Biological monitoring of exposure to cadmium, a human carcinogen, as a result of active and passive smoking

Association of environmental tobacco smoke (ETS) with lead and cadmium concentrations in biological samples of children and women: systematic review and meta-analysis

OBJECTIVES

Previous literature has shown that heavy metals (HMs) in cigarette smoke have been overestimated, and second-hand smoke (SHS) has recently raised public concern. This study aimed to review the effects of passive tobacco exposure on lead (Pb) and cadmium (Cd) concentrations of children and women in different biological samples.

CONTENT

In this systematic review, two independent researchers assessed different databases/search engines including PubMed, Web of Science, Scopus, and Google Scholar using Mesh terms and Text Words. Studies between January 2000 and May 2022 were included. After quality assessment, studies with sufficient data were included in the meta-analysis. A fixed or random model was used to pool the results in a meta-analysis. Heterogeneity between the studies was assessed by using I-square and Q tests. Forest plots demonstrating the point and pooled estimates were provided.

SUMMARY

A total of 976 studies were obtained from different databases and finally 17 studies meet our criteria and were included in our systematic review. Out of 17 studies, six studies had sufficient data for analysis and were included in the meta-analysis. The results of the meta-analysis showed a significant difference in blood lead concentrations (BLC) between the children with SHS exposure and the control group (Hedges' g: 2.44, 95% CI: 1.01-3.86, p<0.05). Also, there were significant differences in hair levels of Cd (Hedges' g: 0.66, 95% CI: 0.04, 1.28, p<0.05) and Pb (Hedges' g: 0.94, 95% CI: 0.05, 1.83, p<0.05) between children with SHS exposure compared to the control group.

OUTLOOK

The results of the present meta-analysis showed that passive smokers had higher Pb and Cd concentrations than those who were not exposed to cigarette smoke.

Dietary cadmium induced declined locomotory and reproductive fitness with altered homeostasis of essential elements in Drosophila melanogaster

Cadmium (Cd) exerts detrimental effects on multiple biological processes of the living organisms along with epigenetic transgenerational effect. Drosophila melanogaster offers unique opportunity to evaluate Cd toxicity when studying important life traits in short duration of time by designing distinct behavioural assays. Present study utilized this model organism to assess Cd induced lethality, retarded growth, decreased life span and altered behaviour of the animals either at larval or adult stage. Our investigations revealed reduced locomotion and reproductive fitness of the animals upon Cd exposure. Transgenerational effect on locomotion was found to be behaviour specific as larval crawling was affected, but adult fly negative geotaxis was comparable to the control. Mechanistically, decreased antioxidant enzymes activity, superoxide dismutase (SOD) and catalase (CAT) together with altered homeostasis of essential elements (Fe, Zn and Mg) may be responsible for the observed effects. Altogether our work showed extensive range of Cd altered Drosophila behaviour which warrants need to control environmental Cd toxicity.

Mercury Is Taken Up Selectively by Cells Involved in Joint, Bone, and Connective Tissue Disorders

Background: The causes of most arthropathies, osteoarthritis, and connective tissue disorders remain unknown, but exposure to toxic metals could play a part in their pathogenesis. Human exposure to mercury is common, so to determine whether mercury could be affecting joints, bones, and connective tissues we used a histochemical method to determine the cellular uptake of mercury in mice. Whole neonatal mice were examined since this allowed histological assessment of mercury in joint, bone, and connective tissue cells. Materials and Methods: Pregnant mice were exposed to a non-toxic dose of 0.5 mg/m3 of mercury vapor for 4 h a day on gestational days 14-18. Neonates were sacrificed at postnatal day 1, fixed in formalin, and transverse blocks of the body were processed for paraffin embedding. Seven micrometer sections were stained for inorganic mercury using silver nitrate autometallography, either alone or combined with CD44 immunostaining to detect progenitor cells. Control neonates were not exposed to mercury during gestation. Results: Uptake of mercury was marked in synovial cells, articular chondrocytes, and periosteal and tracheal cartilage cells. Mercury was seen in fibroblasts in the dermis, aorta, esophagus and striated muscle, some of which were CD44-positive progenitor cells, and in the endothelial cells of small blood vessels. Mercury was also present in renal tubules and liver periportal cells. Conclusions: Mercury is taken up selectively by cells that are predominantly affected in rheumatoid arthritis and osteoarthritis. In addition, fibroblasts in several organs often involved in multisystem connective tissue disorders take up mercury. Mercury provokes the autoimmune, inflammatory, genetic, and epigenetic changes that have been described in a range of arthropathies and bone and connective tissue disorders. These findings support the hypothesis that mercury exposure could trigger some of these disorders, particularly in people with a genetic susceptibility to autoimmunity.

Blood Cadmium Concentrations in Women with Ectopic Pregnancy

The purpose of this study is to investigate the relationship between the blood level of cadmium and the occurrence of ectopic pregnancy. Forty-one (41) case patients with ectopic pregnancy and 41 uncomplicated intrauterine pregnant patients as controls were recruited. The concentrations of cadmium (Cd) were measured from blood samples using atomic absorption spectrometry. The cases and controls were similar in age, body mass index, and smoking habits. The median blood level of Cd was 0.32 μg/l (interquartile range [IQR] 0.00-0.71) in the women with ectopic pregnancies and 0.34 μg/l (IQR 0.09-0.59) in the controls. There was no significant association between blood cadmium levels and ectopic pregnancy.

Cadmium Body Burden and Gestational Diabetes Mellitus: A Prospective Study

BACKGROUND

Several studies have reported that cadmium (Cd) is associated with type 2 diabetes. However, little is known about Cd exposure and the risk of gestational diabetes mellitus (GDM).

OBJECTIVE

We examined the association between Cd body burden in early pregnancy and the risk of GDM.

METHODS

We conducted a prospective study of 2,026 pregnant women from a single tertiary medical center between 2013 and 2016 in Wuhan, China. Cd body burden was reflected by Cd concentrations in urine samples collected between gestational weeks 8 and 14. GDM was diagnosed according to International Association of Diabetes and Pregnancy Study Groups Consensus Panel (IADPSG) recommendations.

RESULTS

The geometric mean of Cd concentrations in maternal urine of all pregnant women was 0.59μg/L. A total of 198 (9.8%) women were diagnosed with GDM. After adjustment for potential confounders, the risk ratios (RRs) of GDM were 1.04 (95% CI: 0.74, 1.44) for the middle tertile of Cd levels and 1.36 (95%: CI: 0.98, 1.90) for the top tertile compared with the bottom tertile. In addition, we found a significant interaction between fetal sex and maternal Cd levels on the risk of GDM (p for interaction=0.03). Among women carrying male fetuses, the RR of GDM was 1.86 (95% CI: 1.14, 2.93) for the top tertile of Cd levels compared with the bottom tertile.

CONCLUSIONS

To our knowledge, this is the first report of an association between urinary Cd levels in early pregnancy and GDM. Our findings suggest that Cd body burden increases the risk of GDM and that the association may be modified by fetal sex. https://doi.org/10.1289/EHP2716.

