Occupation and bladder cancer in Utah

Bladder cancer among hairdressers: a meta-analysis

Background

Occupational risks for bladder cancer in hairdressers by using hair products have been examined in many epidemiological studies. But owing to small sample sizes of the studies and the resulting lack of statistical power, the results of these studies have been inconsistent and significant associations have rarely been found.

Methods

We conducted a meta-analysis to determine summary risk ratios (SRRs) for the risk of bladder cancer among hairdressers. Studies were identified by a MEDLINE, EMBASE, CENTRAL search and by the reference lists of articles/relevant reviews. Statistical tests for publication bias and for heterogeneity as well as sensitivity analysis were applied. In addition, the study quality and the risk of bias were assessed using six criteria.

Results

42 studies were included and statistically significantly increased risks around 1.3–1.7 were found for all but one analysis. The SRR increased with duration of employment from 1.30 (95% CI 1.15 to 1.48) for ‘ever registered as hairdresser’ to 1.70 (95% CI 1.01 to 2.88) for ‘job held ≥10 years’. No difference was found between the risk for smoking-adjusted data (SRR 1.35, 95% CI 1.13 to 1.61) and no adjustment (SRR 1.33, 95% CI 1.18 to 1.50). Studies assessed as being of high quality (n=11) and of moderate quality (n=31) showed similar SRRs. There was no evidence of publication bias or heterogeneity in all analyses.

Conclusion

In summary, our results showed an increased and statistically significant risk for bladder cancer among hairdressers, in particular for hairdressers in jobs held ≥10 years. Residual confounding by smoking cannot be totally ruled out. Because of the long latency times of bladder cancer it remains an open question whether hairdressers working prior to 1980 and after 1980, when some aromatic amines were banned as hair dye ingredients, have the same risk for bladder cancer.

Case-control study of high risk occupations for bladder cancer in New Zealand

We conducted a nationwide case-control study of bladder cancer in adult New Zealanders to identify occupations that may contribute to the risk of bladder cancer in the New Zealand population. A total of 213 incident cases of bladder cancer (age 25-70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risks for bladder cancer associated with ever being employed in particular occupations and industries were calculated by unconditional logistic regression adjusting for age, sex, smoking and socio-economic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered. An elevated bladder cancer risk was observed for hairdressers (odds ratio (OR) 9.15 95% Confidence Interval (95%CI) 1.60-62.22), and sewing machinists (OR 3.07 95%CI 1.35-6.96). Significantly increased risks were not observed for several other occupations that have been reported in previous studies, including sales assistants (OR 1.03 95%CI 0.64-1.67), painters and paperhangers (OR 1.42 95%CI 0.56-3.60), sheet metal workers (OR 0.39, 95%CI 0.15-1.00), printing trades workers (OR 1.11 95%CI 0.41-3.05) and truck drivers (OR 1.36 95%CI 0.60-3.09), although the elevated odds ratios for painters, printers and truck drivers are consistent with excesses observed in other studies. Nonsignificantly increased risks were observed for tailors and dressmakers (OR 2.84 95%CI 0.62-13.05), rubber and plastics products machine operators (OR 2.82 95%CI 0.75-10.67), building workers (OR 2.15, 95%CI 0.68-6.73), and female market farmers and crop growers (OR 2.05 95%CI 0.72-5.83). In conclusion, this study has confirmed that hairdressers and sewing machinists are high risk occupations for bladder cancer in New Zealand, and has identified several other occupations and industries of high bladder cancer risk that merit further study.

Shared occupational risks for transitional cell cancer of the bladder and renal pelvis among men and women in Sweden

BACKGROUND

Unlike cancer of the bladder, cancer of the renal pelvis is not considered an occupational cancer and little is known about risks among women.

METHODS

Using the Swedish national census and cancer registry-linked data (1971-1989), we identified transitional cell cancers of the renal pelvis (N = 1,374) and bladder (N = 21,591). Correlation between cancer sites for the standardized incidence ratios (SIR) were determined using Pearson's coefficient of the log SIR. Relative risks of job exposure matrix variables were calculated using Poisson regression.

RESULTS

Both cancer sites were significantly elevated among women and men employed in the machine/electronics industry, sedentary work, and indoor work, and men in the metal industry. The highest proportion of the bladder (12%) and renal pelvis (14%) cancers occurred among men employed in shop and construction metal work. Risks by industry were more correlated among women (r = 0.49, P = 0.002) than men (r = 0.24, P = 0.04). Cancers of the renal pelvis were elevated in several occupational and industry groups for which there was no elevated bladder cancer risk.

