. General linear regression indicated that each 1% increase in MOP was associated with a 4.92% (95% CI: 2.12%, 7.68%), 3.25% (95% CI: 0.50%, 6.18%), 5.87% (95% CI: 2.22%, 9.64%), and 6.50% (95% CI: 3.46%, 9.64%) increase in WBC, lymphocytes, neutrophils, and monocytes, respectively. BKMR and Q-g analysis showed that the mixture of OH-PAHs and mPAEs was linked with increased levels of white blood cells (WBC), neutrophils, monocytes, and lymphocytes, and MOP was identified as the dominant contributor. OH-PAHs and mPAEs co-exposure in early pregnancy was associated with elevated blood cell-based inflammatory indicators reactions. More attention should be paid to the inflammation induced by environmental pollution for perinatal women, especially early pregnant women.

Supporting legislative action: Urinary levels of phthalates and phenols among influencers in the 'Plastics in the spotlight' advocacy initiative

BACKGROUND

Society-wide initiatives to prevent human exposure to plastic residues include laws and policies. Such measures require citizens' support, which can be increased by honest advocacy and pedagogic projects. These efforts must have a scientific basis.

OBJECTIVE

To assist the 'Plastics in the spotlight' advocacy initiative raise awareness among the general public of the presence of plastic residues in the human body, and to increase citizens' support for legislation on plastic control in the European Union.

METHODS

Spot urine samples of 69 volunteers with cultural and political influence from Spain, Portugal, Latvia, Slovenia, Belgium, and Bulgaria were collected. Concentrations of 30 phthalate metabolites and phenols were determined through a high-performance liquid chromatography with tandem mass spectrometry and ultra-high-performance liquid chromatography with tandem mass spectrometry, respectively.

RESULTS

At least 18 compounds were detected in all urine samples. The maximum number of compounds detected per participant was 23, and the mean, 20.5. Phthalates were detected more frequently than phenols. Median concentrations were highest for monoethyl phthalate (41.6 ng/mL, adjusted for specific gravity), and maximum concentrations were highest for mono-iso-butyl phthalate (1345.1 ng/mL), oxybenzone (1915.1 ng/mL), and triclosan (949.6 ng/mL). Most reference values were not exceeded. Women had higher concentrations of the 14 phthalate metabolites and oxybenzone than men. Urinary concentrations were not correlated with age.

DISCUSSION

The study had three main limitations: method of subject selection (volunteers), small sample size, and limited data on determinants of exposure. Studies on volunteers do not pretend to be representative of the general population and are no substitute for biomonitoring studies in representative samples of the populations of interest. Studies as ours can only illustrate the existence and some aspects of the problem, and can raise awareness among citizens concerned by the evidence that the studies provide in a group of subjects who are humanly appealing.

CONCLUSIONS

The results illustrate that human exposure to phthalates and phenols is widespread. All countries appeared to be similarly exposed to these contaminants, with higher levels in females. Most concentrations did not exceed reference values. The effects of this study on the objectives of the 'Plastics in the spotlight' advocacy initiative deserve a specific analysis from policy science.

Associations of urinary phthalate metabolites with household environments among mothers and their preschool-age children

Phthalates have become a matter of public health concern due to their extensive use worldwide and negative health effects. The evaluation of potential sources of phthalate exposure is crucial to design prevention strategies, especially for vulnerable populations. This study included 528 mother-child pairs in the Taiwan Mother Infant Cohort Study who were followed up at ages 3-6 years between 2016 and 2020. Each mother was interviewed by using a structured questionnaire containing questions on demographic characteristics and household environment factors, such as the use of plastic food packaging, residential visible mold, insecticide sprays, and electric mosquito repellents. Eleven phthalate metabolites were analyzed in urine samples simultaneously collected from the mother-child pairs. The phthalate metabolite urinary concentrations were higher among the children than among their mothers, except those of mono-ethyl phthalate (MEP) and mono-2-ethylhexyl phthalate (MEHP). Multiple linear regression analyses showed that urine samples collected during the summer showed higher concentrations of phthalate metabolites than those collected during the winter. Family income levels had negative associations with the concentrations of MnBP and metabolites of di-2-ethylhexyl phthalate (DEHP) in children. The use of plastic food packaging was positively associated with mono-n-butyl phthalate (MnBP) and metabolites of DEHP in mothers. Residential visible mold or mold stains were significantly associated with higher MnBP and DEHP metabolite concentrations in children. The use of insecticide sprays was positively associated with MnBP concentrations in children. Significant associations between household environmental factors and phthalate exposure were mostly found in children, potentially indicating different exposure pathways between mothers and their children. Findings from this study provide additional information for the design of prevention strategies to protect the health of children and women.

The effect of phthalates exposure during pregnancy on asthma in infants aged 0 to 36 months: a birth cohort study

This cohort study sought to investigate the effects of phthalates exposure during pregnancy on offspring asthma and its association with placental stress and inflammatory factor mRNA expression levels. A total of 3474 pregnant women from the China Ma'anshan birth cohort participated in this study. Seven phthalate metabolites were detected in urine samples during pregnancy by solid phase extraction-high-performance liquid chromatography tandem mass spectrometry. Placenta stress and inflammation mRNA expression were assessed by real-time quantitative polymerase chain reaction (RT-qPCR). Early pregnancy may be the critical period when phthalates exposure increases the risk of asthma in infants and young children, and there is a certain gender difference in the risk of asthma in infants and young children. Moreover, through the placenta stress and inflammatory factor associated with infant asthma found anti-inflammatory factor of interleukin-10 (IL-10) mRNA expression will reduce the risk of 36-month-old male infant asthma. The expression of interleukin-4(IL-4) and macrophage (M2) biomarker cluster of differentiation 206(CD206) mRNA reduced the risk of asthma in 18-month-old female infants. Placental stress and inflammatory response were analyzed using mediating effects. Tumor necrosis factor-α (TNFα) showed a complete mediating effect between mono-benzyl phthalate (MBzP) exposure in early pregnancy and asthma in 12-month-old males, and IL-10 also showed a complete mediating effect between mono-n-butyl phthalate (MBP) exposure in early and late pregnancy and asthma in 36-month-old males. In summary, exposure to phthalates during pregnancy may contribute to the development of asthma in infants, which may be associated with placental stress and inflammation.

Exposure to phthalates and DiNCH among preschool children in Sweden: Urinary metabolite concentrations and predictors of exposure

Several plasticizing chemicals induce endocrine disrupting effects in humans, and the indoor environment is suggested to be a source of exposure. As children are particularly vulnerable to the effects from exposure to endocrine disrupting chemicals (EDCs), it is essential to monitor exposure to EDCs such as phthalates and non-phthalate plasticizers in indoor environments intended for use by children. The aim of this study was to assess everyday plasticizer exposure among preschool-aged children in Sweden by measuring urinary plasticizer metabolite concentrations. In addition, it was investigated whether the concentrations would be altered as a result of the children spending part of the day at preschool, in comparison with weekend exposure, when they may spend more time in home environments or engage in various weekend and leisure activities. For this purpose, fourteen metabolites from eight phthalates (di-ethylhexyl phthalate, DEHP; di-n-butyl phthalate, DnBP; di-isobutyl phthalate, DiBP; butyl-benzyl phthalate, BBzP; di-iso-nonyl phthalate, DiNP; di-propylheptyl phthalate, DPHP; di-iso-decyl phthalate, DiDP; and di-ethyl phthalate, DEP) and one non-phthalate plasticizer (di-isononyl cyclohexane 1,2-dicarboxylate, DiNCH) were measured in 206 urine samples collected at four occasions, i.e. twice during the winter and twice during the spring from 54 children (mean 5.1 years, SD 0.94) enrolled at eight preschools in Sweden. A detection frequency (DF) of 99.9% for the 14 metabolites indicates a widespread exposure to plasticizers among children in Sweden. Compared to previous Swedish and international studies performed during approximately the same time period, high urinary concentrations of monobenzyl phthalate (MBzP), a metabolite from the strictly regulated BBzP, were measured in this study (median 17 ng/mL). Overall, high urinary phthalate metabolite concentrations were observed in this study compared to the US CDC-NHANES from the same time period and similar age-group. Compared to European studies, however, similar concentrations were observed for most metabolites and the urinary concentrations from few participating children exceeded the human biomonitoring guidance values (HBM-GV) for children. After days with preschool attendance, lower urinary concentrations of metabolites originating from DEP and phthalates that are strictly regulated within the EU REACH legislation (DEHP, DnBP, and DiBP) and higher concentrations of metabolites originating from DiNP, DPHP, and DiDP, i.e. less or non-regulated phthalates were found compared the urinary concentrations of these metabolites in weekends. This may indicate that factors in the indoor environment itself are important for the extent of the plasticizer exposure. All the analyzed metabolites were measured in lower concentrations in urine collected from children attending preschools built or renovated after the year 2000, while no seasonal differences were observed in this study.

