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

Pollution characteristics, sources, and health risks of phthalate esters in ambient air: A daily continuous monitoring study in the central Chinese city of Nanchang

In recent years, the atmospheric pollution caused by phthalate esters (PAEs) has been increasing due to the widespread use of PAE-containing materials. Existing research on atmospheric PAEs lacks long-term continuous observation and samples from cities in central China. To investigate the pollution characteristics, sources, and health risks of PAEs in the ambient air of a typical city in central China, daily PM2.5 samples were collected in Nanchang from November 2020 to October 2021. In this study, the detection and quantification of six significant PAE contaminants, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), Di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisodecyl phthalate (DIDP), were accomplished using gas chromatography and mass spectrometry. The results revealed that the concentrations of DEP, DnBP, DEHP, and DnOP were relatively high. Higher temperatures promote the volatilization of PAEs, leading to an increase in the gaseous and particulate PAE concentrations in warm seasons and winter pollution scenarios. The results of principal component analysis show that PAEs mainly come from volatile products and polyvinylchloride plastics. Using positive matrix factorization analysis, it is shown that these two sources contribute 67.0% and 33.0% in atmosphere PAEs, respectively. Seasonally, the contribution of volatile products to both gaseous and particulate PAEs substantially increases during warm seasons. The residents in Nanchang exposed to PAEs have a negligible non-cancer risk and a potential low cancer risk. During the warm seasons, more PAEs are emitted into the air, which will increase the toxicity of PAEs and their impact on human health.

The role of estrogen receptors (ERs)-Notch pathway in thyroid toxicity induced by Di-2-ethylhexyl phthalate (DEHP) exposure: Population data and in vitro studies

BACKGROUND

This study aimed to assess the exposure level and risk of Di-2-ethylhexyl Phthalate (DEHP) among adults in Jilin Province, China, clarify the impact of DEHP on human thyroid function, and to explore the role of estrogen receptors (ERs)-Notch signaling pathway in the effect of DEHP metabolites on thyroid hormones based on population data and in vitro experiments.

METHODS

312 adults participated in this study. Urinary DEHP metabolites were determined by high performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). Two pharmacokinetic models were used to evaluate the estimated daily intake (EDI) and hazard quotient (HQ) of the adults. Multiple linear regression and mediating effect models were used to evaluate the target associations. In cell experiments, thyroid follicular epithelial (Nthy-ori3-1) cells were exposed to mono (2-ethylhexyl) phthalate (MEHP) for testing. The inhibitions of ERα and Notch pathway were conducted by siRNA and Notch pathway inhibitor DAPT.

RESULTS

The detection rate of five DEHP metabolites was 97.1∼100.0%. The HQ value of 0.3% of adults was higher than 1. The levels of urinary DEHP metabolites were significantly correlated with thyrotropin (TSH), thyrotropin-releasing hormone (TRH), total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3) and free thyroxine (FT4) and gene (estrogen receptor α (ERα), Notch1, Dll4) levels. The ERα-Notch pathway played a mediating role in the association between DEHP metabolite levels and FT4. The cell results showed, the levels of FT3 and FT4 in cell supernatant decreased after MEHP exposure, and the downward trend was reversed after ERα and notch pathways were inhibited, notch pathway genes also decreased after ERα inhibition.

CONCLUSION

Adults in the Jilin Province of China were widely exposed to DEHP. ERs-Notch pathway played an important role in the effect of DEHP metabolites on thyroid hormones.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

DISCUSSION

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

CONCLUSIONS

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

Risk assessment and environmental determinants of urinary phthalate metabolites in pregnant women in Southwest China

