Environment and Breast Cancer: Science Review

Evidence From Humans
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An ecological study of organochlorine pesticides and breast cancer in rural Victoria, Australia
Khanjani, N., English, D. R., Sim, M. R. Arch Environ Contam Toxicol. 2006. 50:3, 452-61.
Topic area
Environmental pollutant - Organochlorine pesticides DDT DDE
Study design
Funding agency
Iranian Ministry of Health and Medical Education
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses based on menopausal status
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Breast cancer incidence by age group and by four-year periods between 1983-2002 for 11 geographic regions in Victoria, Australia, obtained from population cancer registry. Female population of each region and age strata was estimated based on Australian Bureau of Statistics 1986, 1991, 1996 and 2001 censuses with interpolation for the years between censuses.
Exposure Investigated
Exposures investigated
Regional median breast milk concentrations of DDE, DDD, DDT, dieldrin, heptachlor epoxide, HCB, oxychlordane, aldrin and lindane, obtained from the Victorian Breast Milk Study in 1993.
How exposure was measured
Biological GIS/Geographic Location
Exposure assessment comment
Breastmilk samples from 787 participants were used to estimate average exposure in each of the regions. DDT was detected in 100% of samples taken between 1991 and 1993.
Breast cancer outcome investigated
Primary incident breast cancer
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, diagnosis period, and regional median family income
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Per 0.01 mg/kg increase in regional median breast milk contamination level:
Heptachlor epoxide: IRR 1.06 (95% CI 1.02-1.11)
HCB: IRR 0.96 (95% CI 0.91-1.00)
Oxychlordane: IRR 1.03 (95% CI 0.91-1.15)
DDE: IRR 1.00 (95% CI 0.99-1.00)
DDT: IRR 0.96 (95% CI 0.93-0.99)
Dieldrin: IRR 1.01 (95% CI 0.98-1.04)
Author address
Department of Epidemiology and Preventive Medicine, Monash University, The Alfred Hospital, Commercial Road, Prahran, Victoria, 3181, Australia. narges.khanjani@med.monash.edu.au
Reviewers Comments
Timing of measurement is relevant to exposure; breast milk was sampled between 1991 and 1993, just as DDT was being deregistered as a pesticide in Victoria, Australia.