Seveso women's health study: does zone of residence predict individual TCDD exposure?

The compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is produced as an unwanted by-product of various chemical reactions and combustion processes , including the manufacture of chlorinated phenols and derivatives. In anim als, TCDD exposure is associated with toxic, carcinogenic, developmental, a nd reproductive effects. In 1976, a chemical plant explosion in Seveso, Italy, exposed the residents in the surrounding community to the highest exposure to TCDD known in huma ns. Materials from an aerosol cloud of sodium hydroxide, sodium trichloroph enate and TCDD were deposited over an 18.1 km(2) area. As evidence of the s ignificant level of TCDD exposure, numerous animals died and 193 cases of c hloracne were reported among residents of the area. Initially, the contamin ated area was divided into three major exposure Zones (A, B, R) based on th e concentration of TCDD in surface soils. To date, the majority of epidemiologic studies conducted in Seveso have use d Zone of residence as a proxy measure of exposure. The purpose of the pres ent study is to validate the use of Zone of residence in Seveso as a proxy measure of exposure against individual serum TCDD measurement, and to deter mine whether questionnaire information can improve the accuracy of the expo sure classification. Using data collected from the Seveso Women's Health St udy (SWHS), the first comprehensive epidemiologic study of the reproductive health of women in Seveso, we determined that Zone of residence is a good predictor of individual serum TCDD level, explaining 24% of the variance. U sing questionnaire information could have improved prediction of individual exposure levels in Seveso, increasing the percent of the variation in seru m TCDD levels explained to 42%. (C) 2001 Elsevier Science Ltd. All rights r eserved.