Article Text

Download PDFPDF
Original article
Relationship between cumulative exposure to 1,2-dichloropropane and incidence risk of cholangiocarcinoma among offset printing workers
  1. Shinji Kumagai1,
  2. Tomotaka Sobue2,
  3. Takeshi Makiuchi2,
  4. Shoji Kubo3,
  5. Shinichiro Uehara4,
  6. Tomoshige Hayashi4,
  7. Kyoko Kogawa Sato4,
  8. Ginji Endo4,5
  1. 1Department of Occupational and Environmental Management, University of Occupational and Environmental Health, Kitakyusyu, Japan
  2. 2Department of Environmental Medicine and Population Sciences, Graduate School of Medicine, Osaka University, Osaka, Japan
  3. 3Department of Hepato-Biliary-Pancreatic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
  4. 4Department of Preventive Medicine and Environmental Health, Osaka City University Graduate School of Medicine, Osaka, Japan
  5. 5Ohara Memorial Institute for Science of Labor, Tokyo, Japan
  1. Correspondence to Professor Ginji Endo, Ohara Memorial Institute for Science of Labor, in Oberlin University, 1-1-12, Sendagaya, Sibuya-ku, Tokyo, Japan; endog{at}


Objectives This study aimed to evaluate the relationship between cumulative exposure to 1,2-dichloropropane (1,2-DCP) and incidence risk of cholangiocarcinoma among workers in the offset proof-printing section of a small printing company in Osaka, Japan.

Methods We identified 95 workers of a printing company (78 men and 17 women) who had been exposed to 1,2-DCP between 1987 and 2006, and calculated the standardised incidence ratio (SIR) of cholangiocarcinoma from 1987 to 2012. We estimated cumulative exposure to 1,2-DCP and calculated SIRs in four exposure categories. We also calculated incidence rate ratios (RRs) adjusted by sex, age, calendar year and dichloromethane (DCM) exposure for three exposure categories using Poisson regression analysis.

Results Cumulative exposures to 1,2-DCP ranged from 32 to 3433 ppm-years (mean, 851 ppm-years) and the SIR was 1171 (95% CI 682 to 1875). In the analysis of the four exposure categories, SIRs increased significantly in the three highest exposure categories, but not in the lowest category. Adjusted RRs in the middle and high exposure categories were 14.9 (95% CI 4.1 to 54.3) and 17.1 (95% CI 3.8 to 76.2), respectively, in the analysis without lag time, and were 11.4 (95% CI 3.3 to 39.6) and 32.4 (95% CI 6.4 to 163.9), respectively, in the analysis with a 5-year lag. The trend analysis revealed a significant increase in RR in association with increasing cumulative exposure to 1,2-DCP. DCM exposure was not significantly associated with the development of cholangiocarcinoma.

Conclusions The present study demonstrated an exposure–response relationship between exposure to 1,2-DCP and the development of cholangiocarcinoma.

  • 1,2-dichloropropane
  • Bile duct cancer
  • Printing workers

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.