Blood Lead Levels In Children Research Articles

Improving Equitability and Inclusion for Testing and Detection of Lead Poisoning in US Children.

Policy Points Child lead poisoning is associated with socioeconomic inequity and perpetuates health inequality. Methods for testing and detection of child lead poisoning are ill suited to the current demographics and characteristics of the problem. A three-pronged revision of current testing approaches is suggested. Employing the suggested revisions can immediately increase our national capacity for equitable, inclusive testing and detection. ABSTRACT: Child lead poisoning, the longest-standing child public health epidemic in US history, is associated with socioeconomic inequity and perpetuates health inequality. Removing lead from children's environments ("primary prevention") is and must remain the definitive solution for ending child lead poisoning. Until that goal can be realized, protecting children's health necessarily depends on the adequacy of our methods for testing and detection. Current methods for testing and detection, however, are no longer suited to the demographics and magnitude of the problem. We discuss the potential deployment and feasibility of a three-pronged revision of current practices including: 1) acceptance of capillary samples for final determination of lead poisoning, with electronic documentation of "clean" collection methods submitted by workers who complete simple Centers for Disease Control and Prevention-endorsed online training and certification for capillary sample collection; 2) new guidance specifying the analysis of capillary samples by inductively coupled plasma mass spectrometry or graphite furnace atomic absorption spectrometry with documented limit of detection ≤0.2 μg/dL; and 3) adaptive "census tract-specific" universal testing and monitoring guidance for children from birth to 10 years of age. These testing modifications can bring child blood lead level (BLL) testing into homes and communities, immediately increasing our national capacity for inclusive and equitable detection and monitoring of dangerous lower-range BLLs in US children.

Leaded aviation gasoline exposure risk and child blood lead levels.

Lead-formulated aviation gasoline (avgas) is the primary source of lead emissions in the United States today, consumed by over 170,000 piston-engine aircraft (PEA). The U.S. Environmental Protection Agency (EPA) estimates that four million people reside within 500m of a PEA-servicing airport. The disposition of avgas around such airports may be an independent source of child lead exposure. We analyze over 14,000 blood lead samples of children (≤5y of age) residing near one such airport-Reid-Hillview Airport (RHV) in Santa Clara County, California. Across an ensemble of tests, we find that the blood lead levels (BLLs) of sampled children increase in proximity to RHV, are higher among children east and predominantly downwind of the airport, and increase with the volume of PEA traffic and quantities of avgas sold at the airport. The BLLs of airport-proximate children are especially responsive to an increase in PEA traffic, increasing by about 0.72 μg/dL under periods of maximum PEA traffic. We also observe a significant reduction in child BLLs from a series of pandemic-related interventions in Santa Clara County that contracted PEA traffic at the airport. Finally, we find that children's BLLs increase with measured concentrations of atmospheric lead at the airport. In support of the scientific adjudication of the EPAs recently announced endangerment finding, this in-depth case study indicates that the deposition of avgas significantly elevates the BLLs of at-risk children.

Comparison of Blood Lead Levels in Children and Adolescents with and without Functional Abdominal Pain.

Functional abdominal pain is a health concern with chronic abdominal discomfort without clear etiology. Several etiologic factors are raised in this regard, one related to environmental factors. This study aimed to compare blood lead levels between children and adolescents with and without functional abdominal pain. This case-control study was performed in 2019-2020 in Isfahan, Iran. The sample size was calculated as 70 cases and an equal number of controls. Cases were children and adolescents with functional gastrointestinal disorder (FGID), and controls were grouped age- and sex-matched. Controls were randomly selected from those referred for routine health screening. Both groups obtained blood lead, iron, and calcium levels. All participants completed the FFQ Food Consumption and Environmental Pollutants Questionnaire. Participants were 139 children (68 cases and 71 controls). The mean (SD) age was 9.40 (3.91) years in the FGID group and 8.79 (3.46) years in the controls (P = 0.330). The mean (SD) blood lead level was not significantly different between the FGID group and the controls (3.98 ± 2.56 vs 3.81 ± 1.96 μg/dl, respectively, P = 0.670). We found that 55.3% of children with high lead levels had FGID, while 44.4% of children with lower lead levels had FGID, but the difference was not statistically significant (P = 0.33). We found that the lead level was higher in patients with FGID than in the controls; however, this difference was not significantly different. This might be because of elevated lead levels in both groups. Future ecological studies with a large sample size are necessary in this regard.