A morphological study of uterine alterations in mice due to exposure to cadmium

We investigated the morphologic and molecular effects of exposure to cadmium (Cd) for 30 and 60 days on the uteri of mice. We assessed uterine morphometric measurements, eosinophilia, mast cell numbers, endometrial apoptosis, proliferation and estrogen receptor alpha (ERα) immunoreactivity. We examined vaginal smears that reflected the hormonal alterations in the female reproductive tract. Because the female reproductive tract exhibits different morphology at each stage of the estrous cycle, we sacrificed all animals at estrus to make appropriate comparisons. Female BALB/c mice were exposed to 200 ppm Cd in their drinking water for either 30 or 60 days. Cd exposure caused significant decreases in endometrial thickness and number of glands in estrus phase uteri. The endometrial eosinophilia in the groups exposed to Cd also decreased compared to controls. Cd exposure increased the number of mast cells. Luminal and glandular epithelia were examined using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and by immunostaining proliferating cell nuclear antigen (PCNA) and estrogen receptor α (ERα). Compared to controls, the apoptotic index increased with time in both Cd exposed groups, while the proliferation index decreased. ERα immunoreactivity was decreased in both Cd exposed groups compared to controls; the decrease was most apparent in the 30 day Cd group. We found that 60 day Cd exposure increased apoptosis in the endometrium, which may affect the receptivity of the uterus for implantation.

Predictors of cadmium and lead concentrations in the blood of residents from the metropolitan area of Athens (Greece)

The Cd and Pb blood contents of healthy adult subjects who are non-occupationally exposed and living in the metropolitan area of Athens (Greece) have not been assessed thus far. Additionally, Greeks rank first among EU27 in terms of smoking habits. To fill the existing gap, we aimed to evaluate the predictors and propose reference values (RVs) of the Cd (CdB) and Pb (PbB) blood concentrations in residents of the metropolitan area of Athens (Greece). Age, sex, smoking, alcohol drinking, educational status and nutritional habits were used as variables, with an emphasis on smoking. CdB and PbB determinations were performed directly by graphite furnace atomic absorption spectrometry (GFAAS) following the appropriate dilution of the samples with Triton-X-100. The RVs of CdB and PbB proposed for the general adult population of the Metropolitan area of Athens, Greece (upper limit of the 95% CI of the 95th percentile of the distribution of values), were 2.3 and 88μgL(-1) (P95: 1.8 and 77μgL(-1); 95% CI (P95): 1.5-2.3 and 70-88μgL(-1)), respectively. Males had a higher median CdB (0.69μgL(-1)) than females (0.55μgL(-1)). Subjects aged <40years had a lower median CdB (0.51μgL(-1)) than the elderly (≥60years; 0.60μgL(-1)). The CdB in smokers (1.2μgL(-1)) was almost threefold higher than in non-smokers (0.46μgL(-1)). The PbB levels were higher in males (31μgL(-1)) than females (20μgL(-1)). Subjects aged <40years had a lower median PbB (17μgL(-1)) than the elderly (≥60years; 32μgL(-1)). A multiple linear regression analysis demonstrated that the predictor variables for the CdB levels were the standardized beta weight, smoking, age, alcohol consumption, and intake of leafy vegetables, whereas for the PbB levels they were sex and age.

Determinants of serum cadmium levels in a Northern Italy community: A cross-sectional study

INTRODUCTION

Cadmium (Cd) is a heavy metal and a serious environmental hazard to humans. Some uncertainties still exist about major sources of Cd exposure in non-occupationally exposed subjects in addition to cigarette smoking, such as diet and outdoor air pollution. We sought to determine the influence of these sources on a biomarker of exposure, serum Cd concentration.

METHODS

We recruited 51 randomly selected residents from an Italian urban community, from whom we obtained detailed information about dietary habits and smoking habits, and a blood sample for serum Cd determination. We also assessed outdoor air Cd exposure, by modeling outdoor air levels of particulate matter ≤10µm (PM10) from motorized traffic at geocoded subjects' residence.

RESULTS

In crude analysis, regression beta coefficients for dietary Cd, smoking and PM10 on serum Cd levels were 0.03 (95% CI -0.83 to 0.88), 6.96 (95% CI -0.02 to 13.95) and 0.62 (95% CI -0.19 to 1.43), respectively. In the adjusted analysis, regression beta coefficients were -0.34 (95% CI -1-40 to 0.71), 5.81 (95% CI -1.43 to 13.04) and 0.47 (95% CI -0.35 to 1.29), respectively.

CONCLUSION

Cigarette smoking was the most important factor influencing serum Cd in our non-occupationally exposed population, as expected, while dietary Cd was not associated with this biomarker. Outdoor air pollution, as assessed through exposure to particulate matter generated by motorized traffic, was an additional source of Cd exposure.

Neurotoxicants, Micronutrients, and Social Environments

SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants.

In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition.

Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc.

Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients.

Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning.

We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.

Association between secondhand smoke exposure and blood lead and cadmium concentration in community dwelling women: the fifth Korea National Health and Nutrition Examination Survey (2010-2012)

OBJECTIVES

To assess the association between secondhand smoke exposure and blood lead and cadmium concentration in women in South Korea.

DESIGN

Population-based cross-sectional study.

SETTING

South Korea (Korea National Health and Nutrition Examination Survey V).

PARTICIPANTS

1490 non-smoking women who took part in the fifth Korea National Health and Nutrition Examination Survey (2010-2012), in which blood levels of lead and cadmium were measured.

PRIMARY OUTCOME MEASURES

The primary outcome was blood levels of lead and cadmium in accordance with the duration of secondhand smoke exposure.

RESULTS

The adjusted mean level of blood cadmium in women who were never exposed to secondhand smoke was 1.21 (0.02) µg/L. Among women who were exposed less than 1 h/day, the mean cadmium level was 1.13 (0.03) µg/L, and for those exposed for more than 1 h, the mean level was 1.46 (0.06) µg/L. In particular, there was a significant association between duration of secondhand smoke exposure at the workplace and blood cadmium concentration. The adjusted mean level of blood cadmium concentration in the never exposed women's group was less than that in the 1 h and more exposed group, and the 1 h and more at workplace exposed group: 1.20, 1.24 and 1.50 µg/L, respectively. We could not find any association between lead concentration in the blood and secondhand smoke exposure status.

CONCLUSIONS

This study showed that exposure to secondhand smoke and blood cadmium levels are associated. Especially, there was a significant association at the workplace. Therefore, social and political efforts for reducing the exposure to secondhand smoke at the workplace are needed in order to promote a healthier working environment for women.

Anti-smoking legislation and its effects on urinary cotinine and cadmium levels

Anti-smoking legislation has been associated with an improvement in health indicators. Since the cadmium (Cd) body burden in the general population is markedly increased by smoke exposure, we analyzed the impact of the more restrictive legislation that came into force in Spain in 2011 by measuring Cd and cotinine in first morning urine samples from 83 adults in Madrid (Spain) before (2010) and after (2011) introduction of this law. Individual pair-wise comparisons showed a reduction of creatinine corrected Cotinine and Cd levels for non-active smokers, i. e. those which urinary cotinine levels are below 50 μg/L. After the application of the stricter law, cotinine levels in urine only decreased in non-active smokers who self-reported not to be exposed to second-hand smoke. The reduction in second hand smoke exposure was significantly higher in weekends (Friday to Sunday) than in working days (Monday to Thursday). The decrease in U-Cd was highly significant in non-active smokers and, in general, correlated with lower creatinine excretion. Therefore correction by creatinine could bias urinary Cd results, at least for cotinine levels higher than 500 μg/L. The biochemical/toxicological benefits detected herein support the stricter application of anti-smoking legislation and emphasize the need to raise the awareness of the population as regards exposure at home.

