Occupation and bladder cancer in Pordenone (north-east Italy): a case-control study

Cigarette smoking and risk of bladder cancer: a dose-response meta-analysis

INTRODUCTION

The disease burden of bladder cancer is increasing worldwide; therefore, to deal with this situation, many studies on bladder cancer have been carried out extensively. Among these studies, the risk factors studies may provide a possible way to reduce the incidence of bladder cancer. Meta-analyses and original researches have confirmed that smoking is a risk factor of bladder cancer. However, the specific dose-response relationship between smoking and bladder cancer risk was still unclear. This meta-analysis addresses this research gap by summarizing the accumulated evidences, quantitatively.

METHODS

Relevant studies were obtained by searching PubMed, Embase and Web of Science database since inception until August 10, 2021, without restrictions. To obtain more comprehensive data, reference lists of identified articles were also browsed. Studies that reported risk estimates (relative risks (RR) or odds ratio (OR)) with 95% confidence intervals (CIs) focusing on the association between cigarette smoking and risk of bladder cancer were included in a dose-response meta-analysis.

RESULTS

A non-linear dose-response relationship was confirmed between cigarette smoking and risk of bladder cancer on the basis of 8 cohorts and 44 case-control studies. The summary relative risk of developing bladder cancer for 1 more cigarettes/day (7 cohorts and 24 case-control studies) was 1.039 (95% CI 1.038-1.040, I² = 0%), for 1 more pack-year (3 cohorts and 21 case-control studies) was 1.017(95% CI 1.016-1.019, I² = 0%) and for 1 more year of exposure (16 case-control studies) was 1.021 (95% CI 1.020-1.023, I² = 0%).

CONCLUSION

A positive non-linear dose-response relationship is confirmed between all smoking intensity, pack-years of smoking, smoking duration(years) and the risk of bladder cancer, but the plateau only occurred when smoking intensity reached 20 cigarettes/day. Further studies should report more detailed results, including those for subtypes of gender, age, region and be stratified by other risk factors to rule out residual confounding.

Residence in Proximity of a Coal-Oil-Fired Thermal Power Plant and Risk of Lung and Bladder Cancer in North-Eastern Italy. A Population-Based Study: 1995-2009

This study investigated the risk of lung and bladder cancers in people residing in proximity of a coal-oil-fired thermal power plant in an area of north-eastern Italy, covered by a population-based cancer registry. Incidence rate ratios (IRR) by sex, age, and histology were computed according to tertiles of residential exposure to benzene, nitrogen dioxide (NO2), particular matter, and sulfur dioxide (SO2) among 1076 incident cases of lung and 650 cases of bladder cancers. In men of all ages and in women under 75 years of age, no significant associations were observed. Conversely, in women aged ≥75 years significantly increased risks of lung and bladder cancers were related to high exposure to benzene (IRR for highest vs. lowest tertile: 2.00 for lung cancer and 1.94 for bladder cancer) and NO2 (IRR: 1.72 for lung cancer; and 1.94 for bladder cancer). In these women, a 1.71-fold higher risk of lung cancer was also related to a high exposure to SO2. Acknowledging the limitations of our study, in particular that we did not have information regarding cigarette smoking habits, the findings of this study indicate that air pollution exposure may have had a role with regard to the risk of lung and bladder cancers limited to women aged ≥75 years. Such increased risk warrants further analytical investigations.

Quantified relations between exposure to tobacco smoking and bladder cancer risk: a meta-analysis of 89 observational studies

BACKGROUND

Smoking is a major risk factor for bladder cancer (BC). This meta-analysis updates previous reviews on smoking characteristics and BC risk, and provides a more quantitative estimation of the dose-response relationship between smoking characteristics and BC risk.

METHODS

In total, 89 studies comprising data from 57 145 BC cases were included and summary odds ratios (SORs) were calculated. Dose-response meta-analyses modelled relationships between smoking intensity, duration, pack-years and cessation and BC risk. Sources of heterogeneity were explored and sensitivity analyses were conducted to test the robustness of findings.

RESULTS

Current smokers (SOR = 3.14, 95% CI = 2.53-3.75) and former smokers(SOR = 1.83, 95% CI = 1.52-2.14) had an increased risk of BC compared with never smokers. Age at first exposure was negatively associated with BC risk. BC risk increased gradually by smoking duration and a risk plateau at smoking 15 cigarettes a day and 50 pack-years was observed. Smoking cessation is most beneficial from 20 years before diagnosis. The population-attributable risk of BC for smokers has decreased from 50% to 43% in men and from 35% to 26% in women from Europe since estimated in 2000. Results were homogeneous between sources of heterogeneity, except for lower risk estimates found in studies of Asian populations.

