Elevation Of Blood Lead Levels Research Articles

Maternal Δ-aminolevulinic acid dehydratase 1-2 genotype enhances fetal lead exposure and increases the susceptibility to the development of cerebral palsy.

Limited epidemiologic studies questioned the association between pre- and postnatal lead exposure and the development of cerebral palsy (CP). Moreover, the genotypes of δ-aminolevulinic acid dehydratase (δ-ALAD) in CP patients and their mothers and their association to the blood lead levels (BLLs) were not previously studied. This study aimed to evaluate the association between δ-ALAD gene polymorphism and BLL in cases of CP and their mothers. A case control study was carried out on 23 CP cases and equal number of healthy matched controls. The mothers of the included children were asked to answer a questionnaire involving the baseline clinical and demographic characteristics. Also, questionnaires were done to detect the sources of environmental lead exposure and screen lead exposure during the pregnancy period. BLL, δ-ALAD enzyme activity, and genetic analysis for ALAD G177C were done for each child and his mother. There was significant (p < 0.001) elevation of BLL in CP cases and their mothers that was positively correlated (r = 0.436, p < 0.05). There were progressive decreases in δ-ALAD activity with increasing BLL in both children and mothers (p < 0.05). There were non-significant (p > 0.05) differences between CP and the control group regarding frequency of ALAD G177C genotypes, while there was a significant (p = 0.04) increase in the frequency of ALAD 1-2 (GC) genotype in the mothers of the CP group associated with high BLL and significant decrease in δ-ALAD activity (p < 0.001). The study can indicate the significance of δ-ALAD gene polymorphism in the prenatal exposure to lead and the affection of the developing brain, pointing to the importance of controlling lead in pregnant women especially those with ALAD 1-2 genotype.

Extra-Articular Retained Missiles; Is Surveillance of Lead Levels Needed?

Although gunshot wounds are relatively common, lead toxicity associated with extra-articular retained missiles (EARMs) is an uncommon, yet potentially devastating, complication. Although the risk of lead toxicity with intra-articular retained missiles is well known, EARMs are routinely left in situ or only removed in selected circumstances secondary to the relatively rare occurrence of complications. We first describe a patient with systemic lead poisoning associated with retained lead fragments after a gunshot-induced left femoral shaft fracture. We then performed a systematic review of the literature to answer the following questions: (1) In the setting of retained extra-articular bullets and/or bullet fragments, is regular monitoring and/or surveillance of lead levels in the blood routinely indicated? and, if so, (2) what are the selected factors that portend an increased risk for elevations in blood lead levels in the setting of retained extra-articular bullets and/or bullet fragments? The systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines, of the English language literature utilizing Medline (PubMed), EMBASE, Cochrane, and CINAHL on the topic of lead poisoning, retained bullet, and gunshot wound, and then searched for additional references by manually searching of bibliographies of the included references. Studies were included if they provided clinical data on one or both of our study questions; included studies were evaluated using the accepted levels of evidence. Routine monitoring or surveillance of lead levels in blood is recommended in all cases of EARM at the time of hospital admission and again at discharge, followed by monthly intervals until 3 mo post-injury and then again at 1 yr post-injury. The studies identified demonstrated significant risk factors for elevated blood lead levels in the setting of EARM, which included the number of retained missiles and concomitant fracture. Recommendations for routine monitoring and surveillance of blood lead levels in all cases of EARM are conflicting, but such monitoring appears to be warranted given that the potential risks and morbidity associated with systemic lead poisoning are outweighed by any potential harm of short-term, blood lead level monitoring. Outside of concomitant fracture, the evidence for making further clinical recommendations regarding selected risk factors that portend an increased risk for elevated blood lead levels after gunshot injury is weak. Larger level II and III studies are needed to determine the indications for and frequency of lead toxicity screening after retained EARM.

