Urinary Cadmium Levels Research Articles

Association of environmental cadmium exposure and periodontal disease

Background and Aims: Cadmium adversely affects bone remodeling and is therefore possible that environmental cadmium exposure may be a risk factor for periodontal disease-related bone loss. Aim of the present study was to assess the association between environmental cadmium exposure and periodontal disease. Settings and Design: The study was conducted in the Department of Periodontics, in our institution, Mangalore and sample size consisted of 100 patients (two groups of 50 patients each). Materials and Methods: Gingival Index, periodontal probing depth and clinical attachment loss was estimated to ascertain the gingival and periodontal status of subjects. Urine samples were collected from the subjects and biochemical analysis was done to estimate urine cadmium levels. Statistical Analysis: Results obtained were then statistically analyzed using Mann-Whitney U-test and correlation was done using Karl Pearson's correlation. Results: There was an increased concentration of urinary cadmium in periodontitis patients when compared with the healthy controls and there was a positive correlation between age and cadmium concentrations. Conclusion: Although information on the oral health effects of cadmium remains limited, the results of this study suggests that cadmium exposure may be an important risk factor for periodontal disease in adults.

비산단지역 환경오염 수준 및 주민의 생체지표 모니터링

Objectives: The main purpose of this study is to produce background data which can be compared with data on vulnerable areas such as industrial complexes in Ulsan, SihwaBanwol, Gwangyang, Yeosu, Pohang, Cheongju and Daesan in Korea. Methods: This study was performed on 1,007 local residents in Gangneung using personal questionnaires and medical check-up. Environmental pollutants including heavy metals in blood and urine were analyzed and the results are as follows. Results: According to the results of medical check-up, 705 subjects were "Normal (A and B)", 232 subjects were "Disease doubtful (R1)" and 70 subjects were "High blood pressure or Diabetes doubtful (R2)". Regarding geometric mean concentration, blood lead was 1.57 <TEX>${\mu}g/dL$</TEX>, urine cadmium was 0.82 <TEX>${\mu}g/g-cr$</TEX>, urine mercury was 0.98 <TEX>${\mu}g/g-cr$</TEX> and urine arsenic was 15.78 <TEX>${\mu}g/g-cr$</TEX>. In the analysis of 11 kinds of VOCs in blood, vinyl chloride, 1,3-butadiene and dichloroethylene were not detected, while the detection rate of other chemicals was above 70% except chloroform(49.7%) and trichloroethylene(19.0%). In analysis of 16 kinds of PAHs in blood, 10 kinds showed more than 80% in detection rate. Also, detection rate of 4 kinds of PCBs in blood ranged 52 to 78%. Conclusions: Compared with industrial compelxes, the concentration of blood lead was lower, while urine cadmium and mercury levels were similar. Also, urine arsenic ranged at a significant level. Further study is required to find the cause of regional differences in concentrations of environmental pollutants.

Cadmium exposure is accompanied by increased prevalence and future growth of atherosclerotic plaques in 64‐year‐old women

There is currently widespread exposure to the toxic metal cadmium through the diet as well as through smoking, and it has been suggested that cadmium exposure may increase the risk of cardiovascular disease. Here we examined whether cadmium exposure is associated with prevalence and growth of atherosclerotic plaques in the carotid arteries. The analyses were performed in a screening-based cohort of 64-year-old Caucasian women with stratified, random selection to groups with normal glucose tolerance, impaired glucose tolerance and diabetes (n=599). We measured cadmium concentrations in blood and urine at baseline. In addition, we performed ultrasound examination to determine the prevalence and area of atherosclerotic plaques in the carotid arteries and assessed smoking history and other cardiovascular risk factors at baseline and at a follow-up examination after a mean of 5.4years. At baseline, blood cadmium levels were associated with increased risk of plaque and a large plaque area after adjustment for confounders. In women who had never smoked, blood cadmium levels correlated positively with plaque area at baseline. The occurrence of large plaques and the change in plaque area at follow-up were associated with blood and creatinine-corrected urinary cadmium concentrations at baseline after adjustment for confounders. Blood and urine cadmium levels added information to established cardiovascular risk factors in predicting progress of atherosclerosis. We have shown that cadmium levels in blood and urine are independent factors associated with the development of atherosclerotic plaques at baseline as well as prospectively. This novel observation emphasizes the need to consider cadmium as a pro-atherogenic pollutant.

