Environment and Breast Cancer: Science Review

Evidence From Humans
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Favorable change in mammographic parenchymal patterns and breast cancer risk factors
Salminen, T., Hakama, M., Heikkila, M., Saarenmaa, I. International Journal of Cancer. 1998. 78:4, 410-4.
Topic area
Body size
Study design
Other: Cohort analysis
Funding agency
Other: Cancer Society of Finland, Finnish Cancer I
Study Participants
Number of Cases
1260 women whose breast patterns changed to N1, P1
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 1947 (1038 pre) (221 post)
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women age 40-47 that were screened by mammography every second year and whose mammographic parenchymal pattern at initial screening was either P2 (severe involvement with prominent duct pattern occupying more than one-fourth of the volume of the breast) or DY (severe "dysplasia"); resided in Kotkla, Finland or in one of the 12 municipalities around the area
Comment about participation selection
Strengths: analyzed the association between breast cancer risk factors and the change in mammographic parenchymal patterns; high participation rate; large study Limitations: does not report how anthropometric data were obtained
Exposure Investigated
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Does not report how anthropometric data were obtained
Breast cancer outcome investigated
Other: change in mammographic parenchymal patterns
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.
Adequately controlled, confounders: age, number of pregnancies, BMI and breast size
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
BMI is associated with favorable changes in mammographic parenchymal patterns, BMI > vs <20, OR=2.3(1.8-3.0)
Breast size is associated with favorable changes in mammographic parenchymal patterns, D cup vs A cup, OR=1.5(1.2-2.0)
Author address
Tampere School of Public Health, University of Tampere, Finland. cstisa@uta.fi