Barium exposure increases the risk of congenital heart defects occurrence in offspring

Metal stannum exposure increases the risk of congenital heart defects occurence in offspring: A case-control study in Lanzhou

BACKGROUND

The purpose of this study was to analyse the association between stannum exposure during pregnancy and congenital heart diseases in offspring.

METHODS

Based on a prospective birth cohort study conducted in Gansu Maternal and Child Health Hospital from 2010 to 2012, 14,359 pregnant women were followed up using a nested case-control study method. 97 pregnant women whose offspring were diagnosed with CHDs were used as the case group, and 194 pregnant women whose offspring did not suffer from congenital heart diseases were used as the control group in a ratio of 1:2 according to their age and place of birth. Inductively coupled plasma mass spectrometry was used to determine elemental stannum in blood samples from pregnant women hospitalized for delivery and in fetal cord blood samples. Multifactorial logistic regression analysis was used to assess the association between stannum and offspring CHDs.

RESULTS

There was a moderate positive correlation between the concentration of stannum in pregnant women's blood and that in umbilical cord blood. A higher concentrations of maternal blood stannum level was associated with a greater risk of CHDs (aOR 3.409, 95%CI 1.785-6.826), isolated CHDs (aOR 4.044, 95%CI 1.803-9.070), multiple CHDs (aOR 2.625, 95%CI 1.137-6.061), patent ductus arteriosus (aOR 2.882, 95%CI 1.443-5.756), atrial septal defects (aOR 3.067, 95%CI 1.406-6.690), ventricular septal defects (aOR 7.414, 95%CI 1.414-38.874). There was a correlation between the maternal and cord blood sample suggesting stannum crosses the placenta.

A Systematic Literature Review on the Association Between Toxic and Essential Trace Elements and the Risk of Orofacial Clefts in Infants

Orofacial clefts (OFCs) have been linked to various toxic and essential trace elements (TETEs) worldwide. However, review estimation is absent. Therefore, addressing the hypothesis that TETEs are associated with OFCs is the main area of this review. A systematic literature search was conducted using electronic databases through PubMed, Web of Science, Scopus, Science Direct, and Google Scholar between 2004 and August 2022. The "AND" and "OR" operators were used to make our search results inclusive and restrictive as follows: ("Toxic element*" OR "Heavy metal*") AND ("Toxic element*" OR "Lead OR Arsenic OR Mercury*")) AND ("Essential trace element*" OR "Zinc OR Selenium OR Copper*")) AND ("Orofacial cleft*" OR "Cleft lip*" OR "Cleft palate*") AND ("Infant*" OR "Newborn*" OR "Neonate*")). The presence of toxic elements was linked to the development of OFCs. The results showed that higher levels of toxic elements in various biological sample types were related to increased risks for OFCs. Increased concentrations of essential trace elements (ETEs) lowered the risk of OFCs. Maternal consumption of diets rich in ETEs, including zinc (Zn), selenium (Se), copper (Cu), cobalt (Co), and molybdenum (Mo), was linked to a more pronounced reduction in the risk of OFCs. Based on the findings, it is acceptable to infer that maternal exposure to toxic elements, whether through environmental contaminants or dietary sources, was associated with an elevated risk of OFCs. Furthermore, the study revealed that ETEs exhibited a potential protective role in reducing the incidence of OFCs. This observation highlights the importance of reducing exposure to toxic elements during pregnancy and suggests that optimizing maternal intake of ETEs could be an effective preventive strategy.

Toxic elements identified in breast milk of mothers residing in water contaminated region of Sindh and their impact on infants' growth patterns: A case-control study

Breast milk is a vital source of nutrition for breastfed infants, providing essential nutrients and elements but, in some cases, toxic ones. This is the first case-control study that investigated the elemental profile of breast milk samples collected from mothers residing in Matiari (Sindh), a region with insufficient industrial waste management, and its potential impact on infants' anthropometrics. Precisely, 62 milk samples, including 42 cases and 20 controls, were analyzed using the ICP-MS technique. Overall, six elements showed significance between the two groups, arsenic (As) was present at 0.68 μg/L in cases and absent in controls, while lead (Pb) exhibited elevated concentrations in the case group at 4.56 μg/L compared to 0.25 μg/L in controls, well-known for their toxicity. Barium (Ba) and manganese (Mn) levels were also higher in cases, associated with reported health effects on child well-being. Essential elements molybdenum (Mo) and selenium (Se) were higher in the controls. Furthermore, the association of these metals with the child growth standards as per WHO guidelines was calculated. Linear regression analysis revealed As negatively associated with WAZ and WHZ scores, while Mo was positively associated with WAZ, WHZ, and HAZ scores. These findings highlight serious health concerns in the region, where toxic elements pervade drinking water and food sources. Immediate actions are imperative to maintain the wellness of future generations.