Relation of child birth and breast-feeding burden with cadmium and tubular dysfunction marker levels in urine of adult women in non-polluted areas in Japan

Cd absorption may be enhanced in association with iron (Fe) deficiency. Women have increased risks of Fe loss at the time of child birth as well as breast-feeding of children. Possible effects of these two factors were investigated in the present study. Data were drawn from previous publications from this group on Cd and tubular dysfunction markers (i.e., α1-microglobulin, β2-microglobulin, and N-acetyl-β-D-glucosaminidase) in urine of adult women in non-polluted areas in Japan. Information including age, smoking, number of children, and types of child feeding was obtained by self-administered questionnaires at the time of urine sampling. In practice, 17,468 cases were available, from which 12,869 cases were employed in the present analyses after exclusion of smokers, former or current patients of anemia or hypertension, and those with incomplete answers. Lactation burden was scored after coding of breast, mixed, and bottle feeding with 2, 1, and 0 for each child followed by summation for all children born to a mother. In order to exclude possible effect of aging, women were stratified by 5years of age to randomly select equal numbers of cases and controls, followed by summation for all ages for comparison. The arithmetic mean age and the geometric mean Cd (as observed) were 49.7years and 1.13μg/l urine. The number of children was 0-7, and lactation burden score ranged from 0-12. Multiple regression analyses were conducted with age and either number of children or lactation burden scores as independent variables and Cd as a dependent variable. The results showed that age was an influential variable. Comparison after matching for age showed that having 1, 2, or 3 children or lactation burden score up to 2 were associated with a significant increase in Cd. Lactation burden score up to 2 was also associated with increased Cd in urine and such trend persisted up to the highest score of 5-12. The results of trend tests were generally in agreement with these observations. Further comparison after age-matching showed that women having 2 or 3 children but no lactation burden had higher Cd than those with no children. In contrast, Cd was not higher for those having 2 or 3 children with substantial lactation scores (i.e., 2-4 or 3-6) than for those with the same number of children without lactation burden. Giving birth to 1-3 children was associated with an increase in urinary Cd, suggesting that child birth might be associated with elevation in Cd body burden. The effect of lactation is probably attributable to that of number of children. Further studies are necessary to examine whether the association is also observable in mothers who have 3 or more children.

The Reference Dose for Subchronic Exposure of Pigs to Cadmium Leading to Early Renal Damage by Benchmark Dose Method

Pigs were exposed to cadmium (Cd) (in the form of CdCl(2)) concentrations ranging from 0 to 32mg Cd/kg feed for 100 days. Urinary cadmium (U-Cd) and blood cadmium (B-Cd) levels were determined as indicators of Cd exposure. Urinary levels of β(2)-microglobulin (β(2)-MG), α(1)-microglobulin (α(1)-MG), N-acetyl-β-D-glucosaminidase (NAG), cadmium-metallothionein (Cd-MT), and retinol binding protein (RBP) were determined as biomarkers of tubular dysfunction. U-Cd concentrations were increased linearly with time and dose, whereas B-Cd reached two peaks at 40 days and 100 days in the group exposed to 32mg Cd/kg. Hyper-metallothionein-urinary (HyperMTuria) and hyper-N-acetyl-β-D-glucosaminidase-urinary (hyperNAGuria) emerged from 80 days onwards in the group exposed to 32mg Cd/kg feed, followed by hyper-β2-microglobulin-urinary (hyperβ2-MGuria) and hyper-retinol-binding-protein-urinary (hyperRBPuria) from 100 days onwards. The relationships between the Cd exposure dose and biomarkers of exposure (as well as the biomarkers of effect) were examined, and significant correlations were found between them (except for α(1)-MG). Dose-response relationships between Cd exposure dose and biomarkers of tubular dysfunction were studied. The critical concentration of Cd exposure dose was calculated by the benchmark dose (BMD) method. The BMD(10)/BMDL(10) was estimated to be 1.34/0.67, 1.21/0.88, 2.75/1.00, and 3.73/3.08mg Cd/kg feed based on urinary RBP, NAG, Cd-MT, and β(2)-MG, respectively. The calculated tolerable weekly intake of Cd for humans was 1.4 μg/kg body weight based on a safety factor of 100. This value is lower than the currently available values set by several different countries. This indicates a need for further studies on the effects of Cd and a re-evaluation of the human health risk assessment for the metal.

