Prenatal chemical exposures and child language development

Exploring applications of non-targeted analysis in the characterization of the prenatal exposome

Capturing the breadth of chemical exposures in utero is critical in understanding their long-term health effects for mother and child. We explored methodological adaptations in a Non-Targeted Analysis (NTA) pipeline and evaluated the effects on chemical annotation and discovery for maternal and infant exposure. We focus on lesser-known/underreported chemicals in maternal and umbilical cord serum analyzed with liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). The samples were collected from a demographically diverse cohort of 296 maternal-cord pairs (n = 592) recruited in San Francisco Bay area. We developed and evaluated two data processing pipelines, primarily differing by detection frequency cut-off, to extract chemical features from non-targeted analysis (NTA). We annotated the detected chemical features by matching with EPA CompTox Chemicals Dashboard (n = 860,000 chemicals) and Human Metabolome Database (n = 3140 chemicals) and applied a Kendrick Mass Defect filter to detect homologous series. We collected fragmentation spectra (MS/MS) on a subset of serum samples and matched to an experimental MS/MS database within the MS-Dial website and other experimental MS/MS spectra collected from standards in our lab. We annotated ~72 % of the features (total features = 32,197, levels 1-4). We confirmed 22 compounds with analytical standards, tentatively identified 88 compounds with MS/MS spectra, and annotated 4862 exogenous chemicals with an in-house developed annotation algorithm. We detected 36 chemicals that appear to not have been previously reported in human blood and 9 chemicals that were reported in less than five studies. Our findings underline the importance of NTA in the discovery of lesser-known/unreported chemicals important to characterize human exposures.

Early-Life Exposure to Perfluoroalkyl Substances (PFAS) and Child Language and Communication Development: A Systematic Review

Language development starts during the fetal period when the brain is sensitive to endocrine disruptions from environmental contaminants. This systematic review aims to systematically summarize the existing literature on early-life exposure to PFAS and children's language and communication development, which is an indicator of neurocognitive development. A structured literature search was conducted using three databases, PubMed, Scopus, and CINAHL, last updated in April 2023. The population was defined as children and young adults. PFAS exposure was assessed pre- or postnatally. The outcome was defined as a language and communication ability assessed with validated instruments, parental self-reports, or clinical language disorder diagnoses. In total, 15 studies were identified for subsequent analyses. Thirteen were performed in background-exposed populations and two in highly exposed populations. There were some indications of potential adverse effects; however, these were not consistent across child sex, age of assessment, or PFAS exposure levels. No systematic effect of early-life PFAS exposure on language and communication development was found. These inconclusive findings may partly be explained by the use of general test instruments with limited validity as to children's language and communication development. Further studies over a wider exposure range using specific language test instruments are needed.

The association of prenatal phthalates, organophosphorous pesticides, and organophosphate esters with early child language ability in Norway

BACKGROUND

Prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides have been associated with neurodevelopmental deficits including language ability, however, few studies consider the effect of exposure mixtures and the potential longitudinal detriments over time.

OBJECTIVE

This study examines the influence of prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides, on children's language ability from toddlerhood to the preschool period.

METHODS

This study includes 299 mother-child dyads from Norway in the Norwegian Mother, Father and Child Cohort Study (MoBa). Prenatal exposure to chemicals were assessed at 17 weeks' gestation, and child language skills were assessed at 18 months using the Ages and Stages Questionnaire communication subscale and at preschool age using the Child Development Inventory. We ran two structural equation models to examine the simultaneous influences of chemical exposures on parent-reported and teacher-reported child language ability.

RESULTS

Prenatal organophosphorous pesticides were negatively associated with preschool language ability through language ability at 18 months. Additionally, there was a negative association between low molecular weight phthalates and teacher-reported preschool language ability. There was no effect of prenatal organophosphate esters on child language ability at either 18 months or preschool age.

CONCLUSIONS

This study adds to the literature on prenatal exposure to chemicals and neurodevelopment and highlights the importance of developmental pathways in early childhood.

Lead Exposure Can Affect Early Childhood Development and Could Be Aggravated by Stunted Growth: Perspectives from Mexico

BACKGROUND

Lead can affect early childhood development (ECD) differentially due to nutritional deficiencies that lead to stunted growth, defined as being at least two standard deviations below the average height-for-age. These deficiencies are more frequent among children living in rural locations or with lower socioeconomic status (SES); however, studies at a population level are scarce worldwide. Early childhood development plays a crucial role in influencing a child's health and wellbeing throughout life. Therefore, the aim of this study was to analyze how stunted growth can modify the association between lead exposure and ECD in children from disadvantaged communities.

METHODS

Data were analyzed from the 2018 National Health and Nutrition Survey in localities with fewer than 100,000 inhabitants in Mexico (ENSANUT-100K). Capillary blood lead (BPb) levels were measured using a LeadCare II device and dichotomized as detectable (cutoff point ≥ 3.3 µg/dL) and non-detectable. As a measure of ECD, language development was assessed in n = 1394 children, representing 2,415,000 children aged 12-59 months. To assess the association between lead exposure and language z-scores, a linear model was generated adjusted by age, sex, stunted growth, maternal education, socioeconomic status, area, region (north, center, south), and family care characteristics; afterwards, the model was stratified by stunted growth.

RESULTS

Fifty percent of children had detectable BPb and 15.3% had stunted growth. BPb showed a marginal inverse association with language z-scores (β: -0.08, 95% CI: -0.53, 0.36). Children with detectable BPb and stunted growth had significantly lower language z-scores (β: -0.40, 95% CI: -0.71, -0.10) than those without stunted growth (β: -0.15, 95% CI: -0.36, 0.06).

CONCLUSIONS

Children with stunted growth are more vulnerable to the adverse effects of lead exposure. These results add to previous research calling for action to reduce lead exposure, particularly in children with chronic undernutrition.

