Association between urinary phthalates and phthalate metabolites and cancer risk: A systematic review and meta-analysis

Phthalates, widely utilized in industrial products, are classified as endocrine-disrupting chemicals (EDCs). Although certain phthalate and their metabolites have been implicated in cancer development, the reported findings have exhibited inconsistencies. Therefore, we conducted the comprehensive literature search to assess the association between phthalate and their metabolites and cancer risk by identifying original studies measuring phthalates or their metabolites and reporting their correlation with cancer until July 4, 2023. The Odds Ratios (ORs) and corresponding 95% confidence intervals (CIs) were extracted and analyzed to estimate the risk. Pooled data from eleven studies, including 3101 cancer patients and 6858 controls, were analyzed using a fixed- or random-effects model based on heterogeneity tests. When comparing extreme categories of different phthalates and their metabolites, we observed a significant association between urinary phthalates and phthalate metabolites (MEHHP, MECPP, DBP and MBzP) and cancer risk. The findings of our meta-analysis reinforce the existing evidence that urinary phthalates and phthalate metabolites is strongly associated with cancer development. Further investigations are warranted to elucidate the underlying mechanisms of this association. These results may offer novel insights into cancer development.

Associations between mixed exposure to phthalates and latent tuberculosis infection among the general U.S. population from NHANES 2011-2012

Background

People are constantly exposed to phthalates, but few reliable studies have focused on the connection between phthalate exposure and latent tuberculosis infection (LTBI).

Methods

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) database (2011-2012). The LTBI was assessed by QuantiFERON®-TB Gold-In-Tube (QFT) or tuberculin skin testing (TST). The odds ratios (ORs) and 95% confidence intervals (CIs) per log10 unit change in the concentration of phthalate metabolites were calculated using crude and adjusted logistic regression models. The relationships between mixed phthalate concentrations and LTBI were assessed using Bayesian kernel machine regression (BKMR) models.

Results

According to the results of the multivariable logistic regression, in a fully adjusted model, only monobenzyl phthalate (MBZP) was negatively associated with LTBI in Q3 (OR (95% CI): 0.485 (0.286,0.823), P = 0.007). According to the restricted cubic spline (RCS) model, there was a linear dose‒response association between all 11 phthalate metabolites and LTBI (p for nonlinearity >0.05). We found a significant positive correlation between mixed phthalate metabolites and LTBI by using fully adjusted BKMR model.

Conclusions

Our analysis demonstrated that LTBI in the general U.S. population is linearly linked with exposure to single or combined phthalates.

Phthalate exposure and blood pressure in U.S. children aged 8-17 years (NHANES 2013-2018)

BACKGROUND

Current evidence from epidemiologic studies suggested that phthalate metabolites might be associated with blood pressure (BP) changes. However, the special relationship between phthalate metabolites and BP changes in children has not been clearly elucidated in existing researches.

OBJECTIVES

We investigated the links between phthalate metabolites and various BP parameters, including systolic/diastolic BP, mean arterial pressure (MAP), and the presence of hypertension.

METHODS

The population sample consisted of 1036 children aged 8 to 17 years from the 2013-2018 NHANES in the United States. High performance liquid chromatography-electrospray ionization-tandem mass spectrometry was used to measure urinary concentrations of 19 phthalate metabolites. Systolic/diastolic BP were derived from the average of three valid measurements, and MAP was calculated as (systolic BP + 2 × diastolic BP)/3. Hypertension was defined as mean systolic BP and/or diastolic BP that was ≥ 95th percentile for gender, age, and height reference. Linear regression, logistic regression, and weighted quantile sum (WQS) regression models were employed to assess the associations between phthalate exposure and systolic/diastolic BP, MAP, and hypertension.

RESULTS

Ten of 19 phthalate metabolites including MCNP, MCOP, MECPP, MBP, MCPP, MEP, MEHHP, MiBP, MEOHP, and MBzP had detection frequencies > 85% with samples more than 1000. MCNP, MCOP, MECPP, MBP, MCPP, MEHHP, MiBP, MEOHP, and MBzP were generally negatively associated with systolic/diastolic BP and MAP, but not protective factors for hypertension. These associations were not modified by age (8-12 and 13-17 years) or sex (boys and girls). The above-mentioned associations were further confirmed by the application of the WQS analysis, and MCOP was identified as the chemical with the highest weight.

CONCLUSION

Phthalate metabolites were associated with modest reductions in systolic/diastolic BP, and MAP in children, while appeared not protective factors for hypertension. Given the inconsistent results among existing studies, our findings should be confirmed by other cohort studies.

Exposure assessment of plastics, phthalate plasticizers and their transformation products in diverse bio-based fertilizers

Bio-based fertilizers (BBFs) produced from organic waste have the potential to reduce societal dependence on limited and energy-intensive mineral fertilizers. BBFs, thereby, contribute to a circular economy for fertilizers. However, BBFs can contain plastic fragments and hazardous additives such as phthalate plasticizers, which could constitute a risk for agricultural soils and the environment. This study assessed the exposure associated with plastic and phthalates in BBFs from three types of organic wastes: agricultural and food industry waste (AgriFoodInduWaste), sewage sludge (SewSludge), and biowaste (i.e., garden, park, food and kitchen waste). The wastes were associated with various treatments like drying, anaerobic digestion, and vermicomposting. The number of microplastics (0.045-5 mm) increased from AgriFoodInduWaste-BBFs (15-258 particles g-1), to SewSludge-BBFs (59-1456 particles g-1) and then to Biowaste-BBFs (828-2912 particles g-1). Biowaste-BBFs mostly contained packaging plastics (e.g., polyethylene terephthalate), with the mass of plastic (>10 g kg-1) exceeding the EU threshold (3 g kg-1, plastics >2 mm). Other BBFs mostly contained small (< 1 mm) non-packaging plastics in amounts below the EU limit. The calculated numbers of microplastics entering agricultural soils via BBF application was high (107-1010 microplastics ha-1y-1), but the mass of plastic released from AgriFoodInduWaste-BBFs and SewSludge-BBFs was limited (< 1 and <7 kg ha-1y-1) compared to Biowaste-BBFs (95-156 kg ha-1y-1). The concentrations of di(2-ethylhexyl)phthalate (DEHP; < 2.5 mg kg-1) and phthalate transformation products (< 8 mg kg-1) were low (< benchmark of 50 mg kg-1 for DEHP), attributable to both the current phase-out of DEHP as well as phthalate degradation during waste treatment. The Biowaste-BBF exposed to vermicomposting indicated that worms accumulated phthalate transformation products (4 mg kg-1). These results are overall positive for the implementation of the studied AgriFoodInduWaste-BBFs and SewSludge-BBFs. However, the safe use of the studied Biowaste-BBFs requires reducing plastic use and improving sorting methods to minimize plastic contamination, in order to protect agricultural soils and reduce the environmental impact of Biowaste-BBFs.

Assessment of baby disposable diapers application for urine collection and determination of phthalate metabolites

The baby disposable diapers were investigated as a sampling material for urine collection and validated for the evaluation of the exposure of children to xenobiotics. Phthalate metabolites detected in urine samples were chosen as proof-of-concept analytes. For the determination of phthalate metabolites in children's urine samples, high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used. Two sampling approaches were compared, namely sterile containers and baby disposable diapers. Thirty urine samples from infants and toddlers were analyzed by both methods in parallel and the results were compared. It was found that for diaper sampling, lower concentrations of the metabolites were observed, however, the general distribution for particular metabolites remains the same for both methods. For most of the metabolites high determination coefficients were obtained, namely 0.9929 for MEHHP, 0.9836 for MMP, 0.9796 for MECPP, and 0.9784 for 2-cx-MMHP. For MEOHP the determination correlation coefficient was 0.9154, while for MBP was - 0.7771 and MEHP was - 0.5228. In general, for diaper sampling an underestimation for 2-cx-MMHP and MEOHP was observed, while for MMP diaper-based approach provides overestimation. However, the proposed procedure confirms the possibility of using baby disposable diapers as a material for the collection of urine samples for biomonitoring purposes and fast screening of phthalates exposure.

Telomere length as a modifier in the relationship between phthalate metabolites exposure and glucose homeostasis

Given the rising concern over the potential impact of environmental factors on metabolic heath, we conducted a cross-sectional analysis among 645 adults aged 20 and older in the National Health and Nutrition Examination Survey (NHANES), examining the association between nine phthalate metabolites (Mono-n-butyl phthalate (MBP), Mono-ethyl phthalate (MEP), Mono-(2-ethyl)-hexyl phthalate (MEHP), Mono-benzyl phthalate (MBzP), Mono-n-methyl phthalate (MnMP), Mono-(3-carboxy propyl) phthalate (MCPP), Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), Mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), Mono-isobutyl phthalate (MiBP)) and six glucose homeostasis indices (fasting glucose, fasting insulin, hemoglobin A1C (HbA1C), homeostatic model assessment of insulin resistance (HOMA-IR), single Point Insulin Sensitivity Estimator (SPISE), and HOMA-β). Latent Class Analysis identified three phthalate metabolites exposure patterns: high MEP-low MEOHP (n = 282), high MBzP-low MEHHP (n = 214), and high MEHHP, MEOHP (n = 149). The high MBzP-low MEHHP and high MEHHP, MEOHP, versus the high MEP-low MEOHP, exposure groups showed significantly higher levels of fasting insulin (β = 0.126, 95% CI: 0.023-0.228), SPISE (β = 0.091, 95% CI: 0.018-0.164), and HOMA-IR (β = 0.091, 95% CI: 0.018-0.164). In the shorter telomere length group, high MEHHP, MEOHP exposure showed an increase in SPISE levels (β = 0.153, 95% CI: 0.037-0.269), while in the overweight/obese subgroup, high MEHHP, MEOHP exposure was significantly positively associated with HOMA-IR (β = 0.392, 95% CI: 0.150-0.735). Bayesian kernel machine regression analyses showed positive associations between higher combined phthalate exposure and increased glucose homeostasis indices (fasting glucose, HbA1C, fasting insulin, SPISE, and HOMA-IR). The quantile of g-calculation analysis also supported the positive associations with HbA1C, HOMA-IR, and fasting insulin. Our findings indicate that phthalate exposure was positively associated with glucose homeostasis indices, which strengthen the call for proactive measures to reduce phthalate exposure and mitigate potential risks to glucose metabolism.

