The association of alcohol consumption with mammographic density in a multiethnic urban population.

Background: Alcohol consumption is associated with higher breast cancer risk. While studies suggest a modest association between alcohol intake and mammographic density, few studies have examined the association in racial/ethnic minority populations.

Methods: We assessed dense breast area and total breast area from digitized film mammograms in an urban cohort of African American (42%), African Caribbean (22%), white (22%), and Hispanic Caribbean (9%) women (n = 189, ages 40-61). We examined the association between alcohol intake and mammographic density (percent density and dense area). We used linear regression to examine mean differences in mammographic density across alcohol intake categories. We considered confounding by age, body mass index (BMI), hormone contraceptive use, family history of breast cancer, menopausal status, smoking status, nativity, race/ethnicity, age at first birth, and parity.

Results: Fifty percent currently consumed alcohol. Women who consumed >7 servings/week of alcohol, but not those consuming ≤7 servings/week, had higher percent density compared to nondrinkers after full adjustments (servings/week >7 β = 8.2, 95% Confidence Interval (CI) 1.8, 14.6; ≤7 β = -0.5, 95% