Environment and Breast Cancer: Science Review

Evidence From Humans
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Risk factors for breast carcinoma in Singaporean Chinese women: the role of central obesity
Ng, E. H., Gao, F., Ji, C. Y., Ho, G. H., Soo, K. C. Cancer. 1997. 80:4, 725-31.
Topic area
Body size
Study design
Other: case-control: hospital based cases and population based screening controls
Funding agency
Other: National Medical Research Council, Singapor
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Control: 882
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Age at baseline 45 to 69 years, underwent surgery for Stage 1 or 2 breast carcinoma at the study hospital from 1994 to 1996 (cases), and attended a population-based screening mammography program with 42% participation rate (controls) Ex: Pregnant women and women with a previous diagnosis of cancer
Comment about participation selection
Strengths: Anthropometric measurements were performed by a small group of trained nurses, focuses on Singaporeans whose breast cancer incidence rates have doubled over the past 25 years Limitation: possible recall bias, and few premenopausal cases
Exposures investigated
Weight, height, BMI, W/H ratio
How exposure was measured
Questionnaire, self-administered
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Singaporean Chinese Women
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: W/H ratio, age, menopausal status, age at menarche, parity, number of births, age at last birth, HRT use, oral contraceptive use, family history of breast cancer, lactation, smoking status, height, weight, and BMI
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: menopausal status
Strength of associations reported
Association between breast cancer risk and Waist/Hip ratio, 0.86 vs. <0.75, OR= 9.18(4.8-17.5) trend p <0.0001
Association between premenopausal breast cancer risk and Waist/Hip ratio, 0.86 vs. <0.75, OR=7.81(2.8-21.9) trend p=0.003
Association between postmenopausal breast cancer risk and Waist/Hip ratio, 0.86 vs. <0.75, OR=8.19(3.4-19.5) trend p<0.0001
Association between breast cancer risk in parous women and Waist/Hip ratio, 0.86 vs. <0.75, OR=9.19(4.5-19.0) trend p<0.0001
Association between breast cancer risk and height, >159cm vs. <150cm, OR=2.32(1.4-3.9) trend p=0.003
Results Comments
No association between breast cancer risk and BMI
Author address
Singapore Cancer Center and Department of Surgery, Singapore General Hospital, Republic of Singapore.
Controls participation rate
Less than 70% (42% recruitment into screening prog