Neuropsychological effects and cognitive deficits associated with exposure to mercury and arsenic in children and adolescents of the Mojana region, Colombia

The present study aims to explore the neuropsychological performance and exposure to mercury (Hg) and arsenic (As) in Colombian children and adolescents considering biomarkers in hair and blood. The total sample consisted of 70 participants from the Mojana region, Colombia. A neuropsychological evaluation protocol was used, consisting of 11 internationally recognized tests, with evidence of national validation and use for measurement in neurotoxicology contexts. A 57.1% of the sample presented levels above the reference value according to the USEPA, the WHO, and the ATSDR for total mercury in hair (HgH), blood mercury (HgB), and/or blood arsenic (AsB). The mean values reported for HgH were 1.76 ± 3.1 μg/g (95% CI 1.02-2.50) with ranges between 0.23 and 17.20; for HgB: 4.11 ± 5.93 μg/l (CI 2.69-5.52), ranging between 0.25 and 25.80, and for AsB: 1.96 ± 2.73 (CI 1.31-2.61) ranging between 0.50 and 15.50. In the comparison of groups in relation to the level of exposure, a significant difference was found (p < 0.05) for the subtest The Boston Naming Test (BNT). Correlation analyses found, on the one hand, significant negative relationships in tests integrated within the verbal (CVB) and executive function (EF) components as well as evidence of positive relationships in the manifestation of errors in their performance with the levels of Hg and/or As transformed by biomarker (Log10). In the linear regression analyses it was found that for each increase in the concentration of HgH, HgB, and AsB it is estimated that, both for the models with and without data adjustment, there is a loss of scores in integrated measures within the CVB and EF for the transformed levels of HgH, HgB, and AsB; and an increase in the reported errors in their processing within these functions. According to these results, exposure to mercury and/or arsenic is related with performance in verbal neuropsychological skills and executive functioning.

Evaluation of Heavy Metal (Lead, Mercury, Cadmium, and Manganese) Levels in Blood, Plasma, and Urine of Adolescents With Aggressive Behavior

Background Heavy metals can cause health problems by affecting the biological structure even at very low concentrations. Asymptomatic heavy metal poisoning causes non-specific symptoms such as behavioral disorders, difficulty in learning, and aggressive behaviors. There is also a great concern about the incidence of aggressive behavior among adolescents. A few research studies have concluded that a complex interaction or combination of factors leads to an increased risk of aggressive behavior in adolescents. This study aims to determine the correlation between the heavy metal levels in blood, plasma, and urine and the aggression level in adolescents. Materials and methods Two hundred twenty-eight adolescents between the ages of 13 and 19 were enrolled in the study. Blood, plasma, and urine heavy metal levels of the participants were measured by an inductively coupled plasma mass spectrometer (ICP-MS) device (Model 7700x; Agilent, Santa Clara, CA, USA). Buss and Perry's aggression questionnaire was used to investigate the correlation between heavy metals and aggressive behaviors in adolescents. Results Lead blood (r=0.34, p<.01), lead plasma (r=0.22, p<0.01), lead urine (r=0.31, p<.01), mercury blood (r=0.35, p<0.01), mercury urine (r=0.21, p<0.01), manganese blood (r=0.34, p<0.01), manganese plasma (r=0.33, p<0.01) and manganese urine (r=0.39, p<0.01) were positively correlated with tendency to aggression whereas no significant relationship was found between cadmium in blood, plasma, urine and mercury in plasma with aggression. Conclusion The study showed valuable data to associate a significant relationship between adolescents' aggression levels and heavy metals. There is an undeniable relationship between the health of adolescents and environmental pollution caused by heavy metals. Therefore, taking the necessary measures to prevent environmental heavy metal pollution is crucial for adolescent health.

A Role for Data Science in Precision Nutrition and Early Brain Development

Multimodal brain magnetic resonance imaging (MRI) can provide biomarkers of early influences on neurodevelopment such as nutrition, environmental and genetic factors. As the exposure to early influences can be separated from neurodevelopmental outcomes by many months or years, MRI markers can serve as an important intermediate outcome in multivariate analyses of neurodevelopmental determinants. Key to the success of such work are recent advances in data science as well as the growth of relevant data resources. Multimodal MRI assessment of neurodevelopment can be supplemented with other biomarkers of neurodevelopment such as electroencephalograms, magnetoencephalogram, and non-imaging biomarkers. This review focuses on how maternal nutrition impacts infant brain development, with three purposes: (1) to summarize the current knowledge about how nutrition in stages of pregnancy and breastfeeding impact infant brain development; (2) to discuss multimodal MRI and other measures of early neurodevelopment; and (3) to discuss potential opportunities for data science and artificial intelligence to advance precision nutrition. We hope this review can facilitate the collaborative march toward precision nutrition during pregnancy and the first year of life.

Reevaluation of Serum Arylesterase Activity in Neurodevelopmental Disorders

Organophosphate compounds (OPs) interfere with neurodevelopment and are neurotoxic for humans and animals. They are first biotransformed to the more toxic oxon form, and then hydrolyzed to specific metabolites by the enzyme paraoxonase/arylesterase, encoded by the gene PON1 located on human chr. 7q21.3. In autism spectrum disorder (ASD) and in attention-deficit/hyperactivity disorder (ADHD), a correlation between OP exposure and disease onset has been reported. In this case-control study, we aimed to replicate our previous work showing reduced levels of serum PON1 arylesterase activity in Italian and Caucasian-American ASD samples, and to extend our analysis to other neurodevelopmental disorders, namely ADHD and developmental language disorder (DLD), also known as specific language impairment (SLI). The arylesterase activity, measured using standard spectrophotometric methods, is significantly reduced in the ADHD, and not in the ASD sample compared with the controls. Our previous results seemingly stem from spuriously high arylesterase levels in the former control sample. Finally, genotyping SNPs rs705379 and rs662 using TDI-FP, a significant effect of rs705379 alleles on the serum arylesterase activity is observed in all of the subgroups tested, regardless of diagnosis, as well as a lack of association between PON1 gene polymorphisms and ASD/ADHD susceptibility in the Italian population. In summary, the serum arylesterase activity is reduced in children and adolescents with ADHD, and this reduction is not due to the functional PON1 gene variants assessed in this study. Based on previous literature, it may more likely reflect enhanced oxidative stress than specific genetic underpinnings.

Enduring language deficits in children of women with epilepsy and the potential role of intrauterine exposure to antiepileptic drugs

OBJECTIVE

Exposure to certain intrauterine antiepileptic drugs (AEDs) can negatively influence the language skills and intelligence of young children. It remains unanswered whether these deficits are transient or persist as children grow up. This study aims to evaluate the language function of children of women with epilepsy (CWE) aged 9-13 years in comparison with their peers, and its relationship with intrauterine AED exposure.

METHODS

We included 191 CWE in our study from the Kerala Registry of Epilepsy and Pregnancy. Children in the same age group (n = 144) and without maternal epilepsy or antenatal AED exposure served as controls. We used Clinical Examination for Language Function version IV to assess language in both groups. Relevant data related to maternal epilepsy and AED use were obtained from the registry records.

