The impact of childhood lead exposure on adult personality: Evidence from the United States, Europe, and a large-scale natural experiment.

Childhood lead exposure has devastating lifelong consequences, as even low-level exposure stunts intelligence and leads to delinquent behavior. However, these consequences may be more extensive than previously thought because childhood lead exposure may adversely affect normal-range personality traits. Personality influences nearly every aspect of human functioning, from well-being to career earnings to longevity, so effects of lead exposure on personality would have far-reaching societal consequences. In a preregistered investigation, we tested this hypothesis by linking historic atmospheric lead data from 269 US counties and 37 European nations to personality questionnaire data from over 1.5 million people who grew up in these areas. Adjusting for age and socioeconomic status, US adults who grew up in counties with higher atmospheric lead levels had less adaptive personality profiles: they were less agreeable and conscientious and, among younger participants, more neurotic. Next, we utilized a natural experiment, the removal of leaded gasoline because of the 1970 Clean Air Act, to test whether lead exposure caused these personality differences. Participants born after atmospheric lead levels began to decline in their county had more mature, psychologically healthy adult personalities (higher agreeableness and conscientiousness and lower neuroticism), but these findings were not discriminable from pure cohort effects. Finally, we replicated associations in Europeans. European participants who spent their childhood in areas with more atmospheric lead were less agreeable and more neurotic in adulthood. Our findings suggest that further reduction of lead exposure is a critical public health issue.

Low-level developmental lead exposure does not predispose to adult alcohol self-administration, but does increase the risk of relapsing to alcohol seeking in mice: Contrasting role of GLT1 and xCT brain expression.

Lead (Pb) is a neurotoxic heavy metal pollutant. Despite the efforts to reduce Pb environmental exposure and to prevent Pb poisoning, exposure in human populations persists. Studies of adults with history of childhood lead exposure have consistently demonstrated cognitive impairments that have been associated with sustained glutamate signaling. Additionally, some clinical studies have also found correlations between Pb exposure and increased proclivity to drug addiction. Thus, here we sought to investigate if developmental Pb exposure can increase propensity to alcohol consumption and relapse using an alcohol self-administration paradigm. Because Pb exposure is associated with increased glutamatergic tone, we also studied the effects on the expression of synaptic and non-synaptic glutamate transporters in brain regions associated with drug addiction such as the nucleus accumbens (NAc), dorsomedial striatum (DMS), dorsolateral striatum (DLS), and medial prefrontal cortex (mPFC). We found that while developmental Pb exposure did not increase risk for alcohol self-administration, it did play a role in relapsing to alcohol. The effects were associated with differential expression of the glutamate transporter 1 (GLT1) and the glutamate/cystine antiporter (xCT). In the NAc and DLS the expression of GLT1 was found to be significantly reduced, while no changes were found in DMS or mPFC. Contrastingly, xCT was found to be upregulated in NAc but downregulated in DLS, with no changes in DMS or mPFC. Our data suggest that lead exposure is involved in relapse to alcohol seeking, an effect that could be associated with downregulation of GLT1 and xCT in the DLS.

Study on Effects and Mechanism of Lead and High-Fat Diet on Cognitive Function and Central Nervous System in Mice.

OBJECTIVE: We sought to investigate the effects and mechanism of lead and a high-fat diet on cognitive function and the central nervous system in mice. METHODS: Eighty-four healthy male mice were randomly divided into a control group (n = 21) (fed with common diet and free drinking), a lead exposure group (n = 21) (fed with common diet and 300 mg/L lead acetate solution), a high-fat group (n = 21) (fed with high-fat diet and free drinking), and a lead + high-fat group (n = 21) (fed with high-fat diet and 300 mg/L lead acetate solution). In 10 weeks after lead exposure, the mice of all groups were tested for the cognition, learning and memory abilities, body weight, serum triglyceride (TG), low-density lipoprotein, and high-density lipoprotein, as well as for the contents of lead, interleukin 6 (IL-6), interleukin 17 (IL-17), interferon γ, advanced glycation end products (AGEs), glutathione S-transferase (GSH-ST), and hydrogen peroxide in the brain tissues. RESULTS: Compared with the control group and the lead-exposed group, the body weights of mice in the high-fat group and the lead + high-fat group increased significantly from the sixth week of the experiment, of which the difference was statistically significant (P < 0.05). Compared with the control group and the high-fat group, the lead content in brain tissue of the lead exposure group and the lead + high-fat group increased significantly, of which the difference was statistically significant (P < 0.05). Compared with the control group, the escape latent period, triglyceride, low-density lipoprotein, IL-6, IL-17, interferon γ, and AGEs of the remaining 3 groups increased significantly, but the recognition index, passing platform times, high-density lipoprotein, and GSH-ST significantly decreased (P < 0.05); the second and third escape latent periods, IL-6, IL-17, and AGEs of lead + high-fat group, were obviously higher than the remaining 3 groups, but the passing platform times were obviously lower than the remaining 3 groups, of which the difference was statistically significant. The content of hydrogen peroxide in brain tissues had no difference among groups (P > 0.05). CONCLUSIONS: The lead and high-fat diet resulted in lipid metabolism disorders and impaired the cognitive function and central nervous system by promoting the secretion of inflammatory factors in glial cells, inducing the inflammatory reaction of brain tissue, inhibiting GSH-ST expression, and increasing AGEs content.

