Sources, symptoms and characteristics of childhood lead poisoning: experience from a lead specialty clinic in China

Transcriptome Analysis Reveals Antioxidant Defense Mechanisms in the Silkworm Bombyx mori after Exposure to Lead

Lead (Pb) is a major source of heavy metal contamination, and poses a threat to biodiversity and human health. Elevated levels of Pb can hinder insect growth and development, leading to apoptosis via mechanisms like oxidative damage. The midgut of silkworms is the main organ exposed to heavy metals. As an economically important lepidopteran model insect in China, heavy metal-induced stress on silkworms causes considerable losses in sericulture, thereby causing substantial economic damage. This study aimed to investigate Pb-induced detoxification-related genes in the midgut of silkworms using high-throughput sequencing methods to achieve a deeper comprehension of the genes' reactions to lead exposure. This study identified 11,567 unigenes and 14,978 transcripts. A total of 1265 differentially expressed genes (DEGs) were screened, comprising 907 upregulated and 358 downregulated genes. Subsequently, Gene Ontology (GO) classification analysis revealed that the 1265 DEGs were distributed across biological processes, cellular components, and molecular functions. This suggests that the silkworm midgut may affect various organelle functions and biological processes, providing crucial clues for further exploration of DEG function. Additionally, the expression levels of 12 selected detoxification-related DEGs were validated using qRT-PCR, which confirmed the reliability of the RNA-seq results. This study not only provides new insights into the detoxification defense mechanisms of silkworms after Pb exposure, but also establishes a valuable foundation for further investigation into the molecular detoxification mechanisms in silkworms.

Lead in traditional and complementary medicine: a systematic review

Lead in the environment remains a matter of grave concern for public health. Lead has been associated with some traditional medicines and has been linked to cases of lead poisoning. A comprehensive compilation of these reports has not previously been conducted. The objective of this review is to explore how common is lead exposure after traditional medicine use, and which countries, systems and/or products are of most concern when it comes to lead contamination. A systematic search was conducted on PubMed, Ovid and EMBASE for studies published between 2005 and 2020. A grey literature search was conducted. Search terms related to lead and traditional medicine were developed for each database, and there were no limitations on language. Studies were included if they examined elevated lead in humans resulting from the use of traditional medicines reported in case reports, case-series, or observational studies. Of the papers discussing lead exposure, 85 case reports were identified and synthesized for the current review. Several themes were identified in the included studies. Traditional medicine has been used in the many parts of the world, however use is more common in South and Southeast Asian countries. The level of detectable lead in products varied widely by region and product types. Consumers of traditional medicines sought products for a wide variety of symptoms and ailments. The symptoms of lead poisoning from traditional medicine use reflected the typical symptom profile of lead poisoning, highlighting the need for awareness of traditional medicine products as a source of lead exposure. Traditional medicine usage remains an important part of health care in many regions, however there is a risk of lead exposure from several products. Health care practitioners in all regions of the world should be aware of the risk and explore the potential for traditional medicine use for patients presenting with elevated blood lead levels. Countries with a strong traditional medicine culture should explore policies for reducing lead exposure from traditional medicine products. JG, LO and MNBD are staff members of the World Health Organization. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy, or views of the World Health Organization.

Clinical case analysis of 32 children aged 0-6 years with lead poisoning in Nanning, China

Lead is one of the heavy metals that is toxic and widely distributed in the environment, and children are more sensitive to the toxic effects of lead because the blood-brain barrier and immune system are not yet well developed. The objective of the study was to investigate the clinical characteristics of lead poisoning in children aged 0∼6 years in a hospital in Guangxi, and to provide scientific basis for the prevention and treatment of lead poisoning. We collected and analyzed the clinical data of 32 children with lead poisoning admitted to a hospital in Guangxi from 2010 to 2018. The results showed that most of the 32 cases presented with hyperactivity, irritability, poor appetite, abdominal pain, diarrhea, or constipation. The hemoglobin (HGB), mean corpusular volume (MCV), mean corpuscular hemoglobin (MCH), and hematocrit (HCT) of the lead-poisoned children were all decreased to different degrees and were below normal acceptable levels. Urinary β2-microglobulin was increased. Blood lead levels (BLL) decreased significantly after intravenous injection of the lead chelator, calcium disodium edetate (CaNa2-EDTA). In addition, HGB returned to normal levels, while MCV, MCH, and HCT increased but remained below normal levels. Urinary β2-microglobulin was reduced to normal levels. Therefore, in this cohort of children, the high-risk factors for lead poisoning are mainly Chinese medicines, such as baby powder. In conclusion, lead poisoning caused neurological damage and behavioral changes in children and decreased erythrocyte parameters, leading to digestive symptoms and renal impairment, which can be attenuated by CaNa2-EDTA treatment.

