Trust and subjective knowledge influence perceived risk of lead exposure

Lead exposure is a persistent environmental hazard that poses risks to human health. But motivating protective action is challenging with this low visibility hazard whose health effects are often subtle and chronic. Higher risk perception is generally associated with taking protective measures, so public health efforts prioritize risk messaging. Yet, little is known about perceptions of lead exposure risk among the U.S. public. Using cross-sectional data from a national survey of 1035 U.S. residents, we measured the role of trust in government management of lead and subjective knowledge about lead as predictors of perceived risk of lead exposure, controlling for demographic and environmental factors. We also assessed if subjective knowledge moderated the relationship between trust and perceived risk. Our results reveal positive relationships between trust in government management of lead, subjective knowledge about lead, and risk perception, which we attribute in part to the important role government agencies play in secondary prevention, or communicating the risks of environmental lead exposure. We also found that younger people and people living in a house built before lead paint regulations passed in 1978 perceived higher lead risks. Our findings suggest that general communication about lead risks should aim to increase people's subjective knowledge in a consistent and balanced way that improves trust in government messengers.

Environmental chemical-wide associations with immune biomarkers in US adults: A cross-sectional analysis

Environmental chemical exposures influence immune system functions, and humans are exposed to a wide range of chemicals, termed the chemical "exposome". A comprehensive, discovery analysis of the associations of multiple chemical families with immune biomarkers is needed. In this study, we tested the associations between environmental chemical concentrations and immune biomarkers. We analyzed the United States cross-sectional National Health and Nutrition Examination Survey (NHANES 1999-2018). Chemical biomarker concentrations were measured in blood or urine (196 chemicals, 17 chemical families). Immune biomarkers included counts of lymphocytes, neutrophils, monocytes, basophils, eosinophils, red blood cells, white blood cells, and mean corpuscular volume. We conducted separate survey-weighted, multivariable linear regressions of each log2-transformed chemicals on immune measures, adjusted for relevant covariates. We accounted for multiple comparisons using a false discovery rate (FDR). Among 45,528 adult participants, the mean age was 45.7 years, 51.4% were female, and 69.3% were Non-Hispanic White. 71 (36.2%) chemicals were associated with at least one of the eight immune biomarkers. The most chemical associations (FDR<0.05) were observed with mean corpuscular volume (36 chemicals) and red blood cell counts (35 chemicals). For example, a doubling in the concentration of cotinine was associated with 0.16 fL (95% CI: 0.15, 0.17; FDR<0.001) increased mean corpuscular volume, and a doubling in the concentration of blood lead was associated with 61,736 increased red blood cells per μL (95% CI: 54,335, 69,138; FDR<0.001). A wide variety of chemicals, such as metals and smoking-related compounds, were highly associated with immune system biomarkers. This environmental chemical-wide association study identified chemicals from multiple families for further toxicological, immunologic, and epidemiological investigation.

Lead exposure aggravates glucose metabolism disorders through gut microbiota dysbiosis and intestinal barrier damage in high-fat diet-fed mice

BACKGROUND

Lead (Pb) is an ancient toxic metal and is still a major public health issue. Our previous study found that Pb exposure promotes metabolic disorders in obese mice, but the molecular mechanisms remain unclear. The present study explored the effects of Pb exposure on glucose homeostasis in mice fed a normal diet (ND) and high-fat diet (HFD) from the perspective of gut microbiota.

RESULTS

Pb exposure had little effect on glucose metabolism in ND mice, but exacerbated hyperglycemia and insulin resistance, and impaired glucose tolerance in HFD mice. Pb exposure impaired intestinal tight junctions and mucin expression in HFD mice, increasing intestinal permeability and inflammation. Moreover, Pb exposure altered the composition and structure of the gut microbiota and decreased short-chain fatty acids (SCFAs) levels in HFD mice. Correlation analysis revealed that the gut microbiota and SCFAs were significantly correlated with the gut barrier and glucose homeostasis. Furthermore, the fecal microbiota transplantation from Pb-exposed HFD mice resulted in glucose homeostasis imbalance, intestinal mucosal structural damage and inflammation in recipient mice. However, Pb did not exacerbate the metabolic toxicity in HFD mice under depleted gut microbiota.

CONCLUSION

The findings of the present study suggest that Pb induces impairment of glucose metabolism in HFD mice by perturbing the gut microbiota. Our study offers new perspectives on the mechanisms of metabolic toxicity of heavy metals and demonstrates that the gut microbiota may be a target of action for heavy metal exposure. © 2023 Society of Chemical Industry.

Association between Urinary Lead and Female Breast Cancer: A Population-Based Cross-Sectional Study

BACKGROUND

Previous studies have explored the relationship between serum lead levels and the risk of female breast cancer (FBC). However, it is still uncertain whether urinary lead levels are associated with FBC. This study aimed to investigate the potential association between urinary lead and FBC.

METHODS

A cross-sectional case-control study was conducted using the National Health and Nutrition Examination Survey (NHANES), which is a series of cross-sectional, nationally representative surveys of the United States population consisting of 10 survey waves from 1999 to 2018. This study analyzed a total of 2795 female participants (≥20 years), consisting of 210 participants with FBC and 2585 healthy controls. Urinary lead was detected using Inductively Coupled Plasma-Mass Spectrometry, which was divided into four levels by using quartiles-defining cut points. Multivariate logistic regression was used to analyze the association between urinary lead and FBC.

RESULTS

Multivariate logistic regression revealed that urinary lead was positively correlated with FBC (Odds ratio [OR], 2.16; 95% confidence interval [CI]: [1.18, 3.95], p < 0.05) in a fully adjusted model. There were significantly increased ORs of FBC in quartile 4 (Q4) and quartile 3 (Q3), compared with the lowest quartile 1 (Q1) (Q4, OR = 1.48, 95% CI [0.89, 2.48]; Q3: OR = 1.01, 95% CI [0.59, 1.73], p for trend = 0.021). No significant interaction effects were observed between urinary lead levels and FBC between the subgroups (age, race, educational status, body mass index (BMI), marital status, family income to poverty ratio, hypertension status, diabetes status, renal function status, smoking history, ever been pregnant, oral contraceptive use, occupation classification, etc.) (All interaction p-value > 0.05).

CONCLUSIONS

Urinary lead is likely positively associated with FBC in the US population.

Health risk assessment of workers exposed to lead dust in informal e-waste recycling workshops

Informal recycling of electronic waste (e-waste) has attracted significant attention due to its economic benefits and rapid growth rate in many parts of the world. Unfortunately, unsafe conditions of recycling workshops possess chronic exposure to workers and lead to elevated blood lead concentrations (BLCs). Upon measuring the lead concentration in the dust of recycling workshops and the e-wastes in southwestern region of Iran, the related health risks were assessed in 30 exposed workers and 30 non-exposed habitants cases based on the determination of BLC. The average BLCs in exposed workers and non-exposed habitants cases were 24 μg/dL and 7 μg/dL, respectively. The geo-accumulation index (Igeo) revealed heavy contamination of dust in informal e-waste recycling workshops (IERWs) (5023 μg/kg) and significantly lower levels in unexposed areas (49 μg/kg). Health risk assessment indicated that lead exposure from IERWs appears to be a potential threat to workers and indirectly to their families.

[Lead exposure aggravates Aβ1-42-induced microglial activation and copper ion accumulation in microglial cells]

OBJECTIVE

To investigate the effect of lead (Pb) exposure on Aβ1-42-induced microglial activation and copper ion accumulation in microglial cells and explore the regulatory mechanism of Pb-induced aggravation of Alzheimer's disease (AD)-like pathology.

METHODS

Cultured microglial BV2 cells were treated with different concentrations of Aβ1-42, lead acetate or their combination for 12 h, and the changes in cell viability and morphology were evaluated. Immunofluorescence assay was performed to detect iNOS and oxidative stress level in the treated cells, and the release of inflammatory factors was detected using ELISA. Western blotting and inductively coupled plasma-mass spectrometry (ICP-MS) were used to detect the expressions of CTR1 and ATP7A proteins and copper content in the cells.

RESULTS

Treatment with 15 and 20 μmol/L Aβ1-42 for 12 h significantly lowered the viability of BV2 cells. Treatment with Aβ1-42 at 10 μmol/L for 12 h obviously increased the release of iNOS, TNF-α and IL-6 in the cells (P<0.05), and its combination with 15 or 20 μmol/L lead acetate more strongly lowered BV2 cell viability (P<0.05). Compared with 10 μmol/L Aβ1-42 treatment alone, 10 μmol/L Aβ1-42 combined with 10 μmol/L lead acetate for 12 h caused more obvious microglial activation, as manifested by enlarged cell bodies, increased cell protrusions and elongation, enhanced release of iNOS, TNF-α, IL-6, IL-1β and ROS, and increased intracellular copper ion accumulation and expression of copper transporter CTR1 (P<0.05). Compared with the conditioned medium from activated BV2 cells, which caused obvious injuries in hippocampal neuron HT22 cells (P<0.001), the medium from BV2 cells treated with NAC and the copper ion chelating agent TM caused milder injuries in HT22 cells (P<0.05).

