Examining the Impact of Alcohol Consumption and Cancer Risk

A study connects alcohol consumption with an increased risk of most types of breast cancer among African-American women.

For the past decade, researchers have known that alcohol raises the risk of breast cancer. But the studies that suggested that connection were conducted in predominantly white populations, leaving some unanswered questions about whether alcohol consumption would carry the same increased risks in African-American women.

In order to assess their risk, Melissa A. Troester, PhD, a professor of epidemiology and director of the Center for Environmental Health and Susceptibility in the Gillings School of Global Public Health at the University of North Carolina, lead a study analyzing data on 22,338 women from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium, which encompasses four large epidemiologic studies of breast cancer.

Results of the analysis by Dr. Troester and her colleagues were published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

Their analysis found that women who consumed seven or more drinks per week showed an increased risk of almost all subtypes of breast cancer. Women who drank 14 or more alcoholic beverages per week were 33 percent more likely to develop breast cancer than women who consumed four or fewer drinks per week.

The study results indicate that African-American women, like white women, may benefit from limiting alcohol, Dr. Troester said.

“Alcohol is an important modifiable exposure, whereas many other risk factors are not,” she said. “Women who are concerned about their risk of breast cancer could consider reducing levels of [alcohol] exposure.”

The study also shed light on some interesting differences between black and white women and alcohol. Overall, Dr. Troester said, black women drink less alcohol than white women, with previous research suggesting a range of reasons from religious restrictions to health restrictions.

In this study, 45 percent of the women were “never drinkers,” and researchers found that the “never drinkers” were more likely to develop breast cancer than the light drinkers. Dr. Troester said that they did not identify the causes for increased risk in never drinkers, but previous studies finding similar elevated risk in never drinkers implicate the comorbidities, such as diabetes, that influenced them to avoid alcohol.

Dr. Troester said that overall, black and white women share the same risk factors for breast cancer – weight, reproductive history, oral contraceptive use, and family history among them. This study conclusively adds alcohol to the list of shared risk factors.

“Understanding the impact of these various risk factors could help narrow the disparity in breast cancer incidence and mortality,” Dr. Troester said.

Dr. Troester said a limitation of the study is that it included relatively few women who drank heavily, making those findings less statistically significant. However, she said this study’s results are consistent with previous research indicating increased risk for the highest levels of alcohol consumption.

This study was funded by the National Institutes of Health, the Komen for the Cure Foundation, the Breast Cancer Research Foundation, and the University Cancer Research Fund of North Carolina.