Effects of food-borne cholesterol supplementation on lead-induced neurodevelopmental impairments of rats based on BDNF signaling pathway and cholesterol metabolism

Despite the ubiquity and prevalence of lead (Pb) in the environment and industry, the mechanism of lead-induced neurotoxicity in the brain remains unclear, let alone its prevention and treatment. In this study, we hypothesized that exogenous cholesterol supplementation acts as an effective remedy for lead-induced neurodevelopmental impairments caused by lead. Forty 21-day-old male rats were randomly divided into four groups and administered 0.1 % lead water and/or 2 % cholesterol-containing feed for 30 d. Ultimately, rats in the lead group lost weight, accompanied by spatial learning and memory impairments as verified by the Morris water maze test, in which the escape latency of rats was prolonged, and the number of crossings in the target platform and the residence time in the target quadrant were significantly diminished compared to the control group. Hematoxylin-Eosin (H&E) staining and Nissl staining illustrated that typical pathological morphology occurred in the brain tissue of the lead group, where the tissue structure was loose, the number of hippocampal neurons and granulosa cells decreased significantly and were arranged loosely, along with enlarged intercellular space, light matrix staining, and decline in Nissl bodies. In addition, inflammatory response and oxidative stress were significantly induced by lead. Immunofluorescence experiments showed apparent activation of astrocytes and microglia, followed by the enhancement of TNF-α and IL-β levels. Moreover, the MDA content in the lead group was elevated dramatically, whereas the activities of SOD and GSH were significantly inhibited. As for the mechanism, western blot and qRT-PCR experiments were performed, where lead could significantly inhibit the BDNF-TrkB signaling pathway, lowering the protein expression of BDNF and TrkB. Cholesterol metabolism was also affected by lead exposure, in which cholesterol metabolism-related protein expression and gene transcription, including SREBP2, HMGCR, and LDLR, were downregulated. However, cholesterol supplementation efficiently detoxified the negative effects of lead-induced neurotoxicity, reversing the inflammatory response, oxidative stress, inactivation of the BDNF signaling pathway, and imbalance of cholesterol metabolism, thus improving the learning and memory ability of rats. In brief, our study demonstrated that cholesterol supplementation could ameliorate the deficiency of learning and memory induced by lead, which is closely associated with the initiation of the BDNF/TrkB signaling pathway and regulation of cholesterol metabolism.

Amelioration of cholesterol sulfate for lead-induced CTX cell apoptosis based on BDNF signaling pathway mediated cholesterol metabolism