Primary Prevention of Lead Exposure—Blood Lead Results at Age Two Years

Objectives: The Philadelphia Lead Safe Homes (LSH) Study was designed to evaluate whether educational and environmental interventions in the first year of life for families of newborns increased knowledge of lead exposure prevention and were associated with less elevation of blood lead levels (BLLs) for these children, when compared to children receiving standard care. Methods: The current study performed descriptive statistics on the second-year BLL data for both groups and compared these using chi-square tests for proportions and unpaired t-tests for means. Results: A BLL result was found for 159 (50.6%) of the 314 LSH cohort children and 331 (52.7%) of the 628 control children (p = 0.1). Mean and standard deviation for age at draw was 23.8 (3.4) months versus 23.6 (3.1) months (P = 0.6). Geometric mean BLLs were 3.7 versus 3.5 µg/dL (P = 0.4). The percentages of the cohort group with a BLL of ≥20, ≥10 and ≥5 μg/dL, respectively, were 0.6%, 5% and 30%; for the controls 1.2%, 6.6%, and 25%. These percentages were not significantly different between groups. Conclusion: A comparison of geometric mean BLLs and percentages above several BLL cut points drawn at age two years in a group of urban newborns benefitting from study interventions versus a group of similar urban children did not yield statistically significant differences. Both groups had relatively lower lead levels when compared to historical cohort groups, which may reflect a continuing downward trend in BLLs in U.S. children. The interventions did result in benefits to the families such as an increase in parental knowledge about lead exposure prevention and in-home wet cleaning activity, and a decrease in lead dust levels in study homes.

Blood lead and cadmium levels and relevant factors among children from an e-waste recycling town in China

Background Primitive electronic waste (e-waste) recycling is ongoing in Guiyu, and thus toxic heavy metals may keep on threatening to the health of local children. Some related factors may contribute to the elevation of blood lead levels (BLLs) or blood cadmium levels (BCLs). Objective To investigate the children's BLLs and BCLs in Guiyu and Chendian as compare to discuss the effects of primitive e-waste recycling activities on children's health. Methods Two hundred and seventy-eight children less than 8 years who lived in Guiyu and Chendian were observed, and their BLLs and BCLs were determined by graphite atomizer absorption spectrophotometer. Questionnaire survey for risk factors was also performed and data were analyzed using spearman correlation analyses and logistic regression analyses. Results Children living in Guiyu had significantly higher BLLs and BCLs as compared with those living in Chendian ( p<0.01). In Guiyu, 70.8% of children (109/154) had BLLs>10 μg/dL, and 20.1% of children (31/154) had BCLs>2 μg/L, compared with 38.7% of children (48/124) had BLLs>10 μg/dL and 7.3% of children (9/124) had BCLs>2 μg/L in Chendian ( p<0.01, respectively). We also observed a significant increasing trend in BLLs with increasing age in Guiyu ( p<0.01). Mean height of children in Guiyu was significantly lower than that in Chendian ( p<0.01). The risk factors related to children's BLLs and BCLs mainly included father's engagement in the work related to e-waste, children's residence in Guiyu and the amount of time that children played outside near the road everyday. Conclusions There are close relationships between the BLLs, BCLs in children and the primitive e-waste recycling activities in Guiyu. Environmental pollution, especially lead pollution, has threatened the health of children living around e-waste recycling site.

