Increased body cadmium burden in Chinese women without smoking and occupational exposure

The association between Day-1 urine cadmium excretion and 30-day mortality in patients with acute myocardial infarction: A multi-institutional cohort study

BACKGROUND

The aim of this study was to investigate the relationship between day-1 urine cadmium excretion and 30-day mortality in patients with acute myocardial infarction (AMI) at two centers.

METHODS

A total of 286 patients (222 males and 64 females) with AMI from Huashan Hospital, Shanghai and Chang Gung Memorial Hospital, Taiwan were enrolled. Basic vital signs, history, laboratory results, and day-1 urine excretion of cadmium (D1UECd) were recorded. Disease severity was assessed during the first hospitalization using Killip score, APACHE II score, and SOFA score. The main endpoint was 30-day mortality.

RESULTS

Among the 286 patients, 218 were from Chung Gung Memorial Hospital and 68 were from Huashan Hospital with an average age of 64.2 years. Forty (14%) patients died within 30 days after AMI. The average 24-h urine cadmium level among the Chung Gung Memorial Hospital cohort was 1.5 ± 2.4 μg compared to 1.7 ± 1.7 μg among Huashan Hospital cohort, both higher than the local populations. A higher D1UECd level was significantly associated with a greater risk of 30-day mortality (odds ratio 1.68, 95% confidence interval 1.30-2.16) after controlling for a number of covariates. The ability of D1UECd to discriminate 30-day mortality was excellent, with a very high area under the curve (87.2%, 95% CI 82.0-92.5%).

CONCLUSION

D1UECd was positively correlated and an independent predictor of 30-day mortality in the enrolled AMI patients. D1UECd may be a simple, objective prognostic scoring system in AMI patients.

Urinary cadmium levels predict mortality of patients with acute heart failure

BACKGROUND

Acute heart failure (AHF) is a serious condition that is associated with increased mortality in critically ill patients. Previous studies indicated that environmental exposure to cadmium increases mortality of general populations. However, the relationship of cadmium exposure and mortality is unclear for AHF patients.

MATERIALS AND METHODS

A total of 153 patients with AHF in intensive care units (ICUs) met the inclusion criteria and were followed up for 6 months. Demographic data, AHF etiology, hematological and biochemical data, and hospital mortality were recorded. The scores of two predictive systems (Sequential Organ Failure Assessment [SOFA], Acute Physiology and Chronic Health Evaluation II [APACHE II]) for mortality in critically ill patients were calculated, and urinary cadmium levels were recorded.

RESULTS

At the end of the follow-up period, the mortality rate was 24.8%. The survivors (n=115) had higher urinary cadmium levels on day 1 (D1UCd) of ICU admission than non-survivors (n=38). A multiple linear regression analysis revealed a positive correlation between D1UCd and acute kidney injury, but a negative correlation between D1UCd and the level of serum albumin. A multivariate Cox analysis indicated that D1UCd was an independent predictor of mortality in AHF patients. For each increment of 1 μg of D1UCd, the hazard ratio for ICU mortality was 1.20 (95% confidence interval [CI]: 1.09-1.32, P<0.001). The area under the receiver operating characteristic curve for D1UCd was 0.84 (95% CI: 0.78-0.91), better than the values for the SOFA and APACHE II systems.

CONCLUSION

The D1UCd may serve as a single predictor of hospital mortality for AHF patients in the ICU. Because of the high mortality and smaller sample size, more investigations are required to confirm these observations and elucidate the underlying mechanisms.

Association between blood cadmium levels and malnutrition in peritoneal dialysis

Background

Malnutrition is associated with an increased risk of cardiovascular death and may cause protein-energy wasting in individuals with chronic kidney disease. A previous study demonstrated that blood cadmium levels (BCLs) were associated with malnutrition in maintenance hemodialysis (MHD) patients. However, the correlation between cadmium exposure and malnutrition remains unclear in chronic peritoneal dialysis (CPD) patients. This study examined the possible adverse effects of environmental cadmium exposure in CPD patients.

Methods

A total of 301 CPD patients were enrolled and divided into 3 study groups based on the following BCL tertiles: low (<0.19 μg/L), middle (0.19–0.39 μg/L), and high (>0.39 μg/L). Demographic, hematological, biochemical, and dialysis-related data were obtained for analysis. The analysis also included values of nutritional and inflammatory markers.

Results

The BCLs of CPD patients were lower than those of MHD patients. At baseline, patients in the high BCL group were older and had a higher prevalence of diabetes mellitus but lower serum albumin, creatinine, and phosphate levels than the patients in the other 2 groups. After adjusting for potential variables, stepwise backward multiple linear regression analysis revealed that age and alanine aminotransferase levels were positively associated with logarithmic transformation of BCLs (log BCLs), while serum albumin levels were negatively associated with log BCLs in CPD patients. The log BCLs were a significant determinant (beta coefficient ± standard error = -0.185 ± 0.074; P = 0.013) of nutritional status and significantly associated with the presence of malnutrition (odds ratio = 2.64; 95% confidence interval: 1.07–6.48; P = 0.035) in CPD patients after adjustment for related variables.

Conclusions

BCL is significantly associated with nutritional status and malnutrition in CPD patients. Therefore, it is important for CPD patients to avoid environmental exposure to cadmium such as through smoking and consumption of cadmium-rich foods.

Cadmium and hypertension in exposed workers: A meta-analysis

OBJECTIVES

In the general population, cadmium seems to be responsible for hypertension, atherosclerosis and an increase in acute coronary events. Therefore, the purpose of this meta-analysis was to analyze controlled studies conducted on cadmium and arterial pressure in occupationally-exposed workers.

MATERIALS AND METHODS

After analyzing all the relevant articles found in the literature, 6 publications were selected.

RESULTS

A higher prevalence of hypertension and higher values of systolic and diastolic blood pressure were recorded in the exposed subjects.

CONCLUSIONS

Cadmium in occupationally-exposed individuals appears to induce an increase in systolic and diastolic blood pressure and an increase in the prevalence of hypertension.

Blood and urine cadmium, blood pressure, and hypertension: a systematic review and meta-analysis

BACKGROUND

Cadmium exposure has been inconsistently related to blood pressure.

OBJECTIVES

We updated and reevaluated the evidence regarding the relationships of blood cadmium (BCd) and urine cadmium (UCd) with blood pressure (BP) and hypertension (HTN) in nonoccupationally exposed populations.

DATA SOURCES AND EXTRACTION

We searched PubMed and Web of Science for articles on BCd or UCd and BP or HTN in nonoccupationally exposed populations and extracted information from studies that provided sufficient data on population, smoking status, exposure, outcomes, and design.

DATA SYNTHESIS

Twelve articles met inclusion criteria: eight provided data adequate for comparison, and five reported enough data for meta-analysis. Individual studies reported significant positive associations between BCd and systolic BP (SBP) among nonsmoking women [ß = 3.14 mmHg per 1 μg/L untransformed BCd; 95% confidence interval (CI), 0.14-6.14] and among premenopausal women (ß = 4.83 mmHg per 1 nmol/L log-transformed BCd; 95% CI, 0.17-9.49), and between BCd and diastolic BP (DBP) among women (ß = 1.78 mmHg comparing BCd in the 90th and 10th percentiles; 95% CI, 0.64-2.92) and among premenopausal women (ß = 3.84 mmHg per 1 nmol/L log-transformed BCd; 95% CI, 0.86-6.82). Three meta-analyses, each of three studies, showed positive associations between BCd and SBP (p = 0.006) and DBP (p < 0.001) among women, with minimal heterogeneity (I² = 3%), and a significant inverse association between UCd and HTN among men and women, with substantial heterogeneity (I² = 80%).

CONCLUSION

Our results suggest a positive association between BCd and BP among women; the results, however, are inconclusive because of the limited number of representative population-based studies of never-smokers. Associations between UCd and HTN suggest inverse relationships, but inconsistent outcome definitions limit interpretation. We believe a longitudinal study is merited.

Blood cadmium level's association with 18-month mortality in diabetic patients with maintenance haemodialysis

BACKGROUND

Cadmium exposure is related to severity of diabetes and diabetes-related organ damage in diabetic patients. Elevated blood cadmium levels (BCLs) are well known in maintenance haemodialysis (MHD) patients but the clinical significance in diabetic MHD patients remains unknown.

METHODS

A total of 212 diabetic MHD patients were enrolled in this 18-month prospective study and were categorized into three equal groups according to the basal BCL: high (> 0.889 μg/L; n = 71), middle (0.373-0.889 μg/L; n = 70) and low (< 0.373 μg/L; n = 71) BCL groups. The mortality and cause of death were recorded and analysed longitudinally.

RESULTS

Patients with high BCL had trends of higher white blood cell counts, glycosylated haemoglobin, phosphate and blood lead levels than other group patients. At the end of the follow-up, 31 patients had died. Kaplan-Meier analysis showed that the high BCL group patients had a higher mortality than other group patients (log-rank test, P = 0.036). Cox multivariate analysis demonstrated that logarithmic BCL was associated with increased hazard ratios (HR) for the all-cause mortality (HR = 2.336, 95% confidence intervals [CI] = 1.099-4.964, P = 0.027) in diabetic MHD patients. Similarly, if the low BCL group was the reference, the high BCL was associated with increased HR for all-cause mortality (HR = 2.865, 95% CI = 1.117-7.353, P = 0.043) in these patients.

CONCLUSIONS

The study results first demonstrated that BCL is associated with increased HR for 18-month all-cause mortality in diabetic MHD patients. Avoiding smoking and high cadmium-containing food may be important in these patients.

Association of environmental cadmium exposure with inflammation and malnutrition in maintenance haemodialysis patients

BACKGROUND

Chronic inflammation and malnutrition are associated with increased risk of cardiovascular death, and may cause protein-energy wasting in individuals with chronic kidney disease. Raised blood cadmium (Cd) levels were observed in maintenance haemodialysis (HD) patients in previous studies. However, the correlation of Cd exposure with inflammation and malnutrition remains uncertain. This study examined the possible adverse effects of environmental Cd exposure in maintenance HD patients.

METHODS

A total of 954 maintenance HD patients were enrolled and divided into four equal-sized groups based on blood Cd levels. Geographic, haematological, biochemical and dialysis-related data were obtained. The analysis included values for nutritional and inflammatory markers.

RESULTS

Abnormal blood Cd levels (> or =1 microg/L) were exhibited in 26.8% (256/954) of studied subjects. More subjects in the highest quartile group were malnourished (chi- square = 23.27; P < 0.0001) and had inflammatory changes (chi-square = 13.99; P = 0.0029) than in the lowest quartile group. Stepwise multiple regression analysis revealed a significant inverse correlation between serum albumin and blood Cd levels. Notably, a 10-fold increase in blood Cd levels was associated with a 0.06 g/dL decrease in serum albumin levels (P = 0.0060). Multivariate regression analysis also demonstrated a positive correlation between inflammatory risk (high-sensitivity C-reactive protein >3 mg/L) and blood Cd levels. The risk ratio of inflammation with a 10-fold increase in blood Cd levels was 1.388 (95% CI: 1.025-1.825, P = 0.0336).

CONCLUSIONS

Environmental Cd exposure is significantly associated with malnutrition, inflammation and even protein-energy wasting in maintenance HD patients. It is important for this population to avoid diets with high Cd concentrations and smoking.

Cadmium excretion predicting hospital mortality and illness severity of critically ill medical patients

OBJECTIVE

To determine the prognostic value of day 1 urine excretion of cadmium (1st DUE-Cd) for predicting outcomes in intensive care unit (ICU) patients.

DESIGN

Prospective study.

SETTING

ICUs in Chang Gung Memorial Hospital, Lin-Kou Medical Center, Taiwan, ROC.

PATIENTS

Two hundred one ICU patients.

INTERVENTIONS

Urine and blood samples were taken within 24 hours after admission.

MEASUREMENTS AND MAIN RESULTS

Disease severity, hospital mortality, and number of organ failures were evaluated in each medical ICU patient. Stepwise multiple linear regression analysis indicated that a history of chronic hepatitis, serum albumin, and glutamic-pyruvic transaminase were significantly related to 1st DUE-Cd after adjusting for other related variables. Cox multivariate analysis revealed that serum blood urea nitrogen level and ICU 1st DUE-Cd were significantly related to hospital mortality after other risk factors and scoring systems were adjusted. Each 1-microg increase in ICU 1st DUE-Cd was associated with a 7% increase in hospital mortality rate. All patients with poisoning magnitude of cadmium excretion (>10 microg/day) died, except one and those with normal cadmium excretion survived. Chi-square values of the Hosmer-Lemeshow goodness-of-fit test were 6.936 (p = 0.544), and area under the receiver operating characteristic curve was 0.868 (95% confidence intervals: 0.82-0.92) for ICU 1st DUE-Cd.