An interdisciplinary team-based approach for significantly reducing lower-level lead poisoning in U.S. children.

Twenty-one families with 49 children, were offered enrollment when at least 1 child in the family was found to have a BLL >2.5µg/dL. Child BLLs, determined by ICPMS, were monitored at 4- to 6-month intervals. Education was tailored to family needs, reinforced through repeated parent engagement, and was followed by home testing reports with detailed case-specific information and recommendations for no-cost/low-cost mitigation. Ninety percent of enrolled families complied with the mitigation program. In most cases, isolated, simple-to-mitigate lead hazard sources were found. Most prevalent were consumer products, found in 69% (11/16) of homes. Lead paint was identified in 56% (9/16) of homes. Generalized linear regression with Test Wave as a random effect showed that children's BLLs decreased significantly following the intervention despite fluctuations. Lower-level lead poisoning can be reduced through an interdisciplinary approach that combines ongoing child BLL monitoring; repeated, one-on-one parent prevention education; and identification and no-cost/low-cost mitigation of home lead hazards. Biannual child BLL monitoring is essential for detecting and responding to changes in child BLLs, particularly in neighborhoods deemed high-risk for child lead poisoning.

Nine kinds of novel cytokines identified in children with lead exposure

Lead (Pb) is a neurotoxic heavy metal element with many recognized adverse health side effects, and its main target of lead toxicity is the central nervous system. The mechanism of lead toxicity is still uncertain. However, there are few studies investigated the cytokines changes caused by lead exposure in children. The BLLs was quantified using flame atomic absorption spectroscopy. The novel cytokines were detected by RayBio@ Human Cytokine Antibody Array. A total of 4 children with elevated blood lead levels (BLLs) and 4 children with low BLLs were chosen in the study. Volcano plot analysis was performed to identify significant proteins, with the criteria: P value <0.05 and log2 fold change >1. The mean BLLs of children with elevated BLLs (5.675±1.018 μg/dL) has significant difference compared with those with low BLLs (1.975±0.3966 μg/dL) (P=0.0148, t=3.385). And 9 kinds of novel cytokines were identified. The expression of IL-6, IL-8 and IL-17 was significantly up-regulated, while the expression of BDNF, BMP-4, IGF-1, IL-7, IL-10 and Leptin was significantly down-regulated.

Searching the Blood Lead Level in Children with Attention Deficit Hyperactivity Disorder: A Case-control Study in Tehran, Iran

Background: Attention deficit hyperactivity disorder (ADHD) is a common behavioral problem in children. Identifying the associated risk factors of ADHD is very important for the prognosis and early diagnosis of the disease. Here, we evaluated the association between lead exposure and growth indexes in children with ADHD. Materials and Methods: This case-control study was conducted on 30 children with ADHD and 50 healthy subjects. The patient’s age was between 5-12 years. Demographic and clinical information of children were recorded. Blood lead levels were measured in all samples by atomic absorption spectrometry. Results: Children with ADHD had significantly higher mean BMI than the control group (16.54 ± 2.8 kg/m2 vs. 14.82 ± 1.68 kg/m2; p=0.001). The mean of blood lead in children with ADHD was significantly higher than the normal group (10.58 ± 8.06 μg/dl vs. 7.52 ± 2.26 μg/dl; p=0.01). Multiple logistic analysis revealed one unit increase in BMI was associated with a higher risk of ADHD by 1.5 times (P=0.005; OR = 1.50), while one unit increase in blood lead level increased the risk of ADHD by 1.15 times (P=0.03, OR=1.15). Conclusion: Higher BMI and blood lead concentration are risk factors for ADHD among Iranian children.

Relationship Between Primary Language Spoken at Home and Blood Lead Levels in Children from Northeast Ohio, United States: A Retrospective Cohort Study.

To estimate the prevalence and incidence of blood lead levels (BLL) ≥ 5 and ≥ 3.5µg/dl and assess their association with primary language spoken at home in Northeast Ohio, U.S. children, a retrospective cohort study was conducted among 19,753 children aged < 6years. Primary language spoken at home was used to define children fromresettled refugee families (RRFs) and non-RRFs. The overall BLL ≥ 5 and ≥ 3.5µg/dl prevalence were 3.22 and 6.10%, and incidence rateswere 2.25 and 3.64 cases per 100 person-years, respectively. Compared to children from non-RRFschildren from RRFs were 3.62-times [95% confidence interval (CI): 1.84, 7.13] as likely to have BLL ≥ 5µg/dl prevalence, and 6.72-times [95% CI 2.60, 17.40] as likely to have BLL ≥ 5µg/dl incidence during the follow-up period. The higher prevalence and incidence of BLL acquired in the United States among children from RRFs warrant further research to identify specific environmental and sociocultural lead sources for these children.

