Environment and Breast Cancer: Science Review

Evidence From Humans
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An ecological study of the association of environmental chemicals on breast cancer incidence in Texas
Coyle, Y. M., Hynan, L. S., Euhus, D. M., Minhajuddin, A. T. Breast Cancer Res Treat. 2005. 92:2, 107-14.
Topic area
Environmental pollutant - Organic solvents, styrene
Study design
Other: Ecologic epidemiology
Funding agency
Natalie Ornish Fund, Clay Weed Memorial Trust Fund
Study Participants
Number of Cases
54,487 invasive breast cancer cases (including 577 males); 254 counties
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Invasive breast cancer in Texas counties 1995-2000 vs. 2000 standard US population
Exposure Investigated
Exposures investigated
Toxics Release Inventory (TRI) 1988-2000 for 12 toxicants: carbon tetrachloride, formaldehyde, methylene chloride, styrene, tetrachloroethylene, trichloroethylene, arsenic, cadmium, chromium, cobalt, copper, nickel based on (1) associated with breast ca
How exposure was measured
GIS/geographic location Environmental sample
Exposure assessment comment
Ecologic assessment. Assessment based on address at diagnosis may not reflect the etiologic period and provides no information about duration of exposure. Limited to large emitters required to report to TRI.
Breast cancer outcome investigated
Primary breast cancer, age-adjusted county average annual breast cancer rate for men and women together and separately 1995-2000.
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Hispanic Americans African Americans
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.
Race and ethnicity. It would be helpful to know whether TRI releases in Texas counties are highly correlated with urbanicity, county income, county education, and reproductive patterns in order to evaluate whether variation in TRI releases can be differe
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
Analyses included: Mann-Whitney U test to compare median average annual age-adjusted breast cancer rates for women and men combined in counties reporting any TRI release vs. not. Multiple linear regression.
For 10 of the 12 toxicants, TRI releases were associated with higher breast cancer incidence (p < 0.04). In multiple regression, styrene was significantly associated with county breast cancer rate for women and men (R-squared 9%), women (R-squared 10%), and women > 50 (R-squared 14%). Regression models did not yield good fit for separate ethnic groups.
Results Comments
Texas ranks first among states in TRI-reported styrene releases. 61 counties had styrene releases. Styrene was previously used in the synthetic rubber industry and now also in plastics manufacturing, resins, coatings, and paints. Exposure also comes from tobacco smoke, food, building materials, consumer products, rug backings
Author address
Department of Internal Medicine, Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9103, USA. yvonne.coyle@utsouthwestern.edu