The combined effect of heavy metals and polycyclic aromatic hydrocarbons on arthritis, especially osteoarthritis, in the U.S. adult population

Molecular mechanisms of environmental pollutant-induced cartilage damage: from developmental disorders to osteoarthritis

The objective of the present study was to review the molecular mechanisms of the adverse effects of environmental pollutants on chondrocytes and extracellular matrix (ECM). Existing data demonstrate that both heavy metals, including cadmium (Cd), lead (Pb), and arsenic (As), as well as organic pollutants, including polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCB), bisphenol A, phthalates, polycyclic aromatic hydrocarbons (PAH), pesticides, and certain other organic pollutants that target cartilage ontogeny and functioning. Overall, environmental pollutants reduce chondrocyte viability through the induction apoptosis, senescence, and inflammatory response, resulting in cell death and impaired ECM production. The effects of organic pollutants on chondrocyte development and viability were shown to be mediated by binding to the aryl hydrocarbon receptor (AhR) signaling and modulation of non-coding RNA expression. Adverse effects of pollutant exposures were observed in articular and growth plate chondrocytes. These mechanisms also damage chondrocyte precursors and subsequently hinder cartilage development. In addition, pollutant exposure was shown to impair chondrogenesis by inhibiting the expression of Sox9 and other regulators. Along with altered Runx2 signaling, these effects also contribute to impaired chondrocyte hypertrophy and chondrocyte-to-osteoblast trans-differentiation, resulting in altered endochondral ossification. Several organic pollutants including PCDD/Fs, PCBs and PAHs, were shown to induce transgenerational adverse effects on cartilage development and the resulting skeletal deformities. Despite of epidemiological evidence linking human environmental pollutant exposure to osteoarthritis or other cartilage pathologies, the data on the molecular mechanisms of adverse effects of environmental pollutant exposure on cartilage tissue were obtained from studies in laboratory rodents, fish, or cell cultures and should be carefully extrapolated to humans, although they clearly demonstrate that cartilage should be considered a putative target for environmental pollutant toxicity.

Sphingobium sp. SJ10-10 encodes a not-yet-reported chromate reductase and the classical Rieske dioxygenases to simultaneously degrade PAH and reduce chromate

Both polycyclic aromatic hydrocarbons (PAHs) and heavy metals persist in the environment and are toxic to organisms. Their co-occurrence makes any of them difficult to remove during bioremediation and poses challenges to environmental management and public health. Microorganisms capable of effectively degrading PAHs and detoxifying heavy metals concurrently are required to improve the bioremediation process. In this study, we isolated a new strain, Sphingobium sp. SJ10-10, from an abandoned coking plant and demonstrated its capability to simultaneously degrade 92.6 % of 75 mg/L phenanthrene and reduce 90 % of 3.5 mg/L hexavalent chromium [Cr(VI)] within 1.5 days. Strain SJ10-10 encodes Rieske non-heme iron ring-hydroxylating oxygenases (RHOs) to initiate PAH degradation. Additionally, a not-yet-reported protein referred to as Sphingobium chromate reductase (SchR), with low sequence identity to known chromate reductases, was identified to reduce Cr(VI). SchR is distributed across different genera and can be classified into two classes: one from Sphingobium members and the other from non-Sphingobium species. The widespread presence of SchR in those RHO-containing Sphingobium members suggests that they are excellent candidates for bioremediation. In summary, our study demonstrates the simultaneous removal of PAHs and Cr(VI) by strain SJ10-10 and provides valuable insights into microbial strategies for managing complex pollutant mixtures.

Analyzing the impact of heavy metal exposure on osteoarthritis and rheumatoid arthritis: an approach based on interpretable machine learning

Introduction

This investigation leverages advanced machine learning (ML) techniques to dissect the complex relationship between heavy metal exposure and its impacts on osteoarthritis (OA) and rheumatoid arthritis (RA). Utilizing a comprehensive dataset from the National Health and Nutrition Examination Survey (NHANES) spanning from 2003 to 2020, this study aims to elucidate the roles specific heavy metals play in the incidence and differentiation of OA and RA.

Methods

Employing a phased ML strategy that encompasses a range of methodologies, including LASSO regression and SHapley Additive exPlanations (SHAP), our analytical framework integrates demographic, laboratory, and questionnaire data. Thirteen distinct ML models were applied across seven methodologies to enhance the predictability and interpretability of clinical outcomes. Each phase of model development was meticulously designed to progressively refine the algorithm's performance.

