Lead Workers Research Articles

The Relationships Between Blood Pb Levels and Blood Pressure Among Lead-Exposed Workers in China: A Repeated-Measure Study.

To explore the differences in the increase of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in 3 consecutive years among lead (Pb) workers. Four hundred forty-eight Pb workers were enrolled in this repeated-measure study. Blood Pb, SBP, and DBP were measured in 2015 to 2017. Repeated measure of analysis of variance was used to compare the differences in the increase of SBP and DBP. The mean SBP values were 124.0/125.5/126.9 mm Hg, and the mean DBP values were 75.4/77.4/77.8 mm Hg from 2015 to 2017. The differences in the increase of SBP and DBP were 2.94/2.42 mm Hg during the 3-year period. The average annual increase of SBP or DBP showed an upward trend in different Pb dose groups ( F = 4.904, P = 0.002; F = 3.612, P = 0.013). Lead exposure caused average annual increases in SBP and DBP with 0.98 and 0.81 mm Hg, which provided basic data for health surveillance.

Retracted: Statistical Analysis for Identifying Differentially MicroRNA in Serum Exosomes of Lead Workers.

[This retracts the article DOI: 10.1155/2020/8841127.].

P19-16 Correlation between health risks associated with genetic profile and lifestyle in occupationally exposed lead workers

P19-16 Correlation between health risks associated with genetic profile and lifestyle in occupationally exposed lead workers

Reassessment of the threshold of the blood lead level to increase urinary δ-aminolevulinic acid based on their relationship in recent lead workers in Japan.

ObjectivesThe present study investigated the quantitative relationship between blood lead (Pb‐B) and urinary δ⁻aminolevulinic acid (ALA‐U) in lead workers, and examined the Pb‐B level that induces increases in ALA‐U and the corresponding ALA‐U.MethodsWe collected 10 562 data sets on Pb‐B, ALA‐U, age, and smoking habits from 808 workers (771 males and 37 females) who underwent multiple lead poisoning medical examinations at a lead‐acid battery and lead smelting plant in Japan between 1995 and 2018. Females were excluded, and data collected in 169 subjects prior to engaging in lead work were used as the control. Pb‐B and ALA‐U levels were measured by graphite furnace atomic absorption spectrophotometry and high‐performance liquid chromatography respectively.ResultsA significant dose‐response relationship was observed between Pb‐B and ALA‐U based on Pb‐B‐classified observations of increases in ALA‐U values and the prevalence of over‐reference ALA‐U as well as regression analyses independent of smoking habits. The results obtained revealed that the threshold of Pb‐B to increase ALA‐U was 25.1‐35.0 µg/dL based on the significant elevation point of the prevalence of over‐reference ALA‐U and 16.2‐22.3 µg/dL from a 3rd degree regression equation.ConclusionsWe proposed a threshold of Pb‐B to increase ALA‐U of 20 µg/dL and a biologically acceptable value of ALA‐U of 1 mg/L, corresponding to the threshold.

Analysis of neurotransmitters associated with neuropsychiatric status in workers following lead exposure.

To explore the correlation between neuropsychiatric status and blood neurotransmitter in lead workers, and to provide theoretical basis for the prevention and treatment of lead workers. The study applied cross-sectional survey, 74 occupational lead exposed workers in a battery factory in a city of Hebei province were selected as the lead exposed group, and 62 workers (non-lead workers) were selected as the control group. The occupational health symptoms questionnaire and health examination and POMS (Profile of Mood State, POMS) emotional test questionnaire were applied to investigate the nearly emotional status of the studied objects, ICP-MS was used to determine the blood lead level of all subjects, HPLC (High performance liquid chromatography, HPLC) was applied to determine the concentration of neurotransmitter in peripheral blood of all studied subjects, and all results were applied the Pearson's correlation analysis. The blood lead concentration of the lead workers group (163.23±40.77 ug/L) was significantly higher than that in the control group (43.62±14.50 ug/L), and the difference was statistically significant. From the analysis of neuropsychiatric status, the neurological symptoms in the lead workers group were higher than that in the control group, among which the symptoms of sleep disturbance, dizziness, fatigue, numbness of limbs and dampness and coldness of limbs were more obvious. Among the symptoms of digestive system, the incidence of abdominal pain, abdominal distension, constipation and nausea and vomiting were higher. According to the POMS emotion questionnaire, the scores of 5 negative emotions and 1 positive emotion in the lead exposure group were higher than that in the control group, and the difference was statistically significant. Related to the control group, the concentration of neurotransmitters such as DA, 5-HT, GABA, Gly, Trp and Glu were statistically decreased, p<0.001. There was a negative correlation between neurotransmitters in peripheral blood and blood lead levels in lead workers, among which 5-HT had the greatest correlation with lead levels (r=-0.569, p<0.001). 5-HT and Trp were significantly correlated with tension-anxiety (T), depression-depression (D), anger-hostility (A), Vigor-hyperactivity (V), fatigue-inertia (F), and confusion-confusion (C). 5-HT, Trp and GABA were significantly correlated with the survey symptoms, among which, the sleep disorder, constipation and fatigue had most significantly positive correlation with 5-HT or Trp, r-value was respectively 0.373, 0.233 and 0.563. Lead exposure not only causes the alteration of neuropsychiatric behavior of lead workers, but also changes gastrointestinal symptoms. Serotonin may be involved as the main neurotransmitter synthesized in intestinal, and the synthesis and metabolism may be regulated by intestinal flora.

