Abstract

http://ssrn.com/abstract=943285
 
 

References (43)



 


 



Tcdd Exposure-Response Analysis and Risk Assessment


Hong Cheng


affiliation not provided to SSRN

Lesa Aylward


affiliation not provided to SSRN

Colleen Beall


affiliation not provided to SSRN

Thomas B. Starr


TBS Associates

Robert C. Brunet


University of Montreal - Department of Mathematics and Statistics


Risk Analysis, Vol. 26, Issue 4, pp. 1059-1071, August 2006

Abstract:     
We examined the relation between cancer mortality and time-dependent cumulative exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) estimated from a concentration- and age-dependent kinetic model of elimination, and we estimated incremental cancer risks at age 75. Data from the National Institute for Occupational Safety and Health study of 3,538 workers with occupational exposure to TCDD were analyzed using standardized mortality ratios and Cox regression procedures. Analyses adjusted for potential confounding by age, year of birth, and race and considered exposure lag periods of 0, 10, or 15 years. Other potential confounders including smoking and other occupational exposures were evaluated indirectly. To explore the influence of extreme values of cumulative TCDD ppt-years, we restricted the analysis to observations with exposure below the 95th percentile or used logarithmic (ln) transformed exposure values. We applied penalized smoothing splines to examine variation in the exposure-response relation across the exposure range. TCDD was not statistically significantly associated with cancer mortality using the full data set, regardless of the lag period. When we restricted the analysis to observations with exposure below the 95th percentile, TCDD was associated positively with cancer mortality, particularly when a 15-year lag was applied (untransformed exposure data: regression coefficient , standard error (s.e.) = 1.4 × 10, p < 0.05; ln-transformed exposure data: , s.e. = 2.9 × 10, p < 0.05). The estimated incremental lifetime risk of mortality at age 75 from all cancers was about 6 to more than 10 times lower than previous estimates derived from this cohort using exposure models that did not consider the age and concentration dependence of TCDD elimination.

Number of Pages in PDF File: 13

Accepted Paper Series


Date posted: November 7, 2006  

Suggested Citation

Cheng, Hong and Aylward, Lesa and Beall, Colleen and Starr, Thomas B. and Brunet, Robert C., Tcdd Exposure-Response Analysis and Risk Assessment. Risk Analysis, Vol. 26, Issue 4, pp. 1059-1071, August 2006. Available at SSRN: http://ssrn.com/abstract=943285 or http://dx.doi.org/10.1111/j.1539-6924.2006.00800.x

Contact Information

Hong Cheng (Contact Author)
affiliation not provided to SSRN
No Address Available
Lesa Aylward
affiliation not provided to SSRN
No Address Available
Colleen Beall
affiliation not provided to SSRN
No Address Available
Thomas B. Starr
TBS Associates ( email )
7500 Rainwater Road
Raleigh, NC 27615
United States
Robert C. Brunet
University of Montreal - Department of Mathematics and Statistics ( email )
Montreal, Quebec H3C 3J7
Canada
HOME PAGE: http://www.bio.net/bionet/mm/toxicol/2005-June/003588.html
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