Exposure to multiple trace elements and miscarriage during early pregnancy: A mixtures approach

Relationship between seminal plasma trace elements and sperm quality

Male fertility has declined recently, mainly due to reduced sperm quality. While common factors contribute to this issue, they do not adequately explain all cases. Environmental pollutants, especially trace elements, significantly affect sperm quality, but the link between trace element exposure in seminal plasma and male fertility decline is still poorly understood. Here, inductively coupled plasma mass spectrometry was employed to detect 25 trace elements in seminal plasma from 209 Chinese men of reproductive age. The study utilized logistic regression and restricted cubic splines to examine the relationship between specific trace elements and semen parameters across different groups. Group comparisons revealed that the concentrations of Mg, Ca, Fe, Cu, Zn, Mn, Sr, Cd, and Co were significantly higher in patients with asthenozoospermia. The concentration of Mo was significantly lower in patients with teratozoospermia. Notably, the trace element exposure levels in patients with oligozoospermia were comparable to those of healthy individuals. Additionally, correlation analyses indicated that Mg, Ca, Fe, Zn, As, and Cd levels positively correlated with sperm DFI. Furthermore, significant positive correlations were identified between the Mg, Fe, Zn, and Tl concentrations and sperm concentration. Low Cu, Mn, and Co levels positively correlated with sperm concentration. Mg, Zn, Cd, and low concentrations of Co were negatively correlated with sperm motility. This study presents the largest-scale profile of trace element exposure in seminal plasma to date, emphasizing the significance of seminal trace elements as biomarkers that accurately reflect the environmental exposure levels of male germ cells. Our findings suggest that increased trace elements, particularly metal elements, in seminal plasma primarily reduce sperm motility rather than affecting sperm concentration or morphology. Further studies are needed to explore the biological mechanisms that link seminal trace elements to male fertility decline.

Toxic metals and trace elements, markers of inflammation, and hyperandrogenemia in women and testosterone deficiency in men: Associations and potential mediating factors

There is evidence suggesting that toxic metal and trace element exposure disrupts androgen levels. However, specific effects of such exposure on hyperandrogenemia (HA) in women and testosterone deficiency (TD) in men remain unclear. The study investigated associations between toxic metal and trace element exposure and HA in women and TD in men, utilizing data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2016, and included 2205 women and 2621 men. Single-exposure analyses found lead (Pb) (adjusted odds ratio [aOR] 1.19, 95 % confidence interval [CI] 1.04-1.36) and cadmium (Cd) (aOR 1.20, 95 % CI 1.03-1.39) were positively associated with HA, especially strong in women over the age of 35. Manganese (Mn) was positively associated with TD (aOR 1.15, 95 % CI 1.03-1.28), especially strong in men aged between 45 and 50 years and obese men. A grouped weighted quantile sum (GWQS) model was performed to assess the effects of combined exposure, and found toxic metal mixture was positively associated with HA, particularly Cd (0.59) and Pb (0.40), and trace element mixture was positively associated with TD, particularly Mn (0.78). Mediation analyses demonstrated inflammation, particularly monocyte count and alkaline phosphatase (ALP) mediated 7.5-11.76 % of the associations. These findings provide insights to inform interventions for reducing exposure.

Associations of individual and mixtures of organophosphate pesticides with the risk of osteoporosis in adult population

The impact of organophosphate pesticide (OPP) exposure on osteoporosis in adult population remains unclear. Thus, it is necessary to explore the association between the exposure to a mixture of OPPs and the prevalence of osteoporosis as well as to identify the major contributor of OPPs in this association. Participants were selected from the 2005-2008 cycle of the NHANES cross-sectional study. OPP exposure was estimated using six different metabolites found in urine. Dual-energy X-ray absorptiometry (DXA) was used to measure bone mineral density (BMD). Survey-weighted generalized linear regression models (SWGLMs) were used to estimate the association between individual OPP exposure and osteoporosis/BMD. Weighted quantile sum (WQS) regression and quantile g-computation (Qgcomp) models were used to assess the mixture of OPPs and identify the key pollutants. SWGLMs indicated that higher concentrations of dimethyl dithiophosphate (DMDTP) and diethyl dithiophosphate (DEDTP) were associated with increased osteoporosis risk in the upper quartiles. WQS models revealed a significant combined effect of six OPP metabolites on osteoporosis (OR = 1.35, 95% CI: 1.06-1.73, P = 0.015), femoral neck BMD (β = -0.012, 95% CI: -0.020, -0.004, P = 0.003) and lumbar spine BMD (β = -0.015, 95% CI: -0.025, -0.006, P = 0.001), with DMDTP and DEDTP identified as key pollutants. Results from the Qgcomp models showed no substantial changes. This study indicated that exposure to both individual OPPs and their mixtures were associated with decreased BMD and increased osteoporosis risk, with DMDTP and DEDTP identified as major contributors to these associations. This underscores the need to prioritize control of these two pollutants to limit their exposure for osteoporosis prevention.

Exposome-wide association study of thyroid function using U.S. National Health and Nutrition Examination Survey data

Previous epidemiologic studies examining thyroid function and chemical exposures have typically focused on a single or a limited number of chemical classes, often neglecting the effects of chemical mixtures. This study addressed this gap by exploring the associations between exposure to hundreds of chemicals and thyroid function using an exposome-wide association study (ExWAS) approach and National Health and Nutrition Examination Survey (NHANES) data. We analyzed data from three NHANES cycles (2007-2008, 2009-2010, and 2011-2012), which include measures of thyroid function (free and total triiodothyronine [T3], free and total thyroxine [T4], thyroid-stimulating hormone [TSH]) and chemical biomarker concentrations from 9,082 participants. For adolescents (aged 12-19 years) and adults (aged ≥20 years), we employed multiple regression by accounting for survey weights to identify biomarkers associated with thyroid function test levels and used Bayesian group weighted quantile sum (BGWQS) regression to assess the effects of chemical mixtures on these measurements. After adjusting for multiple comparisons, we found in single exposure scenarios that 44 and 67 biomarkers were associated with at least one thyroid function measure in adolescents and adults, respectively (adjusted p-value <0.05). In scenarios involving mixed chemical exposures, groups such as pesticides, sodium/iodide symporter (NIS) inhibitors, and metals were associated with alterations in thyroid hormones or TSH across both age groups. Volatile organic compounds were specifically linked to lower T4 levels in adolescents, whereas phenols and parabens were associated with lower TSH levels exclusively in adults. Although limited by the cross-sectional data, this study identified chemical biomarkers linked to thyroid function.

Toxic Effects of Exposure to Phthalates on Cardiac Injury Biomarkers: Evidence from NHANES 1999-2004

Background: Humans are consistently and increasingly exposed to phthalate products, but the effect of the combined exposure to phthalates on myocardial injury remains largely unexplored. The present study aimed to explore the effect of the combined exposure to phthalates on myocardial injury. Methods: A total of 1237 male adults (aged ≥20) without coronary artery disease (CAD) from the National Health and Nutrition Examination Survey (NHANES) in 1999-2004 were included in the current study. Multiple linear regression, Bayesian kernel machine regression (BKMR), and a weighted quantile sum (WQS) model were employed to examine the associations of urinary phthalate metabolites with two cardiac injury biomarkers, including troponin T (TNT) and troponin I, using four highly sensitive assays (Abbott, Chicago, IL, USA; Siemens, Erlangen, Germany; and Ortho, Raritan, NJ, USA) (TNIA, TNIS, TNIO). Results: According to the linear regression analysis, mono-(3-carboxypropyl) phthalate (MCPP, a metabolite of di-n-octyl phthalate) was found to be positively associated with serum TNT; a positive association was found between mono-isobutyl phthalate (MiBP, a metabolite of di-isobutyl phthalate) and TNIA, as well as MiBP and TNIS. Mono-benzyl phthalate (MBzP, a metabolite of butyl benzyl phthalate) and MCPP were positively associated with serum TNIO. The BKMR analyses showed a positive overall relationship of serum TNT, TNIA, TNIS, and TNIO with increased concentrations of phthalate metabolites. The WQS model showed MCPP and MBzP were the top two contributors to being an increased risk for elevated TNT levels. MCPP and mono-ethyl phthalate (MEP, a metabolite of diethyl phthalate) were identified as the leading contributors to increased TNIA and TNIS. MCPP and MBzP were the dominant contributors to elevated TNIO. Conclusions: As a combined mixture, phthalate metabolites were positively associated with serum TNT and TNI among adults without CAD, indicating the potential toxic effect of phthalate exposure on cardiac injury.

Associations between phenol and paraben exposure and the risk of developing breast cancer in adult women: a cross-sectional study

Increasing evidence suggests that endocrine-disrupting chemicals (EDCs) have adverse effects on breast cancer (BC). The aim of this study was to assess the association between exposure to prevalent EDCs-phenols and parabens-and the risk of developing BC. Data on urinary bisphenol A (BPA), triclosan (TRS), benzophenone-3 (BP3), methyl paraben (MPB), ethyl paraben (EPB), propyl paraben (PPB), and butyl paraben (BUP) were obtained from the 2005-2014 National Health and Nutrition Examination Survey. A total of 4455 subjects were included in this cross-sectional study. The results from the weighted multivariable regression models indicated that exposure to elevated concentrations of TRS increased the risk of developing BC by 2.33 (Q2: 95% CI = 1.45-3.75, p < 0.001) and 1.94 times (Q3: 95% CI = 1.21-3.09, p = 0.006), respectively. The nonlinear association between TRS concentrations and the risk of developing BC was statistically significant (P nonlinear = 0.007), with the restricted cubic splines (RCS) curve exhibiting an inverted U shape. The association between TRS concentrations and the risk of developing BC was more pronounced among overweight individuals (BMI ≥ 25 kg/m2), those aged < 60 years, and white individuals. Weighted quantile sum (WQS) and Bayesian Kernel Machine Regression (BKMR) analysis revealed no significant overall association between mixtures of urinary phenol and paraben metabolites and BC risk. However, TRS exposure was the most influential, with higher TRS concentrations (both continuous and categorical) significantly associated with an increased BC risk, particularly in overweight individuals (BMI ≥ 25 kg/m2), those aged < 60 years, and white individuals.

