Prenatal Metal Exposures and Infants' Developmental Outcomes in a Navajo Population

Integrating Data Across Multiple Sites in the Northeastern United States to Examine Associations Between a Prenatal Metal Mixture and Child Cognition

We applied a novel hierarchical Bayesian weighted quantile sum (HBWQS) regression to combine data across 3 study sites to examine associations between prenatal exposure to metals and cognitive functioning in childhood. Data from 326 mother-child dyads enrolled in an ongoing cohort study, the Programming of Intergenerational Stress Mechanisms (PRISM) Study, based in New York, New York (recruitment in 2013-2020) and Boston, Massachusetts (recruitment 2011-2013), and the First Thousand Days of Life (FTDL) cohort study (recruitment 2012-2019), based in northern Virginia, were used. Arsenic, cadmium, manganese, lead, and antimony were measured in urine collected during pregnancy. Cognitive functioning was assessed in children aged 3-11 years using the National Institutes of Health Toolbox Cognition Battery. The HBWQS regression showed a negative association between the urinary metal mixture and the Cognition Early Childhood Composite Score in the PRISM New York City (β = -3.67, 95% credible interval (CrI): -7.61, -0.01) and FTDL (β = -3.76, 95% CrI: -7.66, -0.24) samples, with a similar trend in the PRISM Boston sample (β = -3.24, 95% CrI: -6.77, 0.144). We did not detect these associations in traditionally pooled models. HBWQS regression allowed us to account for site heterogeneity and detect associations between prenatal metal-mixture exposure and cognitive outcomes in childhood. Given the ubiquity of metals exposure, interventions aimed at reducing prenatal exposure may improve cognitive outcomes in children. This article is part of a Special Collection on Environmental Epidemiology.

Density and proximity of oil and gas wells and concentrations of trace elements in urine, hair, nails and tap water samples from pregnant individuals living in Northeastern British Columbia

BACKGROUND

Oil and gas exploitation can release several contaminants in the environment, including trace elements, with potentially deleterious effects on exposed pregnant individuals and their developing fetus. Currently, there is limited data on pregnant individuals' exposure to contaminants associated with oil and gas activity.

OBJECTIVES

We aimed to 1)measure concentrations of trace elements in biological and tap water samples collected from pregnant individuals participating in the EXPERIVA study; 2)compare with reference populations and health-based guidance values; 3)assess correlations across matrices; and 4)evaluate associations with the density/proximity of oil and gas wells.

METHODS

We collected tap water, hair, nails, and repeated urine samples from 85pregnant individuals, and measured concentrations of 21trace elements. We calculated oil and gas well density/proximity (Inverse Distance Weighting [IDW]) for 4buffer sizes (2.5 km, 5 km, 10 km, no buffer). We performed Spearman's rank correlation analyses to assess the correlations across elements and matrices. We used multiple linear regression models to evaluate the associations between IDWs and concentrations.

RESULTS

Some study participants had urinary trace element concentrations exceeding the 95th percentile of reference values; 75% of participants for V, 29% for Co, 22% for Ba, and 20% for Mn. For a given trace element, correlation coefficients ranged from -0.23 to 0.65 across matrices; correlations with tap water concentrations were strongest for hair, followed by nails, and urine. Positive (e.g., Cu, Cr, Sr, U, Ga, Ba, Al, Cd) and negative (e.g., Fe) associations were observed between IDW metrics and the concentrations of certain trace elements in water, hair, and nails.

SIGNIFICANCE

Our results suggest that pregnant individuals living in an area of oil and gas activity may be more exposed to certain trace elements (e.g., Mn, Sr, Co, Ba) than the general population. Association with density/proximity of wells remains unclear.

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.

Associations between a metal mixture and infant negative affectivity: Effect modification by prenatal cortisol and infant sex

In-utero exposures interact in complex ways that influence neurodevelopment. Animal research demonstrates that fetal sex moderates the impact of joint exposure to metals and prenatal stress measures, including cortisol, on offspring socioemotional outcomes. Further research is needed in humans. We evaluated the joint association of prenatal exposures to a metal mixture and cortisol with infant negative affectivity, considering sex differences. Analyses included 226 (29% White, Non-Hispanic) mother-infant pairs with data on exposures and negative affectivity assessed using the Infant Behavior Questionnaire-Revised in 6-month-olds. Results showed that girls whose mothers had higher cortisol had significantly higher scores of Fear and Sadness with greater exposure to the mixture. Examining higher-order interactions may better elucidate the effects of prenatal exposure to metals and cortisol on socioemotional functioning.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

"Know Your Children, Who They Are, Their Weakness, and Their Strongest Point": A Qualitative Study on Diné Parent Experiences Accessing Autism Services for Their Children

BACKGROUND AND OBJECTIVE

Marked inequities in access to autism services and related health outcomes persist for U.S. children, undermining broader initiatives to advance the population's health. At the intersection of culture, poverty, and ruralness little remains known about autism in many Indigenous communities. This qualitative study on the lived experiences of Navajo (Diné) parents raising a child with autism sought to identify factors affecting access to services.

METHODS

A Diné researcher conducted in-depth interviews with 15 Diné parents of children with autism living in or around the Navajo Nation. A directed content analysis approach was used to identify themes, subthemes, and connections between themes.

RESULTS

Twelve overarching themes emerged on Diné parents' experiences accessing autism diagnostic and treatment services, as well as ways access to autism services can be improved. The following themes were related to diagnosis: the diagnostic process was often emotionally fraught; long wait times of up to years for diagnostic services were commonplace; limited clinician training and cultural humility impeded access to diagnostic services; and adequate health insurance, Indian Health Service referrals, care coordination, financial aid for travel, and efficient evaluation facilitated diagnosis. Themes on treatment access were as follows: parent perceptions of the extent to which an autism service helped their child affected access; social support helped parents to access treatment; obtaining referrals and care coordination influenced treatment access; treatment costs affected access; and service availability and geographic proximity impacted treatment access. Themes on ways to improve access to autism services were as follows: greater autism awareness is needed; autism-focused support groups may be helpful; and increased availability and quality of autism services across and around the Navajo Nation is paramount.

