Effect of exposures to mixtures of lead and various metals on hypertension, pre-hypertension, and blood pressure: A cross-sectional study from the China National Human Biomonitoring

Roles of serum uric acid on the association between arsenic exposure and incident metabolic syndrome in an older Chinese population

Growing evidences showed that heavy metals exposure may be associated with metabolic diseases. Nevertheless, the mechanism underlying arsenic (As) exposure and metabolic syndrome (MetS) risk has not been fully elucidated. So we aimed to prospectively investigate the role of serum uric acid (SUA) on the association between blood As exposure and incident MetS. A sample of 1045 older participants in a community in China was analyzed. We determined As at baseline and SUA concentration at follow-up in the Yiwu Elderly Cohort. MetS events were defined according to the criteria of the International Diabetes Federation (IDF). Generalized linear model with log-binominal regression model was applied to estimate the association of As with incident MetS. To investigate the role of SUA in the association between As and MetS, a mediation analysis was conducted. In the fully adjusted log-binominal model, per interquartile range increment of As, the risk of MetS increased 1.25-fold. Compared with the lowest quartile of As, the adjusted relative risk (RR) of MetS in the highest quartile was 1.42 (95% confidence interval, CI: 1.03, 2.00). Additionally, blood As was positively associated with SUA, while SUA had significant association with MetS risk. Further mediation analysis demonstrated that the association of As and MetS risk was mediated by SUA, with the proportion of 15.7%. Our study found higher As was remarkably associated with the elevated risk of MetS in the Chinese older adults population. Mediation analysis indicated that SUA might be a mediator in the association between As exposure and MetS.

Association of metals and bisphenols exposure with lipid profiles and dyslipidemia in Chinese adults: Independent, combined and interactive effects

BACKGROUND

Although studies have assessed the association of metals and bisphenols with lipid metabolism, the observed results have been controversial, and limited knowledge exists about the combined and interactive effects of metals and bisphenols exposure on lipid metabolism.

METHODS

Plasma metals and serum bisphenols concentrations were evaluated in 888 participants. Multiple linear regression and logistic regression models were conducted to assess individual associations of 18 metals and 3 bisphenols with 5 lipid profiles and dyslipidemia risk, respectively. The dose-response relationships of targeted contaminants with lipid profiles and dyslipidemia risk were captured by applying a restriction cubic spline (RCS) function. The bayesian kernel machine regression (BKMR) model was used to assess the overall effects of metals and bisphenols mixture on lipid profiles and dyslipidemia risk. The interactive effects of targeted contaminants on interested outcomes were explored by constructing an interaction model.

RESULTS

Single-contaminant analyses revealed that exposure to iron (Fe), nickel (Ni), copper (Cu), arsenic (As), selenium (Se), strontium (Sr), and tin (Sn) was associated with elevated lipid levels. Cobalt (Co) showed a negative association with high density lipoprotein cholesterol (HDL-C). Bisphenol A (BPA) and bisphenol AF (BPAF) were associated with decreased HDL-C levels, with nonlinear associations observed. Vanadium (V), lead (Pb), and silver (Ag) displayed U-shaped dose-response relationships with most lipid profiles. Multi-contaminant analyses indicated positive trends between contaminants mixture and total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C). The interaction analyses showed that Se-Fe exhibited synergistic effects on LDL-C and non-HDL-C, and Se-Sn showed a synergistic effect on HDL-C.

CONCLUSIONS

Our study suggested that exposure to metals and bisphenols was associated with changes in lipid levels, and demonstrated their combined and interactive effects.

Combined exposure to multiple metals on abdominal aortic calcification: results from the NHANES study

Exposure to metals increases the risk of many diseases and has become a public health concern. However, few studies have focused on the effect of metal on abdominal aortic calcification (AAC), especially the combined effects of metal mixtures. In this study, we aim to investigate the combined effect of metals on AAC risk and determine the key components in the multiple metals. We tried to investigate the relationship between multiple metal exposure and AAC risk. Fourteen urinary metals were analyzed with five statistical models as follows: generalized linear regression, weighted quantile sum regression (WQS), quantile g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) models. A total of 838 participants were involved, of whom 241 (28.8%) had AAC. After adjusting for covariates, in multiple metal exposure logistic regression, cadmium (Cd) (OR = 1.364, 95% CI = 1.035-1.797) was positively associated with AAC risk, while cobalt (Co) (OR = 0.631, 95% CI = 0.438-0.908) was negatively associated with AAC risk. A significant positive effect between multiple metal exposure and AAC risk was observed in WQS (OR = 2.090; 95% CI = 1.280-3.420, P < 0.01), Qgcomp (OR = 1.522, 95% CI = 1.012-2.290, P < 0.05), and BKMR models. It was found that the positive association may be driven primarily by Cd, lead (Pb), uranium (U), and tungsten (W). Subgroups analysis showed the association was more significant in participants with BMI ≥ 25 kg/m2, abdominal obesity, drinking, and smoking. Our study shows that exposure to multiple metals increases the risk of AAC in adults aged ≥ 40 years in the USA and that Cd, Pb, U, and W are the main contributors. The association is stronger in participants who are obese, smoker, or drinker.

