Lead, diabetes, hypertension, and renal function: the normative aging study

Household Water Lead and Hematologic Toxic Effects in Chronic Kidney Disease

Importance

The consequences of low levels of environmental lead exposure, as found commonly in US household water, have not been established.

Objective

To examine whether commonly encountered levels of lead in household water are associated with hematologic toxicity among individuals with advanced kidney disease, a group known to have disproportionate susceptibility to environmental toxicants.

Design, Setting, and Participants

Cross-sectional analysis of household water lead concentrations and hematologic outcomes was performed among patients beginning dialysis at a Fresenius Medical Care outpatient facility between January 1, 2017, and December 20, 2021. Data analysis was performed from April 1 to August 15, 2023.

Exposure

Concentrations of lead in household water were examined in categorical proportions of the Environmental Protection Agency's allowable threshold (15 μg/L) and continuously.

Main Outcomes and Measures

Hematologic toxic effects were defined by monthly erythropoiesis-stimulating agent (ESA) dosing during the first 90 days of incident kidney failure care and examined as 3 primary outcomes: a proportion receiving maximum or higher dosing, continuously, and by a resistance index that normalized to body weight and hemoglobin concentrations. Secondarily, hemoglobin concentrations for patients with data prior to kidney failure onset were examined, overall and among those with concurrent iron deficiency, thought to increase gastrointestinal absorption of ingested lead.

Results

Among 6404 patients with incident kidney failure (male, 4182 [65%]; mean [SD] age, 57 [14] years) followed up for the first 90 days of dialysis therapy, 12% (n = 742) had measurable lead in household drinking water. A higher category of household lead contamination was associated with 15% (odds ratio [OR], 1.15 [95% CI, 1.04-1.27]) higher risk of maximum monthly ESA dosing, 4.5 (95% CI, 0.8-8.2) μg higher monthly ESA dose, and a 0.48% (95% CI, 0.002%-0.96%) higher monthly resistance index. Among patients with pre-kidney failure hemoglobin measures (n = 2648), a higher household lead categorization was associated with a 0.12 (95% CI, -0.23 to -0.002) g/dL lower hemoglobin concentration, particularly among those with concurrent iron deficiency (multiplicative interaction, P = .07), among whom hemoglobin concentrations were 0.25 (95% CI, -0.47 to -0.04) g/dL lower.

Conclusion

The findings of this study suggest that levels of lead found commonly in US drinking water may be associated with lead poisoning among susceptible individuals.

Cerqueira F, Menezes-Filho JA. A Cross-Sectional Analysis Investigating Pregnant Women's Renal Function and Its Association with Lead and Cadmium Exposures-The DSAN Birth Cohort Study in Recôncavo Baiano, Brazil

Kidney dysfunction is increasing worldwide and is exacerbated by exposure to toxic metals. Also, pregnancy poses an overload on kidney function. We investigated how blood lead (PbB) and cadmium (CdB) levels were associated with kidney function in pregnant women from Recôncavo Baiano, Brazil, during their second trimester. In this cross-sectional study, the estimated glomerular filtration rate (eGFR) was calculated from serum creatinine and whole blood metal levels were measured by graphite furnace atomic absorption spectrophotometry in 136 volunteers. Sociodemographic data were collected using semi-structured questionnaires. The medians (IQR) of PbB, CdB, and eGFR were 0.85 µg/dL (0.45-1.75), 0.55 µg/L (0.08-0.91), and 121.8 mL/min/1.73 m2 (106.0-127.9), respectively. PbB medians were significantly higher in the eGFR < 90 group at 2.00 µg/dL (0.83, 3.10). After age-adjusted logistic regression, pregnant women with elevated PbB levels had decreased eGFR (OR = 1.82; 95%-CI, 1.14-3.14). However, the participants with elevated PbB levels who reported consuming alcohol during pregnancy or had CdB in the highest tertile had higher odds of reduced eGFR (OR = 2.44; 95%-CI, 1.30-5.47) and (OR = 11.22; 95% CI, 2.53-103.51), respectively. These results suggest that low Pb exposure may affect kidney function in pregnant women and calls for further investigation into toxic metal co-exposures on kidney function during pregnancy in at-risk communities.

Synergistic impact of co-exposures to whole blood metals on chronic kidney disease in general US adults: a cross‑sectional study of the National Health and Nutrition Examination Survey 2011-2020

The impact of exposure to metals on chronic kidney disease (CKD) has only been investigated in two-way or single metal interactions in previous studies. We investigated the associations between five single metals in blood and their mixed exposure and CKD by using the machine learning approach. Relevant data were extracted from the National Health and Nutrition Examination Survey (NHANES 2011-2020), and the level of five metals in blood detected by inductively coupled plasma mass spectrometry was considered as exposures, namely, cadmium (Cd), lead (Pb), total mercury (Hg), manganese (Mn), and selenium (Se). The correlations between individual metal and metal mixtures and CKD were then evaluated by survey-multivariable logistic regression (SMLR), generalized weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR). Altogether, our study included 12,412 participants representing 572.6 million non-institutionalized US adults. Several single metals with the high quartile of exposure showed a positive association with the CKD ratio including Cd [(AOR = 1.873, 95% CI: 1.537, 2.284), Q4], Pb [(AOR = 1.559, 95% CI: 1.295, 1.880), Q4], and total Hg [(AOR = 1.169, 95% CI: 1.018, 1.343), Q2], while Mn [(AOR = 0.796, 95% CI: 0.684, 0.927), Q2] and Se [(AOR = 0.805, 95% CI: 0.664, 0.976), Q4] were negatively associated with the CKD ratio. In light of the positive fit of the WQS regression model, a significantly positive correlation was found between mixed metals and CKD (AOR = 1.373, 95% CI: 1.224, 1.539) after full covariate adjustment, and a similar finding was also detected in the BKMR model. Our study revealed that each single metal including Cd, Pb, and total Hg might have a positive association with CKD while this association was negative for both Mn and Se. The five metals might have a positive joint effect on CKD.

Public and occupational health risks related to lead exposure updated according to present-day blood lead levels

Lead is an environmental hazard that should be addressed worldwide. Over time, human lead exposure in the western world has decreased drastically to levels comparable to those among humans living in the preindustrial era, who were mainly exposed to natural sources of lead. To re-evaluate the potential health risks associated with present-day lead exposure, a two-pronged approach was applied. First, recently published population metrics describing the adverse health effects associated with lead exposure at the population level were critically assessed. Next, the key results of the Study for Promotion of Health in Recycling Lead (SPHERL; NCT02243904) were summarized and put in perspective with those of the published population metrics. To our knowledge, SPHERL is the first prospective study that accounted for interindividual variability between people with respect to their vulnerability to the toxic effects of lead exposure by assessing the participants' health status before and after occupational lead exposure. The overall conclusion of this comprehensive review is that mainstream ideas about the public and occupational health risks related to lead exposure urgently need to be updated because a large portion of the available literature became obsolete given the sharp decrease in exposure levels over the past 40 years.