RESULTS

The average Core Language Scaled Score (CLSS) was significantly lower in CWE as compared to controls (83.19 vs 90.18, P = .001). Similarly, the mean scaled scores in other language parameters were also significantly lower in CWE. In the multivariate analysis, compared to control children, the average CLSS in CWE was 4.5 units lower (95% confidence interval [CI] = -8.8 to -0.2, P = .04) with AED monotherapy exposure and 7.3 units lower with exposure to AED polytherapy (95% CI = -13.8 to -0.8, P = .03). Intrauterine exposure to phenobarbitone (n = 61) and valproate (n = 55) as either monotherapy or polytherapy showed a negative effect on CLSS in CWE as compared to control children. However, carbamazepine (n = 75) and phenytoin (n = 37) use was not associated with significant variation of CLSS. In head-to-head comparisons between AED monotherapies in CWE, phenobarbitone showed a negative effect on CLSS (-14.7, 95% CI = -23.1 to -6.4, P = .001) as compared to carbamazepine.

SIGNIFICANCE

Intrauterine exposure to phenobarbitone and valproate impairs language development in CWE, with effects persisting into the second decade.

Effects of early and recent mercury and lead exposure on the neurodevelopment of children with elevated mercury and/or developmental delays during lactation: A follow-up study

This follow-up study of 82 children investigated the potential impact of early and recent exposure to mercury and lead on their neurodevelopmental performance at 5-8 years of age (2017-2018). Early exposure of these children to mercury, methylmercury, and lead was assessed during lactation at 3-12 months old, as well as their mother's exposure using measurements from a cross-sectional study (2011-2013). Only infants who failed to pass the neurodevelopment screening tools and/or had elevated mercury were included in this study. Urine and hair were sampled during the follow-up study to assess the children's recent exposure to mercury, methylmercury, and lead. Their cognitive performance and visual-motor integration were also measured using the Test of Non-Verbal Intelligence (TONI) and the Beery-Visual-Motor Integration (Beery VMI), respectively. The association between alterations in urinary porphyrins excretion and exposure to metals was analyzed and their influence on the children's neurodevelopment was explored. Linear regression models revealed a significant negative association between the infants' mercury exposure during lactation and the TONI Quotient (β = -0.298, 95%CI = -4.677, -0.414) and Beery VMI Age Equivalent scores at age 5-8 (β = -0.437, 95%CI = -6.383, -1.844). The mothers' blood methylmercury was inversely and significantly associated with their children's TONI Quotient (β = -0.231, 95%CI = -8.184, -0.331). In contrast, the children's Beery VMI Age Equivalent scores were positively and significantly associated with the hair methylmercury of the mothers (β = 0.214, 95%CI = 0.088, 3.899) and their infants (β = 0.256, 95%CI = 0.396, 4.488). These relationships suggest the presence of negative confounding that we did not take into account. Unlike mercury, there was some evidence that lead in breast milk had an inverse relationship with the children's visual-motor coordination skills. Our study did not show a clear association between children's recent exposure to metals and neurodevelopment. However, a significant inverse association was observed between the TONI Quotient and the interaction of hair methylmercury × ∑porphyrins (ß = -0.224, 95%CI = -0.86, -0.049), implying that porphyrins are a sensitive measure of low body-mercury burden. Although lead induced higher ∑porphyrins excretion in urine (β = 0.347, 95%CI = 0.107, 0.525), their interaction did not influence children's neurodevelopmental scores. The interactions between metals and porphyrins might provide insights into their potential contributory role in the pathogenesis associated with neurological disorders or other diseases. Despite the small sample size of the present study, its findings about the association between toxic metal exposure and the high risk of poor neurodevelopmental performance are worrying, particularly at an early age, and additional research is needed using larger sample sizes.

A framework for assessing the impact of chemical exposures on neurodevelopment in ECHO: Opportunities and challenges

The Environmental influences on Child Health Outcomes (ECHO) Program is a research initiative funded by the National Institutes of Health that capitalizes on existing cohort studies to investigate the impact of early life environmental factors on child health and development from infancy through adolescence. In the initial stage of the program, extant data from 70 existing cohort studies are being uploaded to a database that will be publicly available to researchers. This new database will represent an unprecedented opportunity for researchers to combine data across existing cohorts to address associations between prenatal chemical exposures and child neurodevelopment. Data elements collected by ECHO cohorts were determined via a series of surveys administered by the ECHO Data Analysis Center. The most common chemical classes quantified in multiple cohorts include organophosphate pesticides, polychlorinated biphenyls, polybrominated diphenyl ethers, environmental phenols (including bisphenol A), phthalates, and metals. For each of these chemicals, at least four ECHO cohorts also collected behavioral data during infancy/early childhood using the Child Behavior Checklist. For these chemicals and this neurodevelopmental assessment (as an example), existing data from multiple ECHO cohorts could be pooled to address research questions requiring larger sample sizes than previously available. In addition to summarizing the data that will be available, the article also describes some of the challenges inherent in combining existing data across cohorts, as well as the gaps that could be filled by the additional data collection in the ECHO Program going forward.

Biomonitoring of populations in Western New York at risk for exposure to Great Lakes contaminants

The New York State Department of Health conducted the Healthy Fishing Communities Program in collaboration with the Agency for Toxic Substances and Disease Registry to assess human exposure to contaminants common to Lake Ontario, Lake Erie and surrounding rivers and waterways among populations in western New York State who eat locally caught fish. The program enrolled licensed anglers and Burmese refugees and immigrants, living near four designated Great Lakes Areas of Concern: Buffalo River, Niagara River, Eighteenmile Creek, and the Rochester Embayment. These target populations were sampled and enrolled independently into the program between February and October of 2013. A core set of contaminants were measured in blood and urine of 409 licensed anglers and 206 Burmese refugees and immigrants which included lead, cadmium, mercury, PCBs, PBDEs, organochlorine pesticides (hexachlorobenzene, mirex, DDT, DDE, and chlordane and its metabolites oxychlordane and trans-Nonachlor), and PFOS and PFOA. Biomonitoring results showed that both groups had higher geometric means for blood lead, total blood mercury, and serum PFOS compared to the 2013-2014 NHANES reference levels. The Burmese refugee group also showed higher geometric means for creatinine-adjusted urine mercury and lipid-adjusted serum DDE compared to national levels. Licensed angler participants reported eating a median of 16 locally caught fish meals in the past year. Burmese participants consumed local fish throughout the year, and most frequently in the summer (median 39 fish meals or 3 times a week). The study results provide valuable information on populations at high risk of exposure to contaminants in the Great Lakes Basin of western New York. The results provide the foundation for developing and implementing public health actions to reduce potential exposures to Great Lakes pollutants.