Blood Lead and Water Treatment

Miranda et al. (2007) recently reported the results of their investigation into the relationship between blood lead levels and residual water treatment in two locations in North Carolina. Their conclusion that “the change to chloramine disinfection may lead to an increase in blood lead levels, the impact of which is progressively mitigated in newer housing” is not borne out by their analysis. Their ecologic study design cannot be used to determine causation, and their recommendation to change lead screening strategies based on their study seems premature. Their analysis relied on ecologic assignment of drinking water exposures based on residence location, census-level exposures for housing age, and other risk factors for lead exposure. They provided no information on differences in water chemistry, such as pH or corrosivity, or on the presence of lead in the distribution systems or service lines. These characteristics are important to determine the likelihood of lead leaching, regardless of the type of residual disinfectant used. In fact, the water serving Wayne County, North Carolina, is heterogeneous. Whereas the city of Goldsboro is served by surface water sources, the rest of Wayne County is served by seven smaller sanitary districts that rely on groundwater. Further, among the groundwater sources there is considerable variability in the water quality. The Wayne Water Districts, erroneously referred to by Miranda et al. (2007) as “Wayne Water Systems,” are composed of five of the seven sanitary districts in Wayne County and had 39 wells in 2006, about half of which receive no treatment. The remaining half are treated for iron removal, fluoride, chlorine, and phosphate. The pH for Wayne Water Districts water ranges from 6.5 to 7.5, whereas Goldsboro Water usually maintains a pH > 8.0. Miranda et al. (2007) stated that they expected that the effect of chloramines on [blood lead levels] would be less important and eventually unimportant as [they] moved into newer and newer housing stock. However, they offered no explanation for their a priori hypothesis of interaction. In fact, according to the U.S. Environmental Protection Agency (1993), the opposite would be true: Lead levels decrease as a building ages. This is because, as time passes, mineral deposits form a coating on the inside of the pipes (if the water is not corrosive). This coating insulates the water from the solder. In the categorical analysis, stratifying housing age by 25-year categories may have led to misclassification. In 1988 the Consumer Product Safety Commission (CPSC 1988) began enforcing the Federal Hazardous Substances Act restricting the use of lead solder in plumbing. The cutoffs used by Miranda et al. (2007) combine the years 1976–1988 together with newer housing stock that would not have lead solder in the plumbing. It is also curious that the tax parcel data from which they assigned housing age characteristics differs markedly from that reported in the 2000 U.S. Census (U.S. Census Bureau 2000). Where Miranda et al. (2007) reported 15.6% of Wayne County housing stock built before 1925, the U.S. Census reported just 7.6% built before 1939 (U.S. Census Bureau 2000). Miranda et al. (2007) were unable to include 25% of records; missing these data could have biased the results. For example, if a higher proportion of the missing children were from Seymour Johnson Air Force Base, which is annexed to the city of Goldsboro and which receives water from the Goldsboro Water System, this could have overestimated the effect of switching to chloramine if the missing children had lower blood lead levels. Children who reside on military bases tend to have lower lead exposures, regardless of the housing stock (Stroop et al. 2002). Miranda et al. (2007) should have considered the possible impact of Hurricane Floyd. The September 1999 hurricane left many homeless; flooding, demolition, and construction activities could well have affected children’s blood lead levels to a greater extent in Goldsboro compared with the rest of Wayne County. Indeed, the raw blood lead level data show an increase county-wide in the year 2000, supporting an effect of the hurricane. The analysis conducted by Miranda et al. (2007) is interesting, and additional studies with individual-level exposure measurements should be conducted. However, their study does not provide a basis for recommending a broad alteration of blood lead screening strategies. States need to do better to ensure that blood lead screening strategies are inclusive, especially for low-income children who are at the greatest risk of undetected elevations in blood lead levels. The recommendation of Miranda et al. (2007) to exclude certain children based on water-disinfection practices could have substantial unintended impacts. In accordance with recommendations of the U.S. Preventive Services Task Force (2007), a more prudent approach to prevent lead exposure via drinking water is that municipalities ensure careful corrosion control and remove lead service lines and distribution pipes, regardless of the method of residual disinfectant used.

Elevated Blood Lead Levels of Children in Guiyu, an Electronic Waste Recycling Town in China

BackgroundElectronic waste (e-waste) recycling has remained primitive in Guiyu, China, and thus may contribute to the elevation of blood lead levels (BLLs) in children living in the local environment.ObjectivesWe compared the BLLs in children living in the e-waste recycling town of Guiyu with those living in the neighboring town of Chendian.MethodsWe observed the processing of e-waste recycling in Guiyu and studied BLLs in a cluster sample of 226 children < 6 years of age who lived in Guiyu and Chendian. BLLs were determined with atomic absorption spectrophotometry. Hemoglobin (Hgb) and physical indexes (height and weight, head and chest circumferences) were also measured.ResultsBLLs in 165 children of Guiyu ranged from 4.40 to 32.67 μg/dL with a mean of 15.3 μg/dL, whereas BLLs in 61 children of Chendian were from 4.09 to 23.10 μg/dL with a mean of 9.94 μg/dL. Statistical analyses showed that children living in Guiyu had significantly higher BLLs compared with those living in Chendian (p < 0.01). Of children in Guiyu, 81.8% (135 of 165) had BLLs > 10 μg/dL, compared with 37.7% of children (23 of 61) in Chendian (p < 0.01). In addition, we observed a significant increasing trend in BLLs with increasing age in Guiyu (p < 0.01). It appeared that there was correlation between the BLLs in children and numbers of e-waste workshops. However, no significant difference in Hgb level or physical indexes was found between the two towns.ConclusionsThe primitive e-waste recycling activities may contribute to the elevated BLLs in children living in Guiyu.

