Lead absorption and renal dysfunction in a South African battery factory

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Blood Lead Level and Renal Impairment among Adults: A Meta-Analysis

Background: The adult population in lead-related occupations or environmentally exposed to lead may be at risk for renal impairment and lead nephropathy. This meta-analysis aims to determine the impact of blood lead level (BLL) on renal function among middle-aged participants. Methods: Cross-sectional, longitudinal, or cohort studies that reported BLL and renal function tests among adult participants were retrieved from PubMed, Scopus, and ISI Web of Science. Relevant studies were included and assessed for quality using the Newcastle-Ottawa Scale (NOS). The pooled mean BLL of participants with a high BLL (≥30 µg/dL), moderate BLL (20-30 µg/dL), and low BLL (<20 µg/dL) was estimated using the random effects model. The pooled mean differences in BLL, blood urea nitrogen (BUN), creatinine, uric acid, and creatinine clearance between the exposed and non-exposed participants were estimated using the random effects model. Meta-regression was performed to demonstrate the association between the effect size (ES) of the pooled mean BLL and renal function. Heterogeneity among the included studies was assessed using the Cochrane Q and I2 statistics. Cochrane Q with a p value less than 0.05 and I2 more than 50% demonstrated substantial heterogeneity among the studies included. Publication bias was assessed using the funnel plot between the effect size and standard error of the effect size. Results: Out of 1657 articles, 43 were included in the meta-analysis. The meta-analysis demonstrated that the pooled mean BLL in the participants with a high BLL, moderate BLL, and low BLL was 42.41 µg/dL (95% confidence interval (CI): 42.14-42.67, I2: 99.1%), 22.18 µg/dL (95% CI: 21.68-22.68, I2: 60.4%), and 2.9 µg/dL (95% CI: 2.9-2.9, I2: 100%), respectively. The mean BLL of the exposed participants was higher than that of the non-exposed participants (weighted mean difference (WMD): 25.5, p < 0.0001, 95% CI: 18.59-32.45, I2: 99.8%, 17 studies). The mean BUN (WMD: 1.66, p < 0.0001, 95% CI: 0.76-2.55, I2: 76%, 10 studies) and mean creatinine (WMD: 0.05, p = 0.007, 95% CI: 0.01-0.08, I2: 76.8%, 15 studies) in the exposed participants were higher than those in the non-exposed participants. The mean creatinine clearance in the exposed participants was lower than that in the non-exposed participants (standard mean difference (SMD): -0.544, p = 0.03, 95% CI: -1.035-(-0.054), I2: 96.2%). The meta-regression demonstrated a significant positive effect of BLL on BUN (p = 0.022, coefficient: 0.75, constant: -3.7, 10 studies). Conclusions: BLL was observed to be associated with abnormal renal function test parameters, including high BUN, high creatinine, and low creatinine clearance. Moreover, BUN seemed to be the most valuable prognostic marker for lead-induced renal impairment. Therefore, regular checks for renal function among lead-exposed workers should be a priority and publicly promoted.

Activated Carbon Fabric Mask Reduces Lead Absorption and Improves the Heme Biosynthesis and Hematological Parameters of Battery Manufacturing Workers

Activated carbon fabrics (ACF) mask prevents the absorption of lead and reduce its adverse effects of human health. Aim of this study to know the blood lead level and its effects on heme biosynthesis and hematological parameters after using 2 months activated carbon fabric mask of battery manufacturing workers (BMW). Blood lead level, heme biosynthesis and hematological parameters were measured by using standard method. Blood lead level (P < 0.001, - 13.5%) was significantly decreased, activated δ-aminolevulinic acid dehydratase (P < 0.001, 11.97%) and non-activated δ- aminolevulinic acid dehydratase (P < 0.001, 23.17%) enzyme activity were significantly increased, however, the ratio of activated to Non-activated δ- ALAD (P < 0.001, - 10.13%) was significantly decreased, urinary excretion of δ- aminolevulinic acid (P < 0.001, - 10.49%) and porphobilinogen (P < 0.001, - 7.38%) were significantly decreased after using 2 months ACF mask as compared to before using mask of BMW. Hematological parameters i.e Hb (P < 0.05, 13.42%), PCV (P < 0.05, 7.23%), MCV (P < 0.05, 1.9%) were significantly increased and total WBC count (P < 0.05, - 5.18%) was significantly decreased after using 2 months ACF mask as compared to before using mask of BMW. Two months using ACF mask reduces the blood lead level and improves the δ-ALDH activity and hematological parameters, decreases the urinary excretion of δ-ALA, PBG of battery manufacturing workers. Therefore, the regular using of ACF mask is beneficial to prevent the lead absorption and its adverse effects on human health.

The association of blood lead levels and renal effects may be modified by genetic combinations of Metallothionein 1A 2A polymorphisms

Metallothionein (MT) is a protein with function of heavy metal detoxification. However, studies about how single nucleotide polymorphisms (SNPs) of MT genes influence lead nephropathy are relatively scarce. Therefore, our aim is to investigate the association between blood lead levels and renal biomarkers and to study whether this association is influenced by the combination of MT1A and MT2A SNPs. Blood lead, urinary uric acid (UA), and urinary N-acetyl-beta-d-glucosaminidase (NAG) levels were analyzed from 485 participants. Genotyping were performed on MT1A SNPs (rs11640851 and rs8052394) and MT2A SNPs (rs10636 and rs28366003). The combined MT1A 2A SNPs were divided into 16 groups. Among renal biomarkers, urinary UA was negatively significant associated with the time-weighted index of cumulative blood lead (TWICL), while urinary NAG was positively significant with TWICL. Furthermore, the association between urinary UA and TWICL was significantly modified by group 6 of combined SNPs (MT1A 2 A SNPs combination were AAAGGGAA, ACAGGGAA, and ACGGGGAA). In conclusion, the negative association of urinary UA and TWICL is modified by group 6, which means participants of group 6 are more susceptible to lead nephrotoxicity.

Lead, Mercury and Cadmium in Fish and Shellfish from the Indian Ocean and Red Sea (African Countries): Public Health Challenges

The main aim of this review was to assess the incidence of Pb, Hg and Cd in seafood from African countries on the Indian and the Red Sea coasts and the level of their monitoring and control, where the direct consumption of seafood without quality control are frequently due to the poverty in many African countries. Some seafood from African Indian and the Red Sea coasts such as mollusks and fishes have presented Cd, Pb and Hg concentrations higher than permitted limit by FAOUN/EU regulations, indicating a possible threat to public health. Thus, the operationalization of the heavy metals (HM) monitoring and control is strongly recommended since these countries have laboratories with minimal conditions for HM analysis.