Statistical Analysis for Identifying Differentially MicroRNA in Serum Exosomes of Lead Workers

Exosomes can transmit central nervous system (CNS) information to the peripheral circulatory system through the brain barrier, and exosomes in the blood can also enter the central nervous system likewise. The components of exosomal contents play a pivotal role in cell signal communication, and thus, the transmission of exosomal content components is considered as a newly discovered method of long-distance communication between cells. The current is aimed to explore the changes of the exosomal microRNA group in the serum of lead-exposed workers, which might be involved in the lead-induced neuroinflammation, especially the activation of microglia and the release of inflammatory factors. We proposed a method combining statistical analysis and experiment according to the different expression of exosomal microRNA. Firstly, we divided workers into two groups, lead-exposed group and control group, and then questionnaires were used to obtain their basic information, and medical testing methods were used to obtain their serum exosomes. Secondly, principal component analysis was used to construct a comprehensive index of neurobehavioral function. Furthermore, volcano map and heatmap were used to display the differential gene distribution and correlation analysis of expression levels, respectively. Finally, two software applications, TargetScan and miRanda, were used to predict the target genes of the significantly different microRNAs, respectively, and the target genes predicted by the two software applications are screened according to the scoring standards of each software. Our results showed that 73 microRNAs were changed in the serum exosomes of lead-exposed worker, among which 48 microRNAs are upregulated and 25 microRNAs are downregulated. Moreover, the miR-124 and miR-506 were identified, and they might be involved in the process of lead-induced neuroinflammation.

Use of Generalized Additive Model to Detect the Threshold of δ-Aminolevulinic Acid Dehydratase Activity Reduced by Lead Exposure.

Background: Lead inhibits the enzymes in heme biosynthesis, mainly reducing δ-aminolevulinic acid dehydratase (ALAD) activity, which could be an available biomarker. The aim of this study was to detect the threshold of δ-aminolevulinic acid dehydratase activity reduced by lead exposure. Methods: We collected data on 121 lead workers and 117 non-exposed workers when annual health examinations were performed. ALAD activity was determined by the standardized method of the European Community. ALAD G177C (rs1800435) genotyping was conducted using the polymerase chain reaction and restricted fragment length polymorphism (PCR-RFLP) method. In order to find a threshold effect, we used generalized additive models (GAMs) and scatter plots with smoothing curves, in addition to multiple regression methods. Results: There were 229 ALAD1-1 homozygotes and 9 ALAD1-2 heterozygotes identified, and no ALAD2-2 homozygotes. Lead workers had significantly lower ALAD activity than non-exposed workers (41.6 ± 22.1 vs. 63.3 ± 14.0 U/L, p < 0.001). The results of multiple regressions showed that the blood lead level (BLL) was an important factor inversely associated with ALAD activity. The possible threshold of BLL affecting ALAD activity was around 5 μg/dL. Conclusions: ALAD activity was inhibited by blood lead at a possible threshold of 5 μg/dL, which suggests that ALAD activity could be used as an indicator for lead exposure regulation.

