Cadmium exposure as measured in blood in relation to macrophage density in symptomatic atherosclerotic plaques from human carotid artery

Cadmium contributes to atherosclerosis by affecting macrophage polarization

Chronic cadmium (Cd) exposure contributes to the progression of atherosclerosis, but the direct role of Cd and its mechanisms in atherosclerosis remains incompletely understood. Atherosclerosis is a chronic inflammatory disease promoting macrophage polarization to M1 phenotype and producing pro-inflammations that are vital in regulating the inflammatory response. Herein, through a case-control study, we found that Cd exposure may promote the occurrence of carotid plaque via inflammation, where interleukin-6 (IL-6) may play an important role. We also combined in vivo and in vitro experiments to explore the underlying mechanism of Cd-promoted plaque formation and the production of IL-6. With or without cadmium chloride (CdCl₂) fed ApoE^-/- mouse and treated RAW264.7 cells, we found Cd accumulated in the aortas which significantly increased the plaque area in atherosclerotic mice, macrophage accumulation, and lipid accumulation, and Cd promoted M1 phenotype macrophage polarization reflected by the increased expression of CD86 which produced tumor necrosis factor-α (TNF-α) and IL-6. However, the influences on M2 phenotype and anti-inflammatory cytokines interleukin-4 (IL-4) and interferon-γ (IFN-γ) were non-significant. Moreover, we found that JAK2/STAT3 pathway was greatly activated in the plaques and CdCl₂-treated macrophages. The inhibition of JAK2/STAT3 substantially reversed the Cd-stimulated macrophage M1 phenotype macrophage polarization and the expression of pro-inflammatory cytokines including TNF-α and IL-6. Altogether, Cd intensifies atherosclerosis by modulating macrophage polarization via JAK2/STAT3 to up-regulated the expression of IL-6.

Environmental Contaminants Acting as Endocrine Disruptors Modulate Atherogenic Processes: New Risk Factors for Cardiovascular Diseases in Women?

The number of aged individuals is increasing worldwide, rendering essential the comprehension of pathophysiological mechanisms of age-related alterations, which could facilitate the development of interventions contributing to “successful aging” and improving quality of life. Cardiovascular diseases (CVD) include pathologies affecting the heart or blood vessels, such as hypertension, peripheral artery disease and coronary heart disease. Indeed, age-associated modifications in body composition, hormonal, nutritional and metabolic factors, as well as a decline in physical activity are all involved in the increased risk of developing atherogenic alterations that raise the risk of CVD development. Several factors have been reported to play a role in the alterations observed in muscle and endothelial cells and that lead to increased CVD, such as genetic pattern, smoking and unhealthy lifestyle. Moreover, a difference in the risk of these diseases in women and men has been reported. Interestingly, in the past decades attention has been focused on a potential role of several pollutants that disrupt human health by interfering with hormonal pathways, and more specifically in non-communicable diseases such as obesity, diabetes and CVD. This review will focus on the potential alteration induced by Endocrine Disruptors (Eds) in the attempt to characterize a potential role in the cellular and molecular mechanisms involved in the atheromatous degeneration process and CVD progression.

Review of cadmium exposure and smoking-independent effects on atherosclerotic cardiovascular disease in the general population

BACKGROUND

Exposure to cadmium (Cd) via food and smoking is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Blood and urine levels of Cd are established biomarkers of exposure.

OBJECTIVES

To review (1) the smoking-independent associations between Cd exposure and ASCVD, including the possible presence of a nonlinear dose-response relationship with Cd exposure and (2) the causal effects of Cd exposure on different stages of atherosclerosis.

METHODS

Narrative review.

RESULTS

Cd confers increased risk of ASCVD and asymptomatic atherosclerosis in the carotid and coronary arteries above B-Cd >0.5 μg/L or U-Cd >0.5 μg/g creatinine, but it has not been shown below a threshold of these exposure levels. Adjustment for smoking does not exclude the possibility of residual confounding, but several studies in never-smoking cohorts have shown associations between Cd and ASCVD, and experimental studies have demonstrated pro-atherosclerotic effects of Cd. Cd accumulates in arterial walls and atherosclerotic plaques, reaching levels shown to have proatherosclerotic effects. Suggested early effects are increased subendothelial retention of atherogenic lipoproteins, which become oxidized, and endothelial dysfunction and damage with increased permeability for monocytes, which in the intima turn to macrophages and then to foam cells. Later, Cd may contribute to plaque rupture and erosion by endothelial apoptosis and degradation of the fibrous cap. Finally, by having prothrombotic and antifibrinolytic effects, the CVD risk may be further increased.