CONCLUSIONS

The ICU 1st DUE-Cd may predict hospital mortality in critically ill medical patients. Because of excess mortality and relatively small sample size, the predictive role of DUE-Cd needs further external validation.

A global perspective on cadmium pollution and toxicity in non-occupationally exposed population

Cadmium is a non-essential element that has high rates of soil to plant transference compared with other non-essential elements, and certain plant species accumulate large amounts of cadmium from low cadmium content soils. In this paper, levels of cadmium found in major food groups are highlighted together with cadmium levels found in liver and kidney samples from non-occupationally exposed populations. Data on human kidney cadmium levels identified recently, including the study in our own laboratory, are compared with older studies. Human-tissue cadmium contents showed large variations among individuals, but sources of the variation remain unknown. Exposure levels of 30-50 microg per day have been estimated for adults and these levels have been linked to increased risk of bone fracture, cancer, kidney dysfunction and hypertension. Increased mortality was found among individuals showing signs of cadmium renal toxicity compared with those without such signs, suggesting that renal toxicity may be an early warning of complications, sub-clinical or clinical morbidity.

Cadmium exposure in tobacco workers: possible renal effects

Cadmium is a nephrotoxic metal widely used in industry and the main source of Cd in general population is smoking. Considering that the source of Cd in cigarettes is the tobacco leaf, the exposure to Cd was evaluated in workers employed at a tobacco leaf processing factory. Blood and urinary Cd levels were measured by flameless atomic absorption spectrometry in 87 workers and 35 controls. Urinary enzymes, total protein, albumin and uric acid were also determined to investigate the possible nephrotoxic effects of Cd. Blood Cd levels were significantly higher in workers (1.63 +/- 1.95 microg/L) than in controls (0.91 +/- 1.15 microg/L) (p = 0.044). The increase observed in urinary Cd levels of workers was non significant (0.56 +/- 0.5 microg/g creatinine in workers and 0.46 +/- 0.5 microg/g creatinine in controls). Both in workers and in controls, subjects smoking >10 cigarettes/day showed significantly increased blood Cd levels compared to non-smokers (p = 0.000 and p = 0.011, respectively). In workers, urinary alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total protein, and uric acid were observed to be significantly increased (p = 0.013, p = 0.000, p = 0.000, p = 0.025, respectively), ALP, GGT and total protein being positively correlated with Cd in urine. In conclusion, the workers in the tobacco leaf processing factory were found to be exposed to Cd compared to the general population. The increase in the urinary enzymes and proteins suggests that an exposure to Cd affects kidney functions even below the toxic limits generally accepted.

Cadmium levels in the lung, liver, kidney cortex, and urine samples from Australians without occupational exposure to metals

The authors undertook this study to assess levels of cadmium exposure in the general population. Samples of lung, liver, and kidney were obtained from 61 cadavers (43 males, 18 females; 2-89 yr of age, mean age = 38.5 yr) who died from accidental causes and who were subject to postmortem examinations at the John Tonge Centre for Forensic Sciences, Queensland Health Scientific Services, Brisbane, Australia, in 1997 and 1998. Samples of bladder urine were also obtained from 22 cadavers. Tissue and urine samples were analyzed for cadmium, zinc, and copper with inductively coupled plasm (ICP) mass spectrometry. The overall mean values for cadmium in the lung, liver, and kidney cortex samples were 0.13, 0.95, and 15.45 microg/gm wet tissue weight. The average renal cadmium level in subjects with high lung-cadmium levels (n = 13) was 6 microg/gm wet tissue weight higher than that of similarly aged subjects who had medium lung-cadmium levels (n = 30). In females, the average level of cadmium in the liver was 74% greater than in males, and the average liver cadmium in females with high lung-cadmium levels was 100% higher than in males in the same age range who had the same high lung-cadmium levels. Renal cadmium accumulation tended to be greater in females than in males who were in the same age range and who had similar lung-cadmium levels, a result that suggested that there was a higher absorption rate of cadmium in females. The mean value for a urinary cadmium excretion of 2.30 microg/gm creatinine was found in a subset of samples that had a mean age of 39 yr and a renal cortex cadmium concentration of 18.6 microg/gm wet tissue weight. Urinary cadmium excretion rates were correlated more strongly with lung and kidney cadmium content than with age or liver cadmium levels. The results suggest that urinary cadmium excretion may be increased in smokers and could provide some estimate of body cadmium burdens in future Australian epidemiological studies.

