Environment and Breast Cancer: Science Review

Evidence From Humans
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Prospective study of carotenoids, tocopherols, and retinoid concentrations and the risk of breast cancer
Sato, R., Helzlsouer, K. J., Alberg, A. J., Hoffman, S. C., Norkus, E. P., Comstock, G. W. Cancer Epidemiol Biomarkers Prev. 2002. 11:5, 451-7.
Study design
Nested case-control
Funding agency
Study Participants
Number of Cases
346 (244 from 1974 and 115 from 1989)
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal and premenopausal combined
Number in Cohort
Controls: 346 (244 from 1974 and 115 from 1989)/ cohort of 23,850 in 1974, 25080 in 1989
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Female residents of Washington County, Maryland, who participated in a blood collection campaign in 1974, 1989 or both years Ex:Diagnosed with invasive cancer with exception of nonmelanoma skin cancer and in situ cancer of the cervix before breast cancer for cases or before selection for controls
Comment about participation selection
Two cohorts in the same county 15 years apart with 64 matched set of women participating in both cohorts
Exposure Investigated
Exposures investigated
Beta-carotene; alpha-tocopherol
Exposure assessment comment
One blood sample, stockage 5 or 20 years
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: BMI, family history, alcohol consumption, parity
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 OR with 95%CI, highest versus lowest quintile of intake, analysis by cohort, stratification by year of diagnosis for the 1974 cohort, menopausal status, and estrogen receptors; subgroup excluding vitamin supplement users, follow-up 20 years for t
Strength of associations reported
1974 cohort: β carotene: 0.41 (0.22-0.79); α tocopherol: 0.94 (0.52-1.73)
1989 cohort:; β carotene: 0.62 (0.27-1.42); α tocopherol: 0.67 (0.28-1.2)
Results Comments
Beta-carotene was significantly associated with reduced risk of breast cancer in the 1974 cohort, but in the 1989 the evidence of a protection was weak; results stratified by menopausal status or tumor estrogen receptor did not differ from the unstratified analyses.
Author address
Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.