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.

Effect of exposures to multiple metals on blood pressure and hypertension in the elderly: a community-based study

A chronic disease, hypertension (HTN) is prevalent among the elderly. Exploring the factors that influence HTN and blood pressure (BP) changes is of great public health significance. However, mixed exposure to multiple serum metals has had less research on the effects on BP and HTN for the elderly. From April to August 2019, 2372 people participated in the community physical examination program for the elderly in Tongling City, Anhui Province. We measured BP and serum levels of 10 metals and collected basic demographic information. We analyzed the relationship between metal levels and changes in BP and HTN by the least absolute shrinkage and selection operator regression, Bayesian kernel machine regression model, and generalized linear model. In multiple models, lead (Pb) and cadmium (Cd) were still significantly associated with HTN occurrence after adjusting for potential confounders (Pb: ORquartile 4 VS quartile 1 = 1.20, 95% CI 1.01-1.43; Cd: ORquartile 4 VS quartile 1 = 1.37, 95% CI 1.16-1.62). In the male subgroup, results were similar to those of the general population. In the female group, Cd was positively correlated with HTN and systolic blood pressure, while Pb was not. According to this study, Pb and Cd were correlated with BP and HTN positively, and there was a certain joint effect. To some extent, our findings provide clues for the prevention of hypertension in the elderly.

Environmental exposure to lead and cadmium are associated with triglyceride glucose index

The triglyceride glucose (TyG) index was suggested as a novel reliable surrogate marker for insulin resistance and related cardiovascular-metabolic diseases. We aimed to evaluate the association between the TyG index and environmental exposure to lead (Pb), mercury (Hg), and cadmium (Cd). A total of 9645 adults who enrolled in the Korea National Health and Nutrition Examination Survey in 2005, 2008-2013, and 2016 were included. Fasting plasma glucose and triglyceride levels were used to calculate the TyG index. Multivariate logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). We noted an increasing trend in the TyG index with increment of blood Pb and Cd concentrations. Participants in the highest quartile of blood Pb and Cd concentrations had higher TyG index values than those in the lowest quartile, with ORs (95% CIs) of 1.32 (1.07-1.63) and 1.29 (1.04-1.59) for Pb and Cd, respectively. Strong associations between blood Pb and Cd concentrations and the TyG index were found in men. Blood Hg concentrations did not show a significant association with the TyG index. Our study suggests that public health strategies for cardiovascular-metabolic disorder prevention should be directed toward individuals exposed to priority heavy metals.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

The Relationships Between Blood Pb Levels and Blood Pressure Among Lead-Exposed Workers in China: A Repeated-Measure Study

OBJECTIVES

To explore the differences in the increase of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in 3 consecutive years among lead (Pb) workers.

METHODS

Four hundred forty-eight Pb workers were enrolled in this repeated-measure study. Blood Pb, SBP, and DBP were measured in 2015 to 2017. Repeated measure of analysis of variance was used to compare the differences in the increase of SBP and DBP.

RESULTS

The mean SBP values were 124.0/125.5/126.9 mm Hg, and the mean DBP values were 75.4/77.4/77.8 mm Hg from 2015 to 2017. The differences in the increase of SBP and DBP were 2.94/2.42 mm Hg during the 3-year period. The average annual increase of SBP or DBP showed an upward trend in different Pb dose groups ( F = 4.904, P = 0.002; F = 3.612, P = 0.013).

CONCLUSIONS

Lead exposure caused average annual increases in SBP and DBP with 0.98 and 0.81 mm Hg, which provided basic data for health surveillance.

Association of Combined Metals and PFAS with Cardiovascular Disease Risk

This study sought to investigate the impact of exposure to metals and per- and polyfluoroalkyl substances (PFASs) on cardiovascular disease (CVD)-related risk. PFASs, including PFOA, PFOS, PFNA, and PFHxS, as well as metals such as lead (Pb), cadmium (Cd), and mercury (Hg), were analyzed to elucidate their combined effects on CVD risk.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2014, this investigation explored the effects of PFASs and metals on CVD risk. A spectrum of individual CVD markers, encompassing systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol, and triglycerides, was examined. Additionally, comprehensive CVD risk indices were evaluated, namely the Overall Cardiovascular Biomarkers Index (OCBI), including the Framingham Risk Score and an Overall Cardiovascular Index. Linear regression analysis was employed to probe the relationships between these variables. Furthermore, to assess dose-response relationships between exposure mixtures and CVD while mitigating the influence of multicollinearity and potential interaction effects, Bayesian Kernel Machine Regression (BKMR) was employed.

