Association of urinary exposure to multiple metal(loid)s with kidney function from a national cross-sectional study

Sex-specific impact of polycyclic aromatic hydrocarbons and metals on renal function in U.S. adults: Mediating roles of inflammation, oxidative stress and aging

BACKGROUND

Previous research has established associations between polycyclic aromatic hydrocarbons (PAHs), heavy metals (HMs), and kidney damage. However, the impact of PAHs and HMs mixtures on chronic kidney disease (CKD), particularly gender differences, remains unclear.

METHODS

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) data spanning 2003-2016 to investigate the association between PAHs and HMs with CKD, employing weighted logistic regression analyses. This exploration was complemented by gender-stratified restricted cubic spline (RCS) methods. Multiple mixture analysis models were applied to evaluate the combined effects of PAHs and HMs on kidney damage. Mediation analyses were conducted to explore the mediating effects of inflammation, oxidative stress, and aging biomarkers.

RESULTS

The results of the mixture analysis indicated a significant positive correlation between PAHs and HMs with the CKD risk in the general population, with cadmium (Cd), lead (Pb), and 2-naphthalene (2-NAP) contributing prominently to this relationship. These findings were consistent in the female subgroup. However, no effect of co-exposure to PAHs and HMs on CKD and urine albumin-to-creatinine ratio (UACR) was observed in the male subgroup. PAHs and HMs mixtures with CKD risk mediated by the biological age (BA) and phenotypic age (PA), with mediation proportions of 44.1 % and 61.4 %, respectively.

CONCLUSION

The study reveals a significant association between PAHs and HMs mixtures and CKD in the US population, with females being particularly susceptible. Biological aging emerges as a primary mediator in this relationship. Further prospective cohort studies are required to validate these findings.

Association between urinary heavy metal/trace element concentrations and kidney function: a prospective study

Background

Chronic kidney disease (CKD) is an important public health problem. Although cross-sectional studies have identified many heavy metals/trace elements associated with reduced kidney function, prospective studies are needed to determine the pathogenic role of these elements in the development and progression of CKD.

Methods

To explore the association between baseline urinary heavy metal/trace element concentrations and long-term impaired kidney function (IKF)/CKD, as well as the incidence of rapid decline in kidney function in a population-based exploratory prospective study, with mean age 51.9 years at baseline whose urinary trace elements concentrations have been determined by inductively coupled plasma mass spectrometry. IKF was defined by a reduced estimated glomerular filtration rate (eGFR) between 60 and 90 mL/min/1.73 m2, and CKD was defined as an eGFR <60 mL/min/1.73 m2. Rapid eGFR decline was defined as a decrease ≥3 mL/min/1.73 m2/year.

Results

Over a mean follow-up of 12.5 years, 123 participants (2.6%) experienced rapid decline in kidney function, and 1455 (31.7%) developed IKF or CKD. After adjusting for covariates including baseline eGFR, we found that urinary vanadium [hazard ratio (HR) = 1.07, 1.03-1.12], cobalt (HR = 1.69, 1.21-2.37), nickel (HR = 1.19, 1.08-1.3), copper (HR = 1.03, 1.01-1.06), selenium (HR = 1.33, 1.02-1.73), molybdenum (HR = 1.48, 1.2-1.82) and iodine (HR = 1.1, 1.02-1.2) were associated with an increased risk of new incident IKF or CKD cases during the follow-up. Also, urinary copper [odds ratio (OR) = 1.12, 1.04-1.21], silver (OR = 1.83, 1-3.35), molybdenum (OR = 1.02, 1.01-1.04) and cadmium (OR = 1.05, 1.01-1.09) were associated with an increased risk of rapid eGFR decline.

Conclusion

In the general population, several urinary heavy metals/trace elements are associated with a rapid decline in kidney function or new cases of IKF/CKD.

