MORTALITY STUDIES OF MACHINING FLUID EXPOSURE IN THE AUTOMOBILE-INDUSTRY .4. A CASE-CONTROL STUDY OF LUNG-CANCER

Machining fluids are diverse products that contain numerous additives and contaminants, including polycyclic aromatic hydrocarbons. Studies treating machining fluids as an aggregate exposure have found both pos itive and negative associations with lung cancer. In this nested case- control study of automotive workers (667 cases and 3,041 matched contr ols), individual estimates of exposure quantity and duration for speci fic classes of machining fluids were derived. An inverse dose-response relationship was found between synthetic machining fluids and lung ca ncer mortality, with an odds ratio of 0.6 (95%CI = 0.4, 0.8) for the h ighest level of lifetime exposure. The relationship was strongest for recent exposures. There was little evidence of an association with sol uble or straight oil machining fluids. Risks were inconsistently eleva ted in workers exposed to aluminum. Results from this study provide st rong evidence that exposure to machining fluids is not associated with an increased risk of lung cancer mortality in automotive workers. (C) 1997 Wiley-Liss, Inc.