Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Reproductive and hormonal factors associated with mammographic breast density by age (United States)
El-Bastawissi, A. Y., White, E., Mandelson, M. T., Taplin, S. H. Cancer Causes & Control. 2000. 11:10, 955-63.
Topic area
Body size
Study design
Other: Population based sample analysis
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 28,984 women who obtained mammograms
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women age 20-79 years who had a screening mammogram between 6/96 and 8/97 in Seattle, Washington; women enrolled in Group Health Cooperative of Puget Sound, WA (GHC); women whose screenings were checked by radiologists Ex: prior history of breast cancer, breast augmentation, or breast reduction; missing information on breast density or important covariates
Comment about participation selection
Strengths: analyzed breast density by BMI; large population based sample; wide age range of participants; analysis by decade of life; adjusted for potential confounders Limitations: dichotomized breast density into fatty and dense breasts instead of using four categories; breast density was measured by multiple radiologists; anthropometric data self-reported; did not analyze risk of breast cancer by breast density
Exposure Investigated
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Anthropometric data self-reported
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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, BMI, parity, age at first birth, menopausal status, current HRT use, race, education, family history of breast cancer, and current OC use
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Results Comments
Inverse association between breast density and BMI, low BMI is associated with a greater breast density,(BMI < 22.4 vs >29.8), OR=7.1(6.6-7.6) trend p<0.001
Author address
Cancer Prevention Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA. aelbasta@fhcrc.org