Risk of cancer among workers exposed to trichloroethylene: analysis of three Nordic cohort studies.

BACKGROUND: Trichloroethylene (TCE) is a widely used chlorinated solvent with demonstrated carcinogenicity in animal assays. Some epidemiologic studies have reported increased risk of cancer of the kidney, cervix, liver and biliary passages, non-Hodgkin lymphoma, and esophageal adenocarcinoma. METHODS: We established a pooled cohort, including 5553 workers with individual documented exposure to TCE in Finland, Sweden, and Denmark. Study participants were monitored for the urinary TCE metabolite trichloroacetic acid from 1947 to 1989 and followed for cancer. Standardized incidence ratios (SIRs) were calculated based on cancer incidence rates in the three national populations. Cox proportionate hazard analyses were used for internal comparisons. Tests of statistical significance are two-sided. RESULTS: Overall, 997 cases of cancer (n = 683 in men; n = 314 in women) were identified during 154 778 person-years of follow-up. We observed statistically significant elevated standardized incidence ratios for primary liver cancer (1.93; 95% confidence interval [CI] = 1.19 to 2.95) and cervical cancer (2.31; 95% CI = 1.32 to 3.75). The standardized incidence ratio for kidney cancer was 1.01 (95% CI = 0.70 to 1.42) based on 32 cases; we did not observe a statistically significant increased risk of non-Hodgkin's lymphoma (SIR = 1.26; 95% CI = 0.89 to 1.73) or esophageal adenocarcinoma (SIR = 1.84; 95% CI = 0.65 to 4.65). Tobacco- and alcohol-associated cancers were not statistically significantly increased. CONCLUSIONS: Our results suggest TCE exposure is possibly associated with an increased risk for liver cancer. The relationship between TCE exposure and risks of cancers of low incidence and those with confounding by lifestyle and other factors not known in our cohort require further study.

Respiratory symptoms and lung function in foundry workers using the hot box method: a 4-year follow-up.

OBJECTIVE: To perform follow-up of lung function and respiratory and ocular symptoms in foundry workers exposed to monoisocyanates using the Hot Box method. METHODS: Four years after an initial assessment, 25 foundry workers and 55 referents completed a questionnaire and were assessed by spirometry pre- and postshift. Exposure to isocyanic acid, methyl isocyanate, and formaldehyde was measured. RESULTS: Exposure levels were reduced by 50% at follow-up. A high prevalence of nasal and ocular symptoms remained in both groups, but lower airway symptoms had decreased. Lung function preshift was lower for the exposed group, but lung function over shift was unaffected. CONCLUSIONS: The high prevalence of nasal symptoms and the small reduction of forced expiratory volume in 1 second preshift in exposed foundry workers at follow-up may indicate a prolonged influence of previous exposure in the working environment despite reduced exposure levels at follow-up.

Nasal and ocular effects in foundry workers using the hot box method.

OBJECTIVE: To investigate the prevalence of nasal and ocular symptoms and nasal signs in foundry workers exposed to monoisocyanates using the Hot Box method. METHODS: Forty-three foundry workers and 69 referents completed questionnaires and were examined by a rhinologist. Exposure to isocyanic acid, methyl isocyanate, formaldehyde, and total dust was measured. RESULTS: Nasal symptoms and signs were associated with exposure, and dose-response relationships between nasal symptoms and exposure to isocyanic acid, methyl isocyanate, and formaldehyde were observed. Dry nasal mucosa was more prevalent in exposed workers than in referents. These findings were not substantially affected by the exclusion of asthmatic and allergic individuals, smokers, or females. CONCLUSIONS: An increased prevalence of nasal symptoms and signs was observed among exposed workers, suggesting an association with the foundry environment involving monoisocyanates and other airway irritants, such as formaldehyde and dust.

Cancer morbidity in Swedish dry-cleaners and laundry workers: historically prospective cohort study.

