Association of plasma and urine metals levels with kidney function: A population-based cross-sectional study in China

Human molybdenum exposure risk in industrial regions of China: New critical effect indicators and reference dose

Evidence increasingly suggests molybdenum exposure at environmental levels is still associated with adverse human health, emphasizing the necessity to establish a more protective reference dose (RfD). Herein, we conducted a study measuring 15 urinary metals and 30 clinical health indicators in 2267 participants residing near chemical enterprises across 11 Chinese provinces to investigate their relationships. The kidney and cystatin-C emerged as the most sensitive organ and critical effect indicator of molybdenum exposure, respectively. Odds of cystatin-C-defined chronic kidney disease (CKD) in the highest quantile of molybdenum exposure significantly increased by 133.5% (odds ratio [OR]: 2.34, 95% CI: 1.78, 3.11) and 75.8% (OR: 1.76, 95% CI: 1.24, 2.49) before and after adjusting for urinary 14 metals, respectively. Intriguingly, cystatin-C significantly mediated 15.9-89.5% of molybdenum's impacts on liver and lung function, suggesting nephrotoxicity from molybdenum exposure may trigger hepatotoxicity and pulmonary toxicity. We derived a new RfD for molybdenum exposure (0.87 μg/kg-day) based on cystatin-C-defined estimated glomerular filtration rate by employing Bayesian Benchmark Dose modeling analysis. This RfD is significantly lower than current exposure guidance values (5-30 μg/kg-day). Remarkably, >90% of participants exceeded the new RfD, underscoring the significant health impacts of environmental molybdenum exposure on populations in industrial regions of China.

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.

Human Health Effects of Oral Exposure to Chromium: A Systematic Review of the Epidemiological Evidence

The toxicity and carcinogenicity of hexavalent chromium via the inhalation route is well established. However, a scientific debate has arisen about the potential effects of oral exposure to chromium on human health. Epidemiological studies evaluating the connection between ingested chromium and adverse health effects on the general population are limited. In recent years, a wealth of biomonitoring studies has emerged evaluating the associations between chromium levels in body fluids and tissues and health outcomes. This systematic review brings together epidemiological and biomonitoring evidence published over the past decade on the health effects of the general population related to oral exposure to chromium. In total, 65 studies were reviewed. There appears to be an inverse association between prenatal chromium exposure and normal fetal development. In adults, parameters of oxidative stress and biochemical alterations increase in response to chromium exposure, while effects on normal renal function are conflicting. Risks of urothelial carcinomas cannot be overlooked. However, findings regarding internal chromium concentrations and abnormalities in various tissues and systems are, in most cases, controversial. Environmental monitoring together with large cohort studies and biomonitoring with multiple biomarkers could fill the scientific gap.

Associations between multiple metal exposure and fertility in women: A nested case-control study

Metal pollution can cause a decline in female fertility, however, previous studies have focused more on the effect of a single metal on fertility. In this study, we evaluated the effect of metal mixtures on female fertility based on nested case-control samples. The plasma levels of 22 metal elements from 180 women were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Minimum absolute contraction and selection operator (LASSO) penalty regression selected metals with the greatest influence on clinical outcome. Logistic regression was used to analyze the correlation between single metals and fertility while a Bayesian kernel function regression (BKMR) model was used to analyze the effect of mixed metals. Eight metals (Calcium (Ca), Chromium (Cr), Cobalt (Co), Copper (Cu), Zinc (Zn), Rubidium (Rb), Strontium (Sr) and Zirconium (Zr)) were selected by LASSO regression for subsequent analysis. After adjusting for covariates, the logistic model showed that Cu (Odds Ratio(OR):0.33, 95% CI: 0.13 - 0.84) and Co (OR:0.38, 95% CI: 0.15 -0.94) caused a significant reduction in fertility, and identified the protective effect of Zn (OR: 2.96, 95% CI:1.21 -7.50) on fertility. Trend tests showed that increased Cr, Cu, and Rb levels were associated with reduced fertility. The BKMR model showed that Cr, Co, Cu, and Rb had a nonlinear relationship with fertility decline when controlling for the concentrations of other metals and suggested that Cu and Cr might exert an influence on fertility. Analysis showed a negative correlation between Cu, Cr, Co, Rb, and fertility, and a positive correlation between Zn and fertility. Furthermore, we found evidence for the interaction between Cu and Cr. Our findings require further validation and may identify new mechanisms in the future.

Associations Between Individual and Combined Metal Exposures in Whole Blood and Kidney Function in U.S. Adults Aged 40 Years and Older

The effects of metal exposure on kidney function have been reported in previous literature. There is limited and inconsistent information on the associations between individual and combined exposures to metals and kidney function among the middle-aged and older population. The aim of this study was to clarify the associations of exposure to individual metals with kidney function while accounting for potential coexposure to metal mixtures and to evaluate the joint and interactive associations of blood metals with kidney function. A total of 1669 adults aged 40 years and older were enrolled in the present cross-sectional study using the 2015-2016 National Health and Nutrition Examination Survey (NHANES). Single-metal and multimetal multivariable logistic regression models, quantile G-computation, and Bayesian kernel machine regression models (BKMR) were fitted to explore the individual and joint associations of whole blood metals [lead (Pb), cadmium (Cd), mercury (Hg), cobalt (Co), manganese (Mn), and selenium (Se)] with the odds of decreased estimated glomerular filtration rate (eGFR) and albuminuria. A decreased eGFR was defined as an eGFR ≤ 60 mL/min per 1.73 m2, and albuminuria was categorized as a urinary albumin-creatinine ratio (UACR) of ≥ 30.0 mg/g. The results from quantile G-computation and BKMR indicated positive associations between exposure to the metal mixture and the prevalence of decreased eGFR and albuminuria (all P values < 0.05). These positive associations were mainly driven by blood Co, Cd, and Pb. Furthermore, blood Mn was identified as an influential element contributing to an inverse correlation with kidney dysfunction within metal mixtures. Increasing blood Se levels were negatively associated with the prevalence of decreased eGFR and positively associated with albuminuria. In addition, a potential pairwise interaction between Mn-Co on decreased eGFR was identified by BKMR analysis. Findings from our study suggested a positive association between exposure to the whole blood metal mixture and decreased kidney function, with blood Co, Pb, and Cd being the main contributors to this association, while Mn demonstrated an inverse relationship with renal dysfunction. However, as our study was cross-sectional in nature, further prospective studies are warranted to better understand the individual and combined effects of metals on kidney function.

Association of urinary arsenic metabolism with type 2 diabetes and glucose homeostasis: Cross-sectional and longitudinal associations

BACKGROUND

Previous researches have assessed the relationships of urinary arsenic metabolism with type 2 diabetes (T2D) and glucose-insulin homeostasis, but the results were controversial, and potential mechanisms remain largely unclear.

OBJECTIVES

This study aimed to investigate the cross-sectional and longitudinal associations of urinary arsenic metabolism with T2D prevalence and glucose changes in relatively higher arsenic exposure, and further to evaluate the underlying roles of oxidative damage in these relationships.

METHODS

We included 796 participants at baseline, among them 509 participants were followed up after 2 years. Logistic regression model and leave-one-out approach were applied to evaluate the associations of arsenic metabolism with T2D prevalence. Linear mixed model was conducted to estimate the relationship of arsenic metabolism with glycemic changes over two years. The associations between arsenic metabolism and indicators of oxidative stress were assessed with a linear regression model. We further performed mediation analysis to investigate the role of oxidative stress in the associations of arsenic metabolism with 2-year change of glucose levels.

RESULTS

Higher urinary MMA% increased T2D prevalence and baseline glucose levels. MMA% was positively associated with 2-year change of glucose levels. Moreover, we observed significant dose-response relationship between MMA% and 8-hydroxy-2-deoxyguanosine (8-OHdG). However, the mediating role of 8-OHdG in the association of MMA% and 2-year change of glucose levels was not observed in this population.

CONCLUSIONS

In this population exposure to relatively higher arsenic levels, higher MMA% contributed to increased T2D prevalence and glucose homeostasis disorder. Arsenic metabolism also affected oxidative stress levels, especially 8-OHdG. Further studies are required to investigate the potential mechanisms.

Urinary arsenic metabolism, genetic susceptibility, and their interaction on type 2 diabetes

Growing studies investigated the association of arsenic metabolism with type 2 diabetes (T2D), however, the epidemiological evidence is inconsistent. In addition, the interaction of arsenic metabolism-related genetic risk score (GRS)-arsenic on T2D risk was unclear. The present study aimed to evaluate the association of arsenic metabolism efficiency [inorganic arsenic (iAs)%, monomethylarsonic acid (MMA)%, and dimethylarsinic acid (DMA%)] with T2D risk. Moreover, the relationship of GRS and arsenic metabolism efficiency and the interaction of GRS-arsenic on T2D were investigated. Age- and sex-matched new-onset diabetes case-control study derived from the Dongfeng-Tongji cohort was conducted and 996 pairs participants were included in this study. The leave-one-out approach was used to evaluate the association of arsenic metabolism efficiency with T2D risk. The GRS and weight GRS (wGRS) were calculated based on 79 candidate SNPs. We estimated the relationship of GRS with arsenic metabolism efficiency by linear regression model. The interaction of GRS-arsenic on T2D was assessed by adding a multiplicative interaction term (GRS × arsenic) in the logistic regression models. Urinary iAs% was positively associated with T2D risk, and the OR (95% CI) was 1.06 (1.01, 1.12). MMA% and PMI were negatively associated with T2D risk, and the ORs (95% CI) were 0.87 (0.78, 0.97) and 0.64 (0.47, 0.86), respectively. Urinary DMA, As3+, and As5+ were positively associated with T2D risk. Similar relationships were found between arsenic metabolites and levels of FPG and HbA1c. Moreover, arsenic metabolism-related GRS/wGRS was positively associated with MMA% but negatively associated with DMA%. Genetic predisposition to arsenic metabolism modified the association of inorganic arsenic with T2D risk (Pinteraction = 0.033). Taken together, lower arsenic primary metabolism efficiency (higher iAs% and lower MMA%) may increase T2D risk. Genetic predisposition to arsenic metabolism was associated with arsenic metabolism efficiency, and might modify the association of inorganic arsenic with T2D risk.