CONCLUSIONS

There is strong evidence that Cd causes ASCVD above a suggested exposure level via mechanisms in early as well as the late stages of atherosclerotic disease.

Receptor-Interacting Protein Kinase 3 Inhibition Prevents Cadmium-Mediated Macrophage Polarization and Subsequent Atherosclerosis via Maintaining Mitochondrial Homeostasis

Chronic cadmium (Cd) exposure contributes to the progression of cardiovascular disease (CVD), especially atherosclerosis (AS), but the underlying mechanism is unclear. Since mitochondrial homeostasis is emerging as a core player in the development of CVD, it might serve as a potential mechanism linking Cd exposure and AS. In this study, we aimed to investigate Cd-mediated AS through macrophage polarization and know the mechanisms of Cd-caused mitochondrial homeostasis imbalance. In vitro, flow cytometry shows that Cd exposure promotes M1-type polarization of macrophages, manifested as the increasing expressions of nuclear Factor kappa-light-chain-enhancer of activated B (NF-kB) and NLR family pyrin domain containing 3 (NLRP3). Mitochondrial homeostasis tests revealed that decreasing mitochondrial membrane potential and mitophage, increasing the mitochondrial superoxide (mROS), and mitochondrial fission are involved in the Cd-induced macrophage polarization. The upregulated expressions of receptor-interacting protein kinase 3 (RIPK3) and pseudokinase-mixed lineage kinase domain-like protein (p-MLKL) were observed. Knocking out RIPK3, followed by decreasing the expression of p-MLKL, improves the mitochondrial homeostasis imbalance which effectively reverses macrophage polarization. In vivo, the oil red O staining showed that Cd with higher blood significantly aggravates AS. Besides, M1-type polarization of macrophages and mitochondrial homeostasis imbalance were observed in the aortic roots of the mice through immunofluorescence and western blot. Knocking out RIPK3 restored the changes above. Finally, the administered N-acetyl cysteine (NAC) or mitochondrial division inhibitor-1 (Mdivi-1), which decreased the mROS or mitochondrial fission, inhibited the expressions of RIPK3 and p-MLKL, attenuating AS and macrophage M1-type polarization in the Cd-treated group. Consequently, the Cd exposure activated the RIPK3 pathway and impaired the mitochondrial homeostasis, resulting in pro-inflammatory macrophage polarization and subsequent AS. Knocking out RIPK3 provided a potential therapeutic target for Cd-caused macrophage polarization and subsequent AS.

Immunomodulation by heavy metals as a contributing factor to inflammatory diseases and autoimmune reactions: Cadmium as an example

Cadmium (Cd) represents a unique hazard because of the long biological half-life in humans (20-30 years). This metal accumulates in organs causing a continuum of responses, with organ disease/failure as extreme outcome. Some of the cellular and molecular alterations in target tissues can be related to immune-modulating potential of Cd. This metal may cause adverse responses in which components of the immune system function as both mediators and effectors of Cd tissue toxicity, which, in combination with Cd-induced alterations in homeostatic reparative activities may contribute to tissue dysfunction. In this work, current knowledge concerning inflammatory/autoimmune disease manifestations found to be related with cadmium exposure are summarized. Along with epidemiological evidence, animal and in vitro data are presented, with focus on cellular and molecular immune mechanisms potentially relevant for the disease susceptibility, disease promotion, or facilitating development of pre-existing pathologies.

The endocrine disruptor cadmium: a new player in the pathophysiology of metabolic diseases

Cadmium (Cd), a highly toxic heavy metal, is found in soil, environment and contaminated water and food. Moreover, Cd is used in various industrial activities, such as electroplating, batteries production, fertilizers, while an important non-occupational source is represented by cigarette smoking, as Cd deposits in tobacco leaves. Since many years it is clear a strong correlation between Cd body accumulation and incidence of many diseases. Indeed, acute exposure to Cd can cause inflammation and affect many organs such as kidneys and liver. Furthermore, the attention has focused on its activity as environmental pollutant and endocrine disruptor able to interfere with metabolic and energy balance of living beings. Both in vitro and in vivo experiments have demonstrated that the Cd-exposure is related to metabolic diseases such as obesity, diabetes and osteoporosis even if human studies are still controversial. Recent data show that Cd-exposure is associated with atherosclerosis, hypertension and endothelial damage that are responsible for cardiovascular diseases. Due to the large environmental diffusion of Cd, in this review, we summarize the current knowledge concerning the role of Cd in the incidence of metabolic and cardiovascular diseases.

Cadmium Exposure and Coronary Artery Atherosclerosis: A Cross-Sectional Population-Based Study of Swedish Middle-Aged Adults

BACKGROUND

The general population is ubiquitously exposed to the toxic metal cadmium through the diet and smoking. Cadmium exposure is associated with increased morbidity and mortality in myocardial infarction and stroke. Atherosclerosis is the main underlying mechanism of myocardial infarction. However, associations between cadmium and coronary artery atherosclerosis have not been examined.

OBJECTIVES

Our study sought to examine the hypothesis that blood cadmium (B-Cd) is positively associated with coronary artery calcification, as a measure of coronary artery atherosclerosis in the population-based Swedish SCAPIS study.

METHODS

Our analysis included 5,627 individuals (51% women), age 50-64 y, enrolled from 2013 to 2018. The coronary artery calcium score (CACS) was obtained from computed tomography. Blood cadmium was determined by inductively coupled plasma mass spectrometry (ICP-MS). Associations between B-Cd and coronary artery calcium score (CACS Agatston score) were evaluated using prevalence ratios (PRs) in models adjusted for sex, age, smoking, hypertension, diabetes, low-density cholesterol/high-density cholesterol ratio, and family history.

RESULTS

The median B-Cd concentration was 0.24μg/L. The prevalence of positive coronary artery calcium (CACS>0) was 41% and the prevalence of CACS≥100 was 13%. Relative to the lowest quartile (Q) of B-Cd (<0.16μg/L), the highest quartile (median 0.63μg/L) was associated with a small but significant increase in CACS>0 (PR 1.1; 95% CI: 1.0, 1.3), and a greater relative increase in CACS≥100 (PR 1.6; 95% CI: 1.3, 2.0). When restricted to 2,446 never-smokers, corresponding PRs were 1.1 (95% CI 0.9, 1.3) for CACS>0 (63 cases in Q4) and 1.7 (95% CI 1.1, 2.7) for CACS≥100 (17 cases in Q4).

DISCUSSION

Blood cadmium in the highest quartile was associated with CACS in a general population sample with low to moderate cadmium exposure. This supports the hypothesis that atherosclerosis is an important mechanism underlying the associations between cadmium and incident cardiovascular disease. The findings suggest that public health measures to reduce cadmium exposure are warranted. https://doi.org/10.1289/EHP8523.

An updated systematic review on the association between Cd exposure, blood pressure and hypertension

BACKGROUND

Since the first report by Perry et al. (1955), most studies affirmed the hypertensive effects of cadmium (Cd) in humans. Nonetheless, conclusions between studies remain inconsistent.

OBJECTIVE

The aim of this study was to reevaluate the evidence for a potential relationship between Cd exposure and altered blood pressure and/or hypertension, focusing on studies published between January 2010 and March 2020.

METHODS

We reviewed all observational studies from database searches (PubMed and SCOPUS) on Cd exposure and blood pressure or hypertension. We extracted information from studies that provided sufficient data on population characteristics, smoking status, exposure, outcomes, and design.

RESULTS

Thirty-eight studies met our inclusion criteria; of those, twenty-nine were cross sectional, three case control, five cohort and one interventional study. Blood or urinary Cd levels were the most commonly used biomarkers.

CONCLUSIONS

A positive association between blood Cd levels and blood pressure and/or hypertension was identified in numerous studies at different settings. Limited number of representative population-based studies of never-smokers was observed, which may have confounded our conclusions. The association between urinary Cd and blood pressure and/or hypertension remains uncertain due to conflicting results, including inverse relationships with lack of strong mechanistic support. We point to the urgent need for additional longitudinal studies to confirm our findings.