Geospatial analysis of patients' social determinants of health for health systems science and disparity research.

Geospatial analysis of patients' social determinants of health for health systems science and disparity research.

Community Health Services and Blood Lead Reduction in Children

Objectives: To assess the effect of multidisciplinary community health services on reducing blood lead in children. Material and methods: Retrospective observational study, before-after type. The information of an intervention program in the “Mi Peru” district was analyzed. The population consisted of 1,191 children of both genders who had results of blood lead level and who were evaluated during 2016 and 2017. The sample consisted of 187 children with blood lead levels ≥10 μg/dL. Community health services had three components: comprehensive multidisciplinary care, health education and house calls. Results: The blood lead level at the start of the intervention, 88.5% (n=139) belonged to category II and 11.5% (n=18) belonged to category III. At the end of the intervention, 66.9% (n=105) resulted in category I, the proportion of lead levels belonging to categories II and III was reduced to 29.9% (n=47) and 3.2% (n=5) respectively. In relation to the blood lead level at the beginning of the intervention and at the end of the intervention, the initial mean of 13.96 μg/dL was reduced to 8.96 μg/dL and the median from 12.40 μg/dL to 8.20 μg/dL (p<0.001). Conclusions: Community health services reduced blood lead levels in children with elevated blood lead levels. It is suggested to promote and strengthen the comprehensive house calls and health education about the risks of lead exposure.

Lead exposure from general aviation emissions in the UK: A review and call for action

AbstractLeaded fuel emissions exposed a global population of children to lead and its profound health consequences. Recognition of its harms precipitated a global phase out and replacement with unleaded substitutes for road vehicles. Despite this widespread recognition and action, aviation fuel for piston engine aircraft still contains lead. Leaded aviation fuel (AVGAS100LL) contains 0.56 g of tetraethyl lead (TEL) per litre and this lead must be jettisoned from the engine during operation to prevent fouling. This action distributes lead and lead compounds into the air and soil around general aviation airports. This has been shown to increase the blood lead levels (BLLs) of children living nearby to clinically significant levels. Whilst this problem is recognised by the EPA in the United States, it has received little attention in the United Kingdom. We provide a review of the situation in the United Kingdom with regard to the current policy and regulation framework. We analysed the UK's general aviation airport fleet, general avation airport data and GB residential address data. We estimate the unleaded‐readiness of the UK aviation fleet and the current usage of fuels at UK general aviation airports. We provide a first‐order estimate of the number of residential addresses exposed to lead near general aviation airports. We find that the majority of aviation fuel sold in the United Kingdom is leaded and that there are 370,632 residences within 4 km of a general aviation airport at risk from exposure to lead emissions. Finally, we present a path forward for regulation change and public health monitoring.

The relationship between childhood blood lead levels below 5µg/dL and childhood intelligence quotient (IQ): Protocol for a systematic review and meta-analysis.

The causal association between childhood lead (Pb) exposure and decrements in intelligence quotient (IQ) is well-established, and no safe blood lead level (BLL) in children has been identified. An international pooled analysis of seven prospective studies published by Lanphear et al. in 2005 quantified the relationship between childhood BLL and IQ. Further studies of Pb and IQ have been published more recently with mean BLLs generally lower than in the studies analyzed by Lanphear et al. In this article, we present the protocol for a systematic review to estimate an updated Pb-IQ relationship focusing on BLLs below 5µg per deciliter (µg/dL). What is the quantitative relationship between childhood BLLs and IQ at ages 3-17years at BLLs below 5μg/dL? A comprehensive search of the scientific literature will utilize citation mapping and key word searching. In the citation mapping approach, we will identify seed references that are relevant to our study question, and will then identify more recent references that have cited at least one of the seed references. The key word search will be conducted in the PubMed, Biosis Previews, Scopus, and Web of Science databases. We will also search electronic grey literature databases for conference proceedings, dissertations, and preprints. We will include studies that measured BLL in children at any age, assessed full-scale IQ of the same children (concurrent with or subsequent to BLL sample collection) at ages 3-17, and estimated a continuous quantitative relationship between BLL and IQ. We will consider only studies with a central tendency BLL<10µg/dL. The title and abstract of each record will be reviewed independently by two authors to determine whether the study in question satisfies the inclusion criteria. The full text of each article remaining after title-abstract screening will be reviewed independently by two authors to determine whether the study in question satisfies the inclusion criteria. Two authors will independently extract study characteristics and data from each included study. Studies meeting inclusion criteria will be evaluated for risk of bias (RoB) using the Navigation Guide method applied in a previous systematic review of neurodevelopmental effects (Lam et al., 2017), with adaptation to our study question. Each study will be independently evaluated by two review authors. We intend to conduct a random-effects meta-analysis to summarize the effects of children's exposure to Pb on IQ scores. Additionally, we plan to perform sensitivity analyses using sub-group analyses and/or meta-regression techniques to assess the impact of study design and study population characteristics to examine potential heterogeneity of results across studies. We will assign a confidence level rating (high, moderate, low, or very low) to the effect estimate from the meta-analyses/meta-regressions.

