Circulating cadmium concentration and risk of aortic aneurysms: A nested case-control study within the Malmö Diet and Cancer cohort

Disturbed Ratios between Essential and Toxic Trace Elements as Potential Biomarkers of Acute Ischemic Stroke

Background: Cadmium (Cd) and lead (Pb) are known to be two of the metal contaminants that pose the greatest potential threat to human health. The purpose of this research study was to compare the levels of toxic metals (Cd, Pb) in patients with acute ischemic stroke (AIS), with a control group in Podlaskie Voivodeship, Poland. The study also aimed to assess the correlations between toxic metals and clinical data in AIS patients, and to assess the potential effect of smoking. Materials and methods: The levels of mineral components in the collected blood samples were assessed by means of atomic absorption spectrometry (AAS). Results: The Cd blood concentration was significantly higher in AIS patients as compared to the control group. We found that the molar ratios of Cd/Zn and Cd/Pb were significantly higher (p < 0.001; p < 0.001, respectively), when the molar ratios of Se/Pb, Se/Cd, and Cu/Cd were significantly lower (p = 0.01; p < 0.001; p < 0.001, respectively), in AIS patients as compared to control subjects. However, there were no considerable fluctuations in relation to the blood Pb concentration or molar ratios of Zn/Pb and Cu/Pb between our AIS patients and the control group. We also found that patients with internal carotid artery (ICA) atherosclerosis, particularly those with 20–50% ICA stenosis, had higher concentrations of Cd and Cd/Zn, but lower Cu/Cd and Se/Cd molar ratios. In the course of our analysis, we observed that current smokers among AIS patients had significantly higher blood-Cd concentrations, Cd/Zn and Cd/Pb molar ratios, and hemoglobin levels, but significantly lower HDL-C concentrations, Se/Cd, and Cu/Cd molar ratios. Conclusions: Our research has shown that the disruption of the metal balance plays a crucial role in the pathogenesis of AIS. Furthermore, our results broaden those of previous studies on the exposure to Cd and Pb as risk factors for AIS. Further investigations are necessary to examine the probable mechanisms of Cd and Pb in the onset of ischemic stroke. The Cd/Zn molar ratio may be a useful biomarker of atherosclerosis in AIS patients. An accurate assessment of changes in the molar ratios of essential and toxic trace elements could serve as a valuable indicator of the nutritional status and levels of oxidative stress in AIS patients. It is critical to investigate the potential role of exposure to metal mixtures in AIS, due to its public health implications.

A systematic review of adverse health effects associated with oral cadmium exposure

Scientific data characterizing the adverse health effects associated with dietary cadmium (Cd) exposure were identified in order to make informed decisions about the most appropriate toxicological reference value (TRV) for use in assessing dietary Cd exposure. Several TRVs are available for Cd and regulatory organizations have used epidemiologic studies to derive these reference values; however, risk of bias (RoB) evaluations were not included in the assessments. We performed a systematic review by conducting a thorough literature search (through January 4, 2020). There were 1714 references identified by the search strings and 328 studies identified in regulatory assessments. After applying the specific inclusion and exclusion criteria, 208 studies (Human: 105, Animal: 103) were considered eligible for further review and data extraction. For the epidemiologic and animal studies, the critical effects identified for oral Cd exposure from the eligible studies were a decrease in bone mineral density (BMD) and renal tubular degeneration. A RoB analysis was completed for 49 studies (30 epidemiological and 19 animal) investigating these endpoints. The studies identified through the SR that were considered high quality and low RoB (2 human and 5 animal) can be used to characterize dose-response relationships and inform the derivation of a Cd TRV.

HDL cholesterol: A potential mediator of the association between serum levels of a mixture of metals and the risk of aortic dissection in a Chinese population

Aortic dissection (AD) is a severe cardiovascular disease with a high mortality rate. However, the associations between the serum levels of metals and the risk of AD remain unclear. One hundred twenty-seven patients with AD (type A and B) identified from 2017 to 2019 at the Second Affiliated Hospital of Nanjing Medical University were included; 183 controls that were also included. A logistic regression analysis was performed to determine the associations between serum levels of metals and the risk of AD. Weighted Quantile Sum (WQS) regression and Bayesian Kernel Machine Regression (BKMR) analyses were performed to explore the effects of mixtures of metals on the risk of AD. A linear regression analysis was performed to evaluate the relationships between the serum levels of metals and the white blood cells (WBCs) count and serum lipid levels and blood glucose. We conducted a mediation analysis to explore the contribution rates of WBC counts or serum lipid levels and blood glucose to the association between metal levels and the risk of AD. Exposure to serum levels of Cu (coefficient = 6.33; 95 % CI = 2.52, 10.14; p trend < 0.001) were significantly and positively associated with the risk of AD. In the WQS analysis, Cu (50.3 %), Ni (32.7 %) and Mo (17.1 %) contributed to the AD risk. In the BKMR analysis, Cu and Mo were shown to play important roles in the association with the AD risk. Moreover, serum concentrations of Cu were significantly and inversely associated with HDL-cholesterol levels. HDL-cholesterol levels mediated 7.42 % of the association between serum Cu levels and the prevalence of AD. Our study provided the first evidence that serum levels of mixtures of metals are associated with the AD risk in a Chinese population. Increased concentrations of metals, particularly Cu, may increase the risk of AD by reducing HDL-cholesterol levels.

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.

Diabetes Mellitus Lowers the Risk of Aortic Dissection: a Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to investigate the association between diabetes mellitus and aortic dissection.

METHODS

The PubMed and Embase databases were searched until December 2019 to identify all articles reporting diabetes mellitus and aortic dissection. The pooled odds ratio and 95% confidence interval were calculated using random-effects model.

RESULTS

A total of 14 articles with 15,794 participants, of which 2133 diabetes mellitus patients, were eligible and included in this meta-analysis. The data suggested that diabetes mellitus decreased the risk of aortic dissection. In the subgroup analysis, this association was significant in worldwide studies except for the Chinese cohort and in studies adjusted for confounding factors. The results were stable after sensitivity analysis and no evidence of publication bias was found among studies.

CONCLUSIONS

The result of this meta-analysis indicated that diabetes mellitus was associated with a lower risk of aortic dissection.

Long-term exposure to air pollution and atherosclerosis in the carotid arteries in the Malmö diet and cancer cohort

BACKGROUND

Long-term exposure to air pollution increases the risk of cardiovascular morbidity and mortality, but the mechanisms are not fully known. Current evidence suggests that air pollution exposure contributes to the development of atherosclerosis. There are few studies investigating associations between air pollution and carotid plaques, a well-known precursor of cardiovascular disease.

METHODS

A Swedish population-based cohort (aged 45-64 years at recruitment) was randomly selected from the Malmö Diet and Cancer study between 1991 and 1994, of which 6103 participants underwent ultrasound examination of the right carotid artery to determine carotid plaque presence and carotid intima media thickness (CIMT). Participants were assigned individual residential air pollution exposure (source-specific PM_2.5, PM₁₀, NO_x, BC) at recruitment from Gaussian dispersion models. Logistic and linear regression models, adjusted for potential confounders and cardiovascular risk factors, were used to investigate associations between air pollutants and prevalence of carotid plaques, and CIMT, respectively.

RESULTS

The prevalence of carotid plaques was 35%. The mean levels of PM_2.5 and PM₁₀ at recruitment were 11 and 14 μg/m³, most of which was due to long range transport. The exposure contrast within the cohort was relatively low. PM_2.5 exposure was associated with carotid plaques in a model including age and sex only (OR 1.10 (95% CI 1.01-1.20) per 1 μg/m³), but after adjustment for cardiovascular risk factors and socioeconomic status (SES) the association was weak and not significant (OR 1.05 (95% CI 0.96-1.16) per 1 μg/m³). The pattern was similar for PM₁₀ and NO_x exposure. Associations between air pollutants and plaques were slightly stronger for long-term residents and in younger participants with hypertension. There was no clear linear trend between air pollution exposure and plaque prevalence. Non-significant slightly positive associations were seen between air pollution exposures and CIMT.

CONCLUSIONS

In this large, well-controlled cross-sectional study at low exposure levels we found no significant associations between air pollution exposures and subclinical atherosclerosis in the carotid arteries, after adjusting for cardiovascular risk factors and SES. Further epidemiological studies of air pollution and intermediate outcomes are needed to explain the link between air pollution and cardiovascular events.

Blood cadmium concentration and risk of subarachnoid haemorrhage

BACKGROUND

Cadmium is a toxic metal and exposure is mainly from diet and tobacco smoke. Cadmium is accumulated in blood vessels and may reduce synthesis of procollagen and inhibit proliferation of vascular smooth muscle cells. High blood cadmium has been associated with increased risk of myocardial infarction, stroke and unruptured intracranial aneurysms. We examined whether blood cadmium increase the risk of subarachnoid haemorrhage (SAH).

METHODS

The Malmö Diet and Cancer cohort (n = 28,449) was examined in 1991-1996 and blood samples were taken. Incidence of SAH was followed up to 2014. Cadmium was measured in stored blood samples from incident SAH cases and matched controls (n = 93 vs n = 276) and odds ratio (OR) for SAH was assessed in a nested case control design.

RESULTS

Subjects with cadmium concentration in the highest quartile had increased risk of SAH compared to those in the first quartile (OR: 3.22, 95%CI: 1.67-6.22). However, after adjusting for smoking, results were weakened and non-significant (OR: 1.57, 95%CI: 0.51-4.80).