PURPOSE: Despite decades of experimental and observational studies, the carcinogenic risks to humans associated with occupational exposure to perchloroethylene (PER) remain uncertain. The aims of the present study were to further examine the possible associations. METHODS: A national cohort of dry-cleaning and laundry workers (n = 10,389) assembled in 1984 was followed up for new cases of cancer by matching with the Swedish cancer register from 1985 to 2006 (inclusive), and the results were compared with expected frequencies derived from national reference data. RESULTS: Follow-up was complete for 90.9% of the cohort (2,810 men, 6,630 women). The overall standardised cancer incidence ratio (SIR) for all subjects was close to unity (SIR 0.96; 95% confidence interval (CI) 0.91-1.02) with a slightly more favourable outcome in women (SIR 0.91; 95% CI 0.85-0.98) than in men (SIR 1.10; 95% CI 0.99-1.23). Significantly elevated rates of lung cancer (SIR 1.45; 95% CI 1.03-1.98) and non-Hodgkin's lymphoma (SIR 2.05; 95% CI 1.30-3.07) were seen in men, but for both types of cancer, the point estimates were similar in genuine laundry workers and dry-cleaners exposed to PER, respectively. There was no significant excess of cancer of the oesophagus, larynx, uterine cervix, liver, kidney or urinary bladder. CONCLUSIONS: The absence of individual or collective data on PER exposure from participating dry-cleaning shops and laundries involved and limited information on exposure time hampered the risk assessment related to PER. However, no clear association between PER exposure and subsequent cancer morbidity in the workers was evident from this historically prospective cohort.

Respiratory symptoms and lung function in foundry workers exposed to low molecular weight isocyanates.

BACKGROUND: This study investigated the prevalence of ocular and respiratory symptoms and lung function in foundry workers exposed to isocyanic acid (ICA) and methyl isocyanate (MIC). METHODS: Foundry workers (n = 64) using the Hot Box binder technique and referents (n = 134) completed two questionnaires and a spirometry before and after a day shift. Findings were analyzed relating to exposure measurements of ICA, MIC, and formaldehyde. RESULTS: Exposed workers reported more frequently ocular irritation and coughing. Pre-shift lung function was lower than predicted in both groups of workers, and was not associated with exposure duration. Decrease in lung function over shift was more pronounced in exposed workers, but this was not associated with quantitative measures of the exposures. CONCLUSIONS: An increased prevalence of ocular and respiratory symptoms, as well as a small decrease in lung function over shift, was observed among exposed workers. No associations with exposure to monoisocyanates and formaldehyde were seen, thus suggesting that other irritants in the foundry environment might be the cause. The effects seemed to be small and not clinically relevant on an individual level. Further studies using a follow-up design may be warranted.

Nephrotoxicity of uranium in drinking water from private drilled wells.

OBJECTIVES: To investigate the association between uranium in drinking water from drilled wells and aspects of kidney function measured by sensitive urine tests. METHODS: Three hundred and one of 398 eligible subjects (75.6%) aged 18-74 years with daily drinking water supplies from private drilled wells located in uranium-rich bedrock (exposed group) volunteered to participate along with 153 of 271 local controls (56.4%) who used municipal water. Participants responded to a questionnaire on their water consumption and general health, and provided a morning urine sample and drinking water for analysis. RESULTS: The uranium content of well water samples (n=153) varied considerably (range <0.20-470 microg/l, median 6.7 microg/l, 5% >100 microg/l), while uranium levels in all samples of municipal water (n=14) were below the limit of quantification (0.2 microg/l). Urinary levels of uranium were more than eight times higher in exposed subjects than in controls (geometric means 38 and 4.3 ng/l, respectively; p<0.001), but their mean urine lead levels were not significantly different. There was a strong curvilinear correlation between uranium in drinking water and in urine (r2=0.66). Levels of albumin, beta(2)-microglobulin, protein HC as well as kappa and lambda immunoglobulin chains in urine from exposed and controls were similar. The N-acetyl-beta-d-glucosaminidase (NAG) activity was significantly lower in the exposed group vs. controls, possibly secondary to differential storage duration of samples from the two groups. Even in regression models adjusting for gender, age and smoking no association of uranium in water and the kidney function parameters was observed. Using uranium in urine in the entire study group as a marker of exposure, however, a tendency of exposure-related increases of beta(2)-microglobulin, protein HC and kappa chains were noted. This tendency was enhanced after exclusion of subjects with diabetes mellitus from the analysis. CONCLUSIONS: Uranium levels in urine were strongly correlated to levels in drinking water from drilled wells. There were no clear signs of nephrotoxicity from uranium in drinking water at levels recorded in this study, but some indications of an effect were observed using uranium in urine as a measure of overall uranium exposure. The clinical relevance of these findings remains unclear.