Increased blood lead level induces oxidative stress and alters the antioxidant status of spray painters

Background The aim of this study was to know the present scenario of blood lead level and its effect on serum lipid peroxide and antioxidant parameters of spray painters. Methods We included 42 male spray painters and 50 control subjects with an age range of 20-45 years. Blood lead level, serum lipid peroxide and antioxidant parameters, i.e. erythrocyte catalase, superoxide dismutase (SOD), plasma ceruloplasmin, nitric oxide, uric acid and bilirubin, were quantified by standard methods. Results We observed the significant elevated blood lead (p < 0.001, 458%), lipid peroxide (p < 0.001, 170%), uric acid (p < 0.001, 25.6%) and bilirubin (p < 0.01, 24.5%) and the significant decrease in antioxidant enzymes like SOD (p < 0.001, -50.4%), catalase (p < 0.001, -34.33%), ceruloplasmin (p < 0.001, -32.7%) and nitric oxide (p < 0.001, -39.58%) in the study group as compared to control. A significant positive correlation coefficient (r) of blood lead level with lipid peroxide (r = 0.44, p < 0.001), uric acid (r = 0.33 p < 0.05) and bilirubin (r = 0.35, p < 0.05) and a negative correlation with SOD (r = -0.32, p < 0.05), catalase (r = -0.33, p < 0.05), ceruloplasmin (r = -0.27, p < 0.05) and nitric oxide (r = 0.30, p < 0.05) were observed. Conclusions Elevated blood lead level induces serum lipid peroxide and alters the antioxidant enzymes of spray painters. Therefore, it is necessary to reduce the blood lead level by taking proper precautions while spraying the paints, and additional antioxidant supplementation like vitamin C, multivitamin and multiminerals will be useful in reducing oxidative stress.

Chronic Environmental and Occupational Lead Exposure and Kidney Function among African Americans: Dallas Lead Project II

Background: We examined the effects of lead on kidney function in occupationally and environmentally exposed adults from a Dallas lead smelter community that was the site of an Environmental Protection Agency (EPA) Superfund clean-up. All subjects were African Americans—a racial group that bears a disproportionate burden of kidney disease. Methods: A two-phase health screening was conducted. Phase II included a physical examination and laboratory tests. Study subjects were African Americans residents, aged ≥19 years to ≤89 years. Of 778 subjects, 726 were environmentally exposed and 52 were both occupationally and environmentally exposed. The effects of lead exposure on estimated glomerular filtration rate (eGFR) were examined in three groups: male and female smelter-community residents, as well as males with both occupational and environmental exposure. Multiple linear regression was used to analyze the dependence of eGFR on log (blood lead level), duration of residence in the community, type 2 diabetes, and hypertension. Results: There was a statistically significant negative effect on kidney function for all three groups. Comparison of female and male residents showed a slightly larger negative effect of blood lead level on eGFR in females versus males, with the largest effect seen in male smelter-working residents. For each unit increase (log₁₀ 10 µg/dL = 1) in blood lead level, age-adjusted eGFR was reduced 21.2 mL/min/1.73 m² in male residents, 25.3 mL/min/1.73 m² in female residents and 59.2 mL/min/1.73 m² in male smelter-working residents. Conclusions: Chronic lead exposure is associated with worsening kidney function in both African American male and female residents, as well as male workers in Dallas smelter communities. This effect is slightly, but not statistically significantly, worse in female residents than male residents, and significantly worse in males that both worked and resided in the smelter community.

Lead: Tiny but Mighty Poison

The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.

Blood level of cadmium and lead in occupationally exposed persons in Gwagwalada, Abuja, Nigeria

This study was designed to assess the blood levels of cadmium and lead in some occupationally exposed individuals and compare the values with non-exposed individuals, with the aim of increasing the awareness of health risk caused by these heavy metals. A total of 120 subjects (64 occupationally exposed and 56 non-exposed subjects) with the age range of 15–40 years were studied in cross-sectional study conducted between September 2012 and February 2013 in Gwagwalada area of Abuja, Nigeria. Blood cadmium and lead were analyzed using an atomic absorption spectrophotometer (AAS). The respective mean blood levels of cadmium and lead were 11.63±1.73 μg/dl and 45.43±6.93 μg/dl in occupationally-exposed subjects, while in non-exposed subjects 2.03±0.55 μg/dl and 12.08±2.87 μg/dl. The results show that occupational exposure increases the blood level of cadmium and lead, which consequently increases the health risk of the exposed individuals.

Low-level lead exposure changes endothelial modulation in rat resistance pulmonary arteries

Lead exposure induces hypertension and endothelial dysfunction. However, the effects on the pulmonary vasculature have not been explored. In this study, rats exposed to lead acetate for seven days (4μg/100g on the 1st day and 0.05μg/100g/day i.m. subsequently) had lead blood level of 3.9±0.7μg/dL and increased right ventricular pressures. There was an increased Pb deposition and superoxide anions production in the pulmonary arteries, associated with reduced vasoconstriction but unchanged endothelium-dependent vasodilatation to acetylcholine (ACh). In both groups, inhibition of the nitric oxide (NO) synthase with L-NAME blocked the response to ACh, while indomethacin (cycloxygenase inhibitor) had no effect. Incubation with nonspecific potassium channel blocker (tetraethylammonium) reduced the ACh-induced vasodilatation only in the Pb group. Apamin (SKCa channel blocker) and 4-aminopyridine (Kv channel blocker), but not iberiotoxin (BKCa channel blocker), also inhibited this response in the Pb group. The vasodilatation to exogenous NO was reduced by Pb, while relaxation to the cGMP analogue was similar between groups. Concordantly, the protein level of soluble guanylate cyclase (sGC) was reduced. In conclusion, short-term and low-level exposure to Pb changes pulmonary haemodynamic and increases oxidative stress. The pulmonary vasculature exhibited increased hyperpolarization by the Kv and SKCa channels, probably as a compensatory mechanism to the decreased responsiveness to NO.

Association between subchronic and chronic lead exposure and levels of antioxidants and chemokines

Purpose

This study aimed to compare the influence of lead on the non-enzymatic antioxidant defenses and the levels of chemokines in workers subchronically and chronically exposed to lead.

Methods

The study population was divided into three groups. The first group consisted of male workers subchronically exposed to lead for 40 ± 3.2 days, while the second group included male workers chronically exposed to lead. The third group was a control group.

Results

The levels of uric acid and bilirubin were significantly higher after a subchronic exposure to lead compared to the baseline by 22 and 35 %, respectively. Similarly, the values of total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) increased by 15, 50, and 33 %, respectively. At the same time, the levels of thiol groups and albumin decreased by 5 and 8 %, respectively. Additionally, the levels of interleukin-8 (IL-8) and macrophage inflammatory protein-1β (MIP-1β) were significantly higher after a subchronic exposure to lead compared to the baseline by 34 and 20 %, respectively. Moreover, IL-8 level was significantly higher by 40 % in the group of workers chronically exposed to lead than in the control group, while the level of interferon gamma-induced protein-10 (IP-10) was significantly lower by 28 %.

Conclusions

Similar to chronic lead exposure, subchronic exposure to lead is associated with elevated blood levels of uric acid and bilirubin in humans. This probably results in increased TAC value despite thiol depletion. However, the compensatory activation of non-enzymatic antioxidant defenses seems to be insufficient to protect against lead-induced oxidative stress, which may be additively enhanced by the pro-inflammatory action of chemokines, especially IL-8.