Temporal trends of legacy and emerging persistent organic pollutants in inuit preschoolers from Northern Quebec (Canada)

In this study, we report the temporal trends of persistent organic pollutants (POPs) in 181 preschool Inuit children from Nunavik and the influence of confounding factors on blood contaminant levels. From 2006 to 2010, no significant trends were detected in Σpolychlorinated biphenyls (ΣPCBs), Σorganochlorine pesticides (ΣOPs), Σtoxaphene, and Σper- and polyfluoroalkyl substances (ΣPFASs). On the contrary, significant downward trends ranging from 9.3% to 14.3% per year were found for polybrominated diphenyl ethers (PBDEs). Breastfeeding was significantly associated with increased levels of POPs. Age was positively and significantly related to ΣPCBs, ΣOPs and Σtoxaphene. Compared with girls, boys had significantly higher concentrations of ΣPBDEs, but lower concentrations of ΣPFASs. Weight-for-height or body mass index z-scores were negatively and significantly related to ΣPCBs and ΣOPs. Passive smoking was positively and significantly associated with ΣOPs and Σtoxaphene. In conclusion, continued efforts to reduce contaminant exposure are needed to protect children's health and development.

Assessing lead-contaminated drinking water in a large academic institution: a case study

Drinking water is an important source of lead exposure, and definitively characterizing the sources of lead in drinking water, particularly in large institutional settings, can be time-consuming and costly. This study examined lead concentrations in drinking water at a large university, focusing on variability in first-draw samples and variability with dispensed volume. Over 350 sources were sampled twice by independent groups, and while 78% of these samples were within 2.5 μg/L, almost 10% differed by >10 μg/L. In both sampling events, approximately 50% of sources had lead concentrations >1 μg/L, 6% were >15 μg/L, and 30% were between 1 and 15 μg/L. The highest lead concentration detected was 400 μg/L, with five sources >100 μg/L. Nine sources were sampled more intensively and six had first-draw sample ranges >5 μg/L. Lead concentration versus dispensed volume profiles indicated that while most sources had decreasing lead concentrations after the first draw, others had maximum lead concentrations at higher dispensed volumes. The variability observed suggests that assessments using only one or two samples per source may not identify all sources with elevated lead concentrations, and management strategies should account for this possibility.

Environmental exposure to low-level lead (Pb) co-occurring with other neurotoxicants in early life and neurodevelopment of children

Lead (Pb) is a worldwide environmental contaminant that even at low levels influences brain development and affects neurobehavior later in life; nevertheless it is only a small fraction of the neurotoxicant (NT) exposome. Exposure to environmental Pb concurrent with other NT substances is often the norm, but their joint effects are challenging to study during early life. The aim of this review is to integrate studies of Pb-containing NT mixtures during the early life and neurodevelopment outcomes of children. The Pb-containing NT mixtures that have been most studied involve other metals (Mn, Al, Hg, Cd), metalloids (As), halogen (F), and organo-halogen pollutants. Co-occurring Pb-associated exposures during pregnancy and lactation depend on the environmental sources and the metabolism and half-life of the specific NT contaminant; but offspring neurobehavioral outcomes are also influenced by social stressors. Nevertheless, Pb-associated effects from prenatal exposure portend a continued burden on measurable neurodevelopment; they thus favor increased neurological health issues, decrements in neurobehavioral tests and reductions in the quality of life. Neurobehavioral test outcomes measured in the first 1000 days showed Pb-associated negative outcomes were frequently noticed in infants (<6 months). In older (preschool and school) children studies showed more variations in NT mixtures, children's age, and sensitivity and/or specificity of neurobehavioral tests; these variations and choice of statistical model (individual NT stressor or collective effect of mixture) may explain inconsistencies. Multiple exposures to NT mixtures in children diagnosed with 'autism spectrum disorders' (ASD) and 'attention deficit and hyperactivity disorders' (ADHD), strongly suggest a Pb-associated effect. Mixture potency (number or associated NT components and respective concentrations) and time (duration and developmental stage) of exposure often showed a measurable impact on neurodevelopment; however, net effects, reversibility and/or predictability of delays are insufficiently studied and need urgent attention. Nevertheless, neurodevelopment delays can be prevented and/or attenuated if public health policies are implemented to protect the unborn and the young child.

Benefits of cooperation among large-scale cohort studies and human biomonitoring projects in environmental health research: An exercise in blood lead analysis of the Environment and Child Health International Birth Cohort Group

A number of prospective cohort studies are ongoing worldwide to investigate the impact of foetal and neonatal exposures to chemical substances on child health. To assess multiple exposure (mixture) effects and low prevalence health outcomes it is useful to pool data from several studies and conduct mega-data-analysis. To discuss a path towards data harmonization, representatives from several large-scale birth cohort studies and a biomonitoring programme formed a collaborative group, the Environment and Child Health International Birth Cohort Group (ECHIBCG). In this study, an intra-laboratory trial was performed to harmonize existing blood lead measurements within the groups' studies. Then, decentralized analyses were conducted in individual countries' laboratories to evaluate blood lead levels (BLL) in each study. The measurements of pooled BLL samples in French, German and three Japanese laboratories resulted in an overall mean blood lead concentration of 8.66 μg l-1 (95% confidence interval: 8.59-8.72 μg l-1) with 3.0% relative standard deviation. Except for China's samples, BLL from each study were comparable with mean concentrations below or close to 10 μg l-1. The decentralized multivariate analyses revealed that all models had coefficients of determination below 0.1. Determinants of BLL were current smoking, age >35 years and overweight or obese status. The three variables were associated with an increase in BLL in each of the five studies, most strongly in France by almost 80% and the weakest effect being in Norway with only 15%; for Japan, with the far largest sample (~18,000), the difference was 36%. This study successfully demonstrated that the laboratory analytical methods were sufficiently similar to allow direct comparison of data and showed that it is possible to harmonize the epidemiological data for joint analysis. This exercise showed the challenges in decentralized data analyses and reinforces the need for data harmonization among studies.

Exposure profile of mercury, lead, cadmium, arsenic, antimony, copper, selenium and zinc in maternal blood, cord blood and placenta: the Tohoku Study of Child Development in Japan

BACKGROUND

The effects of prenatal exposure to toxic elements on birth outcomes and child development have been an area of concern. This study aimed to assess the profile of prenatal exposure to toxic elements, arsenic (As), bismuth (Bi), cadmium (Cd), mercury (total mercury (THg), methylmercury (MHg), inorganic mercury (IHg)), lead (Pb), antimony (Sb) and tin (Sn), and essential trace elements, copper (Cu), selenium (Se) and zinc (Zn), using the maternal blood, cord blood and placenta in the Tohoku Study of Child Development of Japan (N = 594-650).