Results

The results reveal significant associations between certain heavy metals and an increased risk of arthritis. The phased ML approach enabled the precise identification of key predictors and their contributions to disease outcomes.

Discussion

These findings offer new insights into potential pathways for early detection, prevention, and management strategies for arthritis associated with environmental exposures. By improving the interpretability of ML models, this research provides a potent tool for clinicians and researchers, facilitating a deeper understanding of the environmental determinants of arthritis.

Weight change patterns across adulthood are associated with the risk of osteoarthritis: a population-based study

BACKGROUND

Body weight has been recognized as a driving factor of osteoarthritis. Few studies had investigated the association between weight status across adulthood and risk of osteoarthritis (OA). This study investigates the association of weight change patterns across adulthood (lasting at least 25 years) with the risk of OA from the National Health and Nutrition Examination Survey (NHANES) 2013-2018.

METHODS

The study assessed the relationship between weight change across adulthood and OA in 7392 individuals aged > 50 spanning a minimum of 25 years. Multivariate linear regression analyses were utilized to detect the association between weight change patterns and self-reported OA. Restricted cubic splines (RCS) were used to examine the nonlinear relationship between absolute weight change and OA risk.

RESULTS

From 10 years ago to survey, the risk of OA was 1.34-fold (95% CI 1.07-1.68) in people changed from obese to non-obese, 1.61-fold (95% CI 1.29-2.00) in people change from non-obese to obese, and 1.82-fold (95% CI 1.49-2.22) in stable obese people compared with people who were at stable normal weight. Similar patterns were also observed at age 25 years to baseline and age 25 years to 10 years before the baseline. The dose-response association of RCS found a U-shaped relationship between absolute weight change and OA risk.

CONCLUSIONS

The study suggests that weight patterns across adulthood are associated with the risk of OA. These findings stressed important to maintain a normal weight throughout adulthood, especially to prevent ignored weight gain in early adulthood to reduce OA risk later.

Depression heightened the association of the systemic immune-inflammation index with all-cause mortality among osteoarthritis patient

BACKGROUND

Systemic immune-inflammatory index (SII) has been recognized as a novel inflammatory indicator in numerous diseases. It remains unknown how SII affects all-cause mortality among patients with osteoarthritis (OA). In this prospective cohort study, we intended to examine the relationship of SII with all-cause mortality among OA populations and assess the interaction between depression and SII.

METHODS

Data was collected from National Health and Nutrition Examination Survey (NHANES) in 2005-2018. The National Death Index (NDI) provided vital status records. Multivariable Cox regression analyses with cubic spines were applied to estimate the association between SII and all-cause and CVD mortality. Stratified analysis and interaction tests assessed the interaction of SII and depression on all-cause mortality.

RESULTS

In total 3174 OA adults were included. The lowest quartile Q1 (HR:1.44, 95%CI:1.02-2.04) and highest quartile Q4 (HR:1.44, 95%CI:1.02-2.04) of SII presented a higher risk of death compared with those in second quartile Q2 (Ref.) and third quartile Q3 (HR:1.23, 95%CI:0.89-1.68. Restricted cubic splines analysis revealed a U-shaped association of SII with all-cause mortality, the inflection points were 412.93 × 109/L. The interaction test observed a more significant relationship of SII with all-cause mortality in depression patients than in non-depression patients, indicating that depression can modify this association.

LIMITATIONS

First, the observational study design failed to make causal inferences. Second, the baseline SII cannot reflect the long-term level of inflammation. Finally, there may be potential bias.

CONCLUSION

SII was U-shaped associated with all-cause mortality in OA patients, and this association was significantly heightened by depression.

Contributions of Synthetic Chemicals to Autoimmune Disease Development and Occurrence

PURPOSE OF REVIEW

Exposure to many synthetic chemicals has been linked to a variety of adverse human health effects, including autoimmune diseases. In this scoping review, we summarize recent evidence detailing the effects of synthetic environmental chemicals on autoimmune diseases and highlight current research gaps and recommendations for future studies.