Phthalate metabolites in breast milk from mothers in Southern China: Occurrence, temporal trends, daily intake, and risk assessment

The extensive production and use of phthalates means that these compounds are now ubiquitous in the environment and various biota, which raises concerns about potential harmful health effects. In this study, phthalate metabolites (mPAEs) were measured in breast milk (n = 100) collected from mothers of southern China between 2014 - 2022. Of the nine target mPAEs, five were detected in all of the samples, including mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP). The total levels of mPAEs in breast milk ranged from 4.76 to 51.6 ng/mL, with MiBP and MnBP being the predominant isomers (MiBP + MnBP > 48.3%). Increasing trends were observed in MMP (5.7%/year) and MEHP (7.1%/year) levels during the study period, while a decreasing trend were observed in MiBP (-6.6%/year); no clear temporal trends were found for the other metabolites and total mPAE levels. The results indicate that exposure to phthalates is still prevalent in southern China. Breastfeeding was found to contribute to estimated daily phthalate intakes of 0.383-6.95 μg/kg-bw/day, suggesting insignificant health risks to infants based on dietary exposure. However, the increasing exposure to MMP and MEHP calls for more research into the possible sources and potential risks.

Relationship between endocrine disrupting chemicals (phthalate metabolites, triclosan and bisphenols) and vitamin D in female subjects: An exploratory pilot study

INTRODUCTION

Evidence suggests that endocrine disrupting chemicals (EDCs), commonly used in plastics and personal care products, may be associated with reduced levels of vitamin D. Therefore, this study examined the relationship between phthalate metabolites, 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; TCS) and bisphenols (BPs) with vitamin D3 (25(OH)D3) and active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and their relationship to calcium homeostasis.

METHODS

57 female participants (age 31.8 ± 4.6 years; BMI 25.6 ± 3.7 kg/m2) were analyzed for urinary levels of phthalate metabolites, TCS and BPs, and serum levels of 25(OH)D3 and 1,25(OH)2D3, determined by isotope-dilution liquid chromatography tandem mass spectrometry. Serum calcium/calmodulin-dependent (CaM) associated proteins were determined by Slow Off-rate Modified Aptamer (SOMA)-scan.

RESULTS

In the study cohort, 25(OH)D3 and 1,25(OH)2D3 levels were 22.9 ± 11.2 ng/mL and 0.05 ± 0.02 ng/mL, respectively: mono-3-carboxypropyl-phthalate (MCPP) correlated negatively with 25(OH)D3 (ρ = -0.53, p = 0.01). 28 of the 57 women recruited were 25(OH)D3 deficient, <20 ng/mL (50 nmol/L): in this group, mono-iso-butylphthalate (MiBP) and mono-butylphthalate (MBP) negatively correlated with 25(OH)D3; (ρ = -0.47, p = 0.049) and (ρ = -0.64, p = 0.005), respectively. EDCs did not correlate with 1,25(OH)2D3, measures of renal function or CaM proteins.

CONCLUSION

These putative data indicate that MCPP is related to 25(OH)D3, while MiBP and MBP were related to vitamin D deficiency; however, no correlations were observed with TCS and BPs. No phthalate metabolites correlated with 1,25(OH)2D3, CaM associated proteins or renal function, suggesting that effects occur earlier in the vitamin D pathway and not through modulation of cellular calcium flux. The observed correlations are surprisingly strong compared to other predictors of 25(OH)D3, and larger studies adjusting for potential confounders are warranted.

An eco-friendly sample preparation procedure based on air-assisted liquid-liquid microextraction for the rapid determination of phthalate metabolites in urine samples by liquid chromatography-tandem mass spectrometry

Urinary phthalate metabolite (mPAEs) analysis is a reliable tool for assessing human exposure to phthalates. With growing interest in urinary biomonitoring of these metabolites, there is a need for fast and sensitive analytical methods. Therefore, a simple, rapid procedure for simultaneous determination of fifteen phthalate metabolites in human urine samples by liquid chromatography-tandem mass spectrometry was developed. The novelty of the present procedure is based on the use of diethyl carbonate as a green biobased extraction solvent and air-assisted liquid-liquid microextraction (AALLME) as a sample preparation step. A Plackett-Burman design was used for screening the factors that influence the AALLME extraction efficiency of mPAEs. The effective factors were then optimized by response surface methodology using a central composite rotatable design. Under the optimized conditions, good linearity can be achieved in a concentration range of 1.0-20.0 ng mL-1 with correlation coefficients higher than 0.99. The repeatability and reproducibility precision were in the range of 2-12% and 1-10% respectively. Recoveries ranging from 90% to 110%. This, and the low limits of detection, ranging from 0.01 to 0.05 ng mL-1, make the proposed procedure sensitive and suitable for human biomonitoring of phthalate exposures. For proof-of-principle, the new method was used to measure the urinary concentrations of mPAEs in 20 urine samples from Brazilian women. The high frequency of detections and in part high concentrations of mPAEs indicate to widespread exposure to several phthalates among Brazilian women.

Association between urinary phthalate metabolites and nephrolithiasis in adults: A cross-sectional analysis with NHANES 2007-2018

Nephrolithiasis is highly prevalent and brings health and economic burdens to patients. The augmentation of nephrolithiasis may be associated with exposure to phthalate metabolites. However, few studies investigated the effect of various phthalates exposure on nephrolithiasis. We analyzed data from 7139 participants aged 20 years or above from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. Serum calcium level-stratified univariate and multivariate linear regression analyses were performed to explore the relationship between urinary phthalate metabolites and nephrolithiasis. As a result, the prevalence of nephrolithiasis was approximately 9.96%. After adjusting for confounding factors, associations were found between serum calcium concentration with monoethyl phthalate (P = 0.012) and mono-isobutyl phthalate (P = 0.003) compared with tertile 1 (T1). In adjusted analysis, nephrolithiasis was positively associated with middle and high tertiles of mono benzyl phthalate (P < 0.05) compare with low tertile group. Furthermore, high-level exposure to mono-isobutyl phthalate had a similar positive association with nephrolithiasis (P = 0.028). Our findings provide evidence that exposure to certain phthalate metabolites (i.e. MiBP and MBzP) may be associated with a high risk of nephrolithiasis depending on serum calcium level.

Phthalates, physical activity, and diet, which are the most strongly associated with obesity? A case-control study of Chinese children

PURPOSE

Phthalate esters have been a research hotspot recently owing to potential obesogenic activity, but conflicting results have been reported. This case-control study was designed to investigate whether there was an association between phthalate metabolites and childhood obesity in China.

METHODS

A total of 240 pairs of obese/overweight children and age- (±3 months) and gender-matched controls were recruited. Nine phthalate metabolites were analyzed in the first morning urine sample. Physical activity and dietary intake were recorded using validated questionnaires.

RESULTS

In monofactor analysis, the levels of monomethyl phthalate (MMP) and monobutyl phthalate (MnBP) in controls were significantly higher than those of overweight/obese children (p < 0.05). Moderate physical activity (p = 0.004), consumption of vegetables, fruits, and tonic were significantly higher in controls (all p < 0.05), and consumption of fried food, western fast food, carbonated drinks, and juice were higher in cases (all p < 0.05). After adjusting for physical activity and dietary intake, neither MMP [OR = 0.825, (95% CI: 0.559-1.217)] nor MnBP [(OR = 0.808, 95% CI: 0.556-1.176)], were significantly associated with obesity. In all models, moderate physical activity was negatively associated and high glucose high fat dietary patterns were positively associated with the risk of childhood obesity (p < 0.01).

CONCLUSION

Diet and physical activity, but not phthalate metabolites were associated with childhood obesity. Further studies are needed to verify our findings. The trial was registered at clinicaltrials.gov as NCT05622513.

Risk assessment of phthalate metabolites accumulated in fish to the Indo-Pacific humpback dolphins from their largest habitat

Food has consistently been shown to be an important source of exposure to environmental pollutants, drawing attention to the health risks of pollutants in marine mammals with high daily food intake. Here, the dietary exposure risks posed to the Indo-Pacific humpback dolphins from the Pearl River Estuary (PRE), China, by fourteen phthalate metabolites (mPAEs) were evaluated for the first time. On the basis of liquid chromatography-mass spectrometry (LC-MS/MS) analysis, the levels of ∑₁₄mPAEs in ten main species of prey fish (n = 120) of dolphins ranged from 103.0 to 444.5 ng/g wet weight (ww), among which Bombay duck contained a significantly higher body burden of ∑₁₄mPAEs than other prey species. Phthalic acid (PA), monooctyl phthalate (MnOP), monononyl phthalate (MNP), monoethyl phthalate (MEP), monoethylhexyl phthalate (MEHP), mono (5-carboxy-2-ethylpentyl) phthalate (MECPP), monobutyl phthalate (MBP), and monoisobutyl phthalate (MiBP) all had a trophic magnification factor (TMF) greater than unity, indicating the biomagnification potential of these mPAEs in the marine ecosystem of the PRE. A dietary exposure assessment based on the adjusted reference dose values of phthalates (PAEs) showed that bis (2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) may pose a high (HQ > 1) and medium (0.01 < HQ < 1) risk to the dolphin adults and juveniles, respectively. Our results highlight the potential health risks of mPAEs to marine mammals through dietary routes.