Biological monitoring of urinary lead: Preshift and postshift sampling detects efficiently recent lead exposure and signals the need to review and possibly improve controls at work

The objective of this study is to highlight the effectiveness of urinary lead as an index of recent lead exposure. In the past scientific literature urinary lead has been studied as a parameter for recent lead exposure. It is a reliable indicator for occupational lead exposure. But, strangely enough, nowadays is scarcely used in the Netherlands and worldwide. We performed six field biological monitoring studies of preshift and postshift urinary lead tests during tank maintenance and bridge repair work. Highest values occurred during bridge repair. Mean urinary values were postshift 1,6−5 times higher than preshift values, indicating clearly recent lead exposure and failing protective measures. This is so far we know the first study combining preshift and postshift sampling of urinary lead. We compared our studies with crossectional and follow-up studies in occupational medicine. Our conclusion is that preshift and postshift urinary lead testing is a worker friendly test, ideally for detecting recent lead exposures in the field. It signals the need to review or possibly improve controls at work.There are no safe lead levels, so we recommend to use a target value for urinary lead of <3 μg/g creatinine for all lead workers in the Netherlands.

Evaluation of contrast sensitivity and color vision in lead and zinc mine workers

Purpose. This study was performed to determine achromatic contrast sensitivity and color vision in lead and zinc mine workers. Methods. A total of 230 male workers, who had been working in mine and had been in contact with minerals for at least 1 year, were considered as the case group, and the age of 90 years matched men who have not been in contact with minerals, being regarded as the control group. Contrast sensitivity was assessed using the Freiburg test at three frequencies of 1, 5 and 15 cycles of degree and under low mesopic light condition by two gratings and Landolt C stimuli. Color vision was assessed using the Farnsworth D-15 test under high mesopic light condition. Both tests were carried out monocularly. Data were analyzed using version 22 SPSS software. Results. There was a significant difference between studied groups with Landolt C stimulus in all three frequencies 1, 5 and 15 cycles per degree (p=0.009, p=0.016 and p=0.003). With Grating stimulus, there was a significant difference between the two groups in frequencies of 1 and 15 cycles per degree but at frequency of 5 cycles per degree, there was a border difference (p<0.0001, p=0.051 and p=0.008). A significant difference was observed between color confusion indexes of the two groups (p<0.0001). Conclusion. Chronic exposure to mineral in lead and zinc mine may cause color vision deficiency and decrease in contrast sensitivity. It is recommended that Farnsworth D-15 and Freiburg contrast sensitivity tests would be involved in the early diagnosis of neurodegenerative and visual disorders in workers exposed to minerals.

Leadership skills for strengthening jobsite safety climate

Introduction: Construction foremen may lack the leadership skills needed to create a strong jobsite safety climate. Many construction companies address this by sending their lead workers to the OSHA 30-h course; however the course does not include a leadership training module. This article describes the development and pilot testing of such a module and evaluation surveys designed to address this training gap. Methods: A 17-member curriculum development team, numerous subject matter experts, and an instructional design company helped us develop a comprehensive set of teaching resources and a set of survey instruments for evaluating the materials' effectiveness on improving safety leadership and safety climate. All materials and surveys were pilot tested with representative members of the target population. Results: Pilot surveys showed high reliability and data collected on the resulting Foundations for Safety Leadership (FSL) module indicated that the majority of foremen thought the training was helpful or valuable, particularly the discussion questions. The majority said they intended to use the skills on the jobsite. With the exception of the role-play activities, the trainers rated highly all other components, especially the videos and discussion questions. Modifications were made to the training materials and surveys based on pilot test findings. The most important result of the development and pilot testing efforts is that the OSHA Training Institute (OTI) included the FSL as an elective in the OSHA 30-h course. Conclusions: The FSL module fills a needed skills gap by providing safety leadership training to all foremen who might otherwise not have access to it through their company or union. The continued success of the FSL training will be ensured by dissemination via the OSHA 30-h course, an established nationwide safety training program. Practical applications: The FSL training module has already been widely accepted by the construction industry as a useful approach for providing construction foremen/See new abstract lead workers with the knowledge and skills they need to become more effective jobsite safety leaders.

