Occupational cancer of the urinary bladder

Urinary bladder cancer and the petroleum industry: a quantitative review

PURPOSE

To estimate the pooled risk of petroleum industry for urinary bladder cancer.

MATERIAL AND METHODS

All observational studies that evaluated the association between urinary bladder risk and the petroleum industry were reviewed. We have only identified eight case-control studies. These studies were carried out between 1989 and 1995.

RESULTS

Of the eight localized studies six were exclusively for males. The other two studies included both males and females, but none reported separately the risk among men and women. There was an obvious risk of petroleum industry in the pooled risk (odds ratio 1.4, 95% confidence interval (CI) 1.27-1.54). Also, Q test was not significant (P>0.1), denoting homogeneity across the pooled studies. Pooled analysis applying the random effect model was 1.50 (95% CI 1.29-1.75).

CONCLUSION

Although our pooled estimate shows that the petroleum industry is associated with the risk of urinary bladder cancer, the eight studies were based on retrospective data from case-control studies. Further prospective studies evaluating the association between petroleum industry and urinary bladder cancer risk are strongly needed.

An Updated Review of the Literature: Risk Factors for Bladder Cancer with Focus on Occupational Exposures

Workplace exposures account for 5 to 25% of all bladder cancer cases. A critical review of the literature between 1938 and 2004 was performed, with a focus on occupational exposures. Occupational exposure to bladder carcinogens, particularly to beta-naphthylamine occur in a number of industries, including aromatic amine manufacture, rubber and cable manufacture, and dyestuff manufacture and use. Risks to workers in a number of new occupations and industries are reviewed. Nonoccupational risk factors that are known or at one time have been thought to increase the risk of bladder cancer are also discussed.

Estimates of work-related cancers in workers exposed to carcinogens

AIM

To evaluate the proportion of work-related cancers.

METHODS

A descriptive study of incident cases of cancer during 3 years in a French county. All people with cancer having a current or past working history were included in the studied population which was recruited from local hospitals. A working history was obtained from each subject by interview. The different organ cancers were linked using well-defined criteria, to specific occupational carcinogenic exposures. The results obtained were compared to international data on work-related cancer incidences.

RESULTS

A total of 2009 cases were included and 3.18% (64) met the criteria for work-related cancer as defined. Asbestos and polycyclic hydrocarbons were the main occupational carcinogens identified. Construction and fabricated metal products sectors were linked to almost two-thirds of work-related cancers. The percentage of the studied population with attributable risk for occupational cancer was relatively close to international data (mean 4%) and organ cancer distribution percentages did not vary significantly from international published validated data.

CONCLUSION

Work-related cancers tend to be concentrated in relatively small groups of people among whom the risk of developing the disease may be quite large. The detection of occupational hazards should therefore have a higher priority in any programme of cancer prevention. Well-defined criteria to identify specifically cancers with an occupational origin should be specified by the scientific international community.

A cohort study to estimate occupational mortality risks in Navarra

BACKGROUND

Few studies on occupational mortality have been conducted in Spain. The objective of this work was to analyse inequalities on global mortality and on mortality due to specific causes according to occupation in a historical cohort of males from the province of Navarra, Spain.

METHODS

The base population for this historical cohort comprised all employed men over age 34 from Navarra in the 1986 population register. Age-standardised point estimates and confidence intervals for occupational-specific mortality risks were computed.

RESULTS

There exist differences in mortality risks with respect to the overall risk of Navarra in certain occupational activities for several major causes of mortality. Some of the results corroborate previous findings in other works, such as the significant high risk that presents in leather, clothing workers and shoemakers when analysing kidney, bladder and other urinary malignant tumours, while others present a certain degree of novelty.

CONCLUSION

This work contributes to filling the gap in the lack of works on occupational mortality in Spain. It also complements the information that other monitoring systems may provide on occupational health.

Occupational exposure and urological cancer

Occupational exposure is definitely a major cause of cancer. In the field of urology, the urinary bladder is the most important target. A classical cause of bladder cancer is exposure to carcinogenic aromatic amines, especially benzidine and beta-naphthylamine. Such exposures were related to work places in the chemical industry, implying production and processing of classical aromatic amines, and in the rubber industry. Occupational bladder cancer has also been observed in dyers, painters and hairdressers. Even some occupations with much lower exposures to carcinogenic aromatic amines, like coke oven workers or workers in the rubber industry after the ban on beta-naphthylamine, are at risk. In these occupations, exposure to complex mixtures of substances containing combustion products (e.g. polycyclic aromatic hydrocarbons) or nitrosamines is common. Renal cell cancer has been observed as an occupational disease in cases of very high exposure to trichloroethylene having led to narcotic or prenarcotic symptoms. Occupationally related cancers of the prostate or the testes appear currently not relevant.

Mortality patterns by occupation in a cohort of electric utility workers

BACKGROUND

Mortality patterns were examined in a United States cohort of 138,905 male electric utility workers from five companies to help interpret previous studies of health effects in this industry.

METHODS

Using Poisson regression techniques, internal cohort analyses examined total mortality, cardiovascular disease, and cancer in relation to duration of employment in each of nineteen occupational categories which comprise utility operations.

RESULTS

Relative to workers who were never involved in utility operations (e.g., administrative workers), mortality rate ratios among operations workers were higher for total mortality, cardiovascular disease, and total cancer. Lung cancer risk was consistently elevated, whereas increased mortality for other cancers was less consistent.