Childhood lead exposure and sex-based neurobehavioral functioning in adolescence

It is well documented that childhood lead exposure is associated with long-term decreases in intelligence quotients (IQ). Lesser known is the relationship with neurobehavioral domains, especially in adolescence. This study sought to identify cross-sectional and longitudinal associations between lead exposure and adolescent executive and visual-motor functioning and examine sex-based differences. Participants were 681 children from Jintan, China who had their blood lead levels (BLLs) assessed at age 3-5 years and 12 years old and neurobehavioral functioning assessed through the University of Pennsylvania Computerized Neurocognitive Battery (PennCNB) platform http://www.med.upenn.edu/bbl at 12 years old. Mean BLLs were 6.41 mcg/dl at age 3-5 years and 3.10 mcg/dl at 12. BLLs at 3-5 years and 12 years were used as predictors for the individual neurobehavioral domains in general linear models while controlling for father and mother occupation and education, residence location, age, and adolescent IQ. Models were run separately for males and females. In adjusted models, males BLLs at 3-5 years were associated with increased time to correctly complete tasks in multiple domains including abstraction/flexibility (β = 19.90, 95% CI( 4.26, 35.54) and spatial processing (β = 96.00, 95% CI 6.18, 185.82) at 12 years. For females in adjusted models, BLLs at 3-5 years were associated with increasing time to correctly complete tasks on the episodic memory domain task (β = 34.59, 95% CI 5.33, 63.84) at 12 years. Two adolescent cross-sectional relationships remained in the adjusted models for males only, suggesting a positive association between BLLs and increasing time for correct responses on the attentional domain task (β = 15.08, 95% CI 0.65, 29.51) and decreasing time for correct responses on the episodic memory task (β = -73.49, 95% CI -138.91, -8.06) in males at 12 years. These associations remained with and without controlling for IQ. These results suggest that lead exposure is associated with overall deficits in male and female neurobehavioral functioning, though in different domains and different timing of exposure.

Estimating the burden of diseases attributable to lead exposure in the North Africa and Middle East region, 1990-2019: a systematic analysis for the Global Burden of Disease study 2019

BACKGROUND

Lead exposure (LE) and its attributable deaths and disability-adjusted life years (DALYs) have declined in the recent decade; however, it remains one of the leading public health concerns, particularly in regions with low socio-demographic index (SDI) such as the North Africa and Middle East (NAME) region. Hence, we aimed to describe the attributable burden of the LE in this region.

METHODS

Data on deaths, DALYs, years of life lost (YLLs), and years lived with disability (YLDs) attributable to LE in the NAME region and its 21 countries from 1990 to 2019 were extracted from the Global Burden of Disease (GBD) 2019 study.

RESULTS

In 2019, the age-standardized death and DALY rates attributable to LE were 23.4 (95% uncertainty interval: 15.1 to 33.3) and 489.3 (320.5 to 669.6) per 100,000 in the region, respectively, both of which were higher among men than women. The overall age-standardized death and DALY rates showed 27.7% and 36.8% decreases, respectively, between 1990 and 2019. In this period, Bahrain, the United Arab Emirates, and Turkey had the highest decreases in the age-standardized death and DALY rates, while Afghanistan, Egypt, and Yemen had the lowest ones. Countries within high SDI quintile had lower attributable burden to LE compared with the low SDI quintile. Cardiovascular diseases and chronic kidney diseases accounted for the 414.2 (258.6 to 580.6) and 28.7 (17.7 to 41.7) LE attributable DALYs per 100,000 in 2019, respectively. The attributable YLDs was 46.4 (20.7 to 82.1) per 100,000 in 2019, which shows a 25.7% reduction (-30.8 to -22.5%) over 1990-2019.

CONCLUSIONS

The overall LE and its attributed burden by cause have decreased in the region from 1990-2019. Nevertheless, the application of cost-effective and long-term programs for decreasing LE and its consequences in NAME is needed.

Associations of multiple plasma metals with chronic kidney disease in patients with diabetes

As common contaminants, metals are non-negligible risk factors for diabetes and chronic kidney disease. However, whether there is an association between multiple metals exposure and incident chronic kidney disease (CKD) risk in patients with diabetes is unclear. We conducted a prospective study to evaluate these associations. In total, 3071 diabetics with baseline estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m² from the Dongfeng-Tongji cohort were included. We measured baseline plasma concentrations of 23 metals and investigated the associations between plasma metal concentrations and CKD in diabetics using logistic regression, the least absolute shrinkage and selection operator (LASSO), and the Bayesian Kernel Machine Regression (BKMR) models. During average 4.6 years of follow-up, 457 diabetics developed CKD (14.9 %). The three models consistently found plasma levels of zinc, arsenic, and rubidium had a positive association with incident CKD risk in patients with diabetes, while titanium, cadmium, and lead had an inverse correlation. The results of BKMR showed a significant and positive overall effect of 23 metals on the risk of CKD, when all of the metals were above the 50th percentile as compared to the median value. In addition, potential interactions of zinc and arsenic, zinc and cadmium, zinc and lead, titanium and arsenic, and cadmium and lead on CKD risk were observed. In summary, we found significant associations of plasma titanium, zinc, arsenic, rubidium, cadmium, and lead with CKD in diabetes and interactions between these metals except for rubidium. Co-exposure to multiple metals was associated with increased CKD risk in diabetics.

Use of Generalized Weighted Quantile Sum Regressions of Tumor Necrosis Factor Alpha and Kidney Function to Explore Joint Effects of Multiple Metals in Blood

Exposure to heavy metals could lead to adverse health effects by oxidative reactions or inflammation. Some essential elements are known as reactors of anti-inflammatory enzymes or coenzymes. The relationship between tumor necrosis factor alpha (TNF-α) and heavy metal exposures was reported. However, the interaction between toxic metals and essential elements in the inflammatory response remains unclear. This study aimed to explore the association between arsenic (As), cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn) in blood and TNF-α as well as kidney function. We enrolled 421 workers and measured the levels of these seven metals/metalloids and TNF-α in blood; kidney function was calculated by CKD-EPI equation. We applied weighted quantile sum (WQS) regression and group WQS regression to assess the effects of metal/metalloid mixtures to TNF-α and kidney function. We also approached the relationship between metals/metalloids and TNF-α by generalized additive models (GAM). The relationship of the exposure−response curve between Pb level and TNF-α in serum was found significantly non-linear after adjusting covariates (p < 0.001). Within the multiple-metal model, Pb, As, and Zn were associated with increased TNF-α levels with effects dedicated to the mixture of 50%, 31%, and 15%, respectively. Grouped WQS revealed that the essential metal group showed a significantly negative association with TNF-α and kidney function. The toxic metal group found significantly positive associations with TNF-α, serum creatinine, and WBC but not for eGFR. These results suggested Pb, As, Zn, Se, and mixtures may act on TNF-α even through interactive mechanisms. Our findings offer insights into what primary components of metal mixtures affect inflammation and kidney function during co-exposure to metals; however, the mechanisms still need further research.

Susceptibility to Environmental Heavy Metal Toxicity among Americans with Kidney Disease

Background

The consequences of low levels of environmental heavy metal exposure, as found widely in the United States, in those with impaired renal function remain underexplored.

Methods

We examined the cross-sectional association of indices of renal function with lead and cadmium levels in blood and urine among National Health and Nutrition Examination Survey (NHANES) participants. We used the 1999-2002 cycle, which included measures of cystatin C, in order to quantify renal function most precisely and defined chronic kidney disease (CKD) as an estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m².