Blood pressure in relation to dietary calcium intake, alcohol consumption, blood lead, and blood cadmium in female nonsmokers

The interrelationship of dietary calcium (Ca) intake, alcohol consumption, blood lead (BPb), blood cadmium (BCd), age, and body mass index (BMI) to blood pressure was examined in 267 peasant women 40-85 years of age. They were residents of two rural areas in Croatia and differed with regard to dietary Ca intake: 100 women with low Ca intake (approximately 450 mg/day) and 167 women with relatively high Ca intake (approximately 940 mg/day). All of the women were nonsmokers and consumed very little or no alcohol. Median and range BPb values were 74 (29-251) microg/L in women with low Ca intake and 59 (21-263) microg/L in women with high Ca intake (p < 0.0002), whereas corresponding BCd values were 0.6 (0.2-3.6) microg/L and 0.6 (0.3-4.5) microg/L (p > 0.10). Results of multiple regression showed a significant (p < 0.05) increase in systolic blood pressure with age, BMI, and BCd, and marginally with alcohol consumption (multiple r = 0.48, p < 10(- 6)). An increase in diastolic blood pressure was significantly (p < 0.05) associated with BMI, age, and residence area (i.e., it was higher in women with low Ca intake), and marginally with BCd, and alcohol consumption (multiple r = 0.38, p < 10(-6)) When the two groups of women with different Ca intake were subdivided into consumers and nonconsumers of alcohol, BPb was related positively to alcohol consumption and inversely to Ca intake. The highest BPb was found in the subgroup of alcohol consumers with low Ca intake, and the lowest BPb in the subgroup of nonconsumers with high Ca intake: 78 (42-251) microg/L and 51 (22-192) microg/L, respectively (p < 10(-8)). Diastolic blood pressure was significantly higher in the former subgroup as compared to the latter: 95 (72-130) mm Hg and 90 (60-120) mm Hg, respectively (p < 0.05). This cannot be explained by age, BMI, or BCd, which were comparable in the two subgroups. The results indicate that alcohol consumption and low Ca intake can increase BPb, which may significantly contribute to an increase in diastolic blood pressure in female nonsmokers even at relatively low-level Pb exposure.

Evidence for a synergistic interaction between cadmium and endotoxin toxicity and for nitric oxide and cadmium displacement of metals in the kidney

This study was undertaken to examine changes in Zn and Cu homeostasis in the liver and kidney of rats caused by cadmium (Cd) or lipopolysaccharide (LPS) administration. Twenty-five male, 7- to 8-week-old Wistar rats were divided into five groups: saline only treatment, saline treatment and food deprivation, exposure to a single dose of Cd, exposure to LPS alone, and exposure to Cd + LPS. Changes in plasma nitrate concentrations and hepatic and renal Zn and Cu contents were measured together with urinary excretion rates for the metals and nitrate on 3 consecutive days: 24 h before treatment and 24 and 48 h after treatments. Cd exposure alone for 48 h caused a nearly 2-fold increase in plasma nitrate levels with no changes in urinary nitrate excretion whereas LPS treatment caused plasma nitrate levels to increase by 10-fold and urinary nitrate excretion to increase by 4-fold. Administration of LPS 24 h after Cd exposure caused a 10-fold increase in plasma nitrate concentrations and a 100-fold increase in urinary nitrate excretion compared to the rates prior to LPS administration. These results indicate a synergistic interaction between Cd and LPS toxicity. Cd exposure also caused a marked increase in hepatic Zn levels, but LPS did not cause any changes in hepatic Zn or Cu content. In sharp contrast, both Zn and Cu contents were decreased in the kidneys by 16 and 36% in animals exposed to Cd or LPS. A correlation analysis of measured variables reveals that renal Cu contents were inversely associated with plasma nitrate concentrations while urinary Cu excretion on day 3 showed a strong positive correlation with both urinary nitrate and Cd excretions on the same day. A linear regression analysis shows 20% of the variation in urinary Cu excretion was associated with urinary Cd excretion on the same day. It is concluded that reductions in renal Cu contents caused by Cd or LPS administration may be a result of Cd and NO displacement of Cu previously bound to metallothionein.