A study of African American women found that drinking 7 or more alcoholic drinks a week was associated with an elevated risk for breast cancer of all subtypes.
A study of African American women found that drinking 7 or more alcoholic drinks per week was associated with an elevated risk for breast cancer of all subtypes. This is similar to the risk seen in white women.
“Although alcohol is an established risk factor for breast cancer, most studies have been conducted in predominantly white populations,” wrote study authors led by Melissa A. Troester, PhD, of the University of North Carolina at Chapel Hill. African Americans report less alcohol intake than white individuals, and have differing patterns of exposure to other breast cancer risk factors; “thus, it is important to understand the relationship between alcohol and breast cancer risk in context of other exposures.”
The new study included 22,338 women from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium; of those, there were 5,108 cases of invasive breast cancer, and the remaining patients were included as controls. The researchers estimated correlations between drinks per week (DPW) and breast cancer risk; the results were published in Cancer Epidemiology, Biomarkers & Prevention.
Of the full cohort, 45% of women were never drinkers, and 20.8% were past drinkers. Approximately 11% of both cases and controls reported consuming at least 4 DPW. Women who reported drinking at least 14 DPW had an elevated risk of breast cancer compared with light drinkers (between 0 and 4 DPW), with an adjusted odds ratio (OR) of 1.33 (95% CI, 1.07–1.64).
In an analysis stratified for hormone receptor status, consuming at least 7 DPW was associated with increased risk for each subtype. The OR for estrogen receptor (ER)-negative disease was 1.31 (95% CI, 1.00–1.72); for progesterone receptor (PR)-negative disease, the OR was 1.28 (95% CI, 1.00–1.63); for HER2-negative disease, the OR was 1.36 (95% CI, 1.09–1.70); and for triple-negative breast cancer, the OR was 1.39 (95% CI, 0.98–2.00). The associations were in the same direction for ER-positive, PR-positive, and HER2-positive breast cancer, but they were attenuated and non-significant.
There was no change in risk depending on oral contraceptive use, smoking status, or menopausal status. The analysis also showed that never-drinkers had an elevated risk of breast cancer compared with light drinkers, with an OR of 1.12 (95% CI, 1.02–1.24).
“Our findings support alcohol as a risk factor for breast cancer in African American women, where risk associations have been less well-studied,” the authors concluded. “Our results suggest that drinking cessation may be associated with a reduced risk of invasive breast cancer and may be a targetable public health intervention strategy among African American women.”