Background: Alcohol is a recognized risk factor for invasive breast cancer, but few studies involve African American women. Methods: The current analysis included 22,338 women (5,108 cases of invasive breast cancer) from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. The association between number of alcoholic drinks per week (dpw) and breast cancer was estimated using logistic regression, adjusting for potential confounders, and stratifying by breast cancer subtype. Results: Approximately 35% of controls were current drinkers at interview. Women who reported current drinking of 14 dpw had an elevated risk of breast cancer compared with light drinkers (>0-<4 dpw) [adjusted OR (ORadj), 1.33; 95% confidence interval (CI), 1.07-1.64]. We observed elevated risk among women drinking 7 dpw for ER [ORadj, 1.31; 95% CI, 1.00-1.72], PR [ORadj, 1.28; 95% CI, 1.00-1.63], HER2 [ORadj, 1.36; 95% CI, 1.09-1.70], and triple-negative [ORadj, 1.39; 95% CI, 0.98-2.00] molecular subtype. Among receptor-positive cases, ORs remained elevated but attenuated relative to receptor-negative cases. Sensitivity analysis of age-defined windows of exposure (<30 years, 30-49, 50 years of age) did not reveal variation in patterns of association. Risk associated with alcohol intake did not vary significantly by oral contraceptive use, smoking status, or menopausal status. Conclusions: Among African American women, similar to women of European descent, drinking 7 alcoholic dpw was associated with an increased risk of breast cancer regardless of subtype. Impact: Alcohol intake is a modifiable risk factor for breast cancer, and reduced intake among African American women should be encouraged.
Bibliographical noteFunding Information:
Grant Support This work was supported by the National Institutes of Health: P01 CA151135 (to C.B. Ambrosone, J.R. Palmer, and A.F. Olshan), R01 CA058420 (to L. Rosenberg), UM1 CA164974 (to L. Rosenberg and J.R. Palmer), R01 CA098663 (to J.R. Palmer), R01 CA100598 (to C.B. Ambrosone), UM1 CA164973 (to L.N. Kolonel), R01 CA54281 (to L.N. Kolonel), P50 CA58223 (to M.A. Troester and A.F. Olshan), U01 CA179715 (to M.A. Troester and A.F. Olshan); and by the Komen for the Cure Foundation, the Breast Cancer Research Foundation (to C.B. Ambrosone); and the University Cancer Research Fund of North Carolina.