거주지와 산업단지간의 거리와 혈 중 납 농도 및 요 중 카드뮴 농도의 상관관계에 관한 연구

Objectives: The goal of this study was to investigate the relationships between proximity to an industrial complex and blood lead levels and urinary cadmium levels. Methods: We conducted a questionnaire survey and analyzed blood lead and urinary cadmium levels using Atomic Absorption Spectrometry (AAs). Data was analyzed using logistic regression analysis. All statistical analyses were conducted with SAS software version 9.2. The distance between the residence and an industrial complex was calculated through a Geographical Information System (GIS). Results: A total of 967 residents living near a large petrochemical complex in Ulsan participated. The geometric mean levels of blood lead and urinary cadmium were (male: , female: ), and creatinine (male: cr. female: cr.), respectively. Blood lead and urinary cadmium levels both increased with age and were higher among smokers compared to never smokers. Both significantly showed a decreasing trend with rising income. Results from multiple logistic regression analysis showed that urinary cadmium levels for subjects aged less than 20 years old were negatively associated with distance from the industrial area to the residence. The results, however, indicated that the blood lead levels were positively associated with the distance. Conclusions: The results of this study support that proximity to an industrial complex is related to urinary cadmium values for children. A positive finding with blood lead can be explained by the ambiguity of lead exposure sources in the general environment.

Association of past diseases with levels of cadmium and tubular dysfunction markers in urine of adult women in non-polluted areas in Japan

Whereas information has been accumulating on the association of anemia and other diseases with cadmium (Cd) burden, histories of past diseases of the examinees are often not taken in account when the results of health examination are evaluated for cadmium exposure-related health effects on general populations. The present study was initiated to examine the possible association of previous diseases with Cd exposure parameters, taking advantage of compiled data on adult women. Data were cited from previous publications of this research group on Cd, α1-microglobulin (α1-MG), β2-microglobulin (β2-MG), N-acetyl-β-D-glucosaminidase (NAG) and urine density makers (i.e., creatinine and specific gravity) in the urine of more than 17,000 adult women in non-polluted areas in Japan. Information on previous disease history together with age and smoking habits was obtained by self-administered questionnaires, and 13,031 never-smoking women were selected for the present analyses. To compare the cases with disease history, control cases were randomly selected after stratification by 5 years of age at a ratio of one case to three controls from those with no disease history; summation for all age strata made up the control groups for the disease group in concern. The random sampling to set up control groups was repeated three times in total. The difference between the disease group and control groups was considered valid in cases the difference was statistically significant (p ≦ 0.05), in all three cases after correction (or non-correction) for urine density, and the same results were obtained when compared with the three different control groups. In the anemia group, Cd-U was higher over corresponding three control groups, although none of α1-MG-U, β2-MG-U or NAG-U showed significant changes. In the diabetes mellitus group, NAG-U was higher than in the controls, but such differences were not observed in Cd-U or β2-MG-U. The elevation in α1-MG-U was not reproducible. In the case of the hypertension group, the elevations in Cd-U, α1-MG-U, and β2-MG-U were observed, but changes in NAG-U could not be confirmed. In the analysis of dose-response relationship, the diabetes mellitus group showed increases in the slope for β2-MG-U and in the intercept for NAG-U. No changes in dose-response relationship were observed in other disease groups as compared with the corresponding control groups. Care should be taken in evaluating Cd-related health examination results for those with history of diseases such as hypertension, anemia and diabetes mellitus in particular.