Plasma myeloperoxidase interactions with cadmium, lead, arsenic, and selenium and their impact on chronic kidney disease

Myeloperoxidase (MPO) is an oxidative stress biomarker, with elevated MPO levels linked to chronic kidney disease (CKD) progression. Metal exposure is a risk factor for CKD, and is also correlated to MPO expression, with specific MPO genotypes linked to MPO expression. Therefore, we examined whether MPO plasma levels or MPO polymorphisms were linked to CKD, and explored whether these factors modified associations between CKD and metal concentrations. Accordingly, we recruited 395 age- and sex-matched controls and 215 patients with CKD (persistent estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 for a minimum of 12 weeks without hemodialysis). We identified no associations between several MPO genotypes and CKD. However, after multivariate adjustment, plasma MPO concentrations were positively correlated with CKD odds ratio (OR) = 5.87 (95 % confidence interval [CI]: 3.14-10.96). Significant additive interactions were observed between high plasma MPO concentrations and elevated blood cadmium (Cd) and lead (Pb) levels, and total urinary arsenic (As), or low plasma selenium (Se) concentrations, leading to increased ORs for CKD, with significant synergy indices recorded. High plasma MPO concentrations also showed multiplicative interactions with elevated blood Pb levels or low plasma Se concentrations, which increased the ORs for CKD (p-values = 0.005 and 0.009, respectively). Our study is the first to show a significant interaction between plasma MPO concentration and metals affecting the OR of CKD.

Association Between Urinary Metal Levels and Chronic Kidney Dysfunction in Rural China: A Study on Sex-Specific Differences

BACKGROUND

While current epidemiological studies have documented associations between environmental metals and renal dysfunction, the majority have concentrated on plasma metal levels. The relationship between urinary metal exposure and chronic kidney disease (CKD) remains contentious, particularly within specific demographic groups.

METHODS

This cross-sectional study included 2919 rural Chinese adults recruited between 2018 and 2019. Urine metals were measured by ICP-MS. Least absolute shrinkage and selection operator (LASSO) regression was employed to identify metals significantly associated with CKD. Then, we used binary logistic regression, along with restricted cubic spline (RCS) models, to assess the individual exposure effects of specific metals on CKD. Quantile g-computation, weighted quantile sum regression, and Bayesian kernel machine regression (BKMR) models were applied to evaluate combined effects of metal exposures on CKD. Gender-stratified analyses were also conducted to explore these associations.

RESULTS

LASSO identified seven metals (V, Cu, Rb, Sr, Ba, W, Pb) with significant impacts on CKD. In single-metal models, Cu and W exhibited a positive correlation with CKD, whereas V, Rb, Sr, Ba, and Pb showed significant negative correlations (all p < 0.05). RCS analysis revealed nonlinear associations between V, Cu, Ba, Pb, and CKD (all p-nonlinear < 0.05). In the multi-metal model, quantile-based g-computation demonstrated a collective negative association with CKD risk for the seven mixed urinary metal exposures (OR (95% CI) = -0.430 (-0.656, -0.204); p < 0.001), with V, Rb, Sr, Ba, and Pb contributing to this effect. The WQS model analysis further confirmed this joint negative association (OR (95% CI): -0.885 (-1.083, -0.899); p < 0.001), with V as the main contributor. BKMR model analysis indicated an overall negative impact of the metal mixture on CKD risk. Interactions may exist between V and Cu, as well as Cu and Sr and Pb. The female subgroup in the BKMR model demonstrated consistency with the overall association.

CONCLUSIONS

Our study findings demonstrate a negative association between the urinary metal mixture and CKD risk, particularly notable in females. Joint exposure to multiple urinary metals may involve synergistic or antagonistic interactions influencing renal function. Further research is needed to validate these observations and elucidate underlying mechanisms.

Investigating the relationship of co-exposure to multiple metals with chronic kidney disease: An integrated perspective from epidemiology and adverse outcome pathways