RECENT FINDINGS

We identified 68 recent publications related to environmental chemical exposures and autoimmune diseases. Most studies evaluated exposure to persistent environmental chemicals and autoimmune conditions including rheumatoid arthritis (RA), systemic lupus (SLE), systemic sclerosis (SSc), and ulcerative colitis (UC) and Crohn's disease. Results of recent original research studies were mixed, and available data for some exposure-outcome associations were particularly limited. PFAS and autoimmune inflammatory bowel diseases (UC and CD) and pesticides and RA appeared to be the most frequently studied exposure-outcome associations among recent publications, despite a historical research focus on solvents. Recent studies have provided additional evidence for the associations of exposure to synthetic chemicals with certain autoimmune conditions. However, impacts on other autoimmune outcomes, particularly less prevalent conditions, remain unclear. Owing to the ubiquitous nature of many of these exposures and their potential impacts on autoimmune risk, additional studies are needed to better evaluate these relationships, particularly for understudied autoimmune conditions. Future research should include larger longitudinal studies and studies among more diverse populations to elucidate the temporal relationships between exposure-outcome pairs and to identify potential population subgroups that may be more adversely impacted by immune modulation caused by exposure to these chemicals.

Association between glyphosate exposure and osteoarthritis in US adults: Especially in people who are obese and inactive in leisure time physical activity

OBJECTIVE

Little has been known on the effect of chronic glyphosate exposure on osteoarthritis (OA). The aim of this study was to investigate the association between glyphosate exposure and OA and to further investigate the different moderating effects of leisure time physical activity (LTPA) and body mass index (BMI) types on the association between glyphosate exposure and OA.

METHODS

Cross-sectional data from 2540 participants in the 2015-2018 National Health and Nutrition Examination Survey (NHANES) were used to explore the association between glyphosate exposure and OA. Multivariate logistic regression models and restricted cubic spline models were used to investigate the association between glyphosate exposure and OA, and further analyses were conducted to determine the association between glyphosate exposure and OA under different LTPA and BMI types.

RESULTS

Of the 2540 participants, 346 had OA. Participants with the highest glyphosate concentration (Q4) had a higher incidence of OA compared to participants with the lowest glyphosate concentration (Q1) (OR, 1.88; 95 % confidence interval [CI]: 1.13, 3.13), there was no nonlinear association between glyphosate and OA (non-linear P = 0.343). In the no LTPA group, glyphosate concentration in the Q4 group was correlated with OA (OR, 2.65; 95%CI: 1.27, 5.51). In the obese group, glyphosate concentration in the Q4 group was correlated with OA (OR, 2.74; 95 % CI: 1.48, 5.07). Among people with high BMI and inactive in LTPA, glyphosate concentrations in Q4 were associated with OA (OR, 2.19; 95 % CI: 1.07, 4.48).

CONCLUSIONS

Glyphosate is associated with OA odd, and physical activity and moderate weight loss can mitigate this association to some degree. This study provides a scientific basis for rational prevention of OA by regulation of LTPA and BMI under glyphosate exposure.

Independent and combined associations of polycyclic aromatic hydrocarbons exposure and sleep disorders among adults in the U.S. adult population

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are prevalent organic pollutants in the environment; however, limited research has been conducted to explore their potential effects on sleep disorders. This study aims to investigate the relationship between single and mixed PAHs exposures and sleep disorders.

METHODS

This study analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2016, involving 7730 adult participants. To examine the relationship between PAHs exposure and sleep disorders, we employed survey-weighted multivariate logistic regression models and restricted cubic spline (RCS) models to evaluate single PAHs exposure. Additionally, we employed three mixed-exposure models to examine the relationship between combined PAHs exposure and sleep disorders.

RESULTS

After adjusting for covariates, our analyses revealed positive associations between several urinary PAHs metabolites (1-hydroxynaphthalene (1-NAP), 2-NAP, 3-hydroxyfluorene (3-FLU), 2-FLU, and 1-hydroxypyrene (1-PYR)) and sleep disturbance. Consistency across various analytical methods underscores a discernible positive correlation between simultaneous exposure to PAHs and sleep disorders. This association is predominantly influenced by the presence of NAP and FLU. Remarkably, a positive relationship between combined PAHs exposure and sleep disorders emerged within the younger and middle-aged demographic but did not manifest within the elderly population.

CONCLUSION

In conclusion, our study provides new epidemiological evidence suggesting that both single and mixed PAHs exposures may increase the risk of sleep disorders. Further prospective investigations are necessary to validate these findings.