Pregnant women are widely exposed to phthalic acid esters (PAEs) that are commonly used in most aspects of modern life. However, few studies have examined the cumulative exposure of pregnant women to a variety of PAEs derived from the living environmental conditions in China. Therefore, this study aimed to determine the urinary concentrations of nine PAE metabolites in pregnant women, examine the relationship between urinary concentrations and residential characteristics, and conduct a risk assessment analysis. We included 1,888 women who were in their third trimester of pregnancy, and we determined their urinary concentrations of nine PAE metabolites using high-performance gas chromatography-mass spectrometry. The risk assessment of exposure to PAEs was calculated based on the estimated daily intake. A linear regression model was used to analyze the relationship between creatinine-adjusted PAE metabolite concentrations and residential characteristics. The detection rate of five PAE metabolites in the study population was > 90%. Among the PAE metabolites adjusted by creatinine, the urinary metabolite concentration of monobutyl phthalate was found to be the highest. Residential factors, such as housing type, proximity to streets, recent decorations, lack of ventilation in the kitchen, less than equal to three rooms, and the use of coal/kerosene/wood/wheat straw fuels, were all significantly associated with high PAE metabolite concentrations. Due to PAE exposure, ~ 42% (n = 793) of the participants faced potential health risks, particularly attributed to dibutyl phthalate, diisobutyl phthalate, and di(2-ethyl)hexyl phthalate exposure. Living in buildings and using coal/kerosene/wood/wheat straw as domestic fuel can further increase the risks.

Selenium attenuates the association of co-exposure to arsenic, cadmium, and lead with cognitive function among Chinese community-dwelling older adults

The effects of interactions between the toxic and essential metal mixtures on cognitive function are poorly understood. This study aims to identify the joint association of arsenic (As), cadmium (Cd), and lead (Pb) with cognitive function in older adults and the moderating role of selenium (Se), zinc (Zn), and copper (Cu) in this association. This study included 1000 community-dwelling older adults. Cognitive function was assessed by the Mini-Mental State Examination (MMSE). Blood concentrations of As, Cd, Pb, Se, Zn, and Cu were measured using inductively coupled plasma mass spectrometry. Linear regression and Bayesian kernel machine regression (BKMR) models were applied to assess the individual and joint associations of As, Cd, and Pb with cognitive function and to examine whether Se, Zn, and Cu (individually and as a mixture) modified these associations. In the adjusted single-metal models, both Cd (β = - 0.37, 95% CI: - 0.73 to - 0.01) and Pb (β = - 0.44, 95% CI: - 0.86 to - 0.02) were associated with MMSE scores, while Se (β = 0.71, 95% CI: 0.30 to 1.13) exhibited a positive relationship with MMSE scores. Univariate exposure-response functions from BKMR models showed similar results. Moreover, the toxic metal mixture (As, Cd, and Pb) exhibited a significant negative association with MMSE scores in a dose-response pattern, with Pb being the greatest contributor within the mixture. The negative association of Pb alone or the toxic metal mixture with MMSE scores became weaker at higher concentrations of Se within its normal range, especially when Se levels were greater than the median (89.18 μg/L). Our findings support that Se can attenuate the negative associations of exposure to single Pb or the As, Cd, and Pb mixtures with cognitive function. Future prospective studies are needed to replicate our findings.

The association between essential trace element mixture and atherosclerotic cardiovascular disease risk among Chinese community-dwelling older adults

