Environment and Breast Cancer: Science Review

Evidence From Humans
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Body mass index and breast cancer risk in African American women
Zhu, K., Caulfield, J., Hunter, S., Roland, C. L., Payne-Wilks, K., Texter, L. Annals of Epidemiology. 2005. 15:2, 123-8.
Topic area
Body size
Study design
Population based case-control
Study Participants
Number of Cases
304 (African American) (110 pre) (161 post)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 305
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: African American women diagnosed with breast cancer between 1995 and 1998 (cases); age 20-64 (cases); lived in Davidson, Shelby or Hamilton counties in Tennessee; had telephone service at the time of the study; controls were frequency matched to cases by a 5 year age range and by county; women without a history of breast cancer (controls) Ex: subjects with missing variables
Comment about participation selection
Strengths: analyzed the association between breast cancer and body size in African American women; stratified results by menopausal status Limitations: conducted case interviews 1 to 3 years after breast cancer diagnosis; anthropometric data were self reported; possible selection bias due to a high degree of non-participation; unable to assess the difference in BMI among participants and non-participants; used maximum height to calculate BMI which might underestimate the BMI in the elderly participants
Exposure Investigated
Exposures investigated
BMI, BMI at 18 years and annual BMI change
How exposure was measured
Questionnaire, by telephone Anthropometric measurement, 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.
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: family history of breast cancer, history of benign breast disease, alcohol use, smoking habits, menstrual status, age at menarche, menstrual cycle length, number of parities, age at first birth, miscarriages, history of
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: menopausal status
Strength of associations reported
Association between breast cancer and BMI, >30 vs. <25, OR=2.32(1.33-4.03) trend p=0.003
Association between premenopausal breast cancer and BMI, >30 vs. <25, OR=2.49(0.82-7.59) trend p=0.108
Association between postmenopausal breast cancer and BMI, >30 vs. <25, OR=2.32(1.04-5.19) trend p=0.039
Controls participation rate
Greater than 70% (72.6%)