Association between polycyclic aromatic hydrocarbons and periodontitis: Results from a large population-based study

AIM

To explore the association between polycyclic aromatic hydrocarbons (PAHs) (measured using urinary metabolites) and periodontitis using data from the National Health and Nutrition Examination Survey 2009-2014.

MATERIALS AND METHODS

Weighted binary logistic regression, Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression were used to evaluate independent and joint associations between the six urinary monohydroxylated metabolites of PAHs (OH-PAHs) and periodontitis.

RESULTS

In all, 3413 participants were included in this study. All six urinary OH-PAHs were present at higher levels in the periodontitis group compared with the non-periodontitis group (p < .001). Fully adjusted multivariable logistic regressions showed positive associations between the six urinary OH-PAHs and periodontitis (p < .05). Higher concentrations of OH-PAHs were also positively associated with attachment loss, periodontal pocket depth (PPD) and the number of tooth loss. BKMR and WQS regression yielded similar positive associations between OH-PAH mixtures and periodontitis.

CONCLUSIONS

PAHs and their mixture are positively associated with periodontitis, which may provide novel insights into periodontitis prevention from an environmental exposure perspective.

Associations of perchlorate, nitrate, and thiocyanate exposure with arthritis and inflammation indicators in young and middle-aged adults, NHANES 2005-2016

Background

Perchlorates, nitrates, and thiocyanates are prevalent environmental chemicals. Their potential association with arthritis remains unexplored. This study aimed to investigate the link between perchlorate, nitrate, and thiocyanate exposure and arthritis, as well as the potential role of inflammation in this context.

Methods

Utilizing the National Health and Nutrition Examination Survey (NHANES) data spanning from 2005 to 2016, the study enrolled 6597 participants aged 20-59 (young and middle-aged), of which 1045 had arthritis. Employing multivariate logistic regression modeling, multiple linear regression models, restricted cubic spline analysis, Bayesian kernel machine regression (BKMR) modeling, and mediation analysis, we assessed these relationships.

Results

There was a significant positive association between elevated urinary thiocyanate levels and arthritis risk [1.19 (1.11, 1.28)]. This association held true across subgroups of osteoarthritis (OA) [1.24 (1.10, 1.40)] and rheumatoid arthritis (RA) [1.33 (1.15, 1.55)]. Thiocyanate levels displayed a dose-dependent relationship with arthritis risk, showing a linear trend (nonlinear P > 0.05). Conversely, perchlorate and nitrate did not exhibit associations with arthritis risk. BKMR outcomes highlighted a positive correlation between a mixture of perchlorate, nitrate, and thiocyanate and arthritis risk, with thiocyanate being the predominant predictors. Moreover, BKMR and generalized linear model analyses unveiled no significant synergistic effect of urinary perchlorate, nitrate, and thiocyanate on arthritis risk. Furthermore, thiocyanate exposure has been linked to elevated levels of inflammatory indicators (white blood cell, neutrophils, lymphocytes, and systemic immune-inflammatory index (SII)).

Conclusion

Heightened thiocyanate exposure may be linked to elevated arthritis risk, either single or in combined effects. Additionally, thiocyanate exposure is associated with heightened inflammation levels.

Joint association of heavy metals and polycyclic aromatic hydrocarbons exposure with depression in adults

BACKGROUND

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) represent significant components of environmental pollution, typically occurring as mixtures, raising concerns about their potential impact on human health. However, the combined effect of HMs and PAHs exposure on depression has not been explored.

METHODS

Leveraging National Health and Nutrition Examination Survey (NHANES) data spanning 2005 to 2016, we employ survey-weighted multiple logistic regression models to probe the interrelation between HMs, PAHs, and depression. This exploration is complemented by age and gender-stratified analyses, as well as a determination of the dose-response linkage via restricted cubic spline regression. Furthermore, the combined impact of HMs and PAHs on depression was evaluated through a range of statistical methodologies.

RESULTS

The study encompasses 7732 adults. Our findings unveil notable associations, indicating the significant influence of cadmium (Cd), lead (Pb), and all six PAHs metabolites on depression. Moreover, mixed exposure to HMs and PAHs emerges as a substantial contributor to an augmented depression risk, with Cd, Pb, 1-hydroxynaphthalene (1-NAP), 2-hydroxyfluorene (2-FLU), and 1-hydroxypyrene (1-PYR) likely driving this positive relationship. Intriguingly, subgroup analyses highlight greater prominence of these connections among individuals aged 20-59 and among women. Furthermore, the results tentatively suggest a potential interplay between Cd and 2-NAP in relation to depression.