CONCLUSIONS

Diné parents' access to autism services was dynamically affected by sociocultural factors that must be addressed in future health equity-oriented initiatives.

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.

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 exposure to environmental pro-oxidants induces mitochondria-mediated epigenetic changes: a cross-sectional pilot study

Mitochondria play a central role in maintaining cellular and metabolic homeostasis during vital development cycles of foetal growth. Optimal mitochondrial functions are important not only to sustain adequate energy production but also for regulated epigenetic programming. However, these organelles are subtle targets of environmental exposures, and any perturbance in the defined mitochondrial machinery during the developmental stage can lead to the re-programming of the foetal epigenetic landscape. As these modifications can be transferred to subsequent generations, we herein performed a cross-sectional study to have an in-depth understanding of this intricate phenomenon. The study was conducted with two arms: whereas the first group consisted of in utero pro-oxidant exposed individuals and the second group included controls. Our results showed higher levels of oxidative mtDNA damage and associated integrated stress response among the exposed individuals. These disturbances were found to be closely related to the observed discrepancies in mitochondrial biogenesis. The exposed group showed mtDNA hypermethylation and changes in allied mitochondrial functioning. Altered expression of mitomiRs and their respective target genes in the exposed group indicated the possibilities of a disturbed mitochondrial-nuclear cross talk. This was further confirmed by the modified activity of the mitochondrial stress regulators and pro-inflammatory mediators among the exposed group. Importantly, the disturbed DNMT functioning, hypermethylation of nuclear DNA, and higher degree of post-translational histone modifications established the existence of aberrant epigenetic modifications in the exposed individuals. Overall, our results demonstrate the first molecular insights of in utero pro-oxidant exposure associated changes in the mitochondrial-epigenetic axis. Although, our study might not cement an exposure-response relationship for any particular environmental pro-oxidant, but suffice to establish a dogma of mito-epigenetic reprogramming at intrauterine milieu with chronic illness, a hitherto unreported interaction.

Lung-Based, Exosome Inhibition Mediates Systemic Impacts Following Particulate Matter Exposure

Particulate matter (PM) exposure is a global health issue that impacts both urban and rural communities. Residential communities in the Southwestern United States have expressed concerns regarding the health impacts of fugitive PM from rural, legacy mine-sites. In addition, the recent literature suggests that exosomes may play a role in driving toxicological phenotypes following inhaled exposures. In this study, we assessed exosome-driven mechanisms and systemic health impacts following inhaled dust exposure, using a rodent model. Using an exosome inhibitor, GW4869 (10 μM), we inhibited exosome generation in the lungs of mice via oropharyngeal aspiration. We then exposed mice to previously characterized inhaled particulate matter (PM) from a legacy mine-site and subsequently assessed downstream behavioral, cellular, and molecular biomarkers in lung, serum, and brain tissue. Results indicated that CCL-2 was significantly upregulated in the lung tissue and downregulated in the brain (p < 0.05) following PM exposure. Additional experiments revealed cerebrovascular barrier integrity deficits and increased glial fibrillary acidic protein (GFAP) staining in the mine-PM exposure group, mechanistically dependent on exosome inhibition. An increased stress and anxiety response, based on the open-field test, was noted in the mine-PM exposure group, and subsequently mitigated with GW4869 intervention. Exosome lipidomics revealed 240 and eight significantly altered positive-ion lipids and negative-ion lipids, respectively, across the three treatment groups. Generally, phosphatidylethanolamine (PE) and phosphatidylcholine (PC) lipids were significantly downregulated in the PM group, compared to FA. In conclusion, these data suggest that systemic, toxic impacts of inhaled PM may be mechanistically dependent on lung-derived, circulating exosomes, thereby driving a systemic, proinflammatory phenotype.

A model for the uptake of advance care planning in older cancer adults: a scoping review

BACKGROUND AND AIMS

Advance care planning (ACP) might assist older cancer patients in expressing their goals, values, and care preferences; yet, the ACP uptake rates in this group are low. The goal of this study is to discover factors that influence ACP uptake in older cancer adults and to construct a model that integrates these factors.

METHODS

Using Arksey and O' Malley's methodology, we systematically searched seven electronic databases of ACP literature in older cancer adults from inception to March 2022. To identify factors linked to ACP uptake in elderly cancer patients, researchers used a pre-piloted extraction form. There were two phases to the thematic analysis of the labeled factors. First, factors were grouped into one of three categories using a directed content analysis approach: patient context, provider context, or mechanism. Second, we took both a deductive and inductive thematic approach to identifying and coding contributing factors in each category to identify themes and subthemes. Deductive coding was undertaken using the Andersen's Behavioral Model of Health Services Utilization. Finally, results were visualized into a conceptual model.

RESULTS

In the including 37 articles, 131 factors were extracted. Thematic analysis of patient context factors (n = 72) showed that ACP uptake in older cancer adults is associated with predisposing characteristics, enabling resources and need. Factors attributed to provider context (n = 28) concerned predisposing characteristics and enabling resources. Mechanism factors (n = 31) are related to perceived value and patient trust, and the C-ACP uptake model was created.

CONCLUSION

ACP uptake in older cancer patients is commonly influenced by patient-provider-related contextual factors, and highlights the fact that ACP uptake is more likely to be mediated through both perceived value and patient trust. This review serves as a resource for providers exploring ACP implementation options in older cancer adults.