Independent and combined associations of urinary metals exposure with markers of liver injury: Results from the NHANES 2013-2016

BACKGROUND

Heavy metals entering the human body could cause damage to a variety of organs. However, the combined harmful effects of exposure to various metals on liver function are not well understood. The purpose of the study was to investigate the independent and joint relationships between heavy metal exposure and liver function in adults.

METHODS

The study involved 3589 adults from the National Health and Nutrition Examination Survey. Concentrations of urinary metals, including arsenic (As), cadmium (Cd), lead (Pb), antimony (Sb), barium (Ba), thallium (Tl), tungsten (W), uranium (U), were determined in urine using inductively coupled plasma mass spectrometry. Data for liver function biomarkers included alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transaminase (GGT), and alkaline phosphatase (ALP). Survey-weighted linear regression and quantile g-computation (qgcomp) were employed to evaluate the relationship of urinary metals with the markers of liver injury.

RESULTS

Cd, U and Ba were found to have positive correlations with ALT, AST, GGT, and ALP in the survey-weighted linear regression analyses. According to the qgcomp analyses, the total metal mixture was positively correlated with ALT (percent change: 8.15; 95% CI: 3.84, 12.64), AST (percent change: 5.55; 95% CI: 2.39, 8.82), GGT (percent change: 14.30; 95% CI: 7.81, 21.18), and ALP (percent change: 5.59; 95% CI: 2.65, 8.62), and Cd, U, and Ba were the main contributors to the combined effects. Positive joint effects were observed between Cd and U on ALT, AST, GGT and ALP, and U and Ba had positive joint effects on ALT, AST and GGT.

CONCLUSION

Exposures to Cd, U, and Ba were individually associated with multiple markers of liver injury. Mixed metal exposure might be adversely correlated with markers of liver function. The findings indicated the potential harmful effect of metal exposure on liver function.

The association between urinary metals/metalloids and chronic kidney disease among general adults in Wuhan, China

The relation between exposure to single metal/metalloid and the risk of chronic kidney disease (CKD) remains unclear. We aimed to determine the single and mixed associations of 21 heavy metals/metalloids exposure and the risk of CKD. We performed a cross-sectional study that recruited 4055 participants. Multivariate logistic regression, linear regression and weighted quantile sum (WQS) regression were conducted to explore the possible effects of single and mixed metals/metalloids exposure on the risk of CKD, the risk of albuminuria and changes in the estimated glomerular filtration rate (eGFR). In single-metal models, Cu, Fe, and Zn were positively associated with increased risks of CKD (P-trend < 0.05). Compared to the lowest level, the highest quartiles of Cu (OR = 2.94; 95% CI: 1.70, 5.11; P-trend < 0.05), Fe (OR = 2.39; 95% CI: 1.42, 4.02; P-trend < 0.05), and Zn (OR = 2.35; 95% CI: 1.31, 4.24; P-trend < 0.05) were associated with an increased risk of CKD. After multi-metal adjustment, the association with the risk of CKD remained robust for Cu (P < 0.05). Weighted quantile sum regression revealed a positive association between mixed metals/metalloids and the risk of CKD, and the association was largely driven by Cu (43.7%). Specifically, the mixture of urinary metals/metalloids was positively associated with the risk of albuminuria and negatively associated with eGFR.

The correlation of urinary strontium with the risk of chronic kidney disease among the general United States population

Background

This study sought to illustrate whether urinary strontium levels were related to developing chronic kidney disease (CKD) in the United States population.

Methods

A total of 5,005 subjects were identified from the National Health and Nutrition Examination Survey 2011-2016. Survey-weighted logistic regression analysis, multivariate linear regression analysis, restricted cubic spline (RCS) plots curve and stratified analyses were undertaken to explicate the correlation between urinary strontium and CKD.

Results

With the increase of urinary strontium, the incidence rate of CKD and urinary albumin to creatinine ratio (UACR) levels gradually decreased, and estimated glomerular filtration rate (eGFR) levels gradually increased. After controlling all confounders, only urinary strontium in the fourth quartile was correlated to a lower CKD prevalence (OR: 0.59; 95% CI, 0.44-0.79) compared to the lowest quartile. Multivariate linear regression analysis showed that urinary strontium was positively correlated with eGFR but negatively with UACR. RCS curve suggested a nonlinear relationship between urinary strontium and CKD (P for non-linearity <0.001). Stratified analyses indicated no significant difference in the correlation between urinary strontium and CKD among different subgroups.

Conclusion

Urinary strontium was strongly correlated with a low risk of CKD, and this association was non-linear among the US population.

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.

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

BACKGROUND

Arsenic (As), cadmium (Cd) and copper (Cu) are hazardous for kidney function, while the effects of selenium (Se) and zinc (Zn) were unexplored for the narrow safe range of intake. Interactions exists between these multiple metal/metalloid exposures, but few studies have investigated the effects.

METHODS

A cross-sectional survey was performed among 2210 adults across twelve provinces in China between 2020 and 2021. Urinary As, Cd, Cu, Se and Zn were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Serum creatinine (Scr) and N-acetyl-beta-D glucosaminidases (urine NAG) were quantified in serum and urine, respectively. Kidney function was evaluated by the estimated glomerular filtration rate (eGFR). We employed logistic regression and Bayesian kernel machine regression (BKMR) models to explore the individual and joint effects of urinary metals/metalloids on the risk of impaired renal function (IRF) or chronic kidney disease (CKD), respectively.

RESULTS

Association was found between As (OR = 1.24, 95 % CI: 1.03, 1.48), Cd (OR = 1.65, 95 % CI: 1.35, 2.02), Cu (OR = 1.90, 95 % CI: 1.59, 2.29), Se (OR = 1.51, 95 % CI: 1.24, 1.85) and Zn (OR = 1.33, 95 % CI: 1.09, 1.64) and the risk of CKD. Moreover, we observed association between As (OR = 1.18, 95 % CI: 1.07, 1.29), Cu (OR = 1.14, 95 % CI: 1.04, 1.25), Se (OR = 1.15, 95 % CI: 1.06, 1.26) and Zn (OR = 1.12, 95 % CI: 1.02, 1.22) and the risk of IRF. Additionally, it was found that Se exposure may strength the association of urinary As, Cd and Cu with IRF. Furthermore, it is worth noting that Se and Cu contributed greatest to the inverse association in IRF and CKD, respectively.

CONCLUSION

Our findings suggested that metal/metalloid mixtures were associated with kidney dysfunction, Se and Cu were inverse factors. Additionally, interactions between them may affect the association. Further studies are needed to assess the potential risks for metal/metalloid exposures.

Urinary Copper Excretion Is Associated with Long-Term Graft Failure in Kidney Transplant Recipients

INTRODUCTION

In chronic kidney disease, proteinuria increases urinary copper excretion, inducing oxidative tubular damage and worsening kidney function. We investigated whether this phenomenon occurred in kidney transplant recipients (KTRs). In addition, we studied the associations of urinary copper excretion with the biomarker of oxidative tubular damage urinary liver-type fatty-acid binding protein (u-LFABP) and death-censored graft failure.

METHODS

This prospective cohort study was performed in the Netherlands between 2008 and 2017, including outpatient KTR with a functioning graft for longer than 1 year, who were extensively phenotyped at baseline. Twenty-four-hour urinary copper excretion was measured by inductively coupled plasma mass spectrometry. Multivariable linear and Cox regression analyses were performed.

RESULTS

In 693 KTR (57% men, 53 ± 13 years, estimated glomerular filtration rate [eGFR] 52 ± 20 mL/min/1.73 m2), baseline median urinary copper excretion was 23.6 (interquartile range 11.3-15.9) µg/24 h. Urinary protein excretion was positively associated with urinary copper excretion (standardized β = 0.39, p < 0.001), and urinary copper excretion was positively associated with u-LFABP (standardized β = 0.29, p < 0.001). During a median follow-up of 8 years, 109 (16%) KTR developed graft failure. KTR with relatively high copper excretion were at higher risk of long-term graft failure (hazard ratio [HR]: 1.57, 95% confidence interval [CI]: 1.32-1.86 per log2, p < 0.001), independent of multiple potential confounders like eGFR, urinary protein excretion, and time after transplantation. A dose-response relationship was observed over increasing tertiles of copper excretion (HR: 5.03, 95% CI: 2.75-9.19, tertile 3 vs. 1, p < 0.001). u-LFABP was a significant mediator of this association (74% of indirect effect, p < 0.001).

CONCLUSION

In KTR, urinary protein excretion is positively correlated with urinary copper excretion. In turn, higher urinary copper excretion is associated with an independent increased risk of kidney graft failure, with a substantial mediating effect through oxidative tubular damage. Further studies are warranted to investigate whether copper excretion-targeted interventions could improve kidney graft survival.

