Environment and Breast Cancer: Science Review

Evidence From Humans
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Estrogen receptor positive breast cancers and their association with environmental factors
St-Hilaire, S., Mandal, R., Commendador, A., Mannel, S., Derryberry, D. Int J Health Geogr. 2011. 10, 32.
Topic area
Environmental pollutant
Study design
Funding agency
Idaho State University
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.
Age-adjusted average annual incidence of ER+ and ER- invasive breast cancer among Caucasian women (Hispanic and non-Hispanic) in 439 counties in 11 states from 2000-2003 NIH Surveillance, Epidemiology, and End Results (SEER) data.
Comment about participation selection
The average annual incident rates were age-adjusted to 2000 Census data
Exposure Investigated
Exposures investigated
County level population density in 2000 was a proxy for urban pollution; the proportion of the county used to grow crops in 1997 was a proxy for pesticide use; annual average county unemployment rate was a measure of socioeconomic status; 2002 national ai
How exposure was measured
GIS/geographic location Environmental samples (EPA air toxics data)
Exposure assessment comment
Breast cancer rates were collected from 2000-2003 data and exposure data ranged from 1997 to 2004.
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.
County-level: unemployment rate as a proxy for socioeconomic status; age-adjusted mortality rate for Caucasian females; meteorological parameters (average wind speed, vapor pressure, shortwave radiation, precipitation and 'heating degree days')
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
Final model included statistically significant terms for crop density and NATA cancer risk, R2 = 0.386, AICc = 2490.51

Final model included marginally significant (p < 0.10) term for crop density, R2 = 0.135, AICc = 1901.04
Results Comments
Model selection was performed to find predictors of ER+ and ER- tumors (separate models). Initial model considered environmental and demographic variables as well as county-level meteorological parameters (average wind speed, vapor pressure, shortwave radiation, precipitation and 'heating degree days') and biologically plausible' interactions. Variables with largest p-value were removed until minimized corrected AIC.
Author address
Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA. sthisoph@isu.edu
Reviewers Comments
The association between ER+ breast cancer and EPA cancer risk does not differentiate between the independent effects of the 86 toxic air pollutants.