Polychlorinated biphenyls (PCB), thyroid hormones and cytokines in construction workers removing old elastic sealants.

OBJECTIVES: To estimate the internal PCB level in Swedish workers specialised in PCB abatement in buildings and to measure possible effects of PCB on thyroid function and aspects of the immune system. METHODS: Thirty six of 40 eligible workers (90%) removing old elastic sealants containing PCB and 33 control construction workers provided blood samples for determination of 19 PCB congeners and some other organochlorine compounds (hexachlorobenzene and p,p'-DDE), thyroid function hormones and a set of cytokines. The PCB exposed group was reinvestigated after 10 months for a trend assessment. RESULTS: The sum of 19 PCB congeners in blood plasma from the occupationally PCB-exposed group was twice the level in the controls (geometric mean 580 vs. 260 ng/g lipid; P < 0.001), and there was also some difference in p,p'-DDE between the groups while the lipid-adjusted hexachlorobenzene levels were of the same magnitude. No statistically significant increase in overall PCB levels was observed in the abatement workers at follow-up and some congeners even declined. Thyroid function was not associated with PCB exposure at the current levels and this applied also to the cytokines investigated. CONCLUSIONS: Swedish workers removing old elastic sealants with PCB have a higher internal PCB load than unexposed colleague construction workers, tentatively secondary to historical exposure. A system of protective measures seemed to be efficient since no further increase was noted after a longish period of additional exposure. There was no evidence of thyroid function or immune system involvement, as expressed by a set of cytokines, at the low PCB levels recorded.

Lead exposure from tourist earthenware: a pilot survey.

Lead from glazed earthenware used for food storage is a well-known health hazard sporadically causing lead intoxication and may be a source of disseminating lead exposure in specific population groups. To obtain a contemporary scope of the problem a pilot survey was conducted in a random sample of 2000 households with Swedish charter tourists to Greece in 2003. Response was obtained from 214 (10.7%). From these households blood samples were obtained from 33 potentially lead exposed subjects and 33 controls (participation rate among selected participants of each category was 66% and 33%, respectively). No statistically significant difference in mean blood lead was found between groups (arithmetic mean 0.13 and 0.10micromol/l for exposed and controls, respectively; p>0.05), but increased lead levels for two exposed subjects (1.0 and 0.77micromol/l) were associated with their Hellenic earthenware (tea mugs). This pilot survey, probably the first epidemiological study of the current problem, did not indicate that earthenware purchased in Greece by Swedish tourists and used for food storage is a widespread source of lead, but limitations with regard to statistical power preclude definite conclusions.

Isocyanate exposure in bathtub refinishing: à propos a case of occupational asthma.

Work-related asthma in a bathtub refinishing technician prompted measurements of isocyanate exposure in this operation. Very high levels of hexamethylene diisocyanate (HDI) oligomer, up to 8500 microg/m3 NCO, were found during top varnish spray-painting, whereas the levels of HDI monomer were substantially lower. The results suggest that only full-piece, self-contained respirators would suffice to protect technicians from serious pulmonary disease.

Cobalt release from glazed earthenware: Observations in a case of lead poisoning.

In a case of lead poisoning caused by a Greek jug, high levels of whole blood cobalt were also recorded. Cobalt was probably released from the underglaze dye by juice stored in the jug. The element was rapidly eliminated from the circulation and no signs of cardiotoxicity were observed in the patient. This case illustrates a possibly novel route of alimentary cobalt exposure.

Lead poisoning from souvenir earthenware.

A case of massive lead poisoning from juice contained in a Greek earthenware jug as well as six satellite cases of high lead exposure of similar origin is reported. The intoxicated patient was successfully treated with dimercaptosuccinic acid. Ceramic producers should adhere to the longstanding European legislation.

Occupational molybdenum exposure and a gouty electrician.

BACKGROUND: Molybdenum is an essential trace element and a component of xanthine oxidase, which catalyses the formation of urate. The toxicity of molybdenum in humans is considered to be low, but hyperuricaemia and gout-like symptoms have been observed sporadically. METHODS: A case of hyperuricaemia and gouty arthritis in a young man with occupational exposure to molybdenum is described. Improvement during an exposure-free period was followed by a relapse after a reconstruction designed to quantify his molybdenum exposure. CONCLUSION: This case seems to represent the first observation of gout associated with occupational molybdenum exposure, but the association might also be entirely circumstantial.