Cigarette smoke cadmium breakthrough from traditional filters: implications for exposure

Cadmium, a carcinogenic metal, is highly toxic to renal, skeletal, nervous, respiratory and cardiovascular systems. Accurate and precise quantification of mainstream smoke cadmium levels in cigarette smoke is important because of exposure concerns. The two most common trapping techniques for collecting mainstream tobacco smoke particulate for analysis are glass fiber filters and electrostatic precipitators. We observed that a significant portion of total cadmium passed through standard glass fiber filters that are used to trap particulate matter. We therefore developed platinum traps to collect the cadmium that passed through the filters and tested a variety of cigarettes with different physical parameters for quantities of cadmium that passed though the filters. We found <1% cadmium passed through electrostatic precipitators. In contrast, cadmium that passed through 92 mm glass fiber filters on a rotary smoking machine was significantly higher, ranging from 3.5 to 22.9% of total smoke cadmium deliveries. Cadmium passed through 44 mm filters typically used on linear smoking machines to an even greater degree, ranging from 13.6 to 30.4% of the total smoke cadmium deliveries. Differences in the cadmium that passed through from the glass fiber filters and electrostatic precipitator could be explained in part if cadmium resides in the smaller mainstream smoke aerosol particle sizes. Differences in particle size distribution could have toxicological implications and could help explain the pulmonary and cardiovascular cadmium uptake in smokers.

The association between blood cadmium level and airflow obstruction in Korean men

BACKGROUND

Most humans are exposed to environmental contaminants via inhalation. Various toxic inhalants cause lung damage with pathologic changes to the airway system. Lung function decline is an important cause of morbidity and mortality worldwide.

AIM

To consider the potential burden of cadmium on pulmonary disease, this study examined the relationship between blood cadmium levels and airflow obstruction in a Korean general population.

SUBJECTS AND METHODS

Data from the Korean National Health and Nutrition Examination Surveys from 2008-2011 were used. Male participants were selected who were older than 40 years, who had completed a reliable pulmonary function test and for who measurements of blood cadmium levels were available (n = 1974). The pulmonary function tests were undertaken and airflow obstruction was defined when forced vital capacity/forced expiratory volume in 1 second ratio < 0.7.

RESULTS

In an age-adjusted logistic regression model, blood cadmium levels correlated with the risk of obstructive airflow pattern in total participants as well as in smokers or never smokers. Further adjustment for BMI, current occupation and educational level did not attenuate these associations among total participants, smokers and never smokers (OR = 2.53, 95% CI = 1.83-3.50 in total; OR = 2.17, 95% CI = 1.55-3.02 in smokers; OR = 3.71, 95% CI = 1.48-9.33 in never smokers).

CONCLUSIONS

In conclusion, blood cadmium level was associated with airflow obstruction independently of smoking history and that association was still significant in never smokers. Careful attention is needed for the general population who are potentially exposed to cadmium.

Blood lead, cadmium and mercury among children from urban, industrial and rural areas of Fez Boulemane Region (Morocco): relevant factors and early renal effects

OBJECTIVES

To describe blood lead (Pb-B), cadmium (Cd-B) and mercury (Hg-B) levels in children living in urban, industrial and rural areas in Fez city (north of Morocco) and to identify the determinants and some renal effects of exposure.

MATERIAL AND METHODS

The study was conducted from June 2007 to January 2008 in 209 school children (113 girls, 96 boys), aged 6-12 years, from urban, industrial and rural areas in Fez city. Interview and questionnaires data were obtained. Blood and urinary samples were analyzed.

RESULTS

The mean of blood lead levels (Pb-B) in our population was 55.53 μg/l (range: 7.5-231.1 μg/l). Children from the urban area had higher blood lead levels (BLLs) mean (82.36 μg/l) than children from industrial and rural areas (48.23 and 35.99 μg/l, respectively); with no significant difference between boys and girls. BLLs were associated with traffic intensity, passive smoking and infancy in the urban area. The mean of blood cadmium levels (BCLs) was 0.22 μg/l (range: 0.06-0.68 μg/l), with no difference between various areas. Rural boys had higher BCLs mean than rural girls, but no gender influence was noticed in the other areas. BCLs were associated with the number of cigarettes smoked at children's homes. The blood mercury levels (BMLs) mean was 0.49 μg/l (range: 0.01-5.31 μg/l). The BMLs mean was higher in urban and industrial areas than in the rural area with no gender-related difference. BMLs were associated with amalgam fillings and infancy in the urban area. About 8% of the children had BLLs ≥ 100 μg/l particularly in the urban area, microalbuminuria and a decrease in height were noticed in girls from the inner city of Fez and that can be related to high BLLs (89.45 μg/l).

CONCLUSIONS

There is a need to control and regulate potential sources of contamination by these trace elements in children; particularly for lead.

Blood levels of lead, cadmium, and mercury in the elderly living in institutionalized care in the Czech Republic

BACKGROUND

There is limited research examining the chemical load of toxic metals in the elderly. The aim of the present study was two-fold: to determine the body burden of lead, cadmium and mercury in association with age, gender, locality, lifestyle factors and potential health impacts among this population and to compare the values with blood values from the general Czech population aged 18-64 years.

METHODS

Lead, cadmium and mercury were examined in the blood of institutionalized senior citizens (46 males, 151 females aged 61-100 years) from two localities in the Czech Republic (Prague and Teplice) from 2009 through 2011. Measurements were made using inductively coupled plasma mass spectrometry (Pb, Cd) and a single purpose spectrometer AMA 254 (Hg).

RESULTS

Geometric means (GM) of whole blood lead (B-Pb), cadmium (B-Cd) and mercury (B-Hg) levels were 25.3μg/l, 0.55μg/l and 0.21μg/l, respectively. No age-related differences were found for B-Pb and B-Cd levels but a negative correlation with age was observed for B-Hg levels (p=0.04). B-Pb levels in men were significantly higher than in women (GM 29.9μg/l vs. 24.1μg/l). B-Cd was significantly higher in women (GM 0.57μg/l) than in men (0.50μg/l) (p=0.007) and in smokers (GM 1.29μg/l) than in nonsmokers (GM 0.53μg/l) (p=<0.001) and in seniors from Prague (GM 0.60μg/l) compared to those from Teplice (GM 0.43μg/l) (p=<0.001). Seniors with a history of chronic kidney disease, stroke and those using psycho-pharmaceuticals had higher B-Pb levels (p=0.008, 0.04 and 0.05, resp.), seniors diagnosed with atherosclerosis had higher B-Cd levels (p=0.002) and seniors using psycho-pharmaceuticals had higher B-Hg levels (p=0.07). B-Hg levels were also positively correlated with blood albumin levels (p=0.015).

CONCLUSIONS

This study provides data on levels of heavy metals in a group of elderly people. Such information is very scarce. Associations with diseases should be the subject of further investigation.