Results

In weighted and adjusted analyses of 5638 participants, lead levels were 0.23 (95% CI, 0.03 to 0.42) μg/dl higher among participants with CKD, and 0.05 (95% CI, 0.01 to 0.09) μg/dL higher per 10 ml/min per 1.73 m² lower eGFR. Cadmium levels were 0.02 (95% CI, 0.01 to 0.03) μg/L higher per 10 ml/min per 1.73 m² lower eGFR. Black race significantly modified the association of lower eGFR with higher circulating lead levels (P interaction <0.001). A 10 ml/min per 1.73 m² lower eGFR was associated with a 0.13 (95% CI, 0.06 to 0.21) μg/dl higher lead level among Black participants compared with 0.03 (95% CI, -0.04 to 0.11) μg/dl higher level among White participants. Among the 1852 participants with urinary metal measurements, despite higher circulating levels, those with CKD had significantly lower urinary lead levels (-0.16 [95% CI, -0.30 to -0.01] ng/ml) and urinary lead/creatinine ratios (-0.003 [95% CI, -0.004 to -0.001]).

Conclusions

CKD is associated with higher blood lead levels, particularly among Blacks, and simultaneously, lower urinary lead levels, consistent with the hypothesis that CKD confers a state of heighted susceptibility to heavy metal environmental exposure by reducing its elimination. Given that low levels of exposure remain highly prevalent in the United States, further efforts to protect patients with CKD from heavy metal toxicity may be warranted.

Biochemical and hematological effects of lead exposure in Iranian battery workers

OBJECTIVE

The purpose of our study was to evaluate the hematotoxic, hepatotoxic, and nephrotoxic responses following lead exposure among battery workers.

MATERIAL AND METHODS

Seventy-eight battery workers exposed to lead, and 78 non-exposed subjects were studied. Fasting blood samples were collected to assess kidney and liver function and hematological parameters. To determine the breathing zone and blood lead levels (BLLs), the samples were analyzed in accordance with the 7082 and 8003 NIOSH methods, respectively.

RESULTS

The battery workers had significantly higher breathing zone lead and BLLs than the non-exposed group. In battery workers, the most hematological parameters, including red blood cell, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, have significantly decreased. In contrast, white blood cell count has shown a significant increase as compared to the controls. The mean levels of alanine aminotransferase, aspartate aminotransferase as biomarker liver damage, and the serum levels of creatinine as a result of renal failure were significantly higher in the exposed group than in the non-exposed group.

CONCLUSIONS

These observations indicate that occupational exposure to lead exceeding its current threshold limit value (TLV) and biological exposure index (BEI) is associated with hematological symptoms and liver and kidney dysfunction.

Two-year responses of renal function to first occupational lead exposure

Introduction

Whether in advanced countries lead exposure still contributes to renal impairment is debated, because blood lead (BL) level is declining toward preindustrial levels and because longitudinal studies correlating renal function and BL changes over time are scarce.

Methods

The Study for Promotion of Health in Recycling Lead (SPHERL) evaluated the 2-year renal function responses in 251 workers (mean age, 29.7 years) transiting from environmental to occupational exposure. Main study end point was the estimated glomerular filtration rate (eGFR) derived from serum creatinine (eGFRcrt), cystatin C (eGFRcys), or both (eGFRcc). BL level was measured by inductively coupled plasma mass spectrometry (detection limit 0.5 μg/dl).

Results

In the follow-up, mean baseline BL level of 4.13 μg/dl increased 3.30-fold. In fully adjusted mixed models, additionally accounting for the within-participant clustering of the 1- and 2-year follow-up data, a 3-fold BL level increment was not significantly correlated with changes in eGFR with estimates amounting to −0.86 (95% CI: −2.39 to 0.67), −1.58 (−3.34 to 0.18), and −1.32 (−2.66 to 0.03) ml/min per 1.73 m² for eGFRcrt, eGFRcys, or eGFRcc, respectively. Baseline BL level and the cumulative lead burden did not materially modify these estimates, but baseline eGFR was a major determinant of eGFR changes showing regression to the mean during follow-up. Responses of serum osmolarity, urinary gravity, or the urinary albumin-to-creatinine ratio (ACR) were also unrelated to the BL level increment. The age-related decreases in eGFRcrt, eGFRcys, and eGFRcc were −1.41, −0.96, and −1.10 ml/min per 1.73 m², respectively.

Conclusion

In the current study, the 2-year changes in renal function were unrelated to the increase in BL level. However, given the CIs around the point estimates of the changes in eGFRcc and eGFRcys, a larger study with longer follow-up is being planned.

Relationships Between Indicators of Metabolic Disorders and Selected Concentrations of Bioelements and Lead in Serum and Bone Tissue in Aging Men

BACKGROUND

The aim of this study was to investigate the relationships between serum and bone concentrations of selected bioelements, ie, zinc (Zn), copper (Cu), iron (Fe), chrome (Cr), magnesium (Mg), and selenium (Se), and a heavy metal, ie, lead (Pb), and the selected indicators of metabolic disorders - Visceral Adiposity Index (VAI), Lipid Accumulation Product (LAP) and Body Mass Index (BMI).

MATERIAL AND METHODS

The study comprised 151 men aged 60 to 75 years who were scheduled for hip replacement surgery due to osteoarthritis. The concentrations of elements in the serum and bone tissue were measured using inductively coupled plasma optical emission spectrometry (Mg, Zn, Cu, Cr, Fe, and Pb) and the spectrofluorometric method (Se). Fasting plasma glucose (FPG), high-density cholesterol (HDL-Ch), and triacylglycerols (TAG) were determined. Lipid accumulation product (LAP) and visceral adiposity index (VAI) were calculated.

RESULTS

There was no relationship between serum and bone concentrations of bioelements and lead and the BMI index. Bone Mg was significantly higher in men with higher VAI, but no such relation was observed in the serum. Similarly, bone Mg and Zn were higher in patients with higher LAP, which was not observed in the serum. Multivariate logistic regression analysis with adjustment for age was performed. There was a correlation between serum Zn concentration and the cut-off point for VAI. The cut-off point for LAP was related to the bone tissue concentrations of Mg, Zn, and Cu.

CONCLUSION

We found some relationships between the concentrations of selected bioelements and Pb and VAI, LAP, and BMI in bone but not in the serum. VAI positively correlated with bone Mg, while LAP positively correlated with bone Cu, Zn, and Mg.

Human biomonitoring of toxic and essential metals in younger elderly, octogenarians, nonagenarians and centenarians: Analysis of the Healthy Ageing and Biomarkers Cohort Study (HABCS) in China

BACKGROUND

Metals can be either toxic or essential to health, as they play different role in oxidative stress and metabolic homeostasis during the ageing process. Population-based biomonitoring have documented levels and ranges in concentrations among general population of 0-79 years of age. In people aged 80 and above, toxic metals and essential metals may have different risk profiles, and thus need to be better studied.

OBJECTIVE

Our aim is to investigate concentrations of toxic metals (arsenic, cadmium, lead and mercury) and essential metals (chromium, cobalt, molybdenum, manganese, nickel and selenium) and their role in diseases, nutritional status among younger elderly, octogenarians, nonagenarians and centenarians.

METHODS

A total of 932 younger elderly, 643 octogenarians, 540 nonagenarians, 386 centenarians were included from the cross-sectional Healthy Aging and Biomarkers Cohort Study in 2017-2018. Blood or urine biological substrates were collected from each participant to determine the concentrations of toxic metals and essential metals by inductively coupled plasma mass spectrometry. Random forest was constructed to rank the importance of toxic metals and essential metals in longevity. LASSO penalized regressions were performed to select the most significant metals associated with diseases and nutritional status, of which simultaneously included all metals and adjusted for the confounding factors.