Spatiotemporal variation in the blood lead levels of Chinese children with the environmental Kuznets curve trend

The environmental Kuznets curve (EKC) is often used to analyze the relationship between environmental pollution health indicators and economic development level in different regions. In developed countries, the blood lead levels (BLLs) of children have been declining fitting the EKC since the 1970s. However, such figures in China have remained at relatively high levels, without any obvious decline, since 2010. We explored spatial variations and graded countermeasures using reported data on BLLs including the lead poisoning rates (LPRs) of children. We found that there were prefectures where either the mean BLLs of the children had reached 100.00 μg/L or the LPRs of more than 40% of the children had reached 100 μg/L. When we reduced the average BLLs to 50 μg/L or lowered the proportion of children with a lead poisoning rate (LPR) above 100 μg/L to 10.00%, the EKC trend decreased, and the linear slope after 2010 became -0.202. If the areas where children's BLLs exceeded 50.00 μg/L or the proportion of children with an LPR above 100 μg/L was more than 10.00% will be controlled, the linear slope of the EKC decrease trend after 2010 will became -0.989, and the national average of children's BLLs would decline by 22.17%. The study concluded that children's BLLs in different regions of China are situated at different EKC stages, and urgent prevention and control strategies must be put in place for undeveloped areas.

Environmental chemical risk factors of breast cancer in Nigeria III: Metal: Lead

Lead (Pb) is a metalloestrogen and a notable breast cancer risk factor. Lead is an International Agency for Research on Cancer (IARC) group 2A carcinogen. There is no level of exposure to lead that is known to be without harmful effects. Nigeria has literally every known environmental risk factor for lead exposure. Notable sources of lead exposure in Nigeria are lead in contaminated water, paints, artisanal gold ore processing, incineration of lead-containing waste and electronic waste (e-waste). Other sources of lead exposure are ‘tiro’—a lead-laden eye cosmetic, smoked fish particularly those displayed near highways with high vehicular traffic density, vegetables and root crops grown in mining communities, fruit exposed to lead-laden ripening agents, “Calabar chalk”—a lead-laden pica mostly consumed by pregnant women, and children’s toys. Prenatal vitamins supplements, paediatric medication syrups, traditional alcoholic and non-alcoholic drinks such as Kunnu and Zobo were also found as notable sources of lead consumption. Studies in Nigeria on blood lead (Pb) levels in children, pregnant women, and breast milk of nursing women were found to contain high lead levels. Lead exposure is preventable. Hitherto, the neurotoxicity of lead has been the dominant concern as regards lead exposure in children. The breast cancer risk factor now reinforces the zero tolerance for lead exposure.

Prevalence of elevated blood lead levels and risk factors among children living in Patna, Bihar, India 2020.