CONCLUSION

This study posits that exposure to both individual and combined HMs and PAHs may be associated with an elevated risk of depression. Further prospective investigations are warranted to substantiate these findings.

Whole-body aging mediates the association between exposure to volatile organic compounds and osteoarthritis among U.S. middle-to-old-aged adults

BACKGROUND

Humans are constantly exposed to various volatile organic compounds (VOCs) because of their widespread sources and characteristic of easy evaporation. Existing evidence regarding the association between VOC exposure and osteoarthritis (OA) risk is limited.

PURPOSE

This study aimed to investigate the associations between individual urinary VOC metabolites (VOCMs) and the VOCM mixture, representing internal exposure levels of VOCs, with prevalent OA risk and to explore the mediating effect of aging and oxidative stress (OS) in these associations.

METHODS

Data from the National Health and Nutrition Examination Surveys 2005-2020 were analyzed. Weighted generalized linear regression was employed to explore the associations between individual VOCMs and OA risk, as well as aging and OS biomarkers. A five-repeated ten-fold cross-validation elastic net model was used to identify critical VOCMs for the weight quantile sum (WQS) analysis, which was performed to explore the VOCM mixture and OA risk association. Parallel and serial mediation analyses were conducted to identify the potential mediators and mediation pathways.

RESULTS

This study included 6578 American adults aged ≥40 years, among whom 1052 (16.0 %) individuals reported prevalent OA. Urinary levels of N-acetyl-S-(benzyl)-L-cysteine, mandelic acid and phenylglyoxylic acid were positively associated with OA risk. Eleven VOCMs with nonzero coefficients were identified and included in the WQS analysis, and results revealed an average increase of 24.4 % in OA risk (OR = 1.244, 95 % CI: 1.041, 1.486) per one-quantile increment in the VOCM mixture. Two aging biomarkers, phenotypic age and biological age, parallelly mediated the association between the VOCM mixture and OA risk, with mediation effect proportions of 9.0 % and 16.4 %, respectively.

CONCLUSIONS

Exposure to VOCs is associated with an increased OA risk in middle-to-old aged American adults. The mediating effect of aging contributes to the association between co-exposure to VOCs and OA risk. Further prospective studies are required to substantiate these findings.

Physical activity modifies the association of the composite dietary antioxidant index with all-cause mortality in the US osteoarthritis population

Background

It remains unclear how antioxidant intake affects all-cause mortality in osteoarthritis (OA) patients. In this prospective cohort study, we aim to explore the association of the Composite Dietary Antioxidant Index (CDAI) with all-cause mortality and investigate the interaction of physical activity (PA) and CDAI on all-cause mortality in OA populations.

Methods

A total of 3,197 adults with OA in the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018 were included in this study. Death outcomes were obtained from National Death Index (NDI) records. Multivariable Cox regression analyses with cubic spines were applied to estimate the association of CDAI with all-cause mortality. The interaction between CDAI and PA on all-cause mortality was further assessed in stratified analysis and interaction tests.

Results

The hazard ratios for all-cause mortality were 0.95 (0.77-1.17) for Q2, 0.75 (0.59-0.97) for Q3, and 0.71 (0.55-0.92) for Q4 (P for trend <0.001), compared with the lowest quartile of CDAI. A negative linear association was found between CDAI and all-cause mortality. In the stratified analyses, CDAI was negatively associated with all-cause mortality in the insufficient PA group. While in the low and sufficient PA group, there were nonlinear relationships of CDAI with all-cause mortality.

Conclusion

A negative linear relationship was observed between CDAI and all-cause mortality in OA patients, and this association was significantly modified by PA. Higher intake of dietary antioxidants might be the interventional objective to reduce the risk of all-cause mortality in the US OA population.

