Registry-based case-control studies of liver cancer and cancers of the biliary tract nested in a cohort of autoworkers exposed to metalworking fluids.
OBJECTIVE
Results are presented for a registry-based study of hepatobiliary cancer (liver and biliary tract) nested in a cohort of workers from three automobile manufacturing plants with potential exposure to metalworking fluids.


METHODS
Altogether 63 cases of hepatobiliary cancer were identified from the cohort by the Michigan cancer registries. Each case was matched to 10 controls. Odds ratios (OR) were estimated in conditional logistic regression models for lifetime exposure to straight, soluble, and synthetic metalworking fluid and fluid components.


RESULTS
Overall, hepatobiliary cancer was not associated with exposure to metalworking fluids. However, when the cases were stratified into liver cancer (N = 39) and biliary tract cancer (N = 24) the risk was nonhomogeneous across the two categories. While liver cancer was not associated with exposure to metalworking fluids, the results suggested a possible excess risk of biliary tract cancer with more than 1.0 mg/m3-years of exposure to straight metalworking fluids [OR 2.7, 95% confidence interval (95% CI) 0.9-7.6], as well as any exposure to chlorinated paraffins (OR 3.9, 95% CI 0.9-17). When exposures to straight metalworking fluids were separated into 10-year exposure periods, the odds ratio increased to 6.24 (95% CI 1.62-24.16) for exposures occurring > 20 years prior to the risk date.


CONCLUSIONS
There is limited evidence that exposure to straight metalworking fluids is associated with biliary tract cancer. The small numbers of cases of these rare cancers were reflected in the wide confidence intervals, and these findings need to be examined further in other exposed populations.
Department of Work Environment, University of Massachusetts Lowell, Lowell, MA, USA. Judy.Bardin@doh.wa.gov
Judith A
JA
Bardin
Rebecca J
RJ
Gore
David H
DH
Wegman
David
D
Kriebel
Susan R
SR
Woskie
Ellen A
EA
Eisen
D000328:Adult; D001336:Automobiles; D001661:Biliary Tract Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008824:Michigan / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure; D016017:Odds Ratio; D012042:Registries; D012307:Risk Factors