Environment and Breast Cancer: Science Review

Evidence From Humans
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The effect of body mass index and oestrogen receptor level on survival of breast cancer patients
Newman, S. C., Lees, A. W., Jenkins, H. J. International Journal of Epidemiology. 1997. 26:3, 484-90.
Topic area
Body size
Study design
Prospective cohort
Funding agency
Not reported
Study Participants
Number of Cases
244 deaths from breast cancer
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort:1169 (61% post)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women registered in the Northern Alberta Breast Cancer Registry between 1978 and 1989 Ex: women with advanced breast cancer disease; women with missing values for tumor size, number of positive axillary nodes, oestrogen receptor level, age, height, and weight; subjects who did not have axillary nodes removed
Comment about participation selection
Strengths: one of the few studies to examine the joint affects of BMI and oestrogen receptors on the survival of breast cancer; obtained patients from a cancer registry with a population-based information system; annual follow-up; anthropometric data were obtained by trained staff; obtained stage, size of tumor, number of positive nodes and oestrogen receptor from breast cancer patients; analyzed death from breast cancer by BMI and number of positive nodes Limitations: low participation rate (34%); did not stratify results by menopausal status
How exposure was measured
Medical record Anthropometric measurement, researcher-administered
Breast cancer outcome investigated
Mortality from 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.
Adequately controlled, Confounders: not reported
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
Effect modifiers: number of positive nodes Follow-up: 4.4 years
Strength of associations reported
Increased risk of breast cancer death in women with a high BMI, >28.9 vs <22.8, HR=2.47(1.17-5.22)
Increased risk of breast cancer death in women with a high BMI and no positive nodes, >28.9 vs <22.8, HR=2.5(1.2-5.2)
Author address
Department of Psychiatry, Mackenzie Health Sciences Centre, University of Alberta, Edmonton, Canada.