Environment and Breast Cancer: Science Review

Evidence From Humans
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Tallness and overweight during childhood have opposing effects on breast cancer risk
Hilakivi-Clarke, L., Forsen, T., Eriksson, J. G., Luoto, R., Tuomilehto, J., Osmond, C., Barker, D. J. Br J Cancer. 2001. 85:11, 1680-4.
Topic area
Early life exposures - Body size
Study design
Retrospective cohort
Funding agency
CRF; Komen; DOD
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Number in Cohort
Cohort: 3447
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women who were born at the Helsinki University Central Hospital during 1924-1933, who went to school in the city of Helsinki, and were still residents in Finland as 1971. Ex: women who emigrated and the date of emmigration was not recorded
Comment about participation selection
No cancer registry, cases are derived from the cause of hospitalization on the national hospital discharge register leading to misclassification Strengths: high participation rate; lengthy follow-up (24 years); anthropometric data were obtained from school records; analyzed breast cancer risk according to BMI and Height at 7 to 15 years of age Limitations: age at menarche was not recorded; did not have information on age at menopause, adult body weight, parity or age at first pregnancy and could not adjust for these confounders; used age 50 as the menopausal cut-off age
Exposure Investigated
Exposures investigated
Birthweight, birth length, maternal age, BMI, childhood height
How exposure was measured
Other:Birth records, Medical record (anthropometric data were obtained from school records)
Exposure assessment comment
Few cases in the referent category for birthweight
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.
Age, BMI, race, parity, menopausal status, 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. Analysis found no evidence of confounding by gestational age and placenta weight. Crude RR with 95% CI; birthweight: > 4000g versus <=2500g; birth length: >51cm versus <48cm, follow-up 1975-1995
Strength of associations reported
Birthweight: 1.9 (0.7-5.0); birth length: 1.4 (0.8-2.4)
Maternal age was not related to their daughters' breast cancer risk (results not shown).
Association between breast cancer risk and height at 15 years, >163cm vs <153cm, HR=1.9(1.2-3.2) trend p=0.005
Association between breast cancer risk and BMI at 15 years, <18 vs. >21.5, HR=1.7(1.0-2.7) trend p=0.03
Results Comments
High birth weight and long body at birth were associated with increased risk of the disease, although the association did not reach statistical significance. No significant association between BMI and breast cancer risk amongst girls 15 years of age, although women who developed breast cancer on average had lower BMIs than other girls
Author address
Lombardi Cancer Center, Georgetown University, Washington, DC 20007, USA.