CONCLUSION

Lead exposure aggravates neuronal damage caused by Aβ1-42-treated microglial cells by increasing copper ion accumulation, oxidative stress, and inflammatory factor release to trigger microglial activation.

Parenting and Lead Mitigation at Home: A Multifaceted Community Partnership Model Promoting Parent Engagement in Lead Exposure Prevention

Young children are at high risk of lead poisoning, which can damage early cognitive and behavioral development and have long-lasting impacts. Home environments are persistent sources of exposure for children in urban, low-income settings. Community-academic partnerships are essential for public health intervention strategies addressing residential household lead exposure, yet community organization staff and home visitors often experience strain and burnout. We describe Parenting and Lead Mitigation at Home, a multifaceted partnership project to (a) develop and implement a community-based, peer-delivered education program for parents of young children in neighborhoods at risk for home lead exposure and (b) support the home visitors delivering programming. We developed, delivered, and initially evaluated Lead 101, a lead-exposure prevention curriculum informed by the Community Organizing and Family Issues (COFI) model. The goals were to educate parents around lead exposure risks and empower parents to reduce their child's risk. We developed a novel Reflective Practice pilot curriculum designed to provide emotional support to peer educators and community organization staff who delivered home-based programming. We trained 11 peer educators who delivered Lead 101 to 62 families. We pilot-tested the Reflective Practice curriculum with five community organization staff. The implementation process and pilot evaluation data suggest increased parent knowledge and self-efficacy regarding mitigation of home-based lead hazards, and high satisfaction with reflective practice. Using this model to develop multifaceted partnerships among universities, community-based organizations, and focal communities may facilitate community-engaged program development for families and systematic support for individuals working directly with families, thereby indirectly promoting child health and well-being.

Hyperhalophilic Diatom Extract Protects against Lead-Induced Oxidative Stress in Rats and Human HepG2 and HEK293 Cells

This work investigated the protective effects of microalga Halamphora sp. extract (HExt), a nutraceutical and pharmacological natural product, on human lead-intoxicated liver and kidney cells in vitro and in vivo in Wistar rats. The human hepatocellular carcinoma cell line HepG2 and the human embryonic kidney cell line HEK293 were used for the in vitro study. The analysis of the fatty acid methyl esters in the extract was performed via GC/MS. The cells were pretreated with HExt at 100 µg mL^-1, followed by treatment with different concentrations of lead acetate, ranging from 25 to 200 µM for 24 h. The cultures were incubated (5% CO, 37 °C) for 24 h. Four groups, each containing six rats, were used for the in vivo experiment. The rats were exposed to subchronic treatment with a low dose of lead acetate (5 mg kg^-1 b.w. per day). Pretreating HepG2 and HEK293 cells with the extract (100 µg mL^-1) significantly (p < 0.05) protected against the cytotoxicity induced by lead exposure. For the in vivo experiment, the biochemical parameters in serum-namely, the level of malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)-were measured in the organ homogenate supernatants. HExt was found to be rich in fatty acids, mainly palmitic and palmitoleic acids (29.464% and 42.066%, respectively). In both the in vitro and in vivo experiments, cotreatment with HExt protected the liver and kidney cell structures and significantly preserved the normal antioxidant and biochemical parameters in rats. This study discovered the possible protective effect of HExt, which could be beneficial for Pb-intoxicated cells.

The Role of Protein Intake on the Total Milk Protein in Lead-Exposed Lactating Mothers

Protein is an essential macronutrient for the growth and development of infants. Protein levels in lactating mothers are dynamic and influenced by various factors, particularly the environment and maternal characteristics. Therefore, this study aimed to evaluate the complex correlation between maternal blood lead levels (BLLs), maternal diet, and total milk protein. The Kruskal-Wallis test was used to compare total milk protein in the three groups of lead exposure, while Spearman's correlation was used to assess the correlation between maternal diet, BLLs, and total milk protein. The multivariate analysis used multiple linear regression. The results showed that the median of maternal BLLs and total milk protein were 3.3 µg/dL and 1.07 g/dL, respectively. Maternal protein intake and current BMI had a positive correlation with total milk protein, while BLLs had a negative correlation. BLLs ≥ 5 μg/dL had the most significant impact on reducing the total milk protein (p = 0.032). However, increasing maternal protein intake can effectively maintain total milk protein levels in mothers with BLLs under 5 μg/dL (p < 0.001). It is crucial to measure BLLs in lactating mothers residing in areas exposed to lead because high maternal protein intake can only maintain total milk protein levels when the BLLs are <5 μg/dL.

Racialized experience, biomarkers of lead exposure, and later-life cognition: a mediation analysis

We evaluated the role of the neurotoxicant lead (Pb) in mediating racial disparities in later-life cognition in 1,085 non-Hispanic Black and 2,839 non-Hispanic white participants in NHANES (1999-2002, 2011-2014) 60+ years of age. We operationalized Black race as a marker for the experience of racialization and exposure to systemic racism. We estimated patella bone Pb via predictive models using blood Pb and demographics. Concurrent cognition (processing speed, sustained attention, working memory) was measured by the Digit Symbol Substitution Test (DSST) and a global measure combining four cognitive tests. To obtain the portion mediated, we used regression coefficients (race on Pb * Pb on cognitive score)/(race on cognitive score), adjusting for age, NHANES cycle, and sample weights. Other confounder adjustment (education, poverty income ratio, smoking) was limited to the mediator-outcome (i.e., Pb-cognition) pathway because these factors do not lie upstream of race and so cannot confound associations with race. Pb was estimated to mediate 0.6% of the association between race and global cognition, and 4% of the DSST. Our results suggest that later-life cognitive health disparities may be impacted by avoidable lead exposure driven by environmental injustice, noting that a large proportion of the pathway of systemic racism harming cognition remains.

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.

Predicting Low-Level Childhood Lead Exposure in Metro Atlanta Using Ensemble Machine Learning of High-Resolution Raster Cells

Low-level lead exposure in children is a major public health issue. Higher-resolution spatial targeting would significantly improve county and state-wide policies and programs for lead exposure prevention that generally intervene across large geographic areas. We use stack-ensemble machine learning, including an elastic net generalized linear model, gradient-boosted machine, and deep neural network, to predict the number of children with venous blood lead levels (BLLs) ≥2 to <5 µg/dL and ≥5 µg/dL in ~1 km2 raster cells in the metro Atlanta region using a sample of 92,792 children ≤5 years old screened between 2010 and 2018. Permutation-based predictor importance and partial dependence plots were used for interpretation. Maps of predicted vs. observed values were generated to compare model performance. According to the EPA Toxic Release Inventory for air-based toxic release facility density, the percentage of the population below the poverty threshold, crime, and road network density was positively associated with the number of children with low-level lead exposure, whereas the percentage of the white population was inversely associated. While predictions generally matched observed values, cells with high counts of lead exposure were underestimated. High-resolution geographic prediction of lead-exposed children using ensemble machine learning is a promising approach to enhance lead prevention efforts.

The more you know: Insights from integrated pre-visit surveys in a pediatric environmental health center

The Pediatric Environmental Health Center (PEHC) at Boston Children's Hospital is a specialty referral clinic that provides consultation for approximately 250 patients annually. Identifying environmental hazards is key for clinical management. Exposure concerns include lead, mold, pesticides, perfluoroalkyl substances (PFAS), impaired air quality, and more. Our goal was to identify concerns and visit priorities of our patient population to guide visits. A 47-question pre-visit survey was created exploring potential environmental hazards and administered prior to visits using a platform integrated into the electronic medical record (EMR). The study group was a convenience sample of patients from June 2021 to June 2022. Of 204 total visits, 101 surveys were submitted, yielding a response rate of 49.5%. 66/101 (65.3%) were surveys from initial consultations used for descriptive analysis. The majority of patients were seen for a chief complaint of lead exposure (90.1%). Most respondents had concerns about peeling paint (40.0%), and those reporting peeling paint were more likely to report additional concerns [75.0%, p < 0.001]. Other concerns highlighted were mold (15.2%), pests (15.2%), asbestos (10.6%), air pollution (9.1%), temperature regulation (7.6%), pesticides (6.1%), PFAS (4.5%), and formaldehyde (4.5%). A knowledge gap was identified; 45.5% (30/66) respondents responded "no" to the question asking if the Poison Control Center phone number was stored in their phone. This study illustrates how the implementation of a pre-visit EMR integrated survey engages families, informs clinical care, and serves as a point-of-care education tool for specific knowledge gaps. Findings will guide development of future environmental health screeners.