Occurrences and potential lipid-disrupting effects of phthalate metabolites in humpback dolphins from the South China Sea

Phthalate esters (PAEs) are ubiquitous environmental contaminants, arising growing public concern. Nevertheless, information on the exposure and risks of PAEs in wildlife remains limited. Here, we conducted the first investigation of the occurrences, spatiotemporal trends, and potential risks of twelve metabolites of PAEs (mPAEs) in 74 humpback dolphins from the northern South China Sea during 2005-2020. All twelve mPAEs (∑₁₂mPAEs: 9.6-810.7 ng g^-1 wet weight) were detected in the dolphin liver, and seven major mPAEs showed increasing trends during the study period, indicating high PAE contamination in the coastal environment of South China. Monoethylhexyl phthalate accounted for over half of the ∑₁₂mPAE concentrations. The accumulation of mPAEs in the dolphins was neither age-dependent nor sex-specific. Compared to parent PAEs, mPAEs generally induced higher agonistic effects on the dolphin peroxisome proliferator-activated receptor alpha/gamma (PPARA/G) as master regulators of lipid homeostasis. Although short-term in vitro assays revealed no significant activation of dolphin PPARA/G by tissue-relevant doses of mPAEs, long-term in vivo evidence (i.e., correlations between hepatic mPAEs and blubber fatty acids) suggested that chronic exposure to mPAEs might have impacted lipid metabolism in the dolphin. This study highlighted the potential health risks of PAE exposure on marine mammals.

Co-exposure to phenols and phthalates during pregnancy with the difference of body size in twins at one month old

Humans are simultaneously exposed to phenols and phthalates (PAEs). However, the mixture effect of phenols and PAEs on the body size of twins is lacking. From 2016 to 2018, we recruited 228 pregnant twins and collected up to three urine samples. A total of 8 PAE metabolites and 7 phenols were detected in urine by liquid chromatography-tandem mass spectrometry. Chemical individual and mixture effects were estimated. Multivariable linear regression results presented the percentage change in twins' growth differences at one month old with maternal PAE and phenol exposure. These chemicals were positively associated with weight differences during the entire trimester. Moreover, the quantile g-computed model showed that increased urinary concentrations of all chemicals by one quartile were associated with a 22.85% (95%CI: 11.21-35.72%), 22.60% (95%CI: 12.31-33.83%), and 24.05% (95%CI: 13.11-36.05%) larger weight difference within twins in each trimester, respectively. Increasing all PAE metabolites and phenols by one quantile across the entire trimester, weight differences increased by 26.61% (95% CI: 15.79%, 38.44%), and height differences increased by 15.84% (95%CI: 3.92%, 29.13%). Co-exposure to PAEs and phenols may primarily play a role in twins' growth.

Partition of phthalates among air, PM2 .5 , house dust and skin in residential indoor environments

As a group of typical endocrine disrupters, phthalates are simultaneously present in a variety of environmental media and enter human body through multiple exposure pathways. In this study, field monitoring data were used to characterize the skin-air (K_lg ), dust-air (K_d ), and PM_2.5 -air (K_p ) partition coefficients of DiBP, DnBP, and DEHP. The median values of log(K_lg ) in the summer and winter were 7.654 and 7.932, 7.265 and 7.902, 9.419 and 9.015 for DiBP, DnBP, and DEHP, respectively, and K_lg was significantly higher in the winter. The median K_d (m³ /mg) in the summer (0.036-0.151 for DiBP, 0.021-0.036 for DnBP and 1.479-4.069 for DEHP) were significantly higher than the counterparts in the winter (0.027-0.065 for DiBP, 0.022-0.245 for DnBP, and 0.140-3.250 for DEHP). In addition, K_d was associated with material of surface and residence time of dust. The K_p values (m³ /μg) of DiBP, DnBP, and DEHP in the summer (0.053, 0.015, and 0.021) were also significantly higher than the counterparts in the winter (0.011, 0.004, and 0.025). The partition of phthalates was influenced by built environment, such as temperature, humidity, ventilation, indoor chemistry, smoking, and building age. Except K_lg , there was substantial discrepancy between the estimates of K with empirical equations and the values of K based on field monitoring data in our study.

Relationship of individual and mixed prenatal phthalate exposure with placental structure and efficiency in the prospective Ma'anshan Birth Cohort Study

BACKGROUND

Few studies have investigated the associations between prenatal phthalate exposure and placental structure and function with inconsistent conclusions.

METHODS

Nested on the Ma'anshan Birth Cohort study, 2723 women provided spot urine samples during the first, second and third trimesters of pregnancy to analyze six phthalate metabolites. The outcomes of interest were placental weight, efficiency (birth weight/placental weight), chorionic disc area and disc eccentricity. The relationships of prenatal exposure to a single phthalate with placental measures were analyzed. The associations between prenatal phthalate mixture exposure and placental measures were also evaluated.

RESULTS

Most phthalate metabolites were significantly associated with placental weight, efficiency and chorionic disc area during the whole gestation and in each trimester of pregnancy, with different directions of relationships. Sensitivity analyses revealed similar findings, indicating the robustness of the statistical results. Furthermore, inverted U-shaped nonlinear relationships of prenatal exposure to some phthalate metabolites with placental weight, efficiency and chorionic plate area were observed. However, quantile g-computation mixture models did not reveal any association between maternal combined exposure to the total phthalate metabolites and placental measures.

CONCLUSIONS

Maternal exposure to most phthalates and their metabolites was associated with placental weight, efficiency and chorionic plate area in both a linear manner and an inverted U-shaped nonlinear manner. However, the mixture of multiple phthalate metabolites was not observed to be associated with any placental measure.

Urinary tetracycline antibiotics exposure during pregnancy and maternal thyroid hormone parameters: A repeated measures study

BACKGROUND

Studies on potential maternal thyrotoxicity related to tetracycline antibiotics exposure during pregnancy are lacking. Based on a large prospective cohort study, this study aimed to examine the associations between tetracycline antibiotics exposure in maternal urine and maternal thyroid hormone parameters.

METHODS

Based on the Ma'anshan Birth Cohort study, urine and serum samples of 2969 pregnant women were collected in the first, second and third trimesters. Tetracycline antibiotics, including oxytetracycline, chlorotetracycline, tetracycline and doxycycline in urine samples, as well as free thyroxine (FT4), thyroid stimulating hormone (TSH), total triiodothyronine (TT3) and total thyroxine (TT4) levels in serum samples, were measured. Linear mixed models and multivariate linear regression models were employed to examine associations between tetracycline antibiotics exposure during pregnancy and maternal thyroid hormone parameters.

RESULTS

The detection rates of four individual tetracycline antibiotics and all antibiotics (sum of four individual tetracycline antibiotics) in the three trimesters were 5.0%-52.3%, and the 95th percentile concentration ranged from 0.11 to 4.84 ng/mL. After adjusting for potential confounding factors, the repeated measures analyses indicated that pregnant women exposed to doxycycline and all antibiotics during the entire pregnancy were negatively associated with serum FT4 and TT4 levels but positively associated with serum TSH and TT3 levels. Trimester-stratified analyses found that doxycycline and all antibiotics exposure during the first trimester were negatively associated with serum FT4 and TT4 levels, while doxycycline was positively associated with TSH levels. In the third trimester, a significant association was only found between all antibiotics and TSH levels.

CONCLUSIONS

Our results suggest that exposure of pregnant women to tetracycline antibiotics is associated with maternal thyroid hormone parameters, and the first trimester might be the most critical window. More studies are needed to substantiate our findings and determine the underlying biological mechanisms.

Determinants of phthalate exposures in pregnant women in New York City

Previous studies have provided data on determinants of phthalates in pregnant women, but results were disparate across regions. We aimed to identify the food groups and demographic factors that predict phthalate exposure in an urban contemporary pregnancy cohort in the US. The study included 450 pregnant women from the New York University Children's Health and Environment Study in New York City. Urinary concentrations of 22 phthalate metabolites, including metabolites of di-2-ethylhexylphthalate (DEHP), were determined at three time points across pregnancy by liquid chromatography coupled with tandem mass spectrometry. The Diet History Questionnaire II was completed by pregnant women at mid-pregnancy to assess dietary information. Linear mixed models were fitted to examine determinants of urinary phthalate metabolite concentrations. Using partial-linear single-index (PLSI) models, we assessed the major contributors, among ten food groups, to phthalate exposure. Metabolites of DEHP and its ortho-phthalate replacement, diisononyl phthalate (DiNP), were found in >90% of the samples. The sum of creatinine-adjusted DiNP metabolite concentrations was higher in older and single women and in samples collected in summer. Hispanic and non-Hispanic Black women had lower urinary concentrations of summed metabolites of di-n-octyl phthalate (DnOP), but higher concentrations of low molecular weight phthalates compared with non-Hispanic White women. Each doubling of grain products consumed was associated with a 20.9% increase in ∑DiNP concentrations (95%CI: 4.5, 39.9). PLSI models revealed that intake of dried beans and peas was the main dietary factor contributing to urinary ∑DEHP, ∑DiNP, and ∑DnOP levels, with contribution proportions of 76.3%, 35.8%, and 27.4%, respectively. Urinary metabolite levels of phthalates in pregnant women in NYC varied by age, marital status, seasonality, race/ethnicity, and diet. These results lend insight into the major determinants of phthalates levels, and may be used to identify exposure sources and guide interventions to reduce exposures in susceptible populations.