RESULTS

Compared to women, we found higher biomarker concentrations in men for toxic metals (41.2 µg/L vs 34.4 µg/L for blood lead, 1.56 µg/L vs 1.19 µg/L for blood mercury) and lower concentration of essential metals (0.48 µg/L vs 0.58 µg/L for blood molybdenum, 10.0 µg/L vs 11.1 µg/L for blood manganese). These factors may contribute to gender difference observed in longevity, that women live longer than men. Blood lead and urine cadmium tended to increase with age (P <0.001); blood cobalt, molybdenum, manganese increased with age, blood selenium decreased with age while the prevalence of selenium deficiency was extremely low in centenarians. Among toxic metals and essential metals, LASSO penalized regression identified the most significant metals associated with chronic kidney disease was cadmium and arsenic; and it was manganese, cobalt, and selenium for diabetes; it was selenium, molybdenum, lead for anemia; it was mercury for underweight. In random forest model, the top four important metals in longevity were selenium, arsenic, lead and manganese both in men and women.

CONCLUSIONS

Generally, toxic metals levels were significantly higher while essential metals were relatively sufficient in Chinese centenarians. Toxic metals and essential metals played different role in diseases, nutritional status and longevity in the process of aging. Our research provided real world evidence of biomonitoring reference values to be used for the ongoing population health surveillance in longevity.

Blood lead, nutrient intake, and renal function among type 2 diabetic patients

Lead (Pb) exposure has been reported to have nephrotoxicity. However, such an effect has not been well investigated in type 2 diabetes (T2D) patients, especially when taking into account the nutrition status of the patients. Therefore, we explore the association between blood lead levels (BLLs), dietary intake of nutrients, and impaired renal function among patients with T2D. We measured BLLs and biochemical parameters of renal injury in 780 patients. Dietary nutrients intake was assessed by a food frequency questionnaire in 420 of 780 participants. We found high BLLs were significantly associated with certain parameters of renal injury, and dietary intake of specific nutrients (mainly micronutrients) was associated with reduced BLLs at high percentile distribution of concentration. BLLs were also found to have moderation effects on the association between specific dietary nutrients and specific renal function parameters.

The Aging Kidney-As Influenced by Heavy Metal Exposure and Selenium Supplementation

The aging process in the kidneys has been well studied. It is known that the glomerular filtration rate (GFR) declines with age in subjects older than 50–60 years. However, there is still insufficient knowledge regarding the response of the aged kidney to environmental toxicants such as mercury, cadmium, and lead. Here, we present a review on the functional decline and proposed mechanisms in the aging kidney as influenced by metal pollutants. Due to the prevalence of these toxicants in the environment, human exposure is nearly unavoidable. Further, it is well known that acute and chronic exposures to toxic metals may be detrimental to kidneys of normal adults, thus it may be hypothesized that exposure of individuals with reduced GFR will result in additional reductions in renal function. Individuals with compromised renal function, either from aging or from a combination of aging and disease, may be particularly susceptible to environmental toxicants. The available data appear to show an association between exposure to mercury, cadmium and/or lead and an increase in incidence and severity of renal disease in elderly individuals. Furthermore, some physiological thiols, as well as adequate selenium status, appear to exert a protective action. Further studies providing improved insight into the mechanisms by which nephrotoxic metals are handled by aging kidneys, as well as possibilities of therapeutic protection, are of utmost importance.

Blood lead, vitamin D status, and albuminuria in patients with type 2 diabetes

Environmental lead exposure has been linked with reduced kidney function. However, evidence about its role in diabetic kidney damage, especially when considering the nutritional status of vitamin D, is sparse. In this observational study, we investigated the association between low-level lead exposure and urinary albumin-to-creatinine ratio (UACR) and assessed potential impact of vitamin D among 4033 diabetic patients in Shanghai, China. Whole blood lead was measured by graphite furnace atomic absorption spectrometry. Serum 25-hydroxyvitamin D [25(OH)D] was tested using a chemiluminescence immunoassay. The associations of blood lead with UACR and albuminuria, defined as UACR ≥30 mg/g, according to 25(OH)D levels were analyzed using linear and Poisson regression models. A doubling of blood lead level was associated with a 10.7% higher UACR (95% CI, 6.19%-15.5%) in diabetic patients with 25(OH)D < 50 nmol/L, whereas the association was attenuated toward null (2.03%; 95% CI, -5.18% to 9.78%) in those with 25(OH)D ≥ 50 nmol/L. Similarly, the risk ratios of prevalent albuminuria per doubling of blood lead level between the two groups were 1.09 (95% CI, 1.03-1.15) and 0.99 (95% CI, 0.86-1.14), respectively. Joint analysis demonstrated that a combination of high blood lead and low 25(OH)D corresponded to significantly higher UACR. Among diabetic patients with 25(OH)D < 50 nmol/L, the increment of UACR relative to blood lead was more remarkable in those with reduced estimated glomerular filtration rate (<60 mL/min/1.73 m²). These results suggested that higher blood lead levels were associated with increased urinary albumin excretion in diabetic patients with vitamin D deficiency. Further prospective studies are needed to validate our findings and to determine whether vitamin D supplementation yields a benefit.

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.

Incorporating pharmacokinetic data into personalised prescribing for older people: challenges and opportunities

PURPOSE

We discuss the known age-associated changes in drug metabolism and elimination, the potential use of this information when selecting specific therapeutic strategies in older patients, and the steps required to fill the knowledge gap in this field.

METHODS

We conducted a narrative review that encapsulates the current knowledge regarding the main age-associated changes in drug metabolism and elimination and discusses their possible inclusion in current and future personalised prescribing tools for the older patient population.

RESULTS

Despite some progress in this field, the lack of specific information regarding the impact of frailty, pharmacogenomics, and drug-drug, drug-disease, and organ-organ interactions, particularly in subjects > 80 years, currently prevents the routine incorporation of pharmacokinetic data, barring measures of renal function, into personalised prescribing tools.

CONCLUSIONS

The incorporation of pharmacokinetic data into personalised prescribing, an approach based on the consideration of a number of patient's characteristics when selecting the right drug(s) and dose regimen(s) to maximize effectiveness and limit toxicity, remains a hypothetical construct in geriatric care. Pending the inclusion of frail and complex older patients in pre- and post-marketing studies, a better understanding of the key pharmacokinetic alterations of common medications in "real-life" patients, together with the implementation of effective strategies tackling inappropriate prescribing, is likely to improve clinical outcomes and reduce healthcare utilization in the older population.

