Environment and Breast Cancer: Science Review

Dual effects of weight and weight gain on breast cancer risk. [see comment]
Huang, Z., Hankinson, S. E., Colditz, G. A., Stampfer, M. J., Hunter, D. J., Manson, J. E., Hennekens, C. H., Rosner, B., Speizer, F. E., Willett, W. C. JAMA. 1997. 278:17, 1407-11.

Topic area
Body size
Body size
Study design
Prospective cohort
Prospective cohort
Funding agency
NCI
NCI

Study Participants
Number of Cases
2,517 (1,000 premenopausal) (1,517 postmenopausal) (invasive only)
2,517 (1,000 premenopausal) (1,517 postmenopausal) (invasive only)
Menopausal Status
Post menopausal
The menopausal status of women included in this study is listed here.
Pre menopausalPost menopausal
Number in Cohort
Cohort: 95,256
Cohort: 95,256
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women in the Nurses' Health Study I Cohort: age 30 to 55 years at baseline in 1976, lived in 1 of 11 US states, and was a registered nurse
Ex: Women with a previous cancer other than nonmelanoma skin cancer, women with incomplete information on risk factors, women who self-reported breast cancer whose records failed to confirm this diagnosis and women diagnosed with in situ breast cancer
Comment about participation selection
Strengths: Large cohort study that covered 1,203,498 person years of follow up, lengthy follow-up of 16 years, examines BMI in relation to breast cancer risk among women classified by use of postmenopausal hormones, separated BMI exposure into 10 groups, sent follow up questionnaire every two years for sixteen years, high participation rate and analyzed a subsample of 184 participants to measure the accuracy of self-reported weights Limitations: Anthropometric data self-reported
Strengths: Large cohort study that covered 1,203,498 person years of follow up, lengthy follow-up of 16 years, examines BMI in relation to breast cancer risk among women classified by use of postmenopausal hormones, separated BMI exposure into 10 groups, sent follow up questionnaire every two years for sixteen years, high participation rate and analyzed a subsample of 184 participants to measure the accuracy of self-reported weights Limitations: Anthropometric data self-reported
Exposures investigated
BMI and weight change from 18 years to the beginning of each follow up interval
BMI and weight change from 18 years to the beginning of each follow up interval
How exposure was measured
Questionnaire, self-administered
Questionnaire, self-administered
Exposure assessment comment
Anthropometric data self-reported
Anthropometric data self-reported
Breast cancer outcome investigated
Primary breast cancer
Primary breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
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, height, family history of breast cancer, history of benign breast disease, age at menarche, parity, age at first birth and HRT 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.
No
Description of major analysis
Effect modifiers: menopausal status Interaction: weight gain by HRT use Follow up: 16 years (1976-1992)
Effect modifiers: menopausal status Interaction: weight gain by HRT use Follow up: 16 years (1976-1992)
Strength of associations reported
Association between premenopausal breast cancer risk and BMI, >31.0 vs. <20.0 kg, OR=0.62(0.45-0.86) trend p<0.001
Association between postmenopausal breast cancer risk and BMI, >31.0 vs. <20.0 kg, OR=1.13(0.87-1.46) trend p=0.53
Association between premenopausal breast cancer risk and weight change, >25.0 kg gain vs. 2 kg loss or gain, OR=0.74(0.54-1.03) trend p=0.07
Association between postmenopausal breast cancer risk and weight change, >25.0 kg gain vs. 2 kg loss or gain, OR=1.41(1.12-1.78) trend p=0.006
Association between premenopausal breast cancer risk and BMI, >31.0 vs. <20.0 kg, OR=0.62(0.45-0.86) trend p<0.001
Association between postmenopausal breast cancer risk and BMI, >31.0 vs. <20.0 kg, OR=1.13(0.87-1.46) trend p=0.53
Association between premenopausal breast cancer risk and weight change, >25.0 kg gain vs. 2 kg loss or gain, OR=0.74(0.54-1.03) trend p=0.07
Association between postmenopausal breast cancer risk and weight change, >25.0 kg gain vs. 2 kg loss or gain, OR=1.41(1.12-1.78) trend p=0.006

Author address
Department of Nutrition, Harvard School of Public Health, Boston, MA, USA.
Department of Nutrition, Harvard School of Public Health, Boston, MA, USA.