Abstract C86: Active smoking and breast cancer risk among Hispanic and non-Hispanic white women from the Breast Cancer Health Disparities Study
Authors: Connor Avonne E. , Baumgartner Kathy B. , Baumgartner Richard N. , Pinkston Christina M. , Boone Stephanie D. , John Esther M. , Torres- Mejía Gabriela , Hines Lisa M. , Giuliano Anna R. , Wolff Roger K. , Slattery Martha L. 
Published: May 2015

Abstract
The association between smoking and breast cancer has been extensively evaluated in epidemiological studies. Some, but not all studies found a positive association between smoking and breast cancer risk, especially among women with long smoking duration. Few studies have included Hispanic women. We evaluated the interaction between active smoking exposure and ethnicity using data from the Breast Cancer Health Disparities Study, a consortium of three population-based case-control studies including U.S. non-Hispanic whites (NHW) (1,525 cases; 1,593 controls), U.S. Hispanics/Native Americans (1,265 cases; 1,495 controls), and Mexican women (990 cases; 1,049 controls). Using multivariable logistic regression, odds ratios (ORs) and 95% confidence intervals (CI) were calculated to estimate the risk of breast cancer associated with active smoking exposure and assess differences in associations by ethnicity. We also tested for interaction effects between smoking and ethnicity by menopausal status and by history of alcohol use. Assessment of tobacco usage and active smoking exposures by ethnicity showed that there were significant (p value &lt; 0.001) differences between NHW, Hispanic/Native American, and Mexican women with regard to smoking status, total pack-years, total number of smoking years, and average number of cigarettes/day, with women from Mexico smoking fewer cigarettes than women living in the U.S. Risk was increased only among Mexican women who were former smokers (OR, 1.43; 95% CI 1.04-1.96, p interaction=0.03) or who smoked for more than 30 years (OR, 1.95; 95% 1.13-3.35, p interaction=0.04), compared to never smokers. No significant associations were observed among NHW or Hispanic/Native American women. Among NHW premenopausal women, increased breast cancer risk was associated with smoking 20 cigarettes or more/day (OR, 1.61; 95% CI 1.07-2.41, p interaction=0.02), whereas for NHW postmenopausal women the association with the same risk category was null. Additionally, we observed positive associations with breast cancer risk among postmenopausal women from Mexico who were former smokers (OR, 1.65; 1.09-2.50, p interaction=0.003) or who smoked for more than 30 years (OR, 2.13; 95% CI 1.18-3.86, p interaction=0.04). Lastly, there was a significant positive association found among Mexican women who were former smokers with a history of alcohol use (OR, 2.30, 95% CI 1.01-5.21, p interaction=0.003), while there were no significant associations found among nondrinkers who were Mexican, Hispanic/Native American, or NHW in the same risk category for smoking status. Our data suggest that the association between smoking and breast cancer risk is significant among women from Mexico. Furthermore, menopausal status and history of alcohol use should be examined for their potential modifying effects when evaluating the association between cigarette smoking, ethnicity, and breast cancer risk.
Citation Format: Avonne E. Connor, Kathy B. Baumgartner, Richard N. Baumgartner, Christina M. Pinkston, Stephanie D. Boone, Esther M. John, Gabriela Torres- Mejía, Lisa M. Hines, Anna R. Giuliano, Roger K. Wolff, Martha L. Slattery. Active smoking and breast cancer risk among Hispanic and non-Hispanic white women from the Breast Cancer Health Disparities Study. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C86. doi:10.1158/1538-7755.DISP13-C86