Prenatal exposure to synthetic phenols and phthalates and child respiratory health from 2 to 36 months of life

Exposure to phthalates and synthetic phenols is ubiquitous. Some of them are suspected to impact child respiratory health, although evidence still remains insufficient. This study investigated the associations between prenatal exposure to phthalates and phenols, individually and as a mixture, and child respiratory health assessed by objective lung function measures since 2 months of age. Among 479 mother-child pairs from the SEPAGES cohort, 12 phenols, 13 phthalate and 2 non-phthalate plasticizer metabolites were measured in 2 pools including each 21 urine samples collected at the 2nd and 3rd pregnancy trimesters. Lung function was measured at 2 months using tidal breathing flow-volume loops and nitrogen multiple-breath washout, and at 3 years using oscillometry. Asthma, wheezing, bronchitis and bronchiolitis were assessed by repeated questionnaires. A cluster-based analysis was applied to identify exposure patterns to phenols and phthalates. Adjusted associations between clusters as well as each individual exposure biomarker and child respiratory health were estimated by regression models. We identified four prenatal exposure patterns: 1) low concentrations of all biomarkers (reference, n = 106), 2) low phenols-moderate phthalates (n = 162), 3) high concentrations of all biomarkers except bisphenol S (n = 109), 4) high parabens-moderate other phenols-low phthalates (n = 102). At 2 months, cluster 2 infants had lower functional residual capacity and tidal volume and higher ratio of time to peak tidal expiratory flow to expiratory time (t_PTEF/t_E) and cluster 3 had lower lung clearance index and higher t_PTEF/t_E. Clusters were not associated with respiratory health at 3 years but in the single-pollutant models, parabens were associated with increased area of the reactance curve, bronchitis (methyl, ethyl parabens) and bronchiolitis (propyl paraben). Our results suggested that prenatal exposure to mixtures of phthalates reduced lung volume in early life. Single exposure analyses suggested associations of parabens with impaired lung function and increased risk of respiratory diseases.

The cumulative risk assessment of phthalates exposure in preterm neonates

Phthalates are widely used plasticizers in various consumer products and medical devices, with some reporting as having estrogenic and anti-androgenic endocrine-disrupting effects. Premature neonates may be exposed to high levels of specific phthalates during hospitalization in the neonatal intensive care unit (NICU) because of reliance on multiple medical procedures that pose a possible health risk. The present study utilized seven urinary phthalate metabolites of dibutyl phthalate isomers [(di-n-butyl phthalate (DnBP) and diisobutyl phthalate (DiBP)], butylbenzyl phthalate (BBzP), and di(2-ethylhexyl) phthalate (DEHP) that had been previously measured in 33 preterm neonates sampled at hospital admission (N = 23) and daily during their NICU stay (N = 260). We aimed to perform: (1) cumulative risk assessment (CRA) using the volume and creatinine-adjusted models; (2) examine the temporal variability of CRA from repeated measures and (3) estimate the risk of cumulative exposure to phthalates based on their anti-androgenic and/or estrogenic properties. We multiplied the relative activity of individual phthalates exhibiting estrogenic or anti-androgenic effects by daily intake. For each preterm neonate, CRA was assessed based on the hazard index (HI) metric [the sum of hazard quotients] based on three reference doses for anti-androgenicity: the tolerable daily intake (TDI) from the European Food Safety Authority, the reference dose (RfD-AA) published in 2010 and newly revised published in 2020 (NRfD-AA). The metabolites of BBzP and DEHP were 2-23 fold higher in preterm neonates during their NICU stay. Median HIs increased in the order of HI_NRfDAA > HI_RfDAA > HI_TDI. In the creatinine-based model, 87% (92%), 87% (96%), and 100% (100%) of preterm neonates at admission (during NICU stay) showed HI_TDI, HI_RfD-AA, and HI_NRfD-AA exceeding 1, respectively with DEHP the most prevalent. The temporal reproducibility of HI (based on three reference doses) during preterm neonate stay in the NICU was high, with intra-class correlation coefficients ranging between 0.77 and 0.97, suggesting persistent exposure to phthalates. The four phthalates that preterm neonates were exposed to in the NICU exhibited estrogenic binding and anti-androgenic effects with median values (creatinine-based) of 98.7 and 56.9 μg/kg body weight/day, respectively. This was especially true for DEHP. The results indicate that preterm neonates in this NICU setting are probably at high risk of cumulative phthalate exposure with anti-androgenic properties that may have long-term adverse reproductive and developmental effects.

Association between urinary phthalate metabolites and hyperuricemia in US adults

Phthalate metabolites have been detected from urine in most of the US population and have become a public health problem. However, the association between phthalate metabolites and hyperuricemia has been scarcely studied so far. We aimed to evaluate if phthalate metabolites were associated with hyperuricemia in US adults. A total of 8816 participants of the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018 were included in our study. We used multivariable logistic regression models and restricted cubic spline (RCS) models to explore the association between urinary phthalate metabolites and hyperuricemia. Then, stratified analyses were conducted by sex and age. The prevalence of hyperuricemia in the study sample was 20.35%. Compared to the lowest quantile, the odds ratios (ORs) and 95% confidence intervals (CIs) for hyperuricemia were all statistically significant in following phthalate metabolites: 1.34 (1.13-1.58) for the second quartile in Mono-isobutyl phthalate (MiBP), 1.21 (1.01-1.46) for the highest quartile in Mono-(carboxyoctyl) phthalate (MCOP), 0.66 (0.56-0.76) for the second quartile in Mono-(2-ethyl)-hexyl phthalate (MEHP), 1.22 (1.05-1.43) for quartile 2 in Benzyl butyl phthalate (ΣBBP), and 1.43 (1.22-1.66) for the third quartile in high molecular-weight phthalate (ΣHigh MWP), respectively. Our results indicate that several urinary phthalate metabolites are positively associated with the odds of hyperuricemia.

Use of a guard column coupled to mass spectrometry as a fast semi-quantitative methodology for the determination of plasticizer metabolites in urine

For the first time, a very simple and fast method combining the use of a guard column coupled to tandem mass spectrometry (guard column-MS/MS) has been proposed for the determination of plasticizer metabolites in urine. Briefly, samples (1.0 mL) were submitted to enzymatic hydrolysis for 10 min, filtered, diluted 1/10 v/v with ultrapure water and directly injected into the system. A fast run of only 2 min (3 min including the injection cycle) allowed the determination of 19 analytes. Enzymatic hydrolysis, filtering material, and guard column-MS/MS conditions were optimized. Intra-day precision at the low-level concentration (expressed as relative standard deviation, %RSD) obtained from the analysis of synthetic urine samples varied between 11 and 20%. Limits of quantification ranged from 2.8 to 60 ng/mL. Trueness values, calculated as apparent recoveries, ranged from 70 to 135%. To correct for matrix effects, analyte concentrations in real urine were quantified by the standard addition method. To confirm the results obtained by guard column-MS/MS, an ultra(high)-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was also applied (total chromatographic run time 17 min, including column re-equilibration). Concentrations measured with both methods were in good agreement. Hence, we propose the use of guard column-MS/MS to analyse a large number samples in a very short time (semi-quantification), and apply the chromatographic analysis only to those samples with levels close to/higher than the concentrations equivalent to the safe maximum daily intakes of the parent compounds (confirmation). This double strategy (semi-quantification by guard column-MS/MS and confirmation-when needed-by UHPLC-MS/MS) implies important savings in time and money.

Influence of data acquisition modes and data analysis approaches on non-targeted analysis of phthalate metabolites in human urine

Humans are often exposed to phthalates and their alternatives, on account of their widespread use in PVC as plasticizers, which are associated with harmful human effects. While targeted biomonitoring provides quantitative information for exposure assessment, only a small portion of phthalate metabolites has been targeted. This results in a knowledge gap in human exposure to other unknown phthalate compounds and their metabolites. Although the non-targeted analysis (NTA) approach is capable of screening a broad spectrum of chemicals, there is a lack of harmonized workflow in NTA to generate reproducible data within and between different laboratories. The objective of this study was to compare two different NTA data acquisition modes, the data-dependent (DDA) and independent (DIA) acquisition (DDA), as well as two data analysis approaches, based on diagnostic ions and Compound Discoverer software for the prioritization of candidate precursors and identification of unknown compounds in human urine. Liquid chromatography coupled to high-resolution mass spectrometry was used for sample analysis. The combination of three-diagnostic-ion extraction and DDA data acquisition was able to improve data filtering and data analysis for prioritizing phthalate metabolites. With DIA, 25 molecular features were identified in human urine, while 32 molecular features were identified in the same urine samples using DDA data. The number of molecular features identified with level 1 confidence was 11 and 9 using DIA and DDA data, respectively. The study demonstrated that besides sample preparation, the impact of data acquisition must be taken into account when developing a NTA method and a consistent protocol for evaluating such an impact is necessary.

Application of growth modeling to assess the impact of hospital-based phthalate exposure on preterm infant growth parameters during the neonatal intensive care unit hospitalization

In this study, we use advanced growth modeling techniques and the rich biospecimen and data repositories of the NICU Hospital Exposures and Long-Term Health (NICU-HEALTH) study to assess the impact of NICU-based phthalate exposure on extrauterine growth trajectories between birth and NICU discharge. Repeated holdout weighed quantile sum (WQS) regression was used to assess the effect of phthalate mixtures on the latency to first growth spurt and on the rate of first growth spurt. Further, we assessed sex as an effect modifier of the relationship between a phthalate mixture and both outcomes. Nine phthalate metabolites, mono-ethyl phthalate (MEP), mono-benzyl phthalate (MBzP), mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-(3-carboxypropyl) phthalate (MCPP), mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) were measured in weekly urine specimens from 101 NICU-HEALTH participants between birth and the first growth spurt. Phthalate levels varied by species but not by infant sex, and decreased over the course of the NICU hospitalization as presented in detail in Stroustrup et al., 2018. There was evidence of nonlinearity when assessing the effect of phthalates on latency to first growth spurt. Above a threshold level, a higher phthalate mixture with dominant contributors MCPP, MBzP, and MEP predicted a shorter latency to the first inflection point, or an earlier growth spurt. A higher phthalate mixture with dominant contributors MECPP, MEHHP, and MEOHP was associated with an increased rate of growth. Results of both models were clearly different for boys and girls, consistent with other studies showing the sexually dimorphic impact of early life phthalate exposure. These results suggest that growth curve modeling facilitates evaluation of discrete periods of rapid growth during the NICU hospitalization and exposure to specific phthalates during the NICU hospitalization may both alter the timing of the first growth spurt and result in more rapid growth in a sexually dimorphic manner.

