Cigarette smoking and risk of breast carcinoma in situ.
BACKGROUND
Although the associations with cigarette smoking have been explored extensively for invasive breast cancer, the relation to in situ cancer has not previously been examined in depth.


METHODS
We analyzed data from a population-based case-control study of women living in Wisconsin, Massachusetts, and New Hampshire. Eligible cases of incident breast carcinoma in situ were reported to statewide registries in 1997-2001 (n = 1878); similarly aged controls (n = 8041) were randomly selected from population lists. Smoking history and other risk factor information were collected through structured telephone interviews. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated from logistic regression models adjusting for potential confounders.


RESULTS
In multivariate models, the OR for breast carcinoma in situ among current smokers was 0.8, compared with never-smokers (95% CI = 0.7-1.0). Risk estimates increased towards the null with greater time since smoking cessation. Odds ratios were also less than 1.0 among women who initiated smoking in adolescence (OR = 0.8) or after a full-term birth (OR = 0.7), relative to women who never smoked. The reduced odds ratios associated with current smoking were strongest among women with annual screening mammograms (OR = 0.7; 95% CI = 0.6-0.9). Odds ratios were not less than 1.0 among current smokers without a recent screening mammogram (1.3; 0.9-2.0).


CONCLUSIONS
Our findings suggest an inverse association between current smoking and risk of breast carcinoma in situ among women undergoing breast cancer screening.
Trentham-Dietz
Amy
A
University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, Madison, Wisconsin 53726, USA. trentham@wisc.edu
Nichols
Hazel B
HB
Egan
Kathleen M
KM
Titus-Ernstoff
Linda
L
Hampton
John M
JM
Newcomb
Polly A
PA
D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007407:Interviews as Topic; D016015:Logistic Models; D008327:Mammography; D008875:Middle Aged; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D016540:Smoking Cessation / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology