Preliminary analysis of in utero low-level arsenic exposure and fetal growth using biometric measurements extracted from fetal ultrasound reports

Associations of intrauterine exposure to manganese with fetal and early-childhood growth: a prospective prenatal cohort study

Prenatal manganese (Mn) exposure may be related to poor birth outcomes; however, there are few relevant epidemiological reports on the effects of intrauterine Mn levels on intrauterine fetal and early childhood growth. From 2013 to 2016, 2082 pairs of mothers and infants were recruited in Wuhan, China, who provided an entire set of urine samples during their first, second, and third trimesters. Fetal head circumference (HC), abdominal circumference (AC), femoral length (FL), and estimated fetal weight (EFW) were obtained by ultrasound at the 16, 24, and 31 weeks of pregnancy. When the children were born, 6 months old, 12 months old, and 24 months old, their weight, height, weight-for-height, and BMI were measured. We used generalized linear models, generalized estimated equations, and restricted cubic spline curves (RCS) to investigate the linear and nonlinear relationships between antenatal Mn levels and fetal and early childhood growth. In all fetuses, Mn exposure during the 1st and 2nd gestation was associated with decreased fetal AC, FL, and EFW at 24 weeks (e.g., for each doubling of urinary Mn concentrations during the 1st and 2nd gestation, the SD score of EFW at 24 weeks decreased by - 4.16% (95% CI, - 6.22%, - 2.10%) and - 3.78% (95% CI, - 5.86%, - 1.70%)). Mn concentrations in the highest tertile group of the 1st and 2nd gestation were related to decreased fetus growth parameters compared to the lowest tertile group. For each doubling of the average Mn concentrations during pregnancy, the z-scores of weight, weight-for-height, and BMI at 12 months decreased, with percentage changes of - 2.93% (95% CI, - 5.08%, - 0.79%), - 3.25% (95% CI, - 5.56%, - 0.94%), and - 3.09% (95% CI, - 5.44%, - 0.73%). In the RCS model, we found a reverse U-shaped association between 1st trimester Mn concentration and fetal FL at 16 weeks and HC at 31 weeks in male fetuses and a non-linear association between mean Mn concentration during pregnancy and girls' weight-for-height and BMI at 6 months. Intrauterine exposure to Mn may be related to restricted growth in the fetus and early childhood, especially in fetuses at 24 weeks of gestation and children at 12 months of age. Also, meaningful curvilinear relationships were found in the sex stratification.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

Maternal Exposure to Arsenic and Its Impact on Maternal and Fetal Health: A Review

Arsenic exposure is a significant public health issue, with harmful effects caused by its use in commercial products such as car batteries, pesticides, and herbicides. Arsenic has three main compounds: inorganic, organic, and arsine gas. Inorganic arsenic compounds in water are highly toxic. The daily intake of arsenic from food and beverages is between 20 and 300 mcg/day. Arsenic is known for its carcinogenic properties and is classified as a human carcinogen by different institutions. Exposure can lead to oxidative stress, DNA damage, and epigenetic deregulation, which can cause endocrine disorders, altered signal transduction pathways, and cell proliferation. In addition, arsenic can easily cross the placenta, making it a critical concern for maternal and fetal health. Exposure can lead to complications such as gestational diabetes, anemia, low birth weight, miscarriage, and congenital anomalies. Female babies are particularly vulnerable to the negative impact of arsenic exposure, with a higher risk of low weight for gestational age and congenital cardiac anomalies. Therefore, it is crucial to monitor and regulate the levels of arsenic in drinking water and food sources to prevent these adverse health outcomes. Further research is necessary to fully understand the impact of arsenic exposure on human health, especially during pregnancy and infancy, by implementing preventative measures and monitoring the levels of arsenic in the environment.

Prenatal arsenic exposure induces immunometabolic alteration and renal injury in rats

Arsenic (As) exposure is progressively associated with chronic kidney disease (CKD), a leading public health concern present worldwide. The adverse effect of As exposure on the kidneys of people living in As endemic areas have not been extensively studied. Furthermore, the impact of only prenatal exposure to As on the progression of CKD also has not been fully characterized. In the present study, we examined the effect of prenatal exposure to low doses of As 0.04 and 0.4 mg/kg body weight (0.04 and 0.4 ppm, respectively) on the progression of CKD in male offspring using a Wistar rat model. Interestingly, only prenatal As exposure was sufficient to elevate the expression of profibrotic (TGF-β1) and proinflammatory (IL-1α, MIP-2α, RANTES, and TNF-α) cytokines at 2-day, 12- and 38-week time points in the exposed progeny. Further, alteration in adipogenic factors (ghrelin, leptin, and glucagon) was also observed in 12- and 38-week old male offspring prenatally exposed to As. An altered level of these factors coincides with impaired glucose metabolism and homeostasis accompanied by progressive kidney damage. We observed a significant increase in the deposition of extracellular matrix components and glomerular and tubular damage in the kidneys of 38-week-old male offspring prenatally exposed to As. Furthermore, the overexpression of TGF-β1 in kidneys corresponds with hypermethylation of the TGF-β1 gene-body, indicating a possible involvement of prenatal As exposure-driven epigenetic modulations of TGF-β1 expression. Our study provides evidence that prenatal As exposure to males can adversely affect the immunometabolism of offspring which can promote kidney damage later in life.

Prenatal exposure to heavy metal mixtures and anthropometric birth outcomes: a cross-sectional study

BACKGROUND

Numerous studies have suggested significant associations between prenatal exposure to heavy metals and newborn anthropometric measures. However, little is known about the effect of various heavy metal mixtures at relatively low concentrations. Hence, this study aimed to investigate associations between prenatal exposures to a wide range of individual heavy metals and heavy metal mixtures with anthropometric measures of newborns.

METHODS

We recruited 975 mother-term infant pairs from two major hospitals in Israel. Associations between eight heavy metals (arsenic, cadmium, chromium, mercury, nickel, lead, selenium, and thallium) detected in maternal urine samples on the day of delivery with weight, length, and head circumference at birth were estimated using linear and Bayesian kernel machine regression (BKMR) models.

RESULTS

Most heavy metals examined in our study were observed in lower concentrations than in other studies, except for selenium. In the linear as well as the BKMR models, birth weight and length were negatively associated with levels of chromium. Birth weight was found to be negatively associated with thallium and positively associated with nickel.

CONCLUSION

By using a large sample size and advanced statistical models, we could examine the association between prenatal exposure to metals in relatively low concentrations and anthropometric measures of newborns. Chromium was suggested to be the most influential metal in the mixture, and its associations with birth weight and length were found negative. Head circumference was neither associated with any of the metals, yet the levels of metals detected in our sample were relatively low. The suggested associations should be further investigated and could shed light on complex biochemical processes involved in intrauterine fetal development.

Prenatal metal mixture exposure and birth weight: A two-stage analysis in two prospective cohort studies

The understanding of the impact of prenatal exposure to metal mixtures on birth weight is limited. We aimed to identify metal mixture components associated with birth weight and to determine additional pairwise interactions between metals showing such associations. Concentrations of 18 metals were measured using inductively coupled plasma mass spectrometry in urine samples collected in the 3rd trimester from a prenatal cohort (discovery; n = 1849) and the Healthy Baby Cohort (replication; n = 7255) in Wuhan, China. In the discovery set, we used two penalized regression models, i.e., elastic net regression for main effects and a lasso for hierarchical interactions, to identify important mixture components associated with birth weight, which were then replicated. We observed that 8 of the 18 measured metals were retained by elastic net regression, with five metals (vanadium, manganese, iron, cesium, and barium) showing negative associations with Z-scores for birth weight and three metals (cobalt, zinc, and strontium) showing positive associations. In replication set, associations remained significant for vanadium (β = -0.035; 95% confidence interval [CI], -0.059 to -0.010), cobalt (β = 0.073; 95% CI, 0.049 to 0.097), and zinc (β = 0.040; 95% CI, 0.016 to 0.065) after Bonferroni correction. We additionally identified and replicated a single pairwise interaction between iron and copper exposure on birth weight (P < 0.001). Using a two-stage analysis, we identified and replicated individual metals and additional pairwise interactions-associated birth weight. The approach could be used in other studies estimating the effect of complex mixtures on human health.

Prenatal metal mixture concentrations and reward motivation in children

Reward motivation is a complex umbrella term encompassing the cognitions, emotions, and behaviors involved in the activation, execution, and persistence of goal-directed behavior. Altered reward motivation in children is characteristic of many neurodevelopmental and psychiatric disorders. Previously difficult to operationalize, the Progressive Ratio (PR) task has been widely used to assess reward motivation in animal and human studies, including children. Because the neural circuitry supporting reward motivation starts developing during pregnancy, and is sensitive to disruption by environmental toxicants, including metals, the goal of this study was to examine the association between prenatal concentrations of a mixture of neurotoxic metals and reward motivation in children. We measured reward motivation by administering a PR test to 373 children ages 6-8 years enrolled in the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) Study in Mexico City. Children were asked to press a response lever for a token reward; one press on the response lever was required to earn the first token and each subsequent token required an additional 10 lever presses. Maternal blood concentrations of lead, manganese, zinc, arsenic, cadmium, and selenium were measured using inductively-coupled plasma mass spectrometry during the 2nd and 3rd trimesters of pregnancy. We performed generalized Weighted Quantile Sum (gWQS) regression analyses to examine associations between the prenatal metal mixture and reward motivation; adjusting for child sex, birthweight and age; and maternal IQ, education, and socioeconomic status. The prenatal metal mixture was significantly associated with higher motivation as indicated by more lever presses (ß = 0.02, p < 0.001) and a shorter time between receiving the reinforcer and the first press (ß = 0.23, p = 0.01), and between subsequent presses (ß = 0.07, p = 0.005). Contributions of different metals to this association differed by trimester and child sex. These findings suggest that children with increased exposure to metal during the 2nd and 3rd trimesters of gestation demonstrate increased reward motivation, which may reflect a tendency to perseverate or hypersensitivity to positive reinforcement.

Additive and Interactive Associations of Environmental and Sociodemographic Factors with the Genotypes of Three Glutathione S-Transferase Genes in Relation to the Blood Arsenic Concentrations of Children in Jamaica

Arsenic (As) is a metalloid that has been classified as a xenobiotic with toxic effects on human beings, especially on children. Since the soil in Jamaica contains As, dietary intake is considered the main source of As exposure in Jamaicans. In addition, glutathione S-transferase (GST) genes, including GSTT1, GSTP1, and GSTM1, play an important role in the metabolism of xenobiotics including As in humans. Using data from 375 typically developing children (2–8 years) in Jamaica, we investigated the environmental and sociodemographic factors, as well as their possible interactions with the children’s genotype for GST genes in relation to having a detectable level of blood As concentration (i.e., >1.3 μg/L). Using multivariable logistic regression, we have identified environmental factors significantly associated with blood As concentrations that include a child’s age, parental education levels, and the consumption of saltwater fish, cabbage, broad beans, and avocado (all p < 0.01). Based on the multivariable analysis including gene x environment interactions, we found that among children with the Ile/Ile genotype for GSTP1 Ile105Val, children who consumed avocado had higher odds of having a detectable blood As concentration compared to children who did not eat avocado.

Prenatal arsenic exposure interferes in postnatal immunocompetence despite an absence of ongoing arsenic exposure

Arsenic (As) readily crosses the placenta and exposure of the fetus may cause adverse consequences later in life, including immunomodulation. In the current study, the question was asked how the immune repertoire might respond in postnatal life when there is no further As exposure. Here, pregnant mice (Balb/c [H-2^d]) were exposed to arsenic trioxide (As₂O₃) through their drinking water from time of conception until parturition. Their offspring, 4-week-old mice who had not been exposed again to As, were used for functional analyses of innate, humoral and cellular immunity. Compared to cells from non-As-exposed dam offspring, isolated peritoneal macro-phages (Mϕ) displayed no differences in T-cell stimulating ability. Levels of circulating IgG_2a but not IgG₁ were decreased in As-exposed dam offspring as compared to control offspring counterparts. Mixed-leukocyte reactions (MLR) indicated that CD4⁺ T-cells from the prenatal As-exposed mice were significantly less responsive to allogenic stimulation as evidenced by decreases in interferon (IFN)-γ and IL-2 production and in expression of CD44 and CD69 (but not CD25) activation markers. Interestingly, the Mϕ from the prenatal As-exposed mice were capable of stimulating normal allogenic T-cells, indicating that T-cells from these mice were refractory to allogenic signals. There was also a significant decrease in absolute numbers of splenic CD4⁺ and CD8⁺ T-cells due to prenatal As exposure (as compared to control). Lastly, the impaired immune function of the prenatal As-exposed mice was correlated with a very strong susceptibility to Escherichia coli infection. Taken together, the data from this study clearly show that in utero As exposure may continue to perpetuate a dampening effect on the immune repertoire of offspring, even into the early stages of postnatal life.

Prenatal metal mixtures and fetal size in mid-pregnancy in the MADRES study

BACKGROUND

Fetal growth is predictive of health later in life. Both toxic and essential metals influence fetal growth, but most studies have focused on these elements individually and used birth weight as an indicator of fetal growth. The objective of the current study was to investigate the impact of a mixture of metals on fetal size in mid-pregnancy in a predominately lower income Hispanic pregnancy cohort in Los Angeles.

METHODS

For our primary analysis, we focused on six elements that have previously been associated individually with fetal size, including arsenic (As), barium (Ba), cadmium (Cd), mercury (Hg), molybdenum (Mo), and tin (Sn), measured in maternal urine samples collected in early pregnancy (median: 12.4 weeks gestation). In an exploratory analysis, we additionally included cobalt (Co), nickel (Ni), antimony (Sb), and thallium (Tl). Using covariate-adjusted Bayesian Kernel Machine Regression (BKMR) as our main mixture modeling approach, we examined the impact of these metals on fetal biometry measures obtained between 18 and 22 weeks gestation, with a focus on estimated fetal weight (EFW).

RESULTS

BKMR identified Mo and Ba as the mixture components that contributed most to associations with EFW. Linear associations were observed for both metals. An increase in Mo from the 25th to 75th percentile was associated with a 0.114 (95% credible interval (CI): 0.019, 0.247) SD higher EFW, equivalent to a 7.4 g difference. Similar associations were observed between Mo and the other fetal measures evaluated. In contrast, an increase in Ba from the 25th to 75th percentile was associated with a -0.076 (95% CI: 0.217, 0.066) SD lower EFW, equivalent to a 4.9 g difference. Similar inverse associations were observed for Ba in relation to abdominal circumference and biparietal diameter. BKMR also identified a possible interaction between Ba and Mo in relation to head circumference, suggesting that the positive associations between Mo and this outcome may be attenuated at high levels of Ba, which was consistent with findings from linear regression (P_interaction = 0.03). In an exploratory analysis accounting for a larger mixture of metals, Mo and Ba consistently contributed most to associations with EFW. An inverse association was also identified between Sb and EFW.

CONCLUSIONS

Our results suggest that Mo may promote fetal growth, while Ba and Sb may reduce fetal growth, in this population.

Characterization of urinary concentrations of heavy metals among socioeconomically disadvantaged black pregnant women

The objective of this study was to characterize exposures to metals using biological samples collected on socioeconomically disadvantaged black pregnant women. We obtained 131 anonymous urine samples provided by black pregnant women visiting a Medicaid-serving prenatal clinic in Houston, TX, from March 27, 2017 to April 11, 2017. We analyzed urine samples for 15 metals including cadmium (Cd), arsenic (As), lead (Pb), and nickel (Ni) and for creatinine and cotinine. We found that median concentrations of zinc (Zn), selenium (Se), and aluminum (Al) among black pregnant women in this study were 1.5 to 3 times higher than levels reported among a cohort of well-educated non-Hispanic white pregnancy planners. We also observed elevated levels of urinary Cd and antimony (Sb) as compared with those reported for a nationally representative sample of adult women in the USA. Based on the results of an exploratory factor analysis, potential sources of metal exposures in this population may arise in home environments or be due to diet, industrial and natural sources, or traffic.

Combining Nonclinical Determinants of Health and Clinical Data for Research and Evaluation: Rapid Review

Background

Nonclinical determinants of health are of increasing importance to health care delivery and health policy. Concurrent with growing interest in better addressing patients’ nonmedical issues is the exponential growth in availability of data sources that provide insight into these nonclinical determinants of health.

Objective

This review aimed to characterize the state of the existing literature on the use of nonclinical health indicators in conjunction with clinical data sources.

Methods

We conducted a rapid review of articles and relevant agency publications published in English. Eligible studies described the effect of, the methods for, or the need for combining nonclinical data with clinical data and were published in the United States between January 2010 and April 2018. Additional reports were obtained by manual searching. Records were screened for inclusion in 2 rounds by 4 trained reviewers with interrater reliability checks. From each article, we abstracted the measures, data sources, and level of measurement (individual or aggregate) for each nonclinical determinant of health reported.

Results

A total of 178 articles were included in the review. The articles collectively reported on 744 different nonclinical determinants of health measures. Measures related to socioeconomic status and material conditions were most prevalent (included in 90% of articles), followed by the closely related domain of social circumstances (included in 25% of articles), reflecting the widespread availability and use of standard demographic measures such as household income, marital status, education, race, and ethnicity in public health surveillance. Measures related to health-related behaviors (eg, smoking, diet, tobacco, and substance abuse), the built environment (eg, transportation, sidewalks, and buildings), natural environment (eg, air quality and pollution), and health services and conditions (eg, provider of care supply, utilization, and disease prevalence) were less common, whereas measures related to public policies were rare. When combining nonclinical and clinical data, a majority of studies associated aggregate, area-level nonclinical measures with individual-level clinical data by matching geographical location.

Conclusions

A variety of nonclinical determinants of health measures have been widely but unevenly used in conjunction with clinical data to support population health research.

Prenatal exposure to metal mixture and sex-specific birth outcomes in the New Hampshire Birth Cohort Study

BACKGROUND

In utero exposure to individual metals may impact fetal growth, though little is known about the effects of exposure to metal mixtures. Therefore, we investigated joint effects of in utero exposure to a mixture of As (arsenic), Mn (manganese), and Pb (lead) on newborn outcomes in a United States population.

METHODS

Concentrations of As, Mn, and Pb were determined in maternal postpartum toenail samples, a biomarker of in utero exposure, from 989 maternal-infant pairs (492 females and 497 males). Newborns' anthropometric characteristics, including head circumference, length, and weight, were obtained from medical records. The joint effects of the three metals were modeled using Bayesian kernel machine regression and linear regression. Both sex-combined and sex-stratified statistical analyses were performed.

RESULTS

We observed an inverted-U-shape association between maternal toenail Mn concentrations and newborn head circumference, particularly among female infants. Concentrations of Pb were related to reduced head circumference, weight, and length, especially among females at lower concentrations of the other metals. Overall, toenail As concentrations were related to reduced head circumference, especially among males, and an increase in birth length and weight among females. We found little evidence of As interactions with other metals within the mixture.

CONCLUSIONS

Our findings suggest that in utero metal mixture exposures may influence birth outcomes, and that such relations may differ by infant sex.

Association of maternal arsenic exposure with birth size: A systematic review and meta-analysis

OBJECTIVES

Chronic exposure to arsenic during pregnancy or early life continues to be a major global health problem worldwide, affecting hundreds of millions of people. However, its effects on birth size are uncertain. The aim of this study is to summarized the association between maternal arsenic exposure and birth size.

METHODS

A comprehensive literature search was conducted on the maternal arsenic exposure and birth size (birth weight, birth length, head circumference and chest circumference) through databases (PubMed, Qvid Medline, Web of Science, Cochrane and EMBASE), the last search was in March 2019. Heterogeneity was testes by using the Q statistic and stratifying for epidemiological factors. The possibility of publication bias was assessed through Begg's test.

RESULTS

A total of 12 studies provided sufficient data were included. Meta-analysis revealed that maternal arsenic exposure was associated with the decrease of birth weight (β = -25.0 g; 95% CI: -41.0, -9.0) and head circumference (β = -0.12 cm; 95% CI: -0.24, -0.01) in random-effect model, birth length (β = -0.12 cm; 95% CI: -0.17, -0.07) in fixed-effect model, no significant reduction was suggested in chest circumference (β = -0.74 cm; 95% CI: -1.78, 0.3). In addition, we found that the birth weight decreased stronger in women living in the Americas, or appling the exposure marker of urine.

CONCLUSIONS

Maternal arsenic exposure is associated with the decrease of the birth weight, length and head circumference. Millions of people are still exposured to high-level arsenic, therefore, high quality epidemiologic studies that involve large samples are necessary to determine the precise relationships between maternal arsenic exposure with birth size. And that effective mitigation measures are also need to prevent arsenic exposure in women of reproductive age.

Is prenatal arsenic exposure associated with salivary cortisol in infants in Arica, Chile? An exploratory cohort study

INTRODUCTION

In animal models, gestational exposure to inorganic arsenic has been associated with higher corticosterone concentration and consequent impairment of stress control in offspring. An equivalent association relating cortisol, a glucocorticoid hormone, in humans has not been previously studied.

OBJECTIVE

The aim of the study was to explore the association between prenatal inorganic arsenic exposure and salivary cortisol in infants from Arica, Chile.

MATERIAL AND METHODS

A cohort study of 168 mother-child dyads was recruited. In the 2nd trimester of pregnancy, urinary inorganic arsenic was assessed; 18-24 months after delivery, salivary cortisol was measured in the children. Maternal cortisol, maternal depression, stress, and socio-economic status were also evaluated.

RESULTS

The adjusted association was estimated with multiple linear regression after evaluating confounding through a directed acyclic graph. Median urinary inorganic arsenic in pregnant women was 14.1 µg/L (IQR: 10.4-21.7) while salivary cortisol in the children was 0.17 µg/L (IQR: 0.11-0.38). Among children from the highest income families (> 614 USD/month), arsenic exposure was associated with salivary cortisol. Children in the third quartile of arsenic exposure had -0.769 units of the logarithm of salivary cortiso, compared with those in the first quartile (p = 0.045).

CONCLUSIONS

In this sample, prenatal exposure to arsenic was associated with salivary cortisol (third quartile of inorganic arsenic), only in infants belonging the highest income strata (> 614 USD). More studies are needed to confirm these preliminary results.

Long-Term Health Effects and Underlying Biological Mechanisms of Developmental Exposure to Arsenic

PURPOSE OF REVIEW

Exposure to inorganic arsenic (iAs) via drinking water represents a significant global public health threat with chronic exposure associated with cancer, skin lesions, neurological impairment, and cardiovascular diseases. Particularly susceptible populations include the developing fetus and young children. This review summarizes some of the critical studies of the long-term health effects and underlying biological mechanisms related to developmental exposure to arsenic. It also highlights the complex factors, such as the sex of the exposed individual, that contribute to susceptibility to the later life health effects of iAs.

RECENT FINDINGS

Studies in animal models, as well as human population-based studies, have established that prenatal and early life iAs exposures are associated with long-term effects, and many of these effects display sexually dimorphic responses. As an underlying molecular basis, recent epidemiologic and toxicologic studies have demonstrated that changes to the epigenome may play a key mechanistic role underlying many of the iAs-associated health outcomes. Developmental exposure to iAs results in early and later life health effects. Mechanisms underlying these outcomes are likely complex, and include disrupted key biological pathways with ties to the epigenome. This highlights the importance of continued research, particularly in animal models, to elucidate the important underpinnings (e.g., timing of exposure, metabolism, dose) of these complex health outcomes and to identify the biological mechanisms underlying sexual dimorphism in iAs-associated diseases. Future research should investigate preventative strategies for the protection from the detrimental health endpoints associated with early life exposure to iAs. Such strategies could include potential interventions focused on dietary supplementation for example the adoption of a folate-rich diet.

Prenatal arsenic exposure alters the placental expression of multiple epigenetic regulators in a sex-dependent manner

BACKGROUND

Prenatal exposure to arsenic has been linked to a range of adverse health conditions in later life. Such fetal origins of disease are frequently the result of environmental effects on the epigenome, leading to long-term alterations in gene expression. Several studies have demonstrated effects of prenatal arsenic exposure on DNA methylation; however the impact of arsenic on the generation and decoding of post-translational histone modifications (PTHMs) is less well characterized, and has not been studied in the context of prenatal human exposures.

METHODS

In the current study, we examined the effect of exposure to low-to-moderate levels of arsenic in a US birth cohort, on the expression of 138 genes encoding key epigenetic regulators in the fetal portion of the placenta. Our candidate genes included readers, writers and erasers of PTHMs, and chromatin remodelers.

RESULTS

Arsenic exposure was associated with the expression of 27 of the 138 epigenetic genes analyzed. When the cohort was stratified by fetal sex, arsenic exposure was associated with the expression of 40 genes in male fetal placenta, and only 3 non-overlapping genes in female fetal placenta. In particular, we identified an inverse relationship between arsenic exposure and expression of the gene encoding the histone methyltransferase, PRDM6 (p < 0.001). Mutation of PRDM6 has been linked to the congenital heart defect, patent ductus arteriosus.

CONCLUSIONS

Our findings suggest that prenatal arsenic exposure may have sex-specific effects on the fetal epigenome, which could plausibly contribute to its subsequent health impacts.

A Prospective Cohort Study Examining the Associations of Maternal Arsenic Exposure With Fetal Loss and Neonatal Mortality

Arsenic crosses the placenta, possibly increasing the risk of adverse reproductive outcomes. We aimed to examine the association between maternal arsenic exposure and fetal/neonatal survival using data from a prospective cohort study of 1,616 maternal-infant pairs recruited at a gestational age of ≤16 weeks in Bangladesh (2008-2011). Arsenic concentration in maternal drinking water was measured at enrollment. Extended Cox regression (both time-dependent coefficients and step functions) was used to estimate the time-varying association between maternal arsenic exposure and fetal/neonatal death (all mortality between enrollment and 1 month after birth). In a sensitivity analysis, we assessed gestational arsenic exposure using maternal urine samples taken at enrollment. We observed 203 fetal losses and 20 neonatal deaths. Higher arsenic exposure was associated with a slightly decreased mortality rate up to the middle of the second trimester, and then the mortality rate switched directions around 20 weeks' gestation. In the step function model, the hazard ratios for combined mortality (fetal loss and neonatal death) per unit increase in the natural log of drinking water arsenic concentration (μg/L) ranged from 1.35 (95% CI: 1.08, 1.69) in weeks 25-28 to 0.81 (95% CI: 0.65, 1.02) in weeks 9-12. This nonlinear association suggests that arsenic may exert survival pressure on developing fetuses, potentially contributing to survival bias, and may also indicate that arsenic toxicity differs by fetal developmental stage.

Placental concentrations of essential, toxic, and understudied metals and relationships with birth outcomes in Chattanooga, TN

BACKGROUND

Comprehensive examinations of placental metal concentrations and correlations with infant parameters are under-investigated. Chattanooga, Tennessee's consistently high incidence of low birth weight and potential for metal exposure provides an ideal opportunity to investigate potential correlations.

OBJECTIVES

To investigate the associations between a wide variety of metals in placental tissue and multiple infant parameters.

METHODS

A total of 31 elements were screened via ICP-MS in 374 individual placental samples. Of those, 14 were quantifiable in > 86% of the samples. We examined correlations between metal concentrations and infant parameters (birth weight, gestational age, birth weight centile, placental weight, birth length and head circumference). We fit multivariable regression models to estimate the covariate-adjusted associations of birth weight with ln-transformed concentrations of each of the 14 metals and used generalized additive models to examine nonlinear relationships.

RESULTS

Some of the strongest relationships with infant parameters came from several lesser-studied metals. Placental rhodium concentrations were negatively correlated with almost all infant parameters. In the fully adjusted regression model, birth weight was significantly associated with several metals. On an IQR (25th to the 75th percentile) basis, estimated changes in birthweight were: for cobalt (82.5 g, IQR=6.05 µg/kg, p = 0.006), iron (-51.5 g, IQR = 171800 µg/kg, p = 0.030), manganese (-27.2 g, IQR=152.1 µg/kg, p = 0.017), lead (-72.7 g, IQR=16.55 µg/kg, p = 0.004) and rhodium (-1365.5 g, IQR = 0.33 µg/kg, p < 0.001). Finally, a generalized additive model showed significant nonlinear relationships between birth weight and concentrations of Co and Rh.

CONCLUSIONS

Our comprehensive examination of placental metals illustrate many strong associations between lesser-studied metals and infant parameters. These data, in combination with our correlations of well-studied metals, illustrate a need to consider in utero exposure to a broad array of metals when considering fetal development.

Effects of trimester-specific exposure to vanadium on ultrasound measures of fetal growth and birth size: a longitudinal prospective prenatal cohort study

BACKGROUND

Identification of windows of heightened vulnerability to environmental factors has substantial public health implications. Prenatal exposure to vanadium has been linked to adverse birth outcomes; however, critical windows for such exposure during fetal growth remain unknown. We aimed to assess trimester-specific associations of vanadium exposure with ultrasound measures of fetal growth and birth size in a Chinese longitudinal cohort.

METHODS

The present study was embedded in our ongoing prospective prenatal cohort study at the Wuhan Women and Children Medical Care Center (Wuhan, Hubei, China). Pregnant women were eligible for inclusion if they provided signed informed consent and were less than 16 weeks pregnant with a single gestation, and agreed to take in-person interviews, undergo ultrasound examinations, and provide blood and urine samples. We collected urine samples and measured urinary vanadium concentrations using inductively coupled plasma mass spectrometry. We calculated SD scores for ultrasound-measured biparietal diameter, head circumference, occipitofrontal diameter, abdominal circumference, femur length, and estimated fetal weight at 16, 24, and 31 weeks of gestation. We applied linear regressions with generalised estimating equations to estimate associations of urinary vanadium concentrations in each trimester with ultrasound-measured fetal growth parameters or neonatal size at birth.

FINDINGS

As of Oct 12, 2016, we recruited 3075 women who were non-smokers and non-drinkers during pregnancy, provided up to three urine samples during the first, second, and third trimesters, and gave birth to live singletons without birth defects. We excluded women who did not provide information on ultrasound measurements (n=20) or who only had one ultrasound measurement of fetal crown-rump length at the first trimester (n=14). We excluded another 16 women because they had missing values for confounding variables, leaving 3025 women retained in the study. Every doubling of urinary vanadium concentration in the first trimester was associated with a significant increase in femur length (adjusted percentage change 6·4%, 95% CI 0·7 to 12·1) at 16 weeks of gestation and reductions in biparietal diameter (-4·2%, -8·2 to -0·1), head circumference (-6·0%, -10·1 to -1·9), occipitofrontal diameter (-5·7%, -9·9 to -1·5), and abdominal circumference (-5·3%, -9·4 to -1·2) at 31 weeks of gestation. Every doubling of urinary vanadium concentration in the second trimester was significantly associated with reductions in SD scores for head circumference (-7·2%, -14·1 to -0·3) and abdominal circumference (-6·9%, -13·8 to -0·1) at 31 weeks of gestation. The highest quartile of urinary vanadium concentration (>1·18 μg/L) in the first trimester, when compared with the lowest quartile (≤0·60 μg/L), was associated with a mean decrease in birthweight of 12·6 g (95% CI 2·5-22·8; p_trend=0·0055) and a mean decrease in ponderal index of 0·07 kg/m³ (0·01-0·12; p_trend=0·0053). Moreover, newborns with restricted birth size had higher vanadium exposure in the first and third trimesters.

INTERPRETATION

Vanadium might be toxic to humans and impair fetal growth. The first, early second, and late third trimesters could be critical windows for heightened vulnerability to vanadium for fetal growth. Our findings require further investigation in other populations.

FUNDING

National Key R&D Plan of China, National Natural Science Foundation of China, and Fundamental Research Funds for the Central Universities, Huazhong University of Science and Technology.

Postnatal low-concentration arsenic exposure induces autism-like behavior and affects frontal cortex neurogenesis in rats

This study aimed to explore the effects of postnatal low-concentration arsenic exposure on learning, social skills and frontal cortex neurogenesis in rats. Water-based arsenic exposure rat models were established on postnatal days 4-10 (P4-P10). The experimental animals were divided into four groups: the control group, a 15 μg/L As₂O₃ water group, a 30 μg/L As₂O₃ water group, and a 45 μg/L As₂O₃ water group. Cognitive function was examined with the Morris water maze, anxiety-like behavior with the open field test and light-dark box test, and social skills with a social interaction test. The frontal cortices of pups from each experimental group were sectioned at various time points after arsenic exposure. The morphologies and neurogenesis of the neurons in the frontal cortices were observed by hematoxylin-eosin staining, Nissl staining, and doublecortin (DCX) immunostaining. Significant positive correlations between arsenic concentration and deficits in learning and social skills were found, and the arsenic exposure groups showed significant increases in anxiety-like behavior compared with the control group (all Ps<0.05). Abnormal morphologic changes in the external granular layer and external pyramidal layer were positively correlated with the water arsenic concentration in the acute phase of arsenic exposure. However, at five weeks after arsenic exposure, the frontal cortex morphology was restored. Moreover, immunohistochemistry revealed that compared to the control group, the groups that were exposed to arsenic exhibited significantly higher levels of DCX expression in the external granular and external pyramidal layers (all Ps<0.001). Furthermore, the 30 μg/L and 45 μg/L arsenic exposure groups still showed some DCX expression at five weeks after exposure. In conclusion, postnatal low-concentration arsenic exposure impaired learning and social skills and increased anxiety-like behaviors, and abnormal frontal cortex neurogenesis may be the mechanism underlying these effects.

In utero exposure to arsenic in tap water and congenital anomalies: A French semi-ecological study

INTRODUCTION

Congenital anomalies (CA) are responsible for high rates of mortality and long-term disabilities. Research on their risk factors including environmental factors is needed. Studies on exposure to arsenic (As) in tap water and the risk of CA have not provided conclusive evidence, particularly when levels of exposure were low (from 10 to 50 μg As/L). The main objective of this study was to assess the association between exposure to As in tap water and the risk of any major CA. The secondary objectives were to assess this association for the most common types of congenital anomalies (in the heart, musculoskeletal, urinary and nervous systems).

METHODS

A semi-ecological study was conducted from births recorded at the University Hospital of Clermont-Ferrand, France, in 2003, 2006 and 2010. The medico-obstetric data were available at individual level. Children with congenital anomalies were identified from the database of the regional registry of congenital anomalies: the Centre d'Etudes des Malformations Congénitales Auvergne (CEMC-Auvergne). As exposure was estimated from the concentrations of As measured during sanitary control of tap water supplied in the mothers' commune of residence (aggregate data). French guidelines for As in tap water were used to identify the two groups: "≥ 10 μg As/L group" and "[0-10) μg As/L group". Multivariable logistic regression models were fit.

RESULTS

5263 children (5.1% with a CA) were included. In stratified analysis by gender of the child, positive associations between As exposure exceeding 10 μg/L and risk of any major CA (adjusted OR = 2.41; 95%CI: 1.36-4.14) and of congenital heart anomalies (adjusted OR = 3.66; 95%CI: 1.62-7.64) were only shown for girls. No association was found for boys.

CONCLUSION

This French semi-ecological study provides additional arguments for the association between exposure to As exceeding 10 μg/L in tap water and the risk of CA especially in a context of low exposure. Further studies are needed to better understand the interaction between arsenic exposure and child gender.

Maternal arsenic exposure and birth outcomes: A birth cohort study in Wuhan, China

Maternal arsenic exposure leads to adverse birth outcomes, but the critical window of this susceptibility keeps unclear. To determine whether the associations between maternal arsenic exposure and birth outcomes were trimester-specific, we conducted a birth cohort study of 1390 women from 2014 to 2016 in Wuhan, China. We examined associations between total urinary arsenic concentrations in three trimesters and birth weight, birth length and the risk of small for gestational age (SGA), and the differences of these associations across trimesters using generalized estimating equations. Maternal urinary arsenic concentrations varied across trimesters and were weakly correlated. Arsenic concentrations in the 3rd trimester, but not in the 1st and 2nd trimesters, were associated with birth outcomes. For each doubling of arsenic levels in the 3rd trimester, birth weight was decreased 24.27 g (95% confidence interval (CI): -46.99, -1.55), birth length was decreased 0.13 cm (95% CI: -0.22, -0.04), and the risk for SGA birth was increased 25% (95% CI: 1.03, 1.49). Further, stratified analyses indicated that these associations were only observed in female infants. Our findings indicate maternal arsenic levels in the 3rd trimester seemed to have significant impacts on birth outcomes, and also emphasize the public health interventions relevance to arsenic exposure in late pregnancy.

Dietary intake and urinary metals among pregnant women in the Pacific Northwest

Pregnancy is a period when the mother and her offspring are susceptible to the toxic effects of metals. We investigated associations of intake of frequently consumed foods with urinary metals concentrations among pregnant women in the Pacific Northwest. We measured urinary cadmium (U-Cd), arsenic (U-As) and molybdenum (U-Mo) concentrations from spot urine samples in early pregnancy (15 weeks of gestation, on average) among 558 women from Seattle and Tacoma, Washington. We assessed periconceptional dietary intake using a semi-quantitative food frequency questionnaire (FFQ). We also determined early pregnancy zinc concentrations in serum. Statistical analyses involved multivariable linear regression models, adjusted for smoking status, age, race/ethnicity, multivitamin and supplement use, education, estimated total energy intake, and gravidity. The geometric mean and range in μg/g creatinine for U-Cd, U-As and U-Mo were 0.29 (0.1-8.2), 18.95 (3-550), and 72.1 (15-467), respectively. U-Cd was positively associated with dietary zinc intake (P-value = 0.004) and serum zinc (P-value<0.001) while it was negatively associated with coffee intake (P-value = 0.03). U-As was positively associated with dietary fish [(Lean fish, fatty fish, shellfish and non-fried fish) (P-values<0.01)], selenium (P-value = 0.004), zinc (P-value = 0.017), vegetables (P-value = 0.004), and low-fat yogurt (P-value = 0.03). Women who reported higher intake of dietary magnesium (Mg)(P-value = 0.04), insoluble fiber (P-value = 0.03), and low-fat yogurt (P-value = 0.04) had higher U-Mo concentrations. Our study suggests that vegetables, fish, fiber and yogurt might be significant dietary sources of metals. Future studies aimed at investigating the risk of exposure to metals from other various food sources among reproductive-age and pregnant women are needed.

Dose and Diet - Sources of Arsenic Intake in Mouse in Utero Exposure Scenarios

In humans, early life exposure to inorganic arsenic is associated with adverse health effects. Inorganic arsenic in utero or in early postnatal life also produces adverse health effects in offspring of pregnant mice that consumed drinking water containing low part per billion levels of inorganic arsenic. Because aggregate exposure of pregnant mice to inorganic arsenic from both drinking water and food has not been fully evaluated in experimental studies, quantifying arsenic exposure of the developing mouse is problematic. Here, we determined levels of total arsenic and arsenic species in natural ingredient rodent diets that are composed of many plant and animal-derived foodstuffs and in a purified ingredient rodent diet that is composed of a more restricted mixture of foodstuffs. In natural ingredient diets, total arsenic levels ranged from ∼60 to ∼400 parts per billion, and in the purified ingredient diet, total arsenic level was 13 parts per billion. Inorganic arsenic was the predominant arsenic species in trifluoroacetic acid extracts of each diet. Various exposure scenarios were evaluated using information on inorganic arsenic levels in diet and drinking water and on daily food and water consumption of pregnant mice. In a scenario in which pregnant mice consumed drinking water with 10 parts per billion of inorganic arsenic and a natural ingredient diet containing 89 parts per billion of inorganic arsenic, drinking water contributed only ∼20% of inorganic arsenic intake. Quantitation of arsenic species in diets used in studies in which drinking water is the nominal source of arsenic exposure provides more accurate dosimetry and improves understanding of dose-response relations. Use of purified ingredient diets will minimize the discrepancy between the target dosage level and the actual dosage level attained in utero exposure studies designed to evaluate effects of low level exposure to inorganic arsenic.

Maternal and infant inflammatory markers in relation to prenatal arsenic exposure in a U.S. pregnancy cohort

INTRODUCTION

Accumulating evidence indicates that arsenic (As), a potent environmental toxicant, may increase cardiovascular disease risk and adversely affect endothelial function at high levels of exposure. Pregnancy is a vulnerable time for both mother and child; however, studies examining the association between prenatal As exposure and plasma biomarkers of inflammation and endothelial function in mothers and newborns are lacking.

METHODS

We examined maternal urinary As levels at gestational weeks 24-28 and levels of inflammatory biomarkers in plasma from 563 pregnant women and 500 infants' cord blood. We assessed a multiplexed panel of circulating inflammatory and endothelial function markers, including tumor necrosis factor alpha (TNFα), monocyte chemoattractant protein 1 (MCP1), intercellular adhesion molecule (ICAM1) and vascular cell adhesion molecule (VCAM1).

RESULTS

Compared with the bottom tertile, the highest tertile of maternal urinary As during pregnancy was associated with a 145.2ng/ml (95% CI 4.1, 286.3; p=0.04) increase in cord blood ICAM1 and 557.3ng/ml (95% CI -56.4, 1171.1; p=0.09) increase in cord blood VCAM1. Among mothers, the highest tertile of maternal urinary As during pregnancy was related to a 141.8ng/ml (95% CI 26.1, 257.5; p=0.02) increase maternal plasma VCAM1 levels. Urinary As was unrelated to MCP1 or TNFα in maternal plasma and cord blood. In structural equation models, the association between maternal urinary As and infant VCAM was mediated by maternal levels of VCAM (βmediation: 0.024, 95% CI: 0.002, 0.050).

CONCLUSION

Our observations indicate that As exposure during pregnancy may affect markers of vascular health and endothelial function in both pregnant women and children, and suggest further investigation of the potential impacts on cardiovascular health in these susceptible populations.

The aquaglyceroporin AQP9 contributes to the sex-specific effects of in utero arsenic exposure on placental gene expression

BACKGROUND

Sex-specific factors play a major role in human health and disease, including responses to environmental stresses such as toxicant exposure. Increasing evidence suggests that such sex differences also exist during fetal development. In a previous report using the resources of the New Hampshire Birth Cohort Study (NHBCS), we found that low-to-moderate in utero exposure to arsenic, a highly toxic and widespread pollutant, was associated with altered expression of several key developmental genes in the fetal portion of the placenta. These associations were sex-dependent, suggesting that in utero arsenic exposure differentially impacts male and female fetuses. In the present study, we investigated the molecular basis for these sex-specific responses to arsenic.

METHODS

Using NanoString technology, we further analyzed the fetal placenta samples from the NHBCS for the expression of genes encoding arsenic transporters and metabolic enzymes. Multivariable linear regression analysis was used to examine their relationship with arsenic exposure and with key developmental genes, after stratification by fetal sex.

RESULTS

We found that maternal arsenic exposure was strongly associated with expression of the AQP9 gene, encoding an aquaglyceroporin transporter, in female but not male fetal placenta. Moreover, AQP9 expression associated with that of a subset of female-specific arsenic-responsive genes.

CONCLUSIONS

Our results suggest that AQP9 is upregulated in response to arsenic exposure in female, but not male, fetal placenta. Based on these results and prior studies, increased AQP9 expression may lead to increased arsenic transport in the female fetal placenta, which in turn may alter the expression patterns of key developmental genes that we have previously shown to be associated with arsenic exposure. Thus, this study suggests that AQP9 may play a role in the sex-specific effects of in utero arsenic exposure.

Embryonic-only arsenic exposure in killifish (Fundulus heteroclitus) reduces growth and alters muscle IGF levels one year later

Arsenic is a contaminant of drinking water and crops in many parts of the world. Epidemiological studies have shown that arsenic exposure is linked to decreased birth weight, weight gain, and proper skeletal muscle function. The goal of this study was to use killifish (Fundulus heteroclitus) as a model to determine the long-term effects of embryonic-only arsenic exposure on muscle growth and the insulin-like growth factor (IGF) pathway. Killifish embryos were exposed to 0, 50, 200 or 800ppb As^III from fertilization until hatching. Juvenile fish were reared in clean water and muscle samples were collected at 16, 28, 40 and 52 weeks of age. There were significant reductions in condition factors, ranging from 12 to 17%, in the fish exposed to arsenic at 16, 28 and 40 weeks of age. However, by 52 weeks, no significant changes in condition factors were seen. Alterations in IGF-1R and IGF-1 levels were assessed as a potential mechanism by which growth was reduced. While there no changes in hepatic IGF-1 transcripts, skeletal muscle cells can also produce their own IGF-1 and/or alter IGF-1 receptor levels to help enhance growth. After a 200 and 800ppb embryonic exposure, fish grown in clean water for 16 weeks had IGF-1R transcripts that were 2.8-fold and 2-fold greater, respectively, than unexposed fish. Through 40 weeks of age, IGF1-R remained elevated in the 200ppb and 800ppb embryonic exposure groups by 1.8-3.9-fold, while at 52 weeks of age, IGF-1R levels were still significantly increased in the 800ppb exposure group. Skeletal muscle IGF-1 transcripts were also significantly increased by 1.9-5.1 fold through the 52 weeks of grow-out in clean by water in the 800ppb embryonic exposure group. Based on these results, embryonic arsenic exposure has long-term effects in that it reduces growth and increases both IGF-1 and IGF-1R levels in skeletal muscle even 1year after the exposure has ended.

Determine Multiple Elements Simultaneously in the Sera of Umbilical Cord Blood Samples-a Very Simple Method

Analyzing the concentrations of heavy metals in the sera of umbilical cord blood samples can provide useful information about prenatal exposure to environmental agents. An analytical method based on ICP-MS to simultaneously determine multiple elements in umbilical cord blood samples was developed for assessing the in utero exposure to metallic and metalloid elements. The method only required as little as 100 μL of serum diluted 1:25 for direct analysis. Matrix-matched protocol was used to eliminate mass matrix interference and kinetic energy discrimination mode was used to eliminate the polyatomic ion interference. The assay was completed on average within 4 min with the detection limits ranging from 0.0002 to 44.4 μg/L for all the targeted elements. The detection rates for most of elements were 100 % other than cadmium (Cd), lead (Pb), and mercury (Hg). The testing results of the certified reference materials were ideal. The method is simple and sensitive, so it is suitable for the monitoring of large quantities of samples.

Human exposure to organic arsenic species from seafood

Seafood, including finfish, shellfish, and seaweed, is the largest contributor to arsenic (As) exposure in many human populations. In contrast to the predominance of inorganic As in water and many terrestrial foods, As in marine-derived foods is present primarily in the form of organic compounds. To date, human exposure and toxicological assessments have focused on inorganic As, while organic As has generally been considered to be non-toxic. However, the high concentrations of organic As in seafood, as well as the often complex As speciation, can lead to complications in assessing As exposure from diet. In this report, we evaluate the presence and distribution of organic As species in seafood, and combined with consumption data, address the current capabilities and needs for determining human exposure to these compounds. The analytical approaches and shortcomings for assessing these compounds are reviewed, with a focus on the best practices for characterization and quantitation. Metabolic pathways and toxicology of two important classes of organic arsenicals, arsenolipids and arsenosugars, are examined, as well as individual variability in absorption of these compounds. Although determining health outcomes or assessing a need for regulatory policies for organic As exposure is premature, the extensive consumption of seafood globally, along with the preliminary toxicological profiles of these compounds and their confounding effect on assessing exposure to inorganic As, suggests further investigations and process-level studies on organic As are needed to fill the current gaps in knowledge.

Developmental Windows of Susceptibility to Inorganic Arsenic: A Survey of Current Toxicologic and Epidemiologic Data

Globally, millions of people are exposed to elevated levels of inorganic arsenic (iAs) via drinking water. Exposure to iAs is associated with a wide range of negative health outcomes, including cancers, skin lesions, neurological impairment, cardiovascular diseases, and an increased susceptibility to infection. Among those exposed to iAs, the developing fetus and young children represent particularly sensitive subpopulations. Specifically, it has been noted in animal models and human populations that prenatal and early life iAs exposures are associated with diseases occurring during childhood and later in life. Recent epidemiologic and toxicologic studies have also demonstrated that epigenetic alterations may play a key mechanistic role underlying many of the iAs-associated health outcomes, including the carcinogenic and immunologic effects of exposure. This review summarizes some of the key studies related to prenatal and early life iAs exposure and highlights the complexities in isolating the precise developmental windows of exposure associated with these health outcomes.

Relation between in Utero Arsenic Exposure and Birth Outcomes in a Cohort of Mothers and Their Newborns from New Hampshire

BACKGROUND

Studies suggest that arsenic exposure influences birth outcomes; however, findings are mixed.

OBJECTIVE

We assessed in utero arsenic exposure in relation to birth outcomes and whether maternal prepregnancy weight and infant sex modified the associations.

METHODS

Among 706 mother-infant pairs exposed to low levels of arsenic through drinking water and diet, we assessed in utero arsenic exposure using maternal second-trimester urinary arsenic, maternal prepregnancy weight through self-report, and birth outcomes from medical records.

RESULTS

Median (interquartile range) of total urinary arsenic [tAs; inorganic arsenic (iAs) + monomethylarsonic acid (MMA) + dimethylarsinic acid (DMA)] was 3.4 μg/L (1.7-6.0). In adjusted linear models, each doubling of tAs was associated with a 0.10-cm decrease (95% CI: -0.19, -0.01) in head circumference. Results were similar for MMA and DMA. Ln(tAs) and ln(DMA) were positively associated with birth length in infant males only; among males, each doubling of tAs was associated with a 0.28-cm increase (95% CI: 0.09, 0.46) in birth length (pinteraction = 0.04). Results were similar for DMA. Additionally, arsenic exposure was inversely related to ponderal index, and associations differed by maternal weight. Each ln(tAs) doubling of tAs was associated with a 0.55-kg/m3 lower (95% CI: -0.82, -0.28, p < 0.001) ponderal index for infants of overweight/obese, but not normal-weight, mothers (pinteraction < 0.01). Finally, there was a significant interaction between maternal weight status, infant sex, and arsenic exposure on birth weight (pinteraction = 0.03). In girls born of overweight/obese mothers, each doubling of tAs was associated with a 62.9-g decrease (95% CI: -111.6, -14.2) in birth weight, though the association was null in the other strata.