Associations of Blood Heavy Metals with Uric Acid in the Korean General Population: Analysis of Data from the 2016-2017 Korean National Health and Nutrition Examination Survey

We hypothesized that blood heavy metal levels such as lead, cadmium, and mercury were associated with uric acid level and hyperuricemia, and that this association remains significant after adjustment for other metals. We tested this hypothesis using the Korean National Health and Nutrition Examination Survey data. Beta coefficients and 95% confidence intervals (95% CIs) were calculated using multiple linear regression, and odds ratios (ORs) and 95% CIs were calculated using logistic regression in the cross-sectional study design. Relative to women, men had a higher geometric mean (GM) of lead (1.95 vs. 1.50 μg/dL) and mercury (3.94 vs. 2.77 μg/L), a lower GM of cadmium (0.80 vs. 1.04 μg/L), and a higher arithmetic mean (AM) of uric acid (5.84 vs. 4.40 mg/dL). Women had significant positive associations of log uric acid level with doubling of lead and mercury, and negative association with cadmium. Logistic regression analysis indicated the inverse association of serum hyperuricemia with doubling of blood metals was only significant for cadmium in women (OR = 0.641, 95% CI = 0.463 to 0.886) and the associations of serum hyperuricemia in the highest versus lowest quartiles of heavy metals were only significant for cadmium in women (OR = 0.495, 95% CI = 0.246 to 0.998). For both genders, age and estimated glomerular filtration rate (e-GFR) had negative associations with uric acid, but hypertension and triglycerides had positive associations with uric acid. In conclusion, blood lead and mercury levels were positively associated with uric acid level, but blood cadmium level was inversely associated with uric acid level and hyperuricemia in women.

Lead exposure and its association with cardiovascular disease and diabetic kidney disease in middle-aged and elderly diabetic patients

AIMS

Previous studies have suggested that a high blood lead level (BLL) is associated with cardiovascular outcomes and impaired renal function in the general population; however, studies investigating the effect of a high BLL on diabetic vascular complications have been limited. We aimed to investigate whether a higher BLL is associated with cardiovascular disease (CVD) and diabetic kidney disease (DKD).

METHODS

We analyzed 4234 individuals out of 4813 diabetic participants enrolled from seven communities in China in 2018 in this cross-sectional study. Macrovascular measurements, including assessment of common carotid artery (CCA) plaques and their diameters, were performed with ultrasound. CVD was defined as a composite measure including a previous diagnosis of coronary heart disease, myocardial infarction, or stroke. The definition of DKD was an albumin to creatinine ratio (ACR) ≥30 mg/g or an estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73 m². Linear and logistic regression analyses were used to measure the associations.

RESULTS

The median age and BLL of the participants were 67 years (interquartile range, 62-72 years) and 26 μg/L (interquartile range, 18-36 μg/L). Compared with the first quartile, the odds ratio (OR) (95% CI) of CCA plaques ranging from none to bilateral in the ordinal logistic regression analysis associated with BLL was 1.53 (1.29, 1.82) in the fourth BLL quartile (P for trend <0.01), and the odds of having CVD was significantly increased by 44% for participants in the fourth quartile (1.44 (1.17, 1.76)) (P for trend <0.01). The odds of DKD in the fourth BLL quartile increased by 36% (1.36 (1.06, 1.74)) compared with that in the first quartile (P for trend <0.05). These associations were adjusted for potential confounders.

CONCLUSIONS

A high BLL may be a potential risk factor for CVD and DKD in middle-aged and elderly diabetic adults.

Comparison of blood lead concentrations in patients with acute ischemic stroke and healthy subjects

BACKGROUND AND OBJECTIVES

Stroke is the main cause of mortality and long-term disability in the general population. With the increased application of metals in industries and human environment, lead has become a health hazard. In this study, we aimed to evaluate the relationship between the blood concentration of lead and the incidence of acute stroke.

MATERIALS AND METHODS

We performed this study during 2016-17 at Vali-e-Asr Hospital in Birjand, Iran, among 80 ischemic stroke patients visiting the hospital and 80 healthy gender- and age-matched controls. Blood lead concentration (BLC) was measured using graphite furnace atomic absorption spectrometry.

RESULTS

BLC medians in the case and control groups were 20.65 [5.37-34.87] μg/dL and 2.65 [1.75-13.85] μg/dL, respectively (p < 0.05). The case group had significantly lower mean levels of HDL and phosphors, whereas the mean levels of white blood cells and uric acid were higher in this group. After adjusting for lipid profile and fasting blood sugar, multiple logistic regression indicated that the serum levels of uric acid and BLC were significant for predicting ischemic stroke. It is estimated that the odds ratio of ischemic stroke increases by 1.04 per 1 μg/dl increase in BLC.

CONCLUSION

This study showed that lead can be a risk factor for ischemic stroke. Since it does not have any beneficial effects on the health of individuals, screening serum concentrations of lead can be considered as a preventive strategy for those at risk of stroke.

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.

Serum Selenium and Lead Levels: a Possible Link with Diabetes and Associated Proteinuria

The study assessed trace element selenium (Se) and a heavy metal lead (Pb) in patients with type II diabetes mellitus (T2DM) and its associated proteinuria. Total 275 subjects aged between 30 and 90 years were studied: 93 T2DM, 98 T2DM with proteinuria, and 84 as controls. Serum Se and Pb were analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES) and other biochemical indices by ROCHE module COBAS 6000 analyzer. Statistical analysis was done by one-way analysis of variance (ANOVA) at P < 0.0001 followed by Tukey's honest test. Pearson's correlation coefficient was applied to observe the effects of Se and Pb on FPG and ACR. Decreased Se levels were observed in T2DM and T2DM with proteinuria with no significant difference and serum Pb was found within reference range in both groups. Se showed no significant association with FBG and ACR while mid-upper tertile of Pb was significantly associated with ACR of T2DM with the proteinuria group (P < 0.01). Se is known to have a U-shaped relationship with T2DM. Low Se levels in both groups may be due to the effect of disease and its related inflammation. Detected levels of Pb suggest that studied population had lower exposure to it. Association of Pb with ACR showed consistency with the classical studies that even low levels of Pb may cause the renal deterioration.

Examining environmental contaminant mixtures among adults with type 2 diabetes in the Cree First Nation communities of Eeyou Istchee, Canada

Type 2 diabetes mellitus (T2DM) disproportionately affects Indigenous populations. It is possible that exposure to complex mixtures of environmental contaminants contribute to T2DM development. This study examined the association between complex environmental contaminant mixtures and T2DM among Canadian Indigenous communities from the Eeyou Istchee territory, Quebec, Canada. Using data from the cross-sectional Multi-Community Environment-and-Health Study (2005–2009) Principal Component Analysis (PCA) was used to reduce the dimensionality of the following contaminants: 9-polychlorinated biphenyl congeners; 7-organic pesticides; and 4-metal/metalloids. Following this data reduction technique, we estimated T2DM prevalence ratios (PR) and 95% confidence intervals using modified Poisson regression with robust error variance across derived principal components, adjusting for a priori covariates. For both First Nation adult males (n = 303) and females (n = 419), factor loadings showed dichlorodiphenyltrichloroethane (DDT) and lead (Pb) highly loaded on the second principal component (PC) axis: DDT negatively loaded, and Pb positively loaded. T2DM was significantly associated with PC-2 across all adjusted models. Because PCA produces orthogonal axes, increasing PC-2 scores in the fully adjusted model for females and males showed (PR = 0.84; 95% CI 0.72, 0.98) and (PR = 0.78; 95% CI 0.62, 0.98), respectively. This cross-sectional study suggests that our observed association with T2DM is the result of DDT, and less likely the result of Pb exposure. Further, detectable levels of DDT among individuals may possibly contribute to disease etiology.

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.

ICP-DRC-MS analysis of serum essential and toxic element levels in postmenopausal prediabetic women in relation to glycemic control markers

PURPOSE

Assessment of the influence of prediabetes on serum trace element and electrolyte levels in postmenopausal women.