Exposure characteristics of phthalate metabolites among the Zunyi cohort of pregnant women in Southwest China

Reported evidence has increasingly indicated that exposure to phthalates can cause adverse pregnancy outcomes. However, phthalate exposure levels among pregnant women remains unclear. We aimed to evaluate the concentrations and predictors of phthalate metabolites in urine samples of the ongoing Zunyi cohort of pregnant women from Southwest China. The urine samples were collected from 1003 pregnant women during their third trimester of pregnancy. The concentrations of nine phthalate metabolites in urine samples were then determined. Data on socio-demographic profiles of the participants, lifestyle during pregnancy, parity, and sampling season were collected using questionnaires. The detectable rate of phthalate metabolites ranged from 76 to 100%. On average, mono-butyl phthalate exhibited the highest median concentration (62.45 μg/L), while mono-benzyl phthalate exhibited the lowest median concentration (0.04 μg/L). Urine concentrations of phthalate metabolites were significantly higher in older, multiparous, higher body mass index, higher income, and passive smoking during pregnancy participants. The levels of low-molecular-weight phthalate metabolites were highest during the summer. The findings indicate the health of pregnant women and fetuses in Zunyi may be generally harmed by the high exposure of phthalate metabolites, especially by mono-n-butyl phthalate. In addition, phthalate metabolites present a demographic and seasonal differential distribution among the study population. Targeted measures to reduce phthalate exposure for high-risk pregnant women and during high-exposure seasons may have potential benefits for maternal and fetal health protection.

Prenatal single and combined exposure to phthalates associated with girls' BMI trajectory in the first six years

Evidence of the influence of prenatal phthalate exposure on childhood longitudinal obesity markers is limited. Nested on the Ma'anshan birth cohort study, 990 mother-daughter pairs were included. Seven phthalate metabolites were determined in urine collected in each trimester. Each child underwent a physical examination from birth to 6 years of age twelve times. Latent class growth models were used to identify three trajectories of girls' body mass index (BMI). Logistic regression, quantile g-computation and Bayesian kernel machine regression models analyzed the relationships of prenatal exposure to individual and mixed phthalates with girls' body mass index (BMI) trajectory. Compared to the "lowest trajectory" class, prenatal average concentrations of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP, OR_crude = 2.095, 95 % CI = 1.014-4.328) and di(2-ethylhexyl) phthalate (DEHP, OR_crude = 2.336, 95 % CI = 1.022-5.338) during pregnancy were associated with an increased probability of being in the "highest trajectory" class. The average concentration of DEHP (OR_crude = 1.879, 95 % CI = 1.002-3.522) was associated with an increased probability of being in the "moderate trajectory" class. Stratified analyses by trimester of pregnancy mainly showed that third-trimester exposure to monoethyl phthalate (MEP, OR_adjusted = 1.584, 95 % CI = 1.094-2.292), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP, OR_adjusted = 2.885, 95 % CI = 1.367-6.088), MEHHP (OR_adjusted = 2.425, 95 % CI = 1.335-4.407), DEHP (OR_adjusted = 2.632, 95 % CI = 1.334-5.193) and high molecular weight phthalate (OR_adjusted = 2.437, 95 % CI = 1.239-4.792) was associated with an increased probability of being in the "highest trajectory" class. However, the mixture of phthalates was not significantly related to the girl's BMI trajectory. In conclusion, in utero exposure to phthalates, including MEP and DEHP metabolites (MEHHP and MEOHP), was significantly associated with early childhood high BMI trajectories in girls. The third trimester of pregnancy seemed to be the window of vulnerability to phthalate exposure for girls' high BMI trajectory at periods of prenatal development. No evidence supported a significant relationship between combined exposure to phthalate metabolites and girls' high BMI trajectory.

Lag associations of gestational phthalate exposure with maternal serum vitamin D levels: Repeated measure analysis

Few studies have investigated the relationships between gestational phthalate exposure and maternal circulating vitamin D. In the Ma'anshan birth cohort, 3265 pregnant women were included. Each woman provided up to three urine and serum samples for measurement of phthalates and 25(OH)D and calcium, respectively. Linear mixed models were performed to analyse the association between phthalate metabolites and 25(OH)D and calcium. Stratified analyses of the relationship between phthalates and 25(OH)D by urine collection season were conducted. Finally, the post hoc lag effect of phthalate exposure on 25(OH)D was determined if longitudinal associations were significant. Some phthalate metabolites were associated with increased 25(OH)D but with decreased calcium. Furthermore, the relationship of phthalate exposure with 25(OH)D varied with urine collection season. Phthalate metabolites collected in summer and autumn were associated with an increase in 25(OH)D, while monobenzyl phthalate collected in winter and spring was inversely associated with 25(OH)D. Finally, high-molecular-weight phthalates had lag associations with 25(OH)D with a 1-trimester lag period. Low-molecular-weight phthalates exhibited lag associations with 25(OH)D with a 2-trimester lag period. In conclusion, the positive cross-sectional correlation between phthalate metabolites and 25(OH)D was partly affected by urine collection season. This study suggested that gestational phthalate exposure would have a lag association with maternal 25(OH)D levels.

Effects of dibutyl phthalate and di (2-ethylhexyl) phthalate on hepatic structure and function of adult male mice

The objective of the present research was to determine if dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) alone and combined exposure induced pathological alterations in laboratory reared albino mice. Adult male mice were equally divided (n = 10) into Control, corn oil (CO), DBP, DEHP, and DBP+DEHP treated groups. Dibutyl phthalate (250 mg/kg), DEHP (300 mg/kg), and DBP+DEHP (250+300 mg/kg), respectively, were administered by oral gavage mixed in corn oil (0.2 mL) for 28 days. All animals were sacrificed following 28 days of treatment and blood was collected for serum lipid profiles and liver function tests. Liver samples were also collected for observation of histological changes. Microphotographs of hematoxylin and eosin-stained sections were used for computer-based micrometry. CO, DBP, DEHP, and DBP+DEHP treatment resulted in a significant increase in the mean body and liver weights as compared with the Control group. Histological examination of the livers with DBP and/or DEHP treatment showed marked alterations leading to hepatic hypertrophy. In the treated groups, a significant increase in the mean number of mononucleated, binucleated cells, and oval cells per unit area was noticed with disorganized trabecular arrangement as compared with the Control group. Treatment with DBP and/or DEHP resulted in large regeneration zones in the liver and an increased relative nucleo-cytoplasmic index of mononuclear shepatocytes when compared with the Control group. All treatments caused a significant increases in the liver enzymes and proteins as well as altered serum cholesterol, triglycerides, LDL, and VLDL levels. The histopathological and serological findings confirmed the toxic potentials to hepatic tissue of DBP and DEHP either given alone or in combination.

Urinary phthalate metabolites in pregnant women: occurrences, related factors, and association with maternal hormones

In this study, we aimed to evaluate phthalate metabolite levels in pregnant women, to explore the factors influencing exposure, and to assess phthalate metabolite levels in relation to thyroid hormone synthesis. We recruited 463 pregnant women and collected urine, blood, and questionnaire data at participant's first prenatal examination. Ten phthalate metabolites were analyzed: mono-isobutyl phthalate (MiBP); mono-methyl phthalate (MMP); mono-ethyl phthalate (MEP); mono-n-butyl phthalate (MnBP); mono-n-octyl phthalate (MOP); mono-benzyl phthalate (MBzP); and the metabolite of di-2-ethylhexyl phthalate (DEHP), which were mono (2-ethylhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, and mono-(2-ethyl-5-carboxypentyl) phthalate. Multivariable generalized estimating equation models and linear mixed models were used to predict urinary biomarker concentrations and to assess the associations between phthalate exposure and thyroid hormones. Positive associations were found between phthalate metabolites and lower education (MEP and MOP), living near the road (MEP, MnBP, and ∑DEHP), and consuming more puffed food (MEP and MBzP). In addition, MnBP (percent change [%△] = 4.25; 95% confidence interval [CI] = 0.32, 8.18) and ∑DEHP (%△ = 5.12; 95% CI = 1.25, 8.99) were positively associated with thyroid-stimulating hormones, although MEP and MnBP were inversely associated with free thyroxine and total triiodothyronine. Our findings suggest that certain habits and behaviors were predictive of the positive presence of phthalate metabolites and that certain phthalate esters are associated with altered thyroid hormone levels.

Identification of profiles and determinants of maternal pregnancy urinary biomarkers of phthalates and replacements in the Illinois Kids Development Study

BACKGROUND/OBJECTIVES

Pregnant women are exposed to multiple phthalates and their replacements, which are endocrine disrupting chemicals associated with adverse maternal and child health outcomes. Identifying maternal characteristics associated with phthalate/replacement exposure during pregnancy is important.

