Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Modification of oral contraceptive relationships on breast cancer risk by selected factors among younger women
Brinton, L. A., Gammon, M. D., Malone, K. E., Schoenberg, J. B., Daling, J. R., Coates, R. J. Contraception. 1997. 55:4, 197-203.
Topic area
Body size
Study design
Population based case-control
Funding agency
Not reported
Study Participants
Number of Cases
1,647 (1302 white) (256 african-american) (89 other)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Number of Controls
Control: 1,501 (1180 white) (217 african american) (104 other)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women less than 45 years of age; diagnosed with breast cancer between 5/1/90 and 12/31/92; lived in one of five counties in New Jersey, in Atlanta, Georgia or in Seattle/Puget Sound, Washington Ex: women without residential telephones; women with a previous hisory of breast cancer
Comment about participation selection
Strengths: large breast cancer study with many cases; administered in-person interviews; analyzed breast cancer risk by duration of oc use, age and BMI; noted the race of the participants; one of the few studies to analyze oc use by duration Limitations: did not specify whether anthropometric measurements were taken by trained staff; did not have information on types of benign breast disease
Exposure Investigated
How exposure was measured
Questionnaire, in person Other: Anthropometric measurement, unspecified
Exposure assessment comment
Does not specify how anthropometric data was obtained
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Non-hispanic White 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.
Adequately controlled, Confounders: age, study site, duration of oc use, race, parity, age at first birth, age at menarche, previous breast biopsy, BMI, fam history of bc, alcohol consumption
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
Effect modifiers: duration of oc use and age
Strength of associations reported
Association between breast cancer and women under 45 years of age with a low BMI, <22 vs. >28.8, RR=1.55(1.2-1.9)
Association between breast cancer and women under 45 years of age with a low BMI, <22 vs. >28.8, who used oral contraceptives for 5 years or more, RR=1.51 trend p=0.05
Association between breast cancer and women under 35 years of age with a low BMI, <22 vs. >28.8, who used oral contraceptives for 5 years or more, RR=2.51 trend p=0.02
Results Comments
No outstanding results or association between breast cancer risk among OC use and BMI
Author address
Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892, USA. brinton@epndce.nci.nih.gov
Controls participation rate
Greater than 70% (78.7%)