Environment and Breast Cancer: Science Review

Evidence From Humans
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Serum vitamin A and subsequent risk of cancer: cancer incidence follow-up of the Finnish Mobile Clinic Health Examination Survey
Knekt, P., Aromaa, A., Maatela, J., Aaran, R. K., Nikkari, T., Hakama, M., Hakulinen, T., Peto, R., Teppo, L. Am J Epidemiol. 1990. 132:5, 857-70.
Study design
Nested case-control
Funding agency
Other: Cancer Society of Finland
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal and premenopausal combined
Number in Cohort
Controls: 123 women / cohort:36265 men and women
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women 15-99 years initially free from cancer, participating in the Finnish Social Insurance Institution’s Mobile Clinic Health Survey Ex: Women lacking data on vitamins
Comment about participation selection
Longitudinal study, limited baseline characteristics
Exposure Investigated
Exposure assessment comment
All cases and controls had a low intake of beta-carotene, serum beta-carotene level depends strongly on recent intake of the corresponding nutrient and a single serum sample may not be sufficient to reflect nutritional status. Storage length of serum sample: 11-15 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: Menopausal status, alcohol, family history of breast cancer
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, mean follow-up of 8 years, stratified for smoking as an effect modifier on beta-carotene serum level, latency of 2 years
Results Comments
Positive protective association between serum beta-carotene level and future risk of breast cancer
Author address
Social Insurance Institution, Helsinki, Finland.