Effect of Vitamin C Supplementation on Blood Lead Level, Oxidative Stress and Antioxidant Status of Battery Manufacturing Workers of Western Maharashtra, India

INTRODUCTION

The high blood lead level induces oxidative stress and alters the antioxidant status of battery manufacturing workers. Supplementation of vitamin C is beneficial to reduce the oxidative stress and to improve the antioxidant status of these workers.

AIM

The main aim of this study was to observe the changes in blood lead levels, oxidative stress i.e. serum lipid peroxide and antioxidant status parameters such as erythrocyte superoxide dismutase and catalase and serum nitrite after the vitamin C supplementation in battery manufacturing workers.

MATERIALS AND METHODS

This study included 36 battery manufacturing workers from Western Maharashtra, India, having age between 20-60 years. All study group subjects were provided vitamin C tablets (500 mg/day for one month) and a blood sample of 10 ml each was drawn by puncturing the anterior cubital vein before and after vitamin C supplementation. The biochemical parameters were estimated by using the standard methods.

RESULTS

Blood lead levels were not significantly altered, however, serum lipid peroxide (p<0.001, -15.56%) and serum nitrite (p<0.001, -21.37%) levels showed significant decrease and antioxidant status parameters such as erythrocyte superoxide dismutase (p<0.001, 38.02%) and catalase (p<0.001, 32.36%) revealed significant increase in battery manufacturing workers after the supplementation of vitamin C.

CONCLUSION

One month vitamin C supplementation in battery manufacturing workers is not beneficial to decrease the blood lead levels. However, it is helpful to reduce the lipid peroxidation and nitrite formation and enhances the erythrocytes superoxide dismutase and catalase activity.

The Effects of Lead Exposure on Serum Uric Acid and Hyperuricemia in Young Adult Workers: A Cross-sectional Controlled Study

Objectives

This study aims to evaluate the relationship between serum uric acid levels and renal functions in asymptomatic subjects who had occupational lead exposure, particularly for shorter durations whereby saturnine gout has also been discussed.

Patients and methods

In this retrospective study, files of 100 males (mean age 34.5±5.9 years; range, 21 to 47 years) with occupational risk for lead exposure and 100 healthy male controls (mean age 34.47±5.8 years; range 21 to 47 years) were reviewed. Demographic characteristics of the subjects and laboratory test results were recorded from the files. Creatinine clearance and 24-hour urinary creatinine were measured in the lead-exposed group.

Results

In the lead-exposed group, mean serum uric acid level was higher than those of the control group (p<0.001). Lead exposure time was negatively correlated with 24-hour urinary creatinine levels (r= -0.373, p<0.001). In addition, serum uric acid levels were positively correlated with serum creatinine levels (r=0.412, p<0.001) in the exposed group. Six patients had hyperuricemia (serum uric acid level >6.8 mg/dL) in the lead- exposed group; however, all subjects' serum uric acid level was lower than 6.8 mg/dL in the control group (p=0.029). Although 22 subjects had higher uric acid levels than 6.0 mg/dL in the lead-exposed group, only one control had higher uric acid level than 6.0 mg/dL (p<0.001).

Conclusion

In light of our results, we may conclude that workers with lead exposure have higher frequency of hyperuricemia and higher serum uric acid levels than those of the control group. Therefore, we may imply that higher serum uric acid levels may be associated with renal impairment in lead-exposed subjects even in the earlier stages of exposure.

Occupational exposures and chronic kidney disease: Possible associations with endotoxin and ultrafine particles

BACKGROUND

Chronic kidney disease (CKD) carries a high public health burden yet there is limited research on occupational factors, which are examined in this retrospective case-control study.

METHODS

Newly diagnosed cases of CKD (n = 547) and controls (n = 508) from North Carolina provided detailed work histories in telephone interviews. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

There was heterogeneity in the association of CKD and agricultural work, with crop production associated with increased risk and work with livestock associated with decreased risk. Work with cutting/cooling/lubricating oils was associated with a reduced risk. CKD risk was increased for working in dusty conditions.

CONCLUSIONS

CKD risk was reduced in subjects with occupational exposures previously reported to involve endotoxin exposure. Further, exposure to dusty conditions was consistently associated with increased risk of glomerulonephritis across industry, suggesting that research on CKD and ultrafine particulates is needed.

The Effects of Lead Exposure on Serum Uric Acid and Hyperuricemia in Chinese Adults: A Cross-Sectional Study

The aim of this study was to assess the correlation between blood lead levels and both serum uric acid and hyperuricemia in adult residents living within an area of China with lead pollution.  We conducted a cross-sectional analysis of 2120 subjects (1180 of whom were male) between the ages of 20 and 75 years who had undergone health examinations at the Centers for Disease Control and Prevention (CDC) in a lead-polluted area of China between January 2013 and August 2014. Blood lead was positively correlated with serum uric acid in both males (r = 0.095, p = 0.001) and females (r = 0.134, p < 0.001). Multivariate linear regression analysis demonstrated that for males, blood lead (p = 0.006), age (p = 0.001), current smoking (p = 0.012), education (p = 0.001), triglycerides (TG) (p < 0.001), and serum creatinine (p < 0.001) were independently associated with serum uric acid. For females, blood lead (p < 0.001), body mass index (BMI) (p = 0.009), and TG (p < 0.001) were independently associated with serum uric acid. After multiple adjustments, blood lead was significantly associated with a higher prevalence of hyperuricemia when female subjects were categorized into quartiles (for the highest quartile vs. the lowest quartile, odds ratio (OR) = 2.190; 95% confidence interval (CI): 1.106–4.338; p = 0.025); however, no such association was observed for male subjects. Continuous lead exposure has an independent impact on serum uric acid for both males and females, although this impact is more pronounced for females than for males. Lead exposure is significantly associated with hyperuricemia for females but not for males.

Comparative evaluation of essential and toxic elements in the blood of kidney failure patients and healthy referents

The aim of the present study was to evaluate the comparative distribution, correlation, and apportionment of selected elements-aluminum (Al), calcium (Ca), cadmium (Cd), potassium (K), magnesium (Mg), sodium (Na), and lead (Pb)-in the blood samples of male kidney failure patients (KFP) and healthy subjects of age ranged 30-60 years. The blood samples were digested with nitric acid and perchloric acid mixture (2:1), followed by the quantification of elements by atomic absorption spectrometry. The concentration of essential elements in blood samples of KFP were found in the range of Ca (97-125), Mg (18-36), Na (2971-3685), and K (177-270) mg/L while, the levels of Al, Cd, and Pb were found in the range of (475-1275), (0.9-9.9), and (211-623) μg/L, respectively. In the healthy referents, concentration of electrolytes in blood samples was lower than KFP, but difference was not significant (p > 0.05). While the levels of toxic elements in blood samples of referents were three- to sixfold lower than KFP (p < 0.01). Principal component analysis (PCA) and cluster analysis (CA) of the element data manifested diverse apportionment of the selected elements in the blood sample of the KFP compared with the healthy counterparts.

