Associations of essential trace elements with epigenetic aging indicators and the potential mediating role of inflammation

Associations between serum trace elements and biological age acceleration in the Chinese elderly: A community-based study investigating the mediating role of inflammatory markers and the moderating effect of physical activity

Growing evidence suggests that environmental factors play a significant role in the aging process. We established the Klemera and Doubal Method biological age acceleration (KDM-BAA) by using the KDM as a biological age predictor to assess the trace elements (ELEs) role. Generalized Linear Model (GLM) was used to assess the associations between single ELE (trace element) and KDM-BAA. Restricted cubic splines (RCS) were used to assess the nonlinear relationship between elemental levels and KDM-BAA. Quantile G-Computation (QGC) regression was employed to explore the direction and weight. Weighted Quantile Sum (WQS) Regression was used to study the weights of different groups of ELEs. Bayesian Kernel Machine Regression (BKMR) was utilized to analyze the overall effect of mixed elemental exposure. Mediation analysis was conducted to investigate the role of intermediate biomarkers and the moderating effects of physical activity (PA) was used on the pathway. The results showed serum Copper (Cu) levels positively correlated with KDM-BAA, while Zinc (Zn) and Iron (Fe) negatively correlated with it, respectively. The mixture of Zn, Cobalt (Co), Selenium (Se), and Fe exhibited a significant overall negative effect. Additionally, PA could ease the association between Cu and KDM-BAA through impacting the inflammation level. This study provides novel insights into how inflammation mediates the association between ELEs exposure and KDM-BAA, while PA acts as a potential protective factor.

Associations of greenhouse gases, air pollutants and dynamics of scrub typhus incidence in China: a nationwide time-series study

BACKGROUND

Environmental factors have been identified as significant risk factors for scrub typhus. However, the impact of inorganic compounds such as greenhouse gases and air pollutants on the incidence of scrub typhus has not been evaluated.

METHODS

Our study investigated the correlation between greenhouse gases, air pollutants from the global atmospheric emissions database (2005-2018), and reported cases of scrub typhus from the Public Health Science Data Center. First, an early warning method was applied to estimate the epidemic threshold and the grading intensity threshold. Second, four statistical methods were used to assess the correlation and lag effects across different age groups and epidemic periods. Deep learning algorithms were employed to evaluate the predictive effect of environmental factors on the incidence of scrub typhus.

RESULTS

Using the Moving Epidemic Method (MEM) and Treed Distributed Lag Non-Linear Model (TDLNM), we found that the period from April to September is the epidemic season for scrub typhus in China. During this period, BC, CH4, NH3 and PM10 all reach key windows during their respective early warning lag periods. Interaction effects showed that increased CO exposure during the 0-2-month period led to an increased magnitude of the PM10 effect during the 3-7-month period. The Quantile-based G Computation (qgcomp) model revealed age-specific differences in susceptibility to environmental factors. In the Bayesian Kernel Machine Regression (BKMR) model, we identified NOx (RRmax (95% CI) = 103.14 (70.40, 135.87)) and NMVOC as the risk environmental factors for young adults, while CH4 (RRmax (95% CI) = 20.94 (9.26, 32.63)) was significantly associated with scrub typhus incidence in younger populations. For the elderly, N2O and NOx (RRmax (95% CI) = 30.23 (13.78, 46.68)) were identified as susceptibility factors for scrub typhus. The Weighted Quantile Sum (WQS) model revealed a significant risk effect of NOx on scrub typhus during periods of low risk, which are often overlooked (OR (95% CI) = 0.40 (0.23, 0.58)). During periods of medium to high risk, Convolutional Neural Networks (CNN) showed that environmental factors performed well in predicting the incidence of scrub typhus.

