Evidence From Humans
 
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Mortality in an area contaminated by TCDD following an industrial incident
Bertazzi, P. A., Zocchetti, C., Pesatori, A. C., Guercilena, S., Sanarico, M., Radice, L. Medicina del Lavoro. 1989. 80:4, 316-29.
Topic area
Environmental pollutant - Dioxin, TCDD
Study design
Other: Cohort mortality follow up.
Funding agency
Government of the Region of Lombardy, Italian Nati
Study Participants
Number of Cases
34 breast cancer deaths
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 30,703 males and females in zones A, B, R. Female person-years: 133,755 exposed, 726,014 reference
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
People ever residing in study area between July 10, 1976, and December 31, 1984.
Exposure Investigated
Exposures investigated
Residence in zones A, B, R in or near Seveso, Italy, after contamination by 2,3,7,8 tetrachlorodibenzodioxin (TCDD) from an industrial accident July 10, 1076. Residence determined by population registry. Exposure based on residence at the date of the ac
How exposure was measured
GIS/geographic location
Exposure assessment comment
People resident elsewhere who were in accident area at time of accident and those resident in accident area, but elsewhere at the time, were not identified. The zones represent a range of exposure, combining higher and more moderate exposures. The validity of the zones as representing a gradient of exposure has been questioned.
Statistical Analysis
Breast cancer outcome investigated
Mortality from breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Age, gender
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Poisson regression
Strength of associations reported
Relative risk = 0.67 (95% CI 0.5-1.0)
Results Comments
Because dioxin is anti-estrogenic, reduced breast cancer risk was hypothesized. Authors state that changes in health record-keeping after the accident hinder comparisons of mortality before and after the accident. Mortality is an insensitive indicator for breast cancer.
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