Silica and asbestos exposure at work and the risk of bladder cancer in Canadian men: a population-based case-control study

Abstract

Background: Silica and asbestos are recognized lung carcinogens. However, their role in carcinogenesis at other organs is less clear. Clearance of inhaled silica particles and asbestos fibers from the lungs may lead to translocation to sites such as the bladder where they may initiate carcinogenesis. We used data from a Canadian populationbased case-control study to evaluate the associations between these workplace exposures and bladder cancer. Methods: Data from a population-based case-control study were used to characterize associations between workplace exposure to silica and asbestos and bladder cancer among men. Bladder cancer cases (N = 658) and age-frequency matched controls (N = 1360) were recruited within the National Enhanced Cancer Surveillance System from eight Canadian provinces . Exposure concentration, frequency and reliability for silica and asbestos were assigned to each job, based on lifetime occupational histories, using a combination of job-exposure profiles and expert review. Exposure was modeled as ever/never, highest attained concentration, duration (years), highest attained frequency (% worktime) and cumulative exposure. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated using adjusted logistic regression. Results: A modest (approximately 20%) increase in bladder cancer risk was found for ever having been exposed to silica, highest attained concentration and frequency of exposure but this increase was not statistically significant. Relative to unexposed, the odds of bladder cancer were 1.41 (95%CI: 1.01-1.98) times higher among men exposed to silica at work for ≥27 years. For asbestos, relative to unexposed, an increased risk of bladder cancer was observed for those first exposed ≥20 years ago (OR:2.04, 95%CI:1.25-3.34), those with a frequency of exposure of 5-30% of worktime (OR:1.45, 95%CI:1.06-1.98), and for those with < 10 years of exposure at low concentrations (OR:1.75, 95%CI:1.10-2.77) and the lower tertile of cumulative exposure (OR:1.69, 95%CI:1.07-2.65). However, no clear exposure-response relationships emerged. Conclusions: Our results indicate a slight increase in risk of bladder cancer with exposure to silica and asbestos, suggesting that the effects of these agents are broader than currently recognized. The findings from this study inform evidence-based action to enhance cancer prevention efforts, particularly for workers in industries with regular exposure.

Occupational characterization of workers exposed to asbestos: an integrative review

“…Outras neoplasias decorrentes da exposição ao asbesto são bucais, de faringe, de esôfago, de fígado e de ducto biliar, sendo a mortalidade por essas causas verificada em trabalhadores manuais da indústria de asbesto, seguidos dos setores automobilístico, naval e construção civil 21,22 . Essa circunstância comprova o potencial cancerígeno das fibras 51,52 .…”

Androgen receptor modulation and bladder cancer prevention – a short review

“…Majority of the studies are cohort ones, but there are also case-control studies carried out all over the world. The research has focused primarily on assessing the risk of developing BCa [31][32][33][34][35][36], but also overall survival rates [37], overall incidence [38], mortality odds ratio [32,39,40] and lifetime prevalence [41,42]. Most of the studies have found an increased risk of developing BCa among exposed workers.…”

“…Moreover, numerous cases of BCa are observed among workers working in the dying process. This is because of Different types of work silica, asbestos Canada [33] Painters and rubber manufacturing industry painting, trichloroethylene, asbestos, wood dust, diesel gasoline exhausts, formaldehyde, and painting or varnish)…”

Scoping Review of 5 Common Occupational Cancers and Their Related Exposures

“…Figure 2 shows the geographical distribution of studies worldwide. Eight studies were conducted in France (21)(22)(23)(24)(25)(26)(27)(28) and Canada (29)(30)(31)(32)(33)(34)(35)(36). There were also 4 papers in Germany (37)(38)(39)(40), and 3 in Finland (41)(42)(43).…”

“…The effect of diesel motor exhausts (DME) was investigated in 5 studies (27,33,37,40,47). Silica and/or asbestos (31,49) polycyclic aromatic hydrocarbons (PAH), and/or aromatic amines (39,65) were examined in 2 studies. Furthermore, 2 studies examined metalworking fluids (MWFs) (23,51).…”