Elevation of Blood Lead Levels in Emergency Department Patients with Extra-articular Retained Missiles

Patients who survive gunshot wounds often have retained missiles. Unlike intra-articular retained missiles, extra-articular retained missiles (EARMs) are not routinely removed. Cases of lead toxicity from EARMs have been described. This study seeks to determine whether blood lead levels are elevated in emergency department patients with EARMs compared with matched controls, whether clinical symptoms of lead toxicity are more prevalent in patients with EARMs than in controls, and whether longer missile retention times or recent hypermetabolic conditions are associated with higher blood lead levels. One hundred twenty adults with EARMs and 120 age- and gender-matched controls with no history of gunshot wound were prospectively enrolled on presentation to a large urban emergency department. Whole blood lead (WBL), zinc protoporphyrin, and hemoglobin levels were obtained. Patients completed a questionnaire regarding time since gunshot injury; symptoms of lead toxicity; and occurrence within 30 days of any surgery, alcohol abuse, illicit drug abuse, diabetic ketoacidosis, hyperthyroidism, infection, fracture, pregnancy, or lactation. Five EARM patients (4%) and no control patients (0%) had WBL greater than our threshold for medical follow-up (20 microg/dL). Mean WBL was 6.71 microg/dL (95% confidence interval [CI], 5.68-7.74 microg/dL) in EARM patients and 3.16 mug/dL (95% CI, 2.79-3.53 microg/dL) in controls. This difference was statistically significant when analyzed by matched pairs t test (p = 0.0001). There was no difference in the number of symptoms associated with lead toxicity that were noted by EARM patients versus controls (p = 0.377). Longer duration of missile retention was not associated with higher blood lead levels (r = 0.125, p = 0.172). Of the five hypermetabolic conditions analyzed, only fractures were associated with elevated blood lead levels (9.95 microg/dL [95% CI, 5.77-14.13 microg/dL] in EARM patients with fractures vs. 6.23 microg/dL [95% CI, 5.23-7.23 microg/dL] in EARM patients without fractures). Patients with EARMs have significantly elevated blood lead levels compared with matched controls. The occurrence of a bony fracture within the past 30 days is associated with a higher lead level. In 96% of patients with EARMs, elevated lead levels were not clinically significant and did not change patient management.

Evaluation of a childhood lead questionnaire in predicting elevated blood lead levels in a rural community.

The accuracy of a lead screening questionnaire in predicting elevated blood lead levels was examined in a pediatric practice in a rural part of New York state. A retrospective chart review was used to collect data on children ages 9 to 24 months who presented for well-child visits. Children with both questionnaire and lead level results available in the chart were included in the study (n = 171). The mean blood lead level among all children was 1.6 microg/dl (median = 2.0 microg/dl, range 0 to 24 microg/dl). Four children (2.3%) had elevated lead levels (greater than 10 microg/dl), with levels for two of these children being greater than 20 microg/dl. Although our lead screening questionnaire was expanded from the standard 1991 CDC questionnaire by the inclusion of six additional items, it was not especially useful in predicting elevated blood lead levels above 10 microg/dl. However, the questionnaire exhibited some utility in predicting marked elevations in blood lead levels (over 20 microg/dl). Although results in other geographic areas might differ, the lead questionnaire may have value by enhancing parents' awareness of potential lead hazards in their children's environment and may prove to be more useful in areas of high risk to lead exposure.

Puzzling elevation of blood lead levels among consumers of freshwater sportfish.

The authors evaluated lead exposure of Canadians (Montreal) who fished the nearby St. Lawrence River. From screening interviews conducted with 1,118 fishers on-site during the winter and fall of 1996, the authors selected 60 Montrealers who consumed at least one sportfish meal per week and 72 who consumed less than one sportfish meal per week. Fishers at the higher level of sportfish consumption had elevated blood lead concentrations, compared with fishers who ate little sportfish (geometric mean = 57.4 microg/l vs. 48.2 microg/l, respectively; p < .05). This result was surprising inasmuch as fish is not considered a significant source of lead. In addition to sportfish consumption, age, sex, occupation, smoking, and waterfowl consumption also showed independent associations with blood lead levels. Among frequent (i.e., > or = 1 meal/wk) consumers of sportfish, ingestion of waterfowl was associated with higher blood lead levels (geometric mean = 69.4 microg/l vs. 51.8 microg/l, respectively; p < .05); this association was not present for infrequent consumers. In multivariate analysis, the association of higher blood lead levels with sportfish consumption could be accounted for in large part by waterfowl consumption among frequent consumers of sportfish.

