Alcohol consumption and mammographic density in a multiethnic urban community

Background: Extensive epidemiologic evidence has observed a consistent modest association between alcohol intake and breast cancer risk. Less is known, particularly in multiethnic populations, about an association between alcohol consumption and mammographic density, a strong intermediate marker of breast cancer risk.

Purpose: To determine the association between alcohol consumption and mammographic density and to examine possible effect modification by ethnic group.

Methods: We conducted a study of alcohol consumption and mammographic density using a multiethnic sample composed of African Americans (n=81), African Caribbeans (n=42), Hispanic Caribbeans (n=18) and Caucasians (n=41) recruited at a mammography screening clinic in Brooklyn, New York (n=182). Mammographic density was measured using a computer-assisted thresholding program. Multiple linear regression models assessed the association between grams of alcohol consumed per week and percent mammographic density.

Results: After adjusting for age and body mass index (BMI), there were no differences in mammographic density among ethnic groups. Ethnicity was associated with current alcohol consumption and with amount consumed per week. Sixty-one percent of Caucasians participants reported current drinking, followed by African Americans (54%), African Caribbeans (38%) and Hispanic Caribbeans (29%). Alcohol consumption was positively associated with mammographic density after adjustment for age, BMI and education, but was not modified by ethnicity. On average, a daily drinker's percent mammographic density was 1.12% (95% CI 1.01, 1.24) higher than a woman who drank once per week.

Conclusion: This study adds to the growing evidence that alcohol consumption is associated with mammographic density. The association did not vary by ethnic group.