Childhood lead exposure remains a key health concern for officials worldwide, contributing some 600,000 new cases of intellectually disabled children annually. Most children affected by high exposure to lead live in low- and middle-income countries. The leaded gasoline phase out in India was completed in 2000. Yet, in 2020, an estimated 275 million children aged 0 to 9 years had blood lead levels (BLLs) ≥ 5 μg/dL known to adversely affect intelligence and behavior. Lead sources reported in India include spices, cookware, paint, traditional medicines and cosmetics, and lead-acid battery recycling and repair. However, their relative contribution has not been characterized. More than 200 lead pollution sites related to battery recycling and repair activities were identified in Bihar and Jharkhand, India. Ninety percent of the recycling sites had soil lead concentrations exceeding the US Environmental Protection Agency's standards. We compared blood and environmental lead levels in two groups of children in Patna, Bihar. Households in proximity to battery recycling operations (Proximal n = 67) versus households distal to these operations (Distal n = 68). The average age of children was 40 months; 46% were female. Overall, the geometric mean (GM) BLL was 11.6 μg/dL. GM BLLs of children in Proximal and Distal households were not significantly different (10.2 μg/dL vs. 13.1 μg/dL respectively; p≤0.07). About 87% children, 56 Proximal and 62 Distal had BLLs ≥5 μg/dl. Lead concentrations in environmental samples were significantly higher in Proximal households (soil mean 9.8 vs. 1.6 μg/ft2; dust mean 52.9 vs. 29.9 μg/ft2 p<0.001; Proximal vs. Distal respectively) whereas concentrations in all spices were higher in Distal households (mean 46.8 vs 134.5 ppm p<0.001; Proximal vs. Distal respectively), and turmeric (mean 59.4 vs. 216.9 ppm Proximal vs. Distal respectively). In multivariate analyses for all children lead in spices and turmeric and number of rooms in the house were significant while for the Proximal group only lead in spices remained in the model. The predictive value of these models was poor. For the Distal group, a model with lead concentration in spices, turmeric and soil and number of rooms in the house was a much better fit. Of the 34 water samples collected, 7 were above the Indian standard of 10 ppb for lead in drinking water (2 in the Proximal area, 5 in the Distal area). Children in Patna, Bihar, India are exposed to multiple sources of lead, with lead levels in house dust and loose, locally sourced spices the most likely to increase blood lead levels. A holistic approach to blood lead testing and source identification and remediation are necessary to prevent lead exposure.

Association between lower-level of environmental lead exposure and reactive and proactive aggression in youth: Sex differences

Lead exposure during childhood has been associated with a variety of negative outcomes, including antisocial/aggressive behavior. However, different subtypes of antisocial behavior have been found to have different neurobiological correlates, and it is unclear whether lead exposure is related to specific subtypes of aggressive behavior. The objective of the study was to examine relationships between childhood blood lead levels (BLL) and proactive and reactive aggression. Further, given prior findings of sex differences in the effects of lead exposure, we examine whether there are sex differences in these relationships. In a sample of 818 youth (47.2% girls) ages 10–13 in China, we assessed BLL and administered the Reactive Proactive Aggression Questionnaire. Results show that BLLs were associated with reactive, but not proactive aggression. There was a significant interaction between BLL and sex in predicting aggression; boys with higher BLL scored higher in both proactive and reactive aggression than boys with lower BLL, but these differences were not present for girls. These findings suggest that lead exposure may have broad effects on antisocial behavior, but that boys may be more susceptible than girls. These findings may provide insights to identifying protective factors that could be potential targets for intervention.

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.

Do Neighborhood Factors Modify the Effects of Lead Exposure on Child Behavior?

Lead exposure and neighborhoods can affect children’s behavior, but it is unclear if neighborhood characteristics modify the effects of lead on behavior. Understanding these modifications has important intervention implications. Blood lead levels (BLLs) in children (~7 years) from Montevideo, Uruguay, were categorized at 2 µg/dL. Teachers completed two behavior rating scales (n = 455). At one-year follow-up (n = 380), caregivers reported child tantrums and parenting conflicts. Multilevel generalized linear models tested associations between BLLs and behavior, with neighborhood disadvantage, normalized difference vegetation index (NDVI), and distance to nearest greenspace as effect modifiers. No effect modification was noted for neighborhood disadvantage or NDVI. Children living nearest to greenspace with BLLs < 2 µg/dL were lower on behavior problem scales compared to children with BLLs ≥ 2 µg/dL. When furthest from greenspace, children were similar on behavior problems regardless of BLL. The probability of daily tantrums and conflicts was ~20% among children with BLLs < 2 µg/dL compared to ~45% among children with BLLs ≥ 2 µg/dL when closest to greenspace. Furthest from greenspace, BLLs were not associated with tantrums and conflicts. Effect modification of BLL on child behavior by distance to greenspace suggests that interventions should consider both greenspace access and lead exposure prevention.