The evidence about the association of the essential trace element (ETE) mixture with atherosclerotic cardiovascular disease (ASCVD) amongst older adults is limited. This study aims to evaluate the associations of single ETEs and the ETE mixture with the 10-year ASCVD risks and its predicting factors in Chinese community-dwelling older adults. A total of 607 community-dwelling older adults were included in this study. Blood levels of vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), and selenium (Se) were assessed by inductively coupled plasma mass spectrometry. The predicted 10-year ASCVD risk was calculated using the Prediction for ASCVD Risk in China (China-PAR) equations. Traditional linear regressions and Bayesian kernel machine regression (BKMR) were used to assess the associations of single ETEs and the ETE mixture with the 10-year ASCVD risks and its predicting factors such as systolic blood pressure (SBP), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), diabetes, and waist circumference (WC). In linear regression models, blood Cr levels were negatively associated with the 10-year ASCVD risks after adjustment for covariates (β =  - 0.07, 95% CI =  - 0.11 ~  - 0.03); The 3th quartile (Q3) of Se levels was also associated with a lower 10-year ASCVD risks when compared with the lowest quartile (Q1) of Se levels (β_Q3 vs. _Q1: - 0.12, 95% CI =  - 0.22 ~  - 0.02). In BKMR models, the negative associations of Cr and Se with the 10-year ASCVD risks were observed. Higher blood levels of ETE mixture were associated with decreased 10-year ASCVD risks in a dose-response pattern, with Cr having the highest value of the posterior inclusion probability (PIP) within the mixture. Furthermore, a positive association between Cr and HDL-C and a negative association between Se and SBP were found in both linear regression and BKMR models. Cr and Se were negatively associated with the 10-year ASCVD risks, individually and as a mixture. ETE mixture showed a linear dose-response association with decreased 10-year ASCVD risks, with Cr being the most important component within the mixture. The negative association of the ETE mixture with the 10-year ASCVD risks may be attributed to Cr and Se, mainly mediated by HDL-C and SBP, respectively. Further cohort studies are needed to clarify this association.

Phthalate exposure and DNA oxidative damage in young people of takeaway food lovers

Numerous studies have demonstrated the ubiquitous of phthalates in materials of food and food packaging, and the effects of regular eating takeaway food for a long time on human health and phthalate exposure levels were not fully investigated. A total of 288 college students who love eating takeaway food were recruited to explore phthalate exposure and oxidative stress, by measuring metabolites of traditional or alternative phthalates and 8-hydroxydeoxyguanosine (8-OHdG, a biomarker of DNA oxidative damage) in their urine samples. Both traditional and alternative phthalates were highly detected. Based on weekly frequency of takeaway eating collecting from questionnaire, the students were divided into four groups including level 1 (L1, < 3 times), level 2 (L2, 3-7 times), level 3 (L3, 8-12 times) and level 4 (L4, > 12 times). The total concentrations of all phthalate metabolites were 42.5-893 ng/mL in all students, which were significantly different among four groups, with the lowest level in L1 (p < 0.05). Checking with the generalized linear model (L1 as the reference), the concentrations of most phthalate metabolites increased 12.0-144% in L2 and L3 compared with those in L1. For each group increase, the concentrations of total metabolites, and metabolites of high and low molecular weight phthalates will increase by 0.156%, 0.128%, and 0.142%, respectively. Besides, levels of 8-OHdG (0.639-33.7 ng/mL) were positively correlated with phthalate daily exposure doses. The each increase of a percentage unit of daily exposure of phthalates, the concentrations of 8-OHdG will increase by 0.258-0.405%. However, levels of 8-OHdG were not significantly different among the four groups. The alternative phthalates have already entered the body of Chinese young people. Our results indicated the regular consumption of takeaway food (e.g., more than three times per week) may increase the chance of exposure to certain phthalates, and may not significantly increase the levels of DNA oxidative damage, unless exposed to other pollutants such as phthalates.

National-scale urinary phthalate metabolites in the general urban residents involving 26 provincial capital cities in China and the influencing factors as well as non-carcinogenic risks

Phthalates (PAEs) are widely used in daily products but can cause a variety of adverse effects in humans. Few studies have been carried out on human internal exposure levels of PAEs on a large-scale, especially in developing countries. In the present study, 1161 urine samples collected from residents of 26 provincial capitals in China were analyzed for nine phthalate metabolites (mPAEs). The chemicals were widely detected, and the median specific gravity adjusted urinary concentration of Σ₉mPAEs was 278 μg/L. Di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) were the main parent PAEs that the residents were exposed to. Demographic characteristics, such as age and educational level, were significantly associated with PAE exposure. Children and the elderly had higher mPAE levels. Subjects with lower educational levels were more frequently exposed to DnBP and DEHP. However, mono-ethyl phthalate showed the opposite trend, i.e., higher concentrations in subjects aged 18-59 years and with higher educational levels. Geographic differences were detected at the national scale. Residents in northeastern and western China had higher levels of mPAEs than those in central China, most likely because of different industrial usage of the chemicals and different living habits and living conditions of the residents. Health risk assessment showed that hazard indices of PAEs ranged from 0.07 to 9.34, with 20.0% of the subjects being concern for potential non-carcinogenic risk as assessed by Monte Carlo simulation. DEHP and DnBP were the primary contributors, representing 96.7% of total risk. This first large-scale study on PAE human internal exposure in China provides useful information on residents' health in a developing country, which could be used for chemical management and health protection.