CONCLUSIONS

Cadmium concentration was associated with increased risk of SAH but this association was largely explained by smoking. Whether cadmium in tobacco may contribute to the vascular pathology and increased risk of SAH in smokers should be further studied.

Healthy diet and fiber intake are associated with decreased risk of incident symptomatic peripheral artery disease – A prospective cohort study

Peripheral artery disease (PAD) is caused by atherosclerosis and associated with an increased risk of leg amputation, cardiovascular disease, and death. A healthy diet has been shown to reduce the risk of cardiovascular events, but relationships between diet, fiber intake, and incidence of PAD are virtually unknown. The aim was to investigate the long-term impact of diet on the development of PAD among 26,010 middle-aged individuals in the prospective Malmö Diet and Cancer study (MDCS). Data on dietary intake were collected through a 7-day food diary combined with a food questionnaire and a 1-hour interview. Adherence to a recommended intake of six dietary components – saturated fat, polyunsaturated fat, fish and shellfish, fiber, fruit and vegetables, and sucrose – was scored (sum 0–6 points) to assess a diet quality index, adjusting for potential confounders. Cox regression analysis was used to estimate associations between diet variables and PAD incidence expressed in hazard ratios (HR) with 95% CI. During a median follow-up of 21.7 years, 1122 participants developed PAD. Diet score was associated with a reduced risk of PAD in multivariable analysis ( p = 0.03). When mutually adjusting for all dietary variables, only adherence to recommended levels of fiber intake was associated with a reduced risk of incident PAD (HR 0.84; 95% CI 0.72–0.99). In this prospective, population-based study including 26,010 participants with over 20 years of follow-up, a healthy diet, especially a high intake of fiber, was associated with a reduced risk of PAD. Primary prevention programs directed against PAD should therefore include a fiber recommendation.

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.

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.

Adherence to diet recommendations and risk of abdominal aortic aneurysm in the Malmö Diet and Cancer Study

The research examining the association between quality of diet and abdominal aortic aneurysm (AAA) is scarce. The aim of the present study was to explore the association between diet quality and development of AAA for middle-aged individuals in the Malmö Diet and Cancer Study (MDCS), a prospective cohort study with baseline data collection carried out between 1991 and 1996. At baseline, the study participants who were eligible for this study (n = 26133) documented their dietary habits in a food diary and questionnaire. Incident AAA cases during an average of 20.7 years of follow-up were identified by using registers. A diet quality index consisting of six components, saturated fat, polyunsaturated fat, fibre, sucrose, fruits and vegetables and fish and shellfish, was used to assess the diet quality. After adjusting for potential confounders, the diet quality index was not associated with incident AAA. However, a tendency of decreased risk was observed among individuals adhering to recommendations for fruit and vegetables compared with non-adherence. When comparing the risk of more extreme intake groups, high intakes of both fruits and vegetables were associated with decreased risk.

Synthetic endeavors on cadmium species bearing glycolate and aromatic chelators with structure-specific biotoxic correlations in vitro

Cadmium is a well-known metallotoxin widespread in the environment and easily reaching cellular targets in lower and higher organisms, including humans. The form(s) of that metal ion through which it interacts with biomolecular targets in a cellular milieu are critical in cell survival. Poised to investigate the structure-specific activity of Cd(II) in a cellular environment and delve into the associated biotoxic processes, binary and ternary systems of that metal ion in the presence of the physiological α-hydroxycarboxylic acid glycolic acid and aromatic (N,N')-binders 2,2'-bipyridine (2,2'-bipy) and 4,4'-bipyridine (4,4'-bipy) were examined synthetically in aqueous media and a pH-specific fashion. The arising new materials [Cd(C₂H₃O₃)₂]_n (1), [Cd(C₂H₃O₃)(C₁₀H₈N₂)(NO₃)]_n·nH₂O (2), and {[Cd(C₂H₃O₃)(C₁₀H₈N₂)(H₂O)](NO₃)}_n·2nH₂O (3) project coordination polymers, which were physicochemically characterized through elemental analysis, FT-IR, NMR, luminescence and X-ray crystallography. The distinct spectroscopic features of 1-3, with luminescence exemplifying distinct behavior (2,3), further corroborated by crystallographic analysis, lend credence to a structure-specific selection of species employed in ensuing in vitro biological studies. The emerging results in two different cell lines (3T3-L1, Saos-2) reveal a concentration-dependent, structure-specific and cell line-specific toxicity profile of Cd(II), reflecting its coordination composition and formulation, rendering it soluble and bioavailable (1,2). Mechanistic information riding on caspase-dependent investigation unravels that metal ion's specific behavior compromising cell survival and integrity. Employment of ethylenediamine tetraacetic acid (EDTA) a) shows efficient sequestration of Cd(II) away from its toxic reactivity denoting the strength of interactions involved, and b) lends credence to further development of appropriately configured organic binders, selectively providing molecular protection from Cd(II) toxicity.