Dietary fiber ameliorates lead-induced gut microbiota disturbance and alleviates neuroinflammation

Dietary fiber (DF) is a carbohydrate from the edible part of plants and has the functions of promoting gastrointestinal motility, regulating gut microbiota (GM) and improving health. Lead is a non-essential toxic heavy metal that can accumulate in the environment over time and enter the body through the respiratory tract, skin and gastrointestinal tract. Lead not only causes disturbances in GM but also leads to loss of homeostasis of immune functions, causes neuronal damage and results in neuroinflammation. The scientific literature has reported that DF had anti-inflammatory activity as a natural product. This review highlights the role of DF and its metabolic products in alleviating lead-induced neuroinflammation by inducing changes in the species and quantity of GM and regulating the immune system, providing a potential dietary protective strategy for lead-induced disease. © 2022 Society of Chemical Industry.

Potential Health Risks of Lead Exposure from Early Life through Later Life: Implications for Public Health Education

Lead (Pb) exposure has been a serious environmental and public health problem throughout the world over the years. The major sources of lead in the past were paint and gasoline before they were phased out due to its toxicity. Meanwhile, people continue to be exposed to lead from time to time through many other sources such as water, food, soil and air. Lead exposure from these sources could have detrimental effects on human health, especially in children. UNICEF reported that approximately 800 million children have blood lead levels (BLLs) at or above 5 micrograms per deciliter (µg/dL) globally. This paper reports on the potential risks of lead exposure from early life through later life. The articles used in this study were searched from databases such as Springer, Science Direct, Hindawi, MDPI, Google Scholar, PubMed and other academic databases. The levels of lead exposure in low income and middle-income countries (LMICs) and high-income countries (HICs) were reported, with the former being more affected. The intake of certain nutrients could play an essential role in reducing (e.g., calcium and iron) or increasing (e.g., high fat foods) lead absorption in children. Elevated blood lead levels may disturb the cells' biological metabolism by replacing beneficial ions in the body such as calcium, magnesium, iron and sodium. Once these ions are replaced by lead, they can lead to brain disorders, resulting in reduced IQ, learning difficulties, reduced attention span and some behavioral problems. Exposure to lead at an early age may lead to the development of more critical problems later in life. This is because exposure to this metal can be harmful even at low exposure levels and may have a lasting and irreversible effect on humans. Precautionary measures should be put in place to prevent future exposure. These will go a long way in safeguarding the health of everyone, most especially the young ones.

Trends in global burden of diseases attributable to lead exposure in 204 countries and territories from 1990 to 2019

Background

Lead hazards are ubiquitous in the environment, and lead exposure has been proved to damage human health. Nevertheless, there is limited data on the global burden of diseases attributable to lead exposure. In this study, we evaluated the temporal-spatial trend of disease burden caused by lead exposure in 204 countries and territories from 1990 to 2019.

Methods

Based on Global Burden of Disease (GBD) Study 2019, deaths, disability-adjusted life years (DALYs), age-standardized mortality rate (ASMR) and DALYs rate (ASDR) were estimated by region, country, sex and age. The estimated annual percentage change (EAPC) was calculated to assess the temporal trends of ASMR and ASDR between 1990 and 2019.

Results

Global deaths increased from 0.53 (95% UI: 0.31, 0.77) to 0.90 (95% UI: 0.55, 1.29) million, and the number of DALYs increased from 16.02 (95% UI: 10.32, 22.17) to 21.68 (95% UI: 13.81, 30.30) million between 1990 and 2019. China, India and Bangladesh were top three countries with the largest number of deaths and DALYs in 2019. The ASMR (per 100,000 population) decreased from 14.47 (95% UI: 8.40, 21.43) to 11.48 (95% UI: 7.00, 16.49) with EAPC of -0.75 (95% UI: -0.87, -0.64), and the ASDR (per 100,000 population) decreased from 378.01 (95% UI: 240.55, 524.18) to 267.52 (95% UI: 170.57, 373.44) with EAPC of -1.19 (95% UI: -1.32, -1.07). Most of disease burden of lead exposure occurred in the men and elderly population. Stroke and ischemic heart disease were two key sources of disease burden of lead exposure. Also, a negative association between sociodemographic index (SDI) and disease burden of lead exposure was observed.

Conclusions

Lead exposure poses a significant disease burden globally, and is still a great threat to public health. Primary prevention measures of reducing lead exposure in the environment are essential.

A County-Level Program for the Evaluation of the Potential for Take-Home Lead Exposures Among Children in Michigan

OBJECTIVE

Take-home lead exposure involves lead dust inadvertently carried from the worksite by employees that becomes deposited in their homes and vehicles. We piloted a program in 2 counties in Michigan to investigate the countywide potential for take-home lead exposures across industries.

METHODS

During 2018-2020, we identified establishments through internet searches and industry-specific registries. We visited establishments with a physical storefront in-person; we attempted to contact the remaining establishments via telephone. We administered questionnaires at the establishment level to assess the presence of lead and the current use of practices meant to mitigate the potential for take-home lead exposures. We recruited workers for wipe sampling of lead dust from their vehicle floors to test for lead levels.

RESULTS

We identified 320 establishments with potential lead use or exposures. Questionnaire responses revealed widespread worker exposures to lead and a lack of education and implementation of best practices to prevent lead from leaving the worksite. Dust samples (n = 60) collected from employee vehicles showed a ubiquitous tracking of lead out of the workplace, with a range of 5.7 to 84 000 µg/ft2 and a geometric mean of 234 µg/ft2. Of the sample results, 95.0% were above the lead dust clearance levels for homes established by the US Environmental Protection Agency.

CONCLUSIONS

This work suggests that take-home lead exposures are widespread and may be important sources of lead exposure among children. It also demonstrates the feasibility of a program for the identification of establishments whose employees may be susceptible to taking lead dust home with them and whose children may subsequently be targeted for blood lead monitoring.

Lead exposure is non-linearly associated with subclinical myocardial injury in the general population without cardiovascular disease

Background and aims

Growing studies have focused on the effect of lead exposure on human circulatory system, while the relationship between lead exposure and subclinical myocardial injury (SC-MI) is still poorly known. Therefore, this study was to explore the effect of lead exposure on SC-MI.

Methods

The study included 6,272 individuals aged 40 and older without cardiovascular disease (CVD) from the third National Health and Nutrition Examination Survey. Blood lead was used as an alternative marker of lead exposure. Multivariable logistic regression models, restricted cubic spline and threshold effect analyses were performed to investigate the effect of blood lead on SC-MI.

Results

After adjusting for age, sex, race, diabetes, hypertension, systolic blood pressure, body mass index, waist-to-hip ratio, triglycerides, total cholesterol, creatinine, fasting plasma glucose and hemoglobin Alc, higher blood lead level was independently related to higher risk of SC-MI (OR 1.047, 95% CI [1.018, 1.077]; P = 0.003). Restricted cubic spline curve showed that there was a non-linear correlation between blood lead and SC-MI. Threshold effect analysis determined that the inflection point of blood lead was 3.8 ug/dl. When the blood lead level was higher than 3.8 ug/dl, there was an independent positive correlation between blood lead level and the risk of SC-MI (OR 1.031, 95% CI [1.009, 1.053]; P < 0.01). And similar associations were also observed among subgroups of male, ≤60 years, >60 years, never smoker, non-Hispanic White, non-Hispanic Black or without hypertension and diabetes.

Conclusions

Blood lead was non-linearly related to SC-MI in population free from CVD.

Blood Lead Levels among Non-Occupationally Exposed Pregnant Women in Southern Thailand

Lead (Pb) is a heavy metal that is toxic to humans, especially children and pregnant women. In Thailand, guidelines exist to minimize lead exposure in pregnant women working in lead-related occupations. However, no guidelines exist for pregnant women who are not employed in these economic sectors. This cross-sectional study aimed to examine blood lead levels (BLLs) and related risk factors among 80 non-occupationally exposed pregnant women from the general population living in Nakhon Si Thammarat province, Southern Thailand. BLLs were determined by graphite furnace atomic absorption spectrophotometry. A validated questionnaire was adopted to interview participants which included demographic, consumer goods, supplement intake, and health factors. The mean BLL was 4.68 ± 1.55 µg/dL (95% CI 4.33-5.02) and 42.50% had BLLs ≥ 5 µg/dL. Higher education was the only demographic factor associated with BLLs ≥ 5 µg/dL (aOR 0.16, 95% CI 0.03-0.80, p = 0.027). Systolic blood pressure was also associated with BLLs ≥ 5 µg/dL (aOR 5.00, 95% CI 1.23-17.16, p = 0.023). However, consumer goods and supplement intake were not associated with BLLs. Our results indicate that pregnant women from the general population who were not in the risk exposure group had lead in their bodies. Except for education, demographics were not associated with pregnant women with BLLs. However, with health factors, even low BLLs had a small effect on systolic blood pressure. These data suggest a need for promoting health education and health interventions to prevent the dangers of lead exposure, especially for pregnant women and children.