Exposure to Endocrine-Disrupting Chemicals and Congenital Heart Diseases: The Pooled Results Based on the Current Evidence

The relationships between maternal exposure to endocrine-disrupting chemicals (EDCs) and congenital heart diseases (CHD) are not elucidated yet. The exposure levels of EDCs are generally estimated based on self-reported questionnaires or occupational exposure evaluations in the literature. Therefore, a study based on epidemiological data from human biospecimens is required to provide stronger evidence between maternal exposure to EDC and CHD. Embase, Pubmed, Scopus, and the Cochrane Library databases were searched for related research which provided risk estimates regarding the relationships between maternal EDC exposure and CHD in human offspring. Baseline characteristics and outcomes of CHD were extracted from each included study. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled to calculate the overall estimates of CHD. Subgroup and meta-regression analyses were performed to identify the sources of heterogeneity. Bootstrapping techniques were used in analyses where several studies originated from a similar population. A total of seventeen studies were involved in the meta-analyses. Maternal EDC exposure was significantly related to CHD in offspring (OR 2.15; 95%CI 1.64 to 2.83). EDC exposure was significantly associated with septal defects (OR 2.34; 95%CI 1.77 to 3.10), conotruncal defects (OR 2.54; 95%CI 1.89 to 3.43), right ventricular outflow tract obstruction (OR 2.65; 95%CI 1.73 to 4.07), left ventricular outflow tract obstruction (OR 3.58; 95%CI 2.67 to 4.79), anomalous pulmonary venous return (OR 2.31; 95%CI 1.34 to 4.00), and other heart defects (OR 2.49; 95%CI 1.75 to 3.54). In addition, maternal exposure to heavy metals, which included lead (OR 2.19; 95%CI 1.29 to 3.71), cadmium (OR 1.81; 95%CI 1.28 to 2.56), mercury (OR 2.23; 95%CI 1.13 to 4.44), and manganese (OR 2.65; 95%CI 1.48 to 4.74), increased risks for CHD significantly. In conclusion, based on the latest evidence, maternal EDC exposure may increase CHD risks in human offspring, especially in heavy metal exposure conditions.

Placental levels of essential and non-essential trace element in relation to neonatal weight in Northwestern Spain: application of generalized additive models

Adequate gestational progression depends to a great extent on placental development, which can modify maternal and neonatal outcomes. Any environmental toxicant, including metals, with the capacity to affect the placenta can alter the development of the pregnancy and its outcome. The objective of this study was to correlate the placenta levels of 14 essential and non-essential elements with neonatal weight. We examined relationships between placental concentrations of arsenic, cadmium, cobalt, copper, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, selenium, strontium, and zinc from 79 low obstetric risk pregnant women in Ourense (Northwestern Spain, 42°20'12.1″N 7°51.844'O) with neonatal weight. We tested associations between placental metal concentrations and neonatal weight by conducting multivariable linear regressions using generalized linear models (GLM) and generalized additive models (GAM). While placental Co (p = 0.03) and Sr (p = 0.048) concentrations were associated with higher neonatal weight, concentrations of Li (p = 0.027), Mo (p = 0.049), and Se (p = 0.02) in the placenta were associated with lower newborn weight. Our findings suggest that the concentration of some metals in the placenta may affect fetal growth.