METHODS

A total of 80 prediabetic and 80 healthy postmenopausal women took part in the present study. Serum was analyzed for glucose, insulin, insulin resistance index (HOMA-IR), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT). Glycated haemoglobin (HbA1c) levels were also assessed. Serum levels of 28 elements were estimated using inductively-coupled plasma mass spectrometry with dynamic reaction cell technology (ICP-DRC-MS).

RESULTS

Prediabetic women were characterized by significantly higher HbA1c, glucose, insulin, HOMA-IR, ALT, and GGT values. Of trace elements, only serum zinc (Zn) levels were significantly lower in prediabetics by 10% (p=0.001) when compared to the controls. Serum Zn levels were characterized by a significant inverse correlation with HbA1c (r=- 0.205; p=0.009), insulin (r=- 0.246; p=0.002), and HOMA-IR (r=- 0.227; p=0.004). Multiple regression analysis demonstrated a significant inverse association between serum Zn (β=-0.169; p=0.031) and Sr (β=-0.192; p=0.012) and HOMA-IR values after adjustment for anthropometric and biochemical parameters (p for a model <0.001). Although serum Zn was significantly associated with HbA1c both in crude and adjusted models, no significant relationship was detected after adjustment for age and anthropometric parameters.

CONCLUSIONS

Prediabetic postmenopausal women are characterized by significantly lower levels of serum Zn concentration, whereas serum Zn and Sr levels were inversely associated with insulin resistance.

Diabetes and Exposure to Environmental Lead (Pb)

Although the increased incidence of type 2 diabetes since the 1950s is thought to be primarily due to coincident alterations in lifestyle factors, another potential contributing factor in industrialized countries is exposure of the population to environmental pollutants and industrial chemicals. Exposure levels of many environmental toxicants have risen in the same time-frame as the disease incidence. Of particular interest in this regard is the metal lead. Although overall lead exposure levels have diminished in recent decades, there is an under-recognized but persistent occurrence of lead exposure in poor underserved urban populations. Although the neural developmental pathologies induced by lead exposures have been well documented, very little is known about the effect of lead exposure on the incidence of chronic metabolic diseases such as type 2 diabetes. Although our understanding of the metabolic health effects of lead exposure is incomplete, there are studies in model systems and a small amount of epidemiological data that together suggest a deleterious effect of environmental lead exposure on metabolic health. This article reviews the human, animal and in vitro studies that have examined the effects of lead exposure on the development of diabetes and related metabolic conditions.

Blood Lead Levels and Decreased Kidney Function in a Population-Based Cohort

BACKGROUND

Environmental lead exposure has been associated with decreased kidney function, but evidence from large prospective cohort studies examining low exposure levels is scarce. We assessed the association of low levels of lead exposure with kidney function and kidney disease.

STUDY DESIGN

Prospective population-based cohort.

SETTING & PARTICIPANTS

4,341 individuals aged 46 to 67 years enrolled into the Malmö Diet and Cancer Study-Cardiovascular Cohort (1991-1994) and 2,567 individuals subsequently followed up (2007-2012).

PREDICTOR

Blood lead concentrations in quartiles (Q1-Q4) at baseline.

OUTCOMES

Change in estimated glomerular filtration rate (eGFR) between the baseline and follow-up visit based on serum creatinine level alone or in combination with cystatin C level. Chronic kidney disease (CKD) incidence (185 cases) through 2013 detected using a national registry.

MEASUREMENTS

Multivariable-adjusted linear regression models to assess associations between lead levels and eGFRs at baseline and follow-up and change in eGFRs over time. Cox regression was used to examine associations between lead levels and CKD incidence. Validation of 100 randomly selected CKD cases showed very good agreement between registry data and medical records and laboratory data.

RESULTS

At baseline, 60% of study participants were women, mean age was 57 years, and median lead level was 25 (range, 1.5-258) μg/L. After a mean of 16 years of follow-up, eGFR decreased on average by 6mL/min/1.73m² (based on creatinine) and 24mL/min/1.73m² (based on a combined creatinine and cystatin C equation). eGFR change was higher in Q3 and Q4 of blood lead levels compared with Q1 (P for trend = 0.001). The HR for incident CKD in Q4 was 1.49 (95% CI, 1.07-2.08) compared with Q1 to Q3 combined.

LIMITATIONS

Lead level measured only at baseline, moderate number of CKD cases, potential unmeasured confounding.

CONCLUSIONS

Low-level lead exposure was associated with decreased kidney function and incident CKD. Our findings suggest lead nephrotoxicity even at low levels of exposure.

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 lead levels and hypothalamic-pituitary-adrenal function in middle-aged individuals

Experimental and epidemiological studies suggested that exposure to lead (Pb) may influence the hypothalamic-pituitary-adrenal (HPA) axis. However, previous studies have yielded mixed results. We evaluated changes in basal salivary cortisol levels and acute cortisol responsivity to psychological stress in relation with blood Pb levels (BPb), in Caucasian individuals 50-67 years of age. Data were collected through the Study of Genetics, Stress and Cognitive Development (2004-2006). Diurnal basal and stress-reactive salivary cortisol levels were collected and BPb levels were determined using inductively coupled plasma mass spectroscopy. A total of 65 participants were included in the current study. General linear mixed models were used to assess the association between BPb level and change in cortisol secretion over time, for diurnal basal pattern and stress-reactive pattern, respectively. The geometric mean BPb was 2.70μg/dL (± 1.44) and two exposure groups were created based on the median value of 2.48µg/dL. No difference in geometric mean of salivary cortisol (µg/dL) at awakening was observed between High and Low BPb groups (0.23 (± 0.11) vs 0.20 (± 0.11), p = 0.36). The overall pattern of change in both diurnal basal (from the awakening to bedtime) and reactive salivary cortisol (during the stress induction protocol) did not differ between groups. In these middle-aged and older adults, we concluded that Pb exposure, within the range observed in the current study, was associated with neither diurnal nor stress-reactive cortisol secretion. Further investigation with larger datasets are needed to confirm our observations.

Costs of Health Damage from Atmospheric Emissions of Toxic Metals: Part 2-Analysis for Mercury and Lead

In this part of the series we explain the detailed literature review and the calculations of impacts and damage costs of mercury and lead. Methodology and general assumptions are explained in the companion article, Part 1 of this series, and the spreadsheet with the calculations is available as a supplementary file of Part 1.³ For mercury, the damage cost is 22,937 €₂₀₁₃ /kg if there is a no-effect threshold, 52,129 €₂₀₁₃ /kg if there is none; 91% is due to mortality from heart disease, the rest from loss of IQ points. For lead, the damage cost is 29,343 €₂₀₁₃ /kg, about 80% due to mortality and 20% due to IQ loss; there does not seem to be a no-effect threshold. These costs are per kg of emitted pollutant.

Maternal methylmercury exposure through rice ingestion and offspring neurodevelopment: A prospective cohort study

BACKGROUND

Dietary methylmercury intake can occur not only through fish ingestion but also through rice ingestion; however, rice does not contain the same beneficial micronutrients as fish.

OBJECTIVES

In rural China, where rice is a staple food, associations between prenatal methylmercury exposure (assessed using maternal hair mercury) and impacts on offspring neurodevelopment were investigated.

METHODS

A total of 398 mothers were recruited at parturition at which time a sample of scalp hair was collected. Offspring (n=270, 68%) were assessed at 12 months using the Bayley Scales of Infant Development-II, yielding age-adjusted scores for the Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI).