RESULTS

Our findings indicated that exposure to PFAS and metals in combination increased CVD risk, with combinations occurring with lead bringing forth the largest impact among many CVD-related markers.

CONCLUSIONS

This study finds that combined exposure to metals and PFASs significantly elevates the likelihood of CVD risk. These results highlight the importance of understanding the complex interplay between multipollutant exposures and their potential implications for cardiovascular health.

Insight into the effect of a heavy metal mixture on neurological damage in rats through combined serum metabolomic and brain proteomic analyses

The heavy metals lead (Pb), cadmium (Cd), and mercury (Hg) that cause neurocognitive impairment have been extensively studied. These elements typically do not exist alone in the environment; they are often found with other heavy metals and can enter the body through various routes, thereby impacting health. Our previous research showed that low Pb, Cd, and Hg levels cause neurobehavioral impairments in weaning and adult rats. However, little is known about the biomarkers and mechanisms underlying Pb, Cd, and Hg mixture-induced neurological impairments. A combined analysis of metabolomic and proteomic data may reveal heavy metal-induced alterations in metabolic and protein profiles, thereby improving our understanding of the molecular mechanisms underlying heavy metal-induced neurological impairments. Therefore, brain tissue and serum samples were collected from rats exposed to a Pb, Cd, and Hg mixture for proteomic and metabolomic analyses, respectively. The analysis revealed 363 differential proteins in the brain and 206 metabolites in serum uniquely altered in the Pb, Cd, and Hg mixture exposure group, compared to those of the control group. The main metabolic impacted pathways were unsaturated fatty acids biosynthesis, linoleic acid metabolism, phenylalanine metabolism, and tryptophan metabolism. We further identified that the levels of arachidonic acid (C20:4 n-3) and, adrenic acid (C22:4 n-3) were elevated and that kynurenic acid (KA) and quinolinic acid (QA) levels and the KA/QA ratio, were decreased in the group exposed to the Pb, Cd, and Hg mixture. A joint analysis of the proteome and metabolome showed that significantly altered proteins such as LPCAT3, SLC7A11, ASCL4, and KYAT1 may participate in the neurological impairments induced by the heavy metal mixture. Overall, we hypothesize that the dysregulation of ferroptosis and kynurenine pathways is associated with neurological damage due to chronic exposure to a heavy metal mixture.

Associations of prenatal and childhood Pb exposure with allostatic load in adolescence: Findings from the ELEMENT cohort study

The biological pathways which link lead (Pb) and long-term outcomes are unclear, though rodent models and a few human studies suggest Pb may alter the body's stress response systems, which over time, can elicit dysregulated stress responses with cumulative impacts. This study examined associations between prenatal and early childhood Pb exposure and adolescent allostatic load, an index of an individual's body burden of stress in multiple biological systems, and further examined sex-based associations. Among 391 (51% male) participants in the ELEMENT birth cohort, we related trimester-specific maternal blood Pb, 1-month postpartum maternal tibia and patella Pb, and child blood Pb at 12-24 months to an allostatic load index in adolescence comprised of biomarkers of cardiovascular, metabolic, neuroendocrine, and immune function. The results were overall mixed, with prenatal exposure, particularly maternal bone Pb, being positively associated with allostatic load, and early childhood Pb showing mixed results for males and females. In adjusted Poisson regression models, 1 mcg/g increase in tibia Pb was associated with a 1% change in expected allostatic load (IRR = 1.01; 95%CI 0.99, 1.02). We found a significant Pb × sex interaction (IRR = 1.05; 95%CI 1.01, 1.10); where males saw an increasing percent change in allostatic load as 12 month Pb levels increased compared to females who saw a decreasing allostatic load. Further examination of allostatic load will facilitate the determination of potential mechanistic pathways between developmental toxicant exposures and later-in-life cardiometabolic outcomes.

Exploring the association of metal mixture in blood to the kidney function and tumor necrosis factor alpha using machine learning methods