Urinary phthalate metabolites and their mixtures are associated with advanced sperm epigenetic aging in a general population

INTRODUCTION

We have recently shown that sperm epigenetic age (SEA), a surrogate measure of biological aging in sperm, is associated with couples' time-to-pregnancy (TTP). Advanced SEA was also observed among smokers, suggesting its susceptibility to environmental exposures. Therefore, we assessed the association between urinary phthalate metabolites and SEA in male partners of couples planning to conceive among the general population.

METHOD

The Longitudinal Investigation of Fertility and the Environment (LIFE) Study was a prospective multi-site and general population cohort study of couples who were interested in becoming pregnant. Among male partners (n = 333), eleven urinary phthalate metabolites were measured and SEA was previously developed using Super Learner ensemble algorithm. Multivariable linear regression was used to evaluate associations of SEA with individual metabolites. Bayesian kernel machine regression (BKMR), quantile g-computation (qgcomp) and weighted quantile sum (WQS) models were used for mixture analyses. Covariates included were BMI, cotinine, race and urinary creatinine.

RESULT

In the single metabolite multivariate analyses, nine (82%) phthalate metabolites displayed positive trends with SEA (range: 0.05-0.47 years). Of these metabolites, advanced SEA was significantly associated with interquartile range increases in exposure of three phthalates [MEHHP (β = 0.23, 95% CI: 0.03, 0.43, p = 0.03), MMP (β = 0.24, 95% CI: 0.01, 0.47, p = 0.04), and MiBP (β = 0.47, 95% CI: 0.14, 0.81, p = 0.01)]. Additionally, in BKMR and qgcomp (p = 0.06), but not WQS models, phthalate mixtures showed an overall positive trend with SEA, with MiBP, MMP and MBzP as major drivers of the mixture effects.

CONCLUSION

This is the first study that combined single exposure and mixture models to associate male phthalate exposures with advanced epigenetic aging of sperm in men planning to conceive among the general population. Our findings suggest that phthalate exposure may contribute to the acceleration of biological aging of sperm.

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.

Association of urinary phthalate metabolites with renal function among 9989 US adults

PURPOSE

This study aimed to investigate the relationship between phthalate metabolites and renal function.

METHODS

We analyzed data from 9989 participants who took part in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Renal function was reflected by estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (UACR), and hypertension. We used generalized linear regression to estimate the correlation between covariate-adjusted creatinine-normalized phthalate metabolites and renal function. In addition, subgroup analysis was used to further compare the effect differences between various populations.

RESULTS

In the adjusted model, we found differential associations between phthalates and plasticizers metabolites and renal function. We found that Mono-benzyl phthalate, Mono-(3-carboxypropyl) phthalate, and Mono-(2-ethyl-5-oxohexyl) phthalate were positively associated with lower eGFR with odds ratios (95% confidence intervals) of 1.38 (1.14, 1.67), 1.30 (1.09, 1.57), and 1.27 (1.04, 1.53). While Mono-ethyl phthalate, Mono-(2-ethyl)-hexyl phthalate, Mono-isononyl phthalate and Mono-isobutyl phthalate were negatively associated with lower eGFR with OR values of 0.79 (0.69, 0.90), 0.64 (0.52, 0.78), 0.65 (0.51, 0.82) and 0.80 (0.63, 1.00), respectively. In addition, we found that Mono(carboxyoctyl) phthalate and Mono-isobutyl phthalate were negatively associated with hypertension with ORs of 0.86 (0.78, 0.96) and 0.84 (0.72, 0.98). But phthalates and plasticizers metabolites were not associated with UACR.

CONCLUSION

This study found differences in the effects of phthalates and plasticizers metabolites on kidney function, which may raise concerns about possible changes in kidney function resulting from exposure to current levels of plasticizers.

Levels and health risks of urinary phthalate metabolites and the association between phthalate exposure and unexplained recurrent spontaneous abortion: a large case-control study from China

Phthalate acid esters (PAEs) are environmental endocrine disruptors that can interfere with endocrine processes and cause adverse reproductive outcomes. The link between PAE exposure and unexplained recurrent spontaneous abortion (URSA) remains unknown. In this study, nine urinary metabolites of PAEs (mPAEs) were measured in 594 URSA cases and 569 healthy controls. The measured mPAEs were ubiquitously detected and present at higher levels (median: 203 ng/mL) in the URSA cases than in the controls (median: 161 ng/mL). Multiple logistic regression analysis showed that URSA was associated with higher concentrations of mono (2-ethyl-5-hydroxyhexyl) phthalate (mEHHP), mono (2-ethylhexyl) phthalate (mEHP), and mono-ethyl phthalate (mEP) and lower concentrations of mono-isobutyl phthalate (miBP). Moreover, a quantile-based g-computation (QGC) model revealed a positive association between mPAEs mixture and URSA. The URSA cases showed significantly higher concentrations of di-(2-ethylhexyl) phthalate (DEHP) than the controls. This was consistent with the health risk assessment, which suggested that DEHP is the main contributors to potential non-carcinogenic risk. DEHP accounted for over 80% of total risk. The large case-control study results suggest that PAE exposure may increase the risk of URSA, and that policy-makers and public health experts should pay more attention to DEHP exposure.

Phthalate metabolites in paired human serum and whole blood

Presence of phthalate metabolites (PMs) in human serum has been well documented. However, the distribution pattern of PMs in different human blood matrixes remains not well known. To investigate this, paired serum and whole blood samples were collected from 145 adults (76 males and 69 females) in Quzhou, China, and analyzed for nine PMs in this study. All PMs had high detection frequencies (> 70%) in human serum and whole blood, except mono benzyl phthalate. Total concentrations of detected PMs in serum and whole blood were 0.70-61 ng/mL (mean 12 ng/mL) and 1.6-33 ng/mL (7.5 ng/mL), respectively. Mono methyl phthalate (MMP), mono (2-ethylhexyl) phthalate, and mono butyl phthalate were consistently the predominant PMs in human serum and whole blood, with the mean concentrations of 3.4 and 2.0 ng/mL, 3.3 and 2.1 ng/mL, and 2.8 and 1.8 ng/mL, respectively. Females had higher mean serum concentrations of PMs, except MBP, than males. Youngest age group (20-30 years) consistently had the lowest mean whole blood levels of all PMs. For the first time, the distribution pattern of PMs in human blood was evaluated based on the calculated partitioning coefficient (K_p) between serum and whole blood. MMP had the highest mean K_p value (1.6; 10th-90th percentile: 1.0-2.2), while mono (2-ethyl-5-oxohexyl) phthalate had the lowest mean K_p value (0.63; 10th-90th percentile: 0.25-1.3). These results help better understand the occurrence of PMs in human blood.

Prenatal phthalate exposure measurement: A comparison of metabolites quantified in prenatal maternal urine and newborn's meconium

Phthalates are chemicals suspected to adversely affect fetal neurodevelopment, but quantifying the fetal exposure is challenging. While prenatal phthalate exposure is commonly quantified in maternal urine, the newborn's meconium may better capture cumulative prenatal exposure. Currently, data on phthalates measured in meconium is sparse. We measured phthalate metabolites in 183 maternal second and 140 third trimester (T2, T3) urine, and in 190 meconium samples collected in an autism enriched-risk pregnancy cohort of 236 mothers. Eleven and eight metabolites were detected in over 90% of urine and meconium samples, respectively. Hydrophilic and hydrophobic metabolites were detected in both biosamples. Most urine phthalate metabolite distributions were similar between T2 and T3. Among metabolites detected in both biosamples, those of di(2-ethylhexyl) phthalate displayed a similar pattern in magnitude across metabolite type. Specifically, T2 creatinine adjusted distribution [median (25%, 75%)] of urine measured mono(2-ethylhexyl-carboxypentyl) (MECPP), mono(2-ethyl-5-hydroxyhexyl) (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) were 18.8(11.9, 31.4), 11.8(7.2, 19.1), and 8.9(6.2, 14.2) ng/mg. In meconium these were 16.6(10.9, 23.7), 2.5(1.5, 3.8), and 1.3(0.8, 2.3) ng/g, respectively. Metabolite-to-metabolite correlations were lower in meconium than urine, but patterns were similar. For example, correlation (95% CI) between mono(2-ethylhexyl) phthalate and MECPP was 0.73 (0.66, 0.78), and between MEOHP and MEHHP was 0.96 (0.95, 0.97) in urine as compared to 0.10 (-0.04, 0.24) and 0.31 (0.18, 0.43) respectively in meconium. Correlations between same metabolites measured in urine and meconium were low and differed by metabolite and trimester. Correlation between MEHHP in urine and meconium, for example, was 0.20 (0.008, 0.37) at T3, but 0.05 (-0.12, 0.21) at T2. Our study provides evidence of general population-level prenatal phthalate exposure in a population at high risk for neurodevelopmental disorders and supports the utility of meconium to measure prenatal phthalate exposure but provides little evidence of correlation with exposure measured in prenatal maternal urine.

The exposure levels of phthalates in pregnant women and impact factors of fetal malformation

METHODS

Urine samples were collected from 157 women with fetal malformations (case group) and 147 women with normal fetuses (control group). High-performance liquid chromatography-mass spectrometry (HPLC-MS) was used to detect the content of eight metabolites of phthalate compounds in urine, including monoethyl phthalate (MEP), mononbutyl phthalate (MBP), monoisobutyl phthalate (MiBP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-benzyl phthalate (MBzP). Demographic data were collected from questionnaires administered in specimen collection.

RESULTS

The exposure level of MEOHP and MEHP in the case group was higher than the others. And there were significant differences between structural malformations and chromosomal malformations in the levels of MEHHP and MEOHP. Pregnant women with low income, high body mass index (BMI), frequent plastic contact, and low nutrients intake were at risk of suffering from fetal malformation.

CONCLUSION

This study provides evidence for the correlation between the concentration of phthalates and fetal malformation. In addition, decreasing plastic exposure and supplementing nutrients may reduce the incidence of fetal malformations.

