Did TCDD exposure or service in Southeast Asia increase the risk of cancer in air force Vietnam veterans who did not spray agent orange?

Abstract

We sought to examine cancer incidence in 1482 Air Force veterans who served in Southeast Asia (SEA) and who were not occupationally exposed to herbicides. Cancer incidence between 1982 and 2003 was determined by record review and Cox proportional hazards models were used to estimate risk ratios across serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and years served in SEA categories. All sites cancer risk increased with TCDD (relative risk = 1.6, 95% confidence interval = 1.2-2.2). The risk of prostate cancer increased with years of SEA service but not with TCDD. TCDD and years of SEA service interacted with all sites cancer; the risk was greatest in those with the highest TCDD levels and the longest time served in SEA. These results suggest nonoccupational exposures to TCDD or other factors while in SEA may contribute to cancer risk in these veterans.