Mean Blood Lead Levels Research Articles

Correlation between maternal and fetal umbilical cord blood lead concentrations in Libya.

People are exposed to lead from car exhaust fumes (leaded petrol), lead-based paints, plumbing systems, cigarette smoking, contaminated soil and dust, foods grown in polluted areas, and water sources. Among the vulnerable subpopulations are pregnant women, fetuses and infants. To estimate and correlate maternal and neonatal blood lead levels and compare these between neonates and their mothers in Tripoli and Ghadames. In this cross-sectional study, blood was collected from 120 and 116 mothers and their neonates from Tripoli and Ghadames, respectively. Lead levels were determined using atomic absorption spectrophotometry. A simple questionnaire was filled by the participants using face-to face interview. Data were analysed using SPSS version 20.0 and Excel. Mean blood and umbilical cord lead levels were 6.83 (standard deviation 4.96) and 6.05 (4.89) µg/dl in mothers and neonates from Tripoli, respectively, and 5.91 (4.02) and 4.54 (4.09) µg/dl from Ghadames. There was no significant difference in blood lead level between mothers from Tripoli and Ghadames. However, there was a significant correlation between maternal blood and umbilical cord blood in Tripoli and Ghadames. Linear regression revealed that neonatal umbilical cord blood lead levels reflected the levels in maternal blood. Blood lead in this study was higher than that reported in industrialized western countries. We detected moderate blood lead levels among pregnant women in Tripoli and Ghadames. It is important to detect the source of lead in the Libyan population to treat this problem effectively.

Response of Iron Deficiency Markers to Blood Lead Levels and Synergistic Outcomes at Prenatal Stage.

Lead may be passed on from a mother to their unborn fetus. If she has been exposed to lead for an extended period, the lead deposited in their bones can be stimulated to be released into the bloodstream during gestation. This study was planned to examine blood lead level at the prenatal stage and its response to markers of iron deficiency during gestation. We collected 396 samples during the second trimester of gestation from women age 19 to 45 years. Hematological markers including hemoglobin, hepcidin, total iron-binding capacity (TIBC), ferritin, and blood iron were analyzed. For the detection of blood lead, we used Atomic absorption spectroscopy. The mean blood lead level of the control group was 3.25 ± .407 μg/dL, and in the iron deficiency group, it was 7.96 ± .502 μg/dL. At the same time, the women with iron deficiency anemia showed 22.12 ± 1.02 μg/dL of mean blood lead. Pearson’s approach showed a non-significant negative correlation between blood lead and hepcidin, while hemoglobin, total iron-binding capacity, ferritin, and serum iron showed a significant (.01) negative correlation with blood lead. Blood lead has no direct effect on iron deficiency markers. In contrast, iron deficiency contributes to an increase in lead accumulation during pregnancy. Iron and lead both have an impact on the heme-biosynthetic pathways. The study revealed that pre-existing iron deficiency is connected with increased lead intake and can negatively impact health in gestational females.

A review of studies on blood lead concentrations of traditional Mexican potters.

Traditional Mexican potters and their families have been occupationally exposed to lead for centuries; however, studies on blood lead levels (BLL) and their adverse health impact on this population are scarce. There is no safe BLL, even at 1μg/dL there are associated health effects. To systematize and characterize Mexican potters' historic lead exposure through their BLL and associated health outcomes. Using PRISMA guidelines, we conducted a systematic review through January 2021 of published studies on BLL and associated health outcomes in Mexican potters. Fifteen studies containing data from 1980 to 2013 met the inclusion criteria and were published between 1980 and 2018. Study populations ranged from n=5 to n=457, and included adult potters (mean BLL 37.9±16.2μg/dL) and/or their children (mean BLL 22.5±10.5μg/dL). Studies reported on general lead poisoning symptoms, neurotoxic and nephrotoxic outcomes as well as correlated biomarkers. Our results confirm high occupational and para-occupational lead exposure. Despite governmental and non-governmental initiatives to promote lead-free glazes, lead continues to be used by traditional potters and their families.