METHODS

Inductively coupled plasma mass spectrometry was used to determine the concentrations of these elements (except mercury). Levels of THg and MeHg were measured using cold vapour atomic absorption spectrophotometry and a gas chromatograph-electron capture detector, respectively.

RESULTS

Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the maternal blood were 4.06 (2.68-6.81), 1.18 (0.74-1.79), 10.8 (8.65-13.5), 0.2 (0.06-0.40) and 0.2 (0.1-0.38) ng mL^-1 and 5.42 (3.89-7.59) ng g^-1, respectively. Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the cord blood were 3.68 (2.58-5.25), 0.53 (0.10-1.25), 9.89 (8.02-12.5), 0.39 (0.06-0.92) and 0.2 (0.2-0.38) ng mL^-1 and 9.96 (7.05-13.8) ng g^-1, respectively.

CONCLUSIONS

THg and Sb levels in the cord blood were twofold higher than those in the maternal blood. Cord blood to maternal blood ratios for As, Cd and Sb widely varied between individuals. To understand the effects of prenatal exposure, further research regarding the variations of placental transfer of elements is necessary.

Biomonitoring programs in Michigan, Minnesota and New York to assess human exposure to Great Lakes contaminants

Over the past century, industrialization and urban practices have resulted in the contamination of the Great Lakes ecosystem-the world's largest surface freshwater system-that provides drinking water and recreation to more than 40 million residents. In 2010, the Great Lakes Restoration Initiative was launched to accelerate efforts to protect and restore the Great Lakes and surrounding areas. Funded by GLRI, the Agency for Toxic Substances and Disease Registry initiated the Biomonitoring of Great Lakes Populations (BGLP) program. The objective of the program is to assess human exposure to legacy and emerging contaminants in the Great Lakes by measuring the body burden of contaminants in potentially susceptible populations. The BGLP program consists of a series of cross-sectional studies carried out collaboratively with states that are funded through ATSDR. The first BGLP Program (BGLP-I) began in 2010 and was completed in September 2015 through cooperative agreements with state health departments in Michigan, Minnesota, and New York. The three state programs targeted susceptible adult populations living in designated areas of contamination. Contaminants measured in all populations include mercury, lead, mirex, hexachlorobenzene, dichlorodiphenyltrichloroethane, and selected polychlorinated biphenyl congeners. In addition, some chemicals of emerging concern, such as per- and polyfluoroalkyl substances, were measured in several populations. The biomonitoring results helped guide public health actions to mitigate chemical exposures in these vulnerable Great Lakes populations. We provide an overview of the BGLP-I program's study populations, designs, and general methods. This overview provides a lead-in for subsequent manuscripts that present human biomonitoring data for legacy and emerging contaminants in culturally diverse susceptible populations-i.e., shoreline anglers, sport anglers, American Indians, and Burmese immigrants-residing in seven areas of concern.

Fetal toxicology

Toxic chemicals, either from natural sources or man-made, are ubiquitous in our environment. Many of the synthetic chemicals make life more comfortable and therefore production continues to grow. Simultaneously with the increase in production, an increase in neurodevelopmental disorders has been observed. Some chemicals are not biodegradable or have a very long half-life time and, despite the fact that production of a number of those chemicals has been severely reduced, they are still ubiquitous in the environment. Fetal exposure to toxic chemicals is dependent on maternal exposure to those chemicals and the developing stage of the fetus. Human evidence from epidemiologic studies is described with regard to the effect of prenatal exposure to various groups of neurotoxicants (alcohol, particulate fine matter, metals, and endocrine disrupting chemicals) on neurobehavior development. Data indicate that prenatal exposure to alcohol, polycyclic aromatic hydrocarbons, lead, methylmercury (MeHg), organophosphate pesticides (OPPs), and polychlorinated biphenyl ethers (PBDEs) impair cognitive development, whereas exposure to alcohol, MeHg, organochlorine pesticides and OPPs, polychlorinated biphenyls, PBDEs, and bisphenol A increases the risk of developing either attention deficit/hyperactivity and/or autism spectrum disorders. Psychomotor development appears to be less affected. However, data are not conclusive, which may depend on the assessment of exposure and the exposure level, among other factors.

Multiple low-level exposures: Hg interactions with co-occurring neurotoxic substances in early life

All chemical forms of Hg can affect neurodevelopment; however, low levels of organic Hg (methylmercury-MeHg and ethylmercury-EtHg in Thimerosal-containing vaccines, hereafter 'TCV') exposures during early life (pregnancy and lactation) co-occur with other environmental neurotoxic substances. These neurotoxicants may act in parallel, synergistically, or antagonistically to Hg. Nevertheless, the risks of neurotoxicity associated with multiple neuro-toxicants depend on type, time, combinations of exposure, and environmental and/or genetic-associated factors. Neurological developmental disorders, delays in cognition and behavioral outcomes associated with multiple exposures (which include Hg) may show transient or lasting outcomes depending on constitutional and/or environmental factors that can interact to neutralize, aggravate or attenuate these effects; often these studies are challenging to interpret. During pregnancy and lactation, fish-MeHg exposure is frequently confounded with the opposing effects of neuroactive nutrients (in fish) that lead to positive, negative, or no effects on neurobehavioral tests. In infancy, exposures to acute binary mixtures (TCV- EtHg and Al-adjuvants in infant immunizations) are associated with increased risks of tics and other developmental disorders. Despite the certitude that promulgates single environmental neurotoxicants, empirical comparisons of combined exposures indicate that Hg-related outcome is uneven. Hg in combination with other neurotoxic mixtures may elevate risks of neurotoxicity, but these risks arise in circumstances that are not yet predictable. Therefore, to achieve the goals of the Minamata treaty and to safeguard the health of children, low levels of mercury exposure (in any chemical form) needs to be further reduced whether the source is environmental (air- and food-borne) or iatrogenic (pediatric TCVs).

Educating speech-language pathologists working in early intervention on environmental health

BACKGROUND

The goals of this study were (1) to determine early intervention (EI) Speech-Language Pathologists' (SLPs) level of training and knowledge on environmental toxicants and their effect on infant and child development; and (2) to examine the effectiveness of a continuing education (CE) event designed to enhance the knowledge of EI SLPs on environmental toxicants and their effects on child development.