Oligopolistic suppliers, symbiotic value chains and workers' bargaining power: labour contestation in South China at an ascendant global footwear firm

AbstractIn this article, I analyse changes in the power relationship between lead firms, manufacturers and workers by examining a strike that took place in South China in 2014 among workers at the Taiwanese footwear giant, Yue Yuen. In the process, I demonstrate that there is a link between increased labour costs, capital consolidation and greater value capture at the bottom of the global supply chain. I argue that footwear value chains are seeing a falling level of monopsony power and the emergence of enormous oligopolistic suppliers, which are transforming the power imbalances of global supply chains towards a more mutually dependent ‘buyer–producer symbiosis’. The Yue Yuen strike shows a maturing industrial working class, facing pressures on social reproduction in China, adapting its bargaining strategies vis‐à‐vis the developmental state. Influxes of profit raise the ceiling for what can be demanded of employers, stimulating those same employers to pursue more aggressive means of holding onto their profits. The example of the Yue Yuen strike is an indicator of what are fundamental changes in the production process, dynamics within the value chain, and power and agency of workers in labour‐intensive production. The strike demonstrates that consolidation is playing a decisive role in shaping the power relationship between domestic manufacturers and transnational brands, which, in turn, is directly affecting the bargaining power of workers.

Heart rate variability and peripheral nerve conduction velocity in relation to blood lead in newly hired lead workers

ObjectivesPrevious studies relating nervous activity to blood lead (BL) levels have limited relevance, because over time environmental and occupational exposure substantially dropped. We investigated the association of heart rate variability...

Interactive Effects between Chronic Lead Exposure and the Homeostatic Iron Regulator Transport HFE Polymorphism on the Human Red Blood Cell Mean Corpuscular Volume (MCV).

Research has shown that long-term exposure to lead harms the hematological system. The homeostatic iron regulator HFE (hemochromatosis) mutation, which has been shown to affect iron absorption and iron overload, is hypothesized to be related to lead intoxication in vulnerable individuals. The aim of our study was to investigate whether the HFE genotype modifies the blood lead levels that affect the distributions of serum iron and other red blood cell indices. Overall, 121 lead workers and 117 unexposed age-matched subjects were recruited for the study. The collected data included the blood lead levels, complete blood count, serum iron, total iron binding capacity, transferrin, and ferritin, which were measured during regular physical examinations. All subjects filled out questionnaires that included demographic information, medical history, and alcohol and tobacco consumption. HFE genotyping for C282Y and H63D was determined using polymerase chain reaction and restriction fragment length polymorphism (PCR/RFLP). The mean blood lead level in lead workers was 19.75 µg/dL and was 2.86 µg/dL in unexposed subjects. Of 238 subjects, 221 (92.9%) subjects were wild-type (CCHH) for HFE C282Y and H63D, and 17 (7.1%) subjects were heterozygous for a H63D mutation (CCHD). Multiple linear regression analysis showed that blood lead was significantly negatively associated with hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular volume (MCV), whereas the HFE variant was associated negatively with MCV and positively with ferritin. An interactive influence on MCV was identified between blood lead and HFE variants. Our research found a significant modifying effect of the HFE variant, which possibly affected MCV. The HFE H63D heterozygous (CCHD) variant seemed to provide a protective factor against lead toxicity. Future studies should focus on competing binding proteins between iron and lead influenced by gene variation.

Research Article Human Serum Paraoxonase (PON-1) and hemochromatosis gene (HFE) gene polymorphisms in occupationally exposed lead workers from Saudi Arabia

Research Article Human Serum Paraoxonase (PON-1) and hemochromatosis gene (HFE) gene polymorphisms in occupationally exposed lead workers from Saudi Arabia

Modifying effects of δ-Aminolevulinate dehydratase polymorphism on blood lead levels and ALAD activity

Lead is an environmental hazard with great public health concern and has been known to inhibit delta-aminolevulinate dehydratase (ALAD) activity involved in the heme biosynthetic pathway. The study aimed to investigate the influence of ALAD polymorphism (G177C) on retention of Pb-B levels and ALAD activity on occupationally exposed lead workers. In the present study, we enrolled 561 lead exposed and 317 non-occupationally exposed subjects and performed a comprehensive analysis of Pb-B levels along with ALAD activity and genotyping. The frequency of ALAD variants observed in the total subjects (n = 878) was 70.04% for ALAD 1-1, 27.44% for heterozygous ALAD 1–2 and 2.5% for homozygous mutant ALAD 2-2. Our study revealed that ALAD 1–2 carriers presented higher Pb-B levels compared to wild type ALAD 1-1 carriers. Further, a significant difference was observed in the activity of ALAD between ALAD 1–2/ 2-2 and ALAD 1-1 carriers of non-occupationally exposed group indicating that the polymorphic nature of the enzyme may contribute to altered activity of ALAD irrespective of lead exposure. Hence, ALAD 2 allele might contribute to increased susceptibility to high Pb-B retention, and genotyping of ALAD in lead exposed subjects might be used as a prediction marker to impede tissue/organ damage due to lead toxicity.