Lead (Pb), as a deleterious heavy metal, ubiquitously exists in environment and industry, which engenders multi-organ disfunction, especially the brain of infants who are vulnerable to attack from lead-induced neurotoxicity. Although cholesterol sulfate (CS) is crucial constituent of cell membranes and precursor of neurosteroids, which maintains the function and survival of neurons, the role of CS in lead-induced neurological damage still remains incomplete. In this work, Rat Brain Astrocytes cell line (CTX cells) was applied into exploration that protective effects of CS on CTX cell apoptosis induced by lead via the regulation of BDNF/TrkB signaling pathway mediated cholesterol metabolism. We found that CTX cells exposed to lead manifested apparent cytotoxicity, where the viability of CTX cells was significantly suppressed, accompanied with the elevation of apoptosis, in response to a trend towards increases in reactive oxygen species (ROS) production and pro-apoptotic protein Cleaved-caspase3, synchronized with the decline in anti-apoptotic protein Bcl-2. Moreover, accumulation of lead in CTX cells showed a dose-dependent increase, and meanwhile, decrements in cholesterol content occurred along with increase in lead exposure, in which expressions of cholesterol metabolism related proteins and transcriptions of its genes (SREBP2, LDLR, and HMGCR) were diminished. Furthermore, BDNF signaling pathway was obviously blocked after lead exposure, down-regulating expressions of proteins BDNF and TrkB. However, pretreatment with CS detoxified the negative impacts of lead-invoked CTX cell damage, acting as an effective remedy for apoptosis, imbalance of cholesterol metabolism and inhibition of BDNF signaling pathway. In addition, the relationship between BDNF signaling pathway and cholesterol metabolism was further verified, in which cholesterol metabolism related proteins and genes were promoted significantly after the activation of BDNF/TrkB signaling pathway using 7,8-Dihydroxyflavone (7,8-DHF), thereby detoxifying lead-induced CTX cell injury. However, the pretreatment of TrkB inhibitor ANA-12 offset the promotion of 7,8-DHF and ultimately inhibit cholesterol metabolism. Overall, our study demonstrated that CS could initiate the BDNF/TrkB signaling pathway, regulating the cholesterol metabolism against CTX cell apoptosis invoked by lead.

Source apportionment based on lead isotope ratios: Could domestic dog's blood lead be used to identify the level and sources of lead pollution in children?

Domestic dogs have been proved to be used as "sentinel organisms" to monitor human lead exposure. However, whether dogs' blood can be used to identify the levels and pollution source of children's lead exposure still needs evidence. To evaluate the potential use of domestic dogs' blood lead as an indicator of lead exposure levels and pollution source of children, accompanying with potential environmental media samples, lead concentrations and isotope ratios (expressed as ²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb) in blood were investigated and compared between children and dogs, who came from a Pb-Zn smelter area, a coal fired area and a control area without industrial activity. The results showed that there were significant correlations in blood lead levels (BLLs) between children and dogs in the study areas (p < 0.01). The lead isotope ratios (LIRs) in blood of children and dogs were disparate among the three areas, however, the LIRs of dogs were quite correlated with those of children in each area (p < 0.01). With the comparison of LIRs between potential pollution sources (slag, ore, coal, paint) and blood samples, the identified lead sources based on dogs' blood were found to be coincident with those based on children's blood. Ore smelting and coal combustion were the main sources of lead exposure for the dogs and children in the smelting area, and coal combustion was the predominant source for the children and dogs living in the coal burning area and control area. The results showed that dogs' BLLs might be used to estimate children's BLLs, and blood LIRs measurements of dogs' could be used as an alternative for identifying the sources of children's lead exposure. This study further provided relevant evidence for dogs to be sentinels exposed to human lead exposure and an alternative method for source apportionment of children's lead exposure.

Childhood lead exposure and sex-based neurobehavioral functioning in adolescence

It is well documented that childhood lead exposure is associated with long-term decreases in intelligence quotients (IQ). Lesser known is the relationship with neurobehavioral domains, especially in adolescence. This study sought to identify cross-sectional and longitudinal associations between lead exposure and adolescent executive and visual-motor functioning and examine sex-based differences. Participants were 681 children from Jintan, China who had their blood lead levels (BLLs) assessed at age 3-5 years and 12 years old and neurobehavioral functioning assessed through the University of Pennsylvania Computerized Neurocognitive Battery (PennCNB) platform http://www.med.upenn.edu/bbl at 12 years old. Mean BLLs were 6.41 mcg/dl at age 3-5 years and 3.10 mcg/dl at 12. BLLs at 3-5 years and 12 years were used as predictors for the individual neurobehavioral domains in general linear models while controlling for father and mother occupation and education, residence location, age, and adolescent IQ. Models were run separately for males and females. In adjusted models, males BLLs at 3-5 years were associated with increased time to correctly complete tasks in multiple domains including abstraction/flexibility (β = 19.90, 95% CI( 4.26, 35.54) and spatial processing (β = 96.00, 95% CI 6.18, 185.82) at 12 years. For females in adjusted models, BLLs at 3-5 years were associated with increasing time to correctly complete tasks on the episodic memory domain task (β = 34.59, 95% CI 5.33, 63.84) at 12 years. Two adolescent cross-sectional relationships remained in the adjusted models for males only, suggesting a positive association between BLLs and increasing time for correct responses on the attentional domain task (β = 15.08, 95% CI 0.65, 29.51) and decreasing time for correct responses on the episodic memory task (β = -73.49, 95% CI -138.91, -8.06) in males at 12 years. These associations remained with and without controlling for IQ. These results suggest that lead exposure is associated with overall deficits in male and female neurobehavioral functioning, though in different domains and different timing of exposure.