Association of urinary heavy metal combined exposure with periodontitis among US adults from NHANES 2011-2014

Some heavy metals are associated with periodontitis; whereas most of these associations have focused on individual metal, there are no specific studies on the effects of combined heavy metal exposure on periodontitis. We conducted an analysis on the association between urinary heavy metal exposure and periodontitis in participants aged 30 years and older using multiple logistic regression and Bayesian kernel machine regression (BKMR). This analysis was performed on data from the National Health and Nutrition Examination Survey from 2011 to 2014. The study found that using logistic regression, the 4th quartile of urinary lead and molybdenum and the 3rd quartile of urinary strontium were positively associated with periodontitis compared to the reference quartile after adjusting for covariates. Odds ratio (OR) with 95% confidence interval (CI) was 1.738 (1.069-2.826), 1.515 (1.025-2.239), and 1.498 (1.010-2.222), respectively. The 3rd and 4th quartiles of urinary cobalt were negatively associated with periodontitis, and their ORs and 95% CIs were 0.639 (0.438-0.934) and 0.571 (0.377-0.964), respectively. The BKMR model showed that urinary barium, lead, and molybdenum were positively associated with periodontitis in a range of concentrations and urinary cobalt, manganese, tin, and strontium were negatively correlated with periodontitis. Furthermore, the overall association between urinary heavy metals and periodontitis was positive. Our study provides evidence for an association between exposure to multiple urinary heavy metals and periodontitis. However, further longitudinal studies are needed to explore the specific mechanisms involved.

Association between brominated flame retardants exposure and markers of oxidative stress in US adults: An analysis based on the National Health and Nutrition Examination Survey 2007-2016

We aimed to investigate the relationship between oxidative stress indicators and brominated flame retardant (BFR) levels in US adults. Using data from the NHANES (National Health and Nutrition Examination Survey) from 2007 to 2016, 8028 participants aged 18 and over were enrolled in this study. PBDE28, PBDE47, PBDE85, PBDE99, PBDE100, PBDE153, PBDE154, PBDE209, and PBB153, with over 75 % detection rates, were extracted in this study. Survey-weighted linear regression model, weighted quantile sum (WQS) model, and quantile-based g calculation (QGC) model were used to assess the correlation between serum BFRs levels and oxidative stress indicators (serum bilirubin and gamma-glutamyl transferase [GGT]). Besides, the nonlinear association was explored using restricted cubic splines (RCS). Each of the BFRs was confirmed by the survey-weighted linear regression model to be positively associated with GGT after controlling for variables, and BFRs except for PBDE153 were positively associated with serum bilirubin. Except for PBDE153, serum bilirubin in the highest quartile of BFRs was significantly higher than in the lowest high quartile. Additionally, except for PBDE85, serum GGT in the highest quartile of BFRs was higher than in the lowest high quartile. A significant nonlinear association between all BFRs with bilirubin and the PBDE153, PBDE209, and PBB153 with GGT was identified by RCS analysis. By WQS analysis, combined BFR exposure was associated with serum GGT (β: 0.093; 95 % CI = 0.066-0.121; P < 0.0001) and bilirubin (β: 0.090; 95 % CI = 0.068-0.113; P < 0.0001). QGC analysis found a similar correlation between BFR mixtures with serum GGT (β: 0.098; 95 % CI = 0.075-0.120; P < 0.0001) and bilirubin (β: 0.073; 95 % CI = 0.048-0.097; P < 0.0001). Exposure to BFRs is positively associated with markers of oxidative stress (serum bilirubin and GGT) in US adults, which needs further exploration by a large-scale cohort study.

Associations of exposure to heavy metal mixtures with kidney stone among U.S. adults: A cross-sectional study

Assessing the effects of heavy metals (HMs) on kidney stone is often limited to analyzing individual metal exposures, with studies on the effects of exposure to mixtures of HMs being scarce. To comprehensively evaluate the relationship between exposure to mixed HMs and kidney stones, we analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2007-2016, which included 7809 adults. We used multiple statistical methods, including multiple logistic regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp) and bayesian kernel machine regression (BKMR), to assess the association between single HM and mixed exposure to HMs and kidney stones. Firstly, in single exposure analysis, urinary cadmium (Cd) and cobalt (Co) demonstrated a positive association with the risk of kidney stones. Secondly, various other approaches consistently revealed that mixed exposure to HMs exhibited a positive association with kidney stone risk, primarily driven by Cd, Co, and barium (Ba) in urine, with these associations being particularly notable among the elderly population. Finally, both BKMR and survey-weighted generalized linear models consistently demonstrated a significant synergistic effect between urinary Co and urinary uranium (Ur) in elevating the risk of kidney stones. Overall, this study provides new epidemiological evidence that mixed exposure to HMs is associated with an increased risk of kidney stones. Further prospectively designed studies are needed to confirm these findings.