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World J Gastroenterol. Sep 21, 2014; 20(35): 12431-12444
Published online Sep 21, 2014. doi: 10.3748/wjg.v20.i35.12431
Occupational exposures and colorectal cancers: A quantitative overview of epidemiological evidence
Enrico Oddone, Carlo Modonesi, Gemma Gatta
Enrico Oddone, Department of Public Health, Experimental and Forensic Medicine, Occupational Medicine Unit, University of Pavia, 27100 Pavia, Italy
Carlo Modonesi, Department of Biosciences, Natural History Museum, University of Parma, 43100 Parma, Italy
Gemma Gatta, Department of Preventive and Predictive Medicine, Evaluative Epidemiology Unit , Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy
Author contributions: Oddone E, Modonesi C and Gatta G contributed equally to this work; Oddone E, Modonesi C and Gatta G designed the research; Oddone E, Modonesi C and Gatta G performed the research; Oddone E, Modonesi C and Gatta G analyzed the data; Oddone E, Modonesi C and Gatta G wrote the paper.
Correspondence to: Enrico Oddone, Assistant Professor, Department of Public Health, Experimental and Forensic Medicine, Occupational Medicine Unit, University of Pavia, Via Severino Boezio 24, 27100 Pavia, Italy. enrico.oddone@unipv.it
Telephone: +39-382-592838 Fax: +39-382-593796
Received: January 27, 2014
Revised: March 21, 2014
Accepted: May 29, 2014
Published online: September 21, 2014
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.

Keywords: Colorectal cancer, Occupational exposures, Public health, Chemical compounds, Basic metals, Meta analysis

Core tip: The hypothesis that 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. This study investigated the epidemiologic relationship between colorectal cancer and exposures in several industrial activities, by means of a literature review and meta-analysis. Results pointed out increased risks of colorectal cancer for labourers exposed to chemical compounds, besides workers in the sector of machinery installation exposed to asbestos. Based on our results, the estimated crude excess risk fraction attributable to occupational exposure ranged from about 11% to about 15%.