METHODS

We evaluated 13 maternal sociodemographic and lifestyle factors, enrollment year, and conception season as determinants of exposure biomarkers of phthalates and their replacements in 482 pregnant women from the Illinois Kids Development Study (I-KIDS, enrolled 2013-2018). We quantified 19 phthalate/replacement metabolites in pools of five first-morning urines collected across pregnancy. K-means clustering identified women with distinct patterns of biomarker concentrations and principal component analysis (PCA) identified principal component (PC) profiles of biomarkers that exist together. We used multivariable regression models to evaluate associations of predictors with identified k-means clusters and PCs.

RESULTS

K-means clustering identified two clusters of women: 1) low phthalate/di(2-ethylhexyl) terephthalate (∑DEHTP) and 2) high phthalate/∑DEHTP biomarker concentrations. PCA identified four PCs with loadings heaviest for biomarkers of plasticizer phthalates [di-isononyl, di-isodecyl, di-n-octyl phthalates] (PC1), of other phthalates [dibenzyl, di-n-butyl, di-iso-butyl phthalates] (PC2), of phthalate replacements [∑DEHTP, di(isononyl) cyclohexane-1,2-dicarboxylate (∑DiNCH)] (PC3), and of monoethyl phthalate [MEP] (PC4). Overall, age, marital status, income, parity, pre-pregnancy BMI, caffeine intake, enrollment year, and conception season were independently associated with k-means cluster membership and at least one PC. Additionally, race/ethnicity, education, employment, pregnancy intention, smoking status, alcohol intake, and diet were associated with at least one PC. For instance, women who conceived in the spring, summer, and/or fall months had lower odds of high phthalate/∑DEHTP cluster membership and had lower plasticizer phthalate, phthalate replacement, and MEP PC scores.

CONCLUSIONS

Conception season, enrollment year, and several sociodemographic/lifestyle factors were predictive of phthalate/replacement biomarker profiles. Future studies should corroborate these findings, with a special focus on replacements to which pregnant women are becoming increasingly exposed.

Prenatal phthalate exposure associated with age-specific alterations in markers of adiposity in offspring: A systematic review

Childhood obesity and metabolic disorders are of concern and are public health problems globally. Environmental endocrine disruptors, including phthalates, are well known as "obesogens" and "metabolic disruptors". Several studies have investigated the relationships between prenatal phthalate exposure and childhood obesity with inconsistent conclusions. Given the child growth trajectory/pattern as a possible early marker of metabolic disorders, we aimed to assess the effect of prenatal phthalate exposure on offspring growth trajectory. A systematic literature search was conducted using MEDLINE (accessed through PubMed), Web of Science, and CNKI (Chinese National Knowledge Infrastructure) until July 2021. We evaluated the risk of bias for adherence to the prespecified criteria. Fourteen eligible articles were finally included in this systematic review according to the defined PECOS statement. The risk of bias of the included studies was "low" or "probably low", and few were "probably high" and "high". These studies were mostly carried out in the United States (N = 6); others were conducted in China (N = 2), Mexico (N = 2), France (N = 1), Spain (N = 1), Greece (N = 1), and Australia (N = 1) and published from 2015 to 2021. The combined subjects of the 14 studies were 10,396 mother-child pairs. Except for 3 studies not reporting the sex ratio, at least 4001 boys and 3366 girls were included. For the association of prenatal phthalate exposure with an absolute adiposity marker (at a specific visit timepoint), only a few studies were using the same obesity marker as the outcome endpoint and using the same statistical method to explore their associations. However, MEP appeared to be positively associated with several obesity markers, such as the absolute BMI z score, weight-for-age z score, waist circumference, and overweight status. For the association of prenatal phthalate exposure with a repeated measurement of the adiposity marker over the age range, neither associations of adiposity markers with a specific phthalate metabolite nor relationships of a specific adiposity marker with prenatal phthalate exposure were of a consistent result. All four articles reported that phthalate metabolite exposure during pregnancy was associated with children's growth trajectory. Three suggested a sex-specific association between prenatal phthalate exposure and obesity trajectory. In conclusion, the current articles did not show any relationship between prenatal phthalate exposure and children's age-specific outcomes, except for positive associations of prenatal MEP exposure with absolute adiposity markers. However, epidemiological data supported a weak relationship between prenatal phthalate exposure and children's obesity trajectory in a sex-specific manner.

Sex-specific mediation of placental inflammatory biomarkers in the effects of prenatal phthalate coexposure on preschooler cognitive development

The objective of this study is to investigate the mediating effect of placental inflammatory biomarkers on the relationship between prenatal phthalate coexposure and cognitive development in preschoolers. A subgroup of 1660 mother-child pairs from the Ma'anshan Birth Cohort study were included. We measured the levels of phthalate metabolites of dibutyl phthalate (DBP), butyl benzyl phthalate (BBzP), and di (2-ethylhexyl) phthalate (DEHP) in all the women included in the study from three urine samples collected in each of the trimesters. A potency-weighted sum of coexposure to DBP, BBzP, and DEHP (indicator: ∑PAE) was calculated. The mRNA of the proinflammatory cytokine IL-6 and the classically activated macrophage (M1) biomarker CD68 was analyzed using placental tissues. The Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition-Chinese was used to evaluate the full-scale intelligence quotient (FSIQ) of children aged 2.5-6 years. Average ∑PAEs and ∑PAEs in each trimester were associated with IL-6 and CD68. ∑PAE in the first trimester was positively associated with IL-6 (β = 0.11, 95% CIs = 0.03-0.19) and CD68 (β = 0.16, 95% CIs = 0.04-0.28), and negatively associated with FSIQ (β =-0.06, 95% CIs = -0.11 to -0.02), verbal comprehension (β =-0.06, 95% CIs = -0.11 to -0.01), and processing speed (β =-0.07, 95% CIs = -0.12 to -0.01). Additionally, sex discrepancies were observed for the mediating effects of placental inflammation on the relationships between ∑PAE and children's cognitive development. For instance, the association between ∑PAE in early pregnancy and FSIQ was partially mediated by IL-6 (estimated proportion mediated: 21.85%) and CD68 (estimated proportion mediated: 16.2%). Gender-specific associations and trimester-specific relationships of prenatal multiple phthalate coexposure were revealed. ∑PAE in the first trimester of pregnancy was associated with increased of placental inflammation, and a decrease in preschoolers' cognitive development. In boys, placental IL-6 and CD68 elevation resulting from phthalates might be potential mechanisms of poor cognitive development.

Effects of single and combined gestational phthalate exposure on blood pressure, blood glucose and gestational weight gain: A longitudinal analysis

Few studies have investigated the association of gestational exposure to phthalate with metabolic risk and have reached inconsistent conclusions. Based on the Ma'anshan Birth Cohort, 3273 women were included in the present study. All participants provided up to three urine samples for 7 phthalate metabolite measurements. The hazard index (HI) was used to evaluate the cumulative risk of multiple phthalate coexposures. The outcomes of interest included hypertensive disorders of pregnancy (HDOP), gestational diabetes mellitus (GDM), and gestational weight gain (GWG). The incidences of HDOP, GDM, and excessive GWG were 5.93%, 13.09%, and 28.95%, respectively. Exposure to a single phthalate metabolite or a specific diester during the first trimester of pregnancy elevated blood pressure (BP) and fasting plasma glucose (FPG) in the third trimester and body weight gain throughout pregnancy. However, inverse relationships were revealed for some phthalate metabolites, which were inconsistent with the results of their diesters. The HI value during the first trimester was positively associated with subsequent BP, FPG, and GWG. In addition, HI during the first trimester increased the risks of GDM [odds ratio (OR) = 1.34, 95% confidence intervals (CIs) = 1.02-1.75)] and excessive GWG (OR = 1.76, 95% CIs = 1.41-2.19) in a linear manner thereafter. Notably, phthalates might directly increase maternal blood glucose and pressure, and these changes were secondary effects of the obesiogenic effects of certain phthalates. In conclusion, exposure to single and multiple phthalates during the first trimester of pregnancy increased the risks of maternal metabolic syndrome components. However, the conflicting findings between phthalates and their metabolites need to be interpreted carefully.

Effect of phthalates exposure during perinatal period on hormonal profile in Mexican males during their first months of life

Phthalates affect development of male reproductive system acting as an antiandrogenic agents. We sought to explore if perinatal exposure to phthalates could alter male hormone levels in humans during the first months of life. A cohort of 83 pregnant women and their male infants were studied. Five phthalate metabolites were measured in the mother's urine during the first, second, and third trimesters of pregnancy and during the first, third, and sixth months of life in the infants. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone and inhibin B were analyzed. Association between phthalate exposure and hormone variation was assessed using regression models for longitudinal data. Mono-butyl phthalate reduced FSH concentration (ß = -0.0012 international units [IU]/L, p < 0.01), mono-ethylhexyl phthalate reduced inhibin B (ß = -0.0094 pg/mL, p = 0.02), monoethyl phthalate reduced testosterone (ß = -0.0071 ng/L, p = 0.07), mono-ocytl phthalate reduced LH (ß = -0.0041 IU/L, p = 0.13). No effects were observed for exposure to mono-methyl phthalate. Our results are consistent with the findings in animal and human studies. Special precaution should be taken when measuring phthalate exposure in susceptible populations such as pregnant women and infants.