This research aimed to approach relationships between metal mixture in blood and kidney function, tumor necrosis factor alpha (TNF-α) by machine learning. Metals levels were measured by Inductively Couple Plasma Mass Spectrometry in blood from 421 participants. We applied K Nearest Neighbor (KNN), Naive Bayes classifier (NB), Support Vector Machines (SVM), random forest (RF), Gradient Boosting Decision Tree (GBDT), Categorical boosting (CatBoost), eXtreme Gradient Boosting (XGBoost), Whale Optimization-based XGBoost (WXGBoost) to identify the effect of plasma metals, TNF-α, and estimated glomerular filtration rate (eGFR by CKD-EPI equation). We conducted not only toxic metals, lead (Pb), arsenic (As), cadmium (Cd) but also included trace essential metals, selenium (Se), copper (Cu), zinc (Zn), cobalt (Co), to predict the interaction of TNF-α, TNF-α/white blood count, and eGFR. The high average TNF-α level group was observed among subjects with higher Pb, As, Cd, Cu, and Zn levels in blood. No associations were shown between the low and high TNF-α level group in blood Se and Co levels. Those with lower eGFR group had high Pb, As, Cd, Co, Cu, and Zn levels. The crucial predictor of TNF-α level in metals was blood Pb, and then Cd, As, Cu, Se, Zn and Co. The machine learning revealed that As was the major role among predictors of eGFR after feature selection. The levels of kidney function and TNF-α were modified by co-exposure metals. We were able to acquire highest accuracy of over 85% in the multi-metals exposure model. The higher Pb and Zn levels had strongest interaction with declined eGFR. In addition, As and Cd had synergistic with prediction model of TNF-α. We explored the potential of machine learning approaches for predicting health outcomes with multi-metal exposure. XGBoost model added SHAP could give an explicit explanation of individualized and precision risk prediction and insight of the interaction of key features in the multi-metal exposure.

Association of urinary thallium with hypertension in children and adolescents aged 8-17 years: NHANES 2005-2018

Hypertension is a key risk factor for cardiovascular disease (CVD). Thallium is a highly toxic metal that exists in all aspects of our lives and can cause damage to human health. The aim of this study was to identify the potential correlation between urinary thallium (U-Tl) and hypertension in American youth aged 8-17 years. The National Health and Nutritional Examination Survey (NHANES) database was mined for cross-sectional information on 2295 American children and adolescents aged 8-17 years. Inductively coupled plasma mass spectrometry (ICP-MS) was utilized to measure U-Tl levels, and the results were categorized into four quartiles (Q1-Q4). Logistic generalized linear models and unweighted restricted cubic spline (RCS) regression were used to investigate the relationship between U-Tl and hypertension. After adjusting for covariates, the odds ratios (ORs) at 95% confidence intervals (CIs) for hypertension prevalence in the 2nd, 3rd, and 4th quartiles were 0.43 (0.22-0.81), 0.54 (0.29-0.99), and 0.43 (0.22-0.81), when compared to the lowest quartile (P for trend = 0.024). RCS plot showed a negative linear correlation between log2-transformed U-Tl levels and hypertension (P for non-linearity = 0.869). Subgroup analysis based on sex indicated a statistically significant link between U-Tl and hypertension in male (P < 0.05). There is a negative linear relationship between U-Tl and hypertension in American children and adolescents aged 8-17 years with low thallium exposure. Due to the nature of cross-sectional studies, further studies are necessary to validate our conclusions and elucidate possible mechanisms.

Hippocampal LIMK1-mediated Structural Synaptic Plasticity in Neurobehavioral Deficits Induced by a Low-dose Heavy Metal Mixture

Humans are commonly exposed to the representative neurotoxic heavy metals lead (Pb), cadmium (Cd), and mercury (Hg). These three substances can be detected simultaneously in the blood of the general population. We have previously shown that a low-dose mixture of these heavy metals induces rat learning and memory impairment at human exposure levels, but the pathogenic mechanism is still unclear. LIM kinase 1 (LIMK1) plays a critical role in orchestrating synaptic plasticity during brain function and dysfunction. Hence, we investigated the role of LIMK1 activity in low-dose heavy metal mixture-induced neurobehavioral deficits and structural synaptic plasticity disorders. Our results showed that heavy metal mixture exposure altered rat fear responses and spatial learning at general population exposure levels and that these alterations were accompanied by downregulation of LIMK1 phosphorylation and structural synaptic plasticity dysfunction in rat hippocampal tissues and cultured hippocampal neurons. In addition, upregulation of LIMK1 phosphorylation attenuated heavy metal mixture-induced structural synaptic plasticity, dendritic actin dynamics, and cofilin phosphorylation damage. The potent LIMK1 inhibitor BMS-5 yielded similar results induced by heavy metal mixture exposure and aggravated these impairments. Our findings demonstrate that LIMK1 plays a crucial role in neurobehavioral deficits induced by low-dose heavy metal mixture exposure by suppressing structural synaptic plasticity.