Linking molecular targets of Cd in the bloodstream to organ-based adverse health effects

The chronic exposure of human populations to toxic metals remains a global public health concern. Although chronic Cd exposure is linked to kidney damage, osteoporosis and cancer, the underlying biomolecular mechanisms remain incompletely understood. Since other diseases could also be causally linked to chronic Cd exposure, a systems toxicology-based approach is needed to gain new insight into the underlying exposure-disease relationship. This approach requires one to integrate the cascade of dynamic bioinorganic chemistry events that unfold in the bloodstream after Cd enters with toxicological events that unfold in target organs over time. To this end, we have conducted a systematic literature search to identify all molecular targets of Cd in plasma and in red blood cells (RBCs). Based on this information it is impossible to describe the metabolism of Cd and the toxicological relevance of it binding to molecular targets in/on RBCs is elusive. Perhaps most importantly, the role that peptides, amino acids and inorganic ions, including HCO₃^-, Cl^- and HSeO₃^- play in terms of mediating the translocation of Cd to target organs and its detoxification is poorly understood. Causally linking human exposure to this metal with diseases requires a much better integration of the bioinorganic chemistry of Cd that unfolds in the bloodstream with target organs. This from a public health point of view important goal will require collaborations between scientists from different disciplines to untangle the complex mechanisms which causally link Cd exposure to disease.

Association between Blood Heavy Metal Levels and Predicted 10-Year Risk for A First Atherosclerosis Cardiovascular Disease in the General Korean Population

Background: Atherosclerotic cardiovascular disease (ASCVD) is a preventable type of disease, thus, specifying factors that increase the occurrence of this type of disease is needed. Heavy metals such as cadmium (Cd), lead (Pb), and mercury (Hg) have been suggested as possible factors influencing the development of cardiovascular disease. We aimed to link blood heavy metal levels (Cd, Pb, Hg) with 10-year ASCVD risk scores. Methods: A population of 993 men and 1431 women who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) were included. The 2013 American College of Cardiology/American Heart Association (ACC/AHA) pooled cohort equations risk prediction model and Korean Risk Prediction Model (KRPM) were used as means for risk prediction. Following multivariate adjustment; blood Cd; Pb; and Hg levels were divided into quartiles for analysis using linear trends estimation and multiple regression models. Results: There was an overall positive trend between blood Cd, Pb, and Hg levels and 10-year ASCVD risk scores; KRPM risk score increasing by quartile for blood Cd (men p < 0.0001, women p = 0.0024), Pb (men p = 0.0097, women p = 0.0330), Hg (men p = 0.0096, women p = 0.0030) rates and pooled cohort equations risk score increasing by quartile for Cd (men p < 0.0001, women p = 0.0034) and Hg (men p = 0.0099, women p = 0.0010) with linear trends. Urban population showed a stronger relationship between blood Cd, Pb, and Hg levels and 10-year ASCVD risk score especially among men with multiple regression analysis. Conclusion: Blood Cd, Pb, and Hg levels are associated with ASCVD risk. Thus, they should be considered while developing preventive measures for ASCVD.

Smoking-induced risk of future cardiovascular disease is partly mediated by cadmium in tobacco: Malmö Diet and Cancer Cohort Study

BACKGROUND

Smoking is a strong risk factor for cardiovascular disease (CVD) and causes exposure to cadmium, which is a pro-atherosclerotic metal. Cadmium exposure has also been shown to increase the risk of CVD, even after adjustment for smoking. Our hypothesis was that part of the risk of CVD in smokers may be mediated by cadmium exposure from tobacco smoke. We examined this hypothesis in a mediation analysis, trying to assess how much of the smoking-induced CVD risk could be explained via cadmium.

METHODS

We used prospective data on CVD (incidence and mortality) in a Swedish population-based cohort of 4304 middle-aged men and women (the Malmö Diet and Cancer Study). Blood cadmium was analyzed in base-line samples from 1991, and clinical events were followed up for 16-19 years based on registry data. Mediation analysis was conducted to evaluate the indirect effect (via cadmium) of smoking on CVD. Survival was analyzed by the accelerated failure time (AFT) model and the Aalen additive hazard model.

RESULTS

The mean blood cadmium level in the study population was 0.43 μg/L (median 0.24 μg/L) and increased with recent and current smoking. As expected, shorter survival time (AFT model) and higher incidence rate (Aalen model) were found in current smokers for all CVD outcomes and this effect seemed to be partly mediated by cadmium. For the sum of acute myocardial infarction, bypass grafts and percutaneous coronary intervention, and death in ischemic heart disease, about half of the increased risk of such events in current smokers was mediated via cadmium, with similar results for the AFT and Aalen models.

CONCLUSIONS

Cadmium plays an important role in smoking-induced CVDs. This provides evidence for mechanisms and is of importance for both individuals and policy makers.

Cadmium exposure alters steroid receptors and proinflammatory cytokine levels in endothelial cells in vitro: a potential mechanism of endocrine disruptor atherogenic effect

BACKGROUND

Cadmium (Cd) is a widespread environmental pollutant that causes alterations in human health acting as endocrine disruptor. Recent data suggest that cardiovascular system might be a contamination target tissue, since Cd is found in atheromatic plaques. Thus, the purpose of this study was to evaluate the consequence of Cd exposure of endothelial cells in vitro to evaluate detrimental effect in vascular system by a potential sex-steroid hormone receptor-dependent mechanism(s).

METHODS

To this aim, Human Umbilical Vein Endothelial Cells (HUVECs) were cultured and exposed to several concentrations of cadmium chloride (CdCl₂) for different interval times.

RESULTS

CdCl₂ exposure of HUVECs induced a significant increase of ERβ and Cyp19a1 at both mRNA and protein levels, while a drastic dose-dependent decrease of AR expression level was observed after 24 h of exposure. On the contrary, an increase of PhAR^ser308 as well as a reduction of PhGSK-3β^ser9 and PhAKT^ser473 was detected after 1 h treatment. This effect was consistently reduced by GSK inhibition. Furthermore, CdCl₂ abolished DHT-induced cell proliferation in HUVECs suggesting an antagonist-like effect of Cd on AR-mediated signaling. Remarkable, after 6 h CdCl₂-treatment, a relevant increase in TNF-α, IL-6 and IL-8 mRNA was observed and this effect was blocked by the presence of an ERβ-selective antagonist. Moreover, Cd-induced TxR1 overexpression, likely, correlated with the activation of p38 MAPK/NF-κB pathway.

CONCLUSION

In conclusion, our study demonstrates for the first time that Cd alters sex-steroid hormone receptors level and activity likely affecting intracellular signaling linked to a proinflammatory state in endothelial cells. This alteration might possibly lead to endothelial cell injury and vascular dysfunction and could be a mechanism of gender-specific atherogenic damages induced by endocrine disruptors and, thus, induce atherogenic events with increased risk of cardiovascular diseases in individuals exposed to this endocrine disruptor.

Biomarkers of blood cadmium and incidence of cardiovascular events in non-smokers: results from a population-based proteomics study

BACKGROUND

Cadmium is a toxic metal with multiple adverse health effects, including risk of cardiovascular disease (CVD). The mechanistic link between cadmium and CVD is unclear. Our aim was to examine the associations between blood cadmium (B-Cd) and 88 potential protein biomarkers of CVD.

METHODS

B-Cd and 88 plasma proteins were measured in a community-based prospective cohort, the Malmö Diet and Cancer study. The primary analysis was performed in never smokers (n = 1725). Multiple linear regression was used with adjustments for age and sex, and correction for multiple comparisons using the false discovery rate method. Proteins significantly associated with B-Cd were replicated in long-term former smokers (n = 782). Significant proteins were then studied in relation to incidence of CVD (i.e., coronary events or ischemic stroke) in never smokers.

RESULTS

Fifteen proteins were associated with B-Cd in never smokers. Eight of them were replicated in long-term former smokers. Kidney injury molecule-1, fibroblast growth factor-23 (FGF23), tumor necrosis factor receptor-2, matrix metalloproteinase-12, cathepsin L1, urokinase plasminogen activator receptor, C-C motif chemokine-3 (CCL3), and chemokine (C-X3-C motif) ligand-1 were associated with B-Cd both in never smokers and long-term former smokers. Except for CCL3 and FGF23, these proteins were also significantly associated with incidence of CVD.

CONCLUSIONS

B-Cd in non-smokers was associated with eight potential plasma biomarkers of CVD and kidney injury. The results suggest pathways for the associations between B-Cd and CVD and kidney injury.