Systematic studies on the associations between co-exposure to multiple metals and chronic kidney disease (CKD), as well as the underlying mechanisms, remain insufficient. This study aimed to provide a comprehensive perspective on the risk of CKD induced by multiple metal co-exposures through the integration of occupational epidemiology and adverse outcome pathway (AOP). The study participants included 401 male mine workers whose blood metal, β2-microglobulin (β2-MG), and cystatin C (Cys-C) levels were measured. Generalized linear models (GLMs), quantile g-computation models (qgcomp), least absolute shrinkage and selection operator (LASSO), and bayesian kernel machine regression (BKMR) were utilized to identify critical nephrotoxic metals. The mean concentrations of lead, cadmium, mercury, arsenic, and manganese were 191.93, 3.92, 4.66, 3.11, 11.35, and 16.33 µg/L, respectively. GLM, LASSO, qgcomp, and BKMR models consistently identified lead, cadmium, mercury, and arsenic as the primary contributors to kidney toxicity. Based on our epidemiological analysis, we used a computational toxicology method to construct a chemical-genetic-phenotype-disease network (CGPDN) from the Comparative Toxicogenomics Database (CTD), DisGeNET, and GeneCard databases, and further linked key events (KEs) related to kidney toxicity from the AOP-Wiki and PubMed databases. Finally, an AOP framework of multiple metals was constructed by integrating the common molecular initiating events (reactive oxygen species) and KEs (MAPK signaling pathway, oxidative stress, mitochondrial dysfunction, DNA damage, inflammation, hypertension, cell death, and kidney toxicity). This is the first AOP network to elucidate the internal association between multiple metal co-exposures and CKD, providing a crucial basis for the risk assessment of multiple metal co-exposures.

Unveiling the interaction and combined effects of multiple metals/metalloids exposure to TNF-α and kidney function in adults using bayesian kernel machine regression and quantile-based G-computation

BACKGROUND

Exposure to multiple metals may cause adverse effects, particularly in the kidneys. However, studies on the combined and interaction effects of metal mixtures on human health remain limited.

OBJECTIVE

The study aims to evaluate the interaction between metals and assess the combined effects of exposure to metal mixtures on tumor necrosis factor-alpha (TNF-α) levels and kidney function METHODS: Particular emphasis has been placed on the impact of various metals, including arsenic (As), cadmium (Cd), lead (Pb), as well as essential trace elements, such as cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn), on human health and their potential collective influence on both TNF-α and kidney function. This cross-sectional study analyzed the data of 421 adults who underwent a health examination. Generalized linear model (GLM), Bayesian kernel machine regression (BKMR), and quantile-based G-computation (qgcomp) were used to evaluate the association and joint effects between the metals and TNF-α, as well as kidney function.

RESULTS

Increased concentrations of As (β = 0.11, 95 % CI = 0.05, 0.17) and Pb (β = 0.30, 95 % CI = 0.23, 0.37) in the blood were associated with elevated levels of TNF-α, while elevated Cu (β = -0.42, 95 % CI = -0.77, -0.07) levels were linked to a significant reduction in TNF-α. The overall effect of metals mixture showed a significant association with a decline in eGFR and an increase TNF-α in the BKMR model. Qgcomp analysis of the metals mixture (β = -0.06, 95 % CI = -0.07, -0.05) indicated that As, Pb, and Zn were the primary contributors to the reduction in eGFR, while As and Pb were the major contributors in metals mixture (β = 0.12, 95 % CI = 0.08, 0.15) to the elevation of TNF-α levels.

CONCLUSION

Exposure to multiple metals could have joint association with the TNF-α levels and kidney function. Furthermore, TNF-α could act as a mediator between metal mixtures and eGFR.

Heavy metals and elderly kidney health: A multidimensional study through Enviro-target Mendelian Randomization

Chronic Kidney Disease (CKD), closely linked to environmental factors, poses a significant public health challenge. This study, based on 529 triple-repeated measures from key national environmental pollution area and multiple gene-related public databases, employs various epidemiological and bioinformatics models to assess the impact of combined heavy metal exposure (Chromium [Cr], Cadmium [Cd], and Lead [Pb]) on early renal injury and CKD in the elderly. Introducing the novel Enviro-Target Mendelian Randomization method, our research explores the causal relationship between metals and CKD. The findings indicate a positive correlation between increased levels of metal and renal injury, with combined exposure caused renal damage more significantly than individual exposure. The study reveals that metals primarily influence CKD development through oxidative stress and metal ion resistance pathways, focusing on three related genes (SOD2, MPO, NQO1) and a transcription factor (NFE2L2). Metals were found to regulate oxidative stress levels in the body by increasing the expression of SOD2, MPO, NQO1, and decreasing NFE2L2, leading to CKD onset. Our research establishes a new causal inference framework linking environmental pollutants-pathways-genes-CKD, assessing the impact and mechanisms of metal exposure on CKD. Future studies with more extensive in vitro evidence and larger population are needed to validate.