Abstract P104: High Lead Levels Associated With Elevated Blood Pressure In Haiti: A Warning Sign

Introduction: Cardiovascular disease is the leading cause of death in Haiti and many low-middle income countries. Environmental lead exposure is associated with higher blood pressure (BP) and cardiovascular disease mortality in high income countries but has not been systematically evaluated in lower income countries where 6.5 billion people reside. Hypothesis: We hypothesized higher lead levels would be associated with higher BP in Haiti. Methods: Blood lead levels (BLLs) were measured among 2,257 participants ≥18 years enrolled in a population-based longitudinal cohort study in Port-au-Prince (Haiti Cardiovascular Disease Cohort Study). BLL screening was conducted using LeadCare II (detection limit ≥3.3 μg/dL). BLLs below detection were imputed. Associations between BLLs (quartiles) and systolic BP (SBP) and diastolic BP (DBP) were assessed, adjusting for age, sex, obesity, smoking, physical activity, and income. BLLs were also categorized as ≥5 versus <5 μg/dL. Results: The median age was 40 years; 62.6% were female. The geometric mean BLL was 4.60 μg/dL, 67.3% had detectable BLLs >3.3 μg/dL, and 40.9% had elevated BLLs ≥5 μg/dL. BLLs in quartile four (≥6.5 μg/dL) in both unadjusted and adjusted analyses were associated with higher SBP (adjusted 3.02 mmHg; 95%CI 0.80, 5.25) and DBP (adjusted 2.19 mmHg; 95%CI 0.70, 3.67). BLL ≥5 μg/dL were associated with a higher SBP (2.21 mmHg; 95%CI 0.15, 4.26) and DBP (1.50 mmHg; 95%CI 0.20, 2.81) in unadjusted analysis. After adjustment there was no difference in SBP (1.41; 95%CI -0.25, 3.09) and 1.15 mmHg (95%CI 0.01, 2.30) higher DBP. Conclusions: Widespread environmental lead exposure is evident in urban Haiti, with higher BLLs associated with higher SBP and DBP. Lead is a modifiable pollutant in low-income countries that warrants urgent public health remediation.

Association Between Blood Lead Levels and Hypertension in a South Indian Population: A Case-Control Study.

BackgroundExposure to lead and its accumulation in the body can lead to progressive adverse effects, including increased blood pressure which is associated with the onset of cardiovascular diseases. In this study, we aimed to determine the relationship between blood lead levels and blood pressure. In addition, we compared blood lead levels between hypertensives and normotensives to determine relationships, if any, between lead exposure and high blood pressure.MethodologyThis was a hospital-based, case-control study. In total, 102 individuals (hypertensives = 51, normotensives = 51) were included in this study. Hypertensive patients (defined as systolic blood pressure (SBP) of ≥140 mmHg, diastolic blood pressure (DBP) of ≥90 mmHg, or taking antihypertensive medication for regulating blood pressure) were considered to be study cases and normotensive individuals were considered to be study controls. Blood lead levels were compared between the two groups, and the effects of blood lead levels on SBP and DBP were estimated. The blood lead levels were measured using optical emission spectrometry.ResultsThe mean blood lead level among hypertensive individuals (5.5743 ± 1.77 µg/dL) was significantly higher compared to normotensive individuals (4.5029 ± 1.3213 µg/dL, P = 0.001). A positive correlation was detected between blood lead levels and SBP (r = 0.304, P = 0.002). However, no significant correlation was found between blood lead levels and DBP.ConclusionsBlood lead levels were significantly higher in hypertensive patients compared to normotensive individuals. A significant positive correlation was observed between blood lead levels and SBP.