CONCLUSIONS

We found that most greenhouse gases and air pollutants increase the risk of contracting scrub typhus, mainly driven by CH4, NOx, and NMVOC. Among these, the primary high-level pollutants have long-term lag effects during the epidemic period. The correlation between environmental factors and scrub typhus incidence varies significantly across different age groups and risk periods. Among them, middle-aged and young individuals are more susceptible to the effects of exposure to mixed air pollutants. CNN algorithm can help develop a comprehensive early warning system for scrub typhus. These findings may have important implications for guiding effective public health interventions in the future. The primary interventions should focus on controlling greenhouse gas emissions and reducing air pollutants, which can, in turn, be used to support infectious disease monitoring systems through environmental monitoring. Moreover, given the cross-sectional approach of our study, these findings need to be confirmed through additional cohort studies.

Selenium alleviates cadmium-induced biological aging acceleration and the potential mediating role of inflammation

Aging and heavy metal pollution are global challenges, and cadmium (Cd) may negatively affect aging. However, effective interventions for Cd toxicity among populations remain insufficient. Selenium (Se) is recognized for its protective effects against heavy metal toxicity and aging. This study utilized data from the National Health and Nutrition Examination Survey (2015-2018) to explore the individual and joint effects of Cd and Se on biological aging acceleration, measured by Klemera-Doubal method biological age acceleration (KDM-BA-Accel) (n = 7119) and Phenotypic age acceleration (PhenoAge-Accel) (n = 7433). Results showed that Cd was positively associated with KDM-BA-Accel (β = 0.57) and PhenoAge-Accel (β = 0.77), while Se had negative associations with both (β values were -4.01 and -5.30, respectively). Nonlinear analyses revealed J-shaped associations for Cd and L-shaped for Se with aging indicators. Moreover, inflammation significantly mediated the Cd-aging and Se-aging relationships. Most importantly, a significant negative interaction between Cd and Se on PhenoAge-Accel (β for interaction = -1.29) suggested an antagonistic effect, particularly among never smokers. Increasing Se content can mitigate the harmful effects of Cd on PhenoAge-Accel were demonstrated through three methods. Specifically, ⅰ) compared to "Cd (-) & Se (-)" group, "Cd (+) & Se (-)" group had β = 0.87, while "Cd (+) & Se (+)" group was non-significant; ⅱ) higher Se content was associated with a lower increase in PhenoAge-Accel as Cd content rose; ⅲ) there were no significant associations between Cd & Se mixture and aging indicators (both p > 0.310). These findings highlight Se supplementation as a potential strategy to counteract Cd-induced aging, offering a new direction for public health interventions in polluted populations.

The molecular mechanism and therapeutic landscape of copper and cuproptosis in cancer

Copper, an essential micronutrient, plays significant roles in numerous biological functions. Recent studies have identified imbalances in copper homeostasis across various cancers, along with the emergence of cuproptosis, a novel copper-dependent form of cell death that is crucial for tumor suppression and therapeutic resistance. As a result, manipulating copper levels has garnered increasing interest as an innovative approach to cancer therapy. In this review, we first delineate copper homeostasis at both cellular and systemic levels, clarifying copper's protumorigenic and antitumorigenic functions in cancer. We then outline the key milestones and molecular mechanisms of cuproptosis, including both mitochondria-dependent and independent pathways. Next, we explore the roles of cuproptosis in cancer biology, as well as the interactions mediated by cuproptosis between cancer cells and the immune system. We also summarize emerging therapeutic opportunities targeting copper and discuss the clinical associations of cuproptosis-related genes. Finally, we examine potential biomarkers for cuproptosis and put forward the existing challenges and future prospects for leveraging cuproptosis in cancer therapy. Overall, this review enhances our understanding of the molecular mechanisms and therapeutic landscape of copper and cuproptosis in cancer, highlighting the potential of copper- or cuproptosis-based therapies for cancer treatment.

Low blood levels of selenium, selenoprotein P and GPx3 are associated with accelerated biological aging: results from the Berlin Aging Study II (BASE-II)

BACKGROUND

Biological age reflects inter-individual differences in biological function and capacity beyond chronological age. DNA methylation age (DNAmA) and its deviation from chronological age, DNAmA acceleration (DNAmAA), which was calculated as residuals of leukocyte cell count adjusted linear regression of DNAmA on chronological age, were used to estimate biological age in this study. Low levels of serum selenium, selenoprotein P (SELENOP), and the selenocysteine-containing glutathione peroxidase 3 (GPx3) are associated with adverse health outcomes and selenium supplementation is discussed as an anti-aging intervention.