Human biomonitoring reference values and characteristics of Phthalate exposure in the general population of Taiwan: Taiwan Environmental Survey for Toxicants 2013-2016

Since a 2011 incident involving phthalate-tainted food, Taiwanese people have become concerned with food quality, and they are still being exposed to certain levels of phthalates. However, no nationwide human biomonitoring survey had been conducted to gather information on levels or reference values (RVs) of phthalates in the Taiwanese population. We aimed to establish the urinary levels and RVs of phthalate metabolites and identify exposure characteristics among Taiwan's population. We enrolled 1857 participants 7 years of age and older from the Taiwan Environmental Survey for Toxicants (TESTs) conducted during 2013-2016. Levels of 11 phthalate metabolites in each participant's urine samples were determined using liquid chromatography-tandem mass spectrometry. For all phthalate metabolites except for mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), and mono-ethylhexyl phthalate (MEHP), urinary median levels were significantly higher in the 7-17-year old group than in the ≧18-year-old group. For most phthalate metabolites and in the general population, the geometric mean decreased with increasing age. Median levels of MEP (19.55 μg/L), mono-benzyl phthalate (MBzP) (2.11 μg/L), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (22.82 μg/L), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEOHP) (16.08 μg/L), ΣDibutyl phthalate metabolites (ΣDBPm) (0.17 nmol/mL), Σdi-(2-ethylhexyl) phthalate metabolites (ΣDEHPm) (0.29 nmol/mL) were higher in participants from central Taiwan than those from other areas. The median level of DBP (ΣDBPm: 0.20 nmol/mL) was significantly higher in participants from harbor areas than those from other urbanization groups. The RV of the 95 percentile (P₉₅) for phthalate metabolites in the 7-17/≧18-year-old groups were 185.95/208.19 μg/L for MMP, 198.46/265.81 μg/L for MEP, 119.85/69.99 μg/L for mono-isononyl phthalate (MiBP), 165.19/204.32 μg/L for Mono-n-butyl phthalate (MnBP), 15.61/11.73 μg/L for MBzP, 62.09/59.23 μg/L for MEHP, 149.70/69.66 μg/L for MEHHP, 112.06/35.07 μg/L for MEOHP, 195.20/93.83 μg/L for mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), 45.66/27.69 μg/L for mono-(2-carboxymethylhexyl) phthalate (MCMHP), and 9.09/12.13 μg/L for mono-iso-nonyl phthalate (MiNP). We concluded that phthalate exposure of the general population in Taiwan varies by sex, age, region, and urbanization level. Exposure by the 7-17-year-old group to DMP, DBP, and DEHP in Taiwan remains higher than that of youth from other countries. RV of phthalate metabolites in Taiwan were established in the current study.

Potential health risks of maternal phthalate exposure during the first trimester - The Saudi Early Autism and Environment Study (SEAES)

Phthalates are the most ubiquitous contaminants that we are exposed to daily due to their wide use as plasticizers in various consumer products. A few studies have suggested that in utero exposure to phthalates can disturb fetal growth and development in humans, because phthalates can interfere with endocrine function. We collected spot urine samples from 291 pregnant women in their first trimester (9.8 ± 2.3 gestational weeks) recruited in an ongoing prospective cohort study in Saudi Arabia. A second urine sample was collected within 1-7 d after enrollment. The aims of this study were to: (1) assess the extent of exposure to phthalates during the first trimester and (2) estimate the risk from single and cumulative exposures to phthalates. Most phthalate metabolites' urinary levels were high, several-fold higher than those reported in relevant studies from other countries. The highest median levels of monoethyl phthalate, mono-n-butyl phthalate (MnBP), mono-iso-butyl phthalate (MiBP), and mono-(2-ethylhexyl) phthalate (MEHP) in μg/l (μg/g creatinine) were 245.62 (197.23), 114.26 (99.45), 39.59 (34.02), and 23.51 (19.92), respectively. The MEHP levels were highest among three di (2-ethylhexyl) phthalate (DEHP) metabolites. %MEHP₄, the ratio of MEHP to four di (2-ethylhexyl) phthalate metabolites (∑₄DEHP), was 44%, indicating interindividual differences in metabolism and excretion. The hazard quotient (HQ) of individual phthalates estimated based on the reference dose (RfD) of the U.S. Environmental Protection Agency indicated that 58% (volume-based) and 37% (creatinine-based) of the women were at risk of exposure to ∑₄DEHP (HQ > 1). Based on the tolerable daily intake (TDI) from the European Food Safety Authority, 35/12% (volume-/creatinine-based data) of the women were at risk of exposure to two dibutyl phthalate (∑DBP) metabolites (MiBP and MnBP). The cumulative risk was assessed using the hazard index (HI), the sum of HQs of all phthalates. The percentages of women (volume-/creatinine-based data) at health risks with an HI > 1 were 64/40% and 42/22% based on RfD and TDI, respectively. In view of these indices for assessing risk, our results for the anti-androgenic effects of exposing pregnant women to ∑₄DEHP and ∑DBP early during pregnancy are alarming.

Association of urinary phthalate metabolites with osteoarthritis in American adults: Results from the national health and nutrition examination survey 2003-2014

Phthalates have extensive existence in the living environment of human, probably tightly associated with multiple human diseases. The present study aimed to exploratorily investigate the association of urinary phthalate metabolites with osteoarthritis (OA) in American adults by exploiting the data extracted from National Health and Nutrition Examination Survey (NHANES) 2003-2014 with levels of eleven urinary phthalate metabolites as exposure. The multivariable logistic regression models were performed after controlling for urinary creatinine, age, gender, race/ethnicity, education level, marital status, smoking, body mass index, physical activity in recreational time, family poverty income ratio, diabetes, hypertension, as well as survey cycle. Compared with those in the lowest quantile, we observed higher prevalence of OA in the maximal quantile of MCOP (OR = 1.55, 95% CI = 1.06-2.27) in adjusted model. A one-unit increase in log-transformed phthalate metabolites was significantly associated with higher OA prevalence, including MCOP (OR = 1.13, 95% CI = 1.02-1.26) and MBzP (OR = 1.12, 95% CI = 1.00-1.26) in adjusted model. In subgroup analysis, the positive associations between phthalate metabolites and OA prevalence remained robust both in males and females. In brief, this study first presented positive evidence for the association of urinary level of phthalate metabolites with OA prevalence in American adults. Additional causal research is required to confirm the finding from our analysis and elucidate the potential underlying mechanisms of phthalates exposure on OA.

The influence of prenatal exposure to phthalates on subsequent male growth and body composition in adolescence

Phthalates are ubiquitous environmental chemicals with predominantly anti-androgenic, and potentially obesogenic effects. We hypothesised that antenatal phthalate exposure may influence subsequent boy's growth and body composition through childhood and adolescence. Among 1399 singleton males from the Raine Study, 410 had maternal serum and at least one height, BMI or DEXA outcome available after birth and up to 20 years of age. Maternal serum collected at 18 and 34 weeks' gestation was pooled, and analyzed for concentrations of 32 metabolites of 15 phthalate diesters. Their serum concentrations were categorized into undetectable/detectable levels or tertiles. Linear mixed models were used to determine associations between maternal serum phthalate levels and longitudinal height and body mass index (BMI) z-scores in boys from birth to 20 years of age (n = 250 and n = 295 respectively). Linear regression was used to determine associations between maternal phthalate levels and deviation from mid-parental height (n = 177) and DEXA scan outcomes (n = 191) at the 20 year follow-up. Weak positive associations of participants height z-score increase were detected with exposure to some phthalate metabolites in particular to the lower molecular weight phthalate metabolites. Less consistent findings, by mixed model analyses, were detected for BMI and body composition, by dual energy X-ray absorptiometry (DEXA), with some positive associations of phthalate metabolites with BMI and some negative associations with DEXA fat tissue measures, although no consistent findings were evident. In conclusion, we derived some associations of childhood growth with prenatal phthalate exposure, particularly with respect to the lower molecular weight phthalate metabolites.

Levels and determinants of urinary phthalate metabolites in Chinese community-dwelling older adults

BACKGROUND

Biomonitoring studies have demonstrated extensive exposure of infants, children, and pregnant women to phthalates, but data on phthalate exposure and their determinants in Chinese older adults remain insufficient. This study aims to assess urinary phthalate metabolite levels, individual and cumulative exposure risk, and their determinants in Chinese community-dwelling older adults.

METHODS

A total of 987 individuals aged 60 years or over were included in this study. The urinary levels of seven phthalate metabolites were measured using high-performance liquid chromatography-tandem mass spectrometry. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) of phthalates were calculated based on urinary metabolite levels. The associations between phthalate metabolite levels and potential determinants were examined using multiple linear regressions.

RESULTS

Detection rates of seven phthalate metabolites from the study population ranged from 63.83% to 99.39%. The highest median concentration was 43.64 μg/L (42.59 μg/g creatinine) for mono-butyl phthalate (MBP). The highest median EDI was 1.55 μg/kg-bw/day for diethyl phthalate (DBP). Nearly 5% of participants had high HI values exceeding 1, mainly attributed to DBP and di-2-ethylhexyl phthalate (DEHP). Furthermore, we found that females, higher body mass index (BMI), smoking, having two or more chronic diseases, and vegetable-based diets were significantly associated with higher levels of parts of phthalate metabolites. More interestingly, higher urine levels of high-molecular-weight (HMW) phthalate metabolites and lower urine levels of low-molecular-weight (LMW) phthalate metabolites were found in rural older adults than in urban older adults.

CONCLUSIONS

Chinese community-dwelling older adults are extensively exposed to phthalates, especially to DBP and DEHP. More attention should be paid to urban-rural differences in exposure to HMW and LMW phthalates and to phthalate exposure among older adults with overweight/obesity, females, and individuals who are current heavy smokers, have two or more chronic diseases, and consume vegetable-based diets.