Hepatoprotective effect of polyphenols isolated from virgin coconut oil against sub-chronic cadmium hepatotoxicity in rats is associated with improvement in antioxidant defense system

Cadmium (Cd) is a ubiquitous non-essential environmental and industrial toxicant that affects various organs in humans and experimental animals. Robust evidence confirms the contribution of oxidative stress to the pathogenesis of Cd-induced hepatic damage. Potent polyphenols found in virgin coconut oil (VCO) are free radical scavengers that may be beneficial against Cd hepatotoxicity. Thus, we aimed to evaluate the possible protective effect of polyphenols isolated from VCO on Cd-induced hepatotoxicity and oxidative stress in rats. Rats were pretreated with polyphenols isolated from VCO (10, 20, and 50 mg/kg, orally) 2 weeks prior to concurrent Cd administration (5 mg/kg, orally) for 5 weeks. Subsequently, liver damage, hepatic oxidative stress, and histopathological alterations were evaluated. In vitro antioxidant assays (DPPH and FRAP) were carried out on VCO polyphenols. Cadmium induced liver damage demonstrated by significant alterations in serum markers of liver damage, as well as pronounced decrease in albumin and total protein compared to control. Further, Cd remarkably depressed hepatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) content. Hepatic lipid peroxidation was markedly increased as highlighted by malondialdehyde (MDA) content. Sub-chronic administration of VCO polyphenols to Cd-treated rats produced a significant hepatoprotective effect and restored hepatic oxidative stress markers comparable to control. The prominent improvement in histopathology of rat liver confirmed the biochemical findings. The findings suggest potential beneficial effect of VCO polyphenols on Cd-induced hepatotoxicity and oxidative stress in rats; the mechanism underlying this action is associated with improvement in antioxidant defense system.

High Content of Lead Is Associated with the Softness of Drinking Water and Raised Cardiovascular Morbidity: A Review

Daily ingestion of lead (Pb), even through piped drinking water, has long time been an important issue of concern, attracting for decades research in environmental science and toxicology, and again comes to prominence because of recent high-profile cases of exposure of populations in several countries to Pb-contaminated water. Numerous studies have reported an association between Pb in water and the risk of cardiovascular pathologies. Low levels of magnesium and calcium, i.e., low degree of hardness of the drinking water, may accentuate Pb leaching from water pipes and furthermore increase Pb absorption. This review evaluates the evidence for an association between Pb exposure from drinking water and cardiovascular end points in human populations.

Cadmium and atherosclerosis: A review of toxicological mechanisms and a meta-analysis of epidemiologic studies

Cadmium has been proposed to be the one of the factors of atherosclerosis development, although the existing data are still controversial. The primary objective of the present study is the review and the meta-analysis of studies demonstrating the association between Cd exposure and atherosclerosis as well as review of the potential mechanisms of such association. We performed a systematic search in the PubMed-Medline database using the MeSH terms cadmium, cardiovascular disease, atherosclerosis, coronary artery disease, myocardial infarction, stroke, mortality and humans up through December 20, 2017. Elevated urinary Cd levels were associated with increased mortality for cardiovascular disease (HR = 1.34, 95% CI: 1.07-1.67) as well as elevated blood Cd levels (HR = 1.78, 95% CI: 1.24-2.56). Analysis restricted to never smokers showed similar, though more imprecise, results. Consistently, we also observed an association between Cd exposure markers (blood and urine) and coronary heart disease, stroke, and peripheral artery disease. Moreover, Cd exposure was associated with atherogenic changes in lipid profile. High Cd exposure was associated with higher TC levels (OR = 1.48, 95% CI: 1.10-2.01), higher LDL-C levels (OR = 1.31, 95% CI 0.99-1.73) and lower HDL-C levels (OR = 1.96, 95% CI: 1.09-3.55). The mechanisms of atherogenic effect of cadmium may involve oxidative stress, inflammation, endothelial dysfunction, enhanced lipid synthesis, up-regulation of adhesion molecules, prostanoid dysbalance, as well as altered glycosaminoglycan synthesis.

Cadmium, Carotid Atherosclerosis, and Incidence of Ischemic Stroke

Background

Exposure to cadmium has been associated with carotid plaques, inflammation in carotid plaques, and increased risk of ischemic stroke. This study examined the separate and interacting effects of blood cadmium levels and carotid plaques on the risk of incident ischemic stroke.

