Environment and Breast Cancer: Science Review

Evidence From Humans
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Can obesity explain the racial difference in stage of breast cancer at diagnosis between black and white women?
Cui, Y., Whiteman, M. K., Langenberg, P., Sexton, M., Tkaczuk, K. H., Flaws, J. A., Bush, T. L. Journal of Womens Health & Gender-Based Medicine. 2002. 11:6, 527-36.
Topic area
Body size
Study design
Retrospective cohort
Funding agency
Other: US Department of Defense and the Women's He
Study Participants
Number of Cases
450 breast cancers diagnosed > stage II (195 black) (255 white)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 966 (381 black) (585 White)
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 with medical records from on of two hospitals in Baltimore metropolitan area; age 20-85 years; diagnosed with primary breast cancer between 1/91 and 12/97 Ex: breast cancers previously diagnosed and treated at another hospital; diagnosed at least 2 months before study period; women with a previous malignancy; self-reported race other than white or black; women whose charts were unavailable
Comment about participation selection
Strengths: analyzed breast cancer characteristics and stage of diagnosis by race; 40% of the cohort were african americans; looked at the affect of BMI on the stage of breast cancer diagnosis among black vs white women; findings on the effect of obesity on stage of diagnosis by race were comparable to other studies; large study with many breast cancer patients Limitations: anthropometric data self-reported; retrospective study; did not obtain information on menopausal status;
Exposure Investigated
Exposure assessment comment
Anthropometric data were self-reported
Breast cancer outcome investigated
Breast cancer recurrence or progression
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
African Americans Non-hispanic White 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 and BMI
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
Association between obese women and later stage of breast cancer diagnosis (TNM Stage II or greater), BMI >30 vs <25, OR=1.54(1.10-2.16)
Results Comments
Obesity was positively associated with later stage of breast cancer at diagnosis for women of both races. Obesity explained approximately 30% of the observed racial difference in stage of breast cancer at diagnosis, although this was primarily seen in young women.
Author address
Department of Epidemiology and Preventive Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201, USA.