Towards the prevention of lead exposure in South Africa: contemporary and emerging challenges

The prevention of lead exposure continues to constitute a major public health challenge in developed countries. In well-resourced countries major lead exposure reduction interventions have resulted in significant improvements in childhood blood lead distributions. In developing countries on the other hand, while lead exposure and poisoning remain serious public health concerns, a range of prevailing factors and circumstances, such as poverty, a large informal sector, competing public health challenges, low levels of awareness of lead hazards and weak capacity to enforce legislation, contribute to an increase in the scale and intensity of the challenge, and limit the prospects of comparable success in the foreseeable future. This paper collates available information to illustrate that despite some progress, a wide range of sources of lead exist in South Africa, and that certain settings and groups continue to be at high risk of lead exposure. Lead exposure in relation to paint, mining, lead melting in subsistence fishing communities, the consumption of Ayurvedic medicines and food production is described, and discussed with regard to the key factors hindering efforts to prevent lead poisoning and exposure in South Africa and many other developing countries.

A polymorphism in AGT and AGTR1 gene is associated with lead-related high blood pressure

We investigated the association of polymorphisms in two renin-angiotensin system-related genes, expressed as angiotensinogen (AGT) and angiotensin II type 1 receptor (AGTR1), with blood lead levels and lead-related blood pressure in lead-exposed male workers in Korea. A cross-sectional study involving 808 lead-exposed male workers in Korea was conducted using a restriction fragment length polymorphism-based strategy to differentiate the various genotypes of polymorphisms in the AGT and AGTR1 genes. The association of clinical characteristics with genotypes as modifiers was estimated after adjustment for age, smoking status, drinking status, body mass index and job duration of each subject. Genotype and allele frequencies of the M235T polymorphism in AGT were associated with lead-related high blood pressure status. Moreover, blood lead levels were associated with allele frequencies of the AGT M235T polymorphism. These results suggested that the M/M genotype and M allele of AGT are risk factors for lead-related high blood pressure.

Ameliorating activity of ginger (Zingiber officinale) extract against lead induced renal toxicity in male rats

Lead poisoning has been known to be associated with structural and functional abnormalities of multiple organ systems of human body. The aim of this investigation was to study the renal protective effects of ginger (Zingiber officinale) extract in lead induced toxicity rats. In this study renal glutathione (GSH) level, glutathione peroxidase (GPX), glutathione-s-transferase (GST), and catalase enzymes were measured in lead nitrate (300 mg/kg BW), and lead nitrate plus ginger extract (150 mg/kg BW) treated rat groups for 1 week and 3 weeks respectively. The glutathione level and GSH dependent antioxidant enzymes such as glutathione peroxidase, glutathione-s-transferase, and catalase significantly (P < 0.05) increased in ginger extract treated rat groups. In addition, histological studies showed lesser renal changes in lead plus ginger extract treated rat groups than that of lead alone treated rat groups. These results indicate that ginger extract alleviated lead toxic effects by enhancing the levels of glutathione, glutathione peroxidase, glutathione-s-transferase and catalase.

Lead Nephropathy: Revisiting an Overlooked Cause of Kidney Disease

Despite the recognition of lead nephropathy as a consequence of environmental and occupational lead exposure, lead nephropathy still appears to be underrecognized by physicians as a cause and promoter of chronic kidney disease (CKD), especially in people with more apparent causative factors such as diabetes and hypertension. This review focuses on the clinical, pathophysiological and epidemiological perspectives of lead nephropathy with the objective of promoting the awareness of this important but overlooked cause of CKD among physicians. Literature was reviewed using available medical journals and online literature search through Google, Pubmed, Medline, Medscape and HINARI databases. The key words employed were: Lead Nephropathy, Environmental and Occupational lead exposure and chronic kidney disease. Lead nephropathy which is a tubulointerstitial nephritis, may present acutely or chronically in association with hypertension. The clinical diagnosis of lead nephropathy is complex, because the symptoms are varied and non-specific especially with subclinical nephrotoxicity. The recognition of lead nephropathy can be enhanced if physicians have a high index of suspicion in the assessment of patients with renal disease. It is recommended that the evaluation of environmental and occupational nephrotoxins like lead be incorporated into programs for the prevention of CKD, especially in developing countries where lead exposure and toxicity still remain largely unchecked and the prevalence and burden of CKD is increasing.

Low-dose chronic lead exposure increases systolic arterial pressure and vascular reactivity of rat aortas

Chronic lead exposure induces hypertension affecting endothelial function. We investigated whether low-concentration lead exposure alters blood pressure and vascular reactivity, focusing on the roles of NO, oxidative stress, cyclooxygenase-derived vasoconstrictor prostanoids, and the local angiotensin-renin system. Aortic rings from 3-month-old Wistar rats were treated daily with lead acetate (first dose 4mg/100g, subsequent doses 0.05mg/100g, im) or vehicle for 30 days. Treatment increased lead blood levels (12μg/dl), blood pressure, and aortic ring contractile response to phenylephrine (1nM-100mM). Contractile response after L-NAME administration increased in both groups but was higher after lead treatment. Lead effects on Rmax decreased more after apocynin and superoxide dismutase administration compared to control. Indomethacin reduced phenylephrine response more after lead treatment than in controls. The selective COX-2 inhibitor NS398, thromboxane A2/prostaglandin H2 receptor antagonist SQ 29,548, TXA2 synthase inhibitor furegrelate, EP1 receptor antagonist SC 19220, and ACE inhibitor and AT1 receptor antagonist losartan reduced phenylephrine responses only in vessels from lead-treated rats. Basal and stimulated NO release was reduced and local O2(-) liberation increased in the lead-treated group compared to controls. eNOS, iNOS, and AT1 receptor protein expression increased with lead exposure, but COX-2 protein expression decreased. This is the first demonstration that blood Pb(2+) (12µg/dl) concentrations below the WHO-established values increased systolic blood pressure and vascular phenylephrine reactivity. This effect was associated with reduced NO bioavailability, increased reactive oxygen species production, increased participation of COX-derived contractile prostanoids, and increased renin-angiotensin system activity.

Effect of vitamin E and C supplementation on oxidative damage and total antioxidant capacity in lead-exposed workers

The molecular response of the antioxidant system and the effects of antioxidant supplementation against oxidative insult in lead-exposed workers has not been sufficiently studied. In this work, antioxidants (vitamin E 400 IU+vitamin C 1g/daily) were supplemented for one year to 15 workers exposed to lead (73 μg of lead/dl of blood) and the results were compared with those on 19 non-lead exposed workers (6.7 μg of lead/dl). Lead intoxication was accompanied by a high oxidative damage and an increment in the erythrocyte antioxidant response due to increased activity of catalase and superoxide dismutase. Antioxidant supplementations decreased significantly the oxidative damage as well as the total antioxidant capacity induced by lead intoxication with reduction of the antioxidant enzyme activities. We conclude that antioxidant supplementation is effective in reducing oxidative damage and induces modifications in the physiopathological status of the antioxidant response in lead-exposed workers.