Association between alkali and alkaline earth elements in chorionic villus and risk for spontaneous abortion

Exposure to specific alkali and alkaline earth elements(AEs/AEEs) has been reported that are linked to an increased risk of spontaneous abortion. However, the direct evidence of exposure in the uterus are absent. Therefore, we collected chorionic villi after spontaneous abortion or induced abortion in Peking University Third Hospital. The concentrations of six alkali and alkaline earth elements in chorionic villi were measured using inductively coupled plasma mass spectrometry (ICP-MS). Through using logistic regression, Bayesian kernel machine regression (BKMR) and Weighted quantile sum regression (WQS) model, we assessed single and mixed exposure effects of alkali and alkaline earth elements on spontaneous abortion. In terms of the individual effect, high concentration group of barium (Ba) increased the risk of spontaneous abortion by 150 % (95 % CI: 1.38-4.51), whereas rubidium (Rb), cesium (Cs) and Magnesium (Mg) all clearly demonstrated dose dependency in reducing the incidence of spontaneous abortion. The BKMR model demonstrated that as the mixed exposure percentile increased, the likelihood of spontaneous abortion decreased almost linearly. For every quartile increasing in the WQS index, the risk of spontaneous abortion decreased (OR: 0.21, 95 % CI: 0.13-0.33), with Mg and Rb having the highest weights at 0.587 and 0.367, respectively. According to our findings, there were negative dose-response relationships between Mg and Rb levels and risk for spontaneous abortion, but exposure to higher concentration of Ba in the chorionic villi was positively associated with the risk of it.

Coexposure to ambient air pollution and temperature and its associations with birth outcomes in women undergoing assisted reproductive technology in Fujian, China: A retrospective cohort study

BACKGROUND

The interactions between pollutants and temperature coexposure, the mixing effects and their potential mechanisms remain uncertain.

METHODS

This retrospective cohort study included 11,766 women with infertility who received treatment at Fujian Hospital between 2015 and 2024. The daily mean concentrations of the six pollutants and the relative humidity and temperature data were acquired from the Fujian region. Data on genes were obtained from the Comparative Toxicogenomics Database.

RESULTS

O3 (aOR=0.80, 95 % CI=0.725--0.891) and temperature (aOR=0.936, 95 % CI=0.916--0.957) were negatively correlated with live birth rates. Moreover, PM10 (aOR=1.135, 95 % CI=1.028--1.252) and PM2.5 (aOR=1.146, 95 % CI=1.03--1.274) were positively associated with preterm birth. Among the effects on live births, PM2.5, PM10, NO2, CO, and SO2 had significant synergistic effects with temperature; in addition, O3 had significant antagonistic effects with temperature. A notable trend toward declining live birth rates with elevated concentrations of mixed pollutants was observed. Different infertility patients have different sensitivities to coexposure. Gene enrichment and cell experiments are associated mainly with cellular life activities.

CONCLUSIONS

Individual effects, interactions, and mixed effects between temperature and air pollutants and birth outcomes persist when air pollutant levels are relatively low. AAP may trigger miscarriage through cytotoxic effects.

The relationships of metals exposure and disturbance of the vaginal microbiota with the risk of PROM: Results from a birth cohort study

The vaginal microbiota is proposed to be associated with reproductive health. Exposure to metals during pregnancy is a risk factor for premature rupture of membranes (PROM). PROM can lead to serious maternal complications, thus, identifying the cause and therapeutic targets for it is crucial. However, the role of vaginal microbiota in the association between metals exposure and the risk of PROM are not clear. Based on a prospective birth cohort study including 668 pregnant women, maternal blood levels of 15 metals in the first trimester (n=668) and microbiota of vaginal secretions in the third trimester (n=244) were assessed. The metals that significantly associated with the risk of PROM were screened out via four statistical models, the top three were barium (Ba), chromium (Cr) and thallium (Tl) according to their weight indices. The results from the BKMR model showed a positive association of the mixture (Ba, Cr and Tl) with the risk of PROM. PROM and non-PROM were characterised by different beta diversities, moreover, the relative abundances of Bifidobacterium, Corynebacterium and Collinsella were statistically and negatively related to the risk of PROM [the adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were 0.06 (0.00, 0.82), 0.32 (0.14, 0.74) and 0.50 (0.30, 0.84), respectively]. On the other hand, women with different levels of Ba exposure were also characterised by different beta diversities (p value = 0.047); and blood Ba levels were also negatively associated with the relative abundances of Collinsella; additionally, Cr levels were positively associated with alpha diversity indices [Shannon index: β (95 % CI) = 0.25 (0.01, 0.50); Simpson index: β (95 % CI) = 0.08 (0.00, 0.17), respectively]. The results from mediation analysis showed the proportion of the relationship between Ba exposure and PROM risk mediated by the relative abundance of Collinsella was 26.4 %. Further verification analysis exploring the potential cause of the above phenomenon indicated that the neutrophil count, one of blood inflammation indicators for PROM, was higher in women with the absence of Collinsella (p value = 0.039), moreover, the cumulative hazard of PROM for women with the presence of Collinsella was also significantly lower than that of those without Collinsella (p value = 0.007). Collectively, the changes in the diversity and composition of the bacterial community, especially the reduction in Collinsella abundance caused by metal exposure, may be related to the occurrence of PROM, which provides a new microbiota-based perspective for intervention in metal exposure-related PROM. Confirming these relationships and determining the possible processes at play will require more investigation.

Manganese exposure and perinatal health: a systematic review of literature

Manganese is essential for adequate feto-maternal health; however, an inverted U-shaped relation has been found between maternal manganese status and pregnancy complications. This systematic review summarizes the effect of maternal manganese exposure and perinatal health. We adopted a systematic approach to retrieve the recent literature. After applying the inclusion/exclusion criterion, a total of 20 studies were included in this review. Results found a non-significant relationship between maternal manganese exposure and risk of gestational diabetes mellitus (GDM), while only three studies reported the association between higher manganese levels and risk of preterm birth. Also, inconsistent results were found regarding higher manganese status and risk of low birth weight. This review reported no association between higher maternal manganese status andrisk of GDM. Nevertheless, the paucity of literature related to small for gestational age and pre-eclampsia prohibits a conclusion. Further studies are required for evaluation of environmental manganese exposure and maternal manganese status.

The associations between exposure to ambient air pollution and coagulation markers and the potential effects of DNA methylation

Previous studies have illustrated the pivotal role of coagulation biomarkers in the link between air pollution and cardiovascular disease (CVD). However, inconsistencies remain in the conclusions, with limited studies conducted in rural areas of China. We conducted a panel study in rural areas of Henan Province, China. Considering the potential effect modifications of atherosclerotic cardiovascular disease (ASCVD) risks, 104 participants were enrolled, comprising two matched groups: 52 with high ASCVD risks and 52 with low ASCVD risks. DNA methylation at CpG sites and coagulation indices were measured for all participants. Linear mixed-effect regression models were used to evaluate the associations between ambient air pollution, coagulation biomarkers, and DNA methylation. We observed that for every 5-day standard deviation (SD) increment of PM2.5 (11.91 μg/m³) and PM10 (13.65 μg/m³), fibrinogen increased by 7.70 % (95 %CI: 2.27, 13.12) and 8.50 % (95 %CI: 2.46, 14.55), respectively. SO2 (6.95 μg/m³) was associated with 40.25 % (95 %CI: 14.83, 65.67) increase in plasminogen activator inhibitor-1 (PAI-1). Decreased methylation at CpG sites was associated with exposure to air pollution. However, DNA methylation did not mediate the association between ambient air pollution and coagulation. Our study revealed the harmful impact of ambient air pollution on coagulation function but found no significant mediation effects of DNA methylation.

Trace elements exposure affects the outcomes of in vitro fertilization embryo transfer, a cohort study in Northern China

PURPOSE

With urbanization and industrialization process accelerated, humans are exposed more and more trace elements. This study aimed to explore the potential associations of trace elements with the outcomes of in vitro fertilization embryo transfer (IVF-ET).

METHODS

Total 181 women who underwent IVF-ET were enrolled, among which 89 women underwent fresh ET after IVF. Trace elements were measured in the serum and follicular fluid (FF) samples by inductively coupled plasma-mass spectroscopy. The associations of the levels of different trace elements with IVF-ET outcomes, including normal fertilization, high-quality embryos, and clinical pregnancy (fresh ET) were analyzed.

RESULTS

Twenty-five out of twenty-eight trace elements showed higher concentrations in the serum than those in the FF. Normal fertilization was positively associated with Cu and Mn in the FF. High-quality embryos was positively associated with Cu in the serum and FF, and Zn in the serum. Clinical pregnancy was positively associated with Ge in the serum, and inversely associated with Al, Ba, and Pb in the serum. Additionally, poor outcomes of IVF-ET should be noticed in women with FF level of Cu < 955.38 ng/mL, FF level of Mn < 3.42 ng/mL, serum level of Ge < 6.11 ng/mL, serum level of Al > 28.44 ng/mL, and serum level of Pb > 0.90 ng/mL.