Lead Exposure in Infancy and Subsequent Growth in Beninese Children

Studies suggest that elevated postnatal blood lead levels (BLLs) are negatively associated with child growth. This study aimed to investigate the associations of childhood BLLs at age one year and growth outcomes at age six years (n = 661) in a cohort of children in Allada, Benin. The growth outcomes studied are weight-for-age Z-score (WAZ), height-for-age Z-score (HAZ), BMI-for-age Z-score (BMIZ), weight-for-height Z-score (WHZ), head circumference (HC), growth velocities, underweight, stunting, and wasting. Multivariable regression models examined the associations between BLLs and growth outcomes, with adjustment for potential confounders. The geometric mean BLLs was 59.3 μg/L and 82% of children had BLLs >35 μg/L at the age of 12.8 months. After adjusting for confounding factors, no overall association was found between BLL quartiles and HAZ, WAZ, BMIZ, WHZ, growth velocities, wasting, and underweight. However, boys in the highest quartile had a 1.02 cm lower HC (95% CI: [−1.81, −0.24]) as compared to the lowest quartile. Furthermore, an increased odds of being stunted was observed in children in the highest quartile of exposure compared to the first (OR: 2.43; 95% CI: [1.11−5.33]) which remained statistically significant only among girls in sex-specific strata. Blood lead was found to be associated with an increased risk of childhood stunting and a lower head circumference in a resource-limited setting.

Racial residential segregation shapes the relationship between early childhood lead exposure and fourth-grade standardized test scores

Racial residential segregation (RRS) – defined here as the geographic separation of Black individuals and communities from other racial/ethnic groups into separate, unequal neighborhoods – fosters environments inimical to health through disinvestment of resources and concentration of disadvantages. Neighborhood environments influence children’s health and development, but relationships between RRS and cognitive development are poorly understood. We find that: (1) non-Hispanic Black children were more likely to experience multiple adverse exposures in early childhood, and (2) among non-Hispanic Black children, high levels of RRS augmented the detrimental effect of elevated blood levels on reading test scores. Non-linear models were used to model exposure to lead and RRS, and their interaction.

Racial/ethnic disparities in academic performance may result from a confluence of adverse exposures that arise from structural racism and accrue to specific subpopulations. This study investigates childhood lead exposure, racial residential segregation, and early educational outcomes. Geocoded North Carolina birth data is linked to blood lead surveillance data and fourth-grade standardized test scores (n = 25,699). We constructed a census tract-level measure of racial isolation (RI) of the non-Hispanic Black (NHB) population. We fit generalized additive models of reading and mathematics test scores regressed on individual-level blood lead level (BLL) and neighborhood RI of NHB (RINHB). Models included an interaction term between BLL and RINHB. BLL and RINHB were associated with lower reading scores; among NHB children, an interaction was observed between BLL and RINHB. Reading scores for NHB children with BLLs of 1 to 3 µg/dL were similar across the range of RINHB values. For NHB children with BLLs of 4 µg/dL, reading scores were similar to those of NHB children with BLLs of 1 to 3 µg/dL at lower RINHB values (less racial isolation/segregation). At higher RINHB levels (greater racial isolation/segregation), children with BLLs of 4 µg/dL had lower reading scores than children with BLLs of 1 to 3 µg/dL. This pattern becomes more marked at higher BLLs. Higher BLL was associated with lower mathematics test scores among NHB and non-Hispanic White (NHW) children, but there was no evidence of an interaction. In conclusion, NHB children with high BLLs residing in high RINHB neighborhoods had worse reading scores.

Using Small Area Prevalence Survey Methods to Conduct Blood Lead Assessments among Children

Introduction: Prevalence surveys conducted in geographically small areas such as towns, zip codes, neighborhoods or census tracts are a valuable tool for estimating the extent to which environmental risks contribute to children’s blood lead levels (BLLs). Population-based, cross-sectional small area prevalence surveys assessing BLLs can be used to establish a baseline lead exposure prevalence for a specific geographic region. Materials and Methods: The required statistical methods, biological and environmental sampling, supportive data, and fieldwork considerations necessary for public health organizations to rapidly conduct child blood lead prevalence surveys at low cost using small area, cluster sampling methodology are described. Results: Comprehensive small area prevalence surveys include partner identification, background data collection, review of the assessment area, resource availability determinations, sample size calculations, obtaining the consent of survey participants, survey administration, blood lead analysis, environmental sampling, educational outreach, follow-up and referral, data entry/analysis, and report production. Discussion: Survey results can be used to estimate the geographic distribution of elevated BLLs and to investigate inequitable lead exposures and risk factors of interest. Conclusions: Public health officials who wish to assess child and household-level blood lead data can quickly apply the data collection methodologies using this standardized protocol here to target resources and obtain assistance with these complex procedures. The standardized methods allow for comparisons across geographic areas and over time.

Cardiovascular Mortality and Leaded Aviation Fuel: Evidence from Piston-Engine Air Traffic in North Carolina

Leaded fuel used by piston-engine aircraft is the largest source of airborne lead emissions in the United States. Previous studies have found higher blood lead levels in children living near airports where leaded aviation fuel is used. However, little is known about the health effects on adults. This study is the first to examine the association between exposure to aircraft operations that use leaded aviation fuel and adult cardiovascular mortality. We estimated the association between annual piston-engine air traffic and cardiovascular mortality among adults age 65 and older near 40 North Carolina airports during 2000 to 2017. We used several strategies to minimize the potential for bias due to omitted variables and confounding from other health hazards at airports, including coarsened exact matching, location-specific intercepts, and adjustment for jet-engine and other air traffic that does not use leaded fuel. Our findings are mixed but suggestive of adverse effects. We found higher rates of cardiovascular mortality within a few kilometers downwind of single- and multi-runway airports, though these results are not always statistically significant. We also found significantly higher cardiovascular mortality rates within a few kilometers and downwind of single-runway airports in years with more piston-engine air traffic. We did not consistently find a statistically significant association between cardiovascular mortality rates and piston-engine air traffic near multi-runway airports, where there was greater uncertainty in our measure of the distance between populations and aviation exposures. These results suggest that (i) reducing lead emissions from aviation could yield health benefits for adults, and (ii) more refined data are needed to obtain more precise estimates of these benefits. Subject Areas: Toxic Substances, Health, Epidemiology, Air Pollution, Ambient Air Quality. JEL codes: Q53, I18.

[Role of ferroptosis in cerebellar injury of mice following lead exposure]

OBJECTIVE

To investigate the role of ferroptosis in cerebellar injury of mice following lead exposure.

METHODS

A total of forty SPF C57 mice were randomly divided into control group, low-dose lead exposure group, middle-dose lead exposure group and high-dose lead exposure group, with 10 mice in each group. Mice in three lead exposure groups were given 0.25, 0.50, 1.00 g/L lead acetate through drinking water for twelve weeks respectively. Lead concentration was detected by inductively coupled plasma mass spectrometer. The motor function was detected by beam walking test and open field test. Pathological changes of cerebellum in mice were observed by H&amp;E staining. Western blotting was used to detect the protein expression of transferrin receptor-1(TFR-1), ferroportin(FPN-1), solute carrier family 7 member 11(SLC7 A11), glutathione peroxidase 4(GPX4), NF-E2-related factor 2(Nrf2) and heme oxygenase-1(HO-1).

RESULTS

The lead concentration in cerebellum of mice in low lead group, medium lead group and high lead group were(1.05±0.11), (1.21±0.10) and(1.48±0.1) μg/g, respectively, which were significantly higher than that in the control group. The time to traverse the beam in low lead group, medium lead group and high lead group was 1.34, 1.64 and 2.02 folds of that in control group, respectively. Open field test showed that the central residence time and standing times of mice in low lead group, medium lead group and high lead group were significantly lower than that in control. Purkinje cells in the cerebellum of mice exposed to different doses of lead showed irregular arrangement, small cell bodies and deep staining, especially in the high lead group. The relative levels of iron in low lead group, medium lead group and high lead group was 1.77, 2.29 and 3.77 folds of that in control group, respectively. The content of MDA in cerebellum of mice in three lead exposure groups increased significantly, while the GHS decreased significantly. Compared with the control group, the expression of TFR-1 protein increased significantly in the lead exposure group, while the expression of FPN-1 protein decreased significantly only in the medium lead group and high lead group, which was 60% and 50% of the control group. Compared with the control group, the expressions of oxidative stress regulatory proteins SLC7 A11 and GPX4 in medium lead group and high lead group decreased significantly. Lead exposure significantly decreased the expression of Nrf2 and HO-1 protein in cerebellum, especially in high lead group.

