An ecological study of organochlorine pesticides and breast cancer in rural Victoria, Australia.

摘要

A number of studies have suggested that environmental contamination with organochlorine pesticides may be related to risk of breast cancer. To investigate this association in a rural part of Australia, organochlorine contamination data from a breast milk organochlorine study conducted in the state of Victoria in 1993 were used. The state was divided into 11 statistical divisions. Standardized incidence ratios (SIRs) for the 11 regions were calculated using breast cancer incidence data from 1983 to 2002. During that time, 47,250 breast cancer cases occurred in Victoria, which had an average population of 2,147,409 women. The Ovens-Murray region, which was the region most contaminated with organochlorine pesticides, showed an elevated SIR of 1.10 (95%CI, 1.03-1.17), although two other regions with lower organochlorine contamination levels also had elevated SIRs. The rural part of the Ovens-Murray region, where the main pesticide use occurred, had the highest SIR, 1.15 (95%CI, 1.07-1.23). We did not find any significant correlation between organochlorine contamination and the age-standardized rate of breast cancer across all regions. But a positive dose-response relationship using an adjusted negative binomial model was detected for heptachlor epoxide. Our study may provide limited support for the role of environmental contamination with organochlorine pesticides in the development of breast cancer.