| Title | Quantitative Cancer Risk Assessment based on NIOSH and UCC Epidemiological Data for Workers Exposed to Ethylene Oxide. | | Author(s) | Valdez-Flores C, Sielken Jr RL, Teta MJ | | Institution | Sielken & Associates Consulting Inc. 3833 Texas Avenue, Suite 230, Bryan, TX 77802. | | Source | Regul Toxicol Pharmacol 2009 Oct 16. | | Abstract | The most recent epidemiological data on individual workers in the NIOSH and updated UCC occupational studies have been used to characterize the potential excess cancer risks of environmental exposure to ethylene oxide (EO). In addition to refined analyses of the separate cohorts, power has been increased by analyzing the combined cohorts. In previous SMR analyses of the separate studies and the present analyses of the updated and pooled studies of over 19,000 workers, none of the SMRs for any combination of the 12 cancer endpoints and 6 sub-cohorts analyzed were statistically significantly greater than one including the ones of greatest previous interest: leukemia, lymphohematopoietic tissue, lymphoid tumors, NHL, and breast cancer. In our study, no evidence of a positive cumulative exposure-response relationship was found. Fitted Cox proportional hazards models with cumulative EO exposure do not have statistically significant positive slopes. The lack of increasing trends was corroborated by categorical analyses. Cox model estimates of the concentrations corresponding to a 1-in-a-million extra environmental cancer risk are all greater than approximately 1 ppb and are more than 1,500-fold greater than the 0.4 ppt estimate in the 2006 EPA draft IRIS risk assessment. The reasons for this difference are identified and discussed. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19840826 |
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