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

Association between blood metal exposures and hyperuricemia in the U.S. general adult: A subgroup analysis from NHANES

BACKGROUND

The relationship between metal exposure and hyperuricemia is still controversial, especially in certain population groups.

METHODS

This cross-sectional study included adults from NHANES 2011-2016. Seven metals, including Pb, Cd, Hg, Mn, Se, Cu, and Zn, were detected in blood by ICP‒MS. Multivariable logistic regression, LASSO, and BKMR models were used to assess the effects of single and mixed metal exposures and hyperuricemia. Moreover, this association was analyzed by sex, BMI, and age.

RESULTS

A total of 4074 individuals were included in our final analysis, and 825 (20.3%) people were classified as having hyperuricemia. In logistic regression, Pb (Q4: OR [95% CI]: 1.50 [1.00, 2.24]) was associated with hyperuricemia after adjusting for all covariates. LASSO penalized regression analysis further indicated positive associations of lead and zinc with hyperuricemia. In BKMR analysis, U-shaped dose‒response curves were generated for Se, Mn, Cu, and Zn when fixing the other metals in the 50th percentile. A significant positive trend was found between mixed metal exposure and hyperuricemia, in which blood Se, Zn, and Cd had the highest PIP (PIP = 0.651, 0.549, and 0.530, respectively). In weighted logistic regression, subgroup analyses revealed a significant association between Pb and hyperuricemia among the non-overweight group. Significant positive trends between mixed metals and hyperuricemia were found in the male and non-overweight groups in the BKMR models.

CONCLUSION

Our study suggests that a higher concentration of mixed metal might increase the risk of hyperuricemia in U.S. adults. Males and people with a BMI under 25 are more likely to be affected.

High-density lipoprotein cholesterol modifies the association between blood lead and uric acid: results from NHANES 2005-2016

BACKGROUND

The association between blood lead (PbB) and uric acid (SUA) remains unclear in US adults without a high level of lead exposure. Additionally, the effects of high-density lipoprotein cholesterol (HDL-C) modifying this association are still unclear. Therefore, this study aims to assess the effect of modification of high-density lipoprotein cholesterol on the association between PbB and SUA.

METHOD

This research analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2016. Through several screenings, 18,578 participants over the age of 20 were eligible for the analysis. Multivariable linear regression was used to evaluate the association between PbB and SUA. By having stratified participants based on the HDL-C intake category (low HDL-C intake < 50 mg/dl; high HDL-C intake ≥ 50 mg/dl), effect modification by HDL-C was assessed through a likelihood ratio test between PbB and SUA.

RESULT

Multivariable linear regression indicated that PbB positively affects SUA (β = 0.19, 95% CI 0.16-0.22). The relationship between PbB and SUA was different in the low and high HDL-C intake group (β 0.12 95% Cl 0.08-0.16 vs. β 0.26 95% Cl 0.22 ~ - 0.30). Furthermore, high-density lipoprotein cholesterol significantly modified the relationship between PbB and SUA in all models which indicates that the interaction of lead exposure and HDL-C is more dangerous than the sum of the individual effects.

CONCLUSIONS

Our study shows that high-density lipoprotein cholesterol and blood lead have an interactive effect on increasing uric acid, which may have great importance for clinical medication.

Prenatal lead exposure, telomere length in cord blood, and DNA methylation age in the PROGRESS prenatal cohort

BACKGROUND

Lead is a ubiquitous pollutant with deleterious effects on human health and remains a major current public health concern in developing countries. This heavy metal may interfere with nucleic acids via oxidative stress or epigenetic changes that affect biological markers of aging, e.g., telomere length and DNA methylation (DNAm). Telomere shortening associates with biological age in newborns, and DNA methylation at specific CpG sites can be used to calculate "epigenetic clocks".

OBJECTIVE

The aim of this study was to examine the associations of prenatal lead exposures with telomere length and DNA-methylation-based predictors of age in cord blood.

DESIGN

The study included 507 mother-child pairs from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) study, a birth cohort in Mexico City. Maternal blood (second trimester, third trimester and at delivery) and bone lead levels (one month postpartum) were measured using inductively coupled plasma-mass spectrometry and X-ray fluorescence, respectively. Cord blood leukocyte telomere length was measured using quantitative PCR and apparent age by DNA methylation biomarkers, i.e., Horvath's DNA methylation age and the Knight's predictor of gestational age.