Exposure to synthesized tribromobisphenol A and critical effects: Metabolic pathways, disease signature, and benchmark dose derivation

2,2',6-Tribromobisphenol A (Tri-BBPA), the main debrominated congener of tetrabromobisphenol A (TBBPA), is ubiquitous in the environment and human body but with unknown toxicity. Tri-BBPA was synthesized and applied to investigate its sub-chronic exposure effects on 28 organ coefficients and clinical health indicators related to liver function, kidney function, and cardiovascular system function in female mice. Results showed that the liver was the targeted organ of Tri-BBPA exposure. Compared to the control group, the changes in liver coefficient, cholinesterase, total protein, albumin, γ-glutamyl transpeptidase, lactate dehydrogenase, and creatine kinase levels ranged from -61.2 % to 35.5 % in the high-exposed group. Creatine kinase was identified as a critical effect indicator of Tri-BBPA exposure. Using the Bayesian benchmark dose derivation method, a lower reference dose than TBBPA was established for Tri-BBPA (10.6 μg/kg-day). Serum metabolomics revealed that Tri-BBPA exposure may primarily damage the liver by disrupting tryptophan metabolism related to L-alanine, tryptamine, 5-hydroxyindoleacetic acid, and 5-methoxyindoleacetate in liver cells and leading to liver dysfunction. Notably, epilepsy, schizophrenia, early preeclampsia, and late-onset preeclampsia were the top six enriched diseases, suggesting that the nervous system may be particularly affected by Tri-BBPA exposure. Our findings hinted a non-negligible health risk of exposure to debrominated products of TBBPA.

Complex interplay of heavy metals and renal injury: New perspectives from longitudinal epidemiological evidence

BACKGROUND

Epidemiological studies have reported associations between heavy metals and renal function. However, longitudinal studies are required to further validate these associations and explore the interactive effects of heavy metals on renal function and their directional influence.

METHOD

This study, conducted in Northeast China from 2016 to 2021, included a four-time repeated measures design involving 384 participants (1536 observations). Urinary concentrations of chromium (Cr), cadmium (Cd), manganese (Mn), and lead (Pb) were measured, along with renal biomarkers including urinary microalbumin (umAlb), urinary albumin-to-creatinine ratio (UACR), N-acetyl-β-D-glucosaminidase (NAG), and β2-microglobulin (β2-MG) levels. Estimated glomerular filtration rate (eGFR) was calculated. A Linear Mixed Effects Model (LME) examined the association between individual metal exposure and renal biomarkers. Subsequently, Quantile g-computation and Bayesian Kernel Machine Regression (BKMR) models assessed the overall effects of heavy metal mixtures. Marginal Effect models examined the directional impact of metal interactions in the BKMR on renal function.

RESULT

Results indicate significant impacts of individual and combined exposures of Cr, Cd, Pb, and Mn on renal biomarkers. Metal interactions in the BKMR model were observed, with synergistic effects of Cd-Cr on NAG, umAlb, UACR; Cd-Pb on NAG, UACR; Pb-Cr on umAlb, UACR, eGFR-MDRD, eGFR-EPI; and an antagonistic effect of Mn-Pb-Cr on UACR.

CONCLUSION

Both individual and combined exposures to heavy metals are associated with renal biomarkers, with significant synergistic interactions leading to renal damage. Our findings elucidate potential interactions among these metals, offering valuable insights into the mechanisms linking multiple metal exposures to renal injury.

Associations among environmental exposure to trace elements and biomarkers of early kidney damage in the pediatric population

BACKGROUND

In kidney damage, molecular changes can be used as early damage kidney biomarkers, such as Kidney Injury Molecule-1 and Neutrophil gelatinase-associated lipocalin. These biomarkers are associated with toxic metal exposure or disturbed homeostasis of trace elements, which might lead to serious health hazards. This study aimed to evaluate the relationship between exposure to trace elements and early damage kidney biomarkers in a pediatric population.

METHODS

In Tlaxcala, a cross-sectional study was conducted on 914 healthy individuals. The participants underwent a medical review and a socio-environmental questionnaire. Five early damage kidney biomarkers were determined in the urine with Luminex, and molybdenum, copper, selenium, nickel, and iodine were measured with ICP-Mass.