The internal exposure of phthalate metabolites and bisphenols in waste incineration plant workers and the associated health risks

Many hazardous substances can be released during incineration of municipal solid waste (MSW), which pose a potential threat to human health. As additives, phthalates (PAEs) and bisphenols (BPs), which are widely used in daily goods, are likely to be present in the released hazardous substances. In the present study, we investigated the urinary levels of phthalate metabolites (mPAEs) and BPs in workers in an MSW incineration plant (the exposed group) and in residents 8 km away (the control group) in Shenzhen, China. The results showed that the median total urinary concentration of mPAEs in workers was significantly higher than that in residents (1.02 × 10³ vs. 375 ng/mL). However, there was no significant difference between workers and residents for BPs. Among the mPAEs measured, the most abundant compound was mono-n-butyl phthalate in both exposed and control groups. Monoethyl phthalate and monomethyl phthalate might be potential markers for MSW incineration because of significantly high levels in the exposed group. The workers engaged in different types of workshops showed no significant differences in the urinary levels of mPAEs, also for BPs. It was worth noting that 70.8% of workers were at risk of the non-carcinogenic effects caused by PAEs with diethylhexyl phthalate having the highest risk. Actions should be taken to reduce the risks caused by these hazardous chemicals.

Prediction of liquid chromatographic retention time using quantitative structure-retention relationships to assist non-targeted identification of unknown metabolites of phthalates in human urine with high-resolution mass spectrometry

The non-targeted analysis and identification of contaminant metabolites such as metabolites of phthalates and their alternatives in human biofluid samples constitutes a growing research field in human biomonitoring because of their importance as biomarkers of human exposure to the parent compounds. High-resolution mass spectrometry (HRMS) combined with high-performance liquid chromatography (HPLC) can provide fast separation and sensitive analysis using this application. However, the diversity of potential metabolites, especially isomers, in human samples, makes mass spectrometry-based structural identification very challenging, even with high-resolution and accurate mass. In this study, we present a retention time (t_R) prediction model based on quantitative structure-retention relationship (QSRR). This model can predict the retention time of a given structure of phthalates including isomers. Twenty-three molecular descriptors were used in the development of the multivariate linear regression QSRR model. The regression coefficient (R²) between predicted and experimental retention times of 26 training set compounds was 0.9912. The combination of the retention time prediction model with identification via accurate mass search and target MS/MS spectrum interpretation can enhance the identification confidence in the lack of reference standards. Two previously unreported phthalate metabolites were identified in human urine, using this model. The results of this study showed that the developed QSRR model could be a useful tool to predict the retention times of unknown metabolites of phthalates and their alternatives in future non-targeted screening analysis. The concentration of these two unknown compounds was also estimated using a quantitative structure-ion intensity relationship (QSIIR) model.

Phthalate exposure linked to high blood pressure in Chinese children

BACKGROUND

Exposure to phthalate esters may be linked to the risk of high blood pressure (HBP), but limited evidence is available in Chinese children.

OBJECTIVE

To investigate the associations between nine phthalate metabolites (mPAEs) and systolic/diastolic BP, pulse pressure (PP), mean arterial pressure (MAP), and the risk of HBP.

METHODS

In this cross-sectional study, a total of 1044 primary school children (6-8 years old) were enrolled from Shenzhen, China, between 2016 and 2017. Nine mPAEs were analyzed from urine using ultra-performance liquid chromatography and tandem mass spectrometry. A multivariable linear regression model was used to explore the associations between phthalate exposure and systolic/diastolic BP, PP, and MAP. A binary logistic regression model was used to examine the associations between phthalate exposure and the risk of HBP.

RESULTS

Monomethyl phthalate (MMP) concentrations were significantly higher in HBP children than normal BP children. MMP, monoisobutyl phthalate (MiBP), monobutyl phthalate (MnBP), mono(5-carboxy-2-ethylpentyl) phthalate, mono-[(2-carboxy methyl)hexyl] phthalate (MCMHP), the sum of four short-chain mPAEs (∑LMW), and the sum of all nine mPAEs (∑₉mPAEs) were significantly positively associated with increases in systolic BP z-score, while only MMP was significantly positively associated with diastolic BP z-score. MMP, MiBP, MnBP, MCMHP, ∑LMW, and ∑₉mPAEs were significantly associated with increases in PP, while MMP and MnBP were significantly associated with increases in MAP. MMP was significantly associated with the risk of HBP, with an odds ratio of 1.87 (95% CI: 1.23, 2.85).

CONCLUSIONS

The present study suggests that dimethyl phthalate exposure increases the risk of HBP. And some types of phthalates are associated with elevations in systolic/diastolic BP z scores, PP, and MAP in Chinese children.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

[A study on the correlation of phthalate metabolites in umbilical cord blood of 161 newborns with birth indicators in Beijing]

Objective: To analyze the correlation of phthalate metabolites in neonatal umbilical cord blood with birth indicators in Beijing, 2015. Method: From February to July in 2015, 161 pregnant women and their newborns who met the criteria were recruited from the Maternal and Child Health Hospital in Haidian District, Beijing. Questionnaires were used to collect the demographic information of pregnant women such as age, smoking, drinking, and cord blood after delivery. An ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine the concentration of phthalate metabolites in umbilical cord blood. The multiple linear regression model was used to analyze the correlation of phthalate metabolites in umbilical cord blood with the neonatal weight, length, and ponderal index. Result: The age of 161 pregnant women was (30.3±3.0) years. The weight, length and ponderal index of 161 newborns were (3 447.2±413.0) kg, (50.2±1.1) cm, and (26.7±2.2) kg/m³; 51.6% of newborns (83 cases) were boys. The concentrations of seven phthalate metabolites detected in umbilical cord blood, i.e., mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP),mono-(2-isobutyl) phthalate (MiBP), mono-n-butyl phthalate (MBP), mono-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), was (3.50±0.28), (2.65±0.47), (4.31±0.55), (6.26±0.57), (1.71±0.13), (1.10±0.09) and (0.47±0.06) ng/ml, respectively. The result of multiple linear regression model analysis showed that the concentrations of seven phthalate metabolites were not related to the neonatal weight, length, and ponderal index (all P values> 0.05). Conclusion: The concentrations of phthalate metabolites in neonatal umbilical cord blood are low, and they are not related to the neonatal weight, length, and ponderal index.

Characterization of phthalate exposure in relation to serum thyroid and growth hormones, and estimated daily intake levels in children exposed to phthalate-tainted products: A longitudinal cohort study

BACKGROUND

No information is available on the long-term effects on thyroid and growth hormones of children exposed to phthalate-tainted products, despite the infamous 2011 Taiwan phthalate episode. We investigated estimated daily intake levels and their long-term effects on serum thyroid and growth hormone levels in children.

METHODS

We recruited 166 children (2-18 years old) in three visits who provided specimens and filled out a questionnaire from the Risk Assessment of Phthalate Incident in Taiwan (RAPIT) project study from 2012 to 2016. Morning spot urine samples were analyzed for nine phthalate metabolites. Serum thyroid (triiodothyronine [T₃], thyroxine [T₄], and free T₄) and growth hormone (insulin-like growth factor-1 [IGF-1] and its binding protein 3 [IGF-BP3]) levels were measured. A generalized estimating equation model was used to evaluate associations between phthalate metabolite levels and children's thyroid and growth hormone levels.

RESULTS

The median metabolite levels of monomethyl phthalate (MMP), Σdibutyl phthalate (DBP), and Σdi-(2-ethylhexyl) phthalate (DEHP) at visits 1, 2, and 3 were 6.59, 10.5, and 21.0 ng/mL, 0.15, 0.24, and 0.20 nmol/mL, and 0.15, 0.17, and 0.12 nmol/mL, respectively. After adjusting for potential confounding factors, we found that levels of urinary MMP were negatively associated with T₃ (β = -0.013, p = 0.047), T₄ (β = -0.016, p = 0.006), free T₄ (β = -0.012, p = 0.002), and IGF-BP3 (β = -0.025, p = 0.003). Urinary mono-ethyl phthalate (MEP) was negatively associated with IGF-1 (β = -0.027, p = 0.029) and IGF-BP3 (β = -0.016, p = 0.018). In addition, serum free T₄ was positively associated with urinary mono-2-ethyl-5-hydroxy hexyl phthalate (MEHHP) (β = 0.016, p = 0.043), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 0.015, p = 0.024), and ΣDEHPm (β = 0.019, p = 0.020).

CONCLUSIONS

Our findings support the hypothesis that specific phthalates disturb the hemostasis of thyroid and growth hormone levels in children exposed to phthalate-tainted products.

conjugated-form concentration

In previous studies, the total content of urinary phthalate metabolites was commonly used to evaluate human exposure to phthalates. However, phthalate metabolites are mainly present in urine in two forms, conjugated and free. These metabolite forms in urine are more relevant to the biotransformation pathways of the phthalates in humans. Therefore, the concentration of these forms is more relevant to exposure related health outcomes than total content. In this study, instead of measuring total content, the free- and conjugated-form concentrations of phthalate metabolites in the urine of fertile and infertile men were measured. The main metabolites in urine of both groups are monoethyl phthalate (MEP) and the di-(2-ethylhexyl) phthalate (DEHP) metabolites. The geometric means of their both conjugated- and free-forms in the infertile group were higher than in the fertile group, specifically, 24.3 and 43.4 μg/g creatinine vs 8.5 and 28.9 μg/g creatinine, respectively, for MEP, and 50.0 and 9.1 μg/g creatinine vs 39.1 and 8.4 μg/g creatinine, respectively for total DEHP metabolites. We investigated the correlations of free- and conjugated-form phthalate metabolite concentrations between the infertile and fertile group as well as among different phthalate metabolites. The results showed that there was a statistically significant difference between the infertile and fertile group for monobenzyl phthalate (MBzP) in both free-form and conjugated-form. However, there was only a statistically significant difference between the two groups for conjugated-form MEP and MEHP, and no statistically significant difference between the two groups for free-form MEP and MEHP. The results of the Pearson correlation test revealed that the correlations between DEHP metabolites and the correlations between mid-sized phthalate metabolites (mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP) and mono-benzyl phthalate (MBzP)) were stronger than between these two clusters of metabolites. This study is the first attempt to examine possible effects of conjugated-form concentrations of phthalate metabolites on human fertility. The results of this study suggest that conjugated-form and free-form concentrations of urinary phthalate metabolites may be appropriate biomarkers for assessing human exposure to phthalates and association with health outcomes.

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.