Association between Blood Lead Level and Blood Pressure in Aborigines and Others in Central Taiwan

To investigate the relationship between the blood lead level (BLL) and blood pressure among aborigines and non-aborigines in central Taiwan, a community-based survey that included demographic data, medical history, and blood chemistry analyses was conducted among 2,565 adults during an annual health examination. BLLs were analyzed using a graphite furnace atomic absorption spectrometer (AAS). There was a dose response among the non-aborigines (high BLL odds ratio = 2.97, compared with low BLL) but not among aborigines. Based on multiple linear regression models, BLLs were positively correlated with both systolic (an increase of 0.85 mm Hg/microg/dL) and diastolic (an increase of 0.48 mm Hg/microg/dL) blood pressures after adjusting for age, gender, ethnic group, alcohol consumption, and body mass index. BLLs were higher among aborigines than non-aborigines and were significantly correlated with blood pressure, particularly systolic pressure. The association should be considered causal.

The relationship between blood lead levels and morbidities among workers employed in a factory manufacturing lead-acid storage battery

The present study was carried out to find the relationship between blood lead levels (BLLs) and morbidities among 391 male workers employed in a factory manufacturing lead-acid storage batteries. A predesigned questionnaire was used to collect information on subjective health complaints and clinical observation made during a clinical examination. In addition to monitoring of BLL, other laboratory parameters investigated included hematological and urine-δ-aminolevulinic acid levels. Logistic regression method was used to evaluate the relationship between BLL and morbidities. The BLL among workers was associated with an odd ratio of respiratory, gastrointestinal (GI), and musculoskeletal (MSD) morbidities. Mean corpuscular hemoglobin and packed cell volume variables were associated with respiratory problems. The variables of alcohol consumption and hematological parameters were associated with GI complaints. Systolic blood pressure was related to MSD in workers exposed to Pb during the manufacturing process.

Review: Lead exposure in battery manufacturing and recycling in developing countries and among children in nearby communities

The battery industry is the largest consumer of lead, using an estimated 80% of the global lead production. The industry is also rapidly expanding in emerging market countries. A review of published literature on exposures from lead-acid battery manufacturing and recycling plants in developing countries was conducted. The review included studies from 37 countries published from 1993 to 2010 and excluded facilities in developed countries, such as the United States and those in Western Europe, except for providing comparisons to reported findings. The average worker blood lead level (BLL) in developing countries was 47 μg/dL in battery manufacturing plants and 64 μg/dL in recycling facilities. Airborne lead concentrations reported in battery plants in developing countries averaged 367 μg/m3, which is 7-fold greater than the U.S. Occupational Safety and Health Administration's 50 μg/m3 permissible exposure limit. The geometric mean BLL of children residing near battery plants in developing countries was 19 μg/dL, which is about 13-fold greater than the levels observed among children in the United States. The blood lead and airborne lead exposure concentrations for battery workers were substantially higher in developing countries than in the United States. This disparity may worsen due to rapid growth in lead-acid battery manufacturing and recycling operations worldwide. Given the lack of regulatory and enforcement capacity in most developing countries, third-party certification programs may be the only viable option to improve conditions.

Toxic effects of mercury, lead and gadolinium on vascular reactivity

Heavy metals have been used in a wide variety of human activities that have significantly increased both professional and environmental exposure. Unfortunately, disasters have highlighted the toxic effects of metals on different organs and systems. Over the last 50 years, the adverse effects of chronic lead, mercury and gadolinium exposure have been underscored. Mercury and lead induce hypertension in humans and animals, affecting endothelial function in addition to their other effects. Increased cardiovascular risk after exposure to metals has been reported, but the underlying mechanisms, mainly for short periods of time and at low concentrations, have not been well explored. The presence of other metals such as gadolinium has raised concerns about contrast-induced nephropathy and, interestingly, despite this negative action, gadolinium has not been defined as a toxic agent. The main actions of these metals, demonstrated in animal and human studies, are an increase of free radical production and oxidative stress and stimulation of angiotensin I-converting enzyme activity, among others. Increased vascular reactivity, highlighted in the present review, resulting from these actions might be an important mechanism underlying increased cardiovascular risk. Finally, the results described in this review suggest that mercury, lead and gadolinium, even at low doses or concentrations, affect vascular reactivity. Acting via the endothelium, by continuous exposure followed by their absorption, they can increase the production of free radicals and of angiotensin II, representing a hazard for cardiovascular function. In addition, the actual reference values, considered to pose no risk, need to be reduced.

Low-level lead exposure increases systolic arterial pressure and endothelium-derived vasodilator factors in rat aortas

Chronic lead exposure induces hypertension and alters endothelial function. However, treatment with low lead concentrations was not yet explored. We analyzed the effects of 7 day exposure to low lead concentrations on endothelium-dependent responses. Wistar rats were treated with lead (1st dose 4 µg/100 g, subsequent dose 0.05 µg/100 g, i.m. to cover daily loss) or vehicle; blood levels attained at the end of treatment were 9.98 µg/dL. Lead treatment had the following effects: increase in systolic blood pressure (SBP); reduction of contractile response to phenylephrine (1 nM–100 µM) of aortic rings; unaffected relaxation induced by acetylcholine (0.1 nM–300 µM) or sodium nitroprusside (0.01 nM–0.3 µM). Endothelium removal, N^G-nitro-L-arginine methyl ester (100 µM) and tetraethylammonium (2 mM) increased the response to phenylephrine in treated rats more than in untreated rats. Aminoguanidine (50 µM) increased but losartan (10 µM) and enalapril (10 µM) reduced the response to phenylephrine in treated rats. Lead treatment also increased aortic Na⁺/K⁺-ATPase functional activity, plasma angiotensin-converting enzyme (ACE) activity, protein expression of the Na⁺/K⁺-ATPase alpha-1 subunit, phosphorylated endothelial nitric oxide synthase (p-eNOS), and inducible nitric oxide synthase (iNOS). Our results suggest that on initial stages of lead exposure, increased SBP is caused by the increase in plasma ACE activity. This effect is accompanied by increased p-eNOS, iNOS protein expression and Na⁺/K⁺-ATPase functional activity. These factors might be a compensatory mechanism to the increase in SBP.

Chronic renal failure from lead: myth or evidence-based fact?

In this mini review, we would like to challenge the well-established 'fact' that lead exposure causes chronic renal failure (CRF). Even though only scarce evidence exists of the relationship between lead and renal failure, a World Health Organization Environmental Health Criteria document summarizes that 'Lead has been a very common cause of acute or chronic renal failure'. It is also written and cited in textbooks and numerous publications that chronic lead nephropathy causes a slowly progressive interstitial nephritis manifested by a reduced glomerular filtration rate, and that there is a growing consensus that lead contributes to hypertension in the general population. We will argue that, when published reports are carefully scrutinized, such statements on lead and CRF are not evidence based but are rather founded on a few narrative reports on lead-exposed individuals and statistical associations between lead and serum creatinine (or urea) in a few population studies. We will, however, not argue that lead is not toxic and that lead does not cause other types of severe health effects where the evidence is unquestionable, but we do not believe that the kidneys are an early victim after lead exposure.