Co-exposure to low-dose lead, cadmium, and mercury promotes memory deficits in rats: Insights from the dynamics of dendritic spine pruning in brain development

Lead (Pb), cadmium (Cd), and mercury (Hg) are environmentally toxic heavy metals that can be simultaneously detected at low levels in the blood of the general population. Although our previous studies have demonstrated neurodevelopmental toxicity upon co-exposure to these heavy metals at these low levels, the precise mechanisms remain largely unknown. Dendritic spines are the structural foundation of memory and undergo significant dynamic changes during development. This study focused on the dynamics of dendritic spines during brain development following Pb, Cd, and Hg co-exposure-induced memory impairment. First, the dynamic characteristics of dendritic spines in the prefrontal cortex were observed throughout the life cycle of normal rats. We observed that dendritic spines increased rapidly from birth to their peak value at weaning, followed by significant pruning and a decrease during adolescence. Dendritic spines tended to be stable until their loss in old age. Subsequently, a rat model of low-dose Pb, Cd, and Hg co-exposure from embryo to adolescence was established. The results showed that exposure to low doses of heavy metals equivalent to those detected in the blood of the general population impaired spatial memory and altered the dynamics of dendritic spine pruning from weaning to adolescence. Proteomic analysis of brain and blood samples suggested that differentially expressed proteins upon heavy metal exposure were enriched in dendritic spine-related cytoskeletal regulation and axon guidance signaling pathways and that cofilin was enriched in both of these pathways. Further experiments confirmed that heavy metal exposure altered actin cytoskeleton dynamics and disturbed the dendritic spine pruning-related LIM domain kinase 1-cofilin pathway in the rat prefrontal cortex. Our findings demonstrate that low-dose Pb, Cd, and Hg co-exposure may promote memory impairment by perturbing dendritic spine dynamics through dendritic spine pruning-related signaling pathways.

Combined exposure to multiple metals on hypertension in NHANES under four statistical models

Metals exposure has gained increasing attention in the hypertension prevention. However, previous studies have focused on the impacts of single or separated metals on hypertension, and the critical metals contributing to the prevalence of hypertension are still under discussion. We collected data from 5092 participants across three consecutive National Health and Nutrition Examination Survey (NHANES) circles (2011-2016). Weighted logistic regression, weighted quantile sum (WQS) regression, quantile-based g-computation (QGC), and Bayesian kernel machine regression (BKMR) analyses were conducted to evaluate the combined and individual effects of 15 urinary metals, as well as to identify the critical metals on the development of hypertension. In our study, the weighted prevalence of hypertension was 37.9%, and the average age was 47.42 years. Manganese, uranium and tin were found as the independent risk factors for hypertension, while barium, lead, and thallium were found to have protective effects against hypertension. Lead, barium, tungsten, uranium, and tin were determined as critical elements for the prediction of hypertension. No significant interaction relationship was detected between multiple metals. There might be potential positive combined effects of urinary metal mixture on hypertension. Tungsten, uranium, and tin were positively associated with hypertension while lead and barium were negatively associated with hypertension. The underlying mechanisms of urinary metal exposure on the risk of hypertension deserve further investigations.

Dose-response relationship between multiple trace elements and risk of all-cause mortality: a prospective cohort study

Objectives

We aimed to prospectively investigate the independent and combined relationship between trace elements concentrations [blood (selenium, manganese), serum (copper, zinc), and urine (cobalt, molybdenum, tin, strontium, iodine)] and all-cause mortality.

Methods

This study included 5,412 individuals with demographical, examination, and laboratory data from the National Health and Nutrition Examination Survey. Three statistical models, including Cox proportional hazards models, restricted cubic spline models, and Bayesian kernel machine regression (BKMR) models, were conducted to estimate the longitudinal relationship between trace elements and all-cause mortality.

Results

There were 356 deaths documented with a median follow-up time of 70 months. In the single-exposure model, the results showed that compared with the lowest quartile, the adjusted hazard ratios (HRs) of mortality for the highest quartile of selenium, manganese, and strontium were 0.47 (95% CI: 0.28-0.79), 1.57 (95% CI: 1.14-2.14), and 0.47 (95% CI: 0.26-0.86), respectively. A nonlinear relationship between zinc, cobalt and mortality was also observed. Furthermore, a significant overall effect of mixtures of trace elements on all-cause mortality was identified, especially when the mixture was at the 60th percentile or lower.

Conclusion

The association of multiple trace elements with all-cause mortality was identified in this study. It is recommended that healthcare providers and relevant public health agencies should strengthen the surveillance and management of trace elements. Emphasis should be placed on monitoring the sources of trace elements such as the body, food, and environment. More population studies and animal experiments should be conducted to identify the underlying mechanisms.