Long-term Exposure to Cadmium in Food and Cigarette Smoke, Liver Effects and Hepatocellular Carcinoma

Rising incidence of hepatocellular carcinoma (HCC) has been noted in recent years along with diabetes for which reasons and mechanisms are unclear. The rise in HCC is attributed to increasing rates of hepatitis C virus (HCV) infections while increases in diabetes are attributed to obesity. Increased HCC risk has also been noted in diabetes and obesity. Cadmium, a common food contaminant and a constituent of cigarette smoke, is one of ten chemicals considered by the World Health Organization to be of major public health concern. A correlation of cadmium intakes and increased HCC mortality risk has been noted in an ecological study while both hepatocellular carcinoma and hepatic adenoma occurred in cadmium-exposed mice. In the U.S. NHANES III, urinary cadmium levels, indicative of long-term exposure, have been associated with pre-diabetes and diabetes in a dose dependent manner. Intriguing possibility is that cadmium may increase HCC risk through increasing the frequency of hepatogenous diabetes. Overall aim of the present review is to explore if cadmium is a relevant risk factor in chronic liver disease and a rising HCC incidence. It will highlight cadmium levels detectable in various foods, livers, kidneys and urine samples of humans together with global health threat of ingested cadmium, pointing to measures for reducing exposure and a need for revision of guidelines for safe intake levels. Lastly, it will examine evidence for potential roles of cadmium in chronic liver diseases and HCC risk in a call for human case-control studies and animal experiments to elucidate underlying molecular mechanisms.

Assessment of dietary cadmium exposure in Sweden and population health concern including scenario analysis

The median dietary cadmium exposure for adults in Sweden is around 1μg/kg/week and the upper 95th and 99th percentiles are 1.6–1.8 and 1.9–2.2μg/kg/week, respectively. Potatoes and wheat flour were the most important food categories, contributing with 40–50% to the exposure. Differences in dietary patterns between high and low exposed individuals were observed; for high exposed individuals, seafood and spinach contributed with an exposure similar to that low exposed individuals received from potatoes and wheat flour. Consequences of differences in methodology used for exposure assessment are discussed. The median exposure is a factor 2 lower compared to that estimated by the European Food Safety Authority (EFSA). It is also a factor 1.4 lower compared to that of the assessment used for development of the EFSA tolerable weekly intake (TWI). The potential importance of this latter fact was addressed by adjusting the present assessment to that used for TWI derivation. While the percentage of the population exceeding the TWI was <1% for the present data, it was around 3% for adjusted data, which is more in line with observations at the level of urinary cadmium. Scenario analysis was also performed to addresses the consequence of increasing/decreasing cadmium occurrence levels.

Response to a commentary by Wiwanitkit (2011) on a report by

1. In our study, clinical specimens were examined by the national laboratory, Thailand Ministry of Public Health (urinary cadmium) and the laboratory of Mae Sot General Hospital (other measurements). The national laboratory has been certified for toxicological analyses in biological materials by the German External Quality Assessment Scheme. The laboratory of the hospital has been certified for clinical chemistry analysis by the National External Quality Assessment Scheme in Clinical Chemistry, Thailand Ministry of Public Health, and by the External Quality Assessment in Clinical Chemistry, Faculty of Medical Technology, Mahidol University. The hospital has also received the national laboratory accreditation. Quality control is mandatory for the measurements by both laboratories. 2. The cadmium-contaminated areas were discovered in the 12 rural villages of the district. We conducted population screening surveys consecutively to determine changes in cadmium exposure using urinary cadmium measurement among inhabitants living in these areas (Swaddiwudhipong et al., 2010). In our health management program, only those with high urinary cadmium levels (Z5 mg/g creatinine) were regularly followed up for chronic cadmium toxicity. Our study included all persons who had urinary cadmium levels Z5 mg/g creatinine and were screened for renal dysfunctions, hypertension, diabetes and urinary stone disease in 2005 (Swaddiwudhipong et al., 2011).