METHODS

In this study, we cross-sectionally analyzed 1568 older participants from the observational Berlin Aging Study II (mean age ± SD: 68.8 ± 3.7 years, 51% women). Serum selenium was measured by total reflection X-ray fluorescence (TXRF) spectroscopy and SELENOP was determined by sandwich ELISA. GPx3 was assessed as part of a proteomics dataset using liquid chromatography-mass spectrometry (LC-MS). The relationship between selenium biomarkers and epigenetic clock measures was analyzed using linear regression analyses. P values and 95% confidence intervals (not adjusted for multiple testing) are stated for each analysis.

RESULTS

Participants with deficient serum selenium levels (< 90 μg/L) had a higher rate of biological aging (DunedinPACE, β = - 0.02, SE = 0.01, 95% CI - 0.033 to - 0.004, p = 0.010, n = 865). This association remained statistically significant after adjustment for age, sex, BMI, smoking, and first four genetic principal components (β = - 0.02, SE = 0.01, 95% CI - 0.034 to - 0.004, p = 0.012, n = 757). Compared to the highest quartile, participants in the lowest quartile of SELENOP levels showed an accelerated biological aging rate (DunedinPACE, β = - 0.03, SE = 0.01, 95% CI - 0.051 to - 0.008, p = 0.007, n = 740, fully adjusted model). Similarly, after adjustment for confounders, accelerated biological age was found in participants within the lowest GPx3 quartile compared to participants in the fourth quartile (DunedinPACE, β = - 0.04, SE = 0.01, 95% CI - 0.06 to - 0.02, p = 0.001, n = 674 and GrimAge, β = - 0.98, SE = 0.32, 95% CI - 1.6 to - 0.4, p = 0.002, n = 608). Only the association with GPx3 remained statistically significant after multiple testing correction.

CONCLUSION

Our study suggests that low levels of selenium biomarkers are associated with accelerated biological aging measured through epigenetic clocks. This effect was not substantially changed after adjustment for known confounders.

Associations between serum metal mixtures and systemic inflammation indices among Chinese early adolescents: A prospective cohort study

BACKGROUND

Research has demonstrated a link between metal exposure and inflammation. However, little is known about this relationship among adolescents, especially in prospective cohort studies. The aim of this study was to investigate the relationship between serum metal exposure and inflammatory status in Chinese early adolescents.

METHODS

In this study, 12 serum metals were detected at baseline in 1551 participants from the Chinese Early Adolescents Cohort. The participants' inflammatory status was assessed via three systemic inflammation indices (neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII)) at both baseline and follow-up. Generalized linear mixed models and restricted cubic splines regression were used to examine the linear and nonlinear relationships between single metal concentrations and systemic inflammation indices. Multiple mixture models were implemented to assess the relationships of mixed metals with systemic inflammation indices. Additionally, sex subgroup analyses were conducted to explore the sex-specific associations between serum metals and inflammatory status.

RESULTS

Single-exposure analysis revealed that exposure to multiple serum metals, such as chromium, cobalt, copper and lead, was positively associated with the NLR and SII, whereas iron was negatively correlated with the three systemic inflammation indices (PFDR<0.05). Additionally, inverted U-shaped associations were observed between vanadium, manganese and systemic inflammation indices. According to the mixture models, high levels of the serum metal mixture were positively correlated with the NLR and the SII. Cobalt had the highest positive weight in the mixed samples, whereas iron had the greatest negative weight in the serum-metal mixtures. Subgroup analyses revealed that serum exposure to the metal mixture had a more significant effect on systemic inflammation markers in females than in males.

CONCLUSIONS

This study reveals the impact of real-world mixed metal exposure on adolescents' inflammatory levels, which is of primary significance for protecting the healthy development of early adolescents.