Cadmium blood and urine concentrations as measures of exposure: NHANES 1999-2010

Exposure to cadmium, a heavy metal present in cigarettes, can be assessed in both urine and blood. Few studies have compared the properties of concurrent measurements of urine cadmium (uCd) and blood cadmium (bCd) in relation to the duration and timing of a known exposure. In this study, bCd and uCd were modeled with data from the National Health and Nutrition Examination Survey (1999-2010). Adjusted geometric mean bCd and uCd were estimated from regression results. Each 1% higher geometric mean uCd was associated with 0.50% (95% confidence interval: 0.47%-0.54%; R(2)=0.30) higher bCd. In male never-smokers, bCd was 69% (59%-81%) and uCd was 200% (166%-234%) higher at age ≥70 years versus 20-29 years. Ten pack-years (py) of smoking were associated with 13.7% (10.0%-17.4%) higher bCd and 16.8% (12.6%-21.1%) higher uCd in male smokers. The first year after smoking cessation was associated with 53% (48%-58%) lower bCd and 23% (14%-33%) lower uCd in representative males aged 55 years with 20 py smoking. Smoking in the previous 5 days was associated with 55% (40%-71%) higher bCd and 7% (-3%-18%) higher uCd. Results were similar for women. uCd mainly measures long-term exposure and bCd recent exposure, but with noticeable overlap. Epidemiological studies should base the choice of uCd or bCd on the timing of cadmium exposure relevant to the disease under study.

Relationship between passive smoking exposure and urinary heavy metals and lung functions in preschool children

Environmental tobacco smoke (ETS) exposure is a risk factor for asthma in school-age children, but there is limited data of ETS exposure on respiratory health in preschool children. This study investigated the relationship between ETS, lead (Pb), and cadmium (Cd) exposures and asthma symptoms and spirometric indices in Chinese preschoolers. Preschool children from 30 nurseries and kindergartens performed spirometry with incentives of animation programs, and their urinary cotinine, Pb and Cd concentrations were measured by immunoassay and inductively coupled plasma-mass spectrometry, respectively. Two thousand seven hundred sixty-three preschoolers participated, and 1,505 and 893 provided valid spirometric data and urine samples, respectively. Current domestic smoking was reported in 37.5% of children, but only 95 (10.6%) had high urinary cotinine-to-creatinine ratio (≥30 ng/mg). Pb was measurable in 3.9% of samples, whereas 406 (45.5%) children had high Cd. Reported ETS exposure was not associated with any spirometric index, whereas cotinine-to-creatinine ratio was inversely associated with forced expiratory volume in 0.5-sec (β = -0.093, P = 0.003), forced expiratory flow between 25% and 75% of expiration (β = -0.138, P = 0.002) and peak expiratory flow (β = -0.106, P = 0.002). Cd exposure was not associated with reported respiratory symptom or spirometric indices. This community study shows that ETS exposure defined by urinary cotinine is a strong risk factor for lung function impairment measured by spirometry in Chinese preschool children. Urinary cotinine is more reliable than questionnaire for assessing ETS exposure in young children. Although high urinary Cd is common in Hong Kong preschoolers, such biomarker is not associated with any clinical or spirometric outcome.

Hypothesis: cadmium explains, in part, why smoking increases the risk of cardiovascular disease

INTRODUCTION

Cigarette smoking is a major risk factor for cardiovascular disease via acute and chronic mechanisms, some of which remain unclear. One plausible but untested hypothesis concerns cadmium (Cd), a component of cigarette smoke, which is injurious to vascular endothelial cells and is independently associated with cardiovascular disease. To contribute to the formulation of this hypothesis, we performed a meta-analysis of the available data that consisted of cross-sectional studies useful to formulate but not test hypotheses.

METHODS

PubMed and Google Scholar were searched by combining the terms smoking, Cd, correlation, blood, human, and tobacco. Following abstract review, 10 cross-sectional studies were identified. We compared serum Cd levels between smokers and nonsmokers using standardized mean differences (SMDs) as well as correlation coefficients between smoking and Cd.

RESULTS

The estimated overall random effects SMD in Cd between smokers and nonsmokers was 1.13 (95% confidence interval [CI], .70-1.56) with significant heterogeneity (Q = 8.6, P < .001). The estimated overall random effects correlation coefficient between smoking and Cd was .54 (95% CI, .30-.72) with significant heterogeneity (Q = 71.3, P < .01).

CONCLUSIONS

Despite major inherent limitations of meta-analyses of cross-sectional studies, we believe that the data contribute to the formulation of the hypothesis that Cd explains, in part, why smokers have an increased risk of cardiovascular disease. Further research, including analytic studies designed a priori are necessary to test the hypothesis.

Cadmium exposure and tobacco consumption: Biomarkers and risk assessment

To investigate whether cadmium has an independent role in diseases associated with tobacco consumption, epidemiology data were reviewed, biomonitoring data were analyzed, and probabilistic risk assessment (PRA) was performed. Results from previous epidemiology studies have indicated that there are adverse health effects potentially in common between cadmium exposure and tobacco consumption. Analysis of publically available biomonitoring data showed that blood (B-Cd) and urine (U-Cd) cadmium were higher in cigarette smokers compared with smokeless tobacco (SLT) consumers, and B-Cd and U-Cd in SLT consumers were not significantly different than in non-consumers of tobacco. Comparison with previously established biomonitoring equivalent (BE) values indicated that B-Cd and U-Cd in the majority of these cigarette smokers and SLT consumers did not exceed the blood and urine BEs. Results of the PRA showed that the mean hazard estimate was below a generally accepted regulatory threshold for SLT consumers, but not for cigarette smokers. In total, this evaluation indicated that cadmium exposures in tobacco consumers differed by product category consumed; cadmium in tobacco may not be associated with tobacco consumption related diseases; if cadmium in tobacco contributes to tobacco consumption related diseases, differences in hazard and/or risk may exist by product category.

Levels of heavy metals in popular cigarette brands and exposure to these metals via smoking

The levels of selected heavy metals in popular cigarette brands sold and/or produced in Saudi Arabia were determined by graphite furnace-atomic absorption spectrometry (GFAAS). Average concentrations of Cadmium and Lead in different cigarette brands were 1.81 and 2.46 μg g⁻¹ (dry weight), respectively. The results obtained in this study estimate the average quantity of Cd inhaled from smoking one packet of 20 cigarettes to be in the range of 0.22-0.78 μg. Results suggest that the quantity of Pb inhaled of smoking one packet of 20 cigarettes is estimated to be 0.97-2.64 μg. The concentrations of Cd and Pb in cigarettes were significantly different between cigarette brands tested. The results of the present study were compared with those of other regional and international studies.

Diet and nutrients are contributing factors that influence blood cadmium levels

Studies suggested the intake of Cd from diet can be approximately equivalent to that from smoking. Moreover, a mutual metabolic influence between Cd and nutrients has been reported. The purpose of this study was to evaluate the relationship between blood cadmium concentration (BCdC) and food consumption, nutrients intake (Ca, Fe, Zn, vitamin C, and vitamin D), tobacco smoking, and some other variables (age, body mass index, and residence) in 243 adults living in the Italian island of Sardinia (Sassari Province). Specifically, we hypothesized that offal consumption contributes to Cd intakes and blood levels. The BCdC was quantified by graphite furnace atomic absorption spectrometry, and information on personal data was collected through questionnaires. Smoke significantly contributed to the BCdC (P < .001). Nonsmoker subjects who eat offal showed significantly higher BCdC (P = .04). Moreover, slightly higher BCdCs were also observed in nonsmoker subjects who eat rice, fish, and bread. The BCdC positively correlated with age of subjects (r = 0.144; P = .025) and offal daily intake in nonsmokers (r = 0.393; P < .001). The intake of Ca was negatively correlated (r = -0.281; P = .001) with the BCdC in females. The multiple linear regression analysis showed smoking > consumption of offal > body mass index ≈ age as the most important risk factors for the BCdC in the selected population.