Trimester-specific and sex-specific effects of prenatal exposure to di(2-ethylhexyl) phthalate on fetal growth, birth size, and early-childhood growth: A longitudinal prospective cohort study

Prenatal exposure to di(2-ethylhexyl) phthalate (DEHP) may cause adverse health outcomes. However, trimester-specific impacts of DEHP exposure on offspring growth from fetal to early childhood stage have not been thoroughly evaluated. In this study, participants who provided a full series of urine specimens at three trimesters were selected from a birth cohort conducted at Wuhan, China from 2014 to 2015. 814 mother-offspring pairs were included in the study. Urinary concentrations of DEHP metabolites were determined using liquid chromatography-tandem mass spectrometry. Z-scores for ultrasound-measured fetal growth parameters at 14.0-18.9, 22.6-27.0, and 29.0-33.9 weeks of gestation, were calculated. Weight, height, and body mass index (BMI) at 6, 12, and 24 months were standardized to z-scores using sex-specific and age-specific WHO child growth standards. Linear regressions with generalized estimating equations were used to assess the relationships of DEHP levels per trimester to fetal growth, birth size, and growth at 6, 12, and 24 months to explore the trimester-specific impacts of DEHP exposure on offspring development. Among males, the1^st-trimester DEHP was negatively related to fetal growth (β < 0, p < 0.05), but positively related to 24-month BMI. The 2nd-trimester DEHP was negatively related to birth weight and birth length, but positively related to weight gain rates from birth to 24 months old. The 3rd-trimester DEHP was positively (β > 0, p < 0.05) associated with birth weight and BMI at 6 and 12 months. Among females, the 1st-trimester DEHP was associated with increased birth length, while the 2nd-trimester DEHP was negatively associated with BMI at 6 and 12 months. A negative association between DEHP and weight gain rates at 6 months was noted among females. This prospective cohort revealed the sex-specific and trimester-specific relationships of DEHP exposure to offspring growth from fetal to early-childhood stage.

Biomarkers of phthalates and alternative plasticizers in the Flemish Environment and Health Study (FLEHS IV): Time trends and exposure assessment

Restrictions on the use of legacy phthalate esters (PEs) as plasticizer chemicals in several consumer products has led to the increased use of alternative plasticizers (APs), such as di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH) and di-(2-ethylhexyl) terephthalate (DEHTP). In the fourth cycle of the Flemish Environment and Health Study (FLEHS IV, 2016-2020), we monitored exposure to seven PEs (diethyl phthalate (DEP), di-(2-ethylhexyl) phthalate (DEHP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBzP, di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP))and three APs (DINCH, DEHTP, and di-(2-ethylhexyl) adipate (DEHA)) by measuring multiple biomarkers in urine of 416 adolescents from Flanders, Belgium (14-15 years old). The reference values show that exposure to PEs is still widespread, although levels of several PE metabolites (e.g., sum of DEHP metabolites, mono-normal-butyl phthalate (MnBP) and mono-benzyl phthalate (MBzP)) have decreased significantly compared to previous human biomonitoring cycles (2003-2018). On the other hand, metabolites of DINCH and DEHTP were detected in practically every participant. Concentrations of AP exposure biomarkers in urine were generally lower than PE metabolites, but calculations of estimated daily intakes (EDIs) showed that exposure to DINCH and DEHTP can be considerable. However, preliminary risk assessment showed that none of the EDI or urinary exposure levels of APs exceeded the available health-based guidance values, while a very low number of participants had levels of MiBP and MnBP exceeding the HBM value. Several significant determinants of exposure could be identified from multiple regression models: the presence of building materials containing PVC, ventilation habits, socio-economic status and season were all associated with PE and AP biomarker levels. Cumulatively, the results of FLEHS IV show that adolescents in Flanders, Belgium, are exposed to a wide range of plasticizer chemicals. Close monitoring over the last decade showed that the exposure levels of restricted PEs have decreased, while newer APs are now frequently detected in humans.

Association between prenatal phthalate exposure and gestational metabolic syndrome parameters: a systematic review of epidemiological studies

The relationship of intrauterine phthalate exposure with gestational metabolic syndrome (GMS) parameters is inconsistently reported. We performed a systematic review to evaluate the association between prenatal phthalate exposure and GMS parameters. A literature search was performed in three databases. According to the defined PECOS statement, eligible studies were identified. The method and result for each study was qualitatively summarized with great emphasis on study design and exposure assessment. Fourteen studies were included in the present systematic review. Two studies used one-spot serum sample for evaluation of phthalate exposure, while others used 1-4 urine samples. Concentrations of phthalate metabolites varied substantially, and the levels in serum were greatly lower than those in urine. These studies observed no interstudy or intrastudy consistency for association between phthalates and GMS in pregnant women cross-sectionally or longitudinally, regardless of phthalates species or GMS indicator. Most reported associations were not significantly different from null result. Besides, positive and negative relationships also existed. The current epidemiological data do not support the hypothesis that prenatal exposure to phthalates increases GMS risk.

Moderating effects of plastic packaged food on association of urinary phthalate metabolites with emotional symptoms in Chinese adolescents

Previous research reports that diet is the main source of phthalate exposure to adolescents, and phthalate is associated with adolescent mental and behavioral problems. However, no study has explored the moderating effects of eating behavior in this association. This study aimed to analyze the moderating effects of plastic packaged food consumption in the longitudinal association between phthalate metabolite concentration and emotional symptoms in adolescents. This school-based survey was carried out among adolescents in two Chinese provinces. We conducted a baseline and follow-up surveys for 893 freshmen using the purposive sampling method from December 2018 to November 2019. We used food frequency questionnaire to assess eating behavior. The Chinese version of 21-item Depression Anxiety Stress Scales was used to assess emotional symptoms, and high-performance liquid chromatography-tandem mass spectrometry was used to analyze the concentration of six urine phthalate metabolites. The results of latent moderation model indicated that plastic packaged food consumption moderated the association of low molecular weight phthalate (LMWP) with depressive symptoms (β = 0.27, P = 0.002), anxiety symptoms (β = 0.89, P < 0.01), and stress symptoms (β = 0.23, P = 0.019). The moderating effects were significant at the higher scores (β = 0.14-0.35, P < 0.05) and/or the lower scores (β = -0.35 to -0.12, P < 0.05) of plastic packaged food consumption. The results suggest that plastic packaged food consumption to some extent moderates the longitudinal association of phthalate exposure with emotional symptoms in adolescents.

Maternal Food and Beverage Consumption Behaviors and Discrepant Phthalate Exposure by Race

Background: Differential exposure to endocrine-disrupting chemicals, including phthalate diesters, may contribute to persistent racial/ethnic disparities in women’s reproductive health outcomes. We sought to characterize sources of gestational exposure to these agents that may differ according to maternal race. Methods: We enrolled pregnant Black (n = 198), including African American, and White (n = 197) women during the second trimester, and measured eight phthalate monoester metabolites in urine. We assessed confounder-adjusted associations between multiple food and beverage consumption habits, summarized using a principal component analysis, as predictors of maternal urinary phthalate metabolite levels, stratified by race. Results: Whites reported significantly greater unprocessed food consumption (42.5% vs. 32.0%; p < 0.001) and storage of food in clear unbreakable plastic containers (66.5% vs. 49.3%; p < 0.001) than Blacks, while Blacks consumed more canned fruits and vegetables (23.5% vs. 12.2%; p < 0.001) than Whites. Using plastics for food storage, microwaving in plastic containers, and using hard plastic water bottles was associated with urinary phthalate concentrations, especially DEHP metabolites (e.g., mean difference = 5.13%; 95% CI: 3.05, 7.25). These associations were driven primarily by Black pregnant women. Conclusions: Targeted interventions to reduce maternal exposure to phthalates need to be designed with specific attention to differences in food and beverage consumption behaviors among Black and White women.