Phthalate metabolites concentrations in amniotic fluid and maternal urine: Cumulative exposure and risk assessment

Phthalates are used in industry as plasticizers or additives in everyday products and they have been considered as endocrine disrupting chemicals. Maternal exposure during pregnancy has been associated with neonatal exposure, preterm birth and impacts in the reproductive and respiratory systems. The aim of this study is to determine six phthalate metabolites (mono isobutyl phthalate, miBP, mono n-butyl phthalate, mnBP, mono benzyl phthalate, mBzP, mono ethylhexyl phthalate, mEHP, mono 2-ethyl-5-hydroxyhexyl phthalate, mEHHP, mono 2-ethyl-5-oxohexyl-phthalate, mEOHP) in amniotic fluid and urine from 100 pregnant women. Participants answered questionnaires for the use of plastics and cosmetics, dietary habits, health effects, pregnancy problems, health and infant development. Positive amniotic fluid samples ranged from 1% to 21% and urine from 27% to 54%. The median levels for amniotic fluid were 2.3 μg/L - 10.7 μg/L and for urine 4.9 μg/L - 46.7 μg/L. The major results include significant correlations between urinary phthalates indicating their common sources of exposure, the frequent use of deodorant was significantly associated with higher urinary miBP (p = 0.050) and mnBP (p = 0.028) and a weak inverse association was found for the use of make-up products with mBzP (p = 0.053). The frequent use of plastic food containers was significantly associated with urinary mEHP (p = 0.026), and a positive trend was noticed for mEHP in amniotic fluid (p = 0.093). An association although weak was found between urinary mEHP and lower birth length (rs = 0.396, p = 0.062). No other associations were found for infant health problems or development. The daily intake of the total phthalates was calculated 5.4 μg/kg body weight/day which corresponds to hazard index 0.10 and exposure follows the declining trend that has been observed the last decades.

Biomonitoring of bisphenols A and S and phthalate metabolites in hair from pregnant women in Crete

Phthalates, bisphenols A and S (BPA, BPS) are used as plasticizers and many of them are documented or suspected of being endocrine disruptors. Several studies indicate that exposure during pregnancy may affect the newborn's health and development. The aim of this cross-sectional study is the biomonitoring of seven phthalate metabolites, BPA and BPS in hair from 100 pregnant women in Crete. The most frequently detected compounds were monoethylhexyl phthalate (mEHP) (68%), mono isobutyl phthalate (miBP) (40%), BPA (37%), BPS (34%) and mono-n-butyl phthalate (mnBP) (28%). Phthalate metabolites were detected at medians from 19.5 to 44.4 pg/mg, BPA at 69.9 pg/mg and BPS at 3.5 pg/mg. Significant positive correlations between phthalate metabolites were found which indicated their common sources of exposure. The frequent use of plastics for food storage was strongly associated with mEHP (p = .013) and a weaker association was found for miBP (p = .063). The frequent use of cosmetics during or before pregnancy was associated with levels of phthalate metabolites in hair. More specifically, the use of hair spray before pregnancy was significantly correlated with monobenzyl phthalate (mBzP) (p = .041) and a trend was found for miBP (p = .066). The use of makeup products during pregnancy was strongly associated with miBP (p = .015) and the use of deodorant during pregnancy was inversely associated with mEHP (p = .021). Strong associations came up between mEHP and lower birth weight (Spearman correlation coefficient, r = -0.302, p = .021) and exposure to BPS was associated with increased body mass index of the participants (p = .036). Although data in literature on biomonitoring of the compounds in hair are limited, the findings of this study are promising and in agreement with existing data in hair or urine.

Phthalate metabolites in harbor porpoises (Phocoena phocoena) from Norwegian coastal waters

The exposure of marine mammals to phthalates has received considerable attention due to the ubiquitous occurrence of these pollutants in the marine environment and their potential adverse health effects. The occurrence of phthalate metabolites is well established in human populations, but data is scarce for marine mammals. In this study, concentrations of 17 phthalate metabolites were determined in liver samples collected from one hundred (n = 100) by-caught harbor porpoises (Phocoena phocoena) along the coast of Norway. Overall, thirteen phthalate metabolites were detected in the samples. Monoethyl phthalate (mEP), mono-iso-butyl phthalate (mIBP), mono-n-butyl phthalate (mBP) and phthalic acid (PA) were the most abundant metabolites, accounting for detection rates ≥ 85%. The highest median concentrations were found for mIBP (30.6 ng/g wet weight [w.w.]) and mBP (25.2 ng/g w.w.) followed by PA (7.75 ng/g w.w.) and mEP (5.67 ng/g w.w.). The sum of the median phthalate metabolites concentrations that were found in the majority of samples (detection rates > 50%) indicated that concentrations were lower for porpoises collected along the coastal area of Bodø (Nordland), Lebesby (Finnmark) and Varangerfjord (as compared to other coastal areas); these areas are among the least populated coastal areas but also the most distant (>700 km) from offshore active oil and gas fields. The monomethyl phthalate metabolite (mMP) was detected in 69% of the samples, and to our knowledge, alongside with PA, this is the first report of their occurrence in marine mammals. PA, as the non-specific marker of phthalate exposures, showed a statistically significant negative association with the body mass and length of the harbor porpoises. Among the phthalate metabolites, statistically significant positive associations were found between mBP and mIBP, mMP and mEP, PA and mEP, mIBP and mono(2-ethyl-5-oxohexyl) phthalate (mEOHP), mIBP and mono(2-ethyl-5-hydroxyhexyl) phthalate (mEHHP), mBP and mEHHP, mono-n-nonyl phthalate (mNP) and PA, and between monobenzyl phthalate (mBzP) and mNP. To our knowledge, this is the first study on the biomonitoring of 17 phthalate metabolites in harbor porpoises.

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.

Urinary phthalate metabolites in primary school starters in Pearl River Delta, China: Occurrences, risks and possible sources

Assessment of children's exposure risks of phthalates before puberty is important, as phthalates are ubiquitous and are associated with reproductive development. However, relevant data in Pearl River Delta, China are scarce. Nineteen phthalate metabolites were analyzed in urine samples from 1490 primary school starters (6-8 years old) recruited in 2016-2017 using ultra-performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS). Nine phthalate metabolites were detected more than 80% of the urine samples. Monobutyl phthalate (MnBP) was the highest metabolite (median, 212 μg/g creatinine), followed by two short chained phthalate metabolites, four secondary metabolites of di(2-ethylhexyl) phthalate (DEHP), and the primary metabolites of DEHP. The MnBP level was the third highest of those reported worldwide while other metabolites were in the lower range compared with previous studies. Significantly positive associations were found between urinary metabolite levels and family income as well as parent education levels (p < 0.05). Duration since the latest interior decoration was inversely associated with phthalate metabolites (p < 0.05). Significantly positive associations had also been found between the frequency of eating takeaway food and four DEHP metabolites (p < 0.01). The geometric mean of estimated daily intake (EDI) of di-n-butyl phthalate (DnBP), DEHP, di-iso-butyl phthalate (DiBP), dimethyl phthalate, diethyl phthalate and butylbenzyl phthalate (BBzP) were 6.24, 2.67, 1.06, 0.64, 0.44, and 0.01 μg/kg bw/day, respectively. Hazard quotient (HQ) was defined as the ratio of EDI and the tolerable daily intake (TDI). Approximately 38% children had HQ _DnBP >1 indicating potential reproductive risks caused by DnBP. To evaluate cumulative exposure risks, hazard index (HI) was calculated as the sum of the HQs of DnBP, DiBP, DEHP, and BBzP. Nearly 48% children had HI > 1 suggesting extremely high cumulative risks in children in Pearl River Delta, China. To our best knowledge, this was the largest study on evaluating phthalate exposure among children in China.

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.

Prenatal exposure to phthalates and neurocognitive development in children at two years of age

BACKGROUND

Phthalates are a family of endocrine disruptors with short elimination half-lives in the human body. To date, few epidemiological studies have examined repeated measures of maternal urinary phthalates and the combined effects of prenatal exposure to multiple phthalates on children's neurocognitive development.

OBJECTIVES

We aimed to investigate the association between children's neurocognitive development at 2 years of age and prenatal phthalate exposure, as assessed by repeated measurements during pregnancy, and to further examine the effects of co-exposure to multiple phthalates using cumulative risk assessment.

METHOD

Within a prenatal cohort in Wuhan, China, we measured five high-molecular-weight (HMW) phthalates and three low-molecular-weight (LMW) phthalate metabolites' concentrations in three urine samples collected in the 1st, 2nd, and 3rd trimester of pregnancy from each mother. We assessed neurocognitive development by Bayley Scales of Infant and Toddler Development (BSID) at 2 years of age (n = 476) to obtain the children's mental development index (MDI) and psychomotor development index (PDI).

RESULTS

Higher exposure levels to LMW phthalates compared to HMW phthalates were observed in our population. Ln-transformed averaged concentration of mono-n-butyl phthalate (MnBP), a metabolite of the LMW phthalate di-n-butyl phthalate (DnBP) during pregnancy, was associated with decreased PDI scores in all children (β = -1.90, 95% CI: -3.43, -0.37). Similarly, the averaged sum concentration of ∑dibutyl phthalate (∑DBP) was associated with decreased PDI scores in all children (β = -1.89, 95% CI: -3.63, -0.15). A negative trend of association between exposure to HMW phthalates and PDI scores was observed in girls, while a positive association was found in boys. In cumulative risk assessment analyses, we consistently observed that the hazard quotient of DnBP (the parent compound of MnBP) was inversely associated with PDI scores in all children, whereas the hazard quotient of di-2-ethylhexyl phthalate (DEHP), an HMW phthalate, was positively associated with PDI scores in boys only.

CONCLUSIONS

This study is the first to use repeated measurement of maternal urinary phthalates in all three trimesters to assess prenatal exposure in relation to children's neurodevelopment. Our study suggested a negative association between prenatal exposure to MnBP and children's psychomotor development, and potentially sex-specific associations between HMW phthalates and neurocognitive development among boys and girls. These findings warrant further confirmation.