Association between blood lead levels and markers of calcium homeostasis: a systematic review and meta-analysis

Chronic Pb exposure associated systemic illness are partly posited to involve calcium homeostasis. Present systematic review aims to comprehensively evaluate the association between chronic lead exposure and markers of calcium homeostasis. Observational studies documenting the changes in calcium homeostasis markers (i.e. serum calcium, parathyroid hormone, vitamin D & calcitonin) between occupationally Pb exposed group and control group were systematically searched from pubmed-Medline, Scopus, and Embase digital databases since inception to September 24, 2021. The protocol was earlier registered at PROSPERO (ID: CRD42020199503) and executed adhering to PRISMA 2020 guidelines. Mean differences of calcium homeostasis markers between the groups were analysed using random-effects model. Conventional I2 statistics was employed to assess heterogeneity, while the risk for various biases were assessed using Newcastle Ottawa Scale. Sub-group, sensitivity and meta-regression analyses were performed where data permitted. Eleven studies including 837 Pb exposed and 739 controls were part of the present study. Pb exposed group exhibited higher mean blood lead level [i.e. 36.13 (with 95% CI 25.88–46.38) µg/dl] significantly lower serum calcium (i.e. − 0.72 mg/dl with 95% CI − 0.36 to − 1.07) and trend of higher parathyroid levels and lower vitamin D levels than controls. Heterogeneity was high (I2 > 90%) among the studies. Considering the cardinal role of calcium in multiple biological functions, present observations emphasis the need for periodic evaluation of calcium levels and its markers among those with known cumulative Pb exposure.

Blood Lead Levels in Children Living Near Lead Smelting Zone: A Pilot Field Study

Introduction: Children are most susceptible to lead toxicity. Exposure to lead in the environment still exists in various pockets of urban cities due to continued practices of using lead in jewellery making, paints, battery smelting and in cosmetics. Aim: To evaluate Blood Lead Level (BLL) and its association with haemoglobin, Red Blood Corpuscle (RBC) indices and bone parameters (vitamin D, parathyroid hormone, calcium, phosphorus, and Alkaline Phosphatase (ALP) in children residing near lead battery smelting units of Kolkata. Materials and Methods: This was a cross-sectional field-based study carried out by Institute of Child Health, Kolkata. A camp was organised in the month of August 2015 at a known major cluster of secondary lead smelting area ward no. 66 in the Kolkata metropolitan district. A total of 45 camp attending children were enrolled. BLL was measured using graphite furnace atomic absorption spectrometry, and association with haematological and bone parameters were evaluated. Results: Mean age of the participants was 5.6±3.3 years, and mean BLL was 3.7±1.9 μg/dL (range:1.3-8.2). About 35 children were found to have Low BLL<5 μg/dL (LBLL, 2.88±1.08) while 10 had elevated BLL≥5 μg/dL (EBLL, 6.59±0.95) (p<0.0001). Red Cell Distribution Width (RDW) was high (p=0.03) and Mean Corpuscular Volume (MCV) was low (p=0.05) in EBLL group; but there was no significant difference in haemoglobin level, compared to LBLL group. The mean vitamin D level was 15.2±8.7 ng/mL, while 23 (51%) were severely deficient without concomitant rise in parathyroid hormone (mean, 37.9±0.7 pg/mL). Calcium, phosphorous and ALP were within normal reference range. None of the bone parameters showed any correlation with BLL. Conclusion: Overall, 22% children of the cohort had elevated BLL, beyond the permissible safety limit of 5 μg/dL but within 10 µg/dL. Mildly elevated BLL relate to iron deficient hematopoiesis (increased RDW and low MCV) without any apparent affection of bone metabolism.