Toxic elements in tobacco and in cigarette smoke: inflammation and sensitization

Biochemically and pathologically, there is strong evidence for both atopic and nonatopic airway sensitization, hyperresponsiveness, and inflammation as a consequence of exposure to tobacco mainstream or sidestream smoke particulate. There is growing evidence for the relation between exposure to mainstream and sidestream smoke and diseases resulting from reactive oxidant challenge and inflammation directly as a consequence of the combined activity of neutrophils, macrophages, dendritic cells, eosinophils, basophils, as a humoral immunological consequence of sensitization, and that the metal components of the particulate play a role in adjuvant effects. As an end consequence, carcinogenicity is a known outcome of chronic inflammation. Smokeless tobacco has been evaluated by the IARC as a group 1 carcinogen. Of the many harmful constituents in smokeless tobacco, oral tissue metallothionein gradients suggest that metals contribute to the toxicity from smokeless tobacco use and possibly sensitization. This work reviews and examines work on probable contributions of toxic metals from tobacco and smoke to pathology observed as a consequence of smoking and the use of smokeless tobacco.

Differential exposure biomarker levels among cigarette smokers and smokeless tobacco consumers in the National Health and Nutrition Examination Survey 1999-2008

Assessment of biomarkers is an appropriate way to estimate exposure to cigarette mainstream smoke and smokeless tobacco (SLT) constituents in tobacco consumers. Using the US National Health and Nutrition Examination Survey (NHANES, 1999-2008), biomarkers of volatile organic compounds, halogenated aromatic hydrocarbons (HAHs), polycyclic aromatic hydrocarbons (PAHs), acrylamide, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and metals were evaluated. In general, biomarker levels in SLT consumers were significantly lower than in smokers (excluding NNK and some HAHs) and were not significantly different compared with nonconsumers (excluding NNK and some PAHs). These results provide useful information for science-based risk assessment and regulation of tobacco products.

Effects of cigarette smoking on reproduction

BACKGROUND Cigarette smoking is associated with lower fecundity rates, adverse reproductive outcomes and a higher risk of IVF failures. Over the last few decades, prevalence of smoking among women of reproductive age has increased. This review focuses on current knowledge of the potential effects of smoke toxicants on all reproductive stages and the consequences of smoke exposure on reproductive functions. METHODS We conducted a systematic review of the scientific literature on the impact of cigarette smoking and smoke constituents on the different stages of reproductive function, including epidemiological, clinical and experimental studies. We attempted to create hypotheses and find explanations for the deleterious effects of cigarette smoke observed in experimental studies. RESULTS Cigarette smoke contains several thousand components (e.g. nicotine, polycyclic aromatic hydrocarbons and cadmium) with diverse effects. Each stage of reproductive function, folliculogenesis, steroidogenesis, embryo transport, endometrial receptivity, endometrial angiogenesis, uterine blood flow and uterine myometrium is a target for cigarette smoke components. The effects of cigarette smoke are dose-dependent and are influenced by the presence of other toxic substances and hormonal status. Individual sensitivity, dose, time and type of exposure also play a role in the impact of smoke constituents on human fertility. CONCLUSIONS All stages of reproductive functions are targets of cigarette smoke toxicants. Further studies are necessary to better understand the deleterious effects of cigarette smoke compounds on the reproductive system in order to improve health care, help to reduce cigarette smoking and provide a better knowledge of the molecular mechanisms involved in reproductive toxicology.

Evaluation of cadmium, lead, nickel and zinc status in biological samples of smokers and nonsmokers hypertensive patients

The objective of this study was to evaluate the association between trace and toxic elements zinc (Zn), cadmium (Cd), nickel (Ni) and lead (Pb) in biological samples (scalp hair, blood and urine) of smoker and nonsmoker hypertensive patients (n=457), residents of Hyderabad, Pakistan. For the purpose of comparison, the biological samples of age-matched healthy controls were selected as referents. The concentrations of trace and toxic elements were measured by atomic absorption spectrophotometer prior to microwave-assisted acid digestion. The validity and accuracy of the methodology were checked using certified reference materials and by the conventional wet acid digestion method on the same certified reference materials and real samples. The recovery of all the studied elements was found to be in the range of 97.8-99.3% in certified reference materials. The results of this study showed that the mean values of Cd, Ni and Pb were significantly higher in scalp hair, blood and urine samples of both smoker and nonsmoker patients than in referents (P<0.001), whereas the concentration of Zn was lower in the scalp hair and blood, but higher in the urine samples of hypertensive patients. The deficiency of Zn and the high exposure of toxic metals as a result of tobacco smoking may be synergistic with risk factors associated with hypertension.

Respiratory effects in people exposed to arsenic via the drinking water and tobacco smoking in southern part of Pakistan

In this study, a survey has been conducted during 2005-2007 on surface and groundwater arsenic (As) contamination and its impact on the health of local population, of villages located on the banks of Manchar lake, southern part of Sindh, Pakistan. We have also assessed the relationship between arsenic exposure through respiratory disorders in male subjects with drinking water and smoking cigarettes made from tobacco grown in agricultural land irrigated with As contaminated lake water. The biological samples (blood and scalp hair) were collected from As exposed subjects (100% smokers) and age matched healthy male subjects (40.2% smoker and 59.8% non smokers) belong to unexposed areas for comparison purposes. The As concentration in drinking water (surface and underground water), agricultural soil, cigarette tobacco and biological samples were determined by electrothermal atomic absorption spectrometry. The range of As concentrations in lake water was 35.2-158 microg/L (average 97.5 microg/L), which is 3-15 folds higher than permissible limit of World Health Organization (WHO, 2004). While the As level in local cigarette tobacco was found to be 3-6 folds higher than branded cigarettes (0.37-0.79 microg/g). Arsenic exposed subjects (with and without RD) had significantly elevated levels of As in their biological samples as compared to referent male subject of unexposed area. These respiratory effects were more pronounced in individuals who had also As induced skin lesions. The linear regressions showed good correlations between As concentrations in water versus hair and blood samples of exposed subjects with and without respiratory problems.

Determination of toxic elements in different brands of cigarette by atomic absorption spectrometry using ultrasonic assisted acid digestion

In this paper, a sample preparation method based on ultrasonic assisted acid extraction (UAE) of Al, As, Cd, Ni and Pb from filler tobacco (FT) of different local branded (LBCs) and imported branded cigarettes (IBCs) consumed in Pakistan. Acid extracts obtained upon sonication were determined by atomic absorption spectrometry. Parameters influencing extraction such as pre-sonication time 10-15 min, sonication time 2-10 min, mass of sample 0.1-0.5 g, particle size <35-125 microm and, extractant (nitric acid) concentrations (2-10%) were fully optimized to get quantitative recovery of toxic elements (TEs). The proposed method was validated with a certified reference material (CRM) Virginia tobacco leaves (ICHTJ-cta-VTL-2), and also applied a conventional acid digestion method (CDM) on same CRM, for comparative purpose. The average relative standard deviation of UAE method of CRM, ranged as 1.64-8.42% for N = 6, depending on the analytes. Extraction efficiencies for CRM were close to 97.1, 97.5, 98.5, 97.8 and 96.7 for Al, As, Cd, Ni and Pb, respectively. The concentrations of Al, As, Cd, Ni and Pb in cigarettes were present in all branded cigarettes, there is no any significance difference among LBCs and IBCs, except in few cases of LBCs, have high level of Cd and Al. Our results were compared with other worldwide studies.