CONCLUSIONS

IVF-ET outcomes were positively associated with Cu, Mn, Zn, and Ge, and inversely associated with Al and Pb. Properly controlling the exposure of relevant trace elements is necessary for patients with the need of IVF-ET.

The Impact of Minerals on Female Fertility: A Systematic Review

Female fertility and reproductive system disorders are influenced by a complex interplay of biological, physiological, and environmental factors. Minerals have emerged as crucial yet often overlooked elements that impact fertility and the prevalence of reproductive system disorders.

BACKGROUND/OBJECTIVES

This review aims to provide a comprehensive overview of the multifaceted role of minerals in female fertility, focusing on key areas such as oocyte quality, ovulation, embryo development, oxidative stress, miscarriage, hormonal regulation, environmental exposure, and in-vitro fertilization (IVF) outcomes.

METHODS

A systematic review was conducted, focusing on randomized controlled trials (RCTs), prospective cohort studies, case-control studies, nested case-control, and observational studies examining mineral supplementation and nutrition in women planning pregnancy or utilizing assisted reproduction technologies (ARTs). Relevant literature was sourced from multiple electronic databases, including PubMed, Scopus, Google Scholar, Web of Science, and the Cochrane Library, using keywords related to minerals and female fertility. The quality of studies was assessed using the Newcastle-Ottawa Scale (NCO) for non-randomized studies and the Risk of Bias (RoB) tool for RCTs. This systematic review has been registered on PROSPERO (registration number is CDR 42024547656).

RESULTS

From an initial pool of 20,830 records, 39 articles met the inclusion criteria and were analyzed. The studies addressed various reproductive outcomes influenced by minerals: embryo development, oocyte quality, oxidative stress, miscarriage, hormonal regulation, IVF outcomes, environmental exposure, and minerals as biomarkers. The analysis revealed that minerals like selenium, zinc, and copper are essential for maintaining reproductive health, while exposure to toxic metals such as cadmium and lead is detrimental.

CONCLUSIONS

This review highlights the crucial role of both mineral supplementation and serum mineral status in female fertility. The findings provide key insights for clinicians to improve reproductive health through targeted mineral intake and monitoring. Further research is needed to refine guidelines for supplementation and serum levels in women with fertility issues.

Serum arsenic augments gallstone risk in Henan rural cohort with multiple metal exposure

BACKGROUND

People are exposed to metals in various ways during their daily lives. However, the association between metal exposure and gallstones remains unclear.

OBJECTIVES

To investigate the relationship between serum elemental concentrations and the risk of gallstones.

METHODS

Participants (n = 4204) were drawn from the Henan Rural Cohort. Gallstone diagnosis was based on abdominal ultrasound reports during follow-up. Baseline serum elemental concentrations were measured using inductively coupled plasma mass spectrometry. The relationship between serum elemental levels and gallstones was evaluated using robust Poisson regression, restricted cubic spline (RCS), quantile g-computation (Qgcomp), grouped weighted quantile sum (GWQS) and Bayesian kernel machine regression (BKMR).

RESULTS

121 individuals were diagnosed with gallstone (incidence rate of 2.88 %). In robust Poisson regression, after adjusting for confounding factors, the highest quartile of arsenic concentration compared to the lowest quartile had a 1.90 times higher relative risk (RR) [95 % confidence interval (CI): 1.05, 3.44]. Conversely, the highest quartile of zinc concentration compared to the lowest quartile had a 0.50 times lower RR (95 % CI: 0.28, 0.89). RCS showed an approximately "S"-shaped nonlinear relationship between serum arsenic levels and gallstones, with increasing arsenic concentration leading to a higher risk of gallstones; however, the risk plateaued when arsenic concentration exceeded 0.62 μg/L. Both the Qgcomp and GWQS indicated that arsenic plays a significant role in increasing the risk of gallstones, whereas zinc plays a significant role in reducing the risk of gallstones. BKMR showed that raising arsenic exposure from the 25th to the 75th percentile increased the risk of gallstones, while raising serum zinc concentration reduced it.

CONCLUSIONS

Higher serum arsenic concentration increases the risk of gallstones, whereas higher zinc concentration may reduce the risk. Effective prevention of gallstones may require further reduction of arsenic exposure and appropriate increases in zinc intake.

The impact of metals on cognitive impairment in the elderly and the mediating role of oxidative stress: A cross-sectional study in Shanghai, China

Cognitive impairment (CI) is a prodrome of many neurodegenerative diseases with complex and unclear pathogenesis. Metal exposure has been found to be associated with CI, but existing population studies are scarce and have the limitations of single outcome and ignoring mixed exposures. This cross-sectional study was conducted in Shanghai, China, enrolling 836 seniors aged over 60 years to investigate the relationship between combined metal exposure (Lead (Pb), cadmium (Cd), and mercury (Hg)) and CI in the elderly and the mediating effect of oxidative stress. It was found that there were significant differences in urinary Pb, Cd, Hg and blood Pb levels between the CI and normal groups. Urinary Pb and Cd levels were significantly negatively correlated with Montreal Cognitive Assessment (MoCA) score, amyloid β42 (Aβ42), and Aβ42/40, while urinary Cd, Hg and blood Hg were significantly positively correlated with phosphorylated tau protein (P-tau). Weighted quantile sum (WQS) regression indicated that combined metal exposure had a more significant effect on CI than individual exposure. Mediation modeling revealed that plasma superoxide dismutase (SOD) was involved in the effects of urinary Cd on Aβ42/40 and P-tau, with mediation effects accounting for 20 % of the total effect. This study emphasized the combined exposure to metals, and the results can help to properly understand the association between mixed metals exposure and CI in the elderly, as well as provide population data and theoretical basis for identifying early environmental risk factors and discovering potential mechanisms of CI.

Using Four Machine Learning Methods to Analyze the Association Between Polycyclic Aromatic Hydrocarbons and Visual Impairment in American Adults: Evidence from NHANES

The causes of visual impairment are complex and may be influenced by exposure to environmental pollutants. Using data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES), we examined the association between exposure to ten polycyclic aromatic hydrocarbons (PAHs) and vision problems in 1149 U.S. adults. We employed various supervised learning methods, including variable selection techniques such as Lasso and elastic net, weighted quantile sum regression (WQS), and Bayesian kernel machine regression (BKMR), to assess the association between PAHs and the occurrence of visual impairments. The mediation effects between urinary 2-fluorene and inflammation were evaluated using mediation analysis. Both the lasso and elastic net models consistently identified two specific PAH congeners, 2-fluorene and 1-phenanthrene, as significant predictors. The WQS regression revealed a positive relationship between the PAH mixture and visual impairment, with notable contributions from urinary 2-fluorene (weight = 0.39) and 9-fluorene (weight = 0.21). BKMR analysis indicated that the likelihood of visual impairment increases with higher PAH exposure, showing a general upward trend. This trend also revealed a positive association between visual impairment and exposure to four specific PAH metabolites, including 2-fluorene. A significant mediation effect was observed for alkaline phosphatase (p = 0.03), with a proportion mediated of 10.48%. Our findings suggest a significant association between PAHs and visual impairment, with multiple statistical models consistently emphasizing the crucial role of 2-fluorene exposure. This study highlights the importance of considering environmental pollutants as significant contributors to visual health outcomes, providing insights for preventing visual impairment.

Associations of Co-Exposure to Polycyclic Aromatic Hydrocarbons and Heavy Metals with Sex Steroid Hormones among Children Aged 6-19 Years

INTRODUCTION

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are endocrine-disrupting chemicals (EDCs) that may have a combined effect on sex hormone levels in children. This study investigated the correlations between co-exposure to PAHs and HMs and levels of sex steroid hormones in children.

METHODS

We employed the data from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016, including 1,167 participants aged 6-19 years. Sex hormone indicators include testosterone (TT), estradiol (E2), sex hormone-binding globulin (SHBG), free androgen index (FAI), and the TT/E2 ratio. Weighted multivariate linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to analyze the associations between co-exposure to PAHs and HMs and sex steroid hormone levels.

RESULTS

Co-exposure to PAHs and HMs was associated with a 16.2% reduction (95% CI [-0.321, -0.004]) in SHBG level among prepubertal males and a 16% reduction (95% CI [-0.30, -0.03]) in E2 level among pubertal males by the WQS regression, and cadmium (Cd) and mercury (Hg) contributed the highest weight, respectively. In the Bayesian kernel machine regression (BKMR) model, co-exposure to PAHs and HMs was positively associated with TT/E2 in pubertal males and negatively correlated with FAI in pubertal females, and 1-hydroxypyrene (1-PYR) and Cd were the most important components, respectively.

CONCLUSIONS

Co-exposure to PAHs and HMs was associated with sex hormone levels in children. These findings highlight the necessity for preventing the effects of these chemicals on sex hormones.

Couples' preconception urinary essential trace elements concentration and spontaneous abortion risk: A nested case-control study in a community population

BACKGROUND

Previous studies have indicated a correlation between maternal imbalances in essential trace elements during pregnancy and the occurrence of spontaneous abortion (SA). Nonetheless, the impact of these elements from both partners and during the preconception period remains unexplored.