CONCLUSION

In this experiment condition, lead may induce ferroptosis in cerebellum of mice, of which, Nrf2/HO-1 signaling pathway might be involved in, and then further result in motor dysfunction of mice.

The Association between Lead Exposure and Bone Mineral Density in Childhood and Adolescence: Results from NHANES 1999-2006 and 2011-2018

There are few studies on lead's effect on bone mineral density (BMD) in childhood. In this study, we examined the association between lead exposure and BMD among 13,951 children and adolescents aged 8-19 years from NHANES 1999-2006 and 2011-2018. The whole blood lead levels (BLLs) were used as lead exposure biomarkers, and total BMD, subtotal BMD, lumbar spine BMD and limb BMD were used as outcome variables. The survey weighted multivariable generalized additive models (GAMs) with smoothing terms were used to explore the association between blood lead levels and BMDs, adjusted for age, sex, race/ethnicity, height, weight, family-income-to-poverty ratio and blood cadmium. Subgroup analyses stratified by sex and bony sites were further performed. We found an N-shaped curve association between BLLs and total BMD, subtotal BMD and limb BMD for males and females, whereas the association between BLLs and lumbar spine BMD was only significantly negative for females. The findings suggested that lead exposure had different effects on BMD of different bony sites (highly cortical or trabecular regions) in childhood and adolescence and had different effects on the same bone among different ages population and/or at different levels.

The role of probiotic intervention in regulating gut microbiota, short-chain fatty acids and depression-like behavior in lead-exposed rats

OBJECTIVES

The aim of this study was to observe the depression-like behavior changes of rats exposed to lead with or without probiotic intervention, and to investigate changes in the gut microbiota and fecal short-chain fatty acids (SCFAs) levels after lead exposure, and the possible functions of probiotics in this process.

MATERIAL AND METHODS

Adult male Sprague Dawley rats were exposed to a 300 mg/l lead acetate solution for 24 weeks, with or without probiotic (freeze-dried powder containing Lactobacillus and Bifidobacterium: 6 billion live bacteria/2 g) intervention in weeks 17-24. The sucrose preference test (SPT), the forced swim test (FST), and the tail suspension test (TST) were preformed to study the depression- like behaviors of these rats. The alteration of rat gut microbiota induced by lead exposure was analyzed by 16S rRNA sequencing, and the levels of fecal SCFAs were detected using gas chromatography.

RESULTS

Neurobehavioral tests showed that lead exposure induced depression-like behavior in rats, including reduced sucrose preference in the SPT, and increased immobility times in the FST and the TST. Sequencing and gas chromatography showed that lead exposure changed the structure and the phylogenetic diversity of the gut microbiota, as well as significantly altered the levels of SCFAs. Moreover, the depression-like behaviors, and the changes in both gut microbiota and SCFAs, could be mitigated by probiotic intervention.

CONCLUSIONS

Lead exposure not only changes the structure and diversity of the gut microbiome but also affects metabolic function. Probiotic intervention may be a novel initiative for the prevention and treatment of neurological damage following lead exposure. Int J Occup Med Environ Health. 2022;35(1):95-106.

Geospatial Distributions of Lead Levels Found in Human Hair and Preterm Birth in San Francisco Neighborhoods

In San Francisco (SF), many environmental factors drive the unequal burden of preterm birth outcomes for communities of color. Here, we examine the association between human exposure to lead (Pb) and preterm birth (PTB) in 19 racially diverse SF zip codes. Pb concentrations were measured in 109 hair samples donated by 72 salons and barbershops in 2018-2019. Multi-method data collection included randomly selecting hair salons stratified by zip code, administering demographic surveys, and measuring Pb in hair samples as a biomarker of environmental exposure to heavy metals. Concentrations of Pb were measured by atomic emission spectrometry. Aggregate neighborhood Pb levels were linked to PTB and demographic data using STATA 16 SE (StataCorp LLC, College Station, TX, USA). Pb varied by zip code (p < 0.001) and correlated with PTB (p < 0.01). Increases in unadjusted Pb concentration predicted an increase in PTB (β = 0.003; p < 0.001) and after adjusting for poverty (β = 0.002; p < 0.001). Confidence intervals contained the null after further adjustment for African American/Black population density (p = 0.16), suggesting that race is more indicative of high rates of PTB than poverty. In conclusion, Pb was found in every hair sample collected from SF neighborhoods. The highest concentrations were found in predominately African American/Black and high poverty neighborhoods, necessitating public health guidelines to eliminate this environmental injustice.

Life History Traits in Two Drosophila Species Differently Affected by Microbiota Diversity under Lead Exposure

Simple Summary

Microbiota have a significant functional role in the life of the host, including immunity, lifespan and reproduction. Drosophila species are attractive model organisms for investigating microbiota diversity from different aspects due to their simple gut microbiota, short generation time and high fertility. Considering such an important role of the microbiota in the life of Drosophila, we investigated the extent to which lead (Pb), as one of the most abundant heavy metals in the environment, affects the microbiota and the fitness of this insect host. The results indicate that different factors, such as population origin and sex, may affect individual traits differently and this could be species-specific. In addition, there are members of microbiota that help the host to overcome environmental stress and they could play a key role in reducing the fitness cost in such situations. Studying the influence of microbiota on the adaptive response to heavy metals and the potential implications on overall host fitness is of great pertinence.

Abstract

Life history traits determine the persistence and reproduction of each species. Factors that can affect life history traits are numerous and can be of different origin. We investigated the influence of population origin and heavy metal exposure on microbiota diversity and two life history traits, egg-to-adult viability and developmental time, in Drosophila melanogaster and Drosophila subobscura, grown in the laboratory on a lead (II) acetate-saturated substrate. We used 24 samples, 8 larval and 16 adult samples (two species × two substrates × two populations × two sexes). The composition of microbiota was determined by sequencing (NGS) of the V3–V4 variable regions of the 16S rRNA gene. The population origin showed a significant influence on life history traits, though each trait in the two species was affected differentially. Reduced viability in D. melanogaster could be a cost of fast development, decrease in Lactobacillus abundance and the presence of Wolbachia. The heavy metal exposure in D. subobscura caused shifts in developmental time but maintained the egg-to-adult viability at a similar level. Microbiota diversity indicated that the Komagataeibacter could be a valuable member of D. subobscura microbiota in overcoming the environmental stress. Research on the impact of microbiota on the adaptive response to heavy metals and consequently the potential tradeoffs among different life history traits is of great importance in evolutionary research.

Testing Homes for Potential Sources of Lead Exposure as a High-School Science Project

High-school students tested soil, paint, and water for lead (Pb) in a total of 80 houses in their town of Pelham, New York, where blood-Pb data indicate relatively high levels of child exposure. All the samples were tested in the laboratory using established procedures but this was preceded by testing of soil and paint in the field with a kit by the students. The total Pb concentration in 32 of the 159 soil samples that were collected exceeded 400 ppm, the EPA standard for bare soil in residential areas where children play. Only 4 of the 118 tap water samples that were collected contained over 15 ppb Pb, with the data showing that flushing for 2 min clearly lowered Pb concentration further across the board. The highest risk of child exposure may be posed by old Pb-based paint, however, which was detected in 9 of the 48 samples that were tested. Residents were also the least willing to let the students test or sample their paint. High-school students could help reduce exposure in the many towns where child blood-Pb levels remain high today by identifying sources and, while doing so, learn about environmental science and measurement from this hands-on experience.

Global and gene-specific promoter methylation, and micronuclei induction in lead-exposed workers: A cross-sectional study

Perturbation of epigenetic regulation is a well-established mechanism for cancer but its role for lead (Pb)-associated toxicity has not been adequately investigated. We aimed to investigate whether occupational Pb exposure is associated with micronuclei (MN) frequency and to further explored the mediating roles of epigenetic gene regulation. All the Pb-exposed workers recruited from a Chinese acid battery factory, blood lead levels (BLLs) and MN frequency in lymphocytes were measured. In addition, methylation levels of seven genes (Line-1, RASSF1A, RUNX3, p16, CYP26C1, hMLH1, p15) were examined among 230 workers. Robust Poisson regression model was used to investigate the association between BLLs and MN frequency. Mediation analysis was used to explore the mediating role of specific DNA methylation. Among total 677 participants, 71% were male, median BLLs was 229.1 μg/L (P₂₅  = 155.5, P₇₅  = 319.3; ranged from 8.9 to 647.7 μg/L), mean MN frequency was 2.5‰ (SD = 1.8‰; ranged from 0 to 9‰). Results from base model, adjusted for age, sex, and body mass index, showed that MN frequency would increase 1.38 (95%confidential interval: 1.34, 1.43) per 100 μg/L increment in BLLs. Using categorized exposure variable analyses, a BLLs dose-response increase in MN frequency was observed: 2.74 (2.13, 3.51), 3.43 (2.73, 4.32), 4.41 (3.89, 5.01) to 6.86 (6.02, 7.81). Mediation analysis indicated that Line-1 methylation significantly mediated 3.6% of the association of BLLs with MN frequency. Occupational Pb exposure induces MN frequency in a dose-response relationship. Part of this association was mediated by Line-1 promotor methylation.