RESULTS

Average maternal age was 28.5 ± 5.5 years, and 51.5% reported low socioeconomic status. Children's mean telomere length was 1.2 ± 1.3 relative units, and mean DNA methylation ages using the Horvath's and Knight's clocks were -2.6 ± 0.1 years and 37.9 ± 1.4 weeks (mean ± SD), respectively. No significant associations were found between maternal blood and bone lead concentrations with telomere length and DNAm age in newborns.

CONCLUSION

We found no associations of prenatal lead exposure with telomere length and DNA methylation age biomarkers.

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.

Assessment of potters' occupational exposure to lead and associated risk factors in Maragogipinho, Brazil: preliminary results

BACKGROUND AND PURPOSE

Lead (Pb) is used as a flux in the glazing process of pottery utensils in several regions of the world. It can affect the nervous and hematopoietic systems; in addition, it is classified as a probable human carcinogen. This work aims to evaluate Pb exposure of potters and describe the main determinants of elevated blood Pb (PbB) levels in this group of workers.

METHODS

This is a cross-sectional study with potters of Maragogipinho Village, Bahia, Brazil, of both sexes, aged 16-72 years (n = 85). Non-exposed workers of the same age range residing in the urban area of Aratuípe town were also recruited (n = 50). We evaluated Pb dust deposition rates (PbDrt) in pottery workshops and PbB levels. All Pb measurements were performed by Graphite Furnace Atomic Absorption Spectrometry.

RESULTS

The median of PbB (min-max) and geometric mean (SD) PbDrt for the exposed group were 7.9 (0.9-49.8) µg/dL and 1463 (± 290,000) μg/m²/30 days, respectively. For the control group, levels were 1.5 (0.1-19.8) μg/dL and 82 (46) μg/m² 30 days, respectively.

CONCLUSION

The data found showed an excessive exposure among artisans, exceeding occupationally safe levels and those reported in the literature. It is important to implement occupational hygiene measures and improvements of the working conditions of these labors, especially the replacement of lead oxide in the pottery-glazing process.

Associations of plasma metal concentrations with the decline in kidney function: A longitudinal study of Chinese adults

Metals are widespread pollutants in the environment which have been reported to be associated with kidney dysfunction in many existing epidemiological studies. However, most of the studies are cross-sectional design and mainly focus on several toxic metals including arsenic, lead and cadmium. Therefore, we conducted this prospective study within the Dongfeng-Tongji cohort to evaluate the associations of plasma multiple metals with the decline in kidney function among Chinese middle-aged and elderly. In total, 1434 participants free of chronic diseases at baseline were included in analysis. We measured baseline plasma concentrations of 23 metals and calculated estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation based on serum creatinine, age, sex and ethnicity. Bonferroni correction was used for multiple testing to reduce the probability of a type I error. Principal component analysis was conducted to evaluate the combined effect of multiple metal co-exposure. Most of the plasma metal concentrations were within the literature reported reference values, whereas the concentration of lead and nickel exceeded the guideline value. We found that plasma concentrations of aluminum, arsenic, barium, lead, molybdenum, rubidium, strontium, vanadium and zinc were significantly associated with the decline in kidney function measured by annual eGFR decline, rapid renal function decline (defined as an annual decline in eGFR ≥ 5 mL/min/1.73 m²) or incident eGFR < 60 mL/min/1.73 m², with the adjusted beta coefficients (95% CI) for annual eGFR decline 0.50 (0.30, 0.69), 0.98 (0.74, 1.23), 0.56 (0.32, 0.79), 0.21 (0.03, 0.39), 0.35 (0.16, 0.54), 0.94 (0.71, 1.17), 0.37 (0.15, 0.60), 0.78 (0.54, 1.02), and 0.74 (0.57, 0.91), respectively. The metals exposures were linked with increased risks of impaired kidney function. Associations of principal components representing these metals with the decline in kidney function were significant and suggest a possible additional health risk by co-exposure. Participants engaged in manufacturing had higher plasma levels of several metals compared with those who had been involved in management- or administration-related work. Our findings suggest that exposure to multiple metals contribute to the decline in kidney function among the middle-aged and elderly. Co-exposure to multiple metals may have synergetic effect on the kidney function. Further studies are warranted to confirm our findings and clarify the potential mechanisms.