METHODS

A survey was launched via Qualtrics and posted on the American Speech-Language Hearing Association's Early Intervention Community page to assess environmental health knowledge of SLPs. Results from this survey were used to create an environmental health CE event targeted towards EI SLPs. Attendees were given a pre- and post-test to assess the effectiveness of our program.

RESULTS

One hundred and fifty-eight participants completed the online survey and a majority (61%, n = 97) of participants reported some level of dissatisfaction with their previous training in regards to environmental exposures. Fifty-six percent (n = 89) of the participants also reported feeling unprepared to be a health advocate regarding environmental exposure concerns within their community. Forty-eight people (26 SLPs and 22 SLP master's students) attended the CE event. Paired t-tests revealed significant improvements from the pre- to the post- test results among all attendees.

CONCLUSIONS

These findings suggest that SLPs who work in EI feel undertrained and unprepared to advocate for environmental health to the families they serve. This study reveals that CE is one way by which to increase the knowledge base of SLPs on environmental health.

Endocrine active metals, prenatal stress and enhanced neurobehavioral disruption

Metals, including lead (Pb), methylmercury (MeHg) and arsenic (As), are long-known developmental neurotoxicants. More recently, environmental context has been recognized to modulate metals toxicity, including nutritional state and stress exposure. Modulation of metal toxicity by stress exposure can occur through shared targeting of endocrine systems, such as the hypothalamic-pituitary-adrenal axis (HPA). Our previous rodent research has identified that prenatal stress (PS) modulates neurotoxicity of two endocrine active metals (EAMs), Pb and MeHg, by altering HPA and CNS systems disrupting behavior. Here, we review this research and further test the hypothesis that prenatal stress modulates metals neurotoxicity by expanding to test the effect of developmental As ± PS exposure. Serum corticosterone and behavior was assessed in offspring of dams exposed to As ± PS. PS increased female offspring serum corticosterone at birth, while developmental As exposure decreased adult serum corticosterone in both sexes. As + PS induced reductions in locomotor activity in females and reduced response rates on a Fixed Interval schedule of reinforcement in males, with the latter suggesting unique learning deficits only in the combined exposure. As-exposed males showed increased time in the open arms of an elevated plus maze and decreased novel object recognition whereas females did not. These data further confirm the hypothesis that combined exposure to chemical (EAMs) and non-chemical (PS) stressors results in enhanced neurobehavioral toxicity. Given that humans are exposed to multiple environmental risk factors that alter endocrine function in development, such models are critical for risk assessment and public health protection, particularly for children.

Blood lead levels and longitudinal language outcomes in children from 4 to 12 years

OBJECTIVES

In this study, the authors aimed to examine the association of a range of blood lead levels on language skills assessed at 4, 6, 10 and 12 years of age using a prospective longitudinal design controlling for potential confounding variables including maternal vocabulary, caregiver's psychological distress and symptomatology, child's race and prenatal drug exposure.

METHODS

The participants (N = 278) were a subsample of a large longitudinal study that examined the association of prenatal drug exposure on children who were followed prospectively from birth and assessed for receptive and expressive language skills at 4, 6, 10 and 12 years of age. Blood lead levels were determined at 4-years of age by atomic absorption spectrometry. A mixed model approach with restricted maximum likelihood procedures was used to assess the association of lead on language outcomes.

RESULTS

Longitudinal mixed model analyses suggested a negative effect of lead exposure on both receptive and expressive language, with the adverse outcomes of lead exposure appearing to become more prominent at 10 and 12 years. Higher caregiver vocabulary was positively associated with child's language scores whereas caregiver psychological distress appeared to negatively affect language scores. Prenatal drug exposure was not related to the effects of lead on language skills.

CONCLUSIONS

These findings suggest that elevated blood lead levels occurring early in life may be associated with poorer language skills at older ages. A language rich environment may minimize the negative influence of early lead exposure on language skills, with psychological distress seemingly exacerbating the negative outcome.

Low-Level Prenatal Toxin Exposures and Breastfeeding Duration: A Prospective Cohort Study

Introduction Maternal exposure to tobacco smoke is associated with shortened breastfeeding duration, but few studies have examined the effects on breastfeeding outcomes of low level exposures to other toxic chemicals. Moreover, it is unclear if passive smoking is associated with duration of breastfeeding. Our objective was therefore to examine the effect of low-level prenatal exposures to common environmental toxins (tobacco smoke, lead, and phthalates) on breastfeeding exclusivity and duration. Methods We conducted an analysis of data from the Health Outcomes and Measures of the Environment (HOME) Study. Serum and urine samples were collected at approximately 16 and 26 weeks gestation and at delivery from 373 women; 302 breastfed their infants. Maternal infant feeding interviews were conducted a maximum of eight times through 30 months postpartum. The main predictor variables for this study were gestational exposures to tobacco smoke (measured by serum cotinine), lead, and phthalates. Passive smoke exposure was defined as cotinine levels of 0.015-3.0 μg/mL. Primary outcomes were duration of any and exclusive breastfeeding. Results Serum cotinine concentrations were negatively associated with the duration of any breastfeeding (29.9 weeks unexposed vs. 24.9 weeks with passive exposure, p = 0.04; and 22.4 weeks with active exposure, p = 0.12; p = 0.03 for linear trend), but not duration of exclusive breastfeeding. Prenatal levels of blood lead and urinary phthalate metabolites were not significantly associated with duration of any or exclusive breastfeeding. Conclusions Passive exposure to tobacco smoke during pregnancy was associated with shortened duration of any breastfeeding.

Childhood pesticide poisoning in Zhejiang, China: a retrospective analysis from 2006 to 2015

Background

Pesticide poisoning in children has been a serious public health issue around the world, especially in the developing countries where agriculture is still one of the largest economic sectors. The purpose of this study was to analyze epidemiological characteristics of acute pesticide poisoning in children from Zhejiang province, China.

Methods

The pesticide poisoning cases for children were retrieved from Occupational Disease Surveillance and Reporting System, Zhejiang Provincial Center for Disease Control and Prevention, China. The incident cases, deaths, and fatality rate of child pesticide poisoning from 2006 through 2015 were calculated.

Results

During the study period, totally 2952 children were poisoned by pesticides, with 66 deaths, resulting in a fatality rate of 2.24%. Among them, there were 1607 male cases with 28 deaths, and 1345 female cases with 38 deaths. Most of the cases occurred in preschool children (1349) and adolescent age group (1269). Organophosphate and carbamate insecticides were the cause of most poisonings (1130), leading to 34 deaths. The highest fatality rate (3.13%) was due to poisoning by herbicides and fungicides, causing 14 deaths out of 448 cases. Poisoning occurred mostly in rural areas (78%). And most pesticide poisoning occurred in the summer (896) and fall (811), while fewest poisoning cases in the winter (483) but with the highest fatality rate (3.52%).