Association between urinary metal concentrations and abnormal estimated glomerular filtration rate in Chinese community-dwelling elderly: Exploring the mediating effect of triglycerides

BACKGROUND

Environmental metal exposure is associated with elevated triglycerides (TG) and the development of chronic kidney disease (CKD). However, the relationship between metal exposure and glomerular filtration rate (GFR) remains uncertain, and the mediating effect of TG between the two is unclear.

METHODS

This study measured the concentrations of 14 metals in urine samples from 3752 elderly people in the community. The most relevant metals were screened by least absolute shrinkage and selection operator (LASSO) regression. The relationship between combined exposure to multiple metals and abnormal estimated glomerular filtration rate (eGFR) was explored using multivariate logistic regression analysis and Bayesian kernel machine regression (BKMR) analysis. Generalized linear regression models and the Karlson-Holm-Green (KHB) method were used to assess the mediating effects of TG.

RESULTS

In the single-metal model, calcium (Ca), iron (Fe), selenium (Se), strontium (Sr), and thallium (Tl) showed significant negative correlations with the prevalence of abnormal eGFR (all P < 0.05). In the multi-metals model, Ca, Se, and Tl continued to show significant negative correlations, while vanadium (V) and zinc (Zn) showed significant positive correlations with abnormal eGFR (all P < 0.05). The BKMR model showed a negative joint effect of the mixture of Ca, V, Zn, Se, and Tl on the prevalence of abnormal eGFR. The generalized linear regression model showed a significant positive correlation between the concentrations of Ca (β = 0.07), Zn (β = 0.07), Se (β = 0.09), and TG levels (all P < 0.05). In the mediation analysis, TG masked a 4.30% and 5.21% correlation between Ca and Se and the prevalence of eGFR abnormalities, respectively.

CONCLUSIONS

Urinary concentration of multiple metals is significantly associated with eGFR abnormalities, and Ca, and Se may be among the potential protective factors. TG masked some of the protective effects of Ca and Se.

Association of urine phthalate metabolites levels with kidney function in 1610 US adolescents

Phthalates are widely used as plasticizer or fragrance ingredients in various consumer products worldwide. However, evidence for the overall effects of mixed exposure to phthalate on kidney function has not been widely investigated. The purpose of this article was to assess the association of urine phthalate metabolite levels and kidney injury parameters in adolescents. We used data from the combined 2007-2016 National Health and Nutrition Examination Survey (NHANES). We fitted weighted linear regressions and Bayesian kernel machine regressions (BKMR) models to explore the association of urinary phthalate metabolites with four parameters of kidney function after adjusting for covariates. Weighted linear regression models showed that MiBP (β = 8.057; P_FDR = 0.016) was significantly positively associated with eGFR and MEP (β = -0.799; P_FDR < 0.001) was significantly negatively correlated with BUN. BKMR analysis showed that the higher the concentration of phthalate metabolite mixture, the higher eGFR in adolescents. Based on the results of these two models, our findings revealed that mixed exposure to phthalates was associated with elevated eGFR in adolescents. However, as the study is cross-sectional, reverse causality is possible, and altered kidney function may impact the concentration of phthalate metabolites in urine.

Microcystins Exposure Associated with Blood Lipid Profiles and Dyslipidemia: A Cross-Sectional Study in Hunan Province, China

Increasing evidence from experimental research suggests that exposure to microcystins (MCs) may induce lipid metabolism disorder. However, population-based epidemiological studies of the association between MCs exposure and the risk of dyslipidemia are lacking. Therefore, we conducted a population-based cross-sectional study involving 720 participants in Hunan Province, China, and evaluated the effects of MCs on blood lipids. After adjusting the lipid related metals, we used binary logistic regression and multiple linear regression models to examine the associations among serum MCs concentration, the risk of dyslipidemia and blood lipids (triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)). Moreover, the additive model was used to explore the interaction effects on dyslipidemia between MCs and metals. Compared to the lowest quartile of MCs exposure, the risk of dyslipidemia [odds ratios (OR) = 2.27, 95% confidence interval (CI): 1.46, 3.53] and hyperTG (OR = 3.01, 95% CI: 1.79, 5.05) in the highest quartile was significantly increased, and showed dose-response relationships. MCs were positively associated with TG level (percent change, 9.43%; 95% CI: 3.53%, 15.67%) and negatively associated with HDL-C level (percent change, -3.53%; 95% CI: -5.70%, -2.10%). In addition, an additive antagonistic effect of MCs and Zn on dyslipidemia was also reported [relative excess risk due to interaction (RERI) = -1.81 (95% CI: -3.56, -0.05)], and the attributable proportion of the reduced risk of dyslipidemia due to the antagonism of these two exposures was 83% (95% CI: -1.66, -0.005). Our study first indicated that MCs exposure is an independent risk factor for dyslipidemia in a dose-response manner.

Evaluation of School-Age Children's Intelligence Quotient and Their Chronic Exposure to Trace Elements in Ambient Air

Background Children's exposure to different trace elements in their air, water, and food or even present in paints or toys can affect their intelligence quotient (IQ) score. However, this correlation needs to be analyzed and evaluated in different contexts. This study aimed to investigate the associations between airborne concentrations of lead (Pb), manganese (Mn), cadmium (Cd), chromium (Cr), and arsenic (As) and intellectual function in school-age children in Makkah, Kingdom of Saudi Arabia. Methodology Our cohort study aimed to explore the link between exposure to various trace elements in the surrounding air and the IQ scores of children residing in the vicinity of Makkah. We included 430 children in the study and collected information about demographic and lifestyle factors using a structured questionnaire. We employed a mini volume sampler (MiniVol, AirMetrics, Springfield, OR, USA) to collect 24-hour PM10 samples from five locations in Makkah, representing various residential areas with small-to-medium industrial activities and traffic load. We analyzed the samples for Pb, Mn, Cd, Cr, and As concentrations using inductively coupled plasma-mass spectrometry with Perkin Elmer 7300 (Perkin Elmer, Waltham, MA, USA). The combined impact of heavy metals on continuous outcomes was assessed using the Bayesian kernel machine regression model. Results The mean atmospheric concentrations of Pb, Mn, Cd, Cr, and As in summer were 0.093, 0.006, 0.36, 0.15, and 0.017 µg/m³, respectively, while in winter, they were 0.004, 0.003, 0.12, 0.006, and 0.01 µg/m³, respectively. The findings of our study revealed that children's IQ scores were independently associated with co-exposure to the five metals, namely, Pb, Mn, Cd, Cr, and As. Conclusions This study demonstrates a link between combined exposure to five heavy metals (Pb, Mn, Cd, Cr, and As) and children's IQ scores. Regularly evaluating trace elements in children's biological samples is crucial to comprehend their effects on cognitive growth. To explore the possible future health risks of multimetal exposures and their interaction effects, it is imperative to conduct additional studies that involve repeated biological measurements of metal concentrations.

Coexposure to multiple metals and renal tubular damage: a population-based cross-sectional study in China's rural regions

Previous studies have indicated that exposure to a single toxic metal can cause renal tubular damage, while evidence about the effects of multimetal exposure on renal tubular damage is relatively limited. We aimed to evaluate the relationships of multimetal coexposure with renal tubular damage in adults in heavy metal-polluted rural regions of China. A cross-sectional study of 1918 adults in China's heavy metal-contaminated rural regions was conducted. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure the plasma levels of 18 metals in participants, and immune turbidimetry was used to measure sensitive biological indicators, reflecting renal tubular damage (including retinol-binding protein and β2-microglobulin). Least absolute shrinkage and selection operator (LASSO) penalized regression analysis, logistic and linear regression analysis, restricted cubic spline (RCS) regression analysis and the Bayesian kernel machine regression (BKMR) method were used to explore associations of multimetal coexposure with renal tubular damage risk or renal tubular damage indicators. Plasma selenium, cadmium, arsenic, and iron were identified as the main plasma metals associated with renal tubular damage risk after dimensionality reduction. Multimetal regression models showed that selenium was positively associated, and iron was negatively associated with renal tubular damage risk or its biological indicators. Multimetal RCS analyses additionally revealed a non-linear relationship of selenium with renal tubular damage risk. The BKMR models showed that the metal mixtures were positively associated with biological indicators of renal tubular damage when the metal mixtures were above the 50th percentile of concentration. Our findings indicated that natural exposure to high levels of multimetal mixtures increases the risk of renal tubular damage. Under the conditions of multimetal exposure, selenium was positively associated, and iron was negatively associated with renal tubular damage risk or its biological indicators.

Combined Exposure to Multiple Metals and Kidney Function in a Midlife and Elderly Population in China: A Prospective Cohort Study

[Background] Metal exposure is suspected to be correlated to kidney function. However, the combined effects of co-exposing to multiple metals, especially both toxic and protective metals, have not been completely evaluated. [Method] A prospective cohort study was conducted with the "135" cohort for the evaluation of how plasma metal levels are correlated to kidney function in a midlife and elderly community in southern China. An amount of 1368 subjects without kidney disease at baseline were enrolled in the final analysis. By using linear regression and logistic regression models, the correlation of individual metal values with renal function parameters was assessed. Measuring of the multiple metal exposure level was performed by principal component analysis (PCA). [Results] Diminished renal function, as evaluated based on fast kidney function decline, or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m², was positively associated with the plasma concentrations of chromium and potassium, but it was negatively associated with selenium and iron (p < 0.05). In multiple-metal analyses, linear and logistic regression models showed that the iron and chromium exposure pattern had a protective effect on renal function, whereas the sodium and potassium exposure pattern and the cadmium and lead exposure pattern increased the risk for fast kidney function decline, and eGFR < 60 mL/min/1.73 m². [Conclusions] Certain metals, including chromium, potassium, selenium, and iron, were correlated with kidney function in a midlife and elderly community in China. In addition, the potential combined influences of co-exposing to multiple metals were observed.