Chronic lead exposure decreases the expression of Huntingtin-associated protein 1 (HAP1) through Repressor element-1 silencing transcription (REST).

Chronic lead (Pb) exposure has been shown to reduce the expression of some synaptic proteins which are involved in vesicular trafficking and affect presynaptic neurotransmitter release. However, the precise mechanisms by Pb impairs neurotransmitter release are still not well defined. In the current study, we aimed to elucidate the changes of Huntingtin-associated protein 1 (HAP1) in Pb exposed rats and PC12 cells models and its molecular mechanism. Repressor element-1 silencing transcription (REST) modulates the expression of genes containing the repressor element 1 (RE-1) cis-regulatory DNA sequence. HAP1 promoter region contains a RE-1 binding motif. We also observed whether Pb exposure regulated the HAP1 transcription level through influencing the expression of REST. Mother rats were exposed to 0.5 and 2 g/L Pb acetate (PbAc) in drinking water from the first day of gestation until postnatal 21 days, then the offspring rats were continued to drink PbAc for 1 year, while the control groups received drinking water. PC12 cells were divided into 3 groups: 0 µM, 1 µM and 100 µM PbAc. The results revealed that Pb levels in blood and brain of Pb exposed groups were significantly higher than that of the control group. The ability of learning and memory in Pb exposed rats was decreased. Pb exposure reduced the expression of HAP1 and increased the REST expression. Silencing REST could reverse the decreasing of HAP1 in Pb exposed PC12 cells. Our findings raise a possibility that the decreasing of HAP1 expression by Pb exposure may affect neurotransmitter release and results in impairments in spatial learning and memory ability.

Lead exposure and child maltreatment as models for how to conceptualize early-in-life risk factors for violence.

Although rates of violent crime have been on the decline in the United States for the past two decades, young people-and particularly young men-continue to commit and fall victim to alarmingly high rates of violence. Effective prevention requires data on what the determinants of violence are and when in the life course they emerge. The goal of this review was to identify early-in-life risk factors for violence and to describe (a) who is most affected and (b) effect mechanisms. I focus on abuse and neglect and exposure to lead as risk factors for violence that disproportionately affect young children and that are likely to have causal effects on development. I conclude with future directions for research and intervention.

The role of the South African Medical Research Council in reducing lead exposure and preventing lead poisoning in South Africa.

Even at low levels in blood, lead has been associated with reduced IQ scores, behavioural problems, learning impediments, aggression and violent behaviour. Since the 1980s, the South African Medical Research Council (SAMRC) has been investigating the sources of exposure to lead in South Africa (SA), the groups at highest risk of lead poisoning and a selection of the myriad associated health and social consequences. SAMRC research evidence contributed to the phasng out of leaded petrol, restrictions on lead in paint and other interventions. Subsequently, childhood blood lead levels in SA declined significantly. More recent studies have revealed elevated risks of lead exposure in subsistence fishing and mining communities, users of arms and ammunition, those ingesting certain traditional medicines, and users of certain ceramicware and artisanal cooking pots. Lead-related cognitive damage costs the SA economy ~USD17.7 (ZAR261.3) billion annually, justifying further SAMRC investment in lead exposure research in the country.

Assessment of Behavioral Health Concerns in the Community Affected by the Flint Water Crisis - Michigan (USA) 2016.