Iron deficiency and cognitive impairment in children with low blood lead levels

BackgroundThe relationship between iron deficiency (ID) and children's neurocognitive functions has attracted the interest of the scientific community, particularly among those living at the lead-contaminated sites. Thus, the current paper aims at evaluating the association between ID and neurocognitive performance of school children living in a mining area (CMA) in comparison with a control group (CG). Methodshe study involves 90 school children aged from 6 to 10 years old. A survey was conducted to obtain information on the socio-economic and demographic status of the children. The students underwent cognitive test battery including the Bell Dam Test (BDT) and the Digit Span test (DST). Iron status (IS) was determined by serum iron, ferritin, transferrin, and blood count (CBC). Blood lead levels (BLLs) were measured by the Graphite Furnace Atomic Absorption Spectrophotometer (SAA-FG). ResultsAn ID was observed in 23.3 % of CMA, but it is not statistically different from the CG 21.7 % (p = 0.774). CMA group exhibited elevated BLLs (3.5 ± 1.21 µg/dL) when compared to the CG (2.31 ± 0.95 µg/dL), p = 0.006. Children's performance on the visual attention test (VA) was impaired in both groups. Working memory (WM) abilities were normal. In bivariate analysis, no difference was demonstrated in mean BLLs between the students who adopt the disorganized scanning strategy compared to the others whose method is organized for both CMA (t = − 0.508, p = 0.616) and CG (t = − 0.014, p = 0.989). Multivariate models did not reveal any association between IS and cognitive scores of children in the two groups (p > 005). Nevertheless, daily milk consumption was positively associated to VA skills among CMA. A negative influence of BLLs above the threshold value of 5 µg/dL was determined on children's WM skills. ConclusionOur results suggest that low-level lead exposure did not influence children's visual attention scores but may adversely affect WM abilities if it reaches the threshold value of 5 µg/dL regardless of their IS.

Early childhood lead exposure and adolescent heart rate variability: A longitudinal cohort study

Lead is a known neurotoxicant with many detrimental health effects, including neurocognitive deficits and cardiovascular and metabolic disorders. However, few studies have tested the association between lead exposure and the physiological stress response, which in and of itself may act as a precursor to and/or underlying mechanism of detrimental health outcomes. The purpose of this study was to examine the influence of early childhood and early adolescent low-level lead exposure on early adolescent heart rate variability, a widely-used measure of physiological stress. Participants were 408 children from Jintan, China for whom blood lead levels were measured between 3 and 5 years (early childhood) and again at 12 years (early adolescence). Heart rate variability was assessed at 12 years while participants underwent an induced stress task utilizing the ratio of low to high frequency (LF/HF) ECG measures. Mean blood lead levels in the cohort were 6.63 mcg/dl and 3.10 mcg/dl at 3–5 years and 12 years, respectively. Blood lead levels at 3–5 years of age (β 0.06, p = 0.027), but not at age 12 (β −0.05, p = 0.465), were significantly associated with LF/HF measures while controlling for multiple sociodemographic variables, potentially reflecting a dysregulated stress response with a shift towards sympathetic dominance. These findings suggest that early childhood lead exposure may have a detrimental influence on early adolescent autonomic responses to acute stress, which holds implications for cardiovascular health and overall growth and development.

Evaluation of blood lead among painters of buildings and cars.

Exposure to lead-based paints is a major threat to the health of painters. This study aimed to evaluate the blood concentration of lead (Pb) in painters of buildings and cars. The present study was a cross-sectional study in which a semi-structured questionnaire was used to collect the socio-demographic information. Lead concentration in blood samples was determined using the atomic absorption spectrometry method. A total of 32 male painters were selected based on inclusion criteria. The mean blood lead level (BLL) in the painters was 8.1 ± 4.93μg/dL. Pb levels in car and building painters were 9.42 ± 5.5μg/dL and 6.7 ± 1.85μg/dL, respectively. Pb concentration in none of the blood samples was more than 30μg/dL. The prevalence of BLL ≥ 5μg/dL and BLL ≥ 10μg/dL was 97% and 19%, respectively. According to the findings, the rate of BLL among car painters was higher than building painters. Considering the presence of Pb in all blood samples, it seems necessary to increase the awareness of painters about the adverse effects of lead exposure even in low concentrations. However, the sample size in this study was small and more investigations are required in this regard.