Insights into the health status of the general population living near an electroplating industry zone: metal elevations and renal impairment

A cross-sectional study was conducted in 2016 in Zhejiang Province, China, to evaluate the body burdens of metals and metalloids associated with renal dysfunction in populations living near electroplating industries. We recruited 236 subjects and performed physical examinations, determined the blood and urinary levels of arsenic (As), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), and selenium (Se) by an inductively coupled plasma mass spectrometer (ICP-MS), and measured three renal impairment biomarkers, namely nacetyl-β-_D-glucosaminidase (NAG), retinol-binding protein (RBP), and β₂-microglobulin (BMG). The proportion of abnormal nasal symptoms in the exposure group (10.1%) was much higher than in the control group (0; p < 0.05). The blood and urinary levels of As, Cd, and Se in the exposure group were significantly higher than those in the control group (p < 0.05). The blood levels of Mn and Pb, as well as the urinary levels of Cr and Ni, were significantly higher in the exposure group than in the control group (p < 0.05). The exposure group demonstrated higher levels of NAG, RBP, and BMG than the control group (0.51 vs. 0.14 mg/g creatinine, 12.79 vs. 9.26 IU/g creatinine, and 1.39 vs. 0.78 mg/g creatinine, respectively; p < 0.05). Urinary BMG was positively correlated with urinary Cd levels (r = 0.223, p < 0.05), while urinary RBP was correlated with blood Cd levels (r = 0.151, p < 0.05) and urinary Cd, Cr, Ni, and Se levels (r = 0.220, 0.303, 0.162, and 0.306, respectively; p < 0.05). In conclusion, our study indicated that a population living in the vicinity of electroplating industries had high body burdens of certain metals and metalloids associated with non-negligible renal dysfunction.

Joint effects of per- and polyfluoroalkyl substance alternatives and heavy metals on renal health: A community-based population study in China

BACKGROUND

Previous studies have indicated that chlorinated polyfluorinated ether sulfonic acids (Cl-PFESAs), when used as an alternative to per- and polyfluoroalkyl substances (PFASs), result in kidney toxicity. However, their co-exposure with heavy metals, has not yet been described.

OBJECTIVES

To explore the joint effects of Cl-PFESAs and heavy metal exposure on renal health in Chinese adults, and identify specific pollutants driving the associations.

METHODS

Our sample consists of 1312 adults from a cross-sectional survey of general communities in Guangzhou, China. We measured Cl-PFESAs, legacy PFASs (perfluorooctanoic acid [PFOA] and perfluorooctane sulfonated [PFOS]), and heavy metals (arsenic, cadmium, and lead). The relationship between single pollutant and glomerular filtration rate (eGFR) and the odds ratio (OR) of chronic kidney disease (CKD) was studied using Generalized additive models (GAMs). Bayesian Kernel Machine Regression (BKMR) models were applied to assess joint effects of Cl-PFESAs and heavy metals. Additionally, we conducted a sex-specific analysis to determine the modification effect of this variable.

RESULTS

In single pollutant models, CI-PFESAs, PFOA, PFOS and arsenic were negatively associated with eGFR. Additionally, PFOA and heavy metals were positively correlated with the OR of CKD. For example, the estimated change with 95% confidence intervals (CI) of eGFR at from the highest quantile of 6:2 Cl-PFESA versus the lowest quantile was -5.65 ng/mL (95% CI: -8.21, -3.10). Sex played a role in modifying the association between 8:2 Cl-PFESA, PFOS and eGFR. In BKMR models, pollutant mixtures had a negative joint association with eGFR and a positive joint effect on CKD, especially in women. Arsenic appeared to be the primary contributing pollutant.

CONCLUSION

We provide epidemiological evidence that Cl-PFESAs independently and jointly with heavy metals impaired kidney health. More population-based human and animal studies are needed to confirm our results.

Copper Induces Cognitive Impairment in Mice via Modulation of Cuproptosis and CREB Signaling

It has been reported that disordered Cu metabolism is associated with several neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). However, the underlying mechanism is still unclear. In this study, 4-week-old male mice were exposed to Cu by free-drinking water for three months. Then, the effects of Cu on cognitive functions in mice were tested by Morris water maze tests, and the potential mechanisms were investigated by the ELISA, immunochemistry, TUNEL, and Western blot tests. It was found that Cu exacerbates learning and memory impairment, and leads to Cu-overload in the brain and urine of mice. The results showed that Cu induces neuronal degeneration and oxidative damage, promotes the expression of apoptosis-related protein Bax, cuproptosis-related proteins FDX1 and DLAT and the proteotoxic stress marker HSP70, and decreases Fe-S cluster proteins. In addition, Cu affects the pre-synaptic and post-synaptic regulatory mechanisms through inhibiting the expression of PSD-95 and SYP. Cu also suppresses phosphorylation levels in CREB and decreases the expression of BDNF and TrkB in the mouse hippocampus. In conclusion, Cu might mediate cuproptosis, damage synaptic plasticity and inhibit the CREB/BDNF pathway to cause cognitive dysfunction in mice.

Combination Effect of Microcystins and Arsenic Exposures on CKD: A Case-Control Study in China

Evidence has shown that exposure to environmental pollutants such as microcystins (MCs), arsenic (As), and cadmium (Cd) can lead to the occurrence and development of chronic kidney disease (CKD). There is a synergistic effect between MCs and Cd. However, the combined effect of MCs and As exposures on CKD remains unclear. In Hunan province, China, 135 controls and 135 CKD cases were enrolled in a case-control study. Serum MCs, plasma As and Cd concentrations were measured for all participants. We investigated the association between MCs/As and CKD risk using conditional logistic regression. The additive model explored the interaction effect, and the Bayesian kernel machine regression (BKMR) models investigated the combined effects of MCs, As, and Cd on CKD. The results showed that MCs and As were significantly associated with CKD risk. Participants in the highest MCs concentration had a 4,81-fold increased risk of CKD compared to those in the lowest quartile (95% confidence interval [CI]: 1,96 to 11,81). The highest quartile of As concentrations corresponded to an adjusted odds ratio of 3.40 (95% CI: 1.51, 7.65) relative to the lowest quartile. MCs/As and CKD risk exhibited significant dose-response correlations (all p for trend < 0.01). In addition, a positive interaction effect of MCs and As on CKD was also reported. The CKD risk due to interaction was 2.34 times (95% CI: 0.14, 4.54) relative to the CKD risk without interaction, and the attributable proportion of CKD due to interaction among individuals with both exposures was 56% (95% CI: 0.22, 0.91). In the BKMR, the combined effect of MCs, As, and Cd was positively associated with CKD. In conclusion, both MCs and As are independent risk factors for CKD, exerting a synergistic effect between them. Combined exposure to MCs, As, and Cd can increase the risk of CKD.

Association of single and joint metals with albuminuria and estimated glomerular filtration longitudinal change in middle-aged adults from Spain: The Aragon workers health study

The nephrotoxicity of low-chronic metal exposures is unclear, especially considering several metals simultaneously. We assessed the individual and joint association of metals with longitudinal change in renal endpoints in Aragon Workers Health Study participants with available measures of essential (cobalt [Co], copper [Cu], molybdenum [Mo] and zinc [Zn]) and non-essential (As, barium [Ba], Cd, chromium [Cr], antimony [Sb], titanium [Ti], uranium [U], vanadium [V] and tungsten [W]) urine metals and albumin-to-creatinine ratio (ACR) (N = 707) and estimated glomerular filtration rate (eGFR) (N = 1493) change. Median levels were 0.24, 7.0, 18.6, 295, 3.1, 1.9, 0.28, 1.16, 9.7, 0.66, 0.22 μg/g for Co, Cu, Mo, Zn, As, Ba, Cd, Cr, Sb, Ti, V and W, respectively, and 52.5 and 27.2 ng/g for Sb and U, respectively. In single metal analysis, higher As, Cr and W concentrations were associated with increasing ACR annual change. Higher Zn, As and Cr concentrations were associated with decreasing eGFR annual change. The shape of the longitudinal dose-responses, however, was compatible with a nephrotoxic role for all metals, both in ACR and eGFR models. In joint metal analysis, both higher mixtures of Cu-Zn-As-Ba-Ti-U-V-W and Co-Cd-Cr-Sb-V-W showed associations with increasing ACR and decreasing eGFR annual change. As and Cr were main drivers of the ACR change joint metal association. For the eGFR change joint metal association, while Zn and Cr were main drivers, other metals also contributed substantially. We identified potential interactions for As, Zn and W by other metals with ACR change, but not with eGFR change. Our findings support that Zn, As, Cr and W and suggestively other metals, are nephrotoxic at relatively low exposure levels. Metal exposure reduction and mitigation interventions may improve prevention and decrease the burden of renal disease in the population.