Seasonal exposure to phthalates and inflammatory parameters: A pilot study with repeated measures

Exposure to phthalates poses potential to damage multiple organs and system in the body. However, limited data are available regarding effects of seasonal exposure levels of phthalates and indicators reflecting inflammatory response. We designed a pilot study with repeated measures. We recruited 106 eligible habitants from Wuhan city, China. They completed questionnaires, physical examinations and provided urine specimens in winter and summer seasons. We found that urinary levels of low-molecular-weight phthalate metabolites were higher in summer than in winter (all P < 0.01). In winter, an interquartile range increase (1.264 μg/L) in 3-day moving average of high-molecular-weight phthalate metabolites corresponded to a 13.634% (95% CI: -22.331, -3.941) decrease in mean platelet volume, 25.879% (95% CI: -37.424, -12.204) for lymphocyte count or 10.862% (95% CI: -18.716, -2.125) for platelet count (P < 0.05 or P < 0.01). However, in summer, an interquartile range increase (1.215 μg/L) in urinary levels of high-molecular-weight phthalate metabolites corresponded to an 8.743% (95% CI: 4.217, 13.467) increase in platelet distribution width value or a 4.597% (95% CI: 2.335, 6.780) for mean platelet volume value at 3-day lag (both P < 0.01). In conclusion, phthalate exposure exhibited the potential for the activation of platelet function, particularly in winter. Seasonal variations of phthalate exposure should be considered when assessing health risk.

Early childhood screen time as a predictor of emotional and behavioral problems in children at 4 years: a birth cohort study in China

BACKGROUND

Previous studies have suggested that screen time (ST) has a negative effect on children's emotional and behavioral health, but there are few longitudinal studies that have been conducted with infants and toddlers. This study sought to examine the effect of ST in early childhood on emotional and behavioral problems in children aged 4 years, based on a birth cohort study in China.

METHODS

A total of 2492 children aged 4 years were enrolled in this study. The parents and guardians of each child completed a questionnaire that included items eliciting information on children's birth information, socio-demographic information at baseline, and ST at each follow-up. Emotional and behavioral problems were assessed using the Strengths and Difficulties Questionnaire (SDQ) at 4 years of age. Multivariate logistic analysis was used to explore the effects of ST on emotional and behavioral problems.

RESULTS

The percentages of children with ST > 0 h/day at age 0.5 years, ST > 2 h/day at age 2.5 years, and ST > 2 h/day at age 4 years were 45.7, 55.5, and 34.5% respectively. The prevalence of emotional and behavioral problems was 10.8%. ST at 6 months was a risk factor for emotional symptoms and hyperactivity at the age of 4 years. ST at age 2.5 years was a risk factor for hyperactivity at the age of 4 years. However, ST at age 4 years was a risk factor for total difficulties, conduct problems, peer problems, hyperactivity, and prosocial behavior.

CONCLUSIONS

Higher ST exposure at early childhood is associated with later emotional and behavioral problems. In particular, sustained high ST exposure is a risk factor for behavioral problems. These findings suggested the importance of controlling ST to prevent the occurrence of emotional and behavioral problems in the early years.

Phthalate levels in urine of pregnant women and their associated missed abortion risk

Phthalates are one of the most common environmental endocrine disrupting chemicals (EDCs) in human contact. Prenatal phthalates exposure may adversely affect intrauterine growth, however, little is known about their association. This study aimed to explore the impact of phthalates on the risk of missed abortion. A total of 123 women with missed abortion (cases) and 148 normal pregnant women (controls) were simultaneously collected from Taiyuan, China. Four urinary phthalate metabolites were determined by high-performance liquid chromatography (HPLC). Logistic regression model was used to estimate odds ratios (ORs) and 95 % confidence intervals (95 % CI) of missed abortion associated with phthalate metabolite levels. Four phthalate metabolites, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), were detected in at least 78.97 % of all participants, with the highest geometric mean concentration of 147.19 ng/mL for MEP of the urine samples. Both MMP (Z = -3.898, P < 0.001) and MBP (Z = -2.198, P = 0.028) concentrations were higher in cases than in controls. There were no significant differences for MEP (Z = -0.285, P = 0.076) and MBzP (Z = -0.878, P = 0.380) concentrations between cases and controls. Furthermore, Logistic analysis revealed that each one-unit increase in log-transformed MMP (OR = 1.49, 95 % CI = 1.14-1.95) was positively associated with missed abortion. Increasing risks of missed abortion were observed the third quartile (Q3) and the highest quartile (Q4) of MMP(OR = 2.21, 95 % CI = 1.06-4.60; OR = 2.85, 95 % CI = 1.34-6.05) compared to the lowest quartile (Q1) of MMP concentrations. We concluded that prenatal phthalates exposure may contribute to an increased risk of missed abortion.

Urinary antibiotic exposure across pregnancy from Chinese pregnant women and health risk assessment: Repeated measures analysis

Multiple antibiotics are widely used in clinic practice and livestock husbandry, but exposure data based on repeated measurements are scarce among pregnant women. Here, we biomonitored 41 antibiotics and their two metabolites in urine samples from 3235 pregnant women over three trimesters. Spearman's correlation coefficient, intraclass correlation coefficient (ICC), percentile analysis and linear mixed models were employed to evaluate the correlations, variability, co-exposure patterns and predictors of antibiotics, respectively. Pregnant urinary creatinine-adjusted concentrations of antibiotics were used to estimate daily exposure dose and assessed health risks. The target antibiotics were detected in more than 90% of urine samples, primarily as preferred as veterinary antibiotics (PVAs), and the 95th percentile urinary concentrations of each individual antibiotics were range from below the limits of detection to 5.74 ng/mL. We observed considerable within-subject variation (ICC: 0.05-0.63) of urinary antibiotics concentrations during pregnancy. More than half pregnant women were co-exposed to two or more antibiotics of different usage classes, while both co-exposure to high percentiles of three usage antibiotics at one trimester or exposure to single usage antibiotics at high-dose through three trimesters were infrequent in the study population, and most pregnant women were continuously exposed to low-dose PVAs across pregnancy. A total of 4.5% samples were showed hazard index values exceeding 1 during entire pregnancy. Urinary levels of antibiotics associated with residence, maternal age and education, pre-pregnancy BMI, household income and gestational week, especially vary by sampling seasons. Taken together, most pregnant women were frequently exposure to low-dose PVAs across pregnancy and some were in a health risk associated with the disturbance of gut microbiota. Multiple measurements of urinary antibiotic concentrations are essential to more accurate charactering the exposure levels during pregnancy. Several predictors of urinary antibiotics should be taken into consideration in future researches.

Sex-specific difference in placental inflammatory transcriptional biomarkers of maternal phthalate exposure: a prospective cohort study

Previous epidemiologic research has shown that phthalate exposure in pregnant women is related to birth outcomes in a sex-specific manner. These outcomes may be mediated by placental inflammation, which is the proposed biological mechanism. This is the first study to address the relationship between phthalate exposure and gene expression in placental inflammation in a sex-specific manner. We performed quantitative PCR to measure placental inflammatory mRNAs (CRP, TNF-α, IL-1β, IL-6, IL-10, MCP-1, IL-8, CD68, and CD206) in 2469 placentae that were sampled at birth. We estimated the associations between mRNA and urinary phthalate monoesters using multiple linear regression models. Mono-n-butyl phthalate (MBP) was correlated with higher IL-1β, IL-6, and CRP expression in placentae of male fetuses and with higher IL-6, CRP, MCP-1, IL-8, IL-10, and CD68 expression in placentae of female fetuses. Mono benzyl phthalate (MBzP) increased the expression of TNF-α, MCP-1, and CD68 only in placentae of male fetuses. Mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) was negatively correlated with CRP, MCP-1, and CD68 in placentae of female fetuses. Maternal phthalate exposure was associated with inflammatory variations in placental tissues. The associations were stronger in placentae of male than of female fetuses. Compared with the other metabolites, MBP plays a strong role in these associations. The placenta is worth being further investigated as a potential mediator of maternal exposure-induced disease risk in children.

Domain- and trimester-specific effect of prenatal phthalate exposure on preschooler cognitive development in the Ma'anshan Birth Cohort (MABC) study

BACKGROUND

Phthalates are a group of heavily produced endocrine disruptors that are widely used in personal care products, food packaging, building materials, and medical device. Few epidemiological studies have examined the effect of repeated prenatal exposure to multiple phthalates on preschooler cognitive development.

OBJECTIVES

This study aimed to examine the association between prenatal phthalate exposure measured at multiple time points and the intelligent quotient (IQ) scores of preschoolers, and to further identify the critical windows and specific intelligence domains in which phthalate exposure would affect preschooler cognitive development.

METHODS

The current study was based on the Ma'anshan Birth Cohort (MABC) study. Seven phthalate metabolites were measured in 2128 maternal urine samples collected during the first, second, and third trimesters of pregnancy. The IQ score of preschool-aged children were assessed with the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence, Fourth edition (WPPSI-Ⅳ CN). Linear mixed models (LMMs) were used to assess the longitudinal effects of repeated prenatal phthalate exposure on children's IQ score. Multiple linear regression models were fitted to determine whether critical window phthalate exposure would affect cognitive development of children.