Conclusions

This study shows that pesticide poisoning of children is a major health problem in Zhejiang, suggesting preventive strategies should be conducted to control childhood pesticide poisoning.

Prenatal PBDE and PCB Exposures and Reading, Cognition, and Externalizing Behavior in Children

BACKGROUND

Prenatal polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) exposures may influence children's neurodevelopment.

OBJECTIVE

We examined the association of prenatal PBDE and PCB exposures with children's reading skills at ages 5 and 8 years, Full-Scale Intelligence Quotient (FSIQ), and externalizing behavior problems at age 8 years.

METHODS

From 239 mother-child pairs recruited (2003-2006) in Cincinnati, Ohio, we measured maternal serum PBDE and PCB concentrations, assessed child's reading skills using the Woodcock-Johnson Tests of Achievement III (WJ-III) at age 5 years and the Wide Range Achievement Test-4 (WRAT-4) at age 8 years, tested FSIQ using the Wechsler Intelligence Scale for Children-IV (WISC-IV), and externalizing behavior problems using the Behavioral Assessment System for Children-2 (BASC-2) at age 8 years. We used multiple linear regression to examine the association of prenatal PBDE and PCB concentrations and reading, FSIQ, and externalizing behavior problems after adjusting for covariates.

RESULTS

An increase of Sum4PBDEs (BDE-47, BDE-99, BDE-100, and BDE-153) by 10 times was not significantly associated with reading scores at age 5 years at the p = 0.05 level but was inversely associated with Reading Composite scores (β: -6.2, 95% CI: -11.7, -0.6) and FSIQ (β: -5.3, 95% CI: -10.6, -0.02) at age 8 years; it was positively associated with the score for externalizing behavior problems (β: 3.5, 95% CI: -0.1, 7.2) at age 8 years. Prenatal Sum4PCBs (PCB-118, -153, -138-158, and -180) was not significantly associated with a child's reading skills, FSIQ, and externalizing behavior problems.

CONCLUSION

Prenatal PBDE concentration was inversely associated with reading skills and FSIQ and positively associated with externalizing behavior problems at age 8 years. No significant associations were found in prenatal PCB concentration.

Association of blood heavy metals with developmental delays and health status in children

The aim of this study was to evaluate the association of blood lead, mercury, and cadmium concentrations with developmental delays and to explore the association of these concentrations with the health status of children. This study recruited 89 children with developmental delays and 89 age- and sex-matched children with typical development. Their health status was evaluated using the Pediatric Quality of Life (PedsQL) Inventory for health-related quality of life (HRQOL) and the Pediatric Outcomes Data Collection Instrument for function. Family function was also evaluated. Blood lead, mercury, and cadmium concentrations were measured using inductively coupled mass spectrometry. The children with developmental delays had a considerably poorer HRQOL, lower functional performance and family function, and a higher blood lead concentration than those with typical development. The blood lead concentration had a significantly positive association with developmental delays [odds ratio (OR) = 1.54, p < 0.01] in a dose-response manner, and it negatively correlated with PedsQL scores (regression coefficient: −0. 47 to −0.53, p < 0.05) in all the children studied. The higher blood cadmium concentration showed a significantly positive association with developmental delays (OR = 2.24, for >1.0 μg/L vs. <0.6 μg/L, p < 0.05). The blood mercury concentration was not associated with developmental delays and health status.

Epigenetic impacts of endocrine disruptors in the brain

The acquisition of reproductive competence is organized and activated by steroid hormones acting upon the hypothalamus during critical windows of development. This review describes the potential role of epigenetic processes, particularly DNA methylation, in the regulation of sexual differentiation of the hypothalamus by hormones. We examine disruption of these processes by endocrine-disrupting chemicals (EDCs) in an age-, sex-, and region-specific manner, focusing on how perinatal EDCs act through epigenetic mechanisms to reprogram DNA methylation and sex steroid hormone receptor expression throughout life. These receptors are necessary for brain sexual differentiation and their altered expression may underlie disrupted reproductive physiology and behavior. Finally, we review the literature on histone modifications and non-coding RNA involvement in brain sexual differentiation and their perturbation by EDCs. By putting these data into a sex and developmental context we conclude that perinatal EDC exposure alters the developmental trajectory of reproductive neuroendocrine systems in a sex-specific manner.

Chlorpyrifos exposure affects fgf8, sox9, and bmp4 expression required for cranial neural crest morphogenesis and chondrogenesis in Xenopus laevis embryos

Chlorpyrifos (CPF) is an organophosphate insecticide used primarily to control foliage and soil-borne insect pests on a variety of food and feed crops. In mammals, maternal exposure to CPF has been reported to induce dose-related abnormalities such as slower brain growth and cerebral cortex thinning. In lower vertebrates, for example, fish and amphibians, teratogenic activity of this compound is correlated with several anatomical alterations. Little is known about the effects of CPF on mRNA expression of genes involved in early development of the anatomical structures appearing abnormal in embryos. This study investigated the effects of exposure to different CPF concentrations (10, 15 and 20 mg/L) on Xenopus laevis embryos from stage 4/8 to stage 46. Some of the morphological changes we detected in CPF-exposed embryos included cranial neural crest cell (NCC)-derived structures. For this reason, we analyzed the expression of select genes involved in hindbrain patterning (egr2), cranial neural crest chondrogenesis, and craniofacial development (fgf8, bmp4, sox9, hoxa2 and hoxb2). We found that CPF exposure induced a reduction in transcription of all the genes involved in NCC-dependent chondrogenesis, with largest reductions in fgf8 and sox9; whereas, in hindbrain, we did not find any alterations in egr2 expression. Changes in the expression of fgf8, bmp4, and sox9, which are master regulators of several developmental pathways, have important implications. If these changes are confirmed to belong to a general pattern of alterations in vertebrates prenatally exposed to OP, they might be useful to assess damage during vertebrate embryo development. Environ. Mol. Mutagen. 57:589-604, 2016. © 2016 Wiley Periodicals, Inc.

The influence of maternal dietary exposure to dioxins and PCBs during pregnancy on ADHD symptoms and cognitive functions in Norwegian preschool children

BACKGROUND

Polychlorinated dibenzo-p-dioxins/dibenzofurans (dioxins) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) with potentially adverse impact on child neurodevelopment. Whether the potential detrimental effects of dioxins and PCBs on neurodevelopment are of specific or unspecific character is not clear.