Blood lead levels mediate the relationship between social adversity and child externalizing behavior

Background/aimsThe association between social adversity and externalizing behavioral problems in children is well-documented. What is much less researched are biological mechanisms that may mediate such relationships. This study examines the hypothesis that low blood lead mediates the relationship between social adversity and child externalizing behavior problems. MethodsIn this cross-sectional study, participants were 131 children aged 11–12 years (mean = 11.90) from Philadelphia, US. A venous fasting blood sample was taken and analyzed for blood lead levels. A social adversity index was calculated based on 10 total indicators derived from a psychosocial interview of the parent and official neighborhood data, while child behavior outcomes (internalizing and externalizing behavior) were assessed using both parent-report and child self-report. ResultsThe mean blood lead level was 2.20 μg/dL. Both relatively higher blood lead levels and higher social adversity scores were associated with higher levels of parent-reported and child self-reported externalizing behaviors. Additionally, blood lead mediated the relationship between social adversity and child-reported externalizing behavior (Indirect effect: B = 0.03, 95% CI: 0.004, 0.09) and partially mediated the relationship between social adversity and parent-reported externalizing behavior (Indirect Effect: B = 0.03, 95% CI: 0.01, 0.07). ConclusionTo our knowledge, this study is the first to suggest that blood lead levels play a mediating role in the relationship between externalizing behavior problems and social adversity. Findings have potentially important implications for public health and environmental regulation as well as understanding biological mechanisms that link social inequality with health outcomes, especially in youth from low-income, urban areas.

High Lead Exposure Associated With Higher Blood Pressure in Haiti: a Warning Sign for Low-Income Countries.

Cardiovascular disease is the leading cause of death in lower-income countries including Haiti. Environmental lead exposure is associated with high blood pressure and cardiovascular mortality in high-income countries but has not been systematically measured and evaluated as a potential modifiable cardiovascular risk factor in lower-income countries where 6.5 billion people reside. We hypothesized lead exposure is high in urban Haiti and associated with higher blood pressure levels. Blood lead levels were measured in 2504 participants ≥18 years enrolled in a longitudinal population-based cohort study in Port-au-Prince. Lead screening was conducted using LeadCare II (detection limit ≥3.3 µg/dL). Levels below detection were imputed by dividing the level of detection by √2. Associations between lead (quartiles) and systolic blood pressure and diastolic blood pressure were assessed, adjusting for age, sex, obesity, smoking, alcohol, physical activity, income, and antihypertensive medication use. The median age of participants was 40 years and 60.1% were female. The geometric mean blood lead level was 4.73µg/dL, 71.1% had a detectable lead level and 42.3% had a blood lead level ≥5 µg/dL. After multivariable adjustment, lead levels in quartile four (≥6.5 µg/dL) compared with quartile 1 (<3.4 µg/dL) were associated with 2.42 mm Hg (95% CI, 0.36-4.49) higher systolic blood pressure and 1.96 mm Hg (95% CI, 0.56-3.37) higher diastolic blood pressure. In conclusion, widespread environmental lead exposure is evident in urban Haiti, with higher lead levels associated with higher systolic and diastolic blood pressure. Lead is a current and potentially modifiable pollutant in lower-income countries that warrants urgent public health remediation. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03892265.

Preschool blood lead levels, language competency, and substance use in adolescence

BackgroundElevated lead levels in children are a persistent public health problem, particularly in urban areas in the United States, yet few prospective studies have examined the association of childhood lead levels with substance use in adolescence. ObjectivesTo determine the association of early lead levels with adolescent substance use and whether childhood IQ, language skills, and externalizing (aggressive and disruptive) behavior mediate the association, controlling for confounding biological and environmental factors. MethodsThe participants (N = 265) were a subsample of a prospective birth cohort study on the developmental effects of prenatal cocaine exposure in the Midwest United States. Blood lead levels (BLL) were assessed at age 4, IQ at age 11, language skills and externalizing behavior at age 12, and substance (alcohol, tobacco, marijuana) use and substance use-related problems at age 15. Biologic assays (hair, urine, bloodspots), along with self-report, were utilized to determine adolescent substance use. Path analyses were conducted to examine the direct and indirect associations of BLL with adolescent substance use. ResultsThe children's mean BLL at 4 years of age was 7.07 (SD = 4.12) μg/dL. Approximately 31% of adolescents used tobacco or marijuana, 40% used alcohol, and 23% reported experiencing substance use-related problems at age 15.7 (SD = 0.28). Elevated BLL was related to a higher likelihood of substance use. Childhood language skills fully mediated the relationship of BLL with substance use-related problems. IQ was related to neither substance use nor substance use-related problems. DiscussionElevated BLL in preschool years is a risk factor for adolescent substance use and related problems. Early screening and intervention for language impairment may reduce substance use-related problems.