Midstream Players Determine Population-Level Behavior Change: Social Marketing Research to Increase Demand for Lead-Free Components in Pitcher Pumps in Madagascar

Lead (Pb) exposure through water contamination is an important issue at the intersection of public health and water, sanitation, and hygiene (WASH). Behavior-change programs designed to address this pressing problem rarely take a behavioral-science-informed approach, nor do they consider the role of intermediate players who often influence and support behavior change. Social marketing segments the population and focuses on the consumer/user throughout program development and implementation. To illustrate the social marketing process, this cross-sectional, qualitative design study investigates the use of Pb in the construction and maintenance of household pitcher pumps for potable water in Madagascar. A sample of 18 technicians were interviewed on their current practices, motivators, barriers, and communication channels for knowledge exchange. The results reveal the importance of peers, those considered experts or "market mavens", and the need for information on the dangers of Pb as an outdated practice for any future intervention. This study advances the notion of a design shift within engineering WASH projects, whereby social/behavioral approaches are used to consider the needs, concerns, and current behaviors of the consumer. We also advocate for engaging intermediate players who often influence behavior change in the rollout of an engineering innovation.

Combined Effect of Lead Exposure and Allostatic Load on Cardiovascular Disease Mortality-A Preliminary Study

This study explores the combined effect of lead (Pb) exposure and an index of chronic physiological stress on cardiovascular disease mortality using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 linked to 1999-2014 National Death Index data. Chronic physiological stress was measured using the allostatic load (AL) index, which was formed by analyzing markers from the cardiovascular, inflammatory, and metabolic systems, with Pb levels, assessed using blood lead levels (BLL). The dataset was analyzed with statistical techniques to explore (a) the relationship between Pb exposure and AL, and (b) the combined role of Pb and AL on cardiovascular disease mortality. Results indicated that AL was more elevated in those with BLLs above the 50th percentile in the US population and that those with elevated AL were more likely to have high BLL. Finally, the interaction of AL and BLL significantly increased the likelihood of cardiovascular disease mortality. These findings highlight the need for considering the totality of exposures experienced by populations to build holistic programs to prevent Pb exposure and reduce stressors to promote optimal health outcomes and reduce cardiovascular mortality risk.

Effect of chelation therapy on arrhythmogenic and basal ECG parameters of lead exposed workers

Lead exposure has etiological role on cardiovascular system diseases as hypertension, atherosclerosis, stroke, and arrhythmic events. In this study, we aimed to compare the basal and arrhythmogenic ECG parameters of lead exposed workers before and after chelation therapy and to evaluate the effect of acute change of blood lead levels on ECG. Fourty consecutive occupationally lead exposed workers were enrolled, demographic, blood, echocardiographic, and electrocardiographic data's were analyzed before and after chelation therapy. Pmax, P min, P Wave Dispersion, and QT Dispersion values which are arrhythmia predictors were significantly lower after chelation therapy compared to values before chelation therapy. Lead exposed workers are under the risk of ventricular and atrial arrythmias and chelation treatment has a positive effect on these parameters.

Environmental Risk Factors and Psychotic-like Experiences in Children Aged 9-10

OBJECTIVE

Research implicates environmental risk factors, including correlates of urbanicity, deprivation, and environmental toxins, in psychotic-like experiences (PLEs). The current study examined associations between several types of environmental risk factors and PLEs in school-age children, whether these associations were specific to PLEs or generalized to other psychopathology, and examined possible neural mechanisms for significant associations.

METHOD

The current study used cross-sectional data from 10,328 children 9-10 years old from the Adolescent Brain Cognitive Development (ABCD) Study. Hierarchical linear models examined associations between PLEs and geocoded environmental risk factors and whether associations generalized to internalizing/externalizing symptoms. Mediation models examined evidence of structural magnetic resonance imaging abnormalities (eg, intracranial volume) potentially mediating associations between PLEs and environmental risk factors.

RESULTS

Specific types of environmental risk factors, namely, measures of urbanicity (eg, drug offense exposure, less perception of neighborhood safety), deprivation (eg, overall deprivation, poverty rate), and lead exposure risk, were associated with PLEs. These associations showed evidence of stronger associations with PLEs than internalizing/externalizing symptoms (especially overall deprivation, poverty, drug offense exposure, and lead exposure risk). There was evidence that brain volume mediated between 11% and 25% of associations of poverty, perception of neighborhood safety, and lead exposure risk with PLEs.

CONCLUSION

Although in the context of cross-sectional analyses, this evidence is consistent with neural measures partially mediating the association between PLEs and environmental exposures. This study also replicated and extended recent findings of associations between PLEs and environmental exposures, finding evidence for specific associations with correlates of urbanicity, deprivation, and lead exposure risk.

Soil Lead (Pb) in New Orleans: A Spatiotemporal and Racial Analysis

Spatialized racial injustices drive morbidity and mortality inequalities. While many factors contribute to environmental injustices, Pb is particularly insidious, and is associated with cardio-vascular, kidney, and immune dysfunctions and is a leading cause of premature death worldwide. Here, we present a revised analysis from the New Orleans dataset of soil lead (SPb) and children’s blood Pb (BPb), which was systematically assembled for 2000–2005 and 2011–2016. We show the spatial–temporal inequities in SPb, children’s BPb, racial composition, and household income in New Orleans. Comparing medians for the inner city with outlying areas, soil Pb is 7.5 or 9.3 times greater, children’s blood Pb is ~2 times higher, and household income is lower. Between 2000–2005 and 2011–2016, a BPb decline occurred. Long-standing environmental and socioeconomic Pb exposure injustices have positioned Black populations at extreme risk of adverse health consequences. Given the overlapping health outcomes of Pb exposure with co-morbidities for conditions such as COVID-19, we suggest that further investigation be conducted on Pb exposure and pandemic-related mortality rates, particularly among Black populations. Mapping and remediating invisible environmental Pb provides a path forward for preventing future populations from developing a myriad of Pb-related health issues.

Chronic Low-Level Lead Exposure Increases Mesenteric Vascular Reactivity: Role of Cyclooxygenase-2-Derived Prostanoids

Lead (Pb) exposure causes hazardous effects as hypertension and other cardiovascular diseases. We evaluated whether chronic Pb exposure alters the peripheral vascular resistance measuring the vascular reactivity of mesenteric resistance arteries in rats to identify the underlying mechanisms that are associated to the development of Pb-induced hypertension. Mesenteric resistance arteries from lead-treated and untreated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) were used. Contractile responses to phenylephrine increased, while acetylcholine and sodium nitroprusside-induced relaxation was not affected by lead treatment. Endothelium removal and inhibition of NO synthase by L-NAME similarly enhanced the response to phenylephrine in untreated and lead-treated rats. The antioxidants apocynin and superoxide dismutase (SOD) did not affect vasoconstriction in either group. The vascular expression of cyclooxygenase-2 (COX-2) protein increased after lead exposure. The respective non-specific or specific COX-2 inhibitors indomethacin and NS398 reduced more strongly the response to phenylephrine in treated rats. Antagonists of EP1 (SC19220), TP (SQ29548), IP (CAY10441) and angiotensin II type 1 (losartan) receptors reduced vasoconstriction only in treated rats. These conclusions present further evidence that lead, even in small concentration, produces cardiovascular hazards being an environmental contaminant that account for lead-induced hypertension.

Inaction on Lead Despite the Relevant Knowledge: Predictors, Covariates, and Outreach Implications

Testing residential soil and paint for lead provides actionable information. By showing where and how much lead exists on the residence, it allows one to quantify risk and determine the best ways to reduce exposure along with the corresponding health and financial costs. For these reasons, several federal and state programs offer outreach to audiences on the benefits of testing residential soil and paint for lead. Not all individuals who know about lead’s adverse health effects, however, test their residence for lead, potentially limiting the actionable information that could have helped to reduce their exposure. Such individuals represent a challenge to outreach programs and the broader public health objectives. There is, thus, a need to understand who such individuals are and why they behave this way, allowing us to develop a specialized outreach program that addresses the problem by targeting the relevant sub-population. Using survey data, we quantitatively determine the profiles of individuals who, despite knowing about lead’s adverse health effects, are unlikely to test their residence for lead, finding statistically significant socio-economic predictors and behavioral covariates. We also find a geographic component to it, further helping outreach professionals learn how to allocate their limited resources.