Associations between co-exposure to multiple metals and renal function: a cross-sectional study in Guangxi, China

The association between co-exposure to multiple metals and renal function is poorly understood. We aimed to evaluate the individual and joint effects of metal exposure on renal function in this study. We performed a cross-sectional study including 5828 participants in Guangxi, China, in 2019. Urine concentrations of 17 metals were detected by inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression model and restricted cubic spline (RCS) were applied to investigate the association of individual metal exposure with renal dysfunction. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the co-exposure effects of the metals. Participants with the highest quartile of urinary Cu were at 1.84-fold (95% confidence interval (CI): 1.20-2.87) increased risk of renal dysfunction compared with the lowest quartile. The highest quartiles of urinary Sr, Cs, V, Ba, and Se were associated with 0.27-fold (95% CI: 0.17-0.43), 0.33 (95% CI: 0.19-0.53), 0.41 (95% CI: 0.25-0.65), 0.58 (95% CI: 0.36-0.90), and 0.33 (95% CI: 0.19-0.56) decreased risk of renal dysfunction compared with their lowest quartile, respectively. Furthermore, urinary Ba and Cu were non-linearly correlated with renal dysfunction. The WQS analysis showed that mixed metal exposure was inversely associated with renal dysfunction (OR = 0.47, 95% CI: 0.35-0.62), and Sr accounted for the largest weight (52.2%), followed by Cs (32.3%) in the association. Moreover, we observed a potential interaction between Cu, Cs, and Ba for renal dysfunction in BKMR model. Exposure to Se, Sr, Cs, V, and Ba is associated with decreased risk of renal dysfunction, whereas an increased risk is associated with Cu exposure. Co-exposure to these metals is negatively associated with renal dysfunction, and Sr and Cs are the main contributors to the associations.

Potential Role of Copper in Diabetes and Diabetic Kidney Disease

Copper is a fundamental element for the homeostasis of the body. It is the third most abundant essential transition metal in humans. Changes in the concentration of copper in the blood are responsible for numerous diseases affecting various organs, including the heart, brain, kidneys, and liver. Even small copper deficiencies can lead to the development and progression of several pathologies. On the other hand, excessive exposure to copper can cause toxicity in many human organs, leading to various systemic alterations. In the kidney, increased copper concentration in the blood can cause deposition of this element in the kidneys, leading to nephrotoxicity. One of the most interesting aspects of copper balance is its influence on diabetes and the progression of its complications, such as Diabetic Kidney Disease (DKD). Several studies have shown a close relationship between copper serum levels and altered glycemic control. An imbalance of copper can lead to the progression of diabetes-related complications and impaired antioxidant homeostasis. A high Zinc/Copper (Zn/Cu) ratio is associated with improved renal function and reduced risk of poor glycemic control in patients with type two diabetes mellitus (T2DM). Furthermore, the progression of DKD appears to be related to the extent of urinary copper excretion, while regulation of adequate serum copper concentration appears to prevent and treat DKD. The aim of this review is to evaluate the possible role of copper in DKD patients.

Association of low cadmium and mercury exposure with chronic kidney disease among Chinese adults aged ≥80 years: A cross-sectional study

BACKGROUND

The heavy metals cadmium (Cd) and mercury (Hg) are known to be widespread environmental contaminants and high occupational exposure adversely affects the risk of chronic kidney disease (CKD). However, evidence from epidemiological studies linking low Cd and Hg exposure (or non-industrial) to the risk of progression to CKD are conflicting. This study aimed to explore the association of low Cd and Hg exposure with the risk of CKD in Chinese adults aged ≥80 years.

METHODS

The participants were recruited for the Healthy Aging and Biomarkers Cohort Study in 2017, an ongoing perspective survey conducted in longevity areas in China initially involving 3016 older adults. We used logistic regression models to estimate odds ratios (ORs) with 95% confidence intervals of CKD setting Cd and Hg as categorical variables. Logistic regression with restricted cubic spline was used to characterize a dose-response relationships between Cd or Hg concentrations and the risk of CKD in the study population.

RESULTS

The ORs for the risk of CKD comparing the fourth to the first quartile of blood Cd, blood Hg, urine Cd, and urine Hg were 1.77, 1.57, 2.03, and 1.50, respectively. Restricted cubic spline models showed that blood Cd and urine Hg were significantly linearly correlated with the risk of CKD, while blood Hg and urine Cd were non-linearly correlated with the risk of CKD with a steeper slope at concentrations <2.30 μg/L and 3.30 μg/g creatinine.

CONCLUSIONS

Our findings suggest that even low Cd and Hg exposure (or non-industrial) were associated with increased risk of CKD in Chinese oldest old, although we did not find a significant multiplicative and additive interaction between Cd and Hg levels in relation to the risk of CKD.

Relationship of serum copper and zinc with kidney function and urinary albumin to creatinine ratio: Cross-sectional data from the NHANES 2011-2016

BACKGROUND & OBJECTIVE

Chronic kidney disease (CKD) is a common condition in worldwide with underlying causes. The role of trace elements such as copper and zinc in CKD is uncertain. We aimed to examine the relationship of serum copper and zinc with kidney function status and explore its possible effect modifiers in the general population.

METHODS

Data from 5353 National Health and Nutrition Examination Survey (NHANES) participants from 2011 to 2016 were analyzed for the role of trace elements in the age range 18 to 80 years. The kidney outcomes were reduced estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and increased urinary albumin-to-creatinine ratio (ACR) ≥ 30 mg/g.

RESULTS

Findings showed a significant positive association between serum copper and urinary ACR (OR = 1.04, 95% CI = 1.00-1.07). Serum copper levels of 18.0 μmol/L (median) or higher (reference level <18.0 μmol/L) were significantly associated with increased urinary ACR (OR = 1.67, 95% CI = 1.21-2.31) after adjusting for confounding factors. In contrast, there was a significant inverse association between serum zinc and reduced eGFR (OR = 0.89,95% CI = 0.81-0.99). Where serum zinc level was greater than 12.3 μmol/L (median), the prevalence of reduced eGFR was lower (OR = 0.65, 95% CI = 0.16-0.60). In addition, a stratified analysis based on various risk factors found that in those individuals with serum albumin greater than 43 g/L or systolic blood pressure greater than 120 mmHg, positive correlations between serum copper and risk of increased urinary ACR was more significant.

CONCLUSIONS

Our findings suggest that the reference levels of serum copper and zinc levels in healthy individuals may be different from current understanding. If further studies substantiate the same, the results will be a useful guide for designing future clinical trials and nutritional guidelines.

Associations between plasma metal levels and mild renal impairment in the general population of Southern China

BACKGROUND

Metal exposure were assumed to be closely related with declined renal function, but the conclusions were controversial. We employed diverse statistical models and assessed the association between metal mixture exposure and mild renal impairment.

METHODS

A total of 13 plasma metals were measured in 896 general population from Southern China. Subjects with estimated glomerular filtration rate within 60-89 ml/min/1.73 m² and urinary albumin-creatinine ratio <30 mg/g creatinine were defined as mild renal impairment (MRI).

RESULTS

About 31.47 % participants showed MRI. In the multivariate logistic regression models, compared with the first quartile, high levels of arsenic and molybdenum (the fourth quartile) were both associated with MRI, and the ORs (95 % CI) were 1.68 (1.05, 2.68) and 2.21 (1.40, 3.48), respectively. Their predominant roles were identified by the weighted quantile regression (WQS). Besides, restricted cubic spline analysis verified the relationship between molybdenum level and increased MRI risk in a linear and dose-response manner.

CONCLUSION

High levels of arsenic and molybdenum might be independent risk factors of MRI, and they showed combined effect. Our findings might provide vigorous evidence in preventing mild decline in renal function.

Association of copper exposure with prevalence of chronic kidney disease in older adults

BACKGROUND & AIMS

Metal exposure is suspected to be associated with the risk of chronic kidney disease (CKD). Copper (Cu) is an essential yet toxic trace element in humans. Epidemiological evidence on the association of Cu exposure with CKD remains inconsistent. This study aims to investigate the association of blood Cu and its co-exposure to other metals with CKD.

METHODS

A cross-sectional study was conducted among 3285 older participants in Zhejiang, China. The whole blood levels of Cu as well as other 10 metals were measured using the inductively coupled plasma mass spectrometry (ICP-MS). CKD events were defined as the presence of albuminuria or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m². Multivariable logistic regression and linear regression models were applied to assess the association of Cu with kidney function. The Bayesian kernel machine regression (BKMR) was used to examine the association of metal interactions with CKD.

RESULTS

In logistic models, we found a dose-dependent positive association between blood Cu and the prevalence of CKD. Compared to the lowest quartile of blood Cu, the odds ratio (OR) of CKD in the highest quartile was 1.65 (95% confidence interval, CI: 1.25, 2.17), and the β of eGFR was -1.74 (95% CI: -3.15, -0.34) after adjusting for multiple covariates. The positive linear dose-response association was found between blood Cu and the OR of CKD, and negative linear association was found between Cu and the β of eGFR. The positive association between blood Cu and CKD risk was stronger at lower level of manganese (Mn) in the BKMR model.

CONCLUSION

The whole blood level of Cu was remarkably associated with the risk of CKD and showed positive dose-response relationships in the older Chinese population. The toxicity of Cu on kidney function could be antagonized by the exposure of Mn. These findings shed new light on the potential role of Cu in kidney health.

Toxic Metals in Particulate Matter and Health Risks in an E-Waste Dismantling Park and Its Surrounding Areas: Analysis of Three PM Size Groups

Heavy metals generated from e-waste have created serious health risks for residents in e-waste disposal areas. This study assessed how airborne toxic metals from an e-waste dismantling park (EP) influenced surrounding residential areas after e-waste control. PM_2.5, PM₁₀, and total suspended particles (TSP) were sampled from 20 sites, including an EP, residential areas, and an urban site; ten kinds of metals were analyzed using ICP-MS and classified as PM_2.5, PM_2.5-10, and PM_10-100. Results showed that metals at the EP tended to be in coarser particles, while metals from residential areas tended to be in finer particles. A source analysis showed that metals from the EP and residential areas may have different sources. Workers' cancer and non-cancer risks were higher when exposed to PM_2.5-10 metals, while residents' risks were higher when exposed to PM_2.5 metals. As and Cr were the most strongly associated with cancer risks, while Mn was the most strongly associated with the non-cancer risk. Both workers and residents had cancer risks (>1.0 × 10^-6), but risks were lower for residents. Therefore, e-waste control can positively affect public health in this area. This study provides a basis for further controlling heavy metal emissions into the atmosphere by e-waste dismantling and encouraging worldwide standardization of e-waste dismantling.