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.

Association of urinary metal profiles with serum uric acid: a cross-sectional study of traffic policemen in Wuhan, China

OBJECTIVES

Serum uric acid (SUA) is both a strong antioxidant and one of the key risk factors of cardiovascular diseases (CVDs). We aimed to investigate the associations of urinary metal profile with SUA in traffic policemen in Wuhan, China.

DESIGN

A cross-sectional study was carried out in traffic policemen.

SETTING

A seriously polluted Chinese city.

PARTICIPANTS

A total of 186 traffic policemen were recruited in this study. About 56 of them worked in the logistics department and the other 130 maintained traffic order or dealt with traffic accidents on the roads. All these subjects had worked as a policeman for at least 1 year.

MAIN OUTCOME MEASURES

SUA.

RESULTS

The significantly negative association of lead with SUA was consistent between single-metal and multiple-metal models (p=0.004 and p=0.020, respectively). Vanadium, chromium and tin were reversely associated with SUA levels in the single-metal models after false discovery rate (FDR) adjustment (all P_{_FDR} < 0.05). One IQR increase in vanadium, chromium, tin and lead was associated with 26.9 µmol/L (95% CI -44.6 to -9.2; p=0.003), 27.4 µmol/L (95% CI -46.1 to -8.8; p=0.004), 11.2 µmol/L (95% CI -18.9 to -3.4; p=0.005) and 16.4 µmol/L (95% CI -27.6 to -5.2; p=0.004) decrease in SUA, respectively. Significant interaction between smoking and vanadium on decreased SUV was found (p_{for interaction} = 0.007 and p_{_FDR} = 0.028).

CONCLUSIONS

Urinary vanadium, chromium, tin and lead were negatively associated with SUA. Vanadium and cigarette smoking jointly affected SUA levels. Further studies are needed to replicate these findings and to investigate the potential mechanisms.

Chronic Kidney Disease and Exposure to Nephrotoxic Metals

Chronic kidney disease (CKD) is a common progressive disease that is typically characterized by the permanent loss of functional nephrons. As injured nephrons become sclerotic and die, the remaining healthy nephrons undergo numerous structural, molecular, and functional changes in an attempt to compensate for the loss of diseased nephrons. These compensatory changes enable the kidney to maintain fluid and solute homeostasis until approximately 75% of nephrons are lost. As CKD continues to progress, glomerular filtration rate decreases, and remaining nephrons are unable to effectively eliminate metabolic wastes and environmental toxicants from the body. This inability may enhance mortality and/or morbidity of an individual. Environmental toxicants of particular concern are arsenic, cadmium, lead, and mercury. Since these metals are present throughout the environment and exposure to one or more of these metals is unavoidable, it is important that the way in which these metals are handled by target organs in normal and disease states is understood completely.

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence

OBJECTIVES

Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach.

METHODS

We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period.

RESULTS AND DISCUSSION

We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

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.

Urinary and blood cadmium and lead and kidney function: NHANES 2007-2012

BACKGROUND

Cadmium (Cd) and lead (Pb) are widespread environmental contaminants that are known nephrotoxins. However, their nephrotoxic effects at low-environmental exposure levels are debated.

OBJECTIVE

We examined the association of blood Pb (B-Pb), blood Cd (B-Cd), urinary Pb (U-Pb) and urinary Cd (U-Cd) with estimated glomerular filtration rate (eGFR) and urinary albumin (ALB).

METHODS

We used multivariate linear regression to analyze the association between B-Pb, B-Cd, U-Pb, and U-Cd with eGFR and ALB in adult participants (≥20 years of age) in NHANES 2007-2012. The dataset was limited to NHANES individuals with both blood and urinary metal measurements.

RESULTS

We found a statistically significant inverse association between eGFR and B-Cd and statistically significant positive associations between eGFR and both U-Cd and U-Pb, as well as statistically significant associations between ALB and the 3rd and 4th quartiles of U-Cd.