Changes of CA19-9 levels and related influencing factors in patients with type 2 diabetes mellitus after antidiabetic therapy

Abnormalities of carbohydrate antigen 19 - 9 (CA19-9) are common in patients with type 2 diabetes mellitus (T2DM), and in some patients, CA19-9 returns to normal level after glycemic control. The aim of this study was to investigate the factors associated with CA19-9 levels in patients with T2DM and the associated influences on the degree of reduction of CA19-9 levels after antidiabetic therapy (AT). This study was an observational cross-sectional study. A total of 213 patients with T2DM were enrolled in this study, of whom 105 with abnormal CA19-9 and 108 with normal CA19-9. Socio-demographic information, complete blood counts, biochemical indicators, thyroid function indicators, and CA19-9 level were collected separately for each subject. Levels of glycosylated hemoglobin, type A1C (HbA1c), fasting blood glucose (FBG) were significantly higher in T2DM patients with abnormal CA19-9 compared to patients with normal CA19-9 (both FDR < 0.001). CA19-9 level was significantly and positively correlated with neutrophil/lymphocyte ratio (NLR) (r = 0.16, P = 0.02), monocyte/lymphocyte ratio (MLR) (r = 0.16, P = 0.02), and FBG (r = 0.38, P < 0.001), while significantly and negatively correlated with free triiodothyronine (FT3) (r=-0.22, P = 0.002) and albumin count (r=-0.18, P = 0.007). After AT, the degree of decrease in CA19-9 level in T2DM patients with abnormal CA19-9 was significantly positively correlated with degree of decrease in FBG (r = 0.33, P < 0.001), as well as CA19-9 level before AT (r = 0.73, P < 0.001), NLR (r = 0.20, P = 0.04), and MLR (r = 0.25, P = 0.01). In this study, we investigated the influencing factors associated with CA19-9 level and the factors influencing degree of CA19-9 reduction after AT in T2DM patients with abnormal CA19-9.

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

BACKGROUND

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

OBJECTIVE

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

RESULTS

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

CONCLUSION

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

Analysis of dietary inflammatory potential and mortality in cancer survivors using NHANES data

Background

In the United States, cancer is a leading cause of mortality, with inflammation playing a crucial role in cancer progression and prognosis. Diet, with its capacity to modulate inflammatory responses, represents a potentially modifiable risk factor in cancer outcomes.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHANES, 1999-2018) to investigate the association between the Dietary Inflammatory Index (DII), which reflects dietary-induced inflammation, and mortality among cancer survivors. A total of 3,011 participants diagnosed with cancer were included, with DII scores derived from dietary recall data. All-cause and cancer-related mortalities served as primary endpoints.

Results

The study identified a significant linear positive correlation between higher DII scores and all-cause mortality among cancer survivors. Each unit increase in DII was associated with a 10% higher risk of all-cause mortality (hazard ratio [HR] per 1-unit increase, 1.10; 95% confidence interval [CI], 1.04-1.15). Similarly, a unit increase in DII was associated with a 13% higher risk of cancer-related mortality (HR per 1-unit increase, 1.13; 95% CI, 1.02-1.25). Kaplan-Meier analyses demonstrated higher all-cause mortality rates in individuals with elevated DII scores. Sensitivity analyses confirmed the robustness of these findings.

Conclusion

Adoption of an anti-inflammatory diet, characterized by lower DII scores, may improve survival outcomes in cancer survivors. These results emphasize the critical role of dietary interventions in post-cancer care.