Microcystin-LR Combined with Cadmium Exposures and the Risk of Chronic Kidney Disease: A Case-Control Study in Central China

Increasing evidence indicates that exposure to microcystin-LR (MC-LR) can cause kidney damage. However, the association between MC-LR exposure and chronic kidney disease (CKD) risk in humans has not been studied. Therefore, we conducted a population-based case-control study involving 135 CKD cases and 135 matched controls in central China and analyzed the effects of MC-LR alone as well as combined with the known risk factor cadmium (Cd). Compared to the lowest quartile of MC-LR exposure, the highest quartile had a 6.56-fold (95% confidence interval [CI]: 2.46, 17.51) significantly increased risk for CKD, displaying a dose-response relationship (p_trend < 0.001). Our animal study also showed that MC-LR exposure induced kidney injury via the PI3K/AKT/mTOR signaling pathway. Comparing the highest Cd quartile to the lowest, the adjusted odds ratio for CKD was 3.88 (95% CI: 1.47, 10.28), exhibiting a dose-response relationship (p_trend < 0.006). Furthermore, a positive additive interaction was observed between MC-LR and Cd (relative excess risk due to interaction = 1.81, 95% CI: 0.42, 3.20; attributable proportion of interaction = 0.70, 95% CI: 0.35, 1.05). Our study firstly revealed that MC-LR exposure is an independent risk factor for CKD and has a synergistic relationship with Cd. MC-LR and Cd exposures are associated with CKD risk in a dose-response manner.

Sex-Based Differences in the Association between Serum Copper and Kidney Function: Evidence from NHANES 2011-2016

Epidemiological evidence on the relationship between copper (Cu) and kidney function is rare, and few studies examine the sex differences in this association. We aimed to explore the overall and sex-based relationship between exposure to Cu and biomarkers of kidney function among 4331 participants of the 2011-2016 National Health and Nutrition Examination Survey. Multiple linear regression models were fitted to examine the overall and sex-specific associations between serum Cu and the kidney function indicator-estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (UACR). Restricted cubic spline models (RCS) stratified by sex were performed to explore the sex-based dose-response associations. Serum Cu in the highest quartile was associated with higher levels of UACR (β = 0.203, 95% CI: 0.100 to 0.306) among overall participants. In males, there was an association of the highest Cu quartile with decreased eGFR (β = -0.023, 95% CI: -0.042 to -0.003) and increased UACR (β = 0.349, 95% CI: 0.171 to 0.527); serum Cu levels also demonstrated a negative nonlinear dose-response association with eGFR and a positive linear dose-response association with UACR in males, whereas females showed a marginally significant nonlinear positive association of eGFR with serum Cu levels. In conclusion, there were sex-specific and dose-response relationships between serum Cu and kidney function indicators. Further prospective and mechanistic studies are warranted.

Association of Urinary Strontium with Cardiovascular Disease Among the US Adults: A Cross-Sectional Analysis of the National Health and Nutrition Examination Survey

Previous studies have demonstrated the effects of environmental metals on the cardiovascular system. However, the relationship of strontium (Sr) to cardiovascular disease (CVD) in the general population has not been established. This cross-sectional study aimed to investigate the association between urinary Sr (U-Sr) and CVD in the US adults using data of 5255 participants from the National Health and Nutrition Examination Survey (NHANES) 2011-2016. Multivariable logistic regression and restricted cubic spline (RCS) regression were performed to assess the association between U-Sr and CVD. After multivariable adjustments, compared to the lowest quartile, the adjusted odds ratios (ORs) of CVD with 95% confidence intervals (CIs) across the quartiles were 0.65 (0.46, 0.92), 0.87 (0.61, 1.25), and 0.78 (0.55, 1.10). RCS plot revealed a nonlinear relationship between U-Sr levels and CVD (P for nonlinearity = 0.004). Threshold effect analysis identified the inflection point of U-Sr for the curve was 90.18 μg/g urinary creatinine (μg/g UCr). Each 1-unit increase in U-Sr was associated with a 1.1% decrease in CVD (OR 0.989; 95% CI 0.980-0.998) on the left side of the inflection point, but no significant association was observed on the right side of the inflection point. This study suggests a nonlinear association of U-Sr with CVD prevalence in the US general adults. These findings may have positive implications for the determination of appropriate Sr levels for public cardiovascular health. Given the cross-sectional study design, further prospective studies are warranted.

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.

Co-exposure to perfluoroalkyl acids and heavy metals mixtures associated with impaired kidney function in adults: A community-based population study in China

BACKGROUND

Previous studies have separately linked either perfluoroalkyl acid (PFAA) or heavy metal exposure with kidney dysfunction. However, the relationships of co-exposure to PFAAs and heavy metals with kidney function are still unclear.

OBJECTIVES

To explore the associations between exposure to PFAAs and heavy metals mixtures and kidney function in adults.

METHODS

We conducted a cross-sectional community-based population study in Guangzhou, China, enrolling 1312 adults from November 2018 to August 2019. We quantified 13 PFAAs in serum and 14 heavy metals in plasma. We chose estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) as outcomes of interest. Distributed lag non-linear models (DLNMs) were used to check nonlinearity of individual pollutant with kidney function. Joint associations of pollutant mixtures on kidney function were assessed by Bayesian Kernel Machine Regression (BKMR) models. We further explored modification effects of gender.

RESULTS

Most individual PFAA and heavy metal were associated with declined kidney function in single-pollutant models. We also observed significant dose-response relationships of pollutant mixtures with reduced eGFR levels and increased odds of CKD in BKMR models. Perfluoroheptanesulfonic acid (PFHpS), arsenic (As) and strontium (Sr) were the predominant contributors among pollutant mixtures. A change in log PFHpS, As and Sr concentrations from the 25th to the 75th percentile were associated with a decrease in eGFR of -5.42 (95% confidence interval (CI): -6.86, -3.98), -2.14 (95% CI: -3.70, -0.58) and -1.87 (95% CI: -3.03, -0.72) mL/min/1.73 m², respectively, when other pollutants were at their median values. In addition, the observed associations were more obvious in females.

CONCLUSIONS

We provided new evidence that co-exposure to PFAAs and heavy metals mixtures was associated with reduced kidney function in adults and PFHpS, As and Sr appeared to be the major contributors. Further studies are warranted to confirm our findings and elucidate the underlying mechanisms.

Metal(loid)s in Common Medicinal Plants in a Uranium Mining-Impacted Area in Northwestern New Mexico, USA

The objective of this study was to determine uranium (U) and other metal(loid) concentrations (As, Cd, Cs, Pb, Mo, Se, Th, and V) in eight species of plants that are commonly used for medicinal purposes on Diné (Navajo) lands in northwestern New Mexico. The study setting was a prime target for U mining, where more than 500 unreclaimed abandoned U mines and structures remain. The plants were located within 3.2 km of abandoned U mines and structures. Plant biota samples (N = 32) and corresponding soil sources were collected. The samples were analyzed using Inductively Coupled Plasma−Mass Spectrometry. In general, the study findings showed that metal(loid)s were concentrated greatest in soil > root > aboveground plant parts, respectively. Several medicinal plant samples were found to exceed the World Health Organization Raw Medicinal Plant Permissible Level for As and Cd; however, using the calculated human intake data, Reference Dietary Intakes, Recommended Dietary Allowances, and tolerable Upper Limits, the levels were not exceeded for those with established food intake or ingestion guidelines. There does not appear to be a dietary food rise of metal(loid) ingestion based solely on the eight medicinal plants examined. Food intake recommendations informed by research are needed for those who may be more sensitive to metal(loid) exposure. Further research is needed to identify research gaps and continued surveillance and monitoring are recommended for mining-impacted communities.

Association between Selenium Status and Chronic Kidney Disease in Middle-Aged and Older Chinese Based on CHNS Data

Background: The association between selenium and chronic kidney disease (CKD) remains controversial. Population studies with large samples facilitate the reliability of conclusions. Objective: In this study, we aimed to describe the prevalence of a CKD association with selenium intake in middle-aged and older Chinese. Methods: Data for this study were obtained from the China Health and Nutrition Survey (CHNS). A total of 5381 participants (aged ≥ 45) with biochemical test data were included in the study. Logistic regression models were used to examine the association between diet selenium intake (quartile) and the prevalence of CKD. Results: A total of 942 (17.01%) participants had CKD. The prevalence of CKD was 23.33%, 20.32%, 14.98%, and 9.25% among participants with average selenium intakes of 21.5 ± 4.82, 33.1 ± 2.79, 43.8 ± 3.70, and 67.0 ± 13.97 µg/day, respectively. In the fully adjusted model (Model 3), across the quartiles of selenium intake, the ORs for the prevalence of CKD were 1.00, 1.09 (95% CI 0.69–1.73), 0.82 (95% CI 0.49–1.38), and 0.43 (95% CI 0.22–0.85). The protein intake had a certain diagnostic significance for the selenium intake. Conclusions: An adequate selenium intake may have a positive effect on CKD. The influence of individual weight and location on the effect of selenium on CKD needs to be further explored.