CONCLUSIONS

The inverse association between eGFR and B-Cd, in conjunction with positive associations between eGFR and ALB with U-Cd, suggest that U-Cd measurement at low levels of exposure may result from changes in renal excretion of Cd due to kidney function and protein excretion. However, renal effects such as hyperfiltration from Cd-mediated kidney damage or creatinine-specific Cd effects cannot be excluded with this cross-sectional design.

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.

Identification of environmental sources of lead exposure in Nunavut (Canada) using stable isotope analyses

BACKGROUND

Blood lead levels (BLLs) were measured in the adult Inuit population of Nunavut, Northern Canada, during the Inuit Health Survey (IHS) in 2007-2008. Approximately 10% of the adult participants had BLL over the Health Canada's guidance of 100μg/L.

OBJECTIVES

1) To repeat the measurement of BLL among the IHS participants with high BLL and household members including pregnant women and children under 10years of age; 2) to measure lead (Pb) concentrations in environmental samples to identify potential sources and 3) to explore how Pb from environmental samples contributes to BLL using Pb stable isotopic analyses.

METHODS

Blood samples were collected from 100 adults and 56 children in 2012. A total of 169 environmental samples (tap water, house dust, paint, country food, soil, and ammunition) were collected from 14 houses from three communities where the IHS participants had the highest BLL. Total Pb concentrations and Pb isotope mass balance were determined by inductively coupled plasma-mass spectrometry (ICP-MS).

RESULTS

The geometric mean of BLL was 43.1μg/L; BLL increased with age and was higher in adults than children (71.1 vs. 17.5μg/L). Median Pb concentrations in water (1.9μg/L) and dust (27.1μg/m(2) for wiped dust, 32.6mg/kg for vacuum dust coarse fraction, and 141.9mg/kg for vacuum dust fine fraction) were generally higher than in other parts of Canada. Median Pb concentrations of food and soil coarse and fine fractions were low (36.6μg/kg, 5.4mg/kg and 11.8mg/kg respectively); paint chips exceeded the Canadian guidelines in two houses (median: 3.8mg/kg). Discriminant analyses and isotope ratio analyses showed that ammunition and house dust are major sources of Pb in this study population.

CONCLUSION

Analyses of Pb stable isotopes are useful to identify the routes of exposure to Pb. This approach can contribute to develop targeted public health programmes to prevent Pb exposure.

Effect of occupational lead exposure on α- and γ-tocopherol concentration in plasma

OBJECTIVES

Changes in enzymatic antioxidant activity are frequently observed in workers occupationally exposed to lead. Few studies have investigated the influence of lead on the non-enzymatic antioxidant system. The aim of our study was to assess the influence of occupational exposure to lead on the plasma concentration of two hydrophobic forms of vitamin E: α-tocopherol and γ-tocopherol.

METHODS

A sample of 401 healthy men, aged 19-62, participated in the study. In total, 340 of these subjects were employed at the Mine and Metallurgical Plant in southern Poland. The workers who were occupationally exposed to lead were divided into quartiles (groups of 85 subjects). The lead concentrations in the blood of the subjects in the control group and in the lead exposure quartiles correspond to the following ranges: 10-72 μg/l (control group); 82-206 μg/l (Q1); 209-308 μg/l (Q2); 308-394 μg/l (Q3) and 395-644 μg/l (Q4), respectively.

RESULTS

Significant differences were observed only for the plasma concentration of γ-tocopherol, which differed between the control group and Q1 (by 24.1%, p=0.0368), between Q1 and Q3 (by -18.8%, p=0.0115) and between Q1 and Q4 (by -25.7%, p=0.0002). Multiple linear regression analysis showed that the statistically significant, predictive properties of the γ-tocopherol plasma concentration were as follows: triglycerides (β=0.440)> age (β=0.131)> whole cholesterol (β=0.117)> blood lead concentration (β=-0.108). For α-tocopherol, significant prognostic properties were triglycerides and total cholesterol (β=0.485 and β=0.399, respectively).

CONCLUSIONS

Occupational exposure to lead is strongly correlated with the concentration of γ-tocopherol but not α-tocopherol.