CONCLUSIONS

Active smokers are at an increased risk of BC. Dose-response meta-analyses showed a BC risk plateau for smoking intensity and indicate that even after long-term smoking cessation, an elevated risk of bladder cancer remains.

Occupation and bladder cancer in a population-based case-control study in Northern New England

OBJECTIVES

We used data from a large, population-based case-control study in Maine, New Hampshire, and Vermont to examine relationships between occupation, industry and bladder cancer risk.

METHODS

Lifetime occupational histories were obtained by personal interview from 1158 patients newly diagnosed with urothelial carcinoma of the bladder in 2001-2004, and from 1402 population controls. Unconditional logistic regression was used to calculate ORs and 95% CIs, adjusted for demographic factors, smoking and employment in other high-risk occupations.

RESULTS

Male precision metalworkers and metalworking/plasticworking machine operators had significantly elevated risks and significant trends in risk with duration of employment (precision metalworkers: OR 2.2, 95% CI 1.4 to 3.4, p(trend) = 0.0065; metalworking/plasticworking machine operators: OR 1.6, 95% CI 1.01 to 2.6, p(trend) = 0.047). Other occupations/industries for which risk increased significantly with duration of employment included: for men, textile machine operators, mechanics/repairers, automobile mechanics, plumbers, computer systems analysts, information clerks, and landscape industry workers; for women, service occupations, health services, cleaning and building services, management-related occupations, electronic components manufacturing and transportation equipment manufacturing. Men reporting use of metalworking fluids (MWF) had a significantly elevated bladder cancer risk (OR 1.7, 95% CI 1.1 to 2.5).

CONCLUSIONS

Our findings support the hypothesis that some component(s) of MWF may be carcinogenic to the bladder. Our results also corroborate many other previously reported associations between bladder cancer risk and various occupations. More detailed analyses using information from the study's job-specific questionnaires may help to identify MWF components that may be carcinogenic, and other bladder carcinogens associated with a variety of occupations.

Meta-analyses of occupational exposure as a painter and lung and bladder cancer morbidity and mortality 1950-2008

The International Agency for Research on Cancer (IARC) classified occupational painting as a human carcinogen based on lung and bladder cancers; however, no specific exposures were implicated. The authors conducted comprehensive meta-analyses of the epidemiological literature on occupational painting and these cancers. The authors abstracted study results and confounder information, and used quantile plots and regression models to evaluate heterogeneity and publication bias. Summary risk estimates were derived and sensitivity analyses performed to evaluate smoking, socioeconomic status (SES), and exposure variables. Where applicable, a Bayesian approach was used to externally adjust for smoking, a major risk factor for both cancers. For lung cancer cohort mortality studies, publication bias and heterogeneity were seen, and earlier studies reported higher risk estimates than later studies. Overall lung cancer summary risk estimates were 1.29 for case-control and 1.22 and 1.36 for cohort morbidity and mortality studies, respectively, and risk estimates for bladder cancer were 1.28 for case-control and 1.14 and 1.27 for cohort morbidity and mortality studies, respectively (all statistically significant). Risks did not differ between painters and mixed occupations. Nonsignificant summary estimates resulted for lung and bladder cancers when controlling for SES, or externally adjusting for smoking in lung cancer studies. Summary risks varied by control source for case-control studies. Residual confounding by smoking and SES, lack of exposure group effect, and publication bias limit the ability of the meta-analyses to explain associations observed between occupational painting and lung and bladder cancers. Given the long latencies for lung and bladder cancers, these weak associations, if real, may not be elucidated through studies of occupational painting today.

The effect of smoking on the male excess of bladder cancer: a meta-analysis and geographical analyses

Smoking is considered the primary risk factor for bladder cancer. Although smoking prevalence and bladder cancer incidence vary around the world, bladder cancer is on average 4 times more common in males than in females. This article describes the observed male-female incidence ratio of bladder cancer for 21 world regions in 2002 and 11 geographical areas during the time period 1970-1997. A meta-analysis, including 34 studies, was performed to ascertain the increased risk for bladder cancer in males and females when smoking. The summary odds ratios (SORs) calculated in the meta-analysis were used to estimate the male-female incidence ratio of bladder cancer that would be expected for hypothetical smoking prevalence scenarios. These expected male-female incidence ratios were compared with the observed ratios to evaluate the role of smoking on the male excess of bladder cancer. The male-female incidence ratio of bladder cancer was higher than expected worldwide and over time, based on a smoking prevalence of 75% in males, 10% in females and an increased risk (SOR) of bladder cancer associated with smoking of 4.23 for males and 1.35 for females, respectively. This implied that, at least in the Western world, smoking can only partially explain the difference in bladder cancer incidence. Consequently, other factors are responsible for the difference in bladder cancer incidence.

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.

Elevated bladder cancer risk due to colorants--a statewide case-control study in North Rhine-Westphalia, Germany

Occupational exposure to aromatic amines is a known bladder cancer risk factor, whereas the impact of exposure to azo dyes, which may release aromatic amines in humans, is at present controversial. Therefore, the impact of occupational exposures to colorants was investigated in 156 bladder cancer cases and 336 controls in the state of North Rhine-Westphalia. All bladder cancer cases and controls (diagnosed with prostate cancer) requested after-care treatment. The subjects were investigated using a questionnaire for all occupations ever performed for more than 6 mo and for exposures to several possible occupational and nonoccupational bladder carcinogens. The relative bladder cancer risk was adjusted for age and smoking. The adjusted odds ratio (OR) for bladder cancer was elevated in 7 painters (OR 1.98, 95% CI 0.64-6.11), 4 hairdressers (OR 4.9, 95% CI 0.85-28.39), and 16 cases who reported a wood processing occupation (OR 1.19, 95% CI 0.58-2.41). Ten of these 16 cases reported chronic exposure to colorants (OR 1.84, 95% CI 0.68-4.95). The results of this epidemiological study confirm the hypothesis that individuals exposed to colorants show an elevated bladder cancer risk.

Bladder Cancer Risk in Painters: a Review of the Epidemiological Evidence, 1989–2004*

Epidemiological studies on the potential association between painting and the risk of bladder cancer published after the Monograph of the International Agency for Research on Cancer N. 47 of 1989 have been systematically reviewed. These included four cohort studies on the incidence of bladder cancer among painters, with a pooled relative risk (RR) of 1.10 (95% confidence interval, CI, 1.03-1.18), based on 893 cases observed. The corresponding summary RR from four cohort studies on mortality was 1.23 (95% CI 1.11-1.37), based on 370 deaths. The pooled RR from 14 case-control studies and a pooled-analysis of other 11 case-control studies was 1.35 (95% CI 1.19-1.53), based on 465 cases exposed. Overall, the RR from all epidemiological studies was 1.17 (95% 1.11-1.27). Thus, recent epidemiological evidence indicates a moderate excess risk for bladder cancer in painters. Some studies, however, suggested that any such risk would have been greater for exposures in the distant past. Open issues for interpretation include residual confounding by social class and tobacco smoking, and understanding the time-risk relation. In particular, the potential residual risk related to exposure over the last two to three decades remains to be defined.

Risk of bladder cancer in foundry workers: a meta-analysis

To clarify the inconsistent reports of bladder cancer risk in foundry workers, a meta-analytic review of epidemiological studies was undertaken. Summary risk estimates (SRE) were calculated from 40 systematically extracted results. Weakly increased risks were observed overall, with an SRE of 1.11. Twenty three selected study results with better exposure information yielded an SRE of 1.16. This weak increase in risk is consistent with estimates obtained from dose-response trends of PAH exposures in aluminium smelter workers. Summary estimates did not vary substantially with exposure quality, study design, control for smoking, or when limiting the meta-analysis to large study results. Exposure-response findings showed significantly increased risks of about 1.6 to 1.7 after 20 or more years of employment, but this was based on few studies. Occupation specific SREs showed a 40-50% increased risk among moulders, casters, and unskilled foundry labourers. There was limited evidence that bladder cancer risk correlated with lung cancer risk, which is a more established risk among foundry workers. The small increased risk observed is prone to bias and confounding. Further studies of dose-response trends would greatly aid in determining whether this observed association is causal.

Are coffee and tea consumption associated with urinary tract cancer risk? A systematic review and meta-analysis

BACKGROUND

Narrative reviews have concluded that there is a small association between coffee consumption and an increased risk of urinary tract cancer, possibly due to confounding by smoking. No association for tea consumption has been indicated. This systematic review attempts to summarize and quantify these associations both unadjusted and adjusted for age, smoking and sex.

METHOD

Thirty-four case-control and three follow-up studies were included in this systematic review. Summary odds ratios (OR) were calculated by meta-regression analyses.