Effects of co-exposure to multiple metals on children's behavior problems in China

Exposure to single metals have been linked to childhood behavior problems, But little is known about the effects of metals mixtures on children. We aimed to evaluate associations of multiple metals exposures in urine with childhood behavior in China. For this population-based study, the children eligible for inclusion provided urine samples and their parents agreed to take in-person interview. A total of 831 children were remained from three cities for the final analysis. Urinary metals concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS). The childhood behavior scores was calculated by the Conners' Parent Rating Scale (CPRS). Variable selection was achieved by the least absolute shrinkage and selection operator (LASSO) regularization and stepwise regression to for all metals in the study. Linear regression models and Bayesian kernel machine regression (BKMR) were applied to estimate the associations of urinary metals concentrations with children's behavior. In BKMR models, the overall effect of mixture was significantly associated with conduct problems, learning problems and hyperactive index when urinary metals concentrations were all above the 50th percentile compared to all of them at their medians. The models also suggested marginally significant interaction effects of Se and Fe as well as Se and Sb (P_Se∗Fe = 0.063; P_Se∗Sb = 0.061), with a decline in estimate of Se on learning problems when Sb/Fe levels were relatively high. The concentrations of 22 metals in boys were higher than girls. In summary, multiple metals are associated with an increased risk of childhood behavioral problems in China. Potential interaction effects of Se and Fe as well as Se and Sb on childhood behavior should be taken into consideration.

Biochemical diagnosis of Wilson's disease: an update

Wilson's disease (WD) is an inherited disorder of copper metabolism caused by mutations in the ATP7B gene. This condition is characterized by the accumulation of copper in the liver and other organs and tissues causing hepatic and neuropsychiatric manifestations. This paper reviews the diagnostic performance and limitations of the biochemical tests commonly used to detect this underdiagnosed disease. It also provides some recommendations and suggests a set of standardized laboratory comments. At present, a rapid, simple, reliable biochemical test that confirms diagnosis of WD is not available. However, diagnosis can be established based on serum ceruloplasmin and urinary copper excretion. Total serum copper should be employed with caution, since it has a low negative predictive value. The use of estimated non-ceruloplasmin-bound copper is not recommended. Nevertheless, measured relative exchangeable copper has very high sensitivity and specificity and emerges as a potential gold standard for the biochemical diagnosis of WD. The development of novel assays for WD detection makes this disorder a potential candidate to be included in newborn screening programs.

Assessing the Association of Element Imbalances With Arsenism and the Potential Application Value of Rosa roxburghii Tratt Juice

Endemic arsenism caused by coal burning is a unique type of biogeochemical disease that only exists in China, and it is also a disease of element imbalances. Previous studies have shown that element imbalances are involved in the pathogenesis of arsenic; however, the interaction between the various elements and effective preventive measures have not been fully studied. This study first conducted a cross-sectional study of a total of 365 participants. The results showed that arsenic exposure can increase the content of elements (Al, As, Fe, Hg, K, and Na) in the hair (p < 0.05), but the content of other elements (Ca, Co, Cu, Mn, Mo, P, Se, Sr, V, and Zn) was significantly decreased (p < 0.05). Also, the high level of As, Fe, and Pb and the low level of Se can increase the risk of arsenism (p < 0.05). Further study found that the combined exposure of Fe–As and Pb–As can increase the risk of arsenism, but the combined exposure of Se–As can reduce the risk of arsenism (p < 0.05). In particular, a randomized, controlled, double-blind intervention study reveals that Rosa roxburghii Tratt juice (RRT) can reverse the abovementioned element imbalances (the high level of Al, As, and Fe and the low level of Cu, Mn, Se, Sr, and Zn) caused by arsenic (p < 0.05). Our study provides some limited evidence that the element imbalances (the high level of As, Fe, and Pb and the low level of Se) are the risk factors for the occurrences of arsenism. The second major finding was that RRT can regulate the element imbalances, which is expected to improve arsenism. This study provides a scientific basis for further understanding a possible traditional Chinese health food, RRT, as a more effective detoxication of arsenism.

Assessing the Role of Nrf2/GPX4-Mediated Oxidative Stress in Arsenic-Induced Liver Damage and the Potential Application Value of Rosa roxburghii Tratt [Rosaceae]

Arsenic poisoning is a geochemical disease that seriously endangers human health. The liver is one of the important target organs for arsenic poisoning, several studies have shown that oxidative stress plays an important role in arsenic-induced liver damage. However, the specific mechanism of arsenic-induced oxidative stress has not yet been fully elucidated, and currently, there are no effective intervention measures for the prevention and treatment of arsenic-induced liver damage. In this study, the effect of the Nrf2/GPX4 signaling pathway and oxidative stress in the arsenic-induced liver damage was first evaluated. The results show that arsenic can activate the Nrf2/GPX4 signaling pathway and increase the oxidative stress, which in turn promotes arsenic-induced liver damage in MIHA cells. Moreover, when we applied the Nrf2 inhibitor, the promoting effect of arsenic on liver damage was alleviated by inhibiting the activation of the Nrf2/GPX4 signaling pathway. Subsequently, the Rosa roxburghii Tratt [Rosaceae] (RRT) intervention experiments in cells and arsenic poisoning population were designed. The results revealed that RRT can inhibit Nrf2/GPX4 signaling pathway to reduce oxidative stress, thereby alleviates arsenic-induced liver damage. This study provides some limited evidence that arsenite can activate Nrf2/GPX4 signaling pathway to induce oxidative stress, which in turn promotes arsenic-induced liver damage in MIHA cells. The second major finding was that Kaji-ichigoside F1 may be a potential bioactive compound of RRT, which can inhibit Nrf2/GPX4 signaling pathway to reduce oxidative stress, thereby alleviates arsenic-induced liver damage. Our study will contribute to a deeper understanding of the mechanisms in arsenic-induced liver damage, these findings will identify a possible natural medicinal food dual-purpose fruit, RRT, as a more effective prevention and control strategies for arsenic poisoning.

Association of Metals and Metalloids With Urinary Albumin/Creatinine Ratio: Evidence From a Cross-Sectional Study Among Elderly in Beijing

Background

Environmental exposure to toxic elements contributes to the pathogenesis of chronic kidney disease (CKD). Few studies focus on the association of urinary metals and metalloids concentrations with the urinary albumin/creatinine ratio (UACR) among elderly, especially in areas and seasons with severe air pollution.

Objective

We aimed to evaluate the associations of urinary metals and metalloids concentration with UACR, which is an early and sensitive indicator of CKD.

Method

We conducted a cross-sectional study among 275 elderly people in Beijing from November to December 2016, which has experienced the most severe air pollution in China. We measured 15 urinary metals and metalloids concentration and estimated their association with UACR using a generalized linear model (GLM). Bayesian kernel machine regression (BKMR) and quantile g-computation (qgcomp) models were also conducted to evaluate the combined effect of metal and metalloid mixtures concentration.

Results

Of the 275 elderly people included in the analysis, we found that higher urinary Cu concentration was positively associated with UACR using GLM (β = 0.36, 95% CI: 0.25, 0.46). Using the BKMR model, we found that the change in UACR was positively associated with a change in urinary Cu concentration from its 25th to 75th percentile value with all other metals and metalloids concentration fixed at their 25th, 50th, or 75th percentile levels. Urinary Cu concentration had the most significant positive contribution (59.15%) in the qgcomp model. Our finding was largely robust in three mixture modeling approaches: GLM, qgcomp, and BKMR.

Conclusion

This finding suggests that urinary Cu concentration was strongly positively associated with UACR. Further analyses in cohort studies are required to corroborate this finding.

Genetically Predicted Circulating Copper and Risk of Chronic Kidney Disease: A Mendelian Randomization Study

Elevated circulating copper levels have been associated with chronic kidney disease (CKD), kidney damage, and decline in kidney function. Using a two sample Mendelian randomization approach where copper-associated genetic variants were used as instrumental variables, genetically predicted higher circulating copper levels were associated with higher CKD prevalence (odds ratio 1.17; 95% confidence interval 1.04, 1.32; p-value = 0.009). There was suggestive evidence that genetically predicted higher copper was associated with a lower estimated glomerular filtration rate and a more rapid kidney damage decline. In conclusion, we observed that elevated circulating copper levels may be a causal risk factor for CKD.

Association of Night Shift Work With Chronic Spontaneous Urticaria and Effect Modification by Circadian Dysfunction Among Workers

Purpose: Night shift work is common in the current working environment and is a risk factor for many diseases. The study aimed to explore the relationship between night shift work with chronic spontaneous urticaria (CSU), and the modification effect of circadian dysfunction on it. Methods: A cross-sectional survey was conducted among Chinese workers. Exposure was measured by night work history and duration. Circadian dysfunction was characterized by excessive daytime sleepiness (EDS). The diagnosis of CSU was made by dermatologists who were investigating on the spot. The effect size was expressed as odds ratios (ORs). Results: A total of 8,057 participants were recruited, and 7,411 (92%) with complete information were included in the final analyses. The prevalence rates of CSU for workers without night shift and those with night shift history were 0.73 and 1.28%, respectively. Compared with workers who never worked night shifts, the risk of CSU increased with the length of night shift work: OR = 1.55 (95% confidence interval [CI]: 0.78-3.06) for duration <5 years and OR = 1.91 (95% CI: 1.12-3.26) for duration ≥5 years. EDS s EDS has been shown to modify this combination. Among workers without EDS, there was no association between night shift and CSU (OR = 0.94; 95% CI: 0.49-1.79). Whereas, in participants with EDS, the correlation was significant (OR = 3.58; 95% CI: 1.14-11.20). However, the effect modification by sleep disturbance was not observed. Conclusions: Night shift work is a risk factor for CSU, and there is a dose-response relationship between night shift work hours and the risk of CSU. This connection may be modified by circadian dysfunction.