Toxic metals distribution in different components of Pakistani and imported cigarettes by electrothermal atomic absorption spectrometer

It was extensively investigated that a significant flux of toxic metals, along with other toxins, reaches the lungs through smoking. In present study toxic metals (TMs) (Al, Cd, Ni and Pb) were determined in different components of Pakistani local branded and imported cigarettes, including filler tobacco (FT), filter (before and after normal smoking by a single volunteer) and ash by electrothermal atomic absorption spectrometer (ETAAS). Microwave-assisted digestion method was employed. The validity and accuracy of methodology were checked by using certified sample of Virginia tobacco leaves (ICHTJ-cta-VTL-2). The percentages (%) of TMs in different components of cigarette were calculated with respect to their total contents in FT of all branded cigarettes before smoking, while smoke concentration has been calculated by subtracting the filter and ash contents from the filler tobacco content of each branded cigarette. The highest percentage (%) of Al was observed in ash of all cigarettes, with range 97.3-99.0%, while in the case of Cd, a reverse behaviour was observed, as a range of 15.0-31.3% of total contents were left in the ash of all branded cigarettes understudy.

Blood lead and cadmium levels and relevant factors among children from an e-waste recycling town in China

BACKGROUND

Primitive electronic waste (e-waste) recycling is ongoing in Guiyu, and thus toxic heavy metals may keep on threatening to the health of local children. Some related factors may contribute to the elevation of blood lead levels (BLLs) or blood cadmium levels (BCLs).

OBJECTIVE

To investigate the children's BLLs and BCLs in Guiyu and Chendian as compare to discuss the effects of primitive e-waste recycling activities on children's health.

METHODS

Two hundred and seventy-eight children less than 8 years who lived in Guiyu and Chendian were observed, and their BLLs and BCLs were determined by graphite atomizer absorption spectrophotometer. Questionnaire survey for risk factors was also performed and data were analyzed using spearman correlation analyses and logistic regression analyses.

RESULTS

Children living in Guiyu had significantly higher BLLs and BCLs as compared with those living in Chendian (p<0.01). In Guiyu, 70.8% of children (109/154) had BLLs>10 microg/dL, and 20.1% of children (31/154) had BCLs>2 microg/L, compared with 38.7% of children (48/124) had BLLs>10 microg/dL and 7.3% of children (9/124) had BCLs>2 microg/L in Chendian (p<0.01, respectively). We also observed a significant increasing trend in BLLs with increasing age in Guiyu (p<0.01). Mean height of children in Guiyu was significantly lower than that in Chendian (p<0.01). The risk factors related to children's BLLs and BCLs mainly included father's engagement in the work related to e-waste, children's residence in Guiyu and the amount of time that children played outside near the road everyday.

CONCLUSIONS

There are close relationships between the BLLs, BCLs in children and the primitive e-waste recycling activities in Guiyu. Environmental pollution, especially lead pollution, has threatened the health of children living around e-waste recycling site.

Blood and urine levels of Pb, Cd and Hg in the general population of the Czech Republic and proposed reference values

The Human Biological Monitoring (HBM) project was launched in the Czech Republic in 1994 as a part of the nation-wide Environmental Health Monitoring System to assess the exposure of the Czech general population to a broad spectrum of environmental contaminants. Over the years 2001-2003, the concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) were determined in whole blood of 1188 adults (blood donors) and 333 children and in urine of 657 adults and 619 children. In adults, the median blood lead (B-Pb) level was 33microg/l. Men had higher B-Pb levels than women (medians 37microg/l vs. 25microg/l). Significantly higher B-Pb levels were observed in smokers compared to non-smokers (36microg/l vs. 31microg/l). In children, no sex-dependent differences were observed (median 31microg/l). In total, the median blood Cd level (B-Cd) in adults was 0.5microg/l. Smokers showed a median B-Cd level about 3 times as high as non-smokers (1.3microg/l vs. 0.40microg/l). Neither sex- nor age-related differences were observed in B-Cd levels. In 65% of children, B-Cd levels were below the limit of detection (LOD). The overall median urinary cadmium level (U-Cd) in adults was 0.31microg/g creatinine. Significantly higher U-Cd levels were found in women (median 0.39microg/g creatinine) compared to men (0.29microg/g creatinine). No significant differences were found between smokers and non-smokers. In more than 50% of children, the U-Cd level was below the LOD (=0.2microg/l). The median blood mercury (B-Hg) level in adults was 0.89microg/l. Significant differences were found between smokers (0.80microg/l) and non-smokers (0.92microg/l), and between men and women (0.86microg/l vs. 0.94microg/l). The median B-Hg level in children was 0.42microg/l and no sex-related differences were observed. The median urinary mercury (U-Hg) levels were 0.63microg/g creatinine in adults and 0.37microg/g creatinine in children. Significantly higher U-Hg levels were obtained in women and non-smokers compared to men and smokers, respectively. The B-Pb, B-Hg, U-Cd, and U-Hg levels significantly correlated with age. The following reference values were recommended for the period 2001-2003: 80, 65 and 55microg/l for B-Pb and 3.1, 4.0 and 1.5microg/l for B-Hg in men, women and children, respectively; 1.1microg/l and 1.2microg/g creatinine for B-Cd and U-Cd, respectively, in adult non-smokers; 5.4 and 12.0microg/g creatinine for U-Hg in men and women, respectively, and 3.7 and 5.5microg/g creatinine for U-Hg in boys and girls, respectively. The previous reference values for B-Pb and B-Cd needed revision and were reduced.

Cadmium, lead, and thallium in mainstream tobacco smoke particulate

The deliveries of cadmium, thallium, and lead in mainstream smoke particulate from cigarettes with different smoke delivery designs were determined by inductively coupled plasma-mass spectrometry in order to investigate their impact on the delivery of these known toxic compounds. Analyses showed that the levels of all three metals in smoke particulate were associated with their tar delivery category. After normalizing the metal concentrations to tar, there were no longer any statistically significant delivery differences between full-flavor, light or ultra-light cigarettes. When the concentrations were normalized to nicotine, the mean levels from the three delivery groups were much smaller than before normalization. But unlike the case using tar to normalize, in some of the cases, there were still some statistically significant differences in the nicotine-normalized results. These findings suggest that if smokers compensate for differences in nicotine intake, they receive exposures to toxic heavy metals from ultra-light, light and full-flavor cigarettes that are more similar than results would suggest from using the Federal Trade Commission method alone.

