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.

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.

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.

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.

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.

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.