Effects of occupational lead exposure on renal and nervous system of workers of traditional tile factories in Mashhad (northeast of Iran)

Occupational lead poisoning is a health problem in Iran. Renal and neuropsychiatric complications of occupational lead poisoning are the main concerns for the workers and their employers. It was thus aimed to investigate the renal and neurotoxic effects of lead poisoning in the workers of two traditional-tile-factories. Researchers visited the workers in the factories and collected data by taking direct history and physical examinations in summer of 2005. Data were recorded in previously designed forms. Blood and urine lead concentrations were measured by an atomic absorption technique. A neurologist examined all workers and electrophysiological investigations were undertaken as clinically indicated. Data were analyzed by SPSS software and chi-square, student t test and Pearson correlation tests were used accordingly. The numerical data were expressed as mean ± standard deviation and p < 0.05 was considered as the significant level. Overall, 108 male subjects aged 37 ± 7.8 years were studied. Duration of lead exposure was 9.8 ± 6 years. Lead concentration in 2005 was 361.5 ± 176.9 μg/L. The main objective clinical findings were lead line (64.8%), peripheral neuropathy of upper limb (37%), suppression of deep tendon reflexes (DTR) in upper limbs (25.7%), tremor (23.3%), peripheral neuropathy of lower limbs (17%) and abdominal tenderness (15.1%). The subjective findings were mainly on the central nervous system, such as loss of memory (57%), moodiness (56.1%), agitation (47.7%), drowsiness (36.4%), and headache (29.9%). There was no significant correlation between blood lead concentration and glomerular filtration rate (GFR). But there were significant correlations between the blood lead concentrations and urine lead concentration (p < 0.001). This study showed that lead had toxic effects on the teeth (bone), central and peripheral nervous system, more than renal function. Prophylactic and treatment measures were performed.

Estimation of toxic metals in scalp hair samples of chronic kidney patients

The determination of toxic metals (TMs) in the biological samples of human beings is an important clinical screening procedure. The aim of this work is to determine total content of TMs, aluminum (Al), cadmium (Cd), nickel (Ni), and lead (Pb) in scalp hair samples of chronic kidney male patients (CKPs) on maintenance hemodialysis, during the period of 2005-2007. The study included 115 CKPs (all smokers) and 150 controls or referents [82 (nonsmokers) and 68 (smokers)]. Both controls and patients (males) were of the same age group (ranged 25-55 years), socioeconomic status, localities, and dietary habits. The scalp hair samples were analyzed by electrothermal atomic absorption spectrometer, prior to microwave-induced acid digestion. The accuracy of the total Al, Cd, Ni, and Pb measurements was tested by simultaneously analyzing certified reference material (human hair NCS ZC81002). No significant differences were observed between the analytical results and the certified values (paired t test at p > 0.05). The levels of TMs in scalp hair samples of patients were found to be higher as compared to control nonsmoker and smokers. Moreover, the study shows that levels of Al, Cd, Ni, and Pb in scalp hair samples may be useful to evaluate the impact of cigarette smoking in kidney failure patients.

Lead, at low levels, accelerates arteriolopathy and tubulointerstitial injury in chronic kidney disease

Chronic lead exposure has been epidemiologically linked with hypertension and renal disease. Clinical studies suggest that low lead levels may contribute to renal progression. However, experimental studies have not examined whether low levels of lead accelerate progression in experimental chronic renal disease. Sprague-Dawley rats were administered lead (L; 150 ppm in drinking water, n = 16) for 4 wk, followed by remnant kidney (RK) surgery with continuation of lead for an additional 12 wk; control rats (n = 9) were treated similarly but did not receive lead. Lead treatment was well tolerated and resulted in modest elevations in whole blood lead levels (26.4 +/- 4.5 vs. 1 +/- 0 mug/dl, week 16, P < 0.001). Lead treatment was associated with higher systolic blood pressure (P < 0.05) and worse renal function (creatinine clearance 1.4 +/- 0.4 vs. 1.8 +/- 0.5 ml/min, RK+L vs. RK, P < 0.05), and with a tendency for greater proteinuria (6.6 +/- 6.1 vs. 3.6 +/- 1.5 mg protein/mg creatinine, RK+L vs. RK, P = 0.08). While glomerulosclerosis tended to be worse in lead-treated rats (37.6 +/- 11 vs. 28.8 +/- 2.3%, RK+L vs. RK, P = 0.06), the most striking finding was the development of worse arteriolar disease (P < 0.05), peritubular capillary loss (P < 0.05), tubulointerstitial damage, and macrophage infiltration (P < 0.05) in association with significantly increased renal expression of monocyte chemoattractant protein-1 mRNA. In conclusion, lead accelerates chronic renal disease, primarily by raising blood pressure and accelerating microvascular and tubulointerstitial injury.

Lead-related nephrotoxicity: a review of the epidemiologic evidence

Chronic kidney disease (CKD) represents a major global public health concern. Efforts to prevent and/or slow progression of CKD are essential. Lead nephropathy, characterized by chronic tubulointerstitial nephritis, is a well-known risk of chronic, high-level lead exposure. However, in recent years, lead exposure has declined sharply, particularly in developed countries. We reviewed epidemiologic research in general, occupational, and patient populations to assess whether lead, at current exposure levels, still contributes to nephrotoxicity. Other pertinent topics, such as risk in children, genetic susceptibility, and co-exposure to cadmium, are also considered. The data reviewed indicate that lead contributes to nephrotoxicity, even at blood lead levels below 5 microg/dl. This is particularly true in susceptible populations, such as those with hypertension (HTN), diabetes, and/or CKD. Low socioeconomic status is a risk factor for both lead exposure and diseases that increase susceptibility. Future public health risk for lead-related nephrotoxicity may be most significant in those rapidly developing countries where risk factors for CKD, including obesity and secondary HTN and diabetes mellitus, are increasing more rapidly than lead exposure is declining. Global efforts to reduce lead exposure remain important. Research is also needed to determine whether specific therapies, such as chelation, are beneficial in susceptible populations.