Health risk assessment of lead for children in tinfoil manufacturing and e-waste recycling areas of Zhejiang Province, China

Tinfoil manufacturing and electronic waste (e-waste) recycling remain rudimentary processes in Zhejing Province, China, which could account for elevated blood lead levels (BLLs) and health impacts on children. We assessed the potential health risks of lead in tinfoil manufacturing and e-waste recycling areas. 329 children in total aged 11-12 who lived in a tinfoil manufacturing area (Lanxi), an e-waste recycling area (Luqiao) and a reference area (Chun'an) were studied. Lead levels in children's blood were determined by inductively coupled plasma mass spectrometer (ICP-MS). Blood urea nitrogen (BUN), serum creatinine, serum calcium, δ-Aminolaevulinic acid (δ-ALA) and intelligence quotient (IQ) were also measured. Geometric mean of BLLs in Lanxi, Luqiao and Chun'an were 8.11 μg/dL, 6.97 μg/dL, and 2.78 μg/dL respectively, with 35.1%, 38.9% and 0% of children who had BLLs above 10 μg/dL. The BLLs in exposed areas were much higher than those in the control area. Lanxi children had higher creatinine and calcium than Chun'an children, and Luqiao children had higher δ-ALA and lower calcium than Chun'an children. No significant differences of IQ were observed between Lanxi, Luqiao and Chun'an, however a negative relationship between BLLs and IQ was shown for the study children. The results indicated that lead pollution from e-waste recycling and tinfoil processing appears to be a potential serious threat to children's health.

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.

Reports from the field: engaging learners as interpreters for developing health messages -- designing the 'Familias Sin Plomo' English as a Second Language curriculum project

California has a recently documented problem of trans-national environmental lead exposures in imported foods from Mexico but there is limited health information available in immigrant communities about this problem. This report highlights collaborative work with English as a Second Language (ESL) learners to critically review research data on lead exposures and reframe prevention messages about lead contamination of imported foods. These messages are now integrated into ESL curricula for dissemination to Spanish-speaking populations that are disproportionately affected by lead poisoning. This 'learners as interpreters' approach is a participatory method that can be applied across a wide range of public health activities. ESL learners emerged as ideal partners in developing curriculum for lead poisoning prevention for several reasons: the parents expressed strong interest in lead poisoning prevention, several have children under age 6 when lead screenings are recommended, and many have emigrated from regions in Mexico where lead hazards were identified.

Lead-induced oxidative stress adversely affects health of the occupational workers

Lead is a persistent toxic metal and associated with impairment of various body functions in occupational workers. The main objective was to determine the lead-induced oxidative stress and adverse health effects by biochemical markers in industrial workers. One hundred and forty-eight males consisting of 87 lead-exposed industrial workers and 61 controls were included. Blood lead level (BLL) was determined on a 3010B ESA lead analyzer. Blood complete counts were done on a hematology analyzer. Biochemical markers including serum uric acid, urea, creatinine, phosphate, alanine aminotransferase (ALT), and gamma glutamyltransferase (GGT) were measured on a Selectra E auto analyzer. Serum malondialdehyde (MDA) was measured spectrophotometrically and C-reactive protein (CRP) on Immulite-1000. Results revealed that lead-exposed workers had significantly high BLLs, median (range), 29.1 (9.0-61.1) microg/dL compared with controls, 8.3 (1.0-21.7) microg/dL. Oxidative stress (MDA, GGT) and inflammatory markers (high-sensitivity CRP) were significantly increased (P < or = 0.05). Blood pressure was raised, whereas hemoglobin was decreased in exposed group (P < or = 0.002). Serum urea, uric acid, phosphate, and ALT were significantly raised in lead-exposed workers (P < or = 0.001). Serum albumin, total proteins, and glomerular filtration rate (GFR) were decreased. Blood lead showed a significant positive correlation with serum GGT (r = 0.63), MDA (r = 0.71), CRP (r = 0.75), urea (r = 0.34), creatinine (r = 0.51), and uric acid (r = 0.29) (P < or = 0.01). It is concluded that lead exposure increases oxidative stress that correlates with adverse changes in hematological, renal, and hepatic function in the occupational workers. Elevated blood lead has positive correlation with oxidative stress, inflammatory and biochemical markers that might be used to detect impairment in the body function in lead exposed workers.

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.