CONCLUSION

Cancers of the renal pelvis and bladder share common occupational risk factors that may be more frequent among women. In addition, there may be some jobs that pose an increased risk specifically for cancer of the renal pelvis but not bladder.

Bladder cancer and occupation: a report from the Belgian case-control study on bladder cancer risk

BACKGROUND

The aim of this study was to add to the data on associations between occupation and bladder cancer thereby strengthening the case for focused research on specific occupational categories.

METHODS

Two hundred two cases and 390 controls participated in this population-based case-control study. Age, sex, smoking, and education adjusted odds ratios (ORs) were calculated for each occupation by unconditional logistic regression.

RESULTS

The occupational group of domestic helpers, cleaners, and launderers exhibited a significantly elevated risk of bladder cancer. Elevated non-significant risks (OR > 1.5) were observed for painters and varnishers, electronic equipment assemblers, general laborers, building finishers, carpenters and joiners, architects and engineers, and textile and garment workers.

CONCLUSIONS

This study suggests that domestic helpers, cleaners, and launderers probably experience an increased risk of bladder cancer. Although no other occupations showed significantly increased risks, the non-significantly elevated risks for painters, carpenters, and textile workers could be confirmed by results from earlier studies.

Bladder cancer incidence and exposure to polycyclic aromatic hydrocarbons among asphalt pavers

OBJECTIVES

To investigate the association between exposures to polycyclic aromatic hydrocarbons (PAH) that arises during asphalt paving, and risk of bladder cancer.

METHODS

7298 men included in the historical cohort were first employed between 1913 and 1999 in companies applying asphalt in Denmark, Norway, Finland and Israel. The minimal duration of employment for inclusion in the cohort was two seasons of work. Occupational histories were extracted from personnel files. A follow-up for cancer incidence was conducted through national cancer registries. The authors estimated exposures to benzo(a)pyrene as a marker for 4-6 ring PAH. Exposures were reconstructed by using information about changes in asphalt paving technology in each company over time, the modelled relation between production characteristics and exposure levels, and job histories. Relative risks and associated 95% confidence intervals were estimated using Poisson regression.

RESULTS

48 bladder cancers among asphalt paving workers were detected; of these, 39 cases were exposed at least 15 years before the diagnosis. Cumulative exposure to PAH was not associated with the incidence of bladder cancer. The association with average exposure became stronger when 15-year lag was considered, revealing a twofold increase in relative bladder cancer risk in the two higher exposure categories. There was an indication of exposure-response association with lagged averaged exposure. Risk estimates were adjusted for age, country, duration of employment and calendar period, did not show heterogeneity among countries and did not materially change when re-estimated after excluding non-primary cancers from follow-up. Previously conducted sensitivity analysis indicates that confounding by cigarette smoking is an unlikely explanation for the observed exposure-response trends.

CONCLUSIONS

The authors were unable to control for all possible sources of confounding and bias. The results do not allow conclusion on the presence or absence of a causal link between exposures to PAH and risk of bladder cancer among asphalt workers.

Occupational bladder cancer in New Zealand: a 1-year review of cases notified to the New Zealand Cancer Registry

AIM

To identify which cases of adult bladder cancer notified to the New Zealand Cancer Registry in 2001 had a probable occupational cause.

METHODS

Occupational Safety and Health (OSH), in conjunction with the Massey University Centre for Public Health Research, interviewed and obtained an occupational history for 210 (162 men, 48 women) cases.

RESULTS

Of the 162 male cases (response rate 65%), 45 (28%) were considered to be 'probable' occupational cancers. Of the 48 female cases (response rate 76%), three cases (6%) were considered to be 'probable' occupational cancers. The largest occupational group for men was truck drivers, which made up 51% of probable cases. Other common groups were engineering and metal workers (18%), crop farmers/orchardists (7%), textile and leather workers (7%), painters/furniture finishers (7%), and plastics manufacturing workers (4%). The three female cases considered to be of occupational origin included two textile workers and one telephonist.

CONCLUSIONS

The percentage of cases considered to be of occupational origin is similar to that reported in Europe and the United States, indicating that occupational cancer is a major occupational health problem in New Zealand as it is in other parts of the world.