Exposure to essential and non-essential trace elements and risks of congenital heart defects: A narrative review

Congenital heart defects (CHDs) are congenital abnormalities involving the gross structures of the heart and large blood vessels. Environmental factors, genetic factors and their interactions may contribute to the pathogenesis of CHDs. Generally, trace elements can be classified into essential trace elements and non-essential trace elements. Essential trace elements such as copper (Cu), zinc (Zn), iron (Fe), selenium (Se), and manganese (Mn) play important roles in human biological functions such as metabolic function, oxidative stress regulation, and embryonic development. Non-essential trace elements such as cadmium (Cd), arsenic (As), lead (Pb), nickle (Ni), barium (Ba), chromium (Cr) and mercury (Hg) are harmful to health even at low concentrations. Recent studies have revealed the potential involvement of these trace elements in the pathogenesis of CHDs. In this review, we summarized current studies exploring exposure to essential and non-essential trace elements and risks of CHDs, in order to provide further insights for the pathogenesis and prevention of CHDs.

Association of maternal and cord blood barium exposure with preschoolers' intellectual function: Evidence from the Ma'anshan Birth Cohort (MABC) study

OBJECTIVES

Barium is widely involved in drilling fluids, plastics, and personal care products. Although the neurodevelopmental toxicity of barium has been reported in animals, human data are scarce. This study aimed to investigate the effect of prenatal barium concentrations on preschoolers' intellectual function based on a birth cohort study.

METHODS

A total of 2164 mother-child pairs from Ma'anshan city, China were included in this study. We measured serum barium concentrations in the first, second, and third trimesters and in cord blood. Intellectual function in children aged 3.0-6.0 years old was assessed using the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition (WPPSI-IV). Linear regression models were used to analyze the association between averaged barium exposure during pregnancy and intellectual function. Multiple informant models were performed to jointly test for differences in associations between four repeated barium exposure and intellectual function. All models were further stratified by child sex.

RESULTS

Collectively, we observed significant inverse associations of average maternal barium exposure levels with verbal comprehension index (VCI), visual spatial index (VSI), processing speed index (PSI), and full-scale intelligence quotient (FSIQ) scores. Maternal serum log₁₀-transformed barium levels in the second trimester were inversely associated with VCI [-2.33 (95%CI: -4.02, -0.64)], VSI [-2.30 (95%CI: -4.08, -0.52)], working memory index (WMI) [-2.09 (95%CI: -3.71, -0.46)], PSI [-2.23 (95%CI: -3.82, -0.65)], and FSIQ scores [-2.73 (95%CI: -4.23, -1.22)]. Prenatal barium exposure was inversely associated with VCI, VSI, WMI, PSI, and FSIQ in girls, except for the fluid reasoning index (FRI). Additionally, inverse associations were found between prenatal barium exposure and VSI, PSI, and FSIQ in boys.

CONCLUSIONS

Prenatal barium exposure had detrimental effects on intellectual function in preschoolers and girls drove these inverse associations more than boys. The second trimester may be the critical window of neurotoxicity to barium exposure.

Novel trace elements detected in multiple stages of pregnancy impact neonatal birth weight by affecting gestational age

Prenatal exposure to elements may be associated with birth weight via shortening of gestation. This study aimed to determine if prenatal exposure is associated with birth weight, and to explore the potential mediating role of gestational age in the association. Within an established Bangladesh prospective birth cohort (2008-2011), we analyzed the concentrations of 15 elements in maternal serum samples collected during the first (n = 780) and second (n = 610) trimesters using inductively coupled plasma mass spectrometry. Mediation analyses explored the relationships between these elements, gestational age, and birth weight. Serum concentrations of cobalt (Co) (first trimester: b = 56.5; 95% confidence interval [CI]: 13.5-99.0; false discovery rate [FDR]-q = 0.035; second trimester: b = 73.3; 95% CI: 20.4-130.2; FDR-q = 0.037) and antimony (Sb) in both trimesters (first trimester:b = 92.1; 95% CI: 66.0-118.9; FDR-q < 0.001; second trimester: b = 93.3; 95% CI: 67.3-118.4; FDR-q < 0.001), and strontium (Sr) in the first trimester (b = 142.4; 95% CI: 41.6-247.9; FDR-q = 0.035) were positively associated with birth weight, while negative associations were observed for barium (Ba) (first trimester: b = -154.8; 95% CI: -217.9 to 91.8; FDR-q <0.001; second trimester: b = -26.7; 95% CI: -44.9 to 10.2; FDR-q < 0.001). These elements act partially by affecting gestation age and appear to have heightened impact among smaller infants. Further research is needed to determine the biological underpinnings of these effects, which may inform strategies to avert low birth weight.