Assessment of lead exposure risk in locksmiths

Exposure to lead has been well recognized in a number of work environments, but little is known about lead exposure associated with machining brass keys containing lead. The brass that is widely used for key manufacturing usually contains 1.5% – 2.5 % of lead. Six (6) licensed locksmiths and 6 case-matched controls successfully completed the pilot study to assess the prevalence of increased body lead burden of professional locksmiths. We measured both Blood Lead (atomic absorption spectrometry), bone-lead (KXRF) and had each subject complete a health and lead exposure risk questionnaire. One locksmith had not cut keys during the past two years, therefore this subject and case-matched control was excluded from the blood lead analysis only. The average blood-lead concentration (±SEM) for the 5 paired subjects was 3.1 (± 0.4) μg/dL and 2.2 (± 0.3) μg /dL for controls. Bone measurements, including all 6 paired subjects, showed tibia lead concentration (±SEM) for locksmiths and controls was 27.8 (± 2.3) μg /g and 13.7 (± 3.3) μg /g, respectively; average calcaneus lead concentration for locksmiths and controls was 31.9 (± 3.7) μg /g and 22.6 (± 4.1) μg /g, respectively: The t-test shows a significantly higher tibia lead (p<0.05) and blood lead (p<0.05) for locksmiths than for their matched controls, but no significant difference for calcaneus lead (p>0.10). Given that the mean tibia bone lead concentration was 13.1μg/g higher in locksmiths than in their matched controls, this average difference in the two groups would translate to an OR of increased hypertension in locksmiths of between 1.1 and 2.3, based on the published literature. Even with the very small number of subjects participating in this pilot study, we were able to demonstrate that locksmiths had significantly higher current exposure to lead (blood lead concentration) and significantly higher past exposure to lead (tibia lead concentration) than their age, sex and ethnically matched controls. Additional research is needed to fully identify the prevalence and associated risk factors for occupational exposure of lead in this previously understudied profession.

Lead blood concentrations and renal function evaluation: study in an exposed Mexican population

The relation of blood Pb concentrations and renal dysfunction has been reported in association with interstitial fibrosis, tubular atrophy, and decreased glomerular filtration. In this report information about blood Pb concentrations and renal function tests in a population from Oaxaca, Mexico is analyzed. The main changes found were that males had higher blood Pb concentrations than females (P<0.0012); the leading variables associated with this were occupation (glazed pottery workers, P=0.0001) and the use of glazed pottery for preparing meals (P=0.0000). Variables that better explain uric acid variability were blood Pb concentrations, sex, weight, and height (r2=0.23). Hyperuricemia was associated with blood Pb concentrations above 40 microg/dL (OR=1.74, 95% CI, 1.12-2.61). SCr was associated with sex, age, and blood Pb, with coefficient r2=0.12. Our findings might be related to inadequate control of oven emissions, a situation that will require further analysis and the implementation of preventive measurements for the nonoccupational exposed population.

Lead in finger bone, whole blood, plasma and urine in lead-smelter workers: extended exposure range

OBJECTIVES

To assess the historical exposure and to study the relationships between lead concentrations in whole blood (B-Pb), plasma (P-Pb), urine (U-Pb), finger bone (Bone-Pb) and duration of employment in workers at a secondary lead smelter and to compare the relationships between B-Pb and P-Pb with results from previous studies of populations with a wide range of lead exposure.

METHODS

In 39 lead workers (29 active, ten retired), recruited from those with the highest exposure at a German secondary lead smelter, levels of B-Pb, P-Pb and U-Pb were determined by inductively coupled plasma mass spectrometry (ICP-MS). Bone-Pb was determined by in vivo X-ray fluorescence (XRF). Results were compared with data from a previous study on 90 workers (71 active, 19 retired) with lower exposure, from a Swedish secondary lead smelter, as well as with previously collected data from 42 active Russian lead workers and 34 Ecuadorian lead-exposed subjects.

RESULTS

The median values in the active/retired German lead workers were: age 44/59 years, duration of employment 20/38 years, Bone-Pb 71/150 microg/g, B-Pb 500/330 microg/l, P-Pb 2.7/1.1 microg/l, and U-Pb 25/13 micromol/mol creatinine. Bone-Pb increased with duration of employment by 4.2 microg/g per year and 1.6 microg/g per year in German and Swedish workers, respectively. The median Bone-Pb was three times higher in both active and retired German workers than in Swedish smelter workers with essentially the same age distribution and duration of employment. The linear regression equation between B-Pb and log P-Pb in the combined group of Ecuadorian, German, Russian and Swedish lead-exposed subjects (n=176) was B-Pb=545 x log[P-Pb] + 258 (r(s)=0.94; P<0.001).

CONCLUSIONS

The high Bone-Pb values recorded for the German smelters implied a historical lead exposure of considerable magnitude. The long-term high lead exposure also showed up in the B-Pb levels for both active and retired workers, leading to the implementation of necessary industrial safety measures in order to respond to biological threshold limits. The suggested equation describing the relationship between B-Pb and P-Pb in the combined group of subjects with a wide range of lead exposure can be useful in future cross-sectional and longitudinal studies of lead-exposed populations, relating, e.g., lead exposure to adverse health outcomes.

Associations among lead dose biomarkers, uric acid, and renal function in Korean lead workers

Recent research suggests that both uric acid and lead may be nephrotoxic at lower levels than previously recognized. We analyzed data from 803 current and former lead workers to determine whether lead biomarkers were associated with uric acid and whether previously reported associations between lead dose and renal outcomes were altered after adjustment for uric acid. Outcomes included uric acid, blood urea nitrogen, serum creatinine, measured and calculated creatinine clearances, and urinary N-acetyl-ss-d-glucosaminidase (NAG) and retinol-binding protein. Mean (+/- SD) uric acid, tibia lead, and blood lead levels were 4.8 +/- 1.2 mg/dL, 37.2 +/- 40.4 microg/g bone mineral, and 32.0 +/- 15.0 microg/dL, respectively. None of the lead measures (tibia, blood, and dimercaptosuccinic-acid-chelatable lead) was associated with uric acid, after adjustment for age, sex, body mass index, and alcohol use. However, when we examined effect modification by age on these relations, both blood and tibia lead were significantly associated (ss = 0.0111, p < 0.01 and ss = 0.0036, p = 0.04, respectively) in participants in the oldest age tertile. These associations decreased after adjustment for blood pressure and renal function, although blood lead remained significantly associated with uric acid (ss = 0.0156, p = 0.01) when the population was restricted to the oldest tertile of workers with serum creatinine greater than the median (0.86 mg/dL). Next, in models of renal function in all workers, uric acid was significantly (p < 0.05) associated with all renal outcomes except NAG. Finally, in the oldest tertile of workers, associations between lead dose and NAG were unchanged, but fewer associations between the lead biomarkers and the clinical renal outcomes remained significant (p less than or equal to 0.05) after adjustment for uric acid. In conclusion, our data suggest that older workers comprise a susceptible population for increased uric acid due to lead. Uric acid may be one, but not the only, mechanism for lead-related nephrotoxicity.

Associations of lead biomarkers with renal function in Korean lead workers

AIMS

To compare associations of lead biomarkers with renal function in current and former lead workers.

METHODS

Cross sectional analysis of first year results from a longitudinal study of 803 lead workers and 135 controls in South Korea. Clinical renal function was assessed by blood urea nitrogen (BUN), serum creatinine, and measured and calculated creatinine clearance. Urinary N-acetyl-beta-D-glucosaminidase (NAG) and retinol-binding protein were also measured.

