Environment and Breast Cancer: Science Review


Evidence From Humans
 
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Impact of established risk factors for breast cancer in nulligravid Japanese women
Hirose, K., Tajima, K., Hamajima, N., Takezak, T., Inoue, M., Kuroishi, T., Miura, S. Breast Cancer. 2003. 10:1, 45-53.
Topic area
Body size - Physical Activity
Study design
Other: case-referent
Funding agency
Ministry of Health, Labor and Welfare, Japan
Study Participants
Number of Cases
2,032 (1,129 pre) (903 post)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Referent: 17,848 (11,226 pre) (6,622 post)
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: participants of the Hospital-Based Epidemiologic Research Program at Aichi Cancer Center; first-visit outpatients at the Aichi Cancer Center Hospital in Japan between 1/89 and 12/99; completed a self-administered questionnaire; age 30 or older; breast cancer cases diagnosed within 6 months after the initial visit by histological examination Ex: outpatients who visited the hospital while the interviewer was absent; women under 30 years of age; women with medical menopause; breast cancer cases diagnosed after 6 months of initial hospital visit; women diagnosed with a previous cancer
Comment about participation selection
Strengths: large case-referent study with many cases; cases were histologically confirmed; questionnaires were reviewed by trained interviewers; analyzed breast cancer risk by anthropometric factors stratified by parity and menopausal status; analyzed breast cancer risk by physical activity stratified by parity and menopausal status; data were collected before breast cancer diagnoses Limitations: many excluded participants; self-administered questionnaires; self-reported anthropometric and physical activity data; only 2 cases of postmenopausal nulligravid women with a family history of breast cancer; hospital based case-referent study which introduces a possible bias in non-cancer patients; referents were not matched to cases; did not obtain information on the reasons for nulliparity in nulligravid women
Exposure Investigated
Exposures investigated
Height, weight, weight at age 20 years, BMI, BMI at age 20 years, physical inactivity
How exposure was measured
Questionnaire, self-administered
Exposure assessment comment
Self-reported anthropometric and physical activity data
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
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, year of hospital visit, age at menarche, menstrual regularity throughout the womens' 20s, family history, 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.
No
Description of major analysis
Effect modifiers: parity and menopausal status
Strength of associations reported
Association between postmenopausal breast cancer risk in parous women and height, >159 cm vs. <150cm, OR=1.48(1.12-1.95) trend p<0.001
Association between postmenopausal breast cancer risk in nulligravid women and height, >159 cm vs. <150cm, OR=2.40(1.21-4.79) trend p=0.02
Association between postmenopausal breast cancer risk in parous women and weight, >57 kg vs. <47 kg, OR=1.84(1.47-2.29) trend p<0.001
Association between postmenopausal breast cancer risk in parous women and BMI, >25 vs. <22, OR=1.83(1.51-2.21) trend p<0.001
Association between postmenopausal breast cancer risk in nulligravid women and BMI, >25 vs. <22, OR=1.96(1.09-3.54) trend p=0.04
Inverse association between premenopausal breast cancer in parous women and physical activity, >3-4 times/mo. vs. none or occasionally, OR=0.83(0.70-0.98)
Inverse association between postmenopausal breast cancer in parous women and physical activity, >3-4 times/mo. vs. none or occasionally, OR=0.76(0.64-0.92)
Results Comments
No association between premenopausal breast cancer risk in parous or nulligravid women and anthropometric factors
Controls participation rate
Greater than 70% (referents 98%)