Environment and Breast Cancer: Science Review

Evidence From Humans
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Waist-hip ratio and breast cancer risk in urbanized Nigerian women
Adebamowo, C. A., Ogundiran, T. O., Adenipekun, A. A., Oyesegun, R. A., Campbell, O. B., Akang, E. E., Rotimi, C. N., Olopade, O. I. Breast Cancer Research. 2003. 5:2, R18-24.
Topic area
Body size
Study design
Population based case-control (cases from hospital, controls from community)
Funding agency
Other: Falk Medical Research Trust
Study Participants
Number of Cases
234 (mostly advanced disease, no screening in population)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 273
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Over 18 yrs at baseline, cancer free at recruitment, urban resident and diagnosed with histologically confirmed breast cancer between 3/98 and 8/2000 (cases) Ex: Rural resident
Comment about participation selection
Strengths: Body measurements were taken by trained nurse practitioners; in person interviews; high participation rate especially amongst controls; breast cancers were histologically confirmed; analyzed the association between breast cancer risk and body size in a population that tends to present breast cancer at a young age and at a later stage Limitations: Small study with few obese participants; many cases were excluded due to rural residence; cases and controls were not matched; cases were hospital based while controls were population based; relatively few confounders
Exposures investigated
Height, weight, BMI, waist circumference, hip circumference, WHR
How exposure was measured
Questionnaire, in person Anthropometric measurement, researcher-administered
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
African 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: age, age at first pregnancy, height, and age at menarche
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 premenopausal breast cancer and height, continuous per cm, OR=1.03(1.00-1.07) trend p=0.07 (age adjusted only)
Association between premenopausal breast cancer and WHR, >0.85 vs. <0.77, OR=1.80(0.85-3.81) trend p=0.13
Association between postmenopausal breast cancer and height, continuous per cm, OR=1.07(1.02-1.13) trend p=0.01 (age adjusted only)
Association between postmenopausal breast cancer and weight, continuous per kg, OR=1.02(1.00-1.04) trend p=0.07 (age adjusted only)
Association between postmenopausal breast cancer and BMI, continuous per unit, OR=1.02(0.97-1.08) trend p=0.48 (age adjusted only)
Association between postmenopausal breast cancer and WHR, >0.85 vs. <0.77, OR=2.67(1.05-6.80) trend p=0.04
BACKGROUND: The aim of this study was to examine the relationship between waist-hip ratio and the risk of breast cancer in an urban Nigerian population. METHODS: Between March 1998 and August 2000, we conducted a case-control study of hospital-based breast cancer patients (n = 234) and population-based controls (n = 273) using nurse interviewers in urban Southwestern Nigeria. RESULTS: Multivariable logistic regression showed a significant association between the highest tertile of waist-hip ratio and the risk of breast cancer (odds ratio= 2.67, 95% confidence interval = 1.05-6.80) among postmenopausal women. No association was found in premenopausal women. CONCLUSION: The present study, the first in an indigenous African population, supports other studies that have shown a positive association between obesity and breast cancer risk among postmenopausal women.