OBJECTIVE

This study sought to evaluate the relationship between preconception essential trace elements and spontaneous abortion (SA) based on husband-wife dyads.

METHODS

This study selected 390 couples with spontaneous abortion (SA) and 390 matched couples with live births from a preconception cohort of 33,687 couples. Urine samples collected prior to pregnancy were analyzed for ten essential trace elements (Se, Cr, Mo, Cu, Zn, Fe, Mn, V, Co, and Ni) using inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Multivariate conditional logistic regression analysis identified that elevated concentrations of Zn (OR = 0.73) and Ni (OR = 0.69) in couples were associated with a reduced risk of SA, whereas elevated levels of Cr (OR = 1.30) and Mn (OR = 1.39) were linked to an increased risk. Restricted cubic spline models suggested a U-shaped association between couples' Cu and Co concentrations and SA. Bayesian Kernel Machine Regression further supported a U-shaped relationship between the mixture of ten elements and SA, showing significant protection at the 50th and 55th percentiles compared to the 10th percentile. Additionally, the effects of Cr, Zn, Mn, and Ni on SA varied when the concentrations of the other nine elements were held constant at their 25th, 50th, and 75th percentiles. Stratified analysis revealed that maternal Cu (OR = 0.43) and Fe (OR = 0.63) reduced the risk of SA when paternal Cu and Fe were in the lower quartile. Conversely, maternal Cu (OR = 2.03) and Fe (OR = 1.77) increased the risk of SA when paternal concentrations were in the higher quartile. Similar patterns were observed for Cr, Mn, Co, and Zn.

CONCLUSION

Elevated urinary concentrations of Zn and Ni in couples were associated with a reduced risk of SA, while higher levels of Cr and Mn were linked to an increased risk. Cu, Co, and a mixture of ten essential trace elements exhibited a U-shaped relationship with SA. The impact of certain essential trace elements (Cu, Fe, Cr, Mn, Co, and Zn) on SA in one partner was influenced by their concentrations in the other partner.

Environmental exposure to metal(loid)s and hypertensive disorders of pregnancy: A systematic review

BACKGROUND

Environmental exposure to metal(loid)s has been associated with adverse effects on human health, but the systemic repercussion of these elements on the development of hypertensive disorders of pregnancy (HDP) is still poorly understood.

OBJECTIVE

To summarize evidence published about the influence of environmental exposure to aluminum, arsenic, barium, cadmium, lead, strontium and mercury on the development of HDP.

METHODS

We conducted a systematic literature review according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The search strategy was validated by the Peer Review of Electronic Search Strategies. We searched for articles published up to February 2023 in seven databases without language restriction. Two researchers conducted the steps for selection, data extraction and evaluation of the methodological quality of the instruments for epidemiological studies of the Joanna Briggs Institute. Any disagreements were resolved by a third researcher.

RESULTS

We obtained 5076 records, of which 37 articles met the inclusion criteria moderate to high methodological quality. Single exposure to metal(loid)s was predominant, and the leading biological matrix analyzed to detect the concentrations from exposure was maternal blood. Lead was the metal investigated the most, and had the largest number of studies showing positive association with HDP. In relation to the other metal(loid)s, higher levels were found in women with HDP in comparison with healthy women, but the finding of a cause-effect relationship was inconsistent.

CONCLUSIONS

Although we found evidence of harmful effects of the metal(loid)s studied on human health, the results were inconclusive with regard to HDP. Longitudinal studies that consider prospective investigation, adjustment of confounding factors and the interference of other contaminants in the exacerbation of oxidative stress in women from the preconception phase to the puerperal period should be encouraged.

Serum trace elements show association with thyroperoxidase autoantibodies in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules

Thyroid nodule (TN) has been becoming a great concern worldwide due to its high incidence. Although some studies have reported associations between trace elements exposure and the risk of TNs, the linkage was not inconclusive. The present study aimed to identify the association of selected serum trace elements (Ca, Mg, V, Fe, Co, Cu, Zn, Se, Mn and Mo) with TNs among general adults. A cross-sectional study was conducted in January 2021 in Chengdu, China. 1282 subjects completed the questionnaire and gave at least one human biological material after an overnight fast, venous blood, and urine, including 377 TN participants defined through ultrasound. Various trace elements in serum specimens were determined by inductively coupled plasma mass spectrometry. Thyroid functions were tested by chemiluminescent microparticle immunoassay (CMIA). The associations between trace elements levels and the risk of TNs were examined by restricted cubic splines (RCS) regression and bayesian kernel machine regression (BKMR) models. TNs were more common in females (P < 0.001) and in the elderly (P < 0.001) and that they were also frequently associated with fertility, marital status, annual household income, drinking, anxiety, vitamin supplement, tea consumption, hypertension and hyperlipidemia. After adjusting for confounders by a propensity score matching model, the association between trace elements concentrations and TNs risk was found to be statistically insignificant in the RCS (P for nonlinear > 0.05) and BKMR models. FT3 or T4 (total or free) increased significantly with increasing total trace elements mixture levels. In TI-RADS-4 TN subjects, TPO-Ab level increased significantly with increasing total trace elements mixture levels in the high-dose range. Ca, Zn, Mo at their 75th percentile showed positive individual effects on TPO-Ab, which was examined to be interactive. The detection of trace elements for TNs in general adults may be of no significance, but once individuals classified as TI-RADS-4 TNs are detected with abnormal TPO-Ab, Ca, Zn and Mo level are recommended to measure. The substantive association on it still needs to be continuously explored in the future.

Multiple Environmental Exposures and the Development of Hypertension in a Prospective US-Based Cohort of Female Nurses: A Mixture Analysis

We investigated the independent and joint associations between multiple environmental exposures and incident hypertension in a US nationwide prospective cohort of women: the Nurses' Health Study II. We followed 107,532 nonhypertensive participants from 1989 to diagnosis of hypertension, loss to follow-up, death, or end of follow-up in June 2019. We applied Cox proportional hazards models to assess associations of incident hypertension with time-varying residential exposure to air pollution, noise, surrounding greenness, temperature, and neighborhood socioeconomic status (nSES), adjusting for potential confounders and coexposures. We evaluated the joint association of simultaneous exposure using quantile g-computation. We observed 38,175 hypertension cases over 2,062,109 person-years. Increased hypertension incidence was consistently associated with lower nSES and higher levels of fine particles (PM2.5) and nighttime noise exposures: hazard ratio (HRs) and 95% confidence intervals (CIs) of 1.06 (1.04, 1.08), 1.04 (1.01, 1.07), and 1.01 (1.00, 1.03), respectively, per interquartile range change. Joint HR for a one-quartile change in simultaneous exposure to the mixture was 1.05 (95% CI: 1.02, 1.09), assuming additivity, or 1.13 (95% CI: 1.06, 1.20), considering potential interactions within the mixture. Hypertension prevention should focus on enhancing nSES and reducing PM2.5 and noise levels, recognizing that reducing the overall exposures may yield additional benefits.

Associations between seminal plasma metals/metalloids and semen quality: A cross-sectional study

Exposure to metals/metalloids is reported to potentially influence semen quality. While most studies have focused on single metal impacts, the link between exposure to multiple metals and semen quality has remained less explored. The study aimed to investigate the effects of both individual and mixed metal/metalloid exposure on semen quality. A total of 330 men were recruited from three reproductive centers in eastern China. Seminal plasma levels of 25 metals/metalloids and sperm parameters were determined. We used the Generalized Linear Model (GLM) and Restricted Cubic Spline (RCS) to assess the relationships between single metals/metalloids and semen quality. The weighted quantile sum (WQS) models were then applied to evaluate the combined effect of all these metals/metalloids. We observed positive associations of exposure to lithium (Li), zinc (Zn), and magnesium (Mg) with an increased risk of below reference values for progressive motility and total motility using a logistic regression model (P < 0.05). Additionally, our results also revealed a significant inverse relationship between aluminum (Al) and both sperm concentration and count, while cobalt (Co) demonstrated a positive association with sperm concentration (P < 0.05). Notably, the WQS model indicated a significant positive association between exposure to metal/metalloid mixtures and the risk of abnormal progressive motility (OR: 1.57; 95%CI: 1.10, 2.24) and abnormal total motility (OR: 1.53; 95%CI: 1.06, 2.19), with this association primarily driven by Li, Mg, and Zn. In summary, our findings indicate that exposure to metal/metalloid mixtures might have an adverse effect on semen quality.

Comparison of zinc levels in mothers with and without abortion: A systematic review and meta-analysiss

Introduction

Zinc is an essential trace element involved in different physiological functions. During pregnancy, it plays a crucial role in healthy embryogenesis. Abortion is the most severe problem associated with early pregnancy complications. This study aims to compare the levels of Zn in mothers with and without abortion.

Methods

This study is a systematic review and meta-analysis of studies published between 1980 and 2022 in PubMed, Science Direct, Pro Quest, Wiley, Web of Science, and Scopus databases. The search was conducted using both main and Mesh keywords, specifically targeting terms related to abortion, pregnancy loss, and zinc. Heterogeneity in the studies included in the meta-analysis was evaluated using statistical tests such as the chi-square test, I2, and forest plots. Publication bias was assessed using Begg's and Egger's tests. All analyses were conducted using Stata 15, and statistical significance was considered at p < 0.05.