Association between urinary cadmium level and subclinical myocardial injury in the general population without cardiovascular disease aged ≥ 50 years

Cadmium (Cd) is a toxic heavy metal linked to an increased risk of cardiovascular disease (CVD). But the relationship between urinary Cd (U-Cd) and electrocardiographic subclinical myocardial injury (SC-MI) in older people is unclear. This study evaluated the connection between U-Cd and SC-MI in people who did not have CVD. The study involved 4269 participants from the National Health and Nutrition Examination Survey III(NHANES III) aged ≥ 50 years and had no history of CVD. The relationship between U-Cd and cardiac infarction/injury score (CIIS) was assessed by multivariable linear regression. Whether U-Cd and SC-MI were correlated was determined by multivariate logistic regression, restricted cubic spline, and subgroup analysis. There was a significant association between U-Cd and CIIS (β, 1.04, 95% confidence interval (CI): 0.39-1.69; P = 0.003) in the highest quartile and fully adjusted model. After adjusting for relevant confounders, multivariable logistic regression showed that participants in the highest quartile of U-Cd had a greater chance of having SC-MI than those in the first ( OR (95% CI), 1.37(1.13,1.66), P for trend = 0.003), and this relationship was especially strong among hypertensive participants. And a positive linear correlation between U-Cd and the prevalence of SC-MI was shown by restricted cubic spline analysis. U-Cd may be a novel risk element for SC-MI because it is independently and linearly linked to CIIS and SC-MI.

Multiple metal exposure and metabolic syndrome in elderly individuals: A case-control study in an active mining district, Northwest China

The prevalence of metabolic syndrome (MetS) is increasing at an alarming rate worldwide, particularly among elderly individuals. Exposure to various metals has been linked to the development of MetS. However, limited studies have focused attention on the elderly population living in active mining districts. Participants with MetS (N = 292) were matched for age (±2 years old) and sex with a healthy subject (N = 292). We measured the serum levels of 14 metals in older people aged 65-85 years. Conditional logistic regression, restricted cubic spline model, multiple linear regression, and Bayesian Kernel Machine Regression (BKMR) were applied to estimate potential associations between multiple metals and the risk of MetS. Serum levels of Sb and Fe were significantly higher than the controls (0.58 μg/L vs 0.46 μg/L, 2167 μg/L vs 2042 μg/L, p < 0.05), while Mg was significantly lower (20035 μg/L vs 20,394 μg/L, p < 0.05). An increased risk of MetS was associated with higher serum Sb levels (adjusted odds ratio (OR) = 1.61 for the highest tertile vs. the lowest tertile, 95% CI = 1.08-2.40, p-trend = 0.018) and serum Fe levels (adjusted OR = 1.55 for the highest tertile, 95% CI = 1.04-2.33, p-trend = 0.032). Higher Mg levels in serum may have potential protective effects on the development of MetS (adjusted OR = 0.61 for the highest tertile, 95% CI = 0.41-0.91, p-trend = 0.013). A joint exposure analysis by the BKMR model revealed that the mixture of 12 metals (except Tl and Cd) was associated with increased risk of MetS. Our results indicated that exposure to Sb and Fe might increase the risk of MetS in an elderly population living in mining-intensive areas. Further work is needed to confirm the protective effect of Mg on MetS.

Urinary Levels of 14 Metal Elements in General Population: A Region-Based Exploratory Study in China

Metal pollution may lead to a variety of diseases; for this reason, it has become a matter of public concern worldwide. However, it is necessary to use biomonitoring approaches to assess the risks posed to human health by metals. In this study, the concentrations of 14 metal elements in 181 urine samples obtained from the general population of Gansu Province, China, were analyzed using inductively coupled plasma mass spectrometry. Eleven out of fourteen target elements had detection frequencies above 85%, namely, Cr, Ni, As, Se, Cd, Al, Fe, Cu and Rb. The concentrations of most metal elements in the urine of our subjects corresponded to the medium levels of subjects in other regional studies. Gender exerted a significant influence (p < 0.05) on the concentrations of Tl, Rb and Zn. The concentrations of Ni, As, Pb, Sr, Tl, Zn, Cu and Se showed significant differences among different age groups and the age-related concentration trends varied among these elements. There were significant differences in the urine concentrations of Zn and Sr between those subjects in the group who were frequently exposed to soil (exposed soil > 20 min/day) and those in the group who were not, indicating that people in regular contact with soil may be more exposed to metals. This study provides useful information for evaluating the levels of metal exposure among general populations.

Associations between multiple urinary metals and the risk of hypertension in community-dwelling older adults