Low-grade systemic inflammation links heavy metal exposures to mortality: A multi-metal inflammatory index approach

Certain heavy metals have been correlated to an elevated risk of inflammation-related diseases and mortality. Nevertheless, the intricate relationships between metal exposure, inflammation and mortality remain unknown. We included 3741 adults with measurements of ten urinary heavy metals in the National Health and Nutritional Examination Survey (NHANES) 2005-2010, followed up to December 31, 2019. Low-grade systemic inflammation was evaluated by various markers, including C-reactive protein (CRP) and ratios derived from regular blood tests. We assessed associations between heavy metal and all-cause mortality using multivariate COX regressions. Then we assessed the mediation effect of low-grade systemic inflammation on the associations via Sobel Test. To gauge the systemic inflammatory potential of the multi-metal mixture and its correlation with all-cause mortality, a Metal Mixture Inflammatory Index (MMII) was developed using reduced rank regression (RRR) models. The association between MMII and all-cause mortality was explored via multivariate COX regressions. Cadmium, antimony and uranium displayed positive associations with mortality, with hazard ratios (HR) ranging from 1.18 to 1.46 (all P-FDR < 0.05). Mediation analyses revealed that the associations between specific heavy metals (cadmium and antimony) and mortality risk were slightly mediated by the low-grade systemic inflammation markers, with mediation proportions ranging from 3.11 % to 5.38 % (all P < 0.05). MMII, the weighted sum of 9 heavy metals, significantly predicted platelet-to-lymphocyte ratio (PLR) and CRP (β = 0.10 and 1.16, all P < 0.05), was positively associated with mortality risk (HR 1.28, 95 % CI 1.14 to 1.43). Exposure to heavy metals might increase all-cause mortality, partly mediated by low-grade systemic inflammation. MMII, designed to assess the potential systemic inflammatory effects of exposure to multiple heavy metals, was closely related to the all-cause mortality risk. This study introduces MMII as an approach to evaluating co-exposure and its potential health effects comprehensively.

Supplementation of Micro- and Macronutrients-A Role of Nutritional Status in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a condition in which the pathological cumulation of fat with coexisting inflammation and damage of hepatic cells leads to progressive dysfunctions of the liver. Except for the commonly well-known major causes of NAFLD such as obesity, dyslipidemia, insulin resistance, or diabetes, an unbalanced diet and imbalanced nutritional status should also be taken into consideration. In this narrative review, we summarized the current knowledge regarding the micro- and macronutrient status of patients suffering from NAFLD considering various diets and supplementation of chosen supplements. We aimed to summarize the knowledge indicating which nutritional impairments may be associated with the onset and progression of NAFLD at the same time evaluating the potential therapy targets that could facilitate the healing process. Except for the above-mentioned objectives, one of the most important aspects of this review was to highlight the possible strategies for taking care of NAFLD patients taking into account the challenges and opportunities associated with the micronutrient status of the patients. The current research indicates that a supplementation of chosen vitamins (e.g., vitamin A, B complex, C, or D) as well as chosen elements such as zinc may alleviate the symptoms of NAFLD. However, there is still a lack of sufficient data regarding healthy ranges of dosages; thus, further research is of high importance in this matter.

Association between multiple-heavy-metal exposures and systemic immune inflammation in a middle-aged and elderly Chinese general population

BACKGROUND

Exposure to heavy metals alone or in combination can promote systemic inflammation. The aim of this study was to investigate potential associations between multiple plasma heavy metals and markers of systemic immune inflammation.

METHODS

Using a cross-sectional study, routine blood tests were performed on 3355 participants in Guangxi, China. Eight heavy metal elements in plasma were determined by inductively coupled plasma mass spectrometry. Immunoinflammatory markers were calculated based on peripheral blood WBC and its subtype counts. A generalised linear regression model was used to analyse the association of each metal with the immunoinflammatory markers, and the association of the metal mixtures with the immunoinflammatory markers was further assessed using weighted quantile sum (WQS) regression.

RESULTS

In the single-metal model, plasma metal Fe (log10) was significantly negatively correlated with the levels of immune-inflammatory markers SII, NLR and PLR, and plasma metal Cu (log10) was significantly positively correlated with the levels of immune-inflammatory markers SII and PLR. In addition, plasma metal Mn (log10 conversion) was positively correlated with the levels of immune inflammatory markers NLR and PLR. The above associations remained after multiple corrections. In the mixed-metal model, after WQS regression analysis, plasma metal Cu was found to have the greatest weight in the positive effects of metal mixtures on SII and PLR, while plasma metals Mn and Fe had the greatest weight in the positive effects of metal mixtures on NLR and LMR, respectively. In addition, blood Fe had the greatest weight in the negative effects of the metal mixtures for SII, PLR and NLR.