RESULTS

Overall, the repeated measures analysis indicated that the verbal comprehension index (VCI), visual space index (VSI) and full-scale intelligence quotient (FSIQ) decreased by 0.30 (95% CI: -0.60, 0; p = 0.05), 0.32 (95% CI: -0.62, -0.01; p = 0.04), and 0.31 (95% CI:-0.57, -0.04; p = 0.02) points, respectively, with each ln-transformed increase in the metabolite concentration of MBP. The fluid reasoning index (FRI) and processing speed index (PSI) increased by 0.30 (95% CI: 0.07, 0.54; p = 0.01) and 0.28 (95% CI: 0.06, 0.51; p = 0.01) points, respectively, with each ln-concentration increase in MEP. Trimester-specific regression models stratified by the sample collection time during pregnancy generated consistent results. In the first trimester, each ln-transformed MBP increase was associated with reductions in VCI, VSI and FSIQ of 0.56 (95% CI:-1.09, -0.02; p = 0.04), 0.60 (95% CI:-1.15, -0.05; p = 0.03) and 0.49 (95% CI:-0.97, -0.01; p = 0.04) points, respectively. In the third trimester, we observed that only MBzP exposure was associated with an increase in VCI (β: 0.48, 95% CI: 0.03, 0.92; p = 0.04). The gender-stratified analyses revealed that boys drove these associations.

CONCLUSIONS

Our results suggest that prenatal phthalate exposure impairs the cognitive development of preschoolers. The first trimester of pregnancy might be the most vulnerable period in terms of neurotoxicitydue to phthalate exposure. These findings warrant further confirmation.

Airborne phthalates in indoor environment: Partition state and influential built environmental conditions

Exposure to phthalates has recently become a major public health concern. The information of indoor airborne phthalates and their air-particle partition in real indoor environmental condition is still limited. In this study, the gas- and PM_2.5-concentrations of 7 phthalates in 40 residences were concurrently measured in summer and winter. The major phthalates (median concentration in the summer and winter, respectively) in indoor air were DMP (2442.3 and 2403.4 ng/m³), DiBP (801.0 and 640.0 ng/m³) and DnBP (5173.2 and 1379.6 ng/m³), whereas the major phthalates in PM_2.5 were DiBP (1055.1 and 585.9 ng/m³) and DnBP (1658.5 and 1517.0 ng/m³) and DEHP (215.1 and 344.9 ng/m³). Air-PM_2.5 partition coefficients (K_p) of DiBP, DnBP and DEHP were calculated: the summer and winter median values (m³/μg) were 0.053 and 0.011 for DiBP, 0.010 and 0.004 for DnBP, 0.021 and 0.025 for DEHP, respectively. Air-PM_2.5 partition of DiBP and DnBP approached equilibrium, while that of DEHP did not reach equilibrium in either season. The impacts of built environmental conditions on phthalate concentrations were characterized. Elevated temperature resulted in accumulation of airborne phthalates. Higher air humidity led to more water absorption of aerosols in summer, facilitated mass transfer of phthalates from air to PM_2.5, and resulted in greater K_p of DiBP and DnBP in the summer. Any factors such as proximity to local traffic highway and indoor smoking activities, which can increase indoor PM_2.5 concentrations, resulted in significantly higher airborne phthalate concentrations. Improving ventilation was not an effective measure to reduce indoor airborne phthalate concentrations.

Association of urinary phthalates metabolites concentration with emotional symptoms in Chinese university students

Previous studies have shown the associations between phthalates exposure and psychological behavior problems in children and adolescents, but such associations have not been fully elucidated in university students, especially among Chinese university students. This study aims to examine the association between urinary phthalates metabolites concentration and emotional symptoms in Chinese university students. A school-based cross-sectional survey was carried out among 990 university students aged 17-24 years from two universities in Anhui and Jiangxi provinces of China. Concentration of six phthalate metabolites in urine was determined by high-performance liquid chromatography-tandem mass spectrometry and the emotional symptoms were assessed by the 21-item Depression, Anxiety, and Stress Scale. The detection rate of six phthalate metabolites in urine ranged from 79.6% to 99.7%. The median concentration of six phthalate metabolites ranged from 2.90 to 119.64 ng/mL. The positive rates of depressive symptoms, anxiety symptoms, and stress were 17.4%, 24.8%, and 9.5%, respectively. After adjusting for the confounding variables, mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was found to be associated with depressive symptoms (β = 8.84, P = 0.017), anxiety symptoms (β = 8.46, P = 0.015), and stress symptoms (β = 9.95, P = 0.012) in males; whereas, monobutyl phthalate (MBP) was found to be associated with depressive symptoms (β = 1.86, P = 0.002), anxiety symptoms (β = 1.81, P = 0.005), and stress symptoms (β = 1.48, P = 0.047) in females. Our study demonstrates that Chinese university students are widely exposed to phthalates; and high- and low-molecular weight phthalates are associated with emotional symptoms in males and females, respectively.

Repeated measures of prenatal thallium exposure and placental inflammatory cytokine mRNA expression: The Ma'anshan birth cohort (MABC) study

Thallium (Tl), a ubiquitous environmental toxicant, can cross the placental barrier during pregnancy. However, the effects of prenatal Tl exposure on placental function are currently unclear. Based on the Ma'anshan Birth Cohort study, we examined whether long-term prenatal Tl exposure was associated with placental inflammation. Tl concentrations were quantified in serum samples (n = 7050) from 2515 pregnancy during each trimester, placental inflammatory cytokine mRNA expression was assessed in 2519 placenta tissues. Geometric mean values of serum Tl concentrations were 63.57, 63.63 and 48.71 ng/L for the first, second and third trimesters, respectively. After adjustment for potential confounders, serum Tl concentration was positively associated with CD68 (β: 0.30; 95% CI: 0.05, 0.56) in the first trimester and TNF-α (β: 0.12; 95% CI: 0.01, 0.23), IL-6 (β: 0.15; 95% CI: 0.05, 0.25) and CD68 (β: 0.25; 95% CI: 0.10, 0.39) in the third trimester, however was negatively associated with IL-4 (β: -0.21; 95% CI: -0.41, -0.01) and CD206 (β: -0.23; 95% CI: -0.45, -0.02) in the first trimester. Repeated measures analysis showed that TNF-α, IL-6 and CD68 increased by 0.11 (95% CI: 0.01, 0.21), 0.12 (0.15, 95% CI: 0.05, 0.25), 0.22 (95% CI: 0.10, 0.39), respectively, with each 1ln-transformed Tl increase in total samples. Gender-specific analyses revealed that these associations were largely driven by male offspring. In addition, immunohistochemistry revealed that nuclear NF-κB p65 expression increased in placenta tissue. The results of this prospective cohort study provide longitudinal evidence that prenatal Tl exposure induces a placental inflammatory response in the Chinese population.

Urinary levels of phthalate metabolites in women associated with risk of premature ovarian failure and reproductive hormones

Phthalates, a class of high production-volume chemicals widely used as plasticizers, have been shown to impair ovarian functions in female animals, but epidemiological evidence is very limited. In this case-control study, the associations between phthalate exposure and premature ovarian failure (POF) in women were assessed. A total of 173 POF cases and 246 control women were recruited in Zhejiang, China. The urinary concentrations of 8 phthalate metabolites and the serum levels of ovary-related hormones were determined. Mono-isobutyl phthalate (MiBP) was the metabolite with the highest median concentration of 27.23 μg/g of creatinine in the whole group. Compared with the lowest quartile, higher urinary concentrations of MiBP were significantly associated with increased odds of POF (OR = 1.38, 95% CI: 0.73-2.61 for the fourth quartile; p for trend = 0.01). The estradiol/FSH ratio, a marker of ovarian function, in control women was significantly negatively associated with the urinary concentrations of most tested phthalate metabolites. Our results suggest that exposure to some phthalates may impair ovarian function and increase the odds of POF in women.

Endocrine-Disrupting Chemicals in Human Fetal Growth

Fetal growth is regulated by a complex interaction of maternal, placental, and fetal factors. The effects and outcomes that chemicals, widely distributed in the environment, may have on the health status of both the mother and the fetus are not yet well defined. Mainly mixtures of chemical substances are found in the mothers and placenta. Exposure to endocrine-disrupting chemicals (EDCs) can be associated with fetal growth retardation, thyroid dysfunction, and neurological disorders. EDCs mostly interfere with insulin, glucocorticoid, estrogenic, and thyroid pathways, with subsequent effects on normal endocrine and metabolic functions, which cause changes in the epigenome and state of inflammation with life-long effects and consequences. International scientific societies recommend the implementation of research and of all possible preventive measures. This review briefly summarizes all these aspects.

Early life exposure to phthalates in the Canadian Healthy Infant Longitudinal Development (CHILD) study: a multi-city birth cohort

BACKGROUND

Few studies have examined phthalate exposure during infancy and early life, critical windows of development. The Canadian Healthy Infant Longitudinal Development (CHILD) study, a population-based birth cohort, ascertained multiple exposures during early life.

OBJECTIVE

To characterize exposure to phthalates during infancy and early childhood.

METHODS

Environmental questionnaires were administered, and urine samples collected at 3, 12, and 36 months. In the first 1578 children, urine was analyzed for eight phthalate metabolites: mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-3-carboxypropyl phthalate (MCPP). Geometric mean (GM) concentrations were calculated by age, together with factors that may influence concentrations. Trends with age were examined using mixed models and differences within factors examined using ANOVA.

