Due to racial bias among participants in many genetic studies, the risks of developing various diseases are less clear in ethnicities outside those with a Caucasian background. For instance, alcohol is an established risk factor for breast cancer—however, most studies have been conducted in predominantly white populations. Now, in a large study of African-American women, led by investigators at the University of North Carolina (UNC), researchers found that alcohol consumption was associated with an increased risk of breast cancer—indicating that African-American women, like white females, may benefit from limiting their alcohol intake.
“Alcohol is an important modifiable exposure, whereas many other risk factors are not,” explained senior study investigator Melissa Troester, Ph.D., professor of epidemiology and director of the Center for Environmental Health and Susceptibility in the Gillings School of Global Public Health at UNC. “Women who are concerned about their risk of breast cancer could consider reducing levels of exposure.”
The findings from the new study were published recently in Cancer Epidemiology, Biomarkers & Prevention in an article entitled “Alcohol Intake and Breast Cancer Risk in African American Women from the AMBER Consortium.”
In this new study, the researchers wanted to discern whether alcohol raises risk for African-American women by assessing participants in a large study that solely enrolled African-American women. Dr. Troester and her colleagues enrolled 22,338 women from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium, which encompasses four large epidemiologic studies of breast cancer. The study participants reported their alcohol intake via a questionnaire, and researchers used logistic regression analysis to estimate the association between alcohol consumption and cases of breast cancer.
Findings from the analysis showed that women who drank seven or more drinks per week showed an increased risk of almost all subtypes. Moreover, women who drank 14 or more alcoholic beverages per week were 33% more likely to develop breast cancer than women who consumed four or fewer drinks per week.
Interestingly, the researchers found that 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% 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 stated 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 co-morbidities, such as diabetes, that influenced them to avoid alcohol.
While the research team noted that a limitation of the study was that it included relatively few women who drank heavily, making those findings less statistically significant, they did point out that their results were consistent with previous research indicating increased risk for the highest levels of alcohol consumption. Furthermore, results of this study indicate that the same risk factors that have been documented in previous research apply to black women as well.
“Understanding the impact of these various risk factors could help narrow the disparity in breast cancer incidence and mortality,” Dr. Troester concluded.