Effects of cadmium chloride inhalation on airflow limitation to histamine, carbachol and adenosine 5'-monophosphate assessed by barometric whole body plethysmography in healthy dogs

The effects of pharmacological bronchoprovocation on airflow patterns and surrogate respiratory parameters assessed by barometric whole body plethysmography (BWBP) were investigated in healthy dogs, previously exposed to cadmium chloride inhalation. BWBP-derived respiratory variables were calculated (1) at baseline and (2) following nebulisation of increasing concentrations of histamine, carbachol and adenosine 5'-monophosphate (AMP) until enhanced pause (PENH) increased to 300% of baseline (PCPENH300). Bronchoalveolar lavage fluid (BALF) cytology before (BCC) and after (ACC) cadmium chloride inhalation revealed cadmium-induced airway inflammation. Neutrophils increased from 6.7 +/- 7.3% (728 +/- 104/microL) BCC to 77.8 +/- 8.6% (3255 +/- 1407/microL) ACC. PCPENH300 for all three agonists significantly decreased ACC (means+/-SD) as follows: PCPENH300(histamine) 0.72 +/- 0.28 mg/mL BCC, and 0.35 +/- 0.31 mg/mL ACC (P<0.02); PCPENH300(carbachol) 0.34 +/- 0.16 mg/mL BCC, and 0.064 +/- 0.032 mg/mL ACC (P<0.02); PCPENH300(AMP) 1000 mg/mL BCC, and 415 +/- 398 mg/mL ACC (P<0.03). The only clinical sign shown was coughing. It was concluded that airway hyperresponsiveness after induced airway inflammation can be determined by BWBP in conscious small sized dogs. BWBP could be a suitable technique to study the respiratory effects of urban environmental pollution in pets.

Smoking-induced increase in urinary cadmium levels among Japanese women

OBJECTIVE

To examine if cigarette smoking will induce elevation in cadmium (Cd) in urine.

METHODS

Information on smoking habits, and urinary levels of cadmium (Cd-U), alpha(1)-microglobulin (alpha(1)-MG), beta(2)-microglobulin (beta(2)-MG), creatinine (CR or cr), and urine specific gravity (SG or sg) was cited from a combination of three previously established databases on adult Japanese women. After exclusion of those with unclear answers on smoking habits (412 cases), the combination (12,846 cases) gave 11,092, 1420 and 334 cases of never, current and former smokers, respectively, for present statistical analyses.

RESULTS

Multiple regression analyses taking Cd-U as a dependent variable and 11 regions of urine collection, age and smoking habits as independent variables showed that age and regions were powerful confounders in the analysis for the effects of smoking on Cd-U. To exclude the confounding effects, current and former smokers were paired with age- and region-matched never smoking controls in subsequent analyses. In addition, former smokers were paired with age- and region-matched current smokers. The comparison of the paired cases showed that Cd-U for current smokers was significantly higher than that for never smokers. The levels for former smokers were however not higher than the levels for never smokers. When classified by the number of cigarettes consumed per day, Cd-U for current smokers increased dependently to the number of cigarettes (about 0.09 microg/cigarette/day) with leveling off at 15 or more cigarettes. There was a subtle cigarette dose-dependent increase in alpha(1)-MG, but the increase was insignificant in case of beta(2)-MG. Estimation of the amount of Cd absorbed due to cigarette smoking followed by comparison with the increase in Cd-U suggested that almost all Cd absorbed will be excreted into urine.

CONCLUSIONS

Among currently smoking Japanese women, cadmium in urine increased in a manner dependent to the number of cigarettes consumed daily. Thus, smoking is a confounder of Cd-U evaluation even among the population with relatively high dietary Cd burden.

Determination of cadmium and lead in different cigarette brands in Jordan

Cadmium (Cd) and lead (Pb) concentrations in different cigarette brands sold and/or produced in Jordan were determined by graphite furnace atomic absorption spectrometry (GF-AAS). Average levels of Cd and Pb in different cigarette brands in Jordan were 2.64 and 2.67 microg g(-1) (DW), respectively. The results obtained in this study estimate the average quantity of Cd inhaled from smoking one packet of 20 cigarettes to be in the range of 3.65-7.30 microg. Results suggest that the quantity of Pb inhaled of smoking one packet of 20 cigarettes, is estimated to be 0.74-2.22 microg. The concentrations of Cd and Pb in cigarettes were significantly different between cigarette brands tested. Our results were compared with other worldwide studies.

Environmental tobacco smoke (ETS) exposure in children with asthma-relation between lead and cadmium, and cotinine concentrations in urine

Exposure to heavy metals from environmental tobacco smoke (ETS) was investigated in 23 children with asthma (8.4+/-3.7 yr). ETS exposure was assessed by an inquiry data-based exposure index, the urinary concentration of cotinine (U-cotinine; a major nicotine metabolite) and the house dust (fine and coarse fractions) concentrations of nicotine at home. The corresponding concentrations of the heavy metals cadmium and lead in dust and urine (U-Cd; U-Pb) were determined in the same samples. There were strong associations between the ETS exposure index and U-cotinine (r(s)=0.62; P<0.002) and nicotine in house dust (r(s)=0.77; P<0.001). There was a strong positive correlation between lead and cadmium concentrations in both fine (r(s)=0.86; P<0.001) and coarse dust (r(s)=0.57; P=0.02). Although, there was a tendency for a relation between nicotine and lead concentrations in fine dust (r(s)=0.52; P=0.06), no other significant associations were found between house dust metals and nicotine concentrations. U-Cd correlated well with U-cotinine (r(s)=0.50; P=0.02). Further, U-Pb were associated with U-cotinine, however not statistically significant (r(s)=0.41; P=0.06). A probable explanation is a direct inhalation of side-stream smoke containing heavy metals and/ or an increased pulmonary uptake, due to a small airways disease in children with asthma.

Source and health implications of high toxic metal concentrations in illicit tobacco products

A significant flux of heavy metals, among other toxins, reaches the lungs through smoking. Consequently, contaminated soil is usually avoided for tobacco cultivation. Here we compare the heavy metal concentrations in tobacco from a sample of 47 counterfeit products, representative of the substantial market for these products in the U.K., with their genuine equivalents and find significantly higher concentrations of heavy metals in the counterfeits. Trace element patterns suggest that over-application of fertilizers (phosphate and/or nitrate) is the most likely cause. Nitrogen isotopes showed no significant enrichment in 15N (delta15N range from +1.1 to +4.6% in counterfeits and from +2.5 to +3.3% in genuine tobaccos) as might be expected from a sewage or manure source of nitrate, and a mineral phosphate source is considered the more likely source of metals. Stable carbon isotopes in the same tobaccos have a wide range (delta13C -18.3 to -26.4%), indicating the influence of multiple controls during cultivation and possibly post-harvesting. A review of the health effects of heavy metal transfer from tobacco via smoke to the lungs indicates that habitual smokers of counterfeits may be risking additional harm from high levels of cadmium and possibly other metals.

Exposure assessment of male recruits in Slovenia to cadmium and lead due to biological monitoring

AIMS

In Slovenia, there were no data available for an assessment of cadmium and lead levels in the population till 2001. The present study was conducted to evaluate the cadmium and lead burden from all sources (air, food, water) with the aim of obtaining initial information on cadmium and lead levels in blood of healthy and occupationally unexposed young males.

METHODS

There were 464 participants included in the analysis of blood cadmium and lead levels, aged between 18 and 27 years, the median age being 20 years. Blood samples of maximum 2 ml were taken from the cubital vein for analysis of cadmium and lead levels.