RESULTS

The highest urinary concentration was for the metabolite MBP at all ages (GM: 15-32 ng/mL). Concentrations of all phthalate metabolites significantly increased with age ranging from GM: 0.5-15.1 ng/mL at 3 months and 1.9-32.1 ng/mL at 36 months. Concentrations of all metabolites were higher in the lowest income categories except for MEHP at 3 months, among children with any breastfeeding at 12 months, and in urine collected on dates with warmer outdoor temperatures (>17 °C), except for MBzP at 3 months and MEHP at 3 and 12 months. No consistent differences were found by gender, study site, or maternal age.

CONCLUSIONS

Higher phthalate metabolite concentrations were observed among children in lower income families. Examination of factors associated with income could inform interventions aimed to reduce infant phthalate exposure.

Determinants of exposure levels, metabolism, and health risks of phthalates among pregnant women in Wuhan, China

Concerns on minimizing health risks of phthalates have been raised due to their widespread exposure and well-documented endocrine disrupting properties, but the determinants of levels, metabolism, and health risks of phthalate exposures have not been thoroughly characterized among the Chinese population, particularly pregnant women. The metabolites of five phthalates were analyzed: diethyl (DEP), diisobutyl (DiBP), di-n-butyl (DnBP), di-(2-ethylhexyl) (DEHP), and benzyl butyl phthalate (BBzP) were analyzed in urine samples collected from 946 mothers in Wuhan during 2014-2015. We applied linear mixed models to investigate the relationships between biomarkers (e.g., urinary concentrations of phthalate metabolites, phthalates, and ratios of metabolites) and factors including sampling seasons and epidemiological characteristics. We calculated estimated daily intake (EDI) using average phthalate concentrations over three trimesters and hazard index (HI) by dividing EDI by tolerance daily intake. About 24.9% of participants were at health risks with HI > 1. The largest health risks were driven by one specific phthalate (DnBP or DEHP). We observed lower urinary levels of phthalate metabolites in winter. Elevated levels were found in mothers with higher education levels or those employed. Mothers who got pregnant on purpose had lower phthalate concentrations than those got pregnant by accident. More recent exposure to phthalates was observed among groups of mothers giving birth to girls, or those who got excessive gestational weight gain. Younger mothers were more susceptible to phthalate exposure. This repeated measurement study suggests that the intervention should be taken to limit application and production of DnBP and DEHP, and highlights that typical demographic factors should be taken into account in demographic studies.

Exposure to Mixed Phthalates in Czech Preschool and School Children

Knowledge of population exposure to phthalates based on the urinary metabolite levels is of the highest importance for health risk assessment. Such data are scarce in the Czech population. In the study conducted in 2016, six urinary phthalate metabolites were analysed in a total of 370 first morning urine samples of healthy children aged 5 and 9 years, namely mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP), mono-benzyl phthalate (MBzP), mono-iso-butyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP). The two latter mono-butyl phthalate isoforms dominated among all samples with geometric means of 63.0 µg/L (MnBP) and 44.1 µg/L (MiBP), followed by 5OH-MEHP (20.6 µg/L), 5oxo-MEHP (12.9 µg/L), MBzP (3.65 µg/L), and MEHP (2.31 µg/L). Daily intake (DI) of the parent phthalates was estimated using the creatinine-based model. The highest DI values were found for di-n-butyl phthalate (DnBP) (median 2.5 µg/kg bw/day; 95th percentile 7.8 µg/kg bw/day) and di-2-ethylhexyl phthalate (DEHP) (median 2.3 µg/kg bw/day; 95th percentile 8.9 µg/kg bw/day) in 5-year-old children. The tolerable daily intake (TDI) set by the European Food Safety Authority (EFSA) was exceeded in case of DnBP (in 1% of 9-year-olds and in 3% of 5-year-olds). Exposure risk was assessed based on hazard quotients calculation and cumulative approach for similar health effect. The combined exposure to four phthalates expressed by hazard index (HI) for reprotoxicity revealed exceeding of HI threshold in 14% of 5-year-olds and in 9% of 9-year-olds. These findings strongly support the need to reduce the burden of children by phthalates.

Seasonal modification of the associations of exposure to polycyclic aromatic hydrocarbons or phthalates of cellular aging

Exposure to polycyclic aromatic hydrocarbons (PAHs) and phthalates link to oxidative stress and inflammatory response, which exert cellular aging. However, modification effect of seasonal factor on the association of PAHs or phthalates exposure with relative telomere length (RTL) or mitochondrial DNA copy number (mtDNA-CN) has remained unclear. In this pilot study, 106 subjects were from an urban population (n = 1240) who lived in the two districts in Wuhan city, China. Participants completed physical examinations and provided 191 blood samples for RTL and mtDNA-CN analysis and 627 urine samples for monohydroxylated-PAHs (OH-PAHs) and phthalate metabolites measurements in the winter and summer seasons. We assessed the associations of urinary OH-PAHs or phthalates metabolites with RTL or mtDNA-CN by linear regression analysis and linear mixed-effect models. We found that urinary OH-PAHs were positively associated with mtDNA-CN at lag 2 day and 3-day moving average, but negatively related to RTL at lag 0, lag 1 and lag 2 day and 3-day moving average (p < 0.05). Urinary phthalate metabolites were negatively associated with mtDNA lag 0, lag 1 and lag 2 day and 3-day moving average, but positively related to RTL at lag 0 day (p < 0.05). Seasonal factor modified the association of urinary OH-PAHs with mtDNA-CN as well as urinary phthalate metabolites with RTL. In vitro experiment showed that under certain conditions, benzo[a]pyrene increased mtDNA-CN at 48 h and di (2-ethylhexyl) phthalate did RTL at 24 h in HepG2 cells. Seasonal variations in the metabolisms of PAHs or phthalates in human body may affect the relation of PAHs or phthalates exposure with cellular aging.

Prenatal phthalate exposure in relation to gestational age and preterm birth in a prospective cohort study

This study enrolled 3266 pregnant women, to explore the relationship of prenatal phthalate exposure with the risk of preterm birth and gestational age. All participants filled questionnaires and provided with up to three urine samples during three trimesters. Seven phthalate metabolites in urines were measured. The incidences of very preterm, late preterm, early-term, late-term and postterm births were 0.58%, 3.52%, 24.22%, 10.53%, and 0.34%, respectively. Non-linear relationships were shown between phthalate metabolites and gestational age. Except for monomethyl phthalate (OR = 1.65, 95%CI = 1.17-2.34), the average concentrations of phthalate metabolites were associated with a slightly and insignificantly increased risk of overall preterm birth (<37⁺⁰ gestational weeks). Through a restricted cubic spline regression, phthalate metabolites were found to be related to the risk of overall preterm birth in a linear manner (p-value >0.05) or a non-linear manner (p-value <0.05). All curves indicated the overall preterm birth risk rose with the increase of phthalate metabolite concentrations. Finally, compared with full-term birth (39⁺⁰ to 40⁺⁶ gestational weeks), phthalate metabolites were associated with the elevated risks of very preterm, late preterm and postterm births, although some relationships were not statistically significant. In conclusion, these findings suggested non-linear associations between phthalate metabolites and gestational age. Exposure to some phthalate metabolites was associated with increased risks of overall preterm birth and postterm birth.

Prenatal Exposure to Phthalates and Newborn Telomere Length: A Birth Cohort Study in Wuhan, China

BACKGROUND

Telomere length (TL) is a marker of biological aging and is inversely related to aging-related diseases. The setting of TL at birth may have important implications for lifelong telomere dynamics; however, its determinants remain poorly understood.

OBJECTIVES

The purpose of our study was to explore the relationships between prenatal exposure to phthalates and umbilical cord blood TL.

METHODS

A total of 762 mother–newborn pairs were recruited from a birth cohort study performed between November 2013 and March 2015 in Wuhan, China. Relative cord blood TL was measured using quantitative real-time polymerase chain reaction. Six phthalate metabolites were measured in urine samples acquired from pregnant women during the three trimesters. Multiple informant models were applied to estimate the associations between prenatal exposure to phthalates and cord blood TL and to evaluate potential windows of vulnerability.

RESULTS

Exposure to mono-ethyl phthalate (MEP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-butyl phthalate (MBP), and di(2-ethylhexyl) phthalate ([Formula: see text]) during the first trimester were inversely related to cord blood TL. In addition, we observed a female-specific association between maternal exposure to MEP during the first trimester and cord blood TL ([Formula: see text]). The associations between maternal exposure to MECPP, MEHHP, MEOHP, and [Formula: see text] during the first trimester and cord blood TL were consistent between males and females (all [Formula: see text]).

CONCLUSION

This prospective study demonstrated that prenatal exposure to some phthalate metabolites were associated with shorter cord blood TL. Our results, if confirmed in other populations, may provide more evidence of adverse health outcomes of phthalate exposure and support the hypothesis that the intrauterine environment may be one of the major determinants for newborn TL. https://doi.org/10.1289/EHP4492.