Heavy Metals Exposure and Hearing Loss in US Adolescents

Hearing loss is common and, in young persons, can compromise social development and educational achievement. Exposure to heavy metals has been proposed as an important risk factor for hearing loss. We evaluated the cross-sectional associations between blood lead, blood mercury, and urinary cadmium and arsenic levels and audiometrically determined hearing loss in participants aged 12 to 19 years in the 2005-2008 National Health and Nutrition Examination Survey after accounting for the complex survey design. There were 2535 individuals available for analysis of blood lead and mercury levels, 878 for urinary cadmium levels, and 875 for urinary arsenic levels. Multivariate logistic regression was used to calculate adjusted odds ratios (ORs) and 95% CIs. A blood lead level greater than or equal to 2 μg/dL (to convert to micromoles per liter, multiply by 0.0483) compared with less than 1 μg/dL was associated with increased odds of high-frequency hearing loss (OR, 2.22; 95% CI, 1.39-3.56). Individuals in the highest quartile of urinary cadmium levels had significantly higher odds of low-frequency hearing loss than those in the lowest quartile (OR, 3.08; 95% CI, 1.02-9.25). There was no overall association between quartiles of blood mercury or urinary arsenic levels and hearing loss. Blood lead levels well below the current recommended action level are associated with substantially increased odds of high-frequency hearing loss.

Progress in cadmium-related health effects in persons with high environmental exposure in northwestern Thailand: A five-year follow-up

Food-borne cadmium was the principal source of exposure for persons living in the 12 cadmium-contaminated villages in Mae Sot District, Tak Province, northwestern Thailand. This report presents progress in cadmium-related health effects among persons with high cadmium exposure. The study included 436 persons who had urinary cadmium levels ≥5μg/g creatinine and were screened for urinary cadmium, renal function, hypertension, diabetes and urinary stones in 2005 (baseline) and 2010 (5-year follow-up). Study renal biomarkers included urinary excretion of β2-microglobulin (β2-MG), total protein and calcium, serum creatinine and glomerular filtration rate (GFR). The geometric mean level of urinary cadmium statistically significantly reduced from 9.5±1.6μg/g creatinine in 2005 to 8.8±1.6μg/g creatinine in 2010. Compared to baseline, the follow-up examination revealed significant increases in urinary β2-MG (tubular effect), urinary total protein and serum creatinine, and a decrease in GFR (glomerular effects). Progressive renal dysfunctions were similarly observed in persons both with and without reduction in cadmium intake. Significant increases in prevalence of hypertension, diabetes and urinary stones were also detected at follow-up. These three disorders were found to markedly impair renal functions in the study persons. Our study indicates that in persons with prolonged excessive cadmium exposure, toxic health effects may progress even after exposure reduction. Renal damage from cadmium can be due to its direct nephrotoxic effect and also through the related disorders causing nephropathy.