Results

In general, nine studies were included in this analysis. Based on the results of the meta-analysis, the mean difference in the Zn level between mothers with and without abortion is equal to 193.18 (95 % CI; 107.11 to 279.25, P ≤ 0.001). In other words, the level of Zn in the group of mothers without abortion is 193 units higher than the group of mothers with abortion. The investigation into the comparison of Zn levels in mothers with and without abortion did not reveal any indication of publication bias according to both Begg's test (P-value = 0.858) and Egger's test (P-value = 0.270).

Conclusion

the study findings indicate a significant association between lower levels of Zn in mothers with abortion compared to mothers without abortion. This suggests that a higher level of Zn may have a preventive effect on the occurrence of abortion in pregnant women. The data also highlights the positive role of trace metals, particularly Zn, in influencing pregnancy outcomes and suggests that maintaining adequate levels of Zn may reduce the likelihood of abortion occurrence, along with other contributing factors. It is important to note that further research, including prospective cohort and experimental studies, is needed to provide more substantial evidence and strengthen these findings.

Cholesterol mediates the effects of single and multiple environmental phenols in urine on obesity

BACKGROUND

Overweight and obesity are among the leading chronic diseases worldwide. Environmental phenols have been renowned as endocrine disruptors that contribute to weight changes; however, the effects of exposure to mixed phenols on obesity are not well established.

METHODS

Using data from adults in National Health and Nutrition Examination Survey, this study examined the individual and combined effects of four phenols on obesity. A combination of traditional logistic regression and two mixed models (weighted quantile sum (WQS) regression and Bayesian kernel-machine regression (BKMR)) were used together to assess the role of phenols in the development of obesity. The potential mediation of cholesterol on these effects was analyzed through a parallel mediation model.

RESULTS

The results demonstrated that solitary phenols except triclosan were inversely associated with obesity (P-value < 0.05). The WQS index was also negatively correlated with general obesity (β: 0.770, 95% CI: 0.644-0.919, P-value = 0.004) and abdominal obesity (β: 0.781, 95% CI: 0.658-0.928, P-value = 0.004). Consistently, the BKMR model demonstrated the significant joint negative effects of phenols on obesity. The parallel mediation analysis revealed that high-density lipoprotein mediated the effects of all four single phenols on obesity, whereas low-density lipoprotein only mediated the association between benzophenol-3 and obesity. Moreover, Cholesterol acts as a mediator of the association between mixed phenols and obesity. Exposure to single and mixed phenols significantly and negatively correlated with obesity. Cholesterol mediated the association of single and mixed environmental phenols with obesity.

CONCLUSIONS

Assessing the potential public health risks of mixed phenols helps to incorporate this information into practical health advice and guidance.

Association between exposure to multiple metals and stress urinary incontinence in women: a mixture approach

There is limited evidence linking exposure to heavy metals, especially mixed metals, to stress urinary incontinence (SUI). This study aimed to explore the relationship between multiple metals exposure and SUI in women. The data were derived from the National Health and Nutrition Examination Survey (NHANES), 2007-2020. In the study, a total of 13 metals were analyzed in blood and urine. In addition, 5155 adult women were included, of whom 2123 (41.2%) suffered from SUI. The logistic regression model and restricted cubic spline (RCS) were conducted to assess the association of single metal exposure with SUI risk. The Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) were used to estimate the combined effect of multiple metals exposure on SUI. First, we observed that blood Pb, Hg and urinary Pb, Cd were positively related to SUI risk, whereas urinary W was inversely related by multivariate logistic regression (all p-FDR < 0.05). Additionally, a significant non-linear relationship between blood Hg and SUI risk was observed by RCS analysis. In the co-exposure models, WQS model showed that exposure to metal mixtures in blood [OR (95%CI) = 1.18 (1.06, 1.31)] and urine [OR (95%CI) = 1.18 (1.03, 1.34)] was positively associated with SUI risk, which was consistent with the results of BKMR model. A potential interaction was identified between Hg and Cd in urine. Hg and Cd were the main contributors to the combined effects. In summary, our study indicates that exposure to heavy metal mixtures may increase SUI risk in women.

The joint effect of cumulative doses for outdoor air pollutants exposure in early life on asthma and wheezing among young children

BACKGROUND

Constrained by no proper way to assess cumulative exposure, the joint effect of air pollution cumulative exposure doses on childhood asthma and wheezing (AW) was not understood.

OBJECTIVE

To assess the association between cumulative exposure to multiple air pollutants in early life and childhood AW.

METHODS

We designed a nested case-control study based on the birth cohort in Jinan City. Children with AW followed up within 2 years after birth were treated as cases, and non-cases in this cohort were treated as the control source population, and the propensity score matching method was used to match each case to 5 controls. We calculated the individual cumulative outdoor exposure doses for each period using an inverse distance weighted model, alongside the complex Simpson's formula, accounting for outdoor time and respiratory volume. The Least absolute shrinkage and selection operator (Lasso) regression was performed to screen for covariates. To analyze the joint effects of pollutants, we employed the weighted quantile sum (WQS) regression model in conjunction with conditional logistic regression.

RESULTS

84 cases and 420 controls were included in this study. The odds ratio (OR) with 95% confidence interval (CI) of the impact of cumulative exposure (mg/m3) after birth on childhood AW was 1.78 (1.15-2.74) for SO2, 1.69 (1.11-2.57) for NO2, and 1.65 (1.09-2.52) for PM2.5, respectively. Furthermore, with each 25th percentile increase in the WQS index, the overall risk of cumulative doses for six pollutants exposure after birth on AW increased by an adjusted OR of 1.10 (1.03, 1.18), and SO2, PM2.5, and NO2 contributed the most to the WQS index. However, no statistically significant association was found between cumulative exposure to all pollutants before birth and childhood AW.

CONCLUSIONS

There was a joint effect of the cumulative exposure dose of outdoor air pollutants after birth on AW in children aged 0-2 years. And traffic-related pollutants (SO2, PM2.5, and NO2) make a greater contribution to the joint effect.

Association between Mediterranean diet and metal mixtures concentrations in pregnant people from the New Hampshire Birth Cohort Study

Diet is a primary source of nutrients but also toxic metal exposure. In pregnancy, balancing essential metal exposure while reducing non-essential ones is vital for fetal and maternal health. However, the effect of metal mixtures from diets like the Mediterranean, known for health benefits, remains unclear. This study aimed to explore the association between Mediterranean diet adherence and metals exposure, both individually and as mixtures. The study involved 907 pregnant participants from the New Hampshire Birth Cohort Study. We calculated the relative Mediterranean diet score (rMED) through a validated food frequency questionnaire, which includes 8 traditional Mediterranean dietary components. Also, at ~24-28 weeks of gestation, we used ICP-MS to measure speciation of Al, Cd, Co, Cu, Fe, Hg, Mo, Ni, Sb, Se, Sn, Zn, and As in urine, as well as Pb, Hg, As, Ni, and Se in toenails. We used multiple linear regression and Weighted Quantile Sum regression to analyze the association between rMED and metal mixtures. The models were adjusted for age, pre-pregnancy BMI, smoking during pregnancy, and educational level. High adherence to the Mediterranean diet was associated with increased urinary Al (® = 0.26 (95 % confidence interval (CI) = 0.05; 0.46)), Cd (β = 0.12 (95%CI = 0.00; 0.24)), Mo (β = 0.10 (95%CI = 0.00; 0.20)), and AsB (β = 0.88 (95%CI = 0.49; 1.27)) as well as toenail Hg (β = 0.44 (95%CI = 0.22; 0.65)), Ni (β = 0.37 (95%CI = 0.06; 0.67)), and Pb (β = 0.22 (95%CI = 0.03; 0.40)) compared to those with low adherence. The intake of fruits and nuts, fish and seafood, legumes, cereals, meat, and olive oil were found to be related to the metal biomarkers within the rMED. In conclusion, the Mediterranean diet enhances essential metal intake but may also increase exposure to harmful ones.

Multivitamin consumption and childhood asthma: a cross-sectional study of the NHANES database

BACKGROUND

Dietary intakes of vitamins are associated with asthma. However, previous studies mainly explored the association between a single vitamin intake and asthma, which did not take the multivitamins into consideration. Herein, this study aims to explore the overall effect of dietary multivitamins consumption on childhood asthma.

METHODS

Data of children and adolescents (aged 2-17 years old) were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2015-2018 in this cross-sectional study. Weighted univariate logistic regression analysis was used to screen covariates. The association between multivitamins (including vitamin A, C, D, E, B1, B2, B6, B12, K, niacin, folic acid, and choline) and childhood asthma was explored using univariate and multivariate logistic regression analyses. The evaluation indexes were odds ratio (OR) and 95% confidence interval (CI). We further introduced the Bayesian kernel machine regression (BKMR) to assess the joint effect of the twelve vitamins on childhood asthma, the impact of an individual vitamin as part of a vitamin mixture, and the potential interactions among different vitamins.

RESULTS

Among 4,715 eligible children and adolescents, 487 (10.3%) had asthma. After adjusting for covariates including race, family history of asthma, pregnant smoking, BMI Z-score, energy intake, breast feeding, and low birth weight, we found that for each 1-unit increase in vitamin K consumption, the odds of childhood asthma decreased 0.99 (P=0.028). The overall effect analysis reported a trend of negative relationship between the multivitamins and childhood asthma, especially at the 75th percentile and over. According to the BKMR models, when other vitamins are fixed at the median level, the odds of childhood asthma increased along with the elevated vitamin D (VD) and vitamin B2 (VB2), whereas along with the depressed vitamin C (VC). In addition, no potential interaction has been found between every two vitamins of multivitamins on childhood asthma.

