Environment and Breast Cancer: Science Review

Evidence From Humans
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Maternal age and birth rank of women with breast cancer
Rothman, K. J., MacMahon, B., Lin, T. M., Lowe, C. R., Mirra, A. P., Ravnihar, B., Salber, E. J., Trichopoulos, D., Yuasa, S. J Natl Cancer Inst. 1980. 65:4, 719-22.
Topic area
Early life exposures
Study design
Hospital based case-control
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Number of Controls
Controls: 12760
Country where study was conducted
Multiple (USA, UK, Grece, Slovenia, Brasil, Japan,
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: cases: All female resident in one of the seven study area (Boston, Wales, Athens, Slovenia, Sao Paulo, Tokyo, and Tapei), and who were hospitalized for a first diagnosis of breast cancer during the study period. In: controls: 3 eligible patients in beds closest to the index case, who resided in the study's areas and over 35 years of age (except when a case was <35 years of age, in which event an age match with a 2-yr range to a control was required) Ex: unreliable interviews
Comment about participation selection
Multicentric study with different breast cancer incidence and different risk factors, no report of the number of participants by area, only combined results reported
Exposure Investigated
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Self reported maternal age, recall bias
Statistical Analysis
Breast cancer outcome investigated
Primary incident breast cancer
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.
Race, BMI, alcohol consumption, 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
Standardized RR for confounders summarization score with the distribution of all controls as the standard: age. Age at first full-term delivery, social class, age at menarche, age at menopause, type of menopause, sibship size, marital status, marital hist
Results Comments
RR=1.19. P-value for trend=0.0003. A small but definite positive association found , which amounted to about 25-30% increase in breast cancer risk as maternal age increase from young to old.