Environment and Breast Cancer: Science Review

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
Early life exposures
Study design
Hospital based case-control
Hospital based case-control
Funding agency
NCI
NCI

Study Participants
Number of Cases
4339
4339
Number of Controls
Controls: 12760
Controls: 12760
Country where study was conducted
Multiple (USA, UK, Grece, Slovenia, Brasil, Japan,
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
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
Exposures investigated
Maternal age
Maternal age
How exposure was measured
Questionnaire, in person
Questionnaire, in person
Exposure assessment comment
Self reported maternal age, recall bias
Self reported maternal age, recall bias

Statistical Analysis
Breast cancer outcome investigated
Primary incident breast cancer
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.
No
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.
No
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
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
Strength of associations reported
Maternal age: 1.19
Maternal age: 1.19
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.
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.