RESULTS

Among 270 mothers, 85% ingested rice daily, 41% never or rarely ingested fish/shellfish and 11% ingested fish/shellfish at least twice/weekly. Maternal hair mercury averaged 0.41μg/g (median: 0.39μg/g, range: 0.079-1.7μg/g). In unadjusted models, offspring neurodevelopment (both MDI and PDI) was inversely correlated with hair mercury. Associations were strengthened after adjustment for fish/shellfish ingestion, rice ingestion, total energy intake (kcal), and maternal/offspring characteristics for both the MDI [Beta: -4.9, 95% Confidence Interval (CI): -9.7, -0.12] and the PDI (Beta: -2.7, 95% CI: -8.3, 2.9), although confidence intervals remained wide for the latter.

CONCLUSIONS

For 12-month old offspring living in rural China, prenatal methylmercury exposure was associated with statistically significant decrements in offspring cognition, but not psychomotor development. Results expose potential new vulnerabilities for communities depending on rice as a staple food.

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.

Association of lead and cadmium exposure with frailty in US older adults

BACKGROUND

Environmental lead and cadmium exposure is associated with higher risk of several age-related chronic diseases, including cardiovascular disease, chronic kidney disease and osteoporosis. These diseases may lead to frailty, a geriatric syndrome characterized by diminished physiologic reserve in multiple systems with decreased ability to cope with acute stressors. However, no previous study has evaluated the association between lead or cadmium exposure and frailty.

METHODS

Cross-sectional study among individuals aged ≥ 60 years who participated in the third U.S. National Health and Nutrition Examination Survey and had either blood lead (N=5272) or urine cadmium (N=4887) determinations. Frailty was ascertained with a slight modification of the Fried criteria, so that individuals meeting ≥ 3 of 5 pre-defined criteria (exhaustion, low body weight, low physical activity, weakness and slow walking speed), were considered as frail. The association between lead and cadmium with frailty was evaluated using logistic regression with adjustment for relevant confounders.

RESULTS

Median (intertertile range) concentrations of blood lead and urine cadmium were 3.9 µg/dl (2.9-4.9) and 0.62 µg/l (0.41-0.91), respectively. The prevalence of frailty was 7.1%. The adjusted odds ratios (95% confidence interval) of frailty comparing the second and third to the lowest tertile of blood lead were, respectively, 1.40 (0.96-2.04) and 1.75 (1.33-2.31). Lead concentrations were also associated with the frequency of exhaustion, weakness and slowness. The corresponding odds ratios (95% confidence interval) for cadmium were, respectively, 0.97 (0.68-1.39) and 1.55 (1.03-2.32), but this association did not hold after excluding participants with reduced glomerular filtration rate: 0.70 (0.43-1.14) and 1.09 (0.56-2.11), respectively.

CONCLUSIONS

In the US older adult population, blood lead but not urine cadmium concentrations showed a direct dose-response relationship with frailty. These findings support that lead exposure increases frailty in older adults.

Study for Promotion of Health in Recycling Lead - Rationale and design

BACKGROUND

The level at which low-level lead exposure produces subclinical adverse health effects in adults remains to be established.

METHODS

The Study for Promotion of Health in Recycling Lead (SPHERL) will enroll 500 newly hired workers, whose blood lead during 2 years of follow-up is expected to increase from levels less than 2 μg/dl, as currently observed in the US population, to 20-30 μg/dl. The main outcome variables to be studied are (i) blood pressure (BP) analyzed as a continuous or categorical variable, both cross-sectionally and longitudinally, and using conventional and ambulatory BP measurement; (ii) indexes of glomerular and tubular renal function, (iii) heart rate variability analyzed in the frequency domain as measure of autonomous sympathetic modulation, (iv) peripheral nerve conductivity velocity, (v) neurocognitive performance, and (vi) quality of life. Expected outcomes. Assuming a 10-fold increase in blood lead, SPHERL will have sufficient statistical power to detect over 2 years a steepening of the age-related rise in systolic BP from 1 to 5 mmHg and a doubling of the age-related decline in the estimated glomerular filtration rate from 3.5 to 7.0 ml/min/1.73 m(2). The longitudinal design of our study complies with the temporality principle of the Bradford-Hill criteria for assessing possible causality between outcomes and exposure. SPHERL will attempt to resolve the apparent contradiction between general population studies showing associations between adverse health effects and low lead exposure with blood lead levels below 5 μg/dl and studies conducted in occupational cohorts indicating that adverse effects of lead exposure occur at much higher blood lead levels.

Risk factors for lead exposure in adult population in southern Brazil

In Brazil there is no systematic evaluation to access blood lead levels (BLL) in the general population and few studies with adults have been published. The aim of this study was to examine the socioeconomic, environmental, and lifestyle determinants of BLL in the adult Brazilian population. In total, 959 adults, aged 40 years or more, were randomly selected in a city in southern Brazil. Information on socioeconomic, dietary, lifestyle, and occupational background was obtained by interviews. A spatial analysis was conducted to discern whether there were any identifiable sources of exposure. BLL were measured by inductively coupled plasma-mass spectrometry. There was an adjustment for gender, age, race, education, income class, smoking status, alcohol consumption, occupation, and red meat or cow milk consumption (Model 1), and for occupation and gender (Model 2). The geometric mean of BLL was 1.97 μg/dl (95% CI: 1.9-2.04 μg/dl). In Model 1, BLL were positively associated with male gender, older age, and drinking and smoking habits, and less frequently with milk consumption. In Model 2, data showed higher BLL in non-white than white participants, in former smokers and individuals with current or former employment in lead (Pb) industries. The participants living in the area with more Pb industries had higher BLL (3.3 μg/dl) compared with those residing in other areas with no or fewer Pb industries (1.95 μg/dl). Despite the low BLL found in adults living in an urban area, Pb industries need to be monitored and regulatory laws implemented to prevent metal contamination in urban settings.

Environmental exposures, socioeconomics, disparities, and the kidneys

Kidney disease disproportionately affects racial and ethnic minority populations, the poor, and the socially disadvantaged. The excess risk of kidney disease among minority and disadvantaged populations can only be partially explained by an excess of diabetes, hypertension, and poor access to preventive care. Disparities in the environmental exposure to nephrotoxicants have been documented in minority and disadvantaged populations and may explain some of the excess risk of kidney disease. High-level environmental and occupational exposure to lead, cadmium, and mercury are known to cause specific nephropathies. However, there is growing evidence that low-level exposures to heavy metals may contribute to the development of CKD and its progression. In this article, we summarize the excess risk of environmental exposures among minority and disadvantaged populations. We also review the epidemiologic and clinical data linking low-level environmental exposure to lead, cadmium, and mercury to CKD and its progression. Finally, we briefly describe Mesoamerican nephropathy, an epidemic of CKD affecting young men in Central America, which may have occupational and environmental exposures contributing to its development.

Withania somnifera ameliorates lead-induced augmentation of adrenergic response in rat portal vein

OBJECTIVES

Present study was undertaken to elucidate the ameliorating potential of Withania somnifera root extract (WRE) against lead-induced augmentation of adrenergic response in rat portal vein.