Relationship between maternal exposure to heavy metal titanium and offspring congenital heart defects in Lanzhou, China: A nested case-control study

Background

Previous studies have found that exposure to heavy metals increased the incidence of congenital heart defects (CHDs). However, there is a paucity of information about the connection between exposure to titanium and CHDs. This study sought to examine the relationship between prenatal titanium exposure and the risk of CHDs in offspring.

Methods

We looked back on a birth cohort study that was carried out in our hospital between 2010 and 2012. The associations between titanium exposure and the risk of CHDs were analyzed by using logistic regression analysis to investigate titanium concentrations in maternal whole blood and fetal umbilical cord blood.

Results

A total of 97 case groups and 194 control groups were included for a nested case-control study. The [P₅₀ (P₂₅, P₇₅)] of titanium were 371.91 (188.85, 659.15) μg/L and 370.43 (264.86, 459.76) μg/L in serum titanium levels in pregnant women and in umbilical cord serum titanium content in the CHDs group, respectively. There was a moderate positive correlation between the concentration of titanium in pregnant women's blood and that in umbilical cord blood. A higher concentrations of maternal blood titanium level was associated with a greater risk of CHDs (OR 2.706, 95% CI 1.547–4.734), the multiple CHDs (OR 2.382, 95% CI 1.219–4.655), atrial septal defects (OR 2.367, 95% CI 1.215–4.609), and patent ductus arteriosus (OR 2.412, 95% CI 1.336–4.357). Dramatically higher concentrations of umbilical cord blood levels had an increased risk of CHDs and different heart defects.

Conclusion

Titanium can cross the placental barrier and the occurrence of CHDs may be related to titanium exposure.

Relationship between maternal heavy metal exposure and congenital heart defects: a systematic review and meta-analysis

Congenital heart defects (CHDs) are one of the major causes of death in infants and young children, and heavy metal exposure during pregnancy is one of the possible risk factors. However, the effect of heavy metal exposure on CHDs is still controversial. We searched English (PubMed, Web of Science) and Chinese (CNKI and WanFang database) databases for relevant articles. The summarized effect sizes and 95% confidence intervals (CIs) were calculated by pooling estimates using the random-effects model. Egger's test was used to estimate publication bias. Heterogeneity among studies was indicated by p-values and I². Finally, we conducted subgroup analyses to elucidate the causes of heterogeneity. Thirteen studies were included in this meta-analysis. A positive association between maternal exposure to heavy metals and CHDs was found. Pooling odds ratios (ORs) for arsenic, cadmium, mercury, and lead were 2.12, 1.30, 1.22, and 2.30, respectively for total CHDs. Regarding CHD subtypes, arsenic was associated with an increased risk of septal defects (OR: 1.82), barium with left ventricular outflow tract obstruction (LVOTO) (OR: 1.15) and septal defects (OR: 1.21), and lead with conotruncal defects (OR: 2.34) and LVOTO (OR: 1.93). A heterogeneous relationship was found between studies using different methods of measurement, which were mainly due to differences in actual exposure levels to heavy metals. This meta-analysis suggests significant associations between arsenic, cadmium, mercury, and lead exposure during pregnancy and an increased risk of specific CHDs in offspring. These findings underscore the importance of heavy metal exposure during pregnancy in the risk of CHDs in offspring.

Exposure to multiple toxic metals and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BACKGROUND

Early embryonic arrest is a great challenge for in vitro fertilization. Whether exposure to toxic metals is associated with an increased risk of early embryonic arrest warrants investigation.

OBJECTIVES

Here, we conducted a case-control study in infertile women to estimate the associations between blood barium (Ba), arsenic (As), mercury (Hg), and lead (Pb) exposure levels and the risk of early embryonic arrest.

METHODS

Ba, As, Hg, and Pb exposure levels in fasting blood collected from 74 infertile women (123 cycles) with early embryonic arrest and 157 infertile women (180 cycles) without early embryonic arrest were measured by ICP-MS. Bayesian kernel machine regression (BKMR) was used to assess the association of exposure level of toxic metals mixture with the risk of early embryonic arrest as well as to evaluate which metal playing a leading role in the association, and then generalized estimating equations (GEEs) were used to evaluate the relationship between the selected harmful metal and the risk of early embryonic arrest. Finally, the potential causes of early embryonic arrest originating from the harmful metal exposure were explored.

