Environment and Breast Cancer: Science Review

Evidence From Humans
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Effect of body mass on the association between estrogen replacement therapy and mortality among elderly US women
Rodriguez, C., Calle, E. E., Patel, A. V., Tatham, L. M., Jacobs, E. J., Thun, M. J. American Journal of Epidemiology. 2001. 153:2, 145-52.
Topic area
Body size
Study design
Other: prospective mortality study
Funding agency
Not reported
Study Participants
Number of Cases
Breast cancer deaths: 1,541
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Number in Cohort
Cohort: 290,827
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: postmenopausal participants of the Cancer Prevention Study II Ex: women with prevalent cancer at study entry in 1982; prevalent heart disease; history of stroke; premenopausal; menopausal status or age at menopause unknown; incomplete data on estrogen use; use of estrogen in cream or injection form exclusively
Comment about participation selection
Strengths: analyzed breast cancer mortality by HRT use and BMI; controlled for many lifestyle and reproductive variables; large study with many breast cancer mortalities Limitations: exclusion criteria limited the participation rate to 43%; self-administered questionnaire; does not state how anthropometric data was obtained; estrogen users typically have healthier lifestyles which might decrease their chance of mortality due to disease; did not control for screening behaviors or stage at diagnosis; did not analyze the type of HRT used; assessment of exposures were based on a single self-administered questionnaire, which did not allow for analysis based on duration of exposure
How exposure was measured
Questionnaire, self-administered
Breast cancer outcome investigated
Mortality from breast cancer
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 at enrollment, race, marital status, education, BMI, consumption of vegetables, total fat consumption, physical activity, oc use, age at menopause, hysterectomy (yes/no), smoking status, prevalent diabetes, prevalen
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: Estrogen replacement therapy (ERT) use Follow-up: 12 years
Strength of associations reported
Association between breast cancer mortality and women who used ERT at baseline and had a BMI <22, RR=0.86(0.62-1.20) trend p=0.65
Association between breast cancer mortality and women who used ERT at baseline and had a BMI >30, RR=0.66(0.37-1.19) trend p=0.65
Author address
Department of Epidemiology and Surveillance Research, American Cancer Society, Atlanta, GA 30329-4251, USA. crodrigu@cancer.org