CONCLUSION

Plasma metals Cu and Mn were positively correlated with immunoinflammatory markers SII, NLR and PLR. While plasma metal Fe was negatively correlated with immunoinflammatory markers SII, NLR, and PLR.

DNA methylation aging signatures of multiple metals exposure and their mediation effects in metal-associated mortality: Evidence from the Dongfeng-Tongji cohort study

Humans were exposed to multiple metals, but the impact of metals on DNA methylation-age (DNAm-age), a well-recognized aging measure, remains inconclusive. This study included 2942 participants from the Dongfeng-Tongji cohort. We detected their plasma concentrations of 23 metals and determined their genome-wide DNA methylation using the Illumina Human-MethylationEPIC BeadChip. Five DNAm-age acceleration indexes (DAIs), including HannumAge-Accel, HorvathAge-Accel, PhenoAge-Accel, GrimAge-Accel (residual from regressing corresponding DNAm-age on chronological age) and DNAm-mortality score (DNAm-MS), were separately calculated. We found that each 1-unit increase in ln-transformed copper (Cu) was associated with a separate 1.02-, 0.83- and 0.07-unit increase in PhenoAge-Accel, GrimAge-Accel, and DNAm-MS (all FDR<0.05). Each 1-unit increase in ln-transformed nickel (Ni) was associated with a 0.34-year increase in PhenoAge-Accel, while each 1-unit increase in ln-transformed strontium (Sr) was associated with a 0.05-unit increase in DNAm-MS. The Cu, Ni and Sr showed joint positive effects on above three DAIs. PhenoAge-Accel, GrimAge-Accel, and DNAm-MS mediated a separate 6.5%, 12.3%, 6.0% of the positive association between Cu and all-cause mortality; GrimAge-Accel mediated 14.3% of the inverse association of selenium with all-cause mortality. Our findings revealed the effects of Cu, Ni, Sr and their co-exposure on accelerated aging and highlighted mediation roles of DNAm-age on metal-associated mortality.

Serum albumin mediates the associations between heavy metals and two novel systemic inflammation indexes among U.S. adults

BACKGROUND

The effects of heavy metal exposure on immunological function have sparked widespread concern, but unequivocal evidence on the association between mixed metal exposure and novel systemic inflammatory indexes remains scarce.

OBJECTIVES

This study aimed to analyze the associations of heavy metals with two novel systemic inflammation indexes and the mediated effects of serum albumin.

METHODS

Nineteen metals were detected among 4082 U.S. adults based on the NHANES. A linear regression, restricted cubic splines (RCS) regression, weighted quantile sum (WQS), Quantile-based Gcomputation (qgcomp), and Bayesian kernel machine regression (BKMR) were conducted to evaluate the associations of single metal and mixed metals with systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) levels, respectively. A series of subgroup analyses were used to identify potentially vulnerable populations. Furthermore, we conducted mediation analyses to investigate the mediated effects of serum albumin on the associations of metals with SII and SIRI.

RESULTS

In the single-exposure model, exposure to various metals such as urinary Co, As, and serum Zn, Cu was associated with SII and SIRI (PFDR<0.05). Simultaneously, the above metals were linear positively correlated with SII and SIRI. Mixed-exposure analyses consistently showed that overall mixed urinary metal levels were positively pertinent for SII and SIRI levels, and the metal Co played a significant role in the urinary metal mixtures. Subgroup analyses showed that exposure to urinary Cd in men and elderly people increased SII and SIRI levels. The results of mediation analyses suggested the association of urinary metal mixture with SII and SIRI was mediated by albumin, and the proportion of mediation was 14.45% and 9.49%, respectively.

CONCLUSIONS

Our findings suggested that metal exposure is strongly associated with the levels of system inflammation indexes and that serum albumin is, in part, a mediator of this association.