Environment and Breast Cancer: Science Review

Evidence From Humans
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A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer
Wolk, A., Bergstrom, R., Hunter, D., Willett, W., Ljung, H., Holmberg, L., Bergkvist, L., Bruce, A., Adami, H. O. Arch Intern Med. 1998. 158:1, 41-5.
Study design
Prospective cohort
Funding agency
Other: Swedish Cancer Society, Uppsala and Vastman
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Pre menopausal
Number in Cohort
Cohort 61,471
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women aged 40 through 76 years living in the 2 counties selected for the Swedish Mammography Screening Cohort (SMSC)
Comment about participation selection
Breast cancer screening for every participant
Exposure Investigated
Exposures investigated
Fat; saturated, monounsaturated, polyunsaturated
How exposure was measured
Questionnaire, self-administered, FFQ
Exposure assessment comment
65 food items FFQ
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 considered: Race
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
Adjusted RR with 95% CI, mutually adjusted for subtypes of fat, highest versus lowest quartile of intake and intake in continuous form by unit of increment (10g/d for monounsaturated and 5 g/d for polyunsaturated). Stratification of monounsaturated by pol
Strength of associations reported
Total fat: 1.00 (0.76-1.32): saturated fat: 1.20 (0.89-1.63), monounsaturated fat: 0.80 (0.52-1.21); polyunsaturated fat: 1.18 (0.85-1.64)
Results Comments
No positive association between intake of total fat and risk of invasive breast cancer. However, monounsaturated fat and polyunsaturated fat had independent opposite effect: monounsaturated fat was significantly inversely and polyunsaturated fat significantly positively associated with risk of invasive breast cancer.
Author address
Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden.