Occupational Exposure To Cadmium Research Articles

Effect of occupational cadmium exposure on the thyroid gland and associated inflammatory markers among workers of the electroplating industry.

Cadmium (Cd) is widespread throughout the environment and is used in the electroplating industry. It has been found to have an effect on the endocrine system. However, its effects and their underlying mechanisms are still not clear. The aim of this study was to evaluate how cadmium exposure at work affected the levels of thyroid hormones and the associated inflammatory and oxidative markers. This study was conducted in an electroplating industry in Cairo, Egypt. Ninety male cadmium-exposed workers were matched with 90 male unexposed participants. A detailed questionnaire was designed and given to every participant in the study, and full clinical examinations were carried out. Blood samples were collected from all participants for determination of levels of serum cadmium, thyroid hormones, anti-thyroid peroxidase antibody (anti-TPO), interleukin-6 (IL-6), malondialdehyde (MDA), and tumor necrosis factor-alpha (TNF-α). Morning midstream urine samples were obtained to measure urine cadmium levels. Results showed that the total blood and urinary cadmium levels were significantly higher in the exposed group (2.38 ± 0.94μg/L and 5.45 ± 1.92μg/g creatinine, respectively) than in the unexposed group. The serum levels of anti-TPO antibody, TSH, MDA, IL-6, and TNF-α also were significantly higher in the cadmium-exposed group than in the unexposed group. Significant direct relationships were seen between the biological indices of cadmium exposure and anti-TPO antibodies, TSH, IL-6, TNF-α, and MDA. It was concluded that there is a link between occupational cadmium exposure and autoimmune hypothyroidism, inflammatory, and oxidative stress markers.

Cadmium induces epithelial–mesenchymal transition and migration of renal cancer cells by increasing PGE2 through a cAMP/PKA-COX2 dependent mechanism

Environmental or occupational exposure of Cadmium (Cd) is concerned to be a threat to human health. The kidney is main target of Cd accumulation, which increases the risk of renal cell carcinoma (RCC). In addition, low content of Cd had been determined in kidney cancer, however, the roles of presence of Cd in renal tumors progression are still unclear. The present study is proposed to determine the effect of low-dose Cd exposure on the renal cancer cells and aimed to clarify the underlying mechanisms. The cell viability, cytotoxicity, and the migratory effect of low-dose Cd on the renal cancer cells were detected. Moreover, the roles of reactive oxygen species (ROS), Ca2+, and cyclic AMP (cAMP)/protein kinase A (PKA)-cyclooxygenase2 (COX2) signaling, as well as COX2 catalytic product prostaglandin E2 (PGE2) on cell migration and invasion were identified. Our results suggested that low dose Cd exposure promoted migration of renal cancer Caki-1 cells, which was not dependent on Cd-induced ROS and intracellular Ca2+ levels. Cd exposure induced cAMP/PKA-COX2, which mediated cell migration and invasion, and decreased expressions of epithelial-mesenchymal transition (EMT) marker, E-cadherin, but increased expressions of N-cadherin and Vimentin. Moreover, Cd-induced secretion of PGE2 feedback on activation of cAMP/PKA-COX2 signaling, also promoted EMT, migration and invasion of renal cancer Caki-1 cells. This study might contribute to understanding of the mechanism of Cd-induce progression of renal cancer and future studies on the prevention and therapy of renal cell carcinomas.

Occupational exposure of lead and cadmium on adolescent and adult workers of battery recycling and welding workshops: Adverse impact on health

The occupational exposure of toxic metals is an important concern, because of its potential accumulation in living organisms, leading to long term toxic effects. The occupational and environmental contacts of toxic metals, cadmium (Cd) and lead (Pb) have been evaluated by determination of them in biological samples (blood and scalp hair) of adolescent and adults, workers of battery recycling and welding workshops. The age matched adolescent and adult residing in nonindustrial areas were also selected, termed as referent/control subjects. The blood and scalp hair samples of workers and controls were analyzed for Cd and Pb using graphite furnace atomic absorption spectrometry previously decomposed the matrices using acid mixture. The biochemical parameters of workers of both age groups were also evaluated. The average concentrations of Cd and Pb in blood and scalp hair samples of adolescent workers were three fold higher as compared with control subjects. The drinking water in containers of both workshops contained Pb and Cd in two to four and five to thirteen folds, respectively, higher than recommended permissible limits of WHO. The significant correlations between the blood lead levels and hemoglobin (%) in adolescent (r = −0.78). The positive correlation was observed among incidence of blood pressure with Pb and Cd concentrations in biological samples of workers (adults) (r = 0.65 to 0.83). These findings suggest that occupational exposure of toxic metals might be created adverse impacts on workers due to ill management of workshops.