Although metal exposure has been associated with hypertension, the conclusions remain controversial, and studies investigating the predictive effect of multiple metals on hypertension are limited. In this study, we aimed to evaluate the nonlinear dose-response relationship between a single urinary metal and the risk of hypertension, and to assess the predictive effect of multiple urinary metals on hypertension. Of the Yinchuan community-dwelling elderly cohort launched in 2020, 3,733 participants (803 with hypertension and 2,930 without hypertension) were analysed in this study, and the concentrations of 13 metal elements in urine were measured. We found that urinary vanadium (odds ratio (OR): 1.16, 95% confidence interval [CI]: 1.08-1.25), molybdenum (OR: 1.08, 95% CI: 1.01-1.16), and tellurium (OR: 1.14, 95% CI: 1.06-1.22) were associated with higher risk of hypertension, whereas iron (OR: 0.92, 95% CI: 0.85-0.98) and strontium (0.92, 95% CI: 0.85-0.99) were significantly associated with lower risk of hypertension. Restricted cubic splines analysis was conducted in patients with iron concentrations of ≥ 15.48 μg/g and ≤ 399.41 μg/g and a strontium concentration of ≤ 69.41 μg/g, results showed that the risk of hypertension decreased gradually as the urinary concentrations of these metals increased. With an increase in the vanadium concentration in urine, the risk of hypertension gradually increased. In patients with a molybdenum concentration of ≥ 56.82 μg/g and a tellurium concentration of ≥ 21.98 μg/g, the risk of hypertension gradually decreased as the urinary concentrations of these metals increased. Predictive scores based on the 13 metallic elements were significantly associated with a higher risk of hypertension (OR: 1.34 (95% CI: 1.25-1.45). After additionally including urinary metal concentrations as a parameter variable in the traditional hypertension risk assessment model, integrated discrimination and net reclassification increased by 8.00% (P < 0.001) and 2.41% (P < 0.001), respectively. Urinary vanadium, Mo, and Te concentrations were associated with a higher risk of hypertension, while iron and strontium concentrations were associated with a lower risk of hypertension. Multiple urinary metal concentrations can significantly improve the predictive ability of traditional hypertension risk-assessment models.

Associations of blood lead, cadmium, and mercury with resistant hypertension among adults in NHANES, 1999-2018

BACKGROUND

Resistant hypertension (RHTN), a clinically complex condition with profound health implications, necessitates considerable time and allocation of medical resources for effective management. Unraveling the environmental risk factors associated with RHTN may shed light on future interventional targets aimed at reducing its incidence. Exposure to heavy metal has been linked to an increased risk of hypertension, while the relationship with RHTN remains poorly understood.

METHODS

Using the 1999-2018 National Health and Nutrition Examination Survey (NHANES) data, we examined the association of blood lead (Pb), cadmium (Cd), and mercury (Hg) with RHTN using a multinomial logistic regression model. The combined effects of the metals and the contribution of each metal were assessed using a weighted quantile sum (WQS) analysis.

RESULTS

A total of 38281 participants were included in the analysis. Compared with no resistant hypertension (NRHTN), per 1 µg/dL increase in blood Pb concentration, the proportion of RHTN increased by 16% [adjusted odds ratio (aOR), 1.16; 95% confidence interval (CI) 1.01-1.32]. When analyzed by quartiles (Q), the aOR [95% CI] for Pd was 1.30[1.01,1.67] (Q4 vs. Q1); there was a significant dose-response relationship (p < 0.05). Likewise, as a continuous variable, each 1 µg/dL increase in blood Cd level was associated with a 13% increase in the proportion of RHTN (aOR: 1.13; 95%CI: [1.00,1.27]); when analyzed as quartile, aOR [95% CI] for Cd were 1.30[1.01,1.69] (Q3 vs. Q1), and 1.35[1.03,1.75] (Q4 vs. Q1); the dose-response relationship was significant (p < 0.05). WQS analysis showed a significant combined effects of Pb, Cd, and Hg on RHTN, with Pb as the highest weight (0.64), followed by Cd (0.25) and Hg (0.11). Stratified analysis indicated that the associations for the two heavy metals were significant for participants who were male, ≼ 60 years old, and with kidney dysfunction.

CONCLUSION

Findings of this study with national data provide new evidence regarding the role of environmental heavy metal exposure in RHTN. The prevention strategies aimed at reducing heavy metal exposure should particularly focus on Americans who are middle-aged, male, and afflicted with kidney dysfunction.

Relationship between Occupational Metal Exposure and Hypertension Risk Based on Conditional Logistic Regression Analysis

Occupational exposure is a significant source of metal contact; previous studies have been limited regarding the effect of occupational metal exposure on the development of hypertension. This study was conducted to assess the levels of exposure of certain metals (chromium (Cr), iron (Fe), manganese (Mn), and nickel (Ni)) in hypertensive and non-hypertensive workers and to assess the relationship between the risk of hypertension and metal exposure level. Our study included 138 hypertensive patients as case groups and 138 non-hypertensive participants as controls. The exposure risk level was divided according to the limit value after collecting and testing the metal dust in the workshop. Considering the influence of single- and poly-metal, single factor analysis and conditional logistic regression analysis of poly-metal were carried out. The results of the model indicated that the incidence of hypertension increased with an increase in Cr exposure level, and the risk of hypertension was 1.85 times higher in the highest exposure than in the lowest exposure (95% CI: 1.20−2.86, p < 0.05). Mn has the same effect as Cr. There was no significant correlation between Fe or Ni and hypertension. Our findings suggested that Cr and Mn exposure in the work environment might increase the risk of hypertension, while no effect of Fe and Ni on blood pressure was found. Prospective study designs in larger populations are needed to confirm our findings.