Occupational risk factors for male bladder cancer: results from a population based case cohort study in the Netherlands

OBJECTIVES

This study was conducted to estimate risk of bladder cancer associated with occupational exposures to paint components, polycyclic aromatic hydrocarbons (PAHs), diesel exhausts, and aromatic amines among the general population in The Netherlands.

METHODS

A prospective cohort study was conducted among 58,279 men. In September 1986, the cohort members (55-69 years) completed a self administered questionnaire on risk factors for cancer including job history. Follow up for incident bladder cancer was established by linkage to cancer registries until December 1992. A case-cohort approach was used based on 532 cases and 1630 subcohort members. A case by case expert assessment was carried out to assign to the cases and subcohort members a cumulative probability of occupational exposure for each carcinogenic exposure.

RESULTS

Men in the highest tertiles of occupational exposure to paint components, PAHs, aromatic amines, and diesel exhaust had non-significantly higher age and smoking adjusted incident rate ratios (RRs) of bladder cancer than men with no exposure: 1.29 (95% confidence interval (95% CI) 0.71 to 2.33), 1.24 (95% CI 0.68 to 2.27), 1.32 (95% CI 0.41 to 4.23) and 1.21 (95% CI 0.78 to 1.88), respectively. The associations between paint components and PAHs and risk of bladder cancer were most pronounced for current smokers. Among former smokers it seemed that for cumulative probability of exposure to paint components and PAHs, men who had smoked more than 15 cigarettes a day had RRs below unity compared with men who had smoked less than 15 cigarettes a day, whereas among current smokers the opposite was found. Exposure to diesel exhaust was positively associated with risk of bladder cancer among current and former smokers who had smoked more than 15 cigarettes a day.

CONCLUSIONS

This study provided only marginal evidence for an association between occupational exposure to paint components, PAHs, aromatic amines, and bladder cancer. Despite the small proportion of exposed subjects, an interaction with cigarette smoking was found, specifically for paint components, suggesting that the carcinogenic effect on the bladder might decrease after stopping smoking.

A meta-analysis of bladder cancer and diesel exhaust exposure

The aim of this study is to review and summarize the available epidemiologic studies of bladder cancer and occupational exposure to diesel exhaust. We retrieved relevant studies and abstracted their characteristics and results. We assessed the heterogeneity of the results to decide whether to perform a fixed-effects model meta-analysis. We identified 35 relevant studies. No overall meta-analysis was performed because of heterogeneity in results. Results of railroad workers (N = 14) suggested an increased occurrence of bladder cancer, but we did not conduct a meta-analysis. The summary relative risk (RR) among truck drivers was 1.17 (95% confidence interval [CI] = 1.06-1.29, 15 studies) and that among bus drivers was 1.33 (95% CI = 1.22-1.45, 10 studies). Ten studies considered diesel exhaust exposure based on a job exposure matrix or a similar approach; the summary RR for these studies was 1.13 (95% CI = 1.00-1.27). A positive dose-response relation was suggested by 10 of the 12 studies that provided relevant information. The summary RR for high diesel exposure was 1.44 (95% CI = 1.18-1.76). There was some evidence of publication bias, however, with a lack of small studies with null or negative results. Our review suggests that exposure to diesel exhaust may increase the occurrence of bladder cancer, but the effects of misclassification, publication bias, and confounding cannot be fully taken into account.

Bladder cancer and occupation: a case-control study in northern Italy

OBJECTIVES

A hospital based case-control study was conducted between 1992 and 1993 in the province of Brescia, a highly industrialised area in northern Italy, to evaluate occupational risk factors of bladder cancer.

METHODS

The study evaluated 355 histologically confirmed cases of bladder cancer (275 men, 80 women) and 579 controls affected by urological non-neoplastic diseases (397 men, 182 women). Lifetime occupational history, smoking and drinking habits, and sociodemographic characteristics were recorded by means of a structured questionnaire. Odds ratios (ORs) were computed with adjustment for age, smoking, alcohol and coffee consumption, education, and place of residence.

RESULTS

A significant (P < 0.05) increase of risk of bladder cancer were found in men for labourers in the construction industry (OR 2.1, 95% confidence interval (95% CI) 1.1-3.9) and for recreational and cultural services (OR 5.0, 95% CI 1.3-18.9). Increased risks, although not significant, were found for various other occupations and industries such as machinery mechanics, metal processers and polishers, blacksmiths, gunsmiths, painters; for transport workers, an increased risk with increasing duration of employment was found.