Effects of coenzyme Q10 supplementation on oxidative stress and antioxidant enzyme activity in glazers with occupational cadmium exposure: A randomized, double-blind, placebo-controlled crossover clinical trial.

Iranian Registry of Clinical Trials Registration Number: IRCT2016061228407N1 ( www.who.int/ictrp/network/irct/en/ ).

Impact of occupational cadmium exposure on bone in sewage workers.

Cadmium (Cd) is one of the environmental risk factors for bone loss. The present study included 40 sewage workers occupationally exposed to Cd. Forty nonexposed men were included as a control group. Current smokers represented 65% and 47.5% of the exposed and control groups, respectively. The study aimed to investigate the hazard of occupational Cd exposure on bone health. This was achieved through measuring serum and urinary Cd, and calcium (Ca), in addition to serum osteoprotegerin (OPG) and estrogen receptor-α gene. Results showed significant elevation in serum Cd, OPG, and urinary Ca levels in the exposed compared to the controls. Bony aches and joint pain were more prevalent among the exposed workers. Serum and urinary Cd increased in exposed smokers relative to control smokers. Also, serum OPG levels showed significant rise among exposed smoker and nonsmoker compared to control smoker and nonsmoker groups. Serum Cd level increased significantly in PP and pp genotypes in exposed workers compared to controls, while elevated levels of serum OPG was observed in PP and Pp genotypes in exposed workers relative to controls. Urinary Cd exhibited significant rise in both PP and pp genotypes in exposed workers, while Ca excretion was elevated in pp genotype only. The study reflected an association of genetic predisposition and Cd exposure in progression of osteoporosis. Further research is needed to explain the mechanisms of Cd impact on bone. The role of smoking is important and hence smoking cessation programs are essential for sewage workers.

Effects of occupational cadmium exposure on workers' cardiovascular system

Objective: To investigate the effects of cadmium exposure on cardiovascular system of occupational workers. Methods: Cross-sectional study was applied to 992 workers in a nickel-cadmium battery plant in November, 2011, of which 749 were cadmium exposed workers and 243 were controls without cadmium and other expose. Urinary cadmium、electrocardiogram (ECG) and blood pressure were examined simultaneously among 992 workers. The risk factors of ECG abnormality rate and hypertension rate were analyzed by Logistic regression. Results: The level of urinary cadmium in cadmium exposed workers was significantly higher than controls (8.89±4.00 vs 1.34±1.18 μg/g creatinine, P<0.01) . Urinary cadmium level in women was significantly higher than men in both exposure and control group (P<0.05) . According to the group of working years, Urinary cadmium level raised with the increase of working years (F=28.272, P<0.001) . The ECG abnormality rate and hypertension rate of cadmium exposed workers were higher than that of control group, the differences were all statistically significant (P<0.01) . The abnormal rate of ECG and the hypertension rate increased with the prolonging of working years and demonstrated dose-response relationship. With the increase of urinary cadmium level, the abnormal rate of ECG and hypertension rate raised (OR=1.11, P<0.01) and (OR=1.15, P<0.01) respectively. Conclusion: Occupational cadmium exposure increased the abnormal rate of ECG and blood pressure and therefore damaged cardiovascular system of workers. This study provided base data for protecting health of cadmium exposed workers.

Maternal occupational cadmium exposure and nonsyndromic orofacial clefts.