RESULTS

Blood Ba levels were significantly higher in the case group than that in the control group (p = 0.009) rather than As, Pb and Hg. Results from BKMR showed that exposure to toxic metals mixture increased the risk of early embryonic arrest, with Ba playing a leading role (PIP = 0.9612). GEE analysis showed that high Ba exposure level was related with the increased risk of early embryonic arrest (p < 0.05) and it impacted on the oogenesis significantly.

CONCLUSIONS

Our study found that exposure to toxic metals mixture was associated with the increased risk of early embryonic arrest, and Ba contributed most to the increased risk. Higher Ba exposure in whole blood corresponds to a higher risk of early embryonic arrest and impacted on the oogenesis significantly.

Association of both prenatal and early childhood multiple metals exposure with neurodevelopment in infant: A prospective cohort study

BACKGROUND

Impaired neurodevelopment of children has become a growing public concern; however, the associations between metals exposure and neurocognitive function have remained largely unknown.

OBJECTIVES

We systematically evaluated the associations of multiple metals exposure during pregnancy and childhood on the neurodevelopment of children aged 2-3 years.

METHODS

We measured 22 metals in the serum and urine among703 mother-child pairs from the Guangxi Birth Cohort Study. The neurocognitive development of children was assessed by the Gesell Development Diagnosis Scale (GDDS; Chinese version). Multiple linear regression models were used to evaluate the relationship between the metals (selected by elastic net regression) and the outcomes. The Bayesian kernel machine regression (BKMR) was used to evaluate the possible joint effect between the multiple metal mixture and the outcomes.

RESULTS

Prenatal aluminum (Al) exposure was negatively associated with the fine motor developmental quotient (DQ) (β = -1.545, 95%CI: 2.231, -0.859), adaption DQ (β = -1.182, 95%CI: 1.632, -0.732), language DQ (β = -1.284, 95% CI: 1.758, -0.809), and social DQ (β = -1.729, 95% CI: 2.406, -1.052) in the multi-metal model. Prenatal cadmium (Cd) exposure was negatively associated with gross motor DQ (β = -2.524, 95% CI: 4.060, -0.988), while postpartum Cd exposure was negatively associated with language DQ (β = -1.678, 95% CI: 3.227, -0.129). In stratified analyses, infants of different sexes had different sensitivities to metal exposure, and neurobehavioral development was more significantly affected by metal exposure in the first and second trimester. BKMR analysis revealed a negative joint effect of the Al, Cd, and selenium (Se) on the language DQ score; postpartum Cd exposure played a major role in this relationship.

CONCLUSION

Prenatal exposure to Al, Ba, Cd, molybdenum (Mo), lead (Pb), antimony (Sb), and strontium (Sr), and postpartum exposure to cobalt (Co), Cd, stannum (Sn), iron (Fe), nickel (Ni), and Se are associated with neurological development of infants. The first and second trimester might be the most sensitive period when metal exposure affects neurodevelopment.

Environmental barium: potential exposure and health-hazards

The relatively widespread presence of environmental barium is raising a growing public awareness as it can lead to different health conditions. Its presence in humans may produce several effects, especially among those chronically exposed from low to moderate doses. Barium accumulation can mainly occur by exposure in the workplace or from drinking contaminated water. However, this element is also assumed with the diet, mainly from plant foods. The average amount of barium intake worldwide and its geographical variation is little known due to the lack of research attention. Barium was never considered as an essential nutrient for humans, although it is undoubtedly naturally abundant enough and distinctive in its chemical properties that it might well have some biochemical function, e.g., for regulatory purposes, both in animals and plants. The information on the potential health effects of barium exposure is primarily based on animal studies and reported as comprising kidney diseases, neurological, cardiovascular, mental, and metabolic disorders. The present paper considers exposure and potential health concerns on environmental barium, giving evidence to information that can be used in future epidemiological and experimental studies.

