Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Size at birth and risk of breast cancer: prospective population-based study
Vatten, L. J., Nilsen, T. I., Tretli, S., Trichopoulos, D., Romundstad, P. R. Int J Cancer. 2005. 114:3, 461-4.
Topic area
Early life exposures
Study design
Prospective cohort
Funding agency
Norwegian Cancer Society, Medical Research Council
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Number in Cohort
Cohort: 16,016
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Women who were alive in 1960 and born at St. Olav's hospital between 1920 and 1958 Ex: women whose mother had died before being assigned the person number, and women who were twins
Exposures investigated
Birthweight, birth length, Birth size (birthweight combined with birth length)
How exposure was measured
Other: Birth records
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.
BMI, race, parity, 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
Cox proportional hazard model adjusted for year of birth, marital status, socioeconomic status, maternal age and birth order. Adjusted RR with 95% CI, categorical variable, birthweight: >= 3840g versus < 3040g; birthlength: >=53cm versus <50 cm, combined
Strength of associations reported
Birthweight: 1.5 (1.0-2.2); birth length: 1.8 (1.2-2.6), Birthweight and birth length combined: 2.1 (1.2-3.6)
Results Comments
A modest positive association between birthweight and breast cancer, whereas for birth length there was a significant positive trend, when combined in birth size women who were in larger group at birth had a 2-fold higher risk for breast cancer in adulthood compared with women in the smaller group.
Author address
Department of Public Health and General Practice, Norwegian University of Science and Technology, Trondheim, Norway. lars.vatten@medisin.ntnu.no