RESULTS

Mean (SD) tibia lead, blood lead, and DMSA chelatable lead levels in lead workers were 37.2 (40.4) micro g/g bone mineral, 32.0 (15.0) micro g/dl, and 767.8 (862.1) micro g/g creatinine, respectively. Higher lead measures were associated with worse renal function in 16/42 models. When influential outliers were removed, higher lead measures remained associated with worse renal function in nine models. An additional five associations were in the opposite direction. Effect modification by age was observed. In 3/16 models, associations between higher lead measures and worse clinical renal function in participants in the oldest age tertile were significantly different from associations in those in the youngest age tertile which were in the opposite direction. Mean urinary cadmium (CdU) was 1.1 micro g/g creatinine (n = 191). Higher CdU levels were associated with higher NAG.

CONCLUSIONS

These data suggest that lead has an adverse effect on renal function in the moderate dose range, particularly in older workers. Associations between higher lead measures and lower BUN and serum creatinine and higher creatinine clearances may represent lead induced hyperfiltration. Environmental cadmium may also have an adverse renal impact, at least on NAG.

Lead induced increase of blood pressure in female lead workers

AIMS

Although lead exposure has, in the absence of mathematical modelling, been believed to elevate blood pressure in females, it is necessary to clarify the relation between lead and blood pressure by eliminating confounding factors in the analysis.

METHODS

Blood lead was measured in 193 female workers, including 123 lead exposed workers. Possible confounding factors were controlled by multiple regression analyses.

RESULTS AND CONCLUSIONS

Blood lead above 40 micro g/dl was found to be the most potent factor for elevating systolic/diastolic blood pressure. Aging, urine protein, and plasma triglyceride also contributed to systolic/diastolic/pulse pressure increase, but hypertensive heredity did not. Data suggested that lead induced changes in lipoprotein metabolism may play an important role in the lead induced blood pressure increase in female workers.

Association between bone lead concentration and blood pressure among young adults

BACKGROUND

Occupational and environmental exposure to lead has been examined for its effect on blood pressure (BP) in adults with varying results. The present analyses assessed the association between bone lead concentration and BP in early adult life in persons exposed during childhood.

METHODS

Study participants included young adult members of two cohorts with different past histories of lead exposure. Lead exposure was assessed using noninvasive K-X-ray fluorescence spectroscopy to quantify bone lead concentration, an index of long-term lead exposure superior to current blood lead concentration. Systolic and diastolic BP measurements were obtained using conventional clinical methods. Multiple linear regression models were constructed to allow for control of covariates of BP identified a priori.

RESULTS

Analyses were performed on 508 participants. While controlling for potential confounders, systolic BP was 4.3 mm Hg greater among members of the highest of four bone lead concentration groups (> 10 microg Pb/g bone) when compared with the lowest bone lead concentration group (< 1 microg Pb/g bone; P = 0.004), and diastolic BP was 2.8 mm Hg greater among members of the highest bone lead concentration group when compared with the lowest bone lead concentration group (P = 0.03).

CONCLUSIONS

These results suggest that substantial lead exposure during childhood can increase BP during young adulthood.

Effect of chronic lead exposure on kidney function in male and female rats: determination of a lead exposure biomarker

Several cytotoxic chemical pollutants inducing peroxidative damages are liable to induce kidney failure. Among these pollutants we find heavy metals such as: lead, nickel, cadmium, vanadium and mercury. Lead is one of the most dangerous metals because it is widely spread in the environment, and because it may be a source of several nervous diseases. The aim of this study is to provide evidence concerning the effect of this metal on the renal function and to try to determine a storage corner in the organism which serves as an indicator of a lead intoxication. Lead acetate was administered by oral route in the drinking water to adult rats aged three months at the rate of 0.3% (P1) and 0.6% (P2). Reference rats received distilled water to drink under the same conditions. The treatment continued for 15, 30, 45, 60 and 90 days. The creatinemia, uremia, glycemia and creatinuria are determined by colorimetric techniques. Lead concentration in blood as well as the lead content of the tail are determined by atomic absorption after nitroperchloric mineralization at the liquid stage. The results showed an increase of creatinemia on the 30th day of the experiment for both sexes in (P1 and P2). The same happened for ureamia. The increase of these two parameters would indicate a renal deficiency which is confirmed by a decrease of creatinuria and urinary pH observed mainly on and after the 45th day of the experiment. An increase of the renal relative weight was noticed in P1 and P2 on the 30th day of the treatment. The determination of the concentration of lead in the blood shows that this factor increases among treated subjects in a constant way, independently of the dose and the duration of the treatment. Nevertheless, the rate increase of lead in the tail seems to be dose-dependent. In conclusion, lead administered by oral route causes a renal deficiency to the rat without distinction between males and females. In addition, the tail seems to be a reliable exposure biomarker that demonstrates lead intoxication. The tail seems to be a dosimeter of lead bio-accumulation. It constitutes an endogenous source of lead impregnation. The concentration of lead in the blood is only an indicator of recent exposure.

A pilot survey of blood lead levels in various types of workers in the United Arab Emirates

The aim of the present study is to determine the effect of blood lead on the health of industrial workers in United Arab Emirates (UAE). This is a cross-sectional pilot survey of blood lead levels (BLL) of 100 industrial workers (exposed) and 100 non-industrial workers (nonexposed), matched for age, sex and nationality selected from Al-Ain, Abu-Dhabi Emirate. Industrial workers had significantly higher mean of BLL (77.5+/-42.8 microg/dl and median 80.9 microg/dl) than non-industrial workers (19.8+/-12.3 microg/dl and median 11.0 microg/dl). In the present study, reported symptoms among industrial workers were strongly associated with BLL nausea/vomiting, muscular symptoms, dizziness, fatigue, irritability, memory disturbances, insomnia and allergic conjuctivitis, rhinitis and dermatitis. Furthermore, the present study revealed that industrial workers had higher prevalence of respiratory symptoms for phlegm, shortness of breath and diagnosed asthma. In conclusion, this study determined that occurrence of certain symptoms might be associated with lead exposure among industrial workers.

Blood pressure, left ventricular mass, and lead exposure in battery manufacturing workers

BACKGROUND

Although debate about the relationship between lead and blood pressure has focused on low environmental lead levels, industrial exposure remains a concern.

METHODS

We measured blood pressure and left ventricular mass (LVM) in 108 battery manufacturing workers, and calculated cumulative and historic average measures of blood lead.

RESULTS

Diastolic pressure increased with increasing lead levels, with a significant (P = 0.04) 5 mmHg difference in mean pressure between the highest and lowest cumulative exposure levels. Diastolic pressure increased with the log of cumulative lead (P = 0.06). Both hypertension (defined as currently medicated or systolic > 160 mmHg or diastolic > 95 mmHg) and LVM increased nonsignificantly with increasing lead exposure (P-values > or = 0.17 for hypertension and > or = 0.20 for LVM).

CONCLUSIONS

We found a small effect of blood lead on diastolic blood pressure, particularly for a cumulative measure of exposure, but no convincing evidence of associations between lead and other blood-pressure-related outcomes. Published 2001 Wiley-Liss, Inc.