Environment and Breast Cancer: Science Review

Evidence From Humans
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Parental ages at birth in relation to a daughter's risk of breast cancer among female participants in the Framingham Study (United States)
Zhang, Y., Cupples, L. A., Rosenberg, L., Colton, T., Kreger, B. E. Cancer Causes Control. 1995. 6:1, 23-9.
Topic area
Early life exposures
Study design
Prospective cohort
Funding agency
Not reported
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Number in Cohort
Cohort: 2662
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Framingham Heart Study In: Women aged 29 to 62 years at the first examination who were included in the Framingham Heart Study Ex: women who developed breast cancer prior to examination 1 or had missing information on maternal age
Comment about participation selection
Biennal follow-up for 38 years
Exposure Investigated
Exposures investigated
Maternal age, paternal age
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Self-reported parental ages: 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, 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
Cox proportional hazard model adjusted for age, education, menopausal status, parity, BMI, height, smoking and alcohol drinking and parental age. Adjusted RR with 95% CI, maternal and paternal age as categorical variable: maternal: 35+ versus <25 years, m
Strength of associations reported
Maternal age: 35+ versus <25: 1.1 (0.7-1.7), 26-31 vs <26: 1.5 (1.0 - 2.3)
paternal age: 40+ versus <30: 1.0 (0.6-1.6), 29-35 vs <29: 1.3 (0.9, 1.9)
Results Comments
Weak association between maternal age at birth and the incidence of breast cancer in daughters: the incidence increased with increasing maternal age up to the mid-30s, then levelled off, the trend was not significant. The data also suggest that there is little, if any, association between paternal age and risk of breast cancer
Author address
Department of Epidemiology and Biostatistics, School of Public Health, Boston University, MA 02118-2394, USA.