Prenatal exposure to barium and the occurrence of neural tube defects in offspring

Neural tube defects (NTDs) have a complex etiology. Few studies have assessed alkaline earth metals exposures and occurrence of NTDs. We examined the association between prenatal exposure to magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba) and risk for NTDs in a case-control study, and assessed the teratogenic effects of Ba on mice. Placentas were collected from 408 women with NTD-affected pregnancies and 593 women who delivered healthy infants, and concentrations of these metals were determined as prenatal exposure markers. The single effect of individual exposure and joint effect of coexposure to these metals were evaluated with logistic regression and Bayesian kernel machine regression (BKMR), respectively. Barium chloride (BaCl₂) was intragastrically administered to pregnant ICR mice and fetal mice were examined for NTDs. Median concentrations of Mg and Ba were higher in NTD cases than in controls (P_all < 0.001). In logistic regression, higher levels of Ba were associated with 1.6-fold increased risk for NTDs (95% confidence interval: 1.06-2.43). In BKMR, the joint effect of the four-metal mixture on NTD risk increased steadily with the levels of the mixture. A change in Ba concentration from the 25^th to 75^th percentile displayed a risk effect when the other three metals were fixed at the 25^th, 50^th or 75^th percentile, while such a change in Ca concentration showed a protective effect when the other metals were held at the 25^th or 50^th percentile. No interactions among metals were found. In the mouse experiment, dams treated with 200 mg/kg BaCl₂ showed 16.8% of NTDs in fetal mice, compared to 2.6% in the untreated control group (P < 0.01). Taken together, higher mixture levels of the four alkaline earth metals were associated with increased risk for NTDs, with Ba being the major contributor for the joint effect. Intragastric administration of Ba can induce NTDs in mice.

Evaluation of Fetal Exposures to Metals and Metalloids through Meconium Analyses: A Review

This paper surveys the existing scientific literature on metals concentrations in meconium. We examine some 32 papers that analyzed meconium for aluminum, arsenic, barium, calcium, chromium, copper, iron, lithium, magnesium, manganese, zinc, lead, mercury, manganese, molybdenum, nickel, phosphorus, lead, antimony, selenium, tin, vanadium, and zinc. Because of the lack of detail in the statistics it is not possible to do a rigorous meta-analysis. What stands out is that almost every study had subjects with seemingly large amounts of at least one of the metals. The significance of metals in meconium is not clear beyond an indication of exposure although some studies have correlated metals in meconium to a number of adverse outcomes. A number of outstanding questions have been identified that, if resolved, would greatly increase the utility of meconium analysis for assessment of long-term gestational metals exposures. Among these are questions of the developmental and long-term significance of metals detected in meconium, the kinetics and interactions among metals in maternal and fetal compartments and questions on best methods for meconium analyses.

Association between selected alkaline earth elements concentrations in umbilical cord and risk for cleft lip with or without cleft palate

The relationship between alkaline earth elements in utero exposure and the risk of cleft lip with or without cleft palate (CL ± P) remains unclear. We aimed to investigate the associations between the concentration of alkaline earth elements in umbilical cord and risk for CL ± P. A case-control study was carried out in this study, including 78 cases and 142 controls. Association between each metals and the risk of CL ± P were evaluated with conventional logistic regression, bayesian kernel machine regression and weighted quantile sum regression models. Logistic regression model indicated that in utero exposure to higher levels of Barium was associated with increasing risk for CL ± P (odds ratio = 2.79, 95% confidence interval, 1.22-6.38) and for cleft lip with cleft palate (odds ratio = 3.94, 95% confidence interval, 1.45-10.72). Bayesian kernel machine regression model showed the statistical association between the metals mixture and risk difference of CL ± P, and barium was associated with CL ± P risk when all other metals were held fixed at the 25th percentiles (risk difference = 1.07, 95% confidence interval, 1.01-1.14). In weighted quantile sum model, barium accounted for most of the weight index in the combined effect of the metals mixture. The weighted quantile sum index showed that a quartile increase in the index resulted in an increase odds of 1.69 (95% confidence interval, 1.16-2.46) for CL ± P and of 2.11 (95% confidence interval, 1.34-3.35) for CLP. No associations were found in the three statistical models between Calcium, Magnesium and Strontium and the risks of CL ± P. In conclusion, in utero exposure to mixtures of alkaline earth elements was associated with an increased risk for CL ± P, of which barium was likely to be important factors in the development.

Prenatal toxic metal mixture exposure and newborn telomere length: Modification by maternal antioxidant intake

BACKGROUND

Telomere length (TL) predicts the onset of cellular senescence and correlates with longevity and age-related disease risk. While telomeres erode throughout life, adults display fixed ranking and tracking of TL, supporting the importance of the early environment in determining inter-individual variability across the life course. Given their guanine-rich structure, telomeres are highly susceptible to oxidative stress (OS). We examined maternal metal exposure, which can induce OS, in relation to newborn TL. We also considered the modifying role of maternal antioxidant intake.

METHODS

Analyses included 100 mother-newborn pairs enrolled in the Boston and New York City-based PRogramming of Intergenerational Stress Mechanisms (PRISM) pregnancy cohort. We measured As, Ba, Cd, Ni, and Pb in maternal late-pregnancy urine by ICP-MS and quantified relative leukocyte TL (rLTL) in cord blood using qPCR. We used Weighted Quantile Sum (WQS) regression to estimate the metal mixture - rLTL association and conducted repeated holdout validation to improve the stability of estimates across data partitions. We examined models stratified by high (>median) versus low (≤median) maternal antioxidant intake, estimated from Block98 Food Frequency Questionnaires. We considered urinary creatinine, week of urine collection, maternal age, and race/ethnicity as covariates.

RESULTS

In adjusted models, urinary metals were inversely associated with newborn rLTL (βWQS = -0.50, 95% CI: -0.78, -0.21). The top metals contributing to the negative association included Ba (weight: 35.4%), Cd (24.5%) and Pb (26.9%). In models stratified by antioxidant intake, the significant inverse association between metals and rLTL remained only among mothers with low antioxidant intake (low: βWQS = -0.92, 95% CI: -1.53, -0.30; high: βWQS = -0.03, 95% CI: -0.58, 0.52). Results were similar in unadjusted models.

CONCLUSIONS

Relative LTL was shorter among newborns of mothers with higher exposure to metals during pregnancy. Higher maternal antioxidant intake may mitigate the negative influence of metals on newborn rLTL.

Barium isotopic fractionation during strong weathering of basalt in a tropical climate

Barium (Ba) is an element which is toxic to humans, plants, and animals. Deciphering the geochemical behavior of Ba in soils is fundamental for assessing the potentials risks posed by Ba. Ba isotopes are a potentially robust tracer of Ba in soils. In this study, the controlling factors of Ba isotopic fractionation in a latosol profile were investigated through sequential-extraction experiments. Furthermore, dissolution experiments were conducted to understand Ba isotopic fractionation during the dissolution of basalts. The sequential-extraction experiments revealed δ^137/134Ba ratios in various fractions that were remarkably heterogeneous: -0.28‰ to -0.15‰ in the exchangeable fraction; -0.32‰ to -0.16‰ in reducible Fe-Mn (oxyhydr)oxides; and 0.06‰ to 0.46‰ in residues. This indicates that light Ba isotopes are preferentially adsorbed on secondary minerals and associated with Fe-Mn (oxyhydr)oxides. Both processes play important roles in storing Ba originally released from minerals. Results of the sequential-extraction and dissolution experiments revealed that light Ba isotopes favored fluids during the dissolution of silicate minerals, while heavy Ba isotopes were prone to being released from interlayers of micaceous layers. Collectively, the dissolution of minerals, adsorption on secondary minerals, and formation of easily reducible Fe-Mn (oxyhydr)oxides govern Ba isotope fractionation and Ba transport in soils.

Association between metal cobalt exposure and the risk of congenital heart defect occurrence in offspring: a multi-hospital case-control study

Background

Many studies have investigated heavy metal exposure could increase the occurrence of congenital heart defects (CHDs). However, there are limited data regarding the relationship between cobalt exposure and CHD occurrence in offspring. The aim of this study was to analyze the association between cobalt exposure in mothers and the risk of CHDs in offspring.

Materials and methods

In order to explore the association between cobalt exposure and occurrence of congenital heart defect (CHD), a case-control study with 490 controls and 399 cases with CHDs in China were developed. The concentrations of cobalt in hair of pregnant woman and fetal placental tissue were measured and processed by a logistic regression analysis to explore the relationship between cobalt exposure and risk of CHDs.