A microplasma optical emission spectrometry pen for point-of-care diagnosis of child blood lead

Blood lead levels (BLL) of children have attracted considerable attention due to their putative impact on intelligence decline. However, most methods used for the determination of blood lead typically require expensive, bulky, high power and gas consuming instrumentation, limiting their application for a point-of-care diagnosis. Herein we report the development and testing of a portable ballpoint discharge microplasma optical emission spectrometer (BD-OES pen) device having the potential to fill this needed measurement capability. The BD-OES pen utilizes a compact ballpoint-pen format integrating point-discharge microplasma, which permits the determination of child BLL requiring no more than 100 μL blood while providing high specificity, sensitivity and satisfactory limit of detection (0.73 μg L−1). The handheld BD-OES pen is successfully used to diagnose BLL of 16 asymptomatic children on-site, two of whom had excessive the normal BLL. The pen may aid the on-site and rapid diagnosis of childhood BLL, particularly in low-income areas.

Low level lead exposure in early childhood and parental education on adolescent IQ and working memory: a cohort study.

The independent effect of lead exposure and parental education on children's neurocognition is well-documented. However, few studies have examined the combined effect of childhood lead exposure and parental education on adolescent neurocognition, especially in China. Examine both the combined and interactive effect of childhood blood lead levels (BLLs) and parental education on early adolescent neurocognition. 417 children from a longitudinal cohort study in Jintan, China had BLLs measured at 3-5 years and 12 years, parental education levels assessed at 3-5 years, and neurocognitive outcomes tested at 12 years. BLLs at 3-5 years were inversely associated with adolescent IQ (β -0.55 95% CI: -0.97, -0.13) but not working memory (β -0.06 95% CI: -0.23, 0.11) and parental education was positively associated with adolescent IQ (β 0.68 95% CI: 0.19, 1.17) and working memory (β 0.24 95% CI: 0.04, 0.44). BLLs and parental education evidenced combined effects on neurocognition, where children with higher BLLs and lower fathers' education had mean IQ scores 7.84 (95% CI: -13.15, -2.53) points lower than children with lower BLLs and higher fathers' education. There were significant associations between parental education and working memory, however, not with BLLs. The interaction between mother and father high school education and BLLs was insignificant for effects on IQ and working memory. Childhood lead exposure and parental education levels have a combined and long-term impact on IQ, evidence that may partially explain disparities in lead exposure associated outcomes and highlight those children at greatest risk for neurocognitive deficits. Children continue to be exposed to low-levels of environmental lead in China and globally, warranting examination of the impact of such exposures. This paper demonstrates that even relatively low-level lead exposure in early childhood significantly influences adolescent neurocognitive functioning. Furthermore, co-existing social determinant of health-related variables, measured here as parental education, have a combined impact on neurocognition. These results highlight children at greater risk for neurocognitive deficits and demonstrate the need to examine the influence of lead exposure within the broader socio- ecological environment, as these factors work in tandem to influence longer-term neurocognitive outcomes.

Delta-Aminolevulinic acid dehydratase enzyme activity and susceptibility to lead toxicity in Uganda’s urban children

Background: Rapid industrialization, urbanization, and population explosion in sub-Saharan Africa escalate environmental lead levels and subsequently blood lead levels in children. Its levels in one’s environment account for their blood lead levels. One’s susceptibility to lead toxicity is governed by nutrition status, age and genetics. This study aimed at expounding susceptibility to lead toxicity by relating blood lead levels, delta-aminolevulinic acid dehydratase (ALAD) enzyme activity, and genetic variations of proteins that code for ALAD in urban children of Uganda. Methods: A total of 198 blood samples were spectrophotometrically analysed for blood lead levels (BLL), hemoglobin (Hb) levels, and ALAD enzyme activity before DNA extraction, polymerase chain reaction, and restriction fragment length digestion for ALAD polymorphism. Results: Up to 99.5% of the total samples analyzed coded for ALAD1 allele compared to 0.05% that coded for ALAD2. There was a significant relationship between BLL, Hb status and ALAD enzyme activity in the three isozymes (ALAD1-1, ALAD1-2 and ALAD2-2) in strength of ALAD1-1 (r = 0.42, p -value = 0.02) ˂ ALAD1-2 (r = 0.62, p -value = ˂ 0.001) ˂ ALAD2-2 (r = 0.67, p -value = ˂ 0.001). Conclusions: Majority of children in Uganda code for the ALAD1 allele, which is important for blood lead ions hoarding during lead toxicity. Hoarding of blood lead not only delays exposure effects but also accumulates its levels in deposit tissues and this poses adverse effects later in their lives