Environment and Breast Cancer: Science Review

Evidence From Humans
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Catechol-O-methyltransferase and breast cancer risk
Millikan, R. C., Pittman, G. S., Tse, C. K., Duell, E., Newman, B., Savitz, D., Moorman, P. G., Boissy, R. J., Bell, D. A. Carcinogenesis. 1998. 19:11, 1943-7.
Topic area
Body size - Genetic variability
Study design
Population based case-control
Funding agency
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Participants of the Carolina Breast Cancer Study. Histologically confirmed cases were identified through North Carolina cancer registry. Controls were frequency matched to cases by 5-year age interval and race, selected from North Carolina DMV and US Health Care Financing Administration.
Comment about participation selection
Comparable numbers of White and Black participants
Exposures investigated
BMI, COMT allele frequencies, used PCR-RFLP
How exposure was measured
Biological Questionnaire, in-person
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Sample included comparable numbers of White and African American 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
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
Logistic regression analysis of COMT genotype and cancer risk, including effect modification by BMI and physical activity
Strength of associations reported
Overall adjusted RR (CI) were 0.8 (0.6-1.1) for HL type and 0.8 (0.6-1.1) for LL type (the same)
No difference by Black and White women.
Using median of BMI of 27.8 as cutpoint, no association between BMI and genotype on BC risk stratified by menopausal status (i.e., no increased risk for postmenopausal women with >median BMI)
Physically inactive women with LL type showed decreased BC risk (premenopausal OR=0.5 (CI: 0.2-0.9) and postmenopausal OR=0.5 (CI: 0.3-0.9) compared to HH type, either active or inactive
Results Comments
Assessment of physical activity based on one question asking about regular activities in the last 3 months