Results

The median concentration of hair cobalt in the control and case group was 0.023 ng/mg and 0.033 ng/mg (aOR, 1.837; 95% CI, 1.468–2.299; P < 0.001), respectively. And the median (5–95% range) fetal placental cobalt concentrations were 19.350 ng/g and 42.500 ng/g (aOR, 2.924; 95% CI, 2.211–3.868; P < 0.001) in the control and case groups, respectively. Significant differences in the middle level of cobalt in hair were found in the different CHD subtypes, including septal defects, conotruncal defects, right ventricular outflow tract obstruction, and left ventricular outflow tract obstruction (P < 0.001). Dramatically, different cobalt concentrations in fetal placental tissue were found in all subtypes of cases with CHDs (P < 0.01).

Conclusions

The finding suggested that the occurrence of CHDs may be associated with cobalt exposure.

Biomonitoring of Metals in Children Living in an Urban Area and Close to Waste Incinerators

The impact of waste incinerators is usually examined by measuring environmental pollutants. Biomonitoring has been limited, until now, to few metals and to adults. We explored accumulation of a comprehensive panel of metals in children free-living in an urban area hosting two waste incinerators. Children were divided by georeferentiation in exposed and control groups, and toenail concentrations of 23 metals were thereafter assessed. The percentage of children having toenail metal concentrations above the limit of detection was higher in exposed children than in controls for Al, Ba, Mn, Cu, and V. Exposed children had higher absolute concentrations of Ba, Mn, Cu, and V, as compared with those living in the reference area. The Tobit regression identified living in the exposed area as a significant predictor of Ba, Ni, Cu, Mn, and V concentrations, after adjusting for covariates. The concentrations of Ba, Mn, Ni, and Cu correlated with each other, suggesting a possible common source of emission. Exposure to emissions derived from waste incinerators in an urban setting can lead to body accumulation of specific metals in children. Toenail metal concentration should be considered a noninvasive and adequate biomonitoring tool and an early warning indicator which should integrate the environmental monitoring of pollutants.

Effects of Cr(VI) exposure on electrocardiogram, myocardial enzyme parameters, inflammatory factors, oxidative kinase, and ATPase of the heart in Chinese rural dogs

Heavily chromium-polluted areas, where people are prohibited from entering, are paradises for stray dogs. In this study, stray dogs were used to study the effects of chromium exposure on the heart of dogs in severely Cr(VI)-contaminated rural areas of China. The dogs were given water (control), low dose (L, 0.92 mg/kg), medium dose (M, 1.15 mg/kg), and high dose (H, 1.38 mg/kg) of Cr(VI). The changes of electrocardiogram (ECG), myocardial enzyme parameters, inflammatory factors, oxidative kinase, and ATPase were measured to determine the toxicity of chromium on the heart of dogs. Results showed that the ST segment of ECG increased significantly, and the amplitude of T wave increased in the experimental group. The myocardial enzyme (CK-MB, AST, CK, and LDH) content in groups M and H increased significantly over time. The values of CAT, T-SOD, IL-10, and ATPase (K+-Na+-ATPase and Ca2+-Mg2+-ATPase) decreased with the increase of Cr(VI) dose, and the content of MDA, IL-1β, IL-8, and TNF-α increased with the increase of Cr(VI) dose. Our study suggested that the heart of Chinese rural dog was damaged by Cr(VI), and Cr(VI) could cause oxidative damage and alteration of ATPase content in dogs.

Environmental Contaminants and Congenital Heart Defects: A Re-Evaluation of the Evidence

Congenital heart defects (CHDs) are a common birth defect of largely unknown etiology, with high fetal and neonatal mortality. A review of CHDs and environmental contaminant exposure found that meta-analyses showed only modest associations for smoking, vehicle exhaust components, disinfectant by-products and proximity to incinerators, with stronger results from the newer, larger and better quality studies masked by the typical absence of effect in older studies. Recent studies of exposure to agricultural pesticides, solvents, metals and landfill sites also showed associations. Certain contaminants have been associated with certain CHDs, with septal defects being the most common. Frequent methodological problems include failure to account for potential confounders or maternal/paternal preconception exposure, differences in diagnosing, defining and classifying CHDs, grouping of defects to increase power, grouping of contaminants with dissimilar mechanisms, exclusion of pregnancies that result in death or later life diagnosis, and the assumption that maternal residence at birth is the same as at conception. Furthermore, most studies use measurement estimates of one exposure, ignoring the many additional contaminant exposures in daily life. All these problems can distort and underestimate the true associations. Impaired methylation is a common mechanism, suggesting that supplementary folate may be protective for any birth defect.