Link between alcohol intake, breast cancer risk confirmed in African American women

By Liz Meszaros, MDLinx
Published May 3, 2017

Key Takeaways

Like women of European descent, African American women who drink 7 or more alcoholic drinks per week (dpw) have an increased risk of breast cancer, regardless of subtype, according to results from a recent study published in the journal Cancer Epidemiology, Biomarkers & Prevention.

“Minority groups are often understudied because they represent a smaller proportion of study populations. This work avoided that limitation by working with a consortium of many different studies, including more than 20,000 black women,” said senior author Melissa Troester, PhD, a member of University of North Carolina Lineberger Comprehensive Cancer Center, and professor of epidemiology, UNC Gillings School of Global Public Health, Chapel Hill, NC. “We found that the patterns observed in other studies examining alcohol and breast cancer risk hold in black women, too.”

Dr. Troester and fellow researchers analyzed data from 22,338 women, with a total of 5,108 cases of invasive breast cancer, from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. They used logistic regression to estimate the association between the number of alcoholic dpw and breast cancer, which were then stratified according to breast cancer subtype.

They found that women who reported drinking ≥ 14 dpw had an elevated risk of breast cancer compared with those who were light drinkers, drinking more than 0 to < 4 dpw (adjusted OR [ORadj]: 1.33; 95% CI, 1.07-1.64].

When stratifying women by breast cancer subtype, researchers found that current drinkers of ≥ 7 dpw had an elevated risk of the following molecular subtypes:

  • 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).

In receptor-positive cases, OR was elevated but attenuated relative to receptor-negative cases.

Upon conducting a sensitivity analysis of age-defined windows of exposure, including < 30 years, 30 to 49 years, and greater ≥ 50 years, they found no variation in the patterns of association. Furthermore, the risks associated with alcohol consumption did not significantly vary according to oral contraceptive use, smoking status, or menopausal status.

These results highlight the importance of modification of modifiable risk factors—such as alcohol consumption.

“Overall, our findings among African American women mirror those reported in the literature for white women, namely that high levels of alcohol intake – more than one drink per day – are associated with increased breast cancer risk. Alcohol is an important modifiable exposure, and women who are concerned about their risk of breast cancer could consider reducing levels of exposure,” concluded Dr. Troester.

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