Cancer incidence within a cohort occupationally exposed to asbestos: a study of dose--response relationships.
ABSTRACT The aim of our study was to analyse the dose-response relationship between occupational asbestos exposure and risk of cancer.
Our study was a retrospective morbidity study based on 2024 subjects occupationally exposed to asbestos, conducted over the period 1 January 1978 to 31 December 2004. Analysis of the dose-response relationship between occupational asbestos exposure, as a time-dependant variable, and risk of cancer was performed using a Cox model. In order to account for the effect of latency, we conducted the analysis with a lag of 10 years.
285 cases of cancers were observed in our cohort. The relative risk of pleuro-peritoneal mesothelioma, lung cancer and colorectal cancer associated with asbestos exposure, adjusted for age as a time-dependant variable and for sex, was correlated with exposure intensity (or average exposure level, AEL). The risk of cancer, whatever the anatomical site, did not increase with the duration of exposure to asbestos.
While confirming the established relationship between asbestos exposure and pleuropulmonary and peritoneal cancers, this study also suggests a causal relationship between asbestos exposure and colorectal cancer.
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ABSTRACT: Objectives: To evaluate the scientific literature concerning asbestos and lung cancer emphasizing low-level exposure. Methods: A literature search in PubMed and Embase resulted in 5,864 citations. Information from included studies was extracted using SIGN. Twenty one statements were evidence graded. Results: Histology and location are not helpful in differentiating asbestos-related lung cancer. Pleural plaques, asbestos bodies or asbestos fibers are useful as markers of asbestos exposure. The interaction between asbestos and smoking regarding lung cancer risk is between additive and multiplicative. Conclusions: The association between asbestos exposure and lung cancer risk is basically linear, but may level off at very high exposures. The relative risk for lung cancer increases between 1 and 4% per f-y/ml, corresponding to a doubling of risk at 25-100 f-y/ml. However, one high-quality case-control study showed a doubling at 4 f-y/ml.Archives of Environmental and Occupational Health 01/2014; · 0.47 Impact Factor
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ABSTRACT: A traditional belief widespread across the biomedical community was that dietary habits and genetic predisposition were the basic factors causing colorectal cancer. In more recent times, however, a growing evidence has shown that other determinants can be very important in increasing (or reducing) incidence of this malignancy. The hypothesis that environmental and occupational risk factors are associated with colorectal cancer is gaining ground, and high risks of colorectal cancer have been reported among workers in some industrial branches. The aim of this study was to investigate the epidemiologic relationship between colorectal cancer and occupational exposures to several industrial activities, by means of a scientific literature review and meta-analysis. This work pointed out increased risks of colorectal cancer for labourers occupied in industries with a wide use of chemical compounds, such as leather (RR = 1.70, 95%CI: 1.24-2.34), basic metals (RR = 1.32, 95%CI: 1.07-1.65), plastic and rubber manufacturing (RR = 1.30, 95%CI: 0.98-1.71 and RR = 1.27, 95%CI: 0.92-1.76, respectively), besides workers in the sector of repair and installation of machinery exposed to asbestos (RR = 1.40, 95%CI: 1.07-1.84). Based on our results, the estimated crude excess risk fraction attributable to occupational exposure ranged from about 11% to about 15%. However, homogeneous pattern of association between colorectal cancer and industrial branches did not emerge from this review.World journal of gastroenterology : WJG. 09/2014; 20(35):12431-12444.
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ABSTRACT: To examine mortality from digestive cancers in a Chinese miner cohort and to explore the exposure-response relationship between chrysotile mining dust and site-specific digestive cancers. A cohort of 1539 asbestos miners was followed for 26 years. Information on vital status and death causes was collected from personnel records and hospitals. Underlying causes of death from cancers were determined by combination of clinical manifestations and pathological confirmation. Individual cumulative dust exposures were estimated based on periodic dust measurements of different workshops, individuals' job title and employment duration, and treated as a time-dependent variable. Standardised mortality ratios (SMR) were calculated according to Chinese national data and stratified by exposure (levels 1-3, from low to high). Cox proportional hazard models were constructed to estimate HRs in relation to cumulative exposure with adjustment of smoking. Fifty-one deaths from digestive cancers were identified in the cohort, giving an SMR of 1.45 (95% CI 1.10 to 1.90). There was a clear exposure-response relationship between asbestos dust exposure and mortality from stomach cancer, with SMR of 2.39 (95% CI 1.02 to 5.60) and 6.49 (2.77 to 15.20) at exposure levels 2 and 3, respectively. The clear relationship remained in multivariate analysis, in which workers at the highest exposure level had HRs of 12.23 (95% CI 8.74 to 17.12). In addition, excess mortality from oesophageal and liver cancers was also observed at high exposure levels. This study provides additional evidence for the association between exposure to chrysotile mining dust and excess mortality from digestive cancers, particularly stomach cancer.Occupational and environmental medicine 01/2014; · 3.23 Impact Factor