Environment and Breast Cancer: Science Review

Evidence From Humans
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Population attributable risk for breast cancer: diet, nutrition, and physical exercise. [see comment] [erratum appears in J Natl Cancer Inst 2000 May 17;92(10):845]
Mezzetti, M., La Vecchia, C., Decarli, A., Boyle, P., Talamini, R., Franceschi, S. Journal of the National Cancer Institute. 1998. 90:5, 389-94.
Topic area
Physical Activity - Body size
Study design
Retrospective case-control study
Funding agency
Other: Associazione Italiana per la Ricerca sul Ca
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 2,588
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: Participants of the Italian National Research Council Applied Project; age 23-74 at baseline (cases), age 20-74 at baseline (controls), diagnosed with breast cancer in one of six areas in Italy between 6/91 and 4/94 (cases), women with no previous history of cancer, and admitted to a hospital in the same catchment areas of the case subjects for acute conditions (controls) Ex: Women admitted for gynecologic, hormonal, neoplastic diseases, or diseases related to risk factors for breast cancer and women over 74 years old
Comment about participation selection
Strengths: Less than 4% of case and control subjects refused to participate, interviews were conducted by trained interviewers, study assessed dietary intake, large case-control study, and all interviews were done in a hospital which should improve the comparability of the information collected, analyzed breast cancer risk by BMI and physical activity according to menopausal status Limitations: Not a population based case-control study, retrospective study, physical activity assessment was not based on an objective quantification of total energy expenditure, anthropometric data self-reported, and not clear that hospitalization conditions for controls were unrelated to BMI or physical activity
Exposure Investigated
Exposures investigated
BMI and physical activity
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Anthropometric data self-reported
Statistical Analysis
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: age, center, education, calorie intake, menopausal status, B-carotene intake, Vitamin E intake, Alcohol consumption, physical activity, 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
Low vs high physical activity: OR= 1.50 (1.16-1.93), Population attributable risk (PAR)=11.6%, Postmenopausal women OR=1.61(1.16-2.23)
BMI related to increased risk in postmenopausal women: >26.6 vs <23.3, OR=1.22 (1.03-1.46), Population attributable risk (PAR) = 10%
Results Comments
Physical activity result not statistically significant for premenopausal women BMI unrelated to risk in premenopausal women
Author address
Istituto Europeo di Oncologia, Milan, Italy.
Reviewers Comments
This paper is part of a subset of papers that uses the same base set as several other studies: Tavani A, Braga C, La Vecchia C, Parazzini F, Talamini R, Franceschi S. 1998. Height and breast cancer risk.[see comment]. Eur J Cancer. 34 (4): 543-547. Tavani A, Gallus S, La Vecchia C, Negri E, Montella M, Dal Maso L et al. 1999. RIsk factors for breast cancer in women under 40 years. Eur j Cancer. 35 (9):1361-1367