The Effect of 2, 3 Dimercaptosuccinic Acid in the Treatment of Lead Poisoning in Adults

Four patients, aged 22–60, belonging to a single family that had been exposed to lead-contaminated food for an unknown period, and nine workers, aged 20–65, who had been exposed to air-borne lead for 6–8 years, were evaluated for lead poisoning in our centres. Blood lead levels were 3.57 ± 0.39 μmol/L (mean ± SD) in the family members and 3.46 ± 0.43 μmol/L (mean ± SD) in the group of workers. 2, 3 dimercaptosuccinic acid (DMSA) therapy was instituted in the four family members while the nine workers were closely monitored after being removed from the contaminated environment without receiving any chelation therapy. DMSA therapy given for the duration of 19 days reduced the blood lead levels to 0.63 ± 0.44 μmol/L (mean ± SD), P < 0.01, in the four family members. No significant change was observed in the untreated group. The exposure time in the untreated group was probably longer than that in the treated group. Following long-term exposure most of the lead in the body is found in the bones and therefore not easily removed by chelation therapy. No side-effects were reported in the treated group and no rebound elevation of blood lead levels was observed during the therapy period or during the 12-week follow-up period following cessation of therapy. We conclude that 19 days of chelation therapy with DMSA in adults with moderate to severe lead poisoning is effective and safe.

A Randomized Trial of the Effect of Dust Control on Children's Blood Lead Levels

Dust control is recommended as one of the cornerstones of controlling childhood lead exposure; however, the effectiveness of dust control has not been demonstrated for children who have low to mild elevations in blood lead (ie, less than 25 micrograms/dL). The objective of this study was to determine whether dust control, as performed by families, had an effect on children's blood lead levels and dust lead levels in children's homes. Randomized, controlled trial. Community-based trial in Rochester, NY. One hundred four children, 12 to 31 months of age at baseline. Families and children were randomized to one of two groups. Families of children in the intervention group received cleaning supplies, information about cleaning areas that are often contaminated with lead, and a cleaning demonstration. Families in the control group received only a brochure about lead poisoning prevention. Baseline measurements of lead in blood, house dust, soil, water, and paint were taken from both groups. Seven months after enrollment, a second blood lead assay was obtained, and lead levels in household dust were measured. The main outcome measures were change in blood lead levels and dust lead levels by treatment group. The median blood lead level of children enrolled in the study was 6.7 micrograms/dL (range, 1.7 to 30.6 micrograms/dL). There was no significant difference in the change of children's blood lead levels or dust lead levels by treatment group. The median change in blood lead levels among children in the intervention group was -0.05 micrograms/dL compared with -0.60 micrograms/dL among those in the control group. There also was no significant difference in the change of dust lead by group assignment, although there was a trend toward a significant difference in the percentage of change in dust lead levels on noncarpeted floors, which was greater among houses in the intervention group. These data suggest that an intervention that consists only of providing cleaning supplies and a brief description of dust control is not effective at reducing blood lead levels among urban children with low to mild elevations in blood lead levels at a 7-month follow-up.

Bone Lead Levels and Delinquent Behavior-Reply

In Reply. —Dr Sachs and Dr Sayres are skeptical; they have treated lead-poisoned children but have not observed antisocial behavior. Both relied on personal behavioral observation in a clinic setting; we used structured behavioral inventories from 3 separate informants, all of whom had the benefit of prolonged, close-up observation. Sachs notes that 69 subjects she treated with extreme elevations in blood lead levels (>4.83 μmol/L [>100 μg/dL]) seemed to be doing well on follow-up. She actually treated 105 children with lead levels in this dangerous range, but she ignores 36 subjects who were not located. Subjects not located after treatment generally have worse outcomes than those who are located. It is reasonable to ask how many of her missing lead-poisoned subjects are in special schools, are homeless, are in prison, or are dead. Dr Ernhart criticizes our report because the CBCL delinquency clusters did not reach statistical significance when classified

Chronic oral administration of alkyl lead solutions to the rhesus monkey

The administration of tetraethyl lead (TEL) and tetramethyl lead (TML) to the rhesus monkey for 6 months at the dose level equivalent to 6 μg/kg/day of lead did not induce clinical manifestations of toxicity. Minor elevations in blood lead levels and tissue lead were found in animals receiving tetraethyl lead.