CONCLUSION

Among children and adolescents who have high-risk of asthma, it may be beneficial to increase dietary consumption of multivitamins. Our findings recommended that children and adolescents should increase the intake of VC-rich foods, whereas control the dietary consumption of VD and VB2 in daily life.

Exposure to metal mixtures and adverse pregnancy and birth outcomes: A systematic review

BACKGROUND

Prenatal exposure to metal mixtures is associated with adverse pregnancy and birth outcomes like low birth weight, preterm birth, and small for gestational age. However, prior studies have used individual metal analysis, lacking real-life exposure scenarios.

OBJECTIVES

This systematic review aims to evaluate the strength and consistency of the association between metal mixtures and pregnancy and birth outcomes, identify research gaps, and inform future studies and policies in this area.

METHODS

The review adhered to the updated Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) checklist, along with the guidelines for conducting systematic reviews and meta-analyses of observational studies of etiology (COSMOS-E). Our data collection involved searching the PubMed, MEDLINE, and SCOPUS databases. We utilized inclusion criteria to identify relevant studies. These chosen studies underwent thorough screening and data extraction procedures. Methodological quality evaluations were conducted using the NOS framework for cohort and case-control studies, and the AXIS tool for cross-sectional studies.

RESULTS

The review included 34 epidemiological studies, half of which focused on birth weight, and the others investigated neonate size, preterm birth, small for gestational age, miscarriage, and placental characteristics. The findings revealed significant associations between metal mixtures (including mercury (Hg), nickel (Ni), arsenic (As), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), zinc (Zn), barium (Ba), cesium (Cs), copper (Cu), selenium (Se), and chromium (Cr)) and adverse pregnancy and birth outcomes, demonstrating diverse effects and potential interactions.

CONCLUSION

In conclusion, this review consistently establishes connections between metal exposure during pregnancy and adverse consequences for birth weight, gestational age, and other vital birth-related metrics. This review further demonstrates the need to apply mixture methods with caution but also shows that they can be superior to traditional approaches. Further research is warranted to deeper understand the underlying mechanisms and to develop effective strategies for mitigating the potential risks associated with metal mixture exposure during pregnancy.

Association between urinary multiple metals and platelet-related parameters: A cross-sectional study in a metal-contaminated area of China

Previous works have shown that hematological system can be affected by exposure to lead; however, the effects of multiple metals on platelets remain elusive within the population from metal-contaminated areas. Hence, the study enrolled 609 participants, with 396 from a metal-exposed area and 213 from a control area. Platelet count (PLT), mean platelet volume (MPV), thrombocytocrit (PCT), platelet to large cell ratio (P-LCR), and platelet distribution width (PDW) were selected to evaluate platelet function. Stepwise regression and Lasso regression were utilized to identify the most influential metals. Moreover, the generalized linear model (GLM), Bayesian kernel machine regression (BKMR) models, and quantile g-computation were employed to estimate the individual or combined effects associations between 12 urinary metals and platelet indices. The results revealed all metals except vanadium, copper, strontium, and molybdenum were significantly higher in the exposed group. The GLM models indicated that urinary metals, including lead, antimony, and arsenic, exhibited associations with PLT, MPV, P-LCR, and PDW. Quantile g-computation and BKMR demonstrated negative correlations between metal mixtures and MPV as well as PDW. In conclusion, the study highlights the associations between multiple metal exposures and platelet indices, suggesting that elevated levels of the metal mixture may impede platelet activation in the population in metal-contaminated areas.

Exposure to particulate matter may affect semen quality via trace metals: Evidence from a retrospective cohort study on fertile males

Particulate matter (PM) exposure may be associated with male semen quality. Besides, PM exposure induces up and down levels of trace metals in tissues or organs. The levels of trace metals in semen are critical for adverse male semen quality. This study aims to evaluate the concentrations of seminal-level trace metals in fertile men and assess its associations with PM exposure and to explore the mediation role of trace metals in seminal plasma plays in the relationship between PM exposure and semen quality. Total 1225 fertile men who participated in a cohort study from 2014 to 2016 were finally recruited. Multivariate linear regression was applied to explore associations between each two of PM exposure, trace metals and semen parameters. 1-year PM2.5 and PM10 exposure levels were positively associated with arsenic (As), mercury (Hg), lanthanum (La), praseodymium (Pr), neodymium (Nd) but negatively associated with vanadium (V), magnesium (Mg), strontium (Sr), barium (Ba) in semen. It was also found that most of the elements were associated with total sperm number, followed by sperm concentration. Redundancy analysis (RDA) also determined several strong positive correlations or negative correlations between 1-year PM exposure and trace metals. Mediation analysis found that trace metals had a potentially compensatory or synergetic indirect effect on the total effect of the association between 1-year PM exposure and semen quality. The retrospective cohort study provides long-term PM exposure that may cause abnormal semen quality by affecting seminal plasma element levels.

Combined exposure to multiple essential elements and cadmium at early pregnancy on gestational diabetes mellitus: a prospective cohort study

Background

Minerals and trace elements were involved in the pathogenesis and progression of diabetes. However, the association of mixed exposure to essential elements and toxic elements with gestational diabetes mellitus (GDM) is poorly understood.

Objective

This study aims to examine the associations between serum calcium (Ca), iron (Fe), zinc (Zn), copper (Cu), magnesium (Mg), and cadmium (Cd) concentrations in early pregnancy and GDM risk in Chinese pregnant women.

Method

A total of 1,168 pregnant women were included in this prospective cohort study. The concentrations of serum elements were measured using the polarography method before 14 gestational weeks and an oral glucose tolerance test was conducted at 24-28 gestational weeks to diagnose GDM. Binary logistic regression analysis and restricted cubic spline were applied to evaluate the association between serum individual element and GDM. Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression were used to assess the associations between mixed essential elements and Cd exposure and GDM risk.

Results

The mean concentrations of Zn (124.65 vs. 120.12 μmol/L), Fe (135.26 vs. 132.21 μmol/L) and Cu (23.33 vs. 23.03 μmol/L) in the GDM group were significantly higher than those in the control group. Single-element modeling results suggested that second and fourth-quartile maternal Zn and Fe concentration, third and fourth-quartile Cu concentration and fourth-quartile Ca concentration were associated with an increased risk of GDM compared to first-quartile values. Restricted cubic spline analysis showed U-shaped and non-linear relationships between Cd and GDM. According to the BKMR models and WQS analyses, a six-element mixture was significantly and positively associated with the risk of GDM. Additionally, Cd, Zn, and Cu contributed the most strongly to the association.

Conclusion

Serum Zn, Cu, Fe, and Ca exposure during early pregnancy showed a positive association with GDM in the individual evaluation. The multiple-evaluation showed that high levels of elements mixture, particularly Cd, Zn, and Cu, may promote the development of GDM.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study, 2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL values of women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study found that exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Exposure of Reproductive-Aged Women to Multiple Metals and Its Associations with Unexplained Recurrent Miscarriage

Exposure to heavy metals exerts toxic effects on female reproduction and embryo development. This study examined the exposure of patients with unexplained recurrent miscarriage (uRM) to multiple metals and the correlations among exposures to different metals. A total of 275 participants were enrolled, including 43 healthy women without previous miscarriage (the control group) and 232 uRM women (the case group); among these uRM women, 159 had two miscarriages (2M), 42 had three miscarriages (3M) and 31 had four or more miscarriages (≥4M). A total of 22 elements were measured in serum samples via inductively coupled plasma-mass spectrometry. The levels of calcium (104.37 mg/L vs. 92.65/93.02/92.61/92.47 mg/L) and selenium (131.85 µg/L vs. 117.80/118.04/115.88/124.35 µg/L) were higher in the controls than in the total uRM group and the 2M, 3M and ≥4M subgroups. The level of vanadium was significantly lower in the controls than in the total uRM group (0.15 µg/L vs. 0.23 µg/L), and the level of lead was lower in the controls than that in the total uRM group and the 2M, 3M and ≥4M subgroups (0.01 µg/L vs. 0.28/0.18/0.63/0.34 µg/L). After adjusting for age, body mass index and education level, calcium and selenium exposure were consistently negatively associated with miscarriage, while lead exposure was positively associated with miscarriage. In addition, the correlations among exposures to different metals slightly differed between the control and uRM groups. Therefore, changes in some metal elements in the blood might be related to the risk of uRM.

Maternal urinary metal(loid)s and risk of preterm birth: A cohort study in the Tibetan Plateau

Maternal metal(loid)s exposure has been related to preterm birth (PTB), but the results are still inconclusive. Previous studies have mainly discussed the harmful metal(loid)s, neglecting beneficial ones. We examined the association of maternal metal(loid)s with PTB and gestational age (GA) in a birth cohort from the Tibetan Plateau. We measured 29 metal(loid)s in urine samples from 1081 pregnant women in the third trimester. Information regarding demographics, socioeconomic status, diet, medication, and lifestyle was collected through standardized interviews. The associations of single metal(loid)s with PTB or GA were evaluated using a generalized linear mixed-effects model or linear mixed-effects model. Elastic net and Bayesian kernel machine regressions were used to explore the joint associations. Magnesium (Mg), Copper (Cu), and Tin (Sn) were the main "harmful" metal(loid)s positively and negatively associated with PTB or GA, respectively. Mg was the dominant "harmful" metal(loid)s associated with PTB in a J-shape. A one-fold increase in Mg was associated with a 38% increased risk of PTB [OR (95% CI) = 1.38 (1.15, 1.65), PFDR＜0.05] and 0.17 weeks shortening of GA [β (95% CI) = -0.25 (-0.35, -0.14), PFDR＜0.05]. Cesium (Cs), rubidium (Rb), and Molybdenum (Mo) were the main "beneficial" metals. Cs dominated the "beneficial" associations and was negatively associated with PTB in a linear manner. A one-fold increase in Cs was associated with a 67% decreased risk of PTB [OR (95% CI) = 0.43 (0.27, 0.67), PFDR＜0.05] and 0.24 weeks of prolonged GA [β (95% CI) = 0.35 (0.13, 0.56), PFDR＜0.05]. Ethnicity and living altitude modified the association of Mg and Cu with PTB or GA. In conclusion, Maternal urinary metal(loid)s were bi-directionally associated with PTB in a population in the Tibetan Plateau. Mg and Cs were the dominant "harmful" and "beneficial" metal(loid)s, respectively.