Methods and Results

Cadmium levels were measured in 4156 subjects (39.2% men; mean±SD age 57.3±5.9 years) without history of stroke, from the Malmö Diet and Cancer cohort. The right carotid artery was examined using B‐mode ultrasound examination at baseline. Incidence of ischemic stroke was monitored over a mean follow‐up of 16.7 years. Carotid plaque was present in 34.5% of participants. Cadmium was significantly higher in subjects with plaque (mean±SD: 0.53±0.58 μg/L versus 0.42±0.49 μg/L; P<0.001). A total of 221 subjects had ischemic stroke during the follow‐up. Incidence of ischemic stroke was associated both with carotid plaque (hazard ratio 1.44, 95% confidence interval, 1.09–1.90, P=0.009) and cadmium (hazard ratio for quartile [Q] 4 versus Q1–3: 1.95, confidence interval, 1.33–2.85, P=0.001), after adjustment for risk factors. There was a significant interaction between cadmium and plaque with respect to risk of ischemic stroke (P=0.011). Adjusted for risk factors, subjects with plaque and cadmium in Q4 had a hazard ratio of 2.88 (confidence interval, 1.79–4.63) for ischemic stroke, compared with those without plaque and cadmium in Q1 to Q3.

Conclusions

Cadmium was associated with incidence of ischemic stroke, both independently and in synergistic interaction with carotid plaques. This supports the hypothesis that cadmium promotes vulnerability of carotid plaques, thereby increasing the risk of rupture and ischemic stroke.

Association between cadmium exposure and diabetes mellitus risk: a prisma-compliant systematic review and meta-analysis

Cadmium (Cd) is a pollutant with multiple adverse health effects: cancer, renal dysfunction, osteoporosis and fracture, and cardiovascular disease. Several population-based studies found an association between Cd and diabetes mellitus (DM), but this association is inconsistent with other research. We conducted meta-analysis to examine relationship between urinary/blood Cd exposure and DM risk. Pertinent studies were identified by searching PubMed and Embase databases, and combined odds ratio (OR) and corresponding 95% confidence interval (CI) were applied to evaluate said association. Meta-analysis showed that high U-Cd exposure is not correlated with DM risk (OR = 1.19; 95% CI = 0.83–1.71), and high B-Cd exposure is also not associated with increased risk of DM (OR = 1.16; 95% CI = 0.84-1.62) in the general population. Subgroup and sensitivity analysis proved similar results, with little evidence of publication bias. This meta-analysis suggests that high U-Cd/B-Cd exposure may not be risk factor for DM in general populations. However, large prospective studies are needed to confirm this finding.

Cadmium exposure is associated with soluble urokinase plasminogen activator receptor, a circulating marker of inflammation and future cardiovascular disease

BACKGROUND

Diet and smoking are the main sources of cadmium exposure in the general population. Cadmium increases the risk of cardiovascular diseases, and experimental studies show that it induces inflammation. Blood cadmium levels are associated with macrophages in human atherosclerotic plaques. Soluble urokinase-type plasminogen activator receptor (suPAR) is an emerging biomarker for cardiovascular events related to inflammation and atherosclerotic plaques. The aim was to examine whether blood cadmium levels are associated with circulating suPAR and other markers of inflammation.

METHODS

A population sample of 4648 Swedish middle-aged women and men was examined cross-sectionally in 1991-1994. Plasma suPAR was assessed by ELISA, leukocytes were measured by standard methods, and blood cadmium was analysed by inductively coupled plasma mass spectrometry. Prevalent cardiovascular disease, ultrasound-assessed carotid plaque occurrence, and several possible confounding factors were recorded.

RESULTS

After full adjustment for risk factors and confounding variables, a 3-fold increase in blood cadmium was associated with an 10.9% increase in suPAR concentration (p<0.001). In never-smokers, a 3-fold increase in blood cadmium was associated with a 3.7% increase in suPAR concentration (p<0.01) after full adjustment. Blood cadmium was not associated with C-reactive protein, white blood cell count and Lp-PLA2 but with neutrophil/lymphocyte ratio in one of two statistical models.

CONCLUSIONS

Exposure to cadmium was associated with increased plasma suPAR in the general population, independently of smoking and cardiovascular disease. These results imply that cadmium is a possible cause for raised levels of this inflammatory marker.