Individual PM2.5 component exposure model, elevated blood pressure and hypertension in middle-aged and older adults: A nationwide cohort study from 125 cities in China

Recently, elevated blood pressure (BP) and hypertension (HTN) have caused a huge burden of health loss. Previous studies used ambient air pollutants as a proxy for individual exposure, limiting the assessment of its multiple exposure to health effects. For the first time, this study constructed individual PM_2.5 component (SO₄^2-, NO₃^-, NH₄⁺, OM, and BC) exposure model DAG (Directed Acyclic Graph), DAG-oriented generalized linear model and random forest model, and explored the effects of single and multiple exposures to PM_2.5 components on BP at different stages by the generalized linear model (GLM) and Quantile g-Computation (QgC) model based on a large cohort study in China. We defined BP in four stages according to the 2017 ACC/AHA guidelines. After excluding the lack of key information, the cohort analyses ultimately included 9031 participants. Our results showed that the individual PM_2.5 component exposure model had good efficacy. Single or multiple exposure to PM_2.5 components had significant positive effects on normal BP to elevated BP and elevated BP to stage 1 HTN. In addition, males, the elderly and urban residents were more sensitive to PM_2.5 components. This study provided implications for environmental exposure assessment and control of particulate pollution in the future.

Combined exposure to multiple metals on cardiovascular disease in NHANES under five statistical models

BACKGROUND

It is well-documented that heavy metals are associated with cardiovascular disease (CVD). However, there is few studies exploring effect of metal mixture on CVD. Therefore, the primary objective of present study was to investigate the joint effect of heavy metals on CVD and to identify the most influential metals in the mixture.

METHODS

Original data for study subjects were obtained from the National Health and Nutrition Examination Survey. In this study, adults with complete data on 12 kinds of urinary metals (antimony, arsenic, barium, cadmium, cobalt, cesium, molybdenum, mercury, lead, thallium, tungsten, and uranium), cardiovascular disease, and core covariates were enrolled. We applied five different statistical strategies to examine the CVD risk with metal exposure, including multivariate logistic regression, adaptive elastic net combined with Environmental Risk Score, Quantile g-computation, Weighted Quantile Sum regression, and Bayesian kernel machine regression.

RESULTS

Higher levels of cadmium, tungsten, cobalt, and antimony were significantly associated with Increased risk of CVD when covariates were adjusted for multivariate logistic regression. The results from multi-pollutant strategies all indicated that metal mixture was positively associated with the risk of CVD. Based on the results of multiple statistical strategies, it was determined that cadmium, tungsten, cobalt, and antimony exhibited the strongest positive correlations, whereas barium, lead, molybdenum, and thallium were most associated with negative correlations.

CONCLUSION

Overall, our study demonstrates that exposure to heavy metal mixture is linked to a higher risk of CVD. Meanwhile, this association may be driven primarily by cadmium, tungsten, cobalt, and antimony. Further prospective studies are warranted to validate or refute our primary findings as well as to identify other important heavy metals linked with CVD.

Co-exposure to priority-controlled metals mixture and blood pressure in Chinese children from two panel studies

Metals may affect adversely cardiovascular system, but epidemiological evidence on the associations of priority-controlled metals including antimony (Sb), arsenic (As), cadmium, lead, and thallium with children's blood pressure (BP) was scarce and inconsistent. We conducted two panel studies with 3 surveys across 3 seasons among 144 and 142 children aged 4-12 years in Guangzhou and Weinan, respectively. During each seasonal survey, urine samples were collected for 4 consecutive days and BP was measured on the 4th day. We obtained 786 BP values and urinary metals measurements at least once within 4 days, while 773, 596, 612, and 754 urinary metals measurements were effective on the health examination day (Lag 0), and the 1^st, 2^nd, and 3^rd day preceding BP measurement (Lag 1, lag 2 and lag 3), respectively. We used linear mixed-effect models, generalized estimating equations and multiple informant models to assess the associations of individual metal at each lag day and accumulated lag day (4 days averaged, lag 0-3) with BP and hypertension, and Bayesian Kernel Machine Regression to evaluate the relations of metals mixture at lag 0-3 and BP outcomes. We found Sb was positively and consistently related to systolic BP (SBP), mean arterial pressure (MAP), and odds of having hypertension within 4 days, which were the strongest at lag 0 and declined over time. And such relationships at lag 0-3 showed in a dose-response manner. Meanwhile, Sb was the only contributor to the relations of mixture with SBP, MAP, and odds of having hypertension. Also, synergistic interaction between Sb and As was significant. In addition, modification effect of passive smoking status on the association of Sb and SBP was more evident in passive smokers. Accordingly, urinary Sb was consistently and dose-responsively associated with increased BP and hypertension, of which Sb was the major contributor among children.