GO/TiO2-Related Nanocomposites as Photocatalysts for Pollutant Removal in Wastewater Treatment

Water pollution has been a prevalent issue globally for some time. Some pollutants are released into the water system without treatment, making the water not suitable for consumption. This problem may lead to more grave problems in the future including the destruction of the ecosystem along with the organisms inhabiting it, and illness and diseases endangering human health. Conventional methods have been implemented to remove hazardous pollutants such as dyes, heavy metals, and oil but are incapable of doing so due to economic restraints and the inability to degrade the pollutants, leading to secondary pollution. Photocatalysis is a more recently applied concept and is proven to be able to completely remove and degrade pollutants into simpler organic compounds. Titanium dioxide (TiO₂) is a fine example of a photocatalyst owing to its cost-effectiveness and superb efficiency. However, issues such as the high recombination rate of photogenerated electrons along with positive holes while being only limited to UV irradiation need to be addressed. Carbonaceous materials such as graphene oxide (GO) can overcome such issues by reducing the recombination rate and providing a platform for adsorption accompanied by photocatalytic degradation of TiO₂. The history and development of the synthesis of GO will be discussed, followed by the methods used for GO/TiO₂ synthesis. The hybrid of GO/TiO₂ as a photocatalyst has received some attention in the application of wastewater treatment due to its efficiency and it being environmentally benign. This review paper thereby aims to identify the origins of different pollutants followed by the sickness they may potentially inflict. Recent findings, including that GO/TiO₂-related nanocomposites can remove pollutants from the water system, and on the photodegradation mechanism for pollutants including aromatic dyes, heavy metal and crude oil, will be briefly discussed in this review. Moreover, several crucial factors that affect the performance of photocatalysis in pollutant removal will be discussed as well. Therefore, this paper presents a critical review of recent achievements in the use of GO/TiO₂-related nanocomposites and photocatalysis for removing various pollutants in wastewater treatment.

Association between lead source exposure and blood lead levels in some lead manufacturing countries: A systematic review and meta-analysis

Lead is one of the 10 most toxic chemicals of greatest concern for its effects on public health. Predominantly, in undeveloped countries, high blood lead levels (BLLs) persist in the population. To develop intervention strategies that may reduce lead exposure in populations, it is a priority to know the sources of lead pollution. The objective of this critical review and meta-analysis is to assess whether there is an association between different sources of lead exposure and the mean difference in blood lead levels in people exposed. To identify the major lead source exposure, a statistical analysis was performed on selection studies. This investigation reveals the limited information available on the sources of lead in Mexico and other lead producer countries, such as Croatia, Ecuador, Brazil, South Korea, India, Nigeria, Turkey, and China. Meta-analysis could be performed only in battery, smelting mining, and glazed ceramic workers. Battery manufacturing workers have the highest mean difference level of lead in their blood worldwide. Mexico has the second highest mean difference BLL in battery workers in the world. An interesting difference between the mean difference in BLL in mining workers from uncontrolled industry (-39.38) and controlled industry (-5.68) was found. This difference highlighted the success of applying strict control of lead sources and community education to reduce BLL and its potential harmful effects on human health and the environment. Children living near mining sites have the highest mean difference BLL (-11.1). This analysis may aid in assessing the source of lead exposure associated with a range of BLLs in people. Furthermore, this review highlights several social and cultural patterns associated with lead exposure and lead levels in control populations. These results could help to develop international lead regulations and appropriate public health guidelines to protect people around the world.