RESULTS

The eGFR showed a median of 103.75 mL/min/1.73 m2. The median levels for molybdenum, copper, selenium, nickel, and iodine were 24.73 ng/mL, 73.35 ng/mL, 4.78 ng/mL, 83.68 ng/mL, and 361.83 ng/mL, respectively. Except for molybdenum and nickel, the other trace elements had significant associations with the eGFR and the early kidney damage biomarkers. Additionally, we report the association of different exposure scenarios with renal parameters.

DISCUSSION

and Conclusions. Among the explored metals, exposure to Cu and iodine impairs renal function. In contrast, Se may manifest as a beneficial metal. Interactions of Mo-Se and Mo-Iodine seem to alter the expression of NGAL; Mo-Cu for CLU; Mo-Cu, Mo-Se, and Mo-iodine for Cys-C and a-1MG; and Mo-Cu and Mo-iodine for KIM-1; were noticed. Our study could suggest that trace element interactions were associated with early kidney damage biomarkers.

Metabolomics perspectives into the co-exposure effect of polycyclic aromatic hydrocarbons and metals on renal function: A meet-in-the-middle approach

Studies on the dose effects of kidney impairment and metabolomes in co-exposure to polycyclic aromatic hydrocarbons (PAHs) and metals are limited. We aimed to identify overall associations and metabolic perturbations in 130 participants (53 petrochemical workers and 77 controls) exposed to a PAHs-metals mixture in Southern China. The urinary 7 hydroxylated PAHs and 15 metal(loid)s were determined, and serum creatinine, beta-2 microglobulin, and estimated glomerular filtration rate were health outcomes. The liquid chromatography-mass spectrometry-based method was applied to serum metabolomics. Generalized weighted quantile sum (gWQS) regressions were used to estimate the overall dose-response relationships, and pathway analysis, "meet-in-the-middle" approach, and mediation effect analyses were conducted to identify potential metabolites and biological mechanisms linking exposure with nephrotoxic effects. Our results indicated that renal function reduction was associated with a PAHs-metals mixture in a dose-dependent manner, and 1-hydroxynaphthalene and copper were the most predominant contributors among the two families of pollutants. Furthermore, the metabolic disruptions associated with the early onset of kidney impairment induced by the combination of PAHs and metals encompassed pathways such as phenylalanine-tyrosine-tryptophan biosynthesis, phenylalanine metabolism, and alpha-linolenic acid metabolism. In addition, the specifically identified metabolites demonstrated excellent potential as bridging biomarkers connecting the reduction in renal function with the mixture of PAHs and metals. These findings shed light on understanding the overall associations and metabolic mechanism of nephrotoxic effects of co-exposure to PAHs and metals.

Exposure to cadmium and lead is associated with diabetic kidney disease in diabetic patients

BACKGROUND

Cadmium (Cd) and lead (Pb) exhibit nephrotoxic activity and may accelerate kidney disease complications in diabetic patients, but studies investigating the relation to diabetic kidney disease (DKD) have been limited. We aimed to examine the associations of Cd and Pb with DKD in diabetic patients.

METHODS

3763 adults with blood metal measurements and 1604 adults with urinary ones who were diabetic from National Health and Nutrition Examination Survey (NHANES) 2007-2016 were involved. Multivariate logistic regression models were used to analyze the associations of blood Cd (BCd), blood Pb (BPb), urinary Cd (UCd), and urinary Pb (UPb) with DKD.

RESULTS

BPb, BCd, and UCd levels were higher among participants with DKD than diabetics without nephropathy, but UPb performed the opposite result. BPb and UCd were significantly associated with DKD in the adjusted models (aOR, 1.17 (1.06, 1.29);1.52 (1.06, 2.02)). Participants in the 2nd and 3rd tertiles of BPb and BCd levels had higher odds of DKD, with a significant trend across tertiles, respectively (all P-trend < 0.005). Multiplication interaction was also identified for BPb and BCd (P for interaction = 0.044).

CONCLUSION

BPb, BCd, and UCd were positively associated with the risk of DKD among diabetic patients. Furthermore, there were the dose-response relationship and multiplication interaction in the associations of BPb, BCd with DKD.

