Meta-Analysis of Dioxin Cancer Dose-Response for Three Occupational Cohorts
Kenny S. Crump, Richard Canady, Manolis Kogevinas
Environmental Health Perspectives (to appear)
Abstract
This paper presents a meta analysis of data from three cohorts occupationally exposed to TCDD and related compounds. A statistically significant (p = 0.02) trend was found in total cancer mortality with increasing dioxin exposure. The trend tests show an increase in total cancer at cumulative TEQ serum levels that would result from lifetime intake of 7 pg TEQ/kg body wt/day, with no increase at 6 pg/kg/day. A linear dose response provided a good fit to the combined data, and predicted an ED01 (dioxin exposure resulting in a 0.01 increase in lifetime risk of cancer mortality) of 45 pg/kg/day (95% CI: 21, 324). USEPA estimates that current lifetime human exposures to dioxin average approximately 1 pg/kg/day (99% percentile 3 pg/kg/day). Although it appears unlikely that current exposures through foods would reach either 7 pg/kg/day or the ED01, our analysis argues for careful consideration of the upper ranges of long-term average exposures for dioxins.
KEY WORDS: dioxin, dose-response assessment, meta-analysis, carcinogen, occupational cohort