Assessment of a Screening Questionnaire to Identify Exposure to Lead in Pregnant Women

Lead readily crosses the placenta and displays adverse effects on birth outcomes and neurodevelopment. Systematic identification of the risk of exposure during pregnancy is essential but rarely performed, probably due to hospital staff’s workload and their lack of awareness. We aimed to evaluate the relevance of a questionnaire to screen pregnant women for lead exposure. A cross-sectional, multicentre study was carried out on a population of 792 pregnant women from February 2018 to May 2020. A total of 596 women had a blood lead test: 68.5% had blood lead levels below 10 μg/L. The estimated prevalence above 25 µg/L was 4% (95% confidence interval (CI) [2.6–5.9]) and 1.3% had levels above 50 µg/L (95% CI [0.6–2.6]). Multivariate analysis showed that three risk factors significantly increased the probability of blood lead levels above 25 µg/L: the use of traditional cosmetics (adjusted odds ratio [aOR]: 3.90; 95% CI [1.65–9.21]; p = 0.002), degraded old housing (aOR: 2.67; 95% CI [1.19–6.038]; p = 0.018), and (marginally) eating bread more than twice a day (aOR: 2.40; 95% CI [0.96–6.11]; p = 0.060). Our study reveals that a three-question tool can be used to quickly screen for the risk of lead exposure in our population and to trigger lead blood tests and special vigilance during pregnancy follow-up.

Source Identification Analysis of Lead in the Blood of Japanese Children by Stable Isotope Analysis

Considering the negative effect of lead (Pb) on children's neurodevelopment, Pb exposure should be minimized to the lowest extent possible, though the blood Pb (BPb) concentrations in Japanese children are among the lowest in the world. To identify the sources of Pb in blood, isotope ratios (IRs: 207Pb/206Pb and 208Pb/206Pb) of Pb (PbIR) in whole blood from eight Japanese children were measured by multi-collector ICP mass spectrometry. Further, samples of house dust, soil, duplicate diet, and tobacco, collected from home environments, were also measured and were compared with PbIR of blood case by case. The relative contribution of Pb in the home environment to BPb were estimated by linear programming (finding an optimal solution which satisfy the combination of IRs and intakes from various sources) when appropriate. Source apportionment for three children could be estimated, and contributions of diet, soil, and house dust were 19-34%, 0-55%, and 20-76%, respectively. PbIR for the remaining five children also suggested that non-dietary sources also contributed to Pb exposure, though quantitative contributions could not be estimated. Non-dietary sources such as soil, house dust, and passive tobacco smoke are also important contributors to Pb exposure for Japanese children based on PbIR results.

Lead exposure results in defective behavior as well as alteration of gut microbiota composition in flies and their offsprings

BACKGROUND

Lead (Pb) has become one of the most dangerous metals to human health, especially to the nervous system as its persistent accumulation and high toxicity. However, how the gut microbiota influence the Pb-related neurotoxicity remains unclear. The aim of our study was to explore the link among Pb exposure, behavior changes, and gut microbiota.

METHODS

Using Drosophila melanogaster as model, climbing assay, social avoidance, social space, and short-term memory analysis were preformed to study the behavioral changes in flies exposed to Pb and their offspring. 16S rRNA sequencing was used to explore the changes in the gut microbiota of the flies with/without Pb-exposure.

RESULTS

The crawling ability, memory, and social interactions of Pb-exposed parent flies decreased significantly. For the offspring, behaviors were more significantly affected in male offspring whose male parent was exposed to Pb. The alpha diversity and the beta diversity of gut microbiota were significantly different between the Pb-exposed flies and the controls, as well as between the male offspring and the controls. Two genera, Lactobacillus and Bifidobacterium were found significantly decreased in the Pb-exposed flies when compared to the controls and significantly correlated with the learning and memory. Four genera, Bilophila, Coprococcus, Desulfovibrio, and Ruminococcus were found depleted in the female offspring of the Pb-exposed flies.

CONCLUSIONS

Lead exposure resulted in defective behavior and alteration of gut microbiota composition in flies and their offspring, alteration in gut microbiota might be the link between behavioral changes induced by Pb-exposure.

Tissue- and Sex-Specific DNA Methylation Changes in Mice Perinatally Exposed to Lead (Pb)

Lead (Pb) is a well-known toxicant that interferes with the development of a child’s nervous and metabolic systems and increases the risk of developing diseases later in life. Although studies have investigated epigenetic effects associated with Pb exposure, knowledge of genome-wide changes with in vivo low dose perinatal Pb exposure in multiple tissues is limited. Within the Toxicant Exposures and Responses by Genomic and Epigenomic Regulators of Transcription (TaRGET II) consortium, we utilized a mouse model to investigate tissue- and sex-specific DNA methylation. Dams were assigned to control or Pb-acetate water, respectively. Exposures started 2 weeks prior to mating and continued until weaning at post-natal day 21 (PND21). Liver and blood were collected from PND21 mice, and the DNA methylome was assessed using enhanced reduced representation bisulfite sequencing (ERRBS). We identified ∼1000 perinatal Pb exposure related differentially methylated cytosines (DMCs) for each tissue- and sex-specific comparison, and hundreds of tissue- and sex-specific differentially methylated regions (DMRs). Several mouse imprinted genes were differentially methylated across both tissues in males and females. Overall, our findings demonstrate that perinatal Pb exposure can induce tissue- and sex-specific DNA methylation changes and provide information for future Pb studies in humans.

Control of Lead Sources in the United States, 1970-2017: Public Health Progress and Current Challenges to Eliminating Lead Exposure

CONTEXT

During the past 45 years, exposure to lead has declined dramatically in the United States. This sustained decline is measured by blood and environmental lead levels and achieved through control of lead sources, emission reductions, federal regulations, and applied public health efforts.

OBJECTIVE

Explore regulatory factors that contributed to the decrease in exposure to lead among the US population since 1970.

DESIGN/SETTING

We present historical information about the control of lead sources and the reduction of emissions through regulatory and selected applied public health efforts, which have contributed to decreases in lead exposure in the United States. Sources of lead exposure, exposure pathways, blood lead measurements, and special populations at risk are described.

RESULTS

From 1976-1980 to 2015-2016, the geometric mean blood lead level (BLL) of the US population aged 1 to 74 years dropped from 12.8 to 0.82 μg/dL, a decline of 93.6%. Yet, an estimated 500 000 children aged 1 to 5 years have BLLs at or above the blood lead reference value of 5 μg/dL established by the Centers for Disease Control and Prevention. Low levels of exposure can lead to adverse health effects. There is no safe level of lead exposure, and child BLLs less than 10 μg/dL are known to adversely affect IQ and behavior. When the exposure source is known, approximately 95% of BLLs of 25 μg/dL or higher are work-related among US adults. Despite much progress in reducing exposure to lead in the United States, there are challenges to eliminating exposure.

CONCLUSIONS

There are future challenges, particularly from the inequitable distribution of lead hazards among some communities. Maintaining federal, state, and local capacity to identify and respond to populations at high risk can help eliminate lead exposure as a public health problem. The results of this review show that the use of strong evidence-based programs and practices, as well as regulatory authority, can help control or eliminate lead hazards before children and adults are exposed.

Epigenetic Basis of Lead-Induced Neurological Disorders

Environmental lead (Pb) exposure is closely associated with pathogenesis of a range of neurological disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), attention deficit/hyperactivity disorder (ADHD), etc. Epigenetic machinery modulates neural development and activities, while faulty epigenetic regulation contributes to the diverse forms of CNS (central nervous system) abnormalities and diseases. As a potent epigenetic modifier, lead is thought to cause neurological disorders through modulating epigenetic mechanisms. Specifically, increasing evidence linked aberrant DNA methylations, histone modifications as well as ncRNAs (non-coding RNAs) with AD cases, among which circRNA (circular RNA) stands out as a new and promising field for association studies. In 23-year-old primates with developmental lead treatment, Zawia group discovered a variety of epigenetic changes relating to AD pathogenesis. This is a direct evidence implicating epigenetic basis in lead-induced AD animals with an entire lifespan. Additionally, some epigenetic molecules associated with AD etiology were also known to respond to chronic lead exposure in comparable disease models, indicating potentially interlaced mechanisms with respect to the studied neurotoxic and pathological events. Of note, epigenetic molecules acted via globally or selectively influencing the expression of disease-related genes. Compared to AD, the association of lead exposure with other neurological disorders were primarily supported by epidemiological survey, with fewer reports connecting epigenetic regulators with lead-induced pathogenesis. Some pharmaceuticals, such as HDAC (histone deacetylase) inhibitors and DNA methylation inhibitors, were developed to deal with CNS disease by targeting epigenetic components. Still, understandings are insufficient regarding the cause–consequence relations of epigenetic factors and neurological illness. Therefore, clear evidence should be provided in future investigations to address detailed roles of novel epigenetic factors in lead-induced neurological disorders, and efforts of developing specific epigenetic therapeutics should be appraised.