Cigarette smoking is a well-studied risk factor for orofacial clefts (OFCs). Little is known about which constituents in cigarette smoke contribute to this teratogenicity in humans. One constituent, cadmium, has been associated with OFCs in animal studies; in humans, the role of maternal cadmium exposure on OFCs, independent of cigarette smoke, is unclear. In particular, the relation between maternal occupational cadmium exposure and OFCs is largely unexplored. Using data from a large, population-based case-control study, we compared expert rater assessed maternal occupational cadmium exposure from self-reported occupational histories during the period 1 month before through 3 months after conception between OFC cases (n = 1,185) and unaffected controls (n = 2,832). Multivariable logistic regression analyses were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals for any (yes/no) and cumulative (no, low, high exposure) occupational cadmium exposures and all OFCs, cleft lip ± cleft palate (CL/P) and cleft palate (CP). Overall, 45 mothers (cases = 13, controls = 32) were rated as having occupational cadmium exposure. Comparing all OFCs to controls, we observed inverse, nonsignificant aORs for any or low exposure, and positive, nonsignificant aORs for high exposure. Where data were available, aORs for CL/P and CP tended to parallel those for all OFCs. To our knowledge, this is the first study to specifically examine maternal occupational cadmium exposure and OFCs, using expert rater exposure assessment. The small numbers of exposed mothers observed, however, led to imprecise estimates. Continued research using more detailed occupational exposure assessment and increased sample sizes is recommended.

Abstract 5251: Chemoprevention of cadmium induced prostate carcinogenesis

Abstract Cadmium is known carcinogen that causes damages to multiple organs. Cadmium acts as an agonist and activates androgen receptor (AR) in prostate epithelial cells which in turn promotes the carcinogenesis of prostate. Studies have indicated that occupational exposure of cadmium is a risk factor for prostate cancer and hence there is an immediate need to prevent cadmium induced prostate cancer in occupational workers. Various reports have shown that inhibition of AR signaling by AR inhibitors suppressed cadmium induced prostate carcinogenesis. So, the present study focuses to identify dietary agent which can effectively prevent cadmium induced prostate cancer and to dissect the mechanism of action on malignant transformed cells. We have disclosed one such compound, 6-(3, 9-dihydroxy-2-prenylcoumestan (Psoralidin) (Pso) a non-toxic, orally bioavailable compound, which effectively targets only prostate cancer cells and innocuous to healthy cells. Our results have shown cadmium transformed prostate epithelial cells (CTPE) exhibits high proliferative and high colony forming ability in soft agar assays. However, treatment of CTPE cells with Pso resulted in growth inhibition, without causing toxicity to normal prostate epithelial cells (RWPE-1). Finally, in vivo experiments showed that oral administration of Pso (20 mg/kg/BW) effectively suppresses the growth in CTPE xenografts, at physiologically achievable doses without any toxicity. The pathological findings suggest that CTPE tumors exhibits epithelial and mesenchymal transition (EMT) phenotype and infiltrating margins into the surrounding muscle and adipose tissue. However, Psoralidin treated tumors showed a decrease in tumor size with a significant central necrosis (up to 60% of the tumor size). More specifically, margins of Psoralidin treated tumors are less infiltrative and becoming more well circumscribed. We have also noticed that the mesenchymal component is not present and the only viable tumor is the epithelial one after Pso treatment. Altogether, our results confirm that consumption of natural compounds such as Psoralidin may play an important role in the chemoprevention for cadmium induced prostate carcinogenesis. Citation Format: Suman Suman, Trinath P. Das, Houda Alatassi, Murali K. Ankem, Chendil Damodaran. Chemoprevention of cadmium induced prostate carcinogenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5251.

Cadmium burden and renal dysfunction among residents in cadmium-polluted areas: A 3-year follow-up study