Blood lead concentrations among pediatric patients with abdominal pain: a prospective cross-sectional study

Background

Lead exposure is one of the most menacing of environmental exposures, particularly in children. Children are more susceptible to the effects of lead which manifest in many organ systems, including interference with mental and motor development. Lead poisoning can cause colicky abdominal pain. In this study, the authors sought to evaluate the prevalence of elevated blood lead level (BLL) and its contributing factors among pediatric patients presenting with abdominal pain. An epidemic of lead poisoning in adults was previously uncovered, and thus a concern for pediatric lead poisoning was raised.

Methods

Pediatric patients presenting to two pediatric clinics in Tehran with abdominal pain were eligible for enrollment in a descriptive prospective cross-sectional study. A predesigned questionnaire was filled for each patient by their consenting parents. The questionnaire queried demographic information, environmental, social, and other relevant parameters for lead exposure. After completion of the questionnaire, biometrics were obtained, and a blood sample was taken from each patient for measurement of BLL and complete blood count.

Results

A total of 187 patients were enrolled in the study. Of them, almost 20% had BLL ≥ 5 µg/dL. Univariate analysis showed that age (p = 0.002, OR 3.194, CI 95% 1.504–6.783), weight (p = 0.009, OR 2.817, CI 95% 1.266–6.269), height (p = 0.003, OR 3.155, CI 95% 1.443–6.899), and playing with both plastic and cotton toys (p = 0.03, OR 2.796, CI 95% 1.072–7.295) were significant predictors of high BLLs. Maternal level of education correlated with blood lead concentrations (p = 0.048, OR 2.524, CI 95% 1.006–6.331).

Conclusions

A clinically significant number of cases of abdominal pain may have high BLLs. Specific attention should be paid to children presenting with abdominal pain, especially due to the detrimental effects of lead on their mental and motor development.

In-depth transcriptome unveils the cadmium toxicology and a novel metallothionein in silkworm

Heavy metal pollution has gradually become a major global issue. It is so far reaching in part because heavy metals are absorbed by soil and affect almost all species via ecological cycles. Silkworms (Bombyx mori) are poisoned by heavy metals through a soil-mulberry-silkworm system, which inhibits larval growth and development and leads to a decrease in silk production. In the present study, we performed transcriptome sequencing of larval midgut with cadmium exposure to explore the toxicological mechanism of heavy metal, and found that the following potential pathways may be involved in cadmium infiltration: endocytosis, oxidative phosphorylation, and MAPK signaling. Moreover, we identified a novel metallothionein in silkworm, which is inhibited by cadmium exposure and able to improve heavy metal tolerance in B. mori cell lines and Escherichia coli. We also generated a transgenic silkworm strain overexpressing metallothionein and the result showed that metallothionein observably enhanced larval viability under cadmium exposure. This study used RNA sequencing to reveal a mechanism for cadmium toxicology, and identified and functionally verified BmMT, offering a new potential heavy metal-tolerant silkworm variety.

Biomonitoring of Lead Exposure in Children from Two Fishing Communities at Northern Colombia

Lead (Pb) exposure is a growing concern in developing countries, especially in vulnerable children. The objective of this study was to evaluate blood lead levels (BLL) in children from two fishing populations at Northern Colombia, Loma de Arena and Tierrabomba, as well as their association with morphometric parameters, markers of hematological status, liver function, and mRNA expression of genes related to Pb toxicity. A total of 198 blood samples were collected from participants aged 5-16 years old. The mean (± standard error) BLL for the studied sample was 3.6 ± 0.3 μg/dL, and the 97.5th percentile was 21.0 μg/dL. The participants of Loma de Arena and Tierrabomba presented BLL of 3.9 ± 0.5 and 2.9 ± 0.3 μg/dL, respectively. Children born preterm had greater BLL than those born at full term. Boys had greater BLL than girls, which also occurred for participants between 12 and 16 years old, compared with those aged 5-11 years old. The BLL were negatively correlated with body mass index in children from Loma de Arena, but an opposite behavior was observed for Tierrabomba. In Loma de Arena, the mRNA expression of interferon gamma, a pro-inflammatory cytokine, increased with the BLL, but that of δ-aminolevulinic acid dehydrogenase, a sensor for Pb poisoning, decreased. In Tierrabomba, gene expression did not change with BLL. These results show that in fishing communities, lead exposure promotes different health impacts depending on age, sex, and other site-specific factors. In any case, appropriate educational and intervention programs should be carried out to minimize Pb exposure in children.

