Environment and Breast Cancer: Science Review

Evidence From Humans
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Weight gain, body mass index, hormone replacement therapy, and postmenopausal breast cancer in a large prospective study. [see comment]
Feigelson, H. S., Jonas, C. R., Teras, L. R., Thun, M. J., Calle, E. E. Cancer Epidemiology, Biomarkers & Prevention. 2004. 13:2, 220-4.
Topic area
Body size -
Study design
Prospective cohort
Funding agency
ACS (self-funded)
Study Participants
Number of Cases
1,934 cases (1,182 non-HRT users) (752 HRT users)
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Number in Cohort
Cohort: 62,756
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: Participants of the ACS: Cancer Prevention Study (CPS)-II Nutrition Cohort; age at baseline (1992) 50-74 Ex: Women lost to follow up (baseline to 8/1999), prevalent breast or other cancer at baseline, unspecified menopausal status, pre or perimenopausal women, women with extreme values of Ht, BMI, or Weight, women with unknown height or weight, women with net weight loss of >5 lbs since 18 yrs of age, women with reported HRT use but unsure of type, women with invalid HRT use responses.
Comment about participation selection
Strengths: large prospective design so that HRT users and non users can be examined separately with adequate statistical power. Limitations: reliance on self reported height and weight at only two periods during life, 98% of participants were white
Exposure Investigated
Exposures investigated
BMI in 1992, weight gain from age 18
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Self administered questionnaire regarding body size
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 menarche, age at menopause, number of live births, age at first live birth, oral contraceptive use, family history of breast cancer, personal history of breast cysts, screening mammography, height, education, rec
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 modifers: HRT use; Interactions:exposure with all confounders Follow up:9 yrs
Strength of associations reported
Association between breast cancer risk and BMI in non-HRT users, >35.0 vs. <22.0, RR=1.08(0.75-1.55) trend p=0.11
Association between breast cancer risk and BMI in current HRT users, >35.0 vs. <22.0, RR=0.73(0.45-1.21) trend p=0.002
Association between breast cancer risk and adult weight gain from age 18 to the year 1992 in non-HRT users, >71 lbs vs. <5 lbs, RR=2.13(1.50-3.01) trend p<0.0001
Association between breast cancer risk and adult weight gain from age 18 to the year 1992 in current HRT users, >71 lbs vs. <5 lbs, RR=1.13(0.72-1.76) trend p=0.53
Author address
Department of Epidemiology and Surveillance Research, American Cancer Society, Atlanta Georgia 30329, USA. heather.feigelson@cancer.org