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

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

The associations of urinary DEHP metabolite levels, serum thyroid hormones, and thyroid-related genes among the adolescent students from China: a cross-sectional study

Our study aimed to investigate the associations between DEHP exposure and serum thyroid hormone levels in 347 adolescents and young adults. We measured DEHP metabolites including mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-carboxymethyl)hexyl phthalate (MCMHP) in their urine. Total thyroxine (TT4), total triiodothyronine, free triiodothyronine, free thyroxine (FT4), thyroid-stimulating hormone and the mRNA levels of thyroid peroxidase (TPO), thyroglobulin (TG), sodium iodide symporter (NIS), thyroid transcription factor 1 (TTF-1), and paired box gene 8 (PAX-8) in serum were measured. The results of statistical analysis showed that urinary DEHP metabolites were generally negatively associated with TT4 levels in serum. In the males, the FT4 levels showed positive associations with urinary MEHP, MECPP, MCMHP, and ∑DEHP. The mRNA level of TG was significantly positively correlated with the levels of MECPP, MCMHP, and ∑DEHP, while the levels of TTF-1 and PAX-8 mRNA were significantly positively correlated with the levels of DEHP metabolites. Taken together, DEHP may affect the synthesis of TG by altering the normal transcription of TTF-1 and PAX-8, leading to decreased TT4 levels in Chinese adolescents.

The Association of Bisphenol A and Phthalates with Risk of Breast Cancer: A Meta-Analysis

Background: Breast cancer is the most common cancer and the second leading cause of cancer-related death amongst American women. Endocrine-disrupting chemicals (EDCs), especially bisphenol A (BPA) and phthalates, have adverse effects on human health. However, the association of BPA and phthalates with breast cancer remains conflicting. This study aims to investigate the association of BPA and phthalates with breast cancer. Methods: Correlative studies were identified by systematically searching three electronic databases, namely, PubMed, Web of Sciences, and Embase, up to November 2020. All data were analyzed using Stata 15.0. Results: A total of nine studies, consisting of 7820 breast cancer cases and controls, were included. The urinary phthalate metabolite mono-benzyl phthalate (MBzP) and mono-2-isobutyl phthalate (MiBP) were negatively associated with breast cancer (OR = 0.73, 95% CI: 0.60–0.90; OR = 0.75, 95% CI: 0.58–0.98, respectively). However, the overall ORs for BPA, mono-ethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(3-carboxypropyl) phthalate (MCPP), and mono-butyl phthalate (MBP) were 0.85 (95% CI: 0.69–1.05), 0.96 (95% CI: 0.62–1.48), 1.12 (95% CI: 0.88–1.42), 1.13 (95% CI: 0.74–1.73), 1.01 (95% CI: 0.74–1.40), 0.74 (95% CI: 0.48–1.14), and 0.80 (95% CI: 0.55–1.15), respectively, suggesting no significant association. The sensitivity analysis indicated that the results were relatively stable. Conclusion: Phthalate metabolites MBzP and MiBP were passively associated with breast cancer, whereas no associations were found between BPA, MEP, MEHHP, MEHP, MEOHP, MCPP, and MBP and breast cancer. More high-quality case-control studies or persuasive cohort studies are urgently needed to draw the best conclusions.