CONCLUSIONS

The results of this study indicate excess risk of total mortality, cardiovascular disease, and some cancers among electric utility workers, which could be related to both occupational and non-occupational risk factors.

Tumors of the urinary bladder in painters: a case-control study

In a case-control study, 403 male patients with a diagnosis of "bladder tumor" and (as controls) 426 patients suffering from prostate disease were investigated. The results of this study indicate that past employment as a painter was associated with an excess risk of bladder tumor. The relative risk of bladder tumor estimated for painters was 2.76. The possible role of benzidine-based azodyes (or azodyes based on substituted benzidines) as a carcinogenic risk factor for painters is discussed.

Cancer mortality among Danish molders

This study was set up to investigate potential chronic health effects associated with molding in the foundry industry. For this purpose, a cohort of 632 male molders was followed through 10 years with regard to cause-specific mortality. Comparisons were made with another cohort of skilled workers. The mortality from cancer was increased among the molders (standardized mortality ratio 152, 95% confidence interval 100-221), mainly because of an excess number of deaths from bladder cancer (standardized mortality ratio 896, 95% confidence interval 329-1,949). It is suggested that certain mold types may emit bladder carcinogens. In addition, phenols, cresols, and aldehydes in the foundry work atmosphere might act as tumor promoters.

Occupation and bladder cancer in Utah

The relationships between bladder cancer and occupation, industries, and occupational exposures in Utah were examined in a population-based, case-control study conducted between 1977 and 1983. Life-long occupational histories were obtained for 417 cases (332 men and 85 women) and 877 controls (685 men and 192 women). Although few positive findings emerged in this study, increased risks were detected among men for employment in the leather and textile industries which increased with duration of employment. The effects were most marked for employment beginning 45 or more years prior to interview (odds ratio [OR] for textiles = 1.92, confidence interval [CI] = 0.89-4.46; for leather OR = 2.95, CI = 0.63-13.76). Among men and women, increased risk was detected among clerical workers employed for less than 10 years (OR = 1.59, CI = 1.16-2.17) although the risk decreased with increased duration of employment (OR = 0.88, CI = 0.55-1.40 for greater than or equal to 10 years). A protective effect was seen among men and women for 10 or more years employment in professional, managerial, and technical occupations (OR = 0.68, CI = 0.50-0.92). Employment as a carpenter resulted in increased risk which increased with duration. Increased risk for bladder cancer was detected among carpenters who smoked but not among carpenters who never smoked. We used an occupation-exposure linkage system to identify workers exposed to aromatic amino compounds; such workers did not have increased risk of bladder cancer, although interaction between long-term exposure to aromatic amino compounds and smoking was detected. Interactions between smoking and other industrial or occupational exposures were not demonstrated, and for the most part, smoking did not confound the estimates of the bladder cancer-occupation relationships.

Schistosome related cancers: a possible role for genotoxins

Schistosomiasis has long been associated with cancer. This association is most prevalent between Schistosoma hematobium and bladder cancer. Numerous theories have been proposed to explain the causal link between the parasite infestation and the ensuing neoplasia. One theory that has not received as much attention as others, however, is the role of genotoxins in the neoplastic process. Considering the substantial amount of supportive evidence for the cocarcinogenic effects of schistosomes, concern for the health effects resulting from exposure of infested individuals to either exogenous or endogenous genotoxins is certainly warranted.

Modified mutagen metabolism in Schistosoma hematobium-infested organisms

The relationship between parasite infestation and chemical mutagen metabolism was investigated in this study. Schistosoma hematobium, long associated with increased incidence of bladder cancer in humans, was chosen as a model parasite. Urine samples, serum samples, and liver tissue extracts (S-9) from infested and control hamsters were used with the Ames Salmonella/microsome test to follow 3,3'-dichlorobenzidine (DCB), aflatoxin B1 (AFB1), and 2-acetylaminofluorene (AAF) mutagenicity. Liver S-9 preparations from infested and control hamsters showed little difference in activation potential for DCB and AFB1. Aroclor 1254-induced rat liver S-9, however, was remarkably efficient at reducing the mutagenicity of DCB. This process was reversible by beta-glucuronidase (BG). Studies on infested and control hamsters indicated increased BG activity in serum and urine. Urine concentrates (UC) from infested and control animals were not mutagenic by themselves, but did enhance the mutagenicity of AAF and DCB in the presence of S-9 and BG. Urine concentrates from infested animals showed greater enhancement of DCB mutagenicity than did UC from control animals. These data suggest that increased BG and unknown urinary factors in infested hamsters play a role in altering chemical mutagen activity.

Cancer and polluted work places: a case-control study

The possible association between selected cancers and polluted work places has been studied in a hospital-based, case-control study. By dividing all jobs in the participants working career into "polluted" and "clean", a crude measure for the total industrial exposure a worker experiences throughout his life was established. Among 103 age-matched, case-control pairs the overall estimated relative risk (RR) for exposed subjects (greater than or equal to 10 years in a polluted work place) of developing cancer compared to nonexposed (less than 10 years in a polluted work place) was 1.1. The only subgroup where a significant difference was found between the cases and the controls was the lung cancer subgroup (RR = 4.0, p = 0.02, two-tailed). When the 30 lung cancer cases were compared to an alternative control group consisting of 60 subjects matched for age and smoking habits, an estimated RR of 4.5 was found. A moderate, but not significant association between lung cancer and definite asbestos exposure was also found (RR: 2.3). As most workers are exposed to a variety of industrial agents throughout their working careers, further development of methods for characterizing combined exposures are needed, both for retrospective and prospective purposes.