MATERIALS AND METHODS

In-vitro studies were conducted on effect of lead alone and lead+WRE on rat-isolated portal vein while in-vivo studies were done in three groups of 12 rats each; Group-II and III received 0.5% lead acetate and 1.0% WRE + 0.5% lead acetate, respectively, in drinking water for 12 weeks whereas group-I served as control. Adrenaline and noradrenaline levels in brain and blood were determined by HPLC assay while vascular reactivity of portal vein to lead and WRE was determined by measuring the isometric tension.

RESULTS

Following in-vitro exposure, lead did not alter the contractile effect of phenylephrine. In-vivo studies revealed that contractile effect of lead on portal vein was significantly potentiated and it was antagonized by prazosin (10(-7) M) and WRE (1%). WRE treatment significantly reduced elevated blood noradrenaline (37.80%) and restored noradrenaline level in brain (39.39%) in lead-exposed animals. These values were almost comparable to the control group. But it failed to significantly affect the blood and brain adrenaline levels.

CONCLUSIONS

Results suggest that following pre-exposure of rats to WRE, lead-induced augmentation of alpha 1-adrenoceptors mediated response was reversed possibly by regulating catecholamine release from nerve endings. Thus, WRE may be useful in therapeutic management of lead-induced hypertension.

High body mass index reduces glomerular filtration rate decline in type II diabetes mellitus patients with stage 3 or 4 chronic kidney disease

Whether high body mass index (BMI) has an effect on progressive diabetic nephropathy in type II diabetes mellitus (DM) patients with chronic kidney disease (CKD) stage 3 or 4 remains unclear. This prospective study aimed to investigate the relationship between BMI and progression of renal function deterioration in type II DM patients with CKD stage 3 or 4.A total of 105 type II DM patients with CKD stage 3 or 4 participated in this 24-month prospective observational study. Patients were divided into 3 groups according to BMI as follows: normal group, BMI of 18.5-22.9 kg/m; overweight group, BMI of 23-24.9 kg/m; and obese group, BMI of ≥25 kg/m. The primary end point was a 2-fold elevation in serum creatinine levels (measured twice with a 1-month interval) from baseline values, need for long-term dialysis, or death during the 24-month observation period.In the linear regression analysis with the stepwise method, each 1 kg/m increase in BMI led to an increase of 0.32 mL min × 1.73 m in the estimated glomerular filtration rate (95% confidence interval, CI, 0.01-0.62; P = 0.04) during the 24-month study period. Moreover, multivariate Cox regression analysis showed that compared with the obese group, the normal BMI group (hazard ratio = 2.76, 95% CI : 1.27-6; P = 0.01) achieved the primary outcome after adjusting for other factors.In this 24-month prospective observational study, we showed that BMI of ≥25 kg/m was a protective factor for renal function deterioration in type II DM patients with CKD stage 3 or 4.

Occupational determinants of cumulative lead exposure: analysis of bone lead among men in the VA normative aging study

OBJECTIVES

To examine the relation between occupation and cumulative lead exposure-assessed by measuring bone lead-in a community-dwelling population.

METHOD

We measured bone lead concentration with K-shell X-Ray Fluorescence in 1320 men in the Normative Aging Study. We categorized job titles into 14 broad US Census Bureau categories. We used ordinary least squares regression to estimate bone lead by job categories adjusted for other predictors.

RESULTS

Service workers, construction, and extractive craft workers and installation, maintenance, and repair craft workers had the highest bone lead concentrations. Including occupations significantly improved the overall model (P < 0.001) and reduced by 15% to 81% the association between bone lead and education categories.

CONCLUSION

Occupation significantly predicts cumulative lead exposure in a community-dwelling population and accounts for a large proportion of the association between education and bone lead.

Incident ESRD among participants in a lead surveillance program

BACKGROUND

Very high levels of lead can cause kidney failure; data about renal effects at lower levels are limited.

STUDY DESIGN

Cohort study, external (vs US population) and internal (by exposure level) comparisons.

SETTINGS & PARTICIPANTS

58,307 men in an occupational surveillance system in 11 US states.

PREDICTOR

Blood lead levels.

OUTCOME

Incident end-stage renal disease determined by matching the cohort with the US Renal Data System (n=302).

MEASUREMENTS

Blood lead categories were 0-<5, 5-<25, 25-<40, 40-51, and >51 μg/dL, defined by highest blood lead test result. One analysis for those with data for race (31% of cohort) and another for the whole cohort after imputing race.

RESULTS

Median follow-up was 12 years. Among those with race information, the end-stage renal disease standardized incidence ratio (SIR; US population as referent) was 1.08 (95% CI, 0.89-1.31) overall. The SIR in the highest blood lead category was 1.47 (95% CI, 0.98-2.11), increasing to 1.56 (95% CI, 1.02-2.29) for those followed up for 5 or more years. For the entire cohort (including those with race imputed), the overall SIR was 0.92 (95% CI, 0.82-1.03), increasing to 1.36 (95% CI, 0.99-1.73) in the highest blood lead category (SIR of 1.43 [95% CI, 1.01-1.85] in those with ≥5 years' follow-up). In internal analyses by Cox regression, rate ratios for those with 5 or more years' follow-up in the entire cohort were 1.0 (0-<5 and 5-<25 μg/dL categories combined) and 0.92, 1.08, and 1.96 for the 25-<40, 40-51, and >51 μg/dL categories, respectively (P for trend=0.003). The effect of lead was strongest in nonwhites.

LIMITATIONS

Lack of detailed work history, reliance on only a few blood lead tests per person to estimate level of exposure, lack of clinical data at time of exposure.

CONCLUSIONS

Data suggest that current US occupational limits on blood lead levels may need to be strengthened to avoid kidney disease.

Blood metals concentration in type 1 and type 2 diabetics

Mechanisms for the onset of diabetes and the development of diabetic complications remain under extensive investigations. One of these mechanisms is abnormal homeostasis of metals, as either deficiency or excess of metals, can contribute to certain diabetic outcomes. Therefore, this paper will report the blood levels of chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), mercury (Hg), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) in subjects with type 1 diabetes (n = 192, mean age 48.8 years, mean disease duration 20.6 years), type 2 diabetes (n = 68, mean age 68.4 years, mean disease duration 10.2 years), and in control subjects (n = 59, mean age 57.2 years), and discuss the results indicating their possible role in diabetes. The metal concentrations were measured by sector field inductively coupled plasma mass spectrometry after microwave-induced acid digestion of blood samples. The accuracy was checked using a blood-based certified reference material, and recoveries of all elements were in the range of 92-101 % of certified values. Type 1 diabetes was found to be associated with Cr (p = 0.02), Mn (p < 0.001), Ni (p < 0.001), Pb (p = 0.02), and Zn (p < 0.001) deficiency, and type 2 diabetes with Cr (p = 0.014), Mn (p < 0.001), and Ni (p < 0.001) deficiency. These deficiencies were appreciated also subdividing the understudied patients for gender and age groups. Furthermore, in type 1 diabetes, there was a positive correlation between Pb and age (p < 0.001, ρ = 0.400) and Pb and BMI (p < 0.001, ρ = 0.309), while a negative correlation between Fe and age (p = 0.002, ρ = -0.218). In type 2 diabetes, there was a negative correlation between Fe and age (p = 0.017, ρ = -0.294) and Fe and BMI (p = 0.026, ρ = -0.301). Thus, these elements may play a role in both forms of diabetes and combined mineral supplementations could have beneficial effects.