Environment and Breast Cancer: Science Review

Evidence From Humans
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A meta-analysis of studies of dietary fat and breast cancer risk
Boyd, N. F., Martin, L. J., Noffel, M., Lockwood, G. A., Trichler, D. L. Br J Cancer. 1993. 68:3, 627-36.
Study design
Meta-analysis of cohort studies
Funding agency
Other: Canadian Ministry of health, Medical Resear
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Postmenopausal and premenopausal combined
Number in Cohort
Cohort 252,765
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Studies containing a specific estimate of breast cancer risk associated with intake of fat or fat containing foods. Ex: Studies which did not contain food groups determined as meat, milk, and cheese.
Comment about participation selection
Heterogeneity between studies
Exposure Investigated
Exposures investigated
Fat: total, saturated, monounsaturated, polyunsaturated
Exposure assessment comment
Not all studies have validated their questionnaire
Statistical Analysis
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.
Not available
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
RR that had the most confounders in the analysis including at least adjustment for energy intake and risk factors for breast cancer; summary RR with 95% CI (RR are estimates of the mean of the statistical distribution and average effect for each study); h
Strength of associations reported
Total fat: 1.03 (0.92-1.16); saturated fat: 0.95 (0.84-1.08); monounsaturated fat 0.95 (0.84-1.08); polyunsaturated fat: 1 (0.89-1.13)
Results Comments
This quantitative summary of the published literature on the risk of breast cancer associated with dietary fat intake suggests that intake of dietary fat is not associated with breast cancer.
Author address
Division of Epidemiology and Statistics, Ontario Cancer Institute, Toronto, Canada.