Correlation between urinary contents of some metals and fasting plasma glucose levels: A cross-sectional study in China

Many metals are involved in the pathogenesis of diabetes, but most of existing studies focused on single metals. The study of mixtures represents real-life exposure scenarios and deserves attention. This study aimed to explore the potential relationship of urinary copper (Cu), zinc (Zn), arsenic (As), selenium (Se), and strontium (Sr) contents with fasting plasma glucose (FPG) levels in 2766 participants. The levels of metals in urine were determined by inductively coupled plasma-mass spectrometry. We used linear regression models and the Bayesian kernel machine regression (BKMR) to evaluate the association between metals and FPG levels. In the multiple metals linear regression, Zn (β = 0.434), Se (β = 0.172), and Sr (β = -0.143) showed significant association with FPG levels (all P < 0.05). The BKMR model analysis showed that the results of single metal association were consistent with the multiple metals linear regression. The mixture of five metals had a positive over-all effect on FPG levels, and Zn (PIP = 1.000) contributed the most to the FPG levels. Cu and As were negatively correlated with FPG levels in women. The potential interaction effect between Cu and Sr was observed in participants aged ≥ 60 years old (Pinteraction = 0.035). In summary, our results suggested that multiple metals in urine are associated with FPG levels. Further studies are needed to confirm these findings and clarify the underlying mechanisms.

Ameliorative role of rolipram, PDE-4 inhibitor, against sodium arsenite-induced vascular dementia in rats

Arsenic exposure to the population leads to serious health problems like neurotoxicity, nephrotoxicity, and cardiovascular abnormality. In the present study, the work has been commenced to discover the prospect of rolipram a phosphodiestrase-4 (PDE-4) inhibitor against sodium arsenite (SA)-induced vascular endothelial dysfunction (EnDF) leading to dementia in rats. Wistar rats were treated with SA (5 mg/kg body weight/day orally) for 44 days for induction of vascular EnDF and dementia. Learning and memory were evaluated using Morris water maze (MWM) test. Vascular EnDF was evaluated using aortic ring preparation. Various biochemical parameters were also evaluated like brain oxidative stress (viz. reduced glutathione and thiobarbituric acid reactive substances level), serum nitrite/nitrate activity, acetylcholinesterase activity, and inflammatory markers (viz. neutrophil infiltration in brain and myeloperoxidase). SA-treated rats showed poor performance in water maze trials indicating attenuated memory and ability to learn with significant rise (p < 0.05) in brain acetylcholinesterase activity, brain oxidative stress, neutrophil count, and significant decrease (p < 0.05) in serum nitrite/nitrate levels and vascular endothelial functions. Rolipram (PDE-4 inhibitor) treatment (0.03 mg/kg and 0.06 mg/kg body weight, intraperitoneally daily for 14 days) significantly improved memory and learning abilities, and restored various biochemical parameters and EnDF. It is concluded that PDE-4 modulator may be considered the prospective target for the treatment of SA-induced vascular EnDF and related dementia.

Association of multi-metals exposure with intelligence quotient score of children: A prospective cohort study

BACKGROUND

Associations between most single metals and children's intelligence quotient (IQ) scores have been evaluated in previous studies. However, associations between multi-metal exposures and children's IQ scores have not been analyzed.

OBJECTIVES

To assess the joint effects of lead (Pb), manganese (Mn), antimony (Sb), tin (Sn) and titanium (Ti) co-exposure on children's IQ scores.

METHODS

A prospective cohort study was conducted in Shimen and Huayuan, Hunan Province, China. Urine metals levels were measured by inductively coupled plasma mass spectrometry (ICP-MS) at baseline. Children's IQ scores were repeatedly measured at baseline and follow-up following the method of Raven's Standard Progressive Matrices (SPM) and standardized as z scores. We fitted linear regression models and Bayesian kernel machine regression (BKMR) models to investigate the associations of metal levels with children's IQ scores after adjusting for covariates.

RESULTS

A total of 633 participants aged 7-10 years completed the survey. Urinary Pb (β = -0.028, P = 0.022) and urinary Ti (β = -0.0003, P = 0.001) were inversely associated with children's IQ scores. The BKMR analyses revealed significant negative overall effects of the five metals on children's IQ scores when all the metals were above their median levels, while significant positive associations were shown when all the metal concentrations were below their median levels. The model also showed negative trends of Sn and Ti on children's IQ. Furthermore, Ti and Sn had a synergistic relationship, with a decline in IQ score when Sn exposure was relatively high. The urinary Sn concentration was significantly higher but the urinary Ti concentration was significantly lower in participants from the Shimen area than in those from the Huayuan area. Decreasing trends of the overall effects were observed in both the Shimen and Huayuan areas.

CONCLUSION

Our findings revealed that multi-metal exposures caused a decline in children's IQ scores according to traditional linear regression models and the BKMR model. Our results provide some evidence of the association between multi-metal exposure and children's IQ. Meanwhile, interactions between multi-metal exposures on children's IQ should be given more attention.

Association Between Prenatal Exposure to Metals and Atopic Dermatitis Among Children Aged 4 Years in Taiwan

IMPORTANCE

The prevalence of atopic dermatitis has substantially increased in recent decades, and atopic dermatitis could lead to allergic airway inflammation later in life. A previous study found that inorganic arsenic exposure was associated with allergic airway inflammation in children aged 8 to 14 years. However, the association between prenatal exposure to arsenic and other metals and the risk of atopic dermatitis among young children remains unknown.

OBJECTIVE

To assess the association between prenatal exposure to arsenic and other metals and the occurrence of atopic dermatitis in children at age 4 years.

DESIGN, SETTING, AND PARTICIPANTS

In total, 1152 pregnant women were enrolled in the original Taiwan Maternal and Infant Cohort Study (TMICS), a multicenter birth cohort study conducted at 9 hospitals in northern, central, southern, and eastern Taiwan from October 2012 to May 2015. Of those, 586 mothers and children aged 4 years participated in follow-up questionnaire interviews from August 2016 to January 2019. After excluding 216 participants with missing data, the final statistical analysis of follow-up data included 370 mother and child pairs from the central and eastern regions of Taiwan. Data were analyzed from February 2 to August 12, 2021.

EXPOSURES

Arsenic, cadmium, lead, cobalt, copper, nickel, thallium, and zinc during pregnancy.

MAIN OUTCOMES AND MEASURES

The outcome was parent-reported atopic dermatitis history among children aged 4 years. The presence of atopic dermatitis was defined as a positive response to the question, "Has your child ever had atopic dermatitis diagnosed by a physician?" During the initial TMICS study period, concentrations of arsenic, cadmium, lead, cobalt, copper, nickel, thallium, and zinc were measured in maternal urine during the third trimester of pregnancy using an inductively coupled plasma mass spectrometer. Estimated total inorganic arsenic exposure was calculated using a model that included data on both total arsenic and arsenic species (arsenite, arsenate, monomethylarsonate, and dimethylarsenate) obtained from a previous TMICS cohort.

RESULTS

Among 370 children included in the analysis, the mean (SD) age was 3.94 (0.59) years; 208 children (56.2%) were male, and 267 children (72.2%) were from the central region of Taiwan. A total of 110 children (29.7%) had atopic dermatitis at age 4 years. Maternal estimated total inorganic arsenic exposure during pregnancy was associated with increased odds of atopic dermatitis among children at age 4 years (odds ratio [OR], 2.42 [95% CI, 1.33-4.39] for every doubled increase of total inorganic arsenic) after adjusting for parental allergies, child's sex, geographic area, maternal educational level, and exposure to tobacco smoke. Every increased unit in the weighted quantile sum index of maternal metal exposure was significantly associated with atopic dermatitis (OR, 1.63; 95% CI, 1.28-2.07). Arsenic (40.1%) and cadmium (20.5%) accounted for most of the metal mixture index.

CONCLUSIONS AND RELEVANCE

This cohort study found that prenatal exposure to inorganic arsenic and coexposure to inorganic arsenic and cadmium were associated with a higher risk of atopic dermatitis in young children. These findings suggest that prevention of exposure to inorganic arsenic and cadmium during pregnancy may be helpful for the control of atopic dermatitis and other potential allergies in children.

Betaine attenuates sodium arsenite-induced renal dysfunction in rats

Exposure to higher levels of arsenic is a serious threat affecting human health worldwide. We investigated the protective role of betaine (N,N,N-trimethylglycine) against sodium arsenite-induced renal dysfunction in rats. Sodium arsenite (5 mg/kg, oral) was given to rats for 4 weeks to induce nephrotoxicity. Betaine (125 and 250 mg/kg, oral) was administered in rats for 4 weeks along with sodium-arsenite feeding. Arsenic-induced renal dysfunction was demonstrated by measuring serum creatinine, creatinine clearance, urea, uric acid, potassium, fractional excretion of sodium, and microproteinuria. Oxidative stress in rat kidneys was determined by assaying thiobarbituric acid reactive substances, superoxide anion generation, and reduced glutathione levels. Furthermore, hydroxyproline assay was done to assess renal fibrosis in arsenic intoxicated rats. Hematoxylin-eosin and picrosirius red staining revealed pathological alterations in rat kidneys. Renal endothelial nitric oxide synthase (eNOS) expression was determined by immuno-histochemistry. Concurrent administration of betaine abrogated arsenic-induced renal biochemical and histological changes in rats. Betaine treatment significantly attenuated arsenic-induced decrease in renal eNOS expression. In conclusion, betaine is protective against sodium arsenite-induced renal dysfunction, which may be attributed to its anti-oxidant activity and modulation of renal eNOS expression in rat kidneys.