Blood Lead Level among Children between 8-18 years of Age by Atomic Absorption Spectrophotometry: A Descriptive Cross-sectional Study.

Lead is naturally available toxic heavy metal which is one of the main causes of environmental pollution and produces detrimental effects on health, particularly young children. Lead toxicity has become an emerging global burden of disease varying with the age, socio-economic status, occupation, industrialization, social customs and behaviours. The objective of this study was to find out the baseline blood lead level among children between 8-18 years. A descriptive study was conducted in Gokarneshwor Municipality, Kathmandu with a total of 160 children between 8-18 years of age from 2018 to 2019 after taking ethical approval from Research and Institutional Review Committee (Reference number: 17-074/075). Informed written consent was taken from the principal along with their respective parents and semi structured questionnaires were asked to students. Sample size was calculated and simple random sampling was done. The data was analyzed using Statistical Package for Social Science version 16. Point estimate at 95% Confidence Interval was calculated along with frequency and descriptive statistics. The mean blood lead level of the children was 4.39±7.35 µg/dl. Mean hemoglobin being 12.63g/dl; out of 160 children 30 (18.75%) children had blood lead levels. Children with elevated blood lead level had mean haemoglobin level within normal range (13.05gm/dl), however out of 30 children, 8 (27%) had haemoglobin level below normal. Lead exposure in the children of urban area of Nepal is considerably high as compared to similar studies coducted in similar settings.

The Effects of Succimer and Penicillamine on Acute Lead Poisoning Patients

Background: Lead poisoning was on the rise in recent years. There exists a lack of easy access to some of the main chelator drugs in developing countries. Thus, this study aimed to explore the comparative effects of Succimer and D-Penicillamine on acute lead poisoning patients from 2013 to 2018. Methods: This descriptive study was conducted in the Clinical Toxicology Department of Khorshid Hospital in Isfahan City, Iran. Adult patients with acute lead poisoning were included in the study. Patients in the 3 treatment groups of D-Penicillamine, D-Penicillamine with succimer, and succimer were compared concerning demographic characteristics as well as clinical and laboratory findings at admission time and two weeks later. Results: In total, 163 patients were evaluated in this research. There was no significant difference between the treatment groups respecting improvement in clinical symptoms. The mean blood lead levels during hospitalization and two weeks after the treatment did not significantly differ between the three groups; however, there was a significant reduction in all study groups after two weeks of treatment (P&lt;0.05). The mean white blood cell count was significantly lower only in the D-Penicillamine group two weeks after hospitalization (P&lt;0.05). In the D-Penicillamine group, the mean platelet, hematocrit, and hemoglobin levels were significantly lower two weeks after hospitalization, although within the healthy range. Conclusion: D-Penicillamine may be an acceptable chelator drug for treating patients with acute lead poisoning, especially in communities without access to drugs, like succimer.

Lead screening in children presenting to three hospitals in Lebanon

BackgroundLead damages most body organs and its effects are most profound in children. In a study in Beirut in 2003, before banning the leaded gasoline, 79% of the participants showed...