RESULTS

There were 463 blood samples analyzed for cadmium and 464 for lead. Of all tested persons, 38.2% had less than 0.5 microg/l of cadmium in their blood and 28.2% up to 1 microg/l. The median level of blood cadmium was 0.5 microg/l. The percentage of recruits with blood lead level over 100 microg was 3.1%. The median level of blood lead was 35 microg/l. The differences in blood levels of both pollutants were statistically significant with regard to the region of permanent residence (P<0.001).

CONCLUSIONS

The results of the study give a good assessment of cadmium and lead burdening of young Slovene male population. The information obtained provides a foundation for further comparative research at the international level as well as for further study and risk assessment of individual population groups exposed to greater risk due to their lifestyle and eating habits.

Biomonitoring results and cytogenetic markers among harbour workers with potential exposure to river silt aerosols

BACKGROUND

Workers on dredgers and lighters on rivers are potentially exposed to a variety of substances.

AIMS

To determine the internal load of heavy metals and arsenic as well as levels of cytogenetic markers in workers exposed to river silt aerosols.

METHODS

One hundred exposed workers were examined up to eight times within three years. Additionally, 100 control workers were studied once. Blood samples were analysed for lead, mercury, and cadmium. Additionally, micronuclei frequency and sister chromatid exchange (SCE) rates were determined. Urinary samples were analysed for cadmium, mercury, nickel, chromium, and arsenic. Information on potential confounders, such as smoking habits and consumption of fish were assessed.

RESULTS

Apart from some increased concentrations of mercury in blood (maximum 14.6 microg/l) and arsenic in urine (maximum 356.5 microg/l) all measurements were within reference values. None of the exposure and effect markers were found to be significantly increased in exposed workers compared to non-exposed controls. In multiple linear regression models, mercury levels in blood as well as the concentration of arsenic in urine were strongly related to fish consumption. Cadmium levels in blood as well as urinary cadmium concentrations were strongly related to smoking habits. After adjusting for smoking habits, SCE rates were associated with cadmium levels in blood.

CONCLUSION

Increased exposure levels or enhanced levels of cytogenetic markers were not found in workers exposed to river silt aerosols. However, cadmium exposure in blood was related to SCE frequency.

Developmental exposure to cadmium alters responsiveness to cocaine in the rat

The purpose of the present report was to investigate the potential interactive relation between perinatal (gestation/lactation) cadmium exposure and changes in responsiveness to cocaine. In Experiment 1, adult female rats were exposed to a diet containing 50 ppm cadmium (as cadmium chloride) or a diet containing no added cadmium for 30 days prior to breeding with nonexposed males. The metal-exposure regimen continued throughout gestation, and for 15 days of lactation, at which time all animals were placed on standard rat chow diets containing no added cadmium for the remainder of the investigation. Atomic absorption assays confirmed that cadmium concentrations were significantly elevated in metal-exposed dams, littermates, and test animals. Offspring were weaned on postnatal day (PND) 21 and commenced cocaine sensitization testing on PND 70. Testing operations for controls and animals perinatally exposed to cadmium consisted of 21 daily i.p. injections of vehicle (saline) or 10 mg/kg cocaine HCl, and subsequent recording of locomotor activity. Subsequently, across successive days, all animals received 0, 10, and 20 mg/kg cocaine challenges. The results showed that cocaine sensitization was attenuated in animals perinatally exposed to cadmium. A similar pattern of antagonism was observed in Experiment 2 where a higher dose of cocaine was required to produce conditioned place preference (CPP) in cadmium-exposed animals. The implications of these findings with respect to the interactive role of cadmium in the dynamics of cocaine use/abuse remain unclear.

Prediagnostic toenail cadmium and zinc and subsequent prostate cancer risk

BACKGROUND

Cadmium is a recognized human lung carcinogen that has also been positively associated with prostate cancer mainly in occupationally exposed men. The association between dietary and supplemental zinc intake and prostate cancer has not been consistent in epidemiologic studies. We evaluated the association between prediagnostic toenail cadmium and zinc concentrations and risk of prostate cancer in a cohort in which the primary route of exposure to cadmium and zinc is the diet.

METHODS

Included in the analysis were 115 prostate cancer cases and 227 age-matched controls nested in the prospective CLUE II study located in Washington County, MD. Participants provided toenail samples at baseline in 1989. Furnace atomic absorption and flame atomic absorption were used to determine toenail cadmium and zinc concentrations, respectively. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from conditional logistic regression models.

RESULTS

Median toenail cadmium and zinc concentrations did not statistically significantly differ between prostate cancer cases (cadmium, 45.9 ppb; zinc, 155.3 ppm) and controls (cadmium, 54.5 ppb; zinc, 164.0 ppm). Prostate cancer risk did not increase with increasing concentrations of cadmium (P trend = 0.9) and did not decrease with increasing concentrations of zinc (P trend = 0.2). For both metals, the ORs for the top four fifths were each below 1.0 when compared with the bottom fifth.

CONCLUSION

Men who have high toenail cadmium concentrations in the range observed in this general population sample were not at an increased risk for prostate cancer. Although there was no evidence of a linear dose-response, these findings suggest that risk of prostate cancer may be slightly lower among men with moderate and higher zinc intake.

Heavy metals of relevance to human health induce genomic instability

Heavy metals used in medical prostheses or present in water supplies or tobacco can build up in tissues and blood and are well known to produce toxic effects. Normally, legislative controls on the levels of these substances are determined by reference to the acute toxicity data. This paper shows that cadmium and nickel can produce delayed effects in human cells in vitro, which are characteristic of genomic instability. The effects occur even at levels where no acute toxic effects can be demonstrated. Genomic instability can be demonstrated by persistent induction of cytogenetic abnormalities and delayed cell death in progeny of cells many generations after exposure. Formerly, this syndrome has only been definitively proven to occur following irradiation, but in these experiments cell populations exposed for only 1 or 24 hours were expanded over several months, involving eight passages, and the yield of chromosomal aberrations and cell loss due to lethal mutations did not decrease. The consequences of this genomic instability are not yet known but it is possible that many of the systemic symptoms associated with exposure to low concentrations of these metals could involve delayed expression of cellular damage. It is also clear that these effects cannot be predicted from acute toxicity data.

Blood levels of toxic and essential metals in motor neuron disease

Toxic and essential metals have been implicated in the pathogenesis of sporadic motor neuron disease (SMND), but attempts to measure blood levels of these metals have led to contradictory results. We, therefore, measured blood levels of various metals using paired SMND/controls. In 20 subjects with SMND (15 males, five females, mean age 56.8 years) and 20 partner controls (15 females, five males, mean age 55.0 years) cadmium, lead, mercury, copper, zinc and selenium levels were measured in blood, plasma and red cells with inductively coupled plasma mass spectrometry and manganese levels with atomic absorption spectrophotometry. Results were analysed using non-parametric tests. Hypo-osmotic red blood cellfragility was estimated in six SMND/control pairs to see if hemolysis could account for increased metal levels. The plasma cadmium level was significantly raised in SMND cases (P = 0.005), but with considerable overlap between SMND and controls. No other metal levels were significantly different, though plasma lead in SMND had a tendency to be higher than controls. No difference in red cell fragility was found between groups. In conclusion, plasma levels of cadmium were raised in this SMND group, but the biological significance of this is uncertain. The measurement of metals in the blood of SMND cases seems unwarrranted for routine diagnostic testing.