To investigate dynamic change of cadmium body burden and renal dysfunction among residents living in cadmium-polluted areas. From April to July of 2011, the cadmium-polluted areas of northern Guangdong province in China was chosen as the study site. Based on the levels of cadmium pollution in soil and rice, the survey areas were divided into low exposed group (average concentration of cadmium was 0.15-0.40 mg/kg, 0.5-1.0 mg/kg in rice and soil, respectively) and high exposed group (average concentration of cadmium was >0.40 mg/kg, >1.0 mg/kg in rice and soil, respectively). Stratified random sampling and cluster sampling method of epidemiological investigations were carried out among 414 local residents who lived in cadmium exposure areas for more than 15 years, aged above 40, and without occupational cadmium exposure, including 168 and 246 residents in low and high exposed group, respectively. From March to June of 2014, 305 respondents of those who participated in 2011 were successfully traced, including 116 and 189 respondents in low and high exposed group, respectively. We used health questionnaires to acquire their health status. Home-harvested rice and vegetable samples were collected using quartering method for detection of cadmium level, including 190 rice samples, 161 vegetable samples in 2011 and 190 rice samples, 153 vegetable samples in 2014. Urine specimens of residents were collected for the detection of urinary cadmium and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase (NAG) and β2-microglobulin (β2-MG), respectively. In 2011 and 2014, Chi-square test was used to investigate the differences of abnormality of cadmium concentration in rice, vegetables and urinary cadmium, β2-MG, and NAG that were expressed as odds ratio(OR) and 95% confidence intervals (95%CI). In 2011 and 2014, cadmium concentration P50 (P25-P75) in rice was 0.43 (0.17-1.10) mg/kg, and 0.42 (0.20-1.14) mg/kg, respectively (Z=-0.77,P=0.440). In 2011 and 2014, cadmium concentrations P50 (P25-P75) in vegetables were 0.13 (0.07-0.34) mg/kg, and 0.25(0.12-0.59) mg/kg, respectively, with abnormal rates of 38.5%(62/161) and 60.8%(93/153), respectively. In 2014, both average concentration and abnormal rate of cadmium in vegetables were higher than those in 2011 (Z=-4.69, P<0.001 and χ(2)=15.58,P<0.001). Concentrations of urinary cadmium P50 (P25-P75) in high exposed group were 7.90 (3.96-14.91) μg/g creatinine, 8.64 (4.56-17.60) μg/g creatinine in 2011 and 2014, respectively. Contrary to that in 2011, urinary cadmium of high exposed group was significantly increased in 2014 (Z=-2.80, P=0.005). In 2011 and 2014, concentrations of β2-MG, NAG P50 (P25-P75) were 0.15(0.07-0.29) μg/g creatinine, 0.15 (0.07-0.45) μg/g creatinine, and 7.12 (5.05-10.65) U/g creatinine, 13.55(9.1-19.84) U/g creatinine, respectively, with abnormal rates of 7.5% (23/305), 15.1% (46/305), 8.2% (25/305) , and 33.8% (103/305), respectively. Compared with baseline in 2011, average concentrations of β2-MG, NAG significantly increased in 2014 (Z=-2.263, P=0.024 and Z=-12.52, P<0.001), and abnormal rates of β2-MG, NAG were also higher in 2014 (χ(2)=15.61 , P<0.001 and χ(2)=64.72, P<0.001), with odds ratio(OR) of 2.00 (95%CI:1.23-3.24) and 4.12 (95%CI:2.87-5.92). Environmental cadmium pollution of crops such as rice and vegetables in survey areas continued to remain high. Body burden of cadmium might kept at sustainably high levels and renal dysfunction was worsened after continuous, long-term cadmium exposure. Our results suggested that NAG might be more sensitive than β2-MG to serve as an indicator for an individual's future tubular function.

Effect of Occupational Cadmium Exposure on Parathyroid Gland.

BACKGROUND:Cadmium (Cd) is used in many industries. High-level exposure is associated with severe kidney and bone damage.AIM:This study investigates the possible effect of occupational cadmium exposure on parathyroid gland and some minerals in workers.METHODS:Environmental air monitoring of cadmium was done. Serum and urine cadmium levels, kidney function, some minerals, and plasma parathormone were estimated in the studied groups.RESULTS:The exposed workers had significantly higher Cd concentration in serum and urine than controls. The mean levels of plasma parathyroid hormone, serum phosphorus and magnesium were significantly lower among the exposed group. However, the mean levels of serum creatinine and calcium were significantly higher in the same group when compared to referents. There was a significant positive correlation between Cd concentration in the serum and urine for the exposed group. The biological Cd exposure indices correlated positively with serum calcium and negatively with plasma PTH level. The prevalence of musculoskeletal complaints, bone ache, joint pain and muscle spasm were more prevalent among the exposed workers compared with the controls with odds ratio 4.316, 3.053 and 3.103 respectively.CONCLUSIONS:Occupational cadmium exposure has an adverse effect on PTH level and serum human minerals.