Use of Genetic Algorithm Combinational Single-nucleotide Polymorphisms Could Modify the Association of Blood Lead Levels and Bone Matrix Density.

Previous studies have not explored the relationship between a single gene and a single disease. Our study aims to investigate the association of multiple genotypes with blood lead levels and bone matrix density (BMD) by using genetic algorithms. Our research focused on 506 employees (245 males and 261 females) of a lead battery factory in Taiwan. We collected data on their BMD, blood lead level, and 6 SNPs (ACE, alpha-adducin, Bsm, Tag, Apa, and ALAD); these factors were analyzed using discrete binary particle swarm optimization (DBPSO) and logistic regression analysis. We found no association between blood lead level and bone density, which may be due to the relatively young age of this population (mean age = 45.1 years). However, the genotype that contained both Bsm type bb and ALAD type 1-1 may play an important role in protecting against lower bone density among these employees. In conclusion, this study found that the Bsm and ALAD genes influence bone density among lead workers. However, the mechanism and exact relationship between these two genes and bone density require further investigation.

Application of benchmark dose on renal injury in people chronically exposed to lead

Objective: To screen sensitive indicators of renal injury in lead workers using benchmark dose method. Methods: Of the 486 subjects,116 did not occupationally contact to lead as a control. The blood lead was considered as exposure biomarker, while Uβ2-MG and UNAG as effect biomarkers for renal injury. The BMD and BMDL of blood lead were estimated at the 10% benchmark response using BMDS Version 2.6. Results: There was statistical rise in blood lead between the lead group and control group (P<0.05) ; and the blood lead level was divided into four groups by quarterback spacing method, among which UNAG was statistically different (P<0.05) . There was an increased prevalence of abnormal rates of Uβ2-MG and UNAG with increasing blood lead concentration (P<0.05) , after trend chi-square test. BMD and BMDL of UNAG and Uβ2-MG were 602.784/431.838 μg/L and 130.398/100.981 μg/L caculated by Log-Probit model, respectively. Conclusions: Occupational lead exposure may cause kidney damage, and UNAG could be as a more sensitive marker for monitoring early renal injury than Uβ2-MG.

Health-Related Quality of Life of Former Lead Workers in Brazil.

Little is known about the health-related quality of life of former lead workers. Using the Short-Form 36 Questionnaire (SF-36), a cross-section design study evaluated the health-related quality of life of 186 former workers of a lead smelter that operated in Santo Amaro da Purificação, Brazil, from 1960 to 1993, when it closed down. The smelter had very poor occupational and environmental hygiene standards. The health-related quality of life of former lead workers was low, compared to population-based and other nosological groups from Brazil. Former lead workers who indicated metal poisoning, difficulty getting another job and who could not get another job after dismissal by the smelter presented poorer health-related quality of life. Former lead workers with poor health-related quality of life form part of the huge occupational liability left by the Santo Amaro lead smelter.

Lead toxicity.

Since the last In-Depth Review of lead toxicity in 2004 there have been further developments with regard to safe exposure levels for lead workers. To advise occupational health professionals of the latest research on the multi-system toxic effects of lead and the implications of this research for setting new safe and appropriate occupational suspension limits. An extensive review of the current literature and an investigation of the database used by lead users to produce their submission under the REACH Regulations. Much of the published research on lead toxicity is on the effects of lead on the general population where blood lead levels are considerably lower than those seen in lead-exposed workers. It is always difficult to compare such studies with those undertaken on exposed workers as they may not be directly comparable and may not have taken into account all confounding variables and the well-acknowledged 'healthy worker' concept. However, it is clear that there is substantial evidence that potential health effects on lead workers may be seen at levels which were previously accepted as 'safe'. There is undoubtedly a narrow margin of safety between current occupational blood lead suspension limits and subclinical effect. As a result, the lead users have produced a voluntary Code of Practice with suspension limits significantly below those seen in some national legislation, particularly the Control of Lead at Work Act 2002.

Urinary creatinine adjustment for uranium and kidney outcomes from lead workers

Urinary creatinine adjustment for uranium and kidney outcomes from lead workers