CONCLUSIONS

Low-level arsenic exposure may affect fetal growth, and the associations may be modified by maternal weight status and infant sex.

CITATION

Gilbert-Diamond D, Emond JA, Baker ER, Korrick SA, Karagas MR. 2016. Relation between in utero arsenic exposure and birth outcomes in a cohort of mothers and their newborns from New Hampshire. Environ Health Perspect 124:1299-1307; http://dx.doi.org/10.1289/ehp.1510065.

Systematic review of differential inorganic arsenic exposure in minority, low-income, and indigenous populations in the United States

Inorganic arsenic (iAs) is a human carcinogen and associated with cardiovascular, respiratory, and skin diseases. Natural and anthropogenic sources contribute to low concentrations of iAs in water, food, soil, and air. Differential exposure to environmental hazards in minority, indigenous, and low income populations is considered an environmental justice (EJ) concern, yet it is unclear if higher iAs exposure occurs in these populations. A systematic review was conducted to evaluate evidence for differential iAs exposure in the United States (US). The peer-reviewed literature was searched for studies that (1) estimated iAs exposure based on environmental concentrations of iAs in water, food, soil, or iAs biomarkers and (2) examined iAs exposure in minority, indigenous, and low income US populations. Five studies were identified that estimated exposures and provided demographic information about EJ populations. These studies reported arsenic concentrations in water, soil, or food to estimate exposure, with varied evidence of differential exposure. Additionally, six studies were identified that suggested potential arsenic exposure from environmental sources including soil, rice, private well-water, and fish, but did not report data stratified by demographic information. Evidence across these 11 studies was qualitatively integrated to draw conclusions about differential iAs exposure. The total body of evidence is limited by lack of individual exposure measures, lack of iAs concentration data, and insufficient comparative demographic data. Based upon these data gaps, there is inadequate evidence to conclude whether differential exposure to iAs is an EJ concern in the US.

Association of Rice and Rice-Product Consumption With Arsenic Exposure Early in Life

IMPORTANCE

Rice-a typical first food and major ingredient in various infant foods-contains inorganic arsenic (As), but the extent of As exposure from these foods has not been well characterized in early childhood.

OBJECTIVE

To determine the types and frequency of rice and rice-containing products consumed by infants in the first year of life and the association with As biomarker concentrations.

DESIGN, SETTING, AND PARTICIPANTS

Included were infants from singleton births of pregnant women enrolled in the New Hampshire Birth Cohort Study from 2011 to 2014 whose parents were interviewed during their first year of life. Enrolled women from selected clinics were aged 18 to 45 years, living in the same residence since their last menstrual period, in households served by a private water system, and had no plans to move during pregnancy. Data on infants' intake of rice and rice products were collected from interviews with their parents at 4, 8, and 12 months' follow-up and from a 3-day food diary at 12 months from March 2013 to August 2014.

EXPOSURES

Infants' intake of rice and rice products.

MAIN OUTCOMES AND MEASURES

Total urinary As and the sum of As species measured using inductively coupled mass spectrometry and high-performance liquid chromatography with inductively coupled mass spectrometry. Commonly reported infant rice snacks were tested for As.

RESULTS

We obtained dietary data on 759 of 951 infants (79.8% participation rate). Of these, 391 infants (51.7%) were male, and the mean (SD) gestational age was 39.4 (1.7) weeks. An estimated 80% were introduced to rice cereal during their first year. At 12 months, 32.6% of infants (42 of 129) were fed rice snacks. Among infants aged 12 months who did not eat fish or seafood, the geometric mean total urinary As concentrations were higher among those who ate infant rice cereal (9.53 µg/L) or rice snacks (4.97 µg/L) compared with those who did not eat rice or rice products (2.85 µg/L; all P < .01). Infant rice snacks contained between 36 and 568 ng/g of As and 5 to 201 ng/g of inorganic As.

CONCLUSIONS AND RELEVANCE

Our findings indicate that intake of rice cereal and other rice-containing foods, such as rice snacks, contribute to infants' As exposure and suggest that efforts should be made to reduce As exposure during this critical phase of development.

Environmental pollutants and child health-A review of recent concerns

In recent years, many new studies have evaluated associations between environmental pollutants and child health. This review aims to provide a broad summary of this literature, comparing the state of epidemiological evidence for the effects of a wide range of environmental contaminants (air pollutants, heavy metals, organochlorine compounds, perfluoroalkyl substances, polybrominated diphenyl ethers, pesticides, phthalates and bisphenol A) on child health outcomes. The review addresses effects on foetal growth and prematurity, neurodevelopment, respiratory and immune health, and childhood growth and obesity. Findings of recent prospective studies and meta-analyses have corroborated previous good evidence, often at lower exposure levels, for effects on foetal growth of air pollution and polychlorinated biphenyls (PCBs), for neurotoxic effects of lead, methylmercury, PCBs and organophosphate pesticides, and for respiratory health effects of air pollution. Moderate evidence has emerged for a potential role of environmental pollutants in attention deficit hyperactivity disorder and autism (lead, PCBs, air pollution), respiratory and immune health (dichlorodiphenyldichloroethylene - DDE - and PCBs), and obesity (DDE). In addition, there is now moderate evidence that certain chemicals of relatively recent concern may be associated with adverse child health outcomes, specifically perfluorooctanoate and foetal growth, and polybrominated diphenyl ethers and neurodevelopment. For other chemicals of recent concern, such as phthalates and bisphenol A, the literature is characterised by large inconsistencies preventing strong conclusions. In conclusion, since most of the recent literature evaluates common exposures in the general population, and not particularly high exposure situations, this accumulating body of evidence suggests that the unborn and young child require more protection than is currently provided. Large, coordinated research efforts are needed to improve understanding of long-term effects of complex chemical mixtures.

Low level arsenic contaminated water consumption and birth outcomes in Romania-An exploratory study

Women are exposed to drinking water with low arsenic concentrations (<10.0μg/L) worldwide, yet little work has been done to assess the risk. To begin to address this data gap, we conducted an exploratory study of birth outcomes in Timis County, Romania. We prospectively followed 122 women with singleton deliveries, for whom we constructed individual exposure indicators using self-reported water consumption weighted by arsenic measured in drinking water sources. There were no overall confounder-adjusted effects for arsenic exposure on birth outcomes. Yet, higher average arsenic (10μg/L) was associated with a -2.45 lower birth weight Z-score (P=0.021) and a -1.17 shorter birth length Z-score (P=0.029) among smokers. Higher average iAs (10μg/L) was also associated with smaller ponderal index in boys (P=0.023). Our results suggest smoking may potentiate an otherwise benign arsenic exposure. A larger, more definitive biomarker-based study is needed to investigate the potential risks in conjunction with smoking.