Risk of bile duct cancer among printing workers exposed to 1,2-dichloropropane and/or dichloromethane

• Published in: Journal of Occupational Health 2015-05, Vol.57 (3), p.230-236
• Main Authors: Sobue, Tomotaka, Utada, Mai, Makiuchi, Takeshi, Ohno, Yuko, Uehara, Shinichiro, Hayashi, Tomoshige, Sato, Kyoko Kogawa, Endo, Ginji
• Format: Article
• Language: English
• Subjects: Adult; Age of Onset; Bile duct cancer; Bile Duct Neoplasms - chemically induced; Bile Duct Neoplasms - epidemiology; Bile ducts; Cancer; Cholangiocarcinoma; Color; Dichloromethane; Ducts; Exposure; Female; Humans; Incidence; Ink; Japan - epidemiology; Male; Methylene Chloride - toxicity; Middle Aged; Occupational cohort; Occupational Diseases - chemically induced; Occupational Diseases - epidemiology; Occupational exposure; Occupational Exposure - adverse effects; Occupational health; Printing; Printing workers; Propane - analogs & derivatives; Propane - toxicity; Retrospective Studies; Risk; Risk Factors; Time Factors; Young Adult
• ISSN: 1341-9145; 1348-9585; 1348-9585
• DOI: 10.1539/joh.14-0116-OA

[Abstract]: Risk of bile duct cancer among printing workers exposed to 1,2-dichloropropane and/or dichloromethane: Tomotaka SOBUE, et al. Department of Environmental Medicine and Population Sciences, Graduate School of Medicine, Osaka University - Objectives: We conducted a retrospective cohort study to examine the risk of bile duct cancer among current and former workers in the offset color proof printing department at a printing company in Osaka, Japan. Methods: Standardized incidence ratios (SIRs) between January 1, 1985, and December 31, 2012, were estimated for the cumulative years of exposure to two chemicals, dichloromethane (DCM) and 1,2-dichloropropane (1,2-DCP), using the national incidence level as a reference. In addition, we examined risk patterns by the calendar year in which observation started. Results: Among 106 workers with a total of 1,452.4 person-years of exposure, 17 bile duct cancer cases were observed, resulting in an estimated overall SIR of 1,132.5 (95% confidence interval (CI): 659.7-1,813.2). The SIR was 1,319.9 (95%CI: 658.9-2,361.7) for those who were exposed to both DCM and 1,2-DCP, and it was 1,002.8 (95%CI: 368.0-2,182.8) for those exposed to 1,2-DCP only. SIRs tended to increase according to years of exposure to 1,2-DCP but not DCM when a 5-year lag time was assumed. The SIRs were higher for the cohorts in which observation started in 1993-2000, particularly in cohorts in which it started in 1996-1999, compared with those in which it started before or after 1993-2000. Conclusions: We observed an extraordinarily high risk of bile duct cancer among the offset color proof printing workers. Elevated risk may be related to cumulative exposure to 1,2-DCP, but there remains some possibility that a portion of the risk is due to other unidentified substances.