RESULTS

The unadjusted summary OR indicated a small increased risk of urinary tract cancer for current coffee consumers versus non-drinkers. The adjusted summary OR were: 1.26 (95% CI : 1.09-1.46) for studies with only men, 1.08 (95% CI : 0.79-1.46) for studies with only women and 1.18 (95% CI : 1.01-1.38) for studies with men and women combined. Neither unadjusted nor adjusted summary OR provided evidence for a positive association between tea consumption and urinary tract cancer. Even though studies differed in methodology, the results were rather consistent. We did not perform dose-response analyses for coffee and tea consumption due to sparse data.

CONCLUSIONS

In accordance with earlier reviews, we found that coffee consumption increases the risk of urinary tract cancer by approximately 20%. The consumption of tea seems not to be related to an increased risk of urinary tract cancer.

Non-occupational risk factors for cancer of the lower urinary tract in Germany

In a hospital-based case-control study conducted between 1989 and 1992 in Hessen (West Germany) 300 cases (239 male and 61 female) of histologically confirmed cancer of the lower urinary tract (LUT) were individually matched to controls from the same hospitals with respect to sex, age and area of residence. Smoking of cigarettes was associated with an elevated risk of 2.80 in males (95% confidence interval (CI): 1.65-4.76) and 5.33 (95% CI: 1.55-18.33) in females, as compared with nonsmokers. Variables like daily amount of smoked cigarettes, duration of smoking, age at beginning of cigarette smoking and time since smoking cessation showed a clear dose- and time-response relationship in males, but not in females. Elevated risks were observed for higher consumption of coffee, beer and wine, but - especially for the consumption of coffee were drastically reduced after adjustment for smoking. A weak association was found between the daily fluid intake and bladder cancer in males. Among females a significantly decreased odds ratio (OR) of 0.34 (95% CI: 0.11-0.99) was found for a daily fluid intake of more than two liters. Protective effects and risk reductions of approximately 50% were found for the regular intake of raw carrots, kale, salads and fruits. The findings of this investigation support an association between lifestyle factors and cancer of the lower urinary tract.

Health and work among women in Italy: an overview of the epidemiological literature

The objective of this paper is to give an overview of the epidemiological studies completed in Italy during the past 25 years, about the role of occupational exposures on the development of adverse health effects on women. The implications for research developments are also discussed. The epidemiological investigations of selected categories of work-related health effects published in Italy in the years 1970-1995 were identified from the medical literature databases. The total number of studies is 142, including cohort mortality studies (n = 12), case-control studies of different neoplasms (n = 14), investigations of adverse reproductive effects (n = 8) and studies of occupational diseases different from the above (n = 94). In most investigations, women workers were not the main study objective and hence the number of females under study was small. The conclusions is that in Italy, given the dearth of studies of female workers and the preponderance of women in many economic sectors, i.e. the textile and shoe industry, health care, personal services and schools, there is a need to identify women workers in the above industries and occupations as priorities for epidemiological research and surveillance.

Cancer risk in the rubber industry: a review of the recent epidemiological evidence

OBJECTIVES

To examine the recent epidemiological evidence on cancer risk among workers in the rubber industry.

METHODS

Epidemiological studies published after the last detailed review by the International Agency for Research on Cancer (IARC) in 1982 were reviewed. 12 cohort studies in nine countries that examined distinct populations of workers in the rubber industry, seven industry based nested case-control studies, 48 community based case-control studies in 16 countries, and 23 studies based on administrative data that reported risks for employment in the rubber industry were identified.

RESULTS

Excess risks of bladder cancer, lung cancer, and leukaemia were found in most studies, with risks above 1.5 in about half of the studies. A moderate excess risk for laryngeal cancer was consistent across studies. Excess risks were found in a few studies for cancers of the oesophagus, stomach, colon, liver, pancreas, skin, prostate, kidney, brain, and thyroid, and for malignant lymphoma and multiple myeloma, but overall results were not consistent for these neoplasms.

CONCLUSIONS

Magnitude of the observed risks varied considerably between studies, but overall the findings indicate the presence of a widespread moderate increased cancer risk among rubber workers. The most consistent results were for bladder, laryngeal, and lung cancer and for leukaemia. Excess risks were also found for other neoplasms but an evaluation of the consistency of the findings is difficult because of the possible selective reporting of results. Recent studies do not provide information associating specific exposures with cancer risk. The preventive measures taken in the rubber industry in recent years may decrease risks, but this has not been documented yet in epidemiological studies.

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.