Environment and Breast Cancer: Science Review

Evidence From Humans
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Association between N-acetyltransferase 2 (NAT2) genetic polymorphism and development of breast cancer in post-menopausal Chinese women in Taiwan, an area of great increase in breast cancer incidence
Huang, C. S., Chern, H. D., Shen, C. Y., Hsu, S. M., Chang, K. J. International Journal of Cancer. 1999. 82:2, 175-9.
Topic area
Body size - Genetic variability
Study design
Hospital based case-control study
Funding agency
Other: National Science Council, Taiwan
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.
Pathologically confirmed primary breast cancer cases recruited from university hospital. Controls were a random sample of women from clinic in same hospital during same study period, free of all cancers.
Exposures investigated
BMI, Allele frequencies of NAT2, 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.
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 NAT2 genotype and breast cancer, including effect modification by BMI
Strength of associations reported
In adjusted model, slow (any combination of no-wild type alleles) acetylators showed an OR=1.81 (1.01-3.31)
Risk was greater in postmenopausal women (OR=2.31, CI: 1.01-5.47) but not premenopausal
Among slow acetylators, who are postmenopausal with BMI <25, adjusted OR=6.5 (CI:2.1-11.6)
Results Comments
Authors suggest that the effects of NAT2 are small, and only present if the effects of other risk factors are attenuated Could not explore relationship with smoking as few Taiwanese women smoked NAT2 effects may be present in postmenopausal women because it takes time for carcinogens to accumulate effective dose