Adverse health effects of lead exposure on physical growth, erythrocyte parameters and school performances for school-aged children in eastern China

We conducted a cross-sectional study with 395 completely matched student samples enrolled from a public primary school in Nanjing of eastern China, including questionnaires, blood samples, growth indexes and school performances, all of which were used for the analysis of variance (ANOVA) and general linear model (GLM). The results showed that factors, such as gender, age, parents' education, residential passive smoking and picky eaters, had significant impacts on the blood lead levels (BPbs). As for the linear and non-linear dose-response relationship between BPbs and erythrocyte parameters, we found a positive association between BPbs and red blood cell count (RBC count) and mean corpuscular hemoglobin concentration (MCHC) but a negative association between BPbs and hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH). When BPbs increased by 10 μg/L, the RBC count increased by 0.18 × 10¹²/L, while HGB and HCT decreased by 1.19 g/L and 0.41% for boys, respectively. As for girls, corresponding increases in RBC count was 0.05 × 10¹²/L, while HGB and HCT decreased by 0.82 g/L and 0.23%. Meanwhile, for both boys and girls, MCHC increased by 2.55 g/L, while MCV and MCH levels decreased by 0.41 fL and 0.12 pg each. Furthermore, a remarkable adverse effect (p < 0.05) was observed on children's school performances as a result of increased BPbs. As BPbs increased by 10 μg/L, children's scores for Chinese, Math and English decreased by 0.42 points, 0.39 points and 0.87 points, respectively. In summary, our study indicated that lead exposure can have adverse health effects on children's erythrocyte parameters, BMI, and school performances.

Impact of Lead Exposure on Thyroid Status and IQ Performance among School-age Children Living Nearby a Lead-Zinc Mine in China

BACKGROUND

Lead exposure is one of the most concerning public health problems worldwide, particularly among children. Yet the impact of chronic lead exposure on the thyroid status and related intelligence quotient performance among school-age children remained elusive.

OBJECTIVE

The aim of this study was to evaluate the influence of lead exposure on the thyroid hormones, amino acid neurotransmitters balances, and intelligence quotient (IQ) among school-age children living nearby a lead-zinc mining site. Other factors such as rice lead levels, mothers' smoking behavior, and diet intake were also investigated.

METHODS

A total of 255 children aged 7-12 years old were recruited in this study. Blood lead level (BLL), thyroid hormones including free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH), and amino acid neurotransmitters such as glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) were measured using graphite furnace atomic absorption spectroscopy (GFAAS), chemiluminescence immunoassay, high performance liquid chromatography (HPLC). Raven's standard progressive matrices (SPM) and the questionnaire were used to determine IQ and collect related influence factors.

RESULTS

The average BLL of children was 84.8 μg/L. The occurrence of lead intoxication (defined as the BLL ≥ 100 μg/L) was 31.8%. Serum TSH levels and IQ of lead-intoxicated children were significantly lower than those without lead toxicity. The GABA level of girls with the lead intoxication was higher than those with no lead-exposed group. Correlation analyses revealed that BLL were inversely associated with the serum TSH levels (R= -0.186, p < 0.05), but positively related with IQ grades (R = 0.147, p < 0.05). Moreover, BLL and Glu were inversely correlated with IQ. In addition, this study revealed four factors that may contribute to the incidence of lead intoxication among children, including the frequency of mother smoking (OR = 3.587, p < 0.05) and drinking un-boiled stagnant tap water (OR = 3.716, p < 0.05); eating fresh fruits and vegetables (OR = 0.323, p < 0.05) and soy products regularly (OR = 0.181, p < 0.05) may protect against lead intoxication.