Cadmium Exposure is Associated with the Prevalence of Dyslipidemia

Background: Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the prevalence of dyslipidemia, we examined the associations between blood cadmium concentration and the prevalence of dyslipidemia in workers occupationally exposed to cadmium in China. Methods: A cross-sectional survey on demographic data, blood cadmium level and lipid profile in cadmium exposed workers from seven cadmium smelting factories in central and southwestern China was conducted. We measured blood cadmium concentration and lipid components of 1489 cadmium exposed workers. The prevalence of dyslipidemia was compared across blood cadmium quartiles. Associations between the blood cadmium concentrations and the prevalence of dyslipidemia were assessed using confounder adjusted linear and logistic regressions. Results: The blood cadmium concentration was 3.61±0.84µg/L ( mean ±SD). The prevalence of dyslipidemia in this occupational population was 66.3%. Mean blood cadmium concentration of workers with dyslipedemia was significantly higher than that of workers without dyslipidemia (p <0.01). The prevalence of dyslipidemia increased dose-dependently with elevations in blood cadmium concentrations (p for trend <0.001). Elevated levels of blood cadmium were associated with BMI, education attainment, income, smoking status and duration of exposure (all p <0.01). Furthermore, the profile of blood lipid was obviously changed in this occupational population. The prevalence of high TC, high TG, Low HDL-C and high LDL-C rose with increases in blood cadmium levels dose-dependently (p for trend <0.001). The odds ratios (95% confidence interval) for dyslipidemia across the increasing blood cadmium quartiles were 1.21(1.16-1.55), 1.56(1.11-1.87), 1.79(1.26-2.25) respectively (referencing to 1.00; p for trend <0.001), after multivariate adjustment for BMI, education attainment, income, lifestyle factors and duration of exposure, the association between blood cadmium concentrations and the prevalence of dyslipidemia remained unchanged (all p for trend <0.001). Conclusion: Elevated blood cadmium concentration is associated with prevalence of dyslipidemia. Cadmium exposure could alter lipid metabolism in humans. It is imperative to control cadmium exposure of occupational population in cadmium related industries and reduce adverse health effects.

Impact of occupational cadmium exposure on spirometry, sputum leukocyte count, and lung cell DNA damage among Indian goldsmiths.

Cadmium is frequently used in manual jewelry industries. Although its toxicity on lung function is well-known, the mechanism is not well-understood. Among 26 goldsmiths exposed to cadmium (mean age 35.9 ± 5.0 years) and 17 referent workers without direct exposure (36.6 ± 6.6 years), we measured blood and urinary cadmium concentration and performed spirometry and quantified leukocytes and comet formation in the cells from spontaneously expectorated sputum samples. The goldsmiths had higher cadmium concentration in urine (mean 6.14 ± 1.63 vs. 0.47 ± 0.17 μg/dl) and blood (0.90 ± 0.23 vs. 0.02 ± 0.007 μg/dl) than the referents, which were inversely associated with FEV1 /FVC. Cadmium exposure also resulted in higher neutrophils (%) and lower macrophage (%) prevalence in the sputum and also caused substantial DNA damage in the lung cells among the goldsmiths than the referents (69 vs. 14%). Altered lung function among cadmium-exposed goldsmiths was associated with enhanced inflammatory response and increased cellular DNA damage in the lungs.

Associations between cadmium exposure and neurocognitive test scores in a cross-sectional study of US adults.

