Environment and Breast Cancer: Science Review

Evidence From Humans
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Ambient air pollution is associated with the increased incidence of breast cancer in US
Wei, Y., Davis, J., Bina, W. F. Int J Environ Health Res. 2012. 22:1, 12-21.
Topic area
Environmental pollutant - Air pollution
Study design
Funding agency
Association of American Medical Colleges
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, from white women only, was included from the U.S. National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) cancer registry data on breast cancer incidence data from 1973-2007 from 9 locations: Connecticut, Hawaii, New Mexico, Utah, and the metropolitan areas of Atlanta, GA, Detroit, MI, San Francisco, CA, and Seattle, WA.
Comment about participation selection
SEER database provides information on persons diagnosed with cancer and constitutes 10% of the U.S. population. Only breast cancer incidence for white women was included in this study.
Exposures investigated
National air pollutant emissions, including CO, NOx, VOC, SO2, and PM 10, from 1940-2008 from U.S. EPA. State emission data of NOx was collected from EPA data from 1990 (NOx is generated from both industry and automobiles). Total emissions were calculated
How exposure was measured
Environmental sample Geographic location
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.
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
Linear regression of breast cancer incidence from 1973-2007 and millions of tons emitted 1953-1987:
CO r=0.82 (p<0.001)
NOX r=0.89 (p<0.001)
SO2 r=0.71 (p<0.001)
VOCs r=0.68 (p<0.001)
PM10 r=-0.24 (p=0.158)

Incidence rates in the metropolitan area were higher than in the non-metropolitan area.
Metropolitan area: 126.2 per 100,000 (95% CI 125.8-126.6)
Non-metropolitan area: 111.9 per 100,000 (95% CI 111.0-112.8)
Results Comments
The NOx emission levels increased rapidly from 1940-1976, and decreased after 1998. SEER data showed the greatest increase in breast cancer from 1986-2002.
Author address
Department of Community Medicine, Mercer University School of Medicine, Macon, Georgia, USA. wei_yd@mercer.edu