Human biomonitoring in the Czech Republic: An overview

In the Czech Republic, the Human Biomonitoring Project (CZ-HBM) was launched in 1994 as an integral part of the nationwide Environmental Health Monitoring System (EHMS). Until now, the HBM covers two time periods: the first covered 1994-2003 and the second, 2005-2009. Altogether three population groups were included in the HBM: adults (blood donors aged 18-58 years), children aged 8-10 years, and breastfeeding primiparas. Sampling is organized on a yearly basis. Altogether three groups of biomarkers were analyzed: (a) selected heavy metals (Pb, Cd, Hg) and essential elements (Cu, Se, Zn) in blood and urine of adults and children, (b) indicator PCBs, DDT, DDE, HCB and HCHs in human milk and blood serum of adults and (c) cytogenetic changes in peripheral lymphocytes in blood of adults and children. This paper is focused on the general design of the CZ-HBM, the trends over time, and reference values. A significant downward time trend was observed for the blood lead levels in adults and children. Increased urinary cadmium levels were observed in Czech children compared to German children. The blood and urinary mercury levels were higher in women than in men. The levels of indicator PCB congeners in the Czech human milk samples were still higher than in most other European countries, because of existing hot spots. The levels of organochlorine pesticides showed a substantial continuous downward trend.

Cadmium-induced renal tubular dysfunction in a group of welders

Occupational exposure to welding fumes has been associated with several diseases including metal fume fever, lung cancer, welder's pneumoconiosis and manganism. However, there are few reports on cadmium-induced renal tubular dysfunction in welders. To evaluate the body burden of cadmium and cadmium-induced proteinuria in a group of Chinese welders. Cadmium concentrations in the breathing zone and in urine were measured by atomic absorption spectrometry. β(2)-microglobulin (β(2)-MG) in urine as a marker of renal tubular function was measured using an ELISA kit. All urinary parameters were adjusted by urinary creatinine (Cr). A total of 103 welders participated. The concentration of airborne cadmium in the welders' breathing zones ranged from 5 to 86 μg/m(3), and 17% of samples exceeded the threshold limit value. Six welders' urinary cadmium levels exceeded the Chinese recommended reference value. Urinary β(2)-MG levels increased significantly with increasing urinary cadmium levels and in two welders, the values were close to the level for chronic cadmium poisoning in China. Environmental and urinary cadmium levels were raised in this group of welders and were associated with raised markers of renal tubular dysfunction. The exact source of the cadmium warrants further assessment.

Cadmium Exposure and Kidney Stone Formation in the General Population—An Analysis of the National Health and Nutrition Examination Survey III Data

Cadmium exposure has been associated with a greater risk of kidney stone formation in occupational exposure studies, but data on such an association in the general population are scarce. We assessed the National Health and Nutrition Examination Survey data from 1988 to 1994 in terms of the risk of stone formation. Persons reporting a history of kidney stones were defined as stone formers (n=749), and the association between a positive history of kidney stones and high environmental cadmium exposure levels (defined as urinary cadmium >1 μg/g) was analyzed by logistic regression analysis, stratifying by sex and adjusting for age, race/ethnicity, body mass index, smoking habits, region of residence, and daily intake of calcium and sodium. The odds ratio of lithiasis associated with urinary cadmium >1 μg/g was 1.40 (95% confidence interval 1.06, 1.86) in females (P = 0.019). The association between urinary cadmium and kidney stones was not significant in males. These findings suggest that moderately high levels of urinary cadmium are associated with a greater propensity for kidney stone formation in females in the general population.

Bone mineral density is related with previous renal dysfunction caused by cadmium exposure

Relationship between bone mineral density (BMD) and previous renal dysfunction caused by cadmium exposure was investigated. A total of 457 persons, living in polluted and control areas, were followed up in this study. The inhabitants living in exposure areas ceased ingesting cadmium-contaminated rice in 1996. Blood and urinary cadmium levels and BMD in 1998 and 2006 were measured. Urinary N-acetyl- β- d-glucosaminidase and albumin determined in 1998 and 2006 were used to evaluate kidney status. BMD of subjects with tubular damage was significant lower than those without damage in female ( p < 0.05). The prevalence of osteoporosis was significantly different between those with and without kidney damage ( p = 0.003, in total population; p = 0.039, in female) and those with and without tubular damage ( p = 0.0005, in total population; p = 0.007, in female). The results suggested that BMD was correlated with previous kidney impairment caused by cadmium exposure, especially to tubular damage and especially for female.