Children drinking private well water have higher blood lead than those with city water

In the United States, 13% of households depend on an unregulated private well for their water. Compared with children in houses served by a regulated water utility, children in these homes have a 25% increased risk of elevated blood lead. Because lead is a neurotoxin, these children are at greater risk of experiencing irreversible cognitive damage, which can decrease their performance in school and increase their risks of behavioral problems. This study assesses associations between children’s blood lead and dependence on an unregulated private well for drinking water. It highlights the need for interventions to control lead corrosion from plumbing and well components (such as drop pipes, pump parts, and valves and fittings) in households depending on private wells.

Although the Flint, Michigan, water crisis renewed concerns about lead (Pb) in city drinking water, little attention has been paid to Pb in private wells, which provide drinking water for 13% of the US population. This study evaluates the risk of Pb exposure in children in households relying on private wells. It is based on a curated dataset of blood Pb records from 59,483 North Carolina children matched with household water source information. We analyze the dataset for statistical associations between children’s blood Pb and household drinking water source. The analysis shows that children in homes relying on private wells have 25% increased odds (95% CI 6.2 to 48%, P < 0.01) of elevated blood Pb, compared with children in houses served by a community water system that is regulated under the Safe Drinking Water Act. This increased Pb exposure is likely a result of corrosion of household plumbing and well components, because homes relying on private wells rarely treat their water to prevent corrosion. In contrast, corrosion control is required in regulated community water systems. These findings highlight the need for targeted outreach to prevent Pb exposure for the 42.5 million Americans depending on private wells for their drinking water.

New directions in understanding the role of environmental contaminants in child development: Four themes

Environmental contaminants, which include several heavy metals, persistent organic pollutants, and other harmful chemicals, impair several domains of child development. This article describes four themes from recent research on the impact of environmental contaminants on child development. The first theme, disparities in exposure, focuses on how marginalized communities are disproportionately exposed to harmful environmental contaminants. The second theme, complexity of exposures, encapsulates recent emphases on timing of exposures and mixtures of multiple exposures. The third theme, mechanisms that link exposures to outcomes, focuses on processes that elucidate how contaminants impact outcomes. The fourth theme, mitigating risks associated with exposures, sheds light on potential protective factors that could ameliorate many of the harmful effects of contaminant exposures. Developmental scientists are well positioned to contribute to interdisciplinary research that addresses these themes, which could foster additional conceptual and empirical innovations and inform policies and practices to mitigate risks and improve children's well-being.

PIG-A gene mutation as a genotoxicity biomarker in human population studies: An investigation in lead-exposed workers

The rodent Pig-a gene mutation assay has demonstrated remarkable sensitivity in identifying in vivo mutagens, while much less is known about the value of the human PIG-A assay for risk assessment. To obtain more evidence of its potential as a predictive biomarker for carcinogen exposure, we investigated PIG-A mutant frequencies (MFs), along with performing the Comet assay and micronucleus (MN) test, in 267 workers occupationally exposed to lead. Multivariate Poisson regression showed that total red blood cell PIG-A MFs were significantly higher in lead-exposed workers (10.90 ± 10.7 × 10^-6 ) than in a general population that we studied previously (5.25 ± 3.6 × 10^-6 ) (p < .0001). In contrast, there was no increase in lymphocyte MN frequency or in DNA damage as measured by percentage comet tail intensity in whole blood cells. Current year worker blood lead levels (BLL), an exposure biomarker, were elevated (232.6 ± 104.6 μg/L, median: 225.4 μg/L); a cumulative blood lead index (CBLI) also was calculated based on a combination of current and historical worker BLL data. Chi-square testing indicated that PIG-A MFs were significantly related to CBLI (p = .0249), but independent of current year BLL (p = .4276). However, % comet tail intensity and MN frequencies were better associated with current year BLL than CBLI. This study indicates that the PIG-A assay could serve as biomarker to detect the genotoxic effects of lead exposure and demonstrates that a battery of genotoxicity biomarkers having mechanistic complementarity may be useful for comprehensively monitoring human carcinogenic risk.

Lead Toxicity and Pollution in Poland

BACKGROUND

Human exposure to lead can occur in a variety of ways, all of which involve exposure to potentially toxic elements as environmental pollutants. Lead enters the body via ingestion and inhalation from sources such as soil, food, lead dust and lead in products of everyday use and in the workplace. The aim of this review is to describe the toxic effects of lead on the human body from conception to adulthood, and to review the situation regarding lead toxicity in Poland.

RESULTS

Pb is very dangerous when it is absorbed and accumulates in the main organs of the body, where it can cause a range of symptoms that vary from person to person, the time of exposure and dose. Lead in adults can cause an increase in blood pressure, slow nerve conduction, fatigue, mood swings, drowsiness, impaired concentration, fertility disorders, decreased sex drive, headaches, constipation and, in severe cases, encephalopathy or death.

CONCLUSIONS

Exposure to lead in Poland remains an important public health problem. This review will cover the range of lead exposures, from mild to heavy. Public health interventions and policies also are needed to reduce occupational and environmental exposure to this element.

Systematic Review and Meta-Analysis of the Effect of Nutrients on Blood Lead Levels in Pregnancy

OBJECTIVE

To synthesize experimental and nonexperimental research on the relationship between nutrients and blood lead levels in pregnant women. We also performed a meta-analysis on a subgroup of studies on calcium and blood lead levels.

DATA SOURCES

PubMed, Embase, and CINAHL databases were searched in July 2019.

STUDY SELECTION

We included articles published in English in any year that reported the results of experimental or observational studies on the effect of nutrients on blood lead levels in pregnancy.

DATA EXTRACTION

Three nurse reviewers extracted data and appraised the studies using tools from the Joanna Briggs Institute.

DATA SYNTHESIS AND META-ANALYSIS

We included 28 studies from 16 countries. Study authors examined 14 distinct nutrients, with calcium being the most frequent. The metaregression included nine analyses of the effect of calcium on blood lead levels and showed a small but significant inverse relationship. The quality of evidence for the effect of calcium on lead levels was high. Eleven analyses were related to the effect of iron on blood lead levels. The quality of evidence was high, and we found mostly negative associations between iron intake and blood lead levels. The quality of evidence for the remaining nutrients was moderate, with few significant findings.

CONCLUSION

Targeted nutritional interventions may be beneficial for pregnant women with current lead exposure or a history of elevated lead levels, particularly those with calcium- or iron-deficient diets. More rigorously designed studies are needed in this area.

Chronic Stress and Cardiovascular Disease among Individuals Exposed to Lead: A Pilot Study

Chronic stress and cardiovascular disease risk were explored in a predominately middle-aged adult population exposed to elevated lead levels in this cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) from the period 2007-2010. Elevated lead exposure was defined using the epidemiological threshold of a blood lead level (BLL) > 5 μg/dL as defined by the U.S. Centers for Disease Control and Prevention (CDC). Allostatic load (AL), a measure of chronic stress, was operationalized using 10 clinical markers. The geometric mean values for clinical cardiovascular disease risk markers of interest (a) Gamma glutamyl-transferase (GGT) (a marker of oxidative stress), and (b) non-HDL cholesterol (non-HDL-c) (a marker of cardiovascular disease risk) were explored among lead-exposed and less lead-exposed individuals with differential chronic stress (AL) levels. Associations between AL and GGT/non-HDL-C were analyzed using linear regression models. The likelihood of increased clinical markers in lead-exposed individuals with high compared to low AL was explored using binary logistic regression models. In analyzing lead-exposed as compared to less lead-exposed populations, the geometric mean of the variables of interest showed significant elevations among lead-exposed individuals as compared to less lead-exposed individuals. Simple linear regression revealed that AL was positively associated with the variables of interest among the lead-exposed. In binary logistic regression among the lead-exposed, those with high AL, as compared to those with low AL, had significantly higher odds of having elevated non-HDL-C. This study submits that those exposed to lead with increasing AL may experience adverse cardiovascular health outcomes.

Superfund Cleanups and Children's Lead Exposure

This study evaluates the effect of EPA's Superfund cleanup program on children's lead exposure. We linked two decades of blood lead level (BLL) measurements from children in six states with data on Superfund sites and other lead risk factors. We used quasi-experimental methods to identify the causal effect of proximity to Superfund cleanups on rates of elevated BLL. We estimated a difference-in-difference model comparing the change in elevated BLL of children closer to versus farther from lead-contaminated sites before, during, and after cleanup. We also estimated a triple difference model including children near hazardous sites with minimal to no lead contamination as a comparison group. We used spatial fixed effects and matching to minimize potential bias from unobserved differences between the treatment and comparison groups. Results indicate that Superfund cleanups lowered the risk of elevated BLL for children living within 2 kilometers of lead-contaminated sites 13 to 26 percent.