Association between female circulating heavy metal concentration and abortion: a systematic review and meta-analysis

Objective

This study aimed to evaluate the association between blood heavy metal (zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)) concentrations and spontaneous abortion (SA) and recurrent pregnancy loss (RPL) and explore the possible endocrine dysfunction associated with it.

Methods

A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2023. The overall effects were expressed as the standard mean difference (SMD). Subgroup analysis was performed according to the type of abortion (SA or RPL). Stata 16.0 was utilized for data analysis.

Results

Based on the integrated findings, abortion women showed significantly lower Zn (SMD = -1.05, 95% CI: -1.74 to -0.36, p = 0.003) and Cu concentrations (SMD = -1.42, 95% CI: -1.97 to -0.87, p <0.001) and higher Pb (SMD = 1.47, 95% CI: 0.89-2.05, p <0.001) and Cd concentrations (SMD = 1.15, 95% CI: 0.45-1.85, p = 0.001) than normal pregnant women. Subgroup analysis showed that Zn and Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with RPL, whereas Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with SA.

Conclusion

Zn and Cu deficiencies and Pb and Cd exposure were associated with abortion. Endocrine dysfunction, such as insulin resistance, vitamin D insufficiency, and abnormal thyroid and sex hormone concentrations, is thought to be involved in heavy metal-related abortion.

Short-Term Exposure to PM2.5 and O3 Impairs Liver Function in HIV/AIDS Patients: Evidence from a Repeated Measurements Study

Studies investigating the relationship between ambient air pollutants and liver function are scarce. Our objective was to examine the associations of acute exposure to PM2.5 and O3 with levels of hepatic enzymes in people living with HIV/AIDS (PWHA). Our study involved 163 PWHA, who were evaluated for serum hepatic enzymes up to four times within a year. We extracted daily average concentrations of PM2.5, PM2.5 components, and O3 for each participant, based on their residential address, using the Tracking of Air Pollution in China database. Linear mixed-effect models were utilized to assess the associations of acute exposure to PM2.5 and O3 with hepatic enzymes. Weighted quantile sum regression models were employed to identify the major constituents of PM2.5 that affect hepatic enzymes. The percent change of aspartate aminotransferase (AST) concentration was positively correlated with a 10 µg/m3 increase in PM2.5, ranging from 1.92 (95% CI: 3.13 to 4.38) to 6.09 (95% CI: 9.25 to 12.38), with the largest effect observed at lag06. Additionally, acute O3 exposure was related to increased levels of alanine aminotransferase (ALT), AST, and alkaline phosphatase (ALP) concentrations. Co-exposure to high levels of PM2.5 and O3 had an antagonistic effect on the elevation of AST. Further analysis revealed that SO42- and BC were major contributors to elevated AST concentration due to PM2.5 constituents. A stronger association was found between O3 exposure and ALT concentration in female PWHA. Our study found that short-term exposure to PM2.5 and O3 was associated with increased levels of hepatic enzymes, indicating that PM2.5 and O3 exposure may contribute to hepatocellular injury in PWHA. Our study also found that PWHA may be more vulnerable to air pollution than the general population. These findings highlight the relationship between air pollutants and liver function in PWHA, providing a scientific basis for the implementation of measures to protect susceptible populations from the adverse effects of air pollution. A reduction in the burning of fossil fuels and reduced exposure to air pollutants may be effective hazard reduction approaches.

Maternal Exposure to Trace Elements, Toxic Metals, and Longitudinal Changes in Infancy Anthropometry and Growth Trajectories: A Prospective Cohort Study

Exploration of stage-specific effects of maternal exposure to trace elements and toxic metals on infancy continuous growth and trajectories is critical for early-life health management. Within a Chinese prospective cohort in 2014-2015, a total of 919 mother-infant pairs were included, and the urinary levels of 17 elements including vanadium (V), chromium (Cr), manganese, iron, cobalt, nickel, copper, zinc, arsenic, molybdenum, palladium, cadmium, tin, gold, mercury, thallium, and lead in early (mean: 11.9 weeks), and late pregnancy (mean: 32.4 weeks) were assessed. Standardized anthropometric assessments of infants were conducted at 1, 3, 6, 8, and 12 months of age. A three-step longitudinal and high-dimensional data analysis procedure was carried out to estimate the impacts of exposome on dynamic growth. Early-pregnancy exposures to V and Cr were positively associated with repeated measurements of length-for-age z-scores (LAZ). Six trajectories were identified based on LAZ. Maternal single exposure to V and Cr as well as mixed exposure to trace elements in early pregnancy were associated with raised odds for the high-stable group. Our results suggested positive associations between maternal trace element exposome and infancy dynamic growth. V and Cr were the key elements and the early pregnancy might be the critical window.

A New Advanced and Validated Method for the Determination of Potentially Toxic Metals and Trace and Ultra-Trace Elements in Peritoneal Fluid to Assess the Health Risks of Women with Gynecological Pathologies

Toxic metals found in the environment have been linked to female infertility and gynecological illnesses. Reliable analytical methods, such as inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), are necessary to determine the elemental composition of biological samples. Currently, the multielemental profile of peritoneal fluid (PF) samples has not yet been established. Due to the complexity of the PF matrix, an ICP-MS/MS-based method has been optimized to mitigate matrix effects and spectral interferences. A dilution factor of 1:4 was the best option to mitigate matrix effects while keeping sensitivity at an appropriate level. A collision gas (He) was useful to lower the extent of spectral interferences for ⁵⁶Fe, ⁵²Cr, ⁶³Cu, and ⁶⁸Zn. An intermediate validation test was performed to evaluate accuracy, achieving recoveries ranging from 90 to 110%. The method was validated in terms of intermediate precision, reproducibility, and trueness, with an expanded uncertainty lower than 15%. Afterward, it was applied to perform the multielemental analysis of 20 PF samples. The concentrations for major analytes were up to 151 µg L^-1. Meanwhile,²⁰⁹Bi, ¹¹¹Cd, ⁵²Cr, ⁵⁵Mn, ⁹⁵Mo, ⁶⁰Ni, ²⁰⁸Pb, ¹¹⁸Sn, and ⁵¹V were present at concentrations included within the 1-10 µg L^-1 range, while ⁵⁹Co and ¹³⁹La were found at concentrations below 1 µg L^-1.

Prenatal Exposure to Legacy and Alternative Per- and Polyfluoroalkyl Substances and Neuropsychological Development Trajectories over the First 3 Years of Life

The neurotoxic effects of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) on offspring animals are well-documented. However, epidemiological evidence for legacy PFAS is inconclusive, and for alternative PFAS, it is little known. In this investigation, we selected 718 mother-child pairs from the Chinese Maoming Birth Cohort Study and measured 17 legacy and alternative PFAS in the third-trimester serum. Neuropsychological developments (communication, gross motor function, fine motor function, problem solving ability, and personal-social skills) were assessed at 3, 6, 12, 18, 24, and 36 months using the Ages and Stages Questionnaires 3rd edition. Trajectories of each subscale were classified into persistently low and persistently high groups via group-based trajectory modeling. Logistic regression and grouped weighted quantile sum were fitted to assess the potential effects of individual PFAS and their mixtures, respectively. Higher linear PFHxS levels were associated with elevated odds for the persistently low trajectories of communication (OR = 1.73; 95% CI: 1.12, 2.66) and problem solving ability (OR = 2.11; 95% CI: 1.14, 3.90). Similar findings were observed for linear PFOS, 1m-PFOS, PFDA, PFDoDA, PFUnDA, and legacy PFAS mixture. However, no association was observed for alternative PFAS and their mixture. We provided insights into the longitudinal links between prenatal legacy/alternative PFAS exposure and neuropsychological development trajectories over the first 3 years of life.

High-temperature exposure and risk of spontaneous abortion during early pregnancy: a case-control study in Nanjing, China

As one of the most common complications of early pregnancy, spontaneous abortion is associated with environmental factors, but reports estimating the effect of ambient temperature on spontaneous abortion are still inconclusive. Herein, a case-control study (1002 cases and 2004 controls) in Nanjing, China, from 2017 to 2021 was conducted to evaluate the association between temperature exposure and the risk of spontaneous abortion by using distributed lag nonlinear model (DLNM). As a result, daily mean temperature exposure and early spontaneous abortion showed a nonlinear relationship in 14-day lag periods. Moreover, taking the median temperature (17 °C) as a reference, gradually increased positive effects of high temperature on spontaneous abortion could be found during the 4 days prior to hospitalization, and the highest odds ratio (OR) of 2.07 (95% confidence interval (CI): 1.36, 3.16) at extremely hot temperature (33 °C) was observed at 1 lag day. The results suggested that high-temperature exposure in short times during early pregnancy might increase the risk of SAB. Thus, our findings highlight the potential risk of short-term high-temperature exposure during early pregnancy, and more evidence was given for the effects of climate change on maternal health.

