EXPOSURE-RESPONSE ANALYSIS OF CANCER MORTALITY IN A COHORT OF WORKERSEXPOSED TO ETHYLENE-OXIDE

The authors previously reported results from the largest cohort mortal ity study of ethylene oxide-exposed workers that has been conducted to date. Here they extend their previous work by quantitatively examinin g the relation between cancer mortality and ethylene oxide exposure. T his study included workers from 13 of the 14 geographically distinct f acilities that were included in the previous investigation. These faci lities began regularly using ethylene oxide to sterilize medical suppl ies or spices sometime between 1938 and 1969. Workers were followed fr om first exposure through December 31, 1987. Historical exposures to e thylene oxide were estimated using a regression model. Standard life-t able analysis was used to examine cancer mortality in three categories of cumulative exposure to ethylene oxide. The Cox proportional hazard s model was also used to examine cumulative and other measures of ethy lene oxide exposure as predictors of cancer mortality. In both the lif e-table analysis and the Cox model, a positive trend was observed in a ll lymphatic and hematopoietic cancer mortality for cumulative ethylen e oxide exposure. This trend was strengthened when ethylene oxide expo sures 10 years prior to death were discounted (lagged) and when the an alysis was restricted to neoplasms of lymphoid cell origin. Despite li mitations discussed in this paper, the authors believe that these find ings provide some support for the hypothesis that exposure to ethylene oxide increases the risk of mortality from lymphatic and hematopoieti c neoplasms. The authors intend to continue follow-up of this relative ly young cohort, which may allow more definitive conclusions to be dra wn in the future.