Environment and Breast Cancer: Science Review

Evidence From Humans
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Carotenoids, alpha-tocopherols, and retinol in plasma and breast cancer risk in northern Sweden
Hulten, K., Van Kappel, A. L., Winkvist, A., Kaaks, R., Hallmans, G., Lenner, P., Riboli, E. Cancer Causes Control. 2001. 12:6, 529-37.
Study design
Nested case-control
Funding agency
Other: Swedish Council for Social Research, Swedis
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal and premenopausal separate and combined
Number in Cohort
Controls 390/ cohort: 47,194
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women participating in one of three studies: VIP (Vasterbotten Intervention Project), MONICA (Monitoring of Trends in Cardiovascular Disease), MSP (Mammary Screening Project) Ex: Lack of blood sample
Comment about participation selection
The 3 parent studies have different goals, inclusion criteria and participation rate are not mentioned, mixture of cases and controls among studies, short follow-up
Exposure Investigated
Exposures investigated
Beta-carotene, alpha-tocopherol
Exposure assessment comment
One blood sample, length of storage up to 10 years
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: Family history, race, 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
OR with 95% CI, highest versus lowest quartile of serum concentration, stratified by menopausal status, follow-up until May 1997, VIP: from 1985 (median: 1.9 years) MONICA from 1986-1990-1994 (median 2.4 years), MSP from 1995 (median < 1 month)
Strength of associations reported
All cases/controls: β carotene: 0.8 (0.5-1.4); α tocopherol: 1.3 (0.6-2.7)
Premenopausal (VIP+MONICA): β carotene: 1.6 (0.5-5.4); α tocopherol: 0.5 (0.0-6.6)
Post-menopausal (VIP+MONICA): β carotene: 0.7 (0.2-1.9); α tocopherol: 2.9 (0.7-12.4),
Post-menopausal (MSP): β carotene: 0.04 (0.1-1.2); α tocopherol: 2.3 (0.3-17.2)
Results Comments
No significant differences in plasma concentrations of beta-carotene or alpha-tocopherol were found between case and referents, however results from all 3 studies together show a 10% non-significant decrease in breast cancer risk with higher plasma level of beta-carotene.
Author address
Department of Public Health and Clinical Medicine, Umea University, Sweden. kerstin.hulten@epiph.umu.se
Reviewers Comments
Lack of clear methodology regarding use of the 3 studies, the case and control population is not the same for the combined menopausal analyses and the separate analyses.