Blood lead concentrations in traditional Mexican potters through four decades

BACKGROUND AND AIM: Traditional pottery in Mexico is produced using lead-based glazes, resulting in high occupational and environmental exposure to lead. There are over 10,000 traditional potters and their families that continue to use this technology. We aimed to systematize and characterize traditional Mexican potters’ historic lead exposure through their blood lead levels (BLL). METHODS: Using PRIMSA guidelines, we conducted a systematic review of published studies that included BLL in Mexican potters through January 2021. BLL data reported and main study population characteristics were extracted. Studies that included a non-potter comparison group were used to analyze BLL differences. RESULTS:A total of 15 studies were published with BLL sampled between 1980 and 2013. Except for one study, non-potters (n= 838) lived in the same communities as potters (n= 998). Across the study period, the mean BLL in potters was twice as high as non-potters (41.8±13.1 vs. 19.5±12.4 µg/dL, p0.001). Among potters, adult men had higher BLL than women (40.6 ± 13.9 vs 23.3 ± 17.5 µg/dL), and adults had higher BLL than children and adolescents (38.3 ± 15.8 vs 32.8 ± 13.6 µg/dL). Among non-potters, children and adolescents had higher BLL than adults (23.4 ± 2.6 vs 18.5 ± 16.4 µg/dL). Average BLL for potters decreased from 55.6 ± 7.7 µg/dL in 1980 to 19.3 ± 6.4 µg/dL in 2013. Potters whose main activity was firing the kiln (50.7± 12.9 µg/dL), applying glaze (45.8± 4.4 µg/dL), and sieving (43.9 µg/dL) had the highest BLLs. CONCLUSIONS:Traditional potters’ BLLs and health effects have been scarcely studied throughout the years. The use of lead-based glazes persists with no surveillance of potters’ BLL or health. There is an urgent need for a sound policy for the use of lead-free glazes in traditional Mexican pottery. KEYWORDS: Occupational lead exposure, Traditional Pottery, Surveillance, Lead

Blood Lead Levels in U.S. Children Ages 1-11 years over the 40-year period from 1976 to 2016

BACKGROUND AND AIM: Blood lead levels (BLLs) have generally declined over the past 40 years in the United States (U.S.).We describe the distribution of BLLs in U.S. children age 1-11 years from 1976-2016 and associations with demographic, housing and regional characteristics. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) II, NHANES III 1988-1991 and 1991-1994, and 1999-2016 NHANES cycles were used to describe the distribution of BLLs in U.S. children age 1-5 years and 6-11 years from 1976-2016. For all children with valid BLLs (n=27,122), geometric mean (GM) BLLs (95% confidence intervals [CI]) and estimated prevalence were calculated overall, stratified by age group (1-5 years; 6-11 years) and selected characteristics. RESULTS:The GM BLL in U.S. children age 1-5 years has declined from 15.2 µg/dL (CI 14.3,16.1) in 1976-1980 to 0.83 µg/dL (CI 0.78,0.88) in 2011-2016, representing a 94.5% decrease over time. A large portion of this decline occurred before 1992 as GM BLLs for 1-5 year olds had decreased to 3.6 µg/dL (CI 3.2,4.0) by 1988-1991. For children age 6-11 years old, GM BLL have declined from 12.7 µg/dL (CI 11.9,13.4) in 1976-1980 to 0.60 µg/dL (CI 0.58,0.63) in 2011-2016, representing a 95.3% decrease. As with the younger age group, much of this decrease occurred before 1992. Despite this substantial decline, disparities exist by income, race/ethnicity, and housing age. CONCLUSIONS:Lead exposure in U.S. children age 1-5 years and 6-11 years has substantially decreased over this forty-year period. Despite this significant achievement, children, particularly those of minority and low-income backgrounds, are still at risk of lead exposure. Risk factors, such as income and housing age, persist throughout regardless of child’s age. NHANES estimates of BLLs have played a key role in monitoring the decline in BLLs in U.S. children and have influenced public health action and national policy around childhood lead exposure. KEYWORDS: Epidemiology, children's environmental health, heavy metals

Prolonged blood coagulation time among occupationally exposed automobile technicians in Abeokuta, Nigeria.

Automobile technicians in resource-poor settings often work in poor environments and are exposed to chemicals that put them at risk of ill health and disease. These chemical exposures could affect blood coagulation, leading to bleeding disorders or thrombosis. The present study is aimed at assessing prothrombin test (PT) and activated partial thromboplastin test (aPTT) values, serum zinc (Zn) and copper (Cu) concentrations, and blood lead level (BLL) among occupationally exposed automobile technicians compared to unexposed controls. A total of 140 consenting participants comprising 70 automobile technicians and 70 unexposed controls were recruited for this case-control study. A 6-mL blood sample was drawn from each participant for estimation of BLL, serum Zn and Cu concentrations, and PT and aPTT values. Blood lead level, and serum Zn and Cu concentrations were determined using atomic absorption spectrophotometry, while PT and aPTT values were determined using Innovin PT and Actin FS Activated PTT reagents on the Sysmex CA-101 coagulation analyser. Data were analysed using t-tests, chi-square tests, and logistic and multiple linear regression analyses with statistical significance set at p < 0.05. The mean BLL, serum Zn concentration, and PT and aPTT values were significantly higher in automobile technicians compared to controls. Binary logistic regression showed that automobile technicians had higher odds of elevated PT value (OR = 21.769; p = 0.000), aPTT value (OR = 1.348; p = 0.018), BLL (OR = 1.261; p = 0.000) and serum Zn concentration (OR = 1.063; p = 0.005) than unexposed controls. Linear regression showed significant positive association of PT value with BLL and with serum Zn concentration. Higher PT and aPTT values reflect prolonged blood coagulation time among automobile technicians, which indicates impairment of extrinsic and intrinsic coagulation pathways associated with work-related exposures.

Blood Lead Levels and Subsequence Risk of Malaria in the African Population: A Systematic Review and Meta-Analysis.

Previous epidemiological studies showed that blood lead level (BLL) was associated with malaria infection and severity. Therefore, the present study aimed to qualitatively and quantitatively synthesize the evidence on the association between BLL and risk of malaria infection and severity using the systematic review and meta-analysis approach. Potentially relevant studies were identified from three databases using a combination of search terms. The quality of the included studies was assessed using the checklist for the cross-sectional studies developed by the Joanna Briggs Institute. The qualitative synthesis of the risk or odds of malaria infection in patients with BLL was performed as the outcome of each included study could not be pooled. The pooled mean BLL and prevalence of malaria infection of the included studies was estimated using a random-effect model. The heterogeneity of the outcomes among the included studies was assessed using the Cochran Q test and I2 statistics. The subgroup analysis of the study sites and participants was performed to explore the source(s) of heterogeneity of the outcomes. Publication bias was assessed in the case of more than 10 studies used for pooling of the same outcome. Among 114 potentially relevant studies identified from the databases, 6 eligible studies were included for qualitative and quantitative syntheses. The results showed that the pooled mean BLLs were 7.33 μg/dL in children (95% confidence interval (95%CI), 4.08–10.58; I2, 98.2%), 7.94 μg/dL in children with BLL > 45 mg/dL before chelation (95%CI, 7.87–8.01), 7.41 μg/dL in infants (95%CI, 7.34–7.48 μg/dL), 9.20 μg/dL in children with malaria (95%CI, 9.16–9.24 μg/ dL), and 36.37 μg/dL in pregnant women (95%CI, 34.43–38.31 μg/dL). The prevalence rates of malaria among participants (2381 participants, 803 malaria-positive patients) were 53% in children (95%CI, 50–57%; I2, 99.8%), 24% in children with BLL > 45 mg/dL before chelation (95%CI, 21–27%), 12% in infants (95%CI, 8–18%), and 21% in pregnant women (95%CI, 18–26%). The subgroup analysis of countries demonstrated that the prevalence rates of malaria among participants was 17% in Benin (95%CI, 13–21%; I2, 98.8%) and 36% in Nigeria (95%CI, 10–63%; I2, 99.4%). BLL associated with decreased risk of malaria was demonstrated by two studies conducted in Benin and Nigeria, while BLL associated with increased risk of malaria was demonstrated by a study conducted in Nigeria. BLL was associated with the risk of severe malaria, involving severe neurological features and severe anemia. In conclusion, the present systematic review and meta-analysis determined the current status of the studies on BLL and risk of malaria in African countries. Further studies are needed to investigate the impact of BLL on patients with malaria to help the clinician determine the risk of severity, such as the development of neurological features or severe anemia, among patients exposed to lead.