CONCLUSIONS

Occupational exposures seem to contribute to bladder cancer risk in the area under study.

Occupation and bladder cancer: a death-certificate study

Occupational statements on death certificates of 2,457 males aged 25-64 who died from bladder cancer in selected coastal and estaurine regions of England and Wales during 1965-1980 were studied. Excess mortality was found for deck and engine room crew of ships, railway workers, electrical and electronic workers, shoemakers and repairers, and tobacco workers. An excess of cases also occurred among food workers, particularly those employed in the bread and flour confectionary industry or involved in the extraction of animal and vegetable oils and fats. Use of a job-exposure matrix revealed elevated risk for occupations in which most workers were exposed to paints and pigments, benzene and cutting oils.

Hospital records as a data source for occupational disease surveillance: a feasibility study

To assess the feasibility of using hospital records for occupational disease surveillance and to evaluate the quality of the industry/occupation (I/O) information available in these records, the computer file of all discharge diagnoses from a large health maintenance organization during 1985 was reviewed. The frequencies of discharge diagnoses previously listed as Sentinel Health Events (Occupational), or SHE (O), were calculated and three possible SHE(O) diagnoses--lung cancer, bladder cancer, and toxic hepatitis--were selected for further review. Outpatient charts of patients discharged for each diagnosis were abstracted with regard to I/O information and the discharged patients were interviewed by telephone to obtain a lifetime occupational history. The accuracy of the I/O information obtained from the hospital chart was compared to that obtained by patient interview by number of digits matched on standard classification codes. The frequencies of matches for occupation and industry were greater for "usual" than for "last" categories with both cancer diagnoses, but were similar for "usual" and "last" categories with toxic hepatitis. To assess the proportion of each possible SHE(O) diagnosis that was related to workplace exposures, the I/O information obtained by interview was rated in a blinded fashion by an experienced occupational medicine physician. The highest probability ratings for work-relatedness were noted for lung cancer, primarily due to asbestos exposure. The results of this study suggest that hospital records can be used to identify possible SHE(O); if adequate I/O information is available, then work-relatedness can be assessed. However, the accuracy of I/O obtained from hospital charts is relatively low. The efficient and accurate collection of I/O information from hospital records will require the use of a simple, easily coded instrument to be routinely administered on admission.

Bladder cancer and occupation in Shanghai, 1980-1984

To investigate occupational determinants of bladder cancer in the urban area of Shanghai, occupation and industry information for 1,219 incident bladder cancer cases diagnosed during the period 1980 to 1984 were compared with 1982 census data on employment. Standardized incidence ratios (SIR) for bladder cancer were estimated for occupation and industry classifications. Significant excess risks were observed for plastic products workers (male: SIR = 432; female: SIR = 368); textile bleachers, dyers, and finishers (male: SIR = 169); metal refining and processing workers (male: SIR = 139; female: SIR = 197); petroleum refining workers (male: SIR = 2152); railway engine drivers and firemen (male: SIR = 683); and workers employed in industries of apparel and other textile products manufacturing (female: SIR = 204); paper processing (male: SIR = 146; female: SIR = 226); organic chemical manufacturing (male: SIR = 186); plastic product manufacturing (male: SIR = 218; female: SIR = 272); and metallurgy (male: SIR = 107; female: SIR = 561). This study indicates that many of the industries and occupations that are responsible for increased risk throughout the world are also associated with occupational bladder cancer in Shanghai.

Proportion of lung and bladder cancers in males resulting from occupation: a systematic approach

Studies conducted in several countries that investigated the relationship of occupation and cancer in men were reviewed and compared. Estimates of the proportion of cancers due to occupational exposure that occurred in the general population were analyzed, and sources of variation were explored. A systematic and standardized evaluation of studies on lung and bladder cancer were undertaken, and only investigations that allowed for confounding from tobacco smoking were included. The proportion of lung cancers attributable to occupation ranged between 1 and 5% (when considering only exposure to asbestos) and 40% (in a study with a high proportion of subjects exposed to ionizing radiation); for bladder cancer, estimates were between 0 and 3% in a few studies and between 16 and 24% in several investigations. No similar attempt of systematic comparison was possible for other cancers.