Short-term associations of PM2.5 and PM2.5 constituents with immune biomarkers: A panel study in people living with HIV/AIDS

Studies on associations of fine particulate matter (PM_2.5) with immunity in people living with HIV/AIDS (PLWHA) were absent. We aimed to explore whether changes of immune biomarkers were associated with short-term exposure to PM_2.5 in PLWHA. Based on a panel study in Wuhan, we selected 163 PLWHA as participants with up to 4 repeated visits from March 2020 to January 2021. Immune biomarkers, including CD4⁺T cell count, CD8⁺T cell count, HIV viral load (VL) and CD4⁺T/CD8⁺T ratio were tested for all participants at each visit. Residential exposures of PM_2.5 and PM_2.5 constituents for each participant were assessed using spatial-temporal models. Linear mixed-effect models and general linear mixed models were applied to evaluate the associations between PM_2.5 and immune biomarkers. To estimate the combined effect of PM_2.5 constituents, weighted quantile sum regression and Bayesian kernel machine regression were employed. Each 10 μg/m³ increase of 7-day average PM_2.5 concentrations was associated with an 8.75 cells/mm³ (95%CI: -15.55, -1.98) decrease in CD4⁺T cell count and a 92% (OR: 1.92, 95%CI: 1.43, 2.58) increased odds ratio of detectable HIV VL. However, the odds ratio of inverted CD4⁺T/CD8⁺T was only positively associated with PM_2.5 concentrations at lag2 day (OR:1.27, 95%CI:1.02, 1.57). CD4⁺T may be a potential mediator between PM_2.5 and detectable HIV VL with 3.83% mediated proportion. Besides, the combined effect of PM_2.5 chemical constituents indicated that NO₃^- and SO₄^2- were the main constituents in reducing CD4⁺T cell count and increasing odds ratio of detectable HIV VL. Our finding revealed that short-term exposure to PM_2.5 was negatively associated with CD4⁺T cell count but positively related to the odds ratio of detectable HIV VL in PLWHA. This research may provide new evidence in associations between PM_2.5 and immune biomarkers as well as improving prognosis of PLWHA.

Association between combined exposure to plasma heavy metals and dyslipidemia in a chinese population

BACKGROUND

Exposure to heavy metals in the environment is widespread, while the relationship between combined exposure to heavy metals and dyslipidemia is unclear.

METHODS

A cross-sectional study was performed, and 3544 participants aged 30 years or older were included in the analyses. Heavy metal concentrations in plasma were based on inductively coupled plasma‒mass spectrometry. The relationship between heavy metals and dyslipidemia was estimated by logistic regression. BKMR was used to evaluate metal mixtures and their potential interactions.

RESULTS

In logistic regression analysis, participants in the fourth quartile of Fe and Zn (Fe > 1352.38 µg/L; Zn > 4401.42 µg/L) had a relatively higher risk of dyslipidemia (Fe, OR = 1.13, 95% CI: 0.92,1.38; Zn, OR = 1.30, 95% CI: 1.03,1.64). After sex stratification, females in the third quartile of plasma Zn (1062.05-4401.42 µg/L) had a higher relative risk of dyslipidemia (OR = 1.75, 95% CI: 1.28, 2.38). In BKMR analysis, metal mixtures were negatively associated with dyslipidemia in females when all metal concentrations were above the 50th percentile. In the total population (estimated from 0.030 to 0.031), As was positively associated with dyslipidemia when other metals were controlled at the 25th, 50th, or 75th percentile, respectively, and As was below the 75th percentile. In females (estimated from - 0.037 to -0.031), Zn was negatively associated with dyslipidemia when it was above the 50th percentile.

CONCLUSION

This study indicated that As was positively associated with dyslipidemia and that Zn may be negatively associated with dyslipidemia in females. Combined metal exposure was negatively associated with dyslipidemia in females. Females with low plasma Zn levels are more likely to develop dyslipidemia and should receive more clinical attention in this population.

An Evaluation of Exposure to 18 Toxic and/or Essential Trace Elements Exposure in Maternal and Cord Plasma during Pregnancy at Advanced Maternal Age

Pregnant women of advanced maternal age (AMA) are vulnerable to exposure to the surrounding environment. Assessment of trace elements in pregnant women living in specific areas is important for biomonitoring. However, exposure levels and variation patterns during pregnancy remains controversial and attracts extensive public concern. Therefore, we aimed to evaluate exposure of 18 toxic and/or essential trace elements in maternal plasma and in paired cord plasma during pregnancy at AMA. A total of 48 pregnant women of AMA were recruited in Peking University Third Hospital from 2018 to 2021. Eighteen elements found in maternal plasma during the 1st, 2nd, or 3rd trimester of pregnancy and paired cord plasma were measured by 7700x ICP-MS (Agilent Technologies, Palo Alto, CA, USA) and Elan DRC type II ICP-MS (The Perkin-Elmer Corporation, Waltham, MA USA). Concentrations of Pb, Se, Fe, Zn, and Mo all decreased during pregnancy, while Cu increased. Interestingly, concentrations of Rb decreased initially but then increased. Elements as Al, Co, Se, Cu, and Ni showed significantly lower levels in cord than in maternal plasma, while elements as Sr, Fe, Rb, Mn and Zn displayed significantly higher levels in cord than in maternal plasma. Moreover, positively- interacted clusters were found in Ni-Co-Cu-Al-Rb-Zn and Zn-Mn-Al-Pb in maternal blood. Similar positively-interacted clusters were found in Zn-Ni-Co, Zn-Ni-Fe, Mn-Al-Pb, Fe-Pb-Mn, Fe-Ni-Cu, and Rb-Cu-Sb-Fe-Mn in cord plasma. Furthermore, correlations between paired maternal and cord blood samples for As, Sr, and Mo were statistically significant, indicating that the fetus burden may reflect maternal exposure to some extent. Admittedly, levels of toxic and essential elements in our cohort study were comparatively lower than those in the scientific literature.

Urinary paraben derivatives in pregnant women at three trimesters: Variability, predictors, and association with oxidative stress biomarkers

Exposure to parabens has been shown to increase oxidative stress, which has a vital impact on the development of numerous diseases. However, few studies reported the effects of the paraben derivatives on oxidative stress, particularly among pregnant women. This study, using repeated measurements, aimed to understand the exposure profiles of urinary paraben derivative concentrations and their relationships with oxidative stress biomarkers (OSBs). A total of 861 pregnant women, who provided spot urine samples at three trimesters, were included, and 2583 urine samples were used to measure four paraben derivatives [p-hydroxybenzoic acid (p-HB), 3,4-dihydroxybenzoic acid (3,4-DHB), methyl protocatechuate, and ethyl protocatechuate], four parabens (methyl, ethyl, propyl, and butyl), and three OSBs [8-hydroxy-2'-deoxyguanosine (for DNA), 8-hydroxyguanosine (for RNA), and 4-hydroxy nonenal mercapturic acid (for lipid)]. Pregnant women were extensively exposed to parabens and paraben derivatives with detection frequencies (DFs) of 86.1%-100%, except for butylparaben with a DF of 14.9%. p-HB and 3,4-DHB had relatively high urinary concentrations (specific gravity-adjusted median values: 1394 and 74.5 ng/mL, respectively). Low reproducibility in paraben derivatives was found across the three trimesters. Sampling season, pre-pregnancy body mass index, and infant sex were predictors of some paraben derivatives/parabens. Linear mixed model analyses showed that all target compounds (if DF > 50%) were associated with increases in all the selected OSBs, where the percent change in OSBs with an interquartile range increase in paraben concentration ranged from 9.85% to 24.7%, while those in paraben derivative concentration ranged from 13.8% to 72.1%. Weighted quantile sum model showed that joint exposure was significantly associated with increased OSBs, and paraben derivatives were stronger contributors to OSBs compared with parabens. Overall, urinary paraben derivatives were associated with increased oxidative stress of nucleic acids and lipid in pregnant women.

A Global Perspective of Correlation Between Maternal Copper Levels and Preeclampsia in the 21st Century: A Systematic Review and Meta-Analysis

Background:

Preeclampsia (PE) is a common multi-system disorder in pregnancy and a major cause of maternal and perinatal morbidity and mortality globally. Copper is a crucial micronutrient for human health.

Methods

A systematic review was performed according to Preferred Reporting Item for Systematic Reviews and Meta-analysis (PRISMA) guidelines to synthesize the best available evidence regarding the correlation between maternal copper levels and PE from women with different geographical and economic backgrounds.

Results

A total of 34 studies containing 2,471 women with PE and 2,888 healthy pregnant controls across 16 countries were included for research. All studies were systematically reviewed and assessed with the Newcastle-Ottawa Scale (NOS), The Agency of Healthcare for Research and Quality (AHRQ) assessment tools according to the study types. Globally, there was no significant difference in maternal serum copper levels between women with PE and control (Mean difference 5.46, 95% CI −9.63, 20.54). Sub-group analysis from geographical and economic perspectives revealed contrasting results. In conclusion, copper is associated with PE, but the levels of copper leading to increased risk of PE varied across regions and economic development.

Conclusions

The deranged maternal copper levels are correlated with risks of PE, but it presents variously across different geographical and economic contexts.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=306536. Identifier: CRD42022306536.