BackgroundLow-level environmental cadmium exposure and neurotoxicity has not been well studied in adults. Our goal was to evaluate associations between neurocognitive exam scores and a biomarker of cumulative cadmium exposure among adults in the Third National Health and Nutrition Examination Survey (NHANES III).MethodsNHANES III is a nationally representative cross-sectional survey of the U.S. population conducted between 1988 and 1994. We analyzed data from a subset of participants, age 20–59, who participated in a computer-based neurocognitive evaluation. There were four outcome measures: the Simple Reaction Time Test (SRTT: visual motor speed), the Symbol Digit Substitution Test (SDST: attention/perception), the Serial Digit Learning Test (SDLT) trials-to-criterion, and the SDLT total-error-score (SDLT-tests: learning recall/short-term memory). We fit multivariable-adjusted models to estimate associations between urinary cadmium concentrations and test scores.Results5662 participants underwent neurocognitive screening, and 5572 (98%) of these had a urinary cadmium level available. Prior to multivariable-adjustment, higher urinary cadmium concentration was associated with worse performance in each of the 4 outcomes. After multivariable-adjustment most of these relationships were not significant, and age was the most influential variable in reducing the association magnitudes. However among never-smokers with no known occupational cadmium exposure the relationship between urinary cadmium and SDST score (attention/perception) was significant: a 1 μg/L increase in urinary cadmium corresponded to a 1.93% (95%CI: 0.05, 3.81) decrement in performance.ConclusionsThese results suggest that higher cumulative cadmium exposure in adults may be related to subtly decreased performance in tasks requiring attention and perception, particularly among those adults whose cadmium exposure is primarily though diet (no smoking or work based cadmium exposure). This association was observed among exposure levels that have been considered to be without adverse effects and these levels are common in U.S. adults. Thus further research into the potential neurocognitive effects of cadmium exposure is warranted. Because cumulative cadmium exposure may mediate some of the effects of age and smoking on cognition, adjusting for these variables may result in the underestimation of associations with cumulative cadmium exposure. Prospective studies that include never-smokers and non-occupationally exposed individuals are needed to clarify these issues.

Adverse effects of low occupational cadmium exposure on renal and oxidative stress biomarkers in solderers

ObjectivesRecent studies suggest adverse health effects after low exposure to cadmium (Cd). Brazing with Cd-containing solder exposes workers to Cd. The purpose of this study was to assess: (1) indicators...

Effects of combined occupational cadmium and lead exposure on renal biomarkers

Effects of combined occupational cadmium and lead exposure on renal biomarkers

Toxicological aspects of cadmium and occupational health activities to prevent workplace exposure in Japan: A narrative review

Chemicals are an essential part of modern manufacture processes. Their use must be managed with great attention in occupational settings to avoid serious detrimental effects to the health of employees. For example, cadmium compounds are indispensable for the production of nickel-cadmium rechargeable batteries or as chemical stabilizer in plastics. It is an exceptionally toxic heavy metal and personnel exposed to cadmium in the workplace meet with potential health risks that can lead to the development of kidney, skeletal and respiratory disorders. In consequence, proactive and systematical development of occupational hygiene and health activities are necessary to reduce chemical exposure to cadmium in the workplace. This review describes the known facts of cadmium toxicity, the biological effects of cadmium exposure, possible regulation measures to prevent occupational cadmium exposure in three industrial health management systems and discusses future cooperation programs in these systems, proactive safety activities and occupational safety and health management strategies.

Occupational cadmium exposure and calcium excretion, bone density, and osteoporosis in men

Exposure to cadmium has been associated with osteoporosis and fracture risk in women and the elderly, but studies in middle-aged men are lacking. In 83 male (ex)workers (mean age 45 years; range 24 to 64 years) in a radiator factory using cadmium-containing solder, we investigated the association between urinary cadmium excretion (as an index of lifetime body burden); bone mineral density (BMD) in the distal forearm, hip, and lumbar spine (by dual-energy X-ray absorptiometry); and urinary calcium excretion. Geometric mean urinary cadmium concentration was 1.02 microg/g of creatinine (5th to 95th percentile 0.17 to 5.51 microg/g). BMD was negatively correlated with urinary exposure to cadmium. The partial correlation coefficients (r) adjusted for age, body-mass index, and current smoking were -0.30 (p = .008) for BMD in the forearm, -0.27 (p = .017) in the hip, and -0.17 (p = .15) in the spine. Urinary calcium correlated positively (r = 0.23, p = .044) with the urinary cadmium excretion. Adjusted for the same covariates, the risk of osteoporosis (defined as a T-score below -2.5 in at least one measured bone site) increased dose dependently. Compared with the lowest tertile of urinary cadmium, the risks were 4.8- and 9.9-fold higher in the middle and highest tertiles, respectively. Only four (5%) men had evidence of renal tubular dysfunction (beta(2)-microglobulin > 300 microg/g of creatinine). Even in the absence of renal tubular dysfunction, occupational exposure to cadmium is associated in men with lower BMD values, a higher risk of having osteoporosis, and a higher urinary calcium excretion, suggesting a direct osteotoxic effect of cadmium.