OBJECTIVES: The Flint Community Resilience Group (Flint, Michigan USA) and the Centers for Disease Control and Prevention (CDC; Atlanta, Georgia USA) assessed behavioral health concerns among community members to determine the impact of lead contamination of the Flint, Michigan water supply. METHODS: A Community Assessment for Public Health Emergency Response (CASPER) was conducted from May 17 through May 19, 2016 using a multi-stage cluster sampling design to select households and individuals to interview. RESULTS: One-half of households felt overlooked by decision makers. The majority of households self-reported that at least one member experienced more behavioral health concerns than usual. The prevalence of negative quality of life indicators and financial concerns in Flint was higher than previously reported in the Michigan 2012 and 2014 Behavioral Risk Factor Surveillance System (BRFSS) survey. CONCLUSIONS: The following can be considered to guide recovery efforts in Flint: identifying additional resources for behavioral health interventions and conducting follow-up behavioral health assessments to evaluate changes in behavioral health concerns over time; considering the impact of household economic factors when implementing behavioral health interventions; and ensuring community involvement and engagement in recovery efforts to ease community stress and anxiety. FortenberryGZ, ReynoldsP, BurrerSL, Johnson-LawrenceV, WangA, SchnallA, PullinsP, KieszakS, BayleyegnT, WolkinA. Assessment of behavioral health concerns in the community affected by the Flint water crisis - Michigan (USA) 2016. Prehosp Disaster Med. 2018;33(3):256-265.

The effects of lead exposure on the expression of HMGB1 and HO-1 in rats and PC12 cells.

Lead (Pb) is an environmental neurotoxic metal. Chronic exposure to Pb causes deficits of learning and memory in children and spatial learning deficits in developing rats. In this study we investigated the effects of Pb exposure on the expression of HMGB1 and HO-1 in rats and PC12 cells. The animals were randomly divided to three groups: control group; low lead exposure group; high lead exposure group; PC12 cells were divided into 3 groups: 0 µM (control group), 1 µM and 100 µM Pb acetate. The results showed that Pb levels in blood and brain of Pb exposed groups were significantly higher than that of the control group (p < 0.05). The expression of HMGB1 and HO-1 were increased in Pb exposed groups than that of the control group (p < 0.05). Moreover, we found that the up-regulation of HO-1 in Pb exposure environment inhibited the expression of HMGB1.

Is tetraethyl lead poison affecting contemporary indigenous suicides in Ontario, Canada?

Prior to the mid-1980s, suicide in Indigenous population in Northwestern Ontario, Canada, was rare, occurring at rates of 1-2 per year among over 20 communities. By the early 1990s, the completed suicide rates in the same communities were among the highest in the world. Prior to the outbreak of the suicide epidemic, sniffing of gasoline containing tetraethyl was common in many communities. Existing literature confirms that tetraethyl lead poisoning is associated with alterations to the amyloid-ß protein precursor and amyloid-ß as well as the 5-HT-1B receptor. The presence of this risk factor within the population warrants further inquiry.

English language YouTube videos as a source of lead poisoning-related information: a cross-sectional study.

Exposure to lead is detrimental to children's development. YouTube is a form of social media through which people may learn about lead poisoning. The aim of this cross-sectional study was to analyze the variation in lead poisoning-related YouTube contents between different video sources. The 100 most viewed lead poisoning-related videos were manually coded, among which, 50 were consumer-generated, 19 were created by health care professionals, and 31 were news. The 100 videos had a total of more than 8.9 million views, with news videos accounting for 63% of those views. The odds of mentioning what lead poisoning is, how to remove lead, and specifically mentioning the danger in ages 1-5 because of rapid growth among videos created by health care professionals were 7.28 times (Odds ratio, OR = 7.28, 95% CI, 2.09, 25.37, p = 0.002); 6.83 times (OR = 6.83, 95% CI, 2.05, 22.75, p = 0.002) and 9.14 times (OR = 9.14, CI, 2.05, 40.70, p = 0.004) that of consumer-generated videos, respectively. In this study, professional videos had more accurate information regarding lead but their videos were less likely to be viewed compared to consumer-generated videos and news videos. If professional videos about lead poisoning can attract more viewers, more people would be better informed and could possibly influence policy agendas, thereby helping communities being affected by lead exposure.