CONCLUSION

Lead exposure affects the serum TSH, GABA levels and IQ of school-aged children. Developing good living habits, improving environment, increasing the intake of high-quality protein and fresh vegetable and fruit may improve the condition of lead intoxication.

Childhood lead poisoning from domestic products in China: A case study with implications for practice, education, and policy

OBJECTIVE

This study aimed to report three representative childhood lead poisoning cases in China from domestic products exposure and to highlight their critical implications for practice, education, and policy in prevention and treatment of childhood lead poisoning by health care providers, especially public health nurses.

DESIGN AND SAMPLE

Three representative childhood lead poisoning cases occurring in 2017 were collected and analyzed.

RESULTS

The lead exposure sources of three cases were evaluated by experts in the field and determined to be tin pots, home factories for tinfoil, and contamination of folk medicine, respectively. These cases demonstrated that the lack of lead exposure risk assessment, insufficient knowledge of potential lead exposure sources, underdeveloped policy, and regulations were areas for improvement.

CONCLUSIONS

The best strategies for preventing lead poisoning include an appropriate risk assessment of lead exposure, implementation of comprehensive parental health education, conduction of further research by public health providers, and the application of policy strategies by the government. It was determined that public health nurses are at the frontline of prevention of lead poisoning in children.

Potential dietary factors for reducing lead burden of Chinese preschool children

Dietary approaches to treat children's low lead exposure are implemented routinely in China, while evidence for the effect could not be provided until now. The aim of this study was to examine the relationship between diets including nutrition supplementation and blood lead level of preschool children of China. In total, 17,859 preschool children from 14 cities were recruited, and their social-demography, living environment, and dietary intakes were collected, and capillary blood sample was tested for lead concentration. The average blood lead concentration was 34.5 μg/L, and after adjusting children's social-demography factors, the consumption of milk or dairy production, fruits, and calcium supplementation had negative dose-response relationships with blood lead level. Conversely, intake of iron-rich food and supplementation was not associated. Further studies are needed to prove the causal relationships.

Blood lead, bone lead and child attention-deficit-hyperactivity-disorder-like behavior

BACKGROUND AND OBJECTIVE

Mounting evidence showed that lead exposure increased the risk of child attention-deficit-hyperactivity disorder (ADHD). Epidemiologic studies have typically used the blood-lead as a biomarker of lead exposure; blood-lead levels mostly reflect recent lead exposure. However, few studies have examined the relationship between bone-lead, a biomarker of cumulative exposure, and ADHD. Therefore, we aimed to compare the associations of bone-lead vs blood-lead levels with child ADHD symptoms and comorbidities.

METHODS

A total of 164 children aged 3-15 years were enrolled during 2014-2015. The Vanderbilt-ADHD-Diagnostic-Parent-Rating Scale (VADPRS) was used to evaluate the children's ADHD symptoms and comorbidities. Children's blood and bone lead concentrations were assessed, the latter using a non-invasive K-X-ray-fluorescence technique. According to blood-lead levels, children were classified into high (blood-lead ≥ 10.0 μg/dL) and low (blood-lead < 10.0 μg/dL) blood-lead groups. According to bone-lead levels, children were classified into high (bone-lead ≥ 2.66 μg/g) and low (bone-lead < 2.66 μg/g) bone-lead groups. We associated blood/bone lead with VADPRS data using multi-variable binary logistic regression models.

RESULTS

Children in the high blood-lead group had higher hyperactivity/impulsivity (P = 0.02) scores than the corresponding low blood-lead group. Children in the high bone-lead group had higher hyperactivity/impulsivity (P = 0.02) and oppositional-defiant-disorder (ODD) (P = 0.03) scores than the corresponding low bone-lead group. After adjusting for relevant confounders, children in the high bone-lead group were more likely to have ODD-behavior than the low group (OR = 6.7, 95%CI: 1.2-36.5). However, no adjusted association was observed between blood-lead and any ADHD-domain score.

CONCLUSION

High levels of cumulative lead exposure in children may be an independent risk factor of ODD-behavior.