EVALUATION OF HEALTH HAZARDS AMONG CADMIUM-EXPOSED WORKERS

Introduction: Cadmium is a cumulative multisystem metallic toxin widely used in industry causing occupational exposure, while the main source of cadmium in the generalpopulation is diet and smoking.Aim of the work: To demonstrate the hazardous effects of long-term occupational exposure to cadmium as a multisystem metallic toxin. Subjects and methods: The study included 42 male workers exposed to cadmium from the electroplating sections of one factory, with a mean age of (41.19 ± 1.44) years and 30 control subjects with a mean age of (48.33 ± 1.85) years. The two groups were matched as regards age, sex and socioeconomic status. Individuals included in the present study had to respond to a questionnaire and were subjected to thorough clinical examination, assessment of liver and kidney functions, serum electrolytes, blood cadmium level - as an exposure biomarker - complete urine analysis, ventilatory functionsand prostate specific antigen as an early predictor of prostatic cancer. Results: The prevalence of clinical manifestations was significantly higher among the exposed versus the control group. The blood cadmium and the PSA levels were foundto be higher among the exposed group. Ventilatory functions showed statistically significant difference between both groups indicating an obstructive pattern due to inhalation of cadmium fumes. Also, there was a statistically significant difference between both groups regarding levels of blood urea, serum creatinine and some serum electrolytes.Urine analysis showed higher protein excretion in the exposed group. Conclusion: Chronic occupational cadmium exposure in egyptian workers causes damage to different body systems and results in their dysfunction. Prostate specific antigen(PSA) can be used for screening of prostate cancer among cadmium-exposed workers.

Metallothionein I Isoform mRNA Expression in Peripheral Lymphocytes as a Biomarker for Occupational Cadmium Exposure

It is reported that metallothionein (MT) mRNA expression in human peripheral blood lymphocytes (HPBLs) could be used as exposure biomarkers in occupationally cadmium-exposed workers. Several MT isoforms have been identified in humans. The relationship between MT isoforms and cadmium toxicity has not been fully elucidated in occupational settings. In this study, the MT-IA, IE, IF, IX mRNA expressions in HPBLs were tested by RT-PCR technique, and the relationship between MT isoforms mRNA expression and cadmium-induced renal dysfunction was evaluated in cadmium-exposed workers. The MT-IE, IF, IX mRNA levels were found to increase with increasing blood cadmium (BCd) levels and MT-IA mRNA levels increased with increased urinary cadmium (UCd) levels. The MT-IE, IF, IX mRNA levels were significantly correlated with the BCd levels (P < 0.05), and MT-IA mRNA levels were significantly correlated with the UCd levels. This confirmed that MT-I isoforms mRNA expression in HPBLs is a biomarker of cadmium exposure and internal dose. The MT-IA mRNA levels were significantly correlated with renal dysfunction biomarkers, such as urinary beta2-microglobulin (Ubeta2-MG) (r = 0.294, P < 0.01) and urinary albumin (UALB) (r = 0.305, P < 0.01). The latter finding indicates that MT-IA mRNA expression in HPBLs may be used as a biomarker for renal dysfunction in occupational cadmium exposure.

Individual Susceptibility to Cadmium Toxicity and Metallothionein Gene Polymorphisms: with References to Current Status of Occupational Cadmium Exposure

The incidence of serious poisoning caused by occupational cadmium exposure has declined over the past four decades due to improvements in the work environment. However, long-term low-level exposure to cadmium needs to be addressed. For workers in industries that handle cadmium, it is necessary to consider the daily cadmium intake from contaminated foods such as cereals and rice in addition to the occupational exposure, since workers might be exposed to higher levels of cadmium from a combination of these sources. Cadmium accumulates in the renal cortex by the long-term exposure along with increased concentrations of metallothionein, an important protein for protection from cadmium toxicity. However, some individuals have lower metallothionein levels despite increased cadmium accumulation in the kidneys. This article describes the strategy method for analyzing individual susceptibility to cadmium toxicity and genetic polymorphisms of metallothionein, with reference to the current status of occupational cadmium exposure.