Association of cadmium environmental exposure with chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

Several observational studies investigated the relationship between environmental cadmium exposure and risk of chronic kidney disease (CKD). However, results from epidemiological studies are conflicting and wide variabilities have been reported.

OBJECTIVES

We conducted a meta-analysis to evaluate the relationship between environmental cadmium exposure and CKD risk, as assessed by decreased estimated Glomerular Filtration Rate (eGFR) in adults.

METHODS

PubMed, Embase and the Cochrane library databases were searched for studies published up to July 2023. A random-effects model using the restricted maximum likelihood (REML) method was used to calculate the overall estimate to assess the association between cadmium exposure and eGFR. Subgroup analysis, funnel plot, Egger's test, and the trim-and-fill method were also conducted.

RESULTS

Thirty-one articles, 3 cohorts, 2 case-control and 26 cross-sectional studies, across 8 countries, involving 195.015 participants were included. The meta-analysis demonstrated an inverse association between high cadmium exposure and eGFR levels (standardized regression coefficient β = -0.09; 95 % CI = -0.15, -0.04). The subgroup analysis showed that the inverse association was significantly higher for blood cadmium exposure (β = -0.12; 95 % CI = -0.18, -0.06) than for urinary concentrations (β = -0.04; 95 % CI: -0.10, 0.03) or dietary exposure (β = -0.03; 95 % CI = -0.19, 0.14). Stratified analysis by different study design also showed an inverse association between cadmium exposure and eGFR, more evident in the cross-sectional studies (β = -0.11; 95 % CI = -0.18, -0.03) than in the cohort (β = -0.05; 95 % CI = -0.26, 0.17) and in the case-control studies (β = -0.05; 95 % CI = -0.32, 0.21).

DISCUSSION

Our meta-analysis indicated that environmental cadmium exposure is associated with increased risk of CKD, as assessed by decreased eGFR, and this association is more evident for blood cadmium concentrations than for urinary concentrations or dietary exposure. Nevertheless, additional high quality prospective studies are needed to confirm the association between cadmium exposure and risk of CKD.

Metal mixture exposure and the risk for immunoglobulin A nephropathy: Evidence from weighted quantile sum regression

Immunoglobulin A nephropathy (IgAN) is the most common type of glomerulonephritis in adults worldwide. Environmental metal exposure has been reported to be involved in the pathogenic mechanisms of kidney diseases, yet no further epidemiological study has been conducted to assess the effects of metal mixture exposure on IgAN risk. In this study, we conducted a matched case‒control design with three controls for each patient to investigate the association between metal mixture exposure and IgAN risk. A total of 160 IgAN patients and 480 healthy controls were matched for age and sex. Plasma levels of arsenic, lead, chromium, manganese, cobalt, copper, zinc, and vanadium were measured using inductively coupled plasma mass spectrometry. We used a conditional logistic regression model to assess the association between individual metals and IgAN risk, and a weighted quantile sum (WQS) regression model to analyze the effects of metal mixtures on IgAN risk. Restricted cubic splines were used to evaluate overall associations between plasma metal concentrations and estimated glomerular filtration rate (eGFR) levels. We observed that except for Cu, all the metals analyzed were nonlinearly associated with decreased eGFR, and higher concentrations of arsenic and lead were associated with elevated IgAN risk in both single-metal [3.29 (1.94, 5.57), 6.10 (3.39, 11.0), respectively] and multiple-metal [3.04 (1.66, 5.57), 4.70 (2.47, 8.97), respectively] models. Elevated manganese [1.76 (1.09, 2.83)] levels were associated with increased IgAN risk in the single-metal model. Copper was inversely related to IgAN risk in both single-metal [0.392 (0.238, 0.645)] and multiple-metal [0.357 (0.200, 0.638)] models. The WQS indices in both positive [2.04 (1.68, 2.47)] and negative [0.717 (0.603, 0.852)] directions were associated with IgAN risk. Lead, arsenic, and vanadium contributed significant weights (0.594, 0.195, and 0.191, respectively) in the positive direction; copper, cobalt, and chromium carried significant weights (0.538, 0.253, and 0.209, respectively). In conclusion, metal exposure was related to IgAN risk. Lead, arsenic, and copper were all significantly weighted factors of IgAN development, which may require further investigation.