OBJECTIVES

The purpose of the current study was to examine the influence of maternal dietary exposure to dioxins and PCBs on ADHD symptoms and cognitive functioning in preschoolers. We aimed to investigate a range of functions, in particular IQ, expressive language, and executive functions.

MATERIAL AND METHODS

This study includes n=1024 children enrolled in a longitudinal prospective study of ADHD (the ADHD Study), with participants recruited from The Norwegian Mother and Child Cohort Study (MoBa). Boys and girls aged 3.5years participated in extensive clinical assessments using well-validated tools; The Preschool Age Psychiatric Assessment interview (PAPA), Stanford-Binet 5th revision (SB-5), Child Development Inventory (CDI), and Behavior Rating Inventory of Executive Function, Preschool version (BRIEF-P). Maternal dietary exposure to dioxins and PCBs was estimated based on a validated food frequency questionnaire (FFQ) answered mid-pregnancy and a database of dioxin and PCB concentrations in Norwegian foods. Exposure to dioxins and dioxin-like PCBs (dl-compounds) was expressed in total toxic equivalents (TEQ), and PCB-153 was used as marker for non-dioxin-like PCBs (ndl-PCBs). Generalized linear and additive models adjusted for confounders were used to examine exposure-outcome associations.

RESULTS

Exposure to PCB-153 or dl-compound was not significantly associated with any of the outcome measures when analyses were performed for boys and girls together. After stratifying by sex, adjusted analyses indicated a small inverse association with language in girls. An increase in the exposure variables of 1 SD was associated with a reduction in language score of -0.2 [CI -0.4, -0.1] for PCB-153 and -0.2 [CI -0.5, -0.1] for dl-compounds in girls. For boys, exposure to PCB-153 or dl-compounds was not associated with language skills. The difference between sex-specific associations was not statistically significant (p-value=0.13). No sex-specific effects were observed for ADHD-symptoms, IQ scores, or executive functions.

CONCLUSIONS

We found no indications that variation in current low-level exposure to PCB-153 or dl-compounds in Norway is associated with variation ADHD-symptoms, verbal/non-verbal IQ, or executive functions including working memory in preschoolers. However, our findings indicated that maternal dietary exposure to PCB-153 or dl-compounds during pregnancy was significantly associated with poorer expressive language skills in preschool girls, although the sex-specific associations were not significantly different.

Maternal dietary exposure to dioxins and polychlorinated biphenyls (PCBs) is associated with language delay in 3year old Norwegian children

BACKGROUND

Prenatal exposure to dioxins and PCBs is potentially harmful to the developing fetus and may increase the risk of delayed or impaired neurodevelopment. Several studies have reported negative associations between prenatal exposure to these compounds and aspects of cognition related to language in early childhood.

OBJECTIVES

The aim was to examine the association between maternal low level dietary exposure to dioxins and PCB during pregnancy and language development in 3year old children in a large group of mother-child pairs participating in the Norwegian Mother and Child Cohort Study (MoBa).

METHODS

This study includes 44,092 children of women who were recruited to the Norwegian Mother and Child Cohort Study (MoBa) during the years 2002-2009. Maternal dietary exposure to dioxins and PCBs was estimated based on a validated food frequency questionnaire (FFQ) answered mid-pregnancy and a database of dioxin and PCB concentrations in Norwegian foods. Exposure to dioxins and dioxin-like PCBs (dl-compounds) was expressed in total toxic equivalents (TEQ), and PCB-153 was used as marker for non-dioxin-like PCBs (ndlPCBs). Children's language skills at age 3 were assessed by parental report including a Dale and Bishop grammar rating and questions about communication skills from the Ages and Stages Questionnaire (ASQ). Logistic regression models adjusted for confounders were used to examine the association between maternal dietary exposure to dl-compounds or PCB-153 and language development in children.

RESULTS

The maternal dietary exposure to dl-compounds and PCB-153 was generally low, and 98% of women had intakes of dl-compounds ≤14pg TEQ/kg bw/week, which is the tolerable weekly intake set by EU's Scientific Committee for Food (SCF). High maternal exposure (>14pg TEQ/kg bw/week of dl-compounds (median 2.6pg/kg bw/day, range 2-16) or >97.5-percentile intake of PCB-153 (median 11ng/kg bw/day, range 5-28) was associated with higher odds of incomplete grammar (in boys and girls, adjusted ORs 1.1 to 1.3) and severe language delay in girls, adjusted ORs 2.8 [95% CI 1.1, 7.1] for PCB-153 and 2.9 [95% CI 1.4, 5.9] for dl-compounds. Furthermore, high exposure to dl-compounds was associated with moderate language delay 1.4 [95% CI 1.0, 2.0] and lower communication score (ASQ), adjusted OR 1.4 [95% CI 1.1, 1.9] in girls.

CONCLUSIONS

The main findings of this study were: 1) Girls born to mothers who exceeded the tolerable weekly intake for dl-compounds or had a PCB-153 intake above the 97.5 percentile in early pregnancy may have increased risk of language delay at age 3years. 2) Negative associations with maternal exposure to dl-compounds or PCB-153 were observed for both boys and girls having incomplete grammar, which is a subtle reduction in language skills. This interesting finding should not be considered as deviant at this age.

"So we would all help pitch in:" The family literacy practices of low-income African American mothers of preschoolers

The development of emergent literacy skills are important for the development of later literacy competencies and affect school readiness. Quantitative researchers document race- and social class-based disparities in emergent literacy competence between low-income African American and middle-income White children. Some researchers suggest that deficits in parenting practices account for limited literacy skills among low-income African American children. A small body of qualitative research on low-income African American families finds that despite economic challenges, some African American families were actively engaged in promoting child literacy development. Using qualitative interviews that emphasize family strengths, we add to this small body of research to highlight positive family practices obscured in many quantitative analyses that concentrate on family shortcomings. Specifically, we examine in-home literacy practices and child literacy development with a sample of low-income African American mothers (families) of preschoolers. Key findings include identification of various literacy activities promoting child literacy development and inclusion of multiple family members assisting in literacy activities. These findings add to substantive discussions of emergent literacy and resilience. Insights from the qualitative interviews also provide culturally-sensitive recommendations to childhood educators and speech-language pathologists (SLP) who work with low-income African American families and children.

LEARNING OUTCOMES

Reader should recognize that (1) there is not a 'right' phenotype and therefore not a right form of environmental input and (2) that context matters (at both the level of the cell and the individual organism).