Erratum: "A Biomonitoring Study of Lead, Cadmium, and Mercury in the Blood of New York City Adults".

[This corrects the article DOI: 10.1289/ehp.10056.].

Reversed association between levels of prostate specific antigen and levels of blood cadmium and urinary cadmium

Prostate cancer associated with cadmium exposure may indicate a link between prostate specific antigen (PSA) and levels of blood cadmium (BCd) and urinary cadmium (UCd). Thus, these associations were investigated. We recruited 295 men, 50 years of age and above from a health check-up program at a health center as subjects of the study. They completed a self-reported questionnaire and provided fasting samples of blood and urine for cadmium assay. The assay was performed using atomic absorption spectrophotometry. Blood samples were also collected for the assays of total cholesterol and high-density lipoprotein measures. The means of BCd and UCd increased with age and the means of all subjects were 1.19 ± 1.04 μg L −1 and 1.37 ± 1.76 μg g −1 creatinine, respectively. The PSA levels were positively associated with the lipid levels, but reversely associated with BCd and UCd levels. The multivariate logistic regression analysis showed that men with PSA ⩾ 4.0 ng mL −1 had an odds ratio (OR) of 0.4 (95% CI = 0.1–0.9) to have BCd > 0.49 μg L −1, and an OR of 0.4 (95% CI = 0.2–1.0) to have UCd > 0.45 μg g −1 creatinine. In conclusion, the PSA levels are reversely associated with BCd and UCd levels.

An association between urinary cadmium and urinary stone disease in persons living in cadmium-contaminated villages in northwestern Thailand: A population study

Excessive urinary calcium excretion is the major risk of urinary stone formation. Very few population studies have been performed to determine the relationship between environmental cadmium exposure and urinary stone disease. This population-based study examined an association between urinary cadmium excretion, a good biomarker of long-term cadmium exposure, and prevalence of urinary stones in persons aged 15 years and older, who lived in the 12 cadmium-contaminated villages in the Mae Sot District, Tak Province, northwestern Thailand. A total of 6748 persons were interviewed and screened for urinary cadmium and urinary stone disease in 2009. To test a correlation between urinary excretion of cadmium and calcium, we measured urinary calcium content in 1492 persons, who lived in 3 villages randomly selected from the 12 contaminated villages. The rate of urinary stones significantly increased from 4.3% among persons in the lowest quartile of urinary cadmium to 11.3% in the highest quartile. An increase in stone prevalence with increasing urinary cadmium levels was similarly observed in both genders. Multiple logistic regression analysis revealed a positive association between urinary cadmium levels and stone prevalence, after adjusting for other co-variables. The urinary calcium excretion significantly increased with increasing urinary cadmium levels in both genders, after adjusting for other co-variables. Elevated calciuria induced by cadmium might increase the risk of urinary stone formation in this environmentally exposed population.

The Effect of Exposure Factors on the Concentration of Heavy Metals in Residents Near Abandoned Metal Mines

This study assessed the factors that have an influence on the residents exposed to heavy metals, and we utilized the findings to establish the proper management of abandoned metal mines in the future. For a total of 258 residents who lived close to abandoned mines in Gangwon-province and Gyeonggi-province, the exposure factors and biomarkers in their blood and urine were comparatively analyzed via multiple regression analysis. The blood levels of lead and mercury and the cadmium levels in urine were found to be higher in the study group than that in the average Korean. For the blood levels of heavy metals according to each exposure factor, all of them were found to be significantly higher in both of the group residing for a longer period of time and the group living closer to the source of pollutants. Multiple regression analysis disclosed that all the heavy metals, except lead, in their blood were significantly reduced in proportion to the increased distance of inhabitancy from the mines. Their other biomarkers were within the normal ranges. We found that the distance between the residential village and the mines was a factor that affects the blood level of heavy metals in the villagers. This finding could be an important factor when developing a management model for the areas that surround abandoned metal mines. (ED note: I much like this important study.).