Association between urinary phthalate metabolites and obesity in adult Korean population: Korean National Environmental Health Survey (KoNEHS), 2012-2014

Background

Phthalate is a chemical that is commonly used as a plasticizer in processing plastic products and as a solvent in personal care products. Although previous experimental studies have reported that phthalate metabolites are associated with obesity, epidemiological study results have been inconsistent and insufficient. The objective of the present study was to investigate the association between urinary phthalate metabolites and obesity in adult Korean population.

Methods

The present study selected 4,752 Korean adults aged 19 years or older from the 2012–2014 Korean National Environmental Health Survey data. The concentrations of urinary di-(2-ethyl-5-carboxypentyl) phthalate (DEHP) metabolites—i.e., mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-(2-ethyl-5-carboxypentyl) phthalate—mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP) were adjusted using the urinary creatinine. We used logistic regression analysis to investigate the association between urinary phthalate metabolite concentration and body mass index (BMI) with respect to sex and age.

Results

Among women, urinary MEHHP and DEHP concentrations were found to have statistically significantly positive associations with obesity (Q4 versus Q1; odds ratio (OR): 1.72, 95% confidence interval (CI): 1.19–2.49 for MEHHP and OR: 1.52, 95% CI: 1.04–2.21 for DEHP). Among men, urinary MnBP concentration was found to have statistically significantly negative association with obesity (Q4 versus Q1; OR: 0.71, 95% CI: 0.50–0.99). In the analysis stratified by sex and age, women aged ≥ 50 years showed statistically significantly positive associations between the concentrations of urinary DEHP metabolites, DEHP, MBzP, and obesity (Q4 versus Q1; OR: 1.94, 95% CI: 1.28–2.94 for MEHHP, OR: 1.88, 95% CI: 1.21–2.94 for MEOHP, OR: 2.04, 95% CI: 1.31–3.18 for DEHP, and Q3 versus Q1; OR: 1.45, 95% CI: 1.02–2.05 for MBzP). Meanwhile, men aged ≥ 50 years showed no significant associations between urinary phthalate concentrations and obesity.

Conclusions

In the present study, we found differences in the associations between urinary phthalate metabolites and BMI according to sex and age. However, because the present study was cross-sectional in nature, additional support through prospective studies is needed to estimate the causal associations.

Phthalates and asthma in children and adults: US NHANES 2007-2012

Environmental exposure to phthalates may contribute to an increased risk of asthma in children and adults. We aimed to assess the direction and strength of the association between urinary phthalates metabolites and current asthma in children and adults that participated in the National Health and Nutrition Examination Survey (NHANES) 2007-2012. Data on ten urinary phthalate metabolites, self-reported questionnaires, spirometry measures, and covariates were obtained from 7765 participants (28.1% were children aged 6-17 years) taking part in the NHANES 2007-2012. Asthma was assessed using self-reported questionnaires for children and adults, and via spirometry measures for adults alone. We used crude and adjusted logistic regression models to estimate the odds ratios (ORs) and 95% confidence interval (CI) per one log₁₀ unit change in the concentration of phthalate metabolites. We further modeled the effect modification by sex. Out of 10 metabolites, only mono-benzyl phthalate (MBzP) was positively associated with the prevalence of self-reported asthma in children, after adjusting for a range of potential confounders (odds ratio 1.54; 95% confidence interval 1.05-2.27). No significant relationship was observed for adults. The association of mono-ethyl phthalate (MEP) was modified by sex, with significantly increased odds of asthma among males [boys (2.00; 1.14-3.51); adult males (1.32; 1.04-1.69)]. While no other phthalates showed a positive relationship with current asthma in males, mono-(carboxynonyl) phthalate (MCNP) and mono-(3-carboxylpropyl) phthalate (MCPP) were inversely associated with spirometrically defined asthma in adult females. A sex-specific relationship in adults was evident when spirometry, but not self-reported measures were used to define asthma. We found no clear association between exposure to phthalates and current asthma, except for a significant relationship between MBzP metabolites and self-reported asthma in children. As a result, exposure to phthalates and asthma development and/or exacerbations remains controversial, suggesting a need for a well-designed longitudinal study.

Mothers and children are related, even in exposure to chemicals present in common consumer products

BACKGROUND

Phthalates, bisphenol A (BPA) and triclosan (TCS) are detectable in the vast majority of people. Most humans are continuously exposed to these chemicals due to their presence in food or in everyday consumer products. The measurement of these compounds in family members may help to explore the impact of major lifestyle factors on exposure. Mothers and (young) children are especially interesting to study, as they mostly share considerable parts of daily life together.

MATERIALS AND METHODS

Phthalate metabolites, bisphenol A (BPA) and triclosan (TCS) were measured in first morning void urine, collected in mother-child pairs (n = 129) on the same day. The mothers (27-45y) and their children (6-11y) were recruited in the Brussels agglomeration and rural areas of Belgium in the context of the European COPHES-DEMOCOPHES human biomonitoring project. Face-to-face questionnaires gathered information on major exposure sources and lifestyle factors. Exposure determinants were assessed by multiple linear regression analysis.

RESULTS

The investigated compounds were detectable in nearly all mothers (92.8-100%) and all children (95.2-100%). The range (P₉₀ vs. P₁₀) of differences in urinary concentrations within each age group was for most compounds around 10-20 fold, and was very high for TCS up to 35 and 350-fold in children and mothers respectively. Some participants exceeded the tolerable daily intake guidelines as far as they were available from the European Food Safety Authority (EFSA). Overall, for BPA, the urinary concentrations were similar among both age groups. Most urinary phthalate metabolites were higher in children compared to the mothers, except for monoethyl phthalate (MEP). TCS levels were generally higher in the mothers. Despite the difference in mothers' and children's urinary concentrations, the creatinine-corrected levels were correlated for all biomarkers (Spearman rank r = 0.32 to 0.66, p < 0.001). Furthermore, for phthalates, similar home and lifestyle factors were associated with the urinary concentrations in both age groups: home renovation during last two years or redecoration during the last year for di-ethyl phthalate (DEP); PVC in home for di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP) and butyl benzyl phthalate (BBzP), and personal care products use for DiBP and DnBP. Based on questionnaire information on general food type consumption patterns, the exposure variability could not be explained. However, comparing the phthalate intake from the current study with earlier assessed Belgian food intake calculations for both ages, food in general was estimated to be the major intake source for di-ethyl hexyl phthalate (DEHP), with diminishing importance for BBzP, DiBP and DnBP.

CONCLUSION

Our results confirm, that children and their mothers, sharing diets and home environments, also share exposure in common consumer products related chemicals. By collecting morning urine levels on the same day, and using basic questionnaires, suspected exposure routes could be unraveled.

Determinants of phthalate exposure and risk assessment in children from Poland

Phthalates are a group of widely used chemicals and humans are exposed to them in their daily life. Some phthalates may affect the hormonal balance in both children and adults. The aim of this study was to assess the phthalate exposure and its determinants among children at age of 7 years from the Polish Mother and Child Cohort Study (REPRO_PL). 250 urine samples collected in 2014-2015 were analysed for 21 metabolites of 11 parent phthalates using on-line high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). This represents the most extensive set of phthalate metabolites ever determined for Poland. Ten metabolites were quantifiable in 100% of the samples, another eight in >90%. The highest median concentrations were found for the primary monoester metabolites of di-iso-butyl (MiBP, 72.4 μg/l), di-n-butyl (MnBP, 56.3 μg/l) and diethyl (MEP, 42.0 μg/l) phthalate, followed by the sum of di-2-ethylhexyl (ΣDEHP, 89.3 μg/l) and di-iso-nonyl (ΣDiNP, 21.9 μg/l) phthalate metabolites. Metabolite concentrations were higher in children at 7 years than in the same children at age 2 or in their mothers during pregnancy. Generally, phthalate exposures in this study were much higher than exposures reported in other European populations. Multivariate regression models showed that body mass index, place of residence, breastfeeding duration, socio-economic status and parental education were associated with the metabolite levels in the 7-year old children. Daily intake and hazard index calculations revealed that a small percentage of children (around 3-10%) exceeded the tolerable daily intakes established by international institutions such as EFSA and U.S. EPA indicating that these children might be at risk of anti-androgenic effects from the individual and cumulative exposure to phthalates. Thus, further monitoring of this population, by educational programs and follow-up interventions, is required.

Mediation analysis for the relationship between urinary phthalate metabolites and type 2 diabetes via oxidative stress in a population in Jeddah, Saudi Arabia

Human exposure to phthalates is ubiquitous and has received considerable attention due to their association with adverse health outcomes, including type 2 diabetes mellitus (T2DM). Nevertheless, earlier studies that link phthalate exposure to T2DM yielded ambiguous results. Furthermore, studies that associate phthalate exposure with oxidative stress and then with T2DM are scant. In this diabetic case-control study, urine samples collected from 101 individuals aged 28-68 years from Jeddah, Saudi Arabia, were analyzed to determine 20 phthalate metabolites (PhMs) and seven oxidative stress biomarkers (OSBs). Unconditional logistic regression was used to estimate odds ratios for the association between diabetes and urinary PhMs and OSBs in participants, stratified by age, gender, nationality, smoking status, occupation, and urinary creatinine. Twelve PhMs and five OSBs were found at detection rates above 50%, with geometric mean concentrations of 0.61-100 and 0.35-10.7 ng/mL (1.04-171 and 0.61-18.6 μg/g creatinine), respectively. Almost all exposures were significantly higher in diabetic cases than in controls. The 12 PhMs were positively associated with higher urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F_2α (8-PGF_2α). Individuals in the 3rd and/or 4th quartile(s) for urinary concentrations of PhMs and OSBs showed 3.7- and 7.3-fold increase, respectively, in the odds of having diabetes compared with those in the 1st quartile. The rank order of association of PhMs/OSBs with diabetes followed the order of: mEP ≈ mBP > mEHP > mCPP > mECPP ≈ mEOHP ≈ mEHHP ≈ mIBP ≈ mMP > mCMHP ≈ mBzP and 8-OHdG > 8-PGF_2α ≈ 15-PGF_2α. The relationship between phthalate exposure and risk of developing T2DM was mediated in part by phthalate-induced oxidative stress, especially 8-OHdG. Our study suggests that human exposure to phthalates is associated with increased oxidative stress which mediates the development of T2DM.