Benzene exposure at workplace and risk of colorectal cancer in four Nordic countries

• Published in: Cancer epidemiology Vol. 55; pp. 156 - 161
• Main Authors: Talibov, Madar, Sormunen, Jorma, Hansen, Johnni, Kjaerheim, Kristina, Martinsen, Jan-Ivar, Sparen, Per, Tryggvadottir, Laufey, Weiderpass, Elisabete, Pukkala, Eero
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.08.2018; Elsevier Limited
• Subjects: Adult; Aged; Aged, 80 and over; Benzene; Benzene - adverse effects; Cancer; Case-Control Studies; Case-control study; Censuses; Cohort Studies; Colon; Colon cancer; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - epidemiology; Colorectal Neoplasms - etiology; Confidence intervals; Crude oil; Emigration; Epidemiology; Exposure; Female; Health risk assessment; Health risks; Humans; Hydrocarbons; Incidence; Ionizing radiation; Leukemia; Male; Medicin och hälsovetenskap; Middle Aged; Occupation; Occupational Diseases - epidemiology; Occupational Diseases - etiology; Occupational exposure; Occupational Exposure - adverse effects; Prognosis; Rectum; Regression analysis; Risk; Scandinavian and Nordic Countries - epidemiology; Statistical analysis; Wood; Workplace; Scandinavian and Nordic Countries; Denmark; Sweden; Norway; Iceland; Finland; Occupation; Case-control study; Benzene; Colorectal cancer
• ISSN: 1877-7821; 1877-783X; 1877-783X
• DOI: 10.1016/j.canep.2018.06.011

•Evidence on association between benzene exposure and colorectal cancer is very limited.•This study shows a link between colorectal cancer and workplace benzene exposure.•The risk of colon cancer seems to be restricted to proximal but not distal colon. The aim of this case-control study was to assess the effect of occupational benzene exposure on the risk of colorectal cancer, including its subtypes. The study included 181,709 colon cancer and 109,227 rectal cancer cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway and Sweden. Cases were identified from the Nordic Occupational Cancer Study (NOCCA) cohort. Five controls per case were selected from the same cohort, matched for country, birth year, and sex. Occupational benzene exposure for each study participant was estimated by linking their job titles to country specific job-exposure matrices. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by using conditional logistic regression models. The results were adjusted for physical strain at work, formaldehyde, ionizing radiation and wood dust. Increased risk was observed for all colorectal cancer (OR = 1.12, 95% CI 1.05–1.18) for the high decile of cumulative benzene exposure, indicating a statistically significant dose-response relationship. This excess risk was mainly seen in ascending colon (OR = 1.27, 95% CI 1.13–1.43), and transversal colon (OR = 1.21, 95% CI 1.01–1.41). The ORs in the highest exposure category were markedly higher in women than in men in all subsites of colon and rectum. This study showed an association between workplace benzene exposure and colorectal cancer. The risk was restricted to ascending and transversal colon, and was the strongest among women.