Crianças e adolescentes intoxicados por chumbo: práticas maternas e problemas de comportamento / Children and adolescents with lead poisoning: Childrearing practices and behavioral problems / Los niños y adolescentes envenenados por plomo: las prácticas maternas y trastornos de conducta

Este estudo teve por objetivo avaliar as práticas educativas maternas em crianças e adolescentes intoxicados por chumbo, bem como sua correlação com problemas de comportamento nos filhos. Foi utilizada uma versão reduzida do IEP para avaliar as práticas maternas e o SSRS-BR, versão professor, para problemas de comportamento. Participaram 155 estudantes, com idade média de 13 anos, pertencentes a três grupos: alta plumbemia (GAP), baixa plumbemia (GBP) e grupo de comparação (GC) e suas respectivas mães e professores. Os resultados indicaram que as mães das crianças do grupo GBP utilizavam mais práticas indutivas, menos coerção e mais negligência que os outros dois grupos. A análise de correlação indicou também que estratégias parentais inconsistentes estão associadas a maior probabilidade de emissão de problemas de comportamento pelos filhos. Os resultados sugerem uma associação entre as práticas educativas adotadas pelas mães e as condições de contaminação por chumbo dos filhos.

This study aimed to investigate childrearing practices as related to children and adolescents poisoned by lead, and their correlation with behavioral problems. The authors used a reduced version of the Inventory of Parental Styles (IEP) to assess parenting practices and the SSRS-BR for behavioral problems. Participants included 155 children and adolescents with an average age of 13 years who belonged to three groups: high blood-lead (GAP), low blood-lead (GBP) and a comparison group (GC); and their respective mothers and teachers. The results show GBP’s mothers used more inductive practices, less coercion and more neglect than the other two groups. The correlation analysis also indicated that inconsistent parenting strategies are associated with higher probability of emission of behavioral problems in the children. The results suggest an association between the childrearing practices adopted by mothers and lead contamination conditions of the children.

El presente estudio tuvo como objetivo evaluar prácticas parentales con niños intoxicados por plomo y su correlación con los trastornos de conducta. Se utilizó una versión reducida del IEP (Inventario de Estilos Parentales) para evaluar las prácticas maternas y la versión maestro del SSRS-BR (Sistema de evaluación de habilidades sociales) para evaluar trastornos de conducta. Participaron 155 estudiantes, con edad media de 13 años y junto a sus madres y maestros, pertenecientes a tres grupos: plomo elevado en la sangre (GAP), bajos niveles de plomo (GBP) y grupos de comparación (GC). Los resultados indicaron que las madres de GBP utilizan prácticas más inductivas, con menos coacción y más negligentes que en los otros grupos. El análisis de correlación también indica que las prácticas parentales inconsistentes se asocian con una mayor probabilidad de emisión de los niños trastornos de conducta. Los resultados sugieren una asociación entre las prácticas adoptadas por las madres y las condiciones de contaminación de plomo de los niños.

Effects of intrauterine substance and postnatal violence exposure on aggression in children.

During the cocaine epidemic of the 1980s and early 1990s, many expressed fears that children with intrauterine cocaine exposure (IUCE) would grow up to be unusually violent. The present study examines the relationship of caregiver reports of school-age children's aggressive behavior with IUCE and postnatal exposure to violence. Respondents were 140 low-income, primarily African American children, ages 8-11, and each child's current primary caregiver from a longitudinal study evaluating potential long term sequelae of IUCE. Multiple regression analyses were used to investigate the independent and interactive effects of level of IUCE (None (n = 69), Lighter (n = 47), Heavier (n = 24)) and exposure to violence (Violence Exposure Scale for Children-Revised) on aggressive behavior (Child Behavior Checklist), while also controlling for other intrauterine substance exposures and additional contextual factors. Children's self-reported exposure to violence was significantly positively associated with caregivers' reports of aggressive behavior (ß = 2.17, P = .05), as was concurrent caregiver's psychiatric distress (ß = .15, P = .003). However, neither IUCE nor its interaction with exposure to violence showed a significant association with aggressive behavior. Findings suggest the importance of postnatal social environment rather than IUCE in predicting aggressive behavior in childhood.

Lead-induced impairments in the neural processes related to working memory function.

BACKGROUND: It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls. METHODOLOGY/PRINCIPAL FINDINGS: Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects.

Public understanding of local lead contamination.

Residents of Herculaneum, Missouri have been influential in shaping the management of contamination challenges resulting from the community's proximity to the last primary lead processing plant in the United States. This paper provides a nuanced examination of two perspectives of resident activist groups involved in lead-related controversy in Herculaneum. Ethnographic data collection and storyline analysis were used to trace the evolution in local views from resembling an industrialist-environmentalist dichotomy to more compromising positions associated with ecological modernization. Implications for characterizing public environmental perspectives in the US as beginning to entertain certain aspects of the ecological modernist paradigm are discussed.

Elevated manganese exposure and school-aged children's behavior: a gender-stratified analysis.

High levels of waterborne manganese have been associated with problematic behavior in school-aged children, however to date this has not been reported for children exposed to airborne manganese. The objective of the present study was to examine behavioral traits among children with exposure to airborne manganese from a ferro-manganese alloy plant, located in the metropolitan region of Salvador, Brazil. The study included 34 boys and 36 girls, aged 7-12 years, living in two communities within a 3-km radius from the plant. For each child, hair manganese levels (MnH) and blood lead (PbB) levels were analyzed by graphite furnace atomic absorption spectrometry. The Children's Behavior Check List (CBCL) (Portuguese version validated in Brazil) was administered to parents or caregivers, providing scale scores of internalizing (withdrawn, somatic complaints, and anxious/depressed scales), externalizing (disruptive and aggressive) behaviors and a separate scale for attention problems. Median and range for MnH and PbB were 11.48 µg/g (range: 0.52-55.74); 1.1 µg/dL (range: 0.5-6.1), respectively. Spearman correlation analyses showed that several behavioral indices were significantly correlated with MnH levels for girls, but not for boys: total externalizing behavior (rho=0.484 vs rho=0.041) and attention problem scores (rho=0.542 vs rho=0.003) coefficients were significantly at p<0.001 level, respectively for girls and boys. No significant correlation was observed with any of the internalizing sub-scales. A linear regression model was fitted with the total externalizing behavior, inattention and total CBCL scores as dependent variables, with log transformed MnH stratified by sex, adjusting for age and maternal IQ. Total externalizing behaviors and attention problem scores were significantly associated with girls' MnH levels but not with boys'. Adjusting for maternal IQ, the ß-coefficients for LogMnH associations with total externalizing and attention problems are 8.85 (95%CI 2.44-15.24) and 4.03 (95%CI 1.50-6.56) for girls. For boys, after adjusting for age, the ß-coefficients are 0.08 (95%CI 11.51-11.66) and -0.05 (95%CI 4.34-4.25), respectively. The findings of this study suggest a positive association between elevated Mn exposure and externalizing behavioral problems and inattention, with girls presenting more pronounced effects. Future studies on Mn exposure in children should attempt to further elucidate sex and/or gender differences in Mn exposed populations.

Neurotoxicity and biomarkers of lead exposure: a review.

Appropriate selection and measurement of lead biomarkers of exposure are critically important for health care management purposes, public health decision making, and primary prevention synthesis. Lead is one of the neurotoxicants that seems to be involved in the etiology of psychologies. Biomarkers are generally classified into three groups: biomarkers of exposure, effect, and susceptibility.The main body compartments that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurological disorders, such as brain damage, mental retardation, behavioral problems, nerve damage, and possibly Alzheimer's disease, Parkinsons disease, and schizophrenia. This paper presents an overview of biomarkers of lead exposure and discusses the neurotoxic effects of lead with regard to children and adults.

A clinical study of the effects of lead poisoning on the intelligence and neurobehavioral abilities of children.

BACKGROUND: Lead is a heavy metal and important environmental toxicant and nerve poison that can destruction many functions of the nervous system. Lead poisoning is a medical condition caused by increased levels of lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and issues, including the central nervous system. It interferes with the development of the nervous system, and is therefore particularly toxic to children, causing potentially permanent neural and cognitive impairments. In this study, we investigated the relationship between lead poisoning and the intellectual and neurobehavioral capabilities of children. METHODS: The background characteristics of the research subjects were collected by questionnaire survey. Blood lead levels were detected by differential potentiometric stripping analysis (DPSA). Intelligence was assessed using the Gesell Developmental Scale. The Achenbach Child Behavior Checklist (CBCL) was used to evaluate each child's behavior. RESULTS: Blood lead levels were significantly negatively correlated with the developmental quotients of adaptive behavior, gross motor performance, fine motor performance, language development, and individual social behavior (P < 0.01). Compared with healthy children, more children with lead poisoning had abnormal behaviors, especially social withdrawal, depression, and atypical body movements, aggressions and destruction. CONCLUSION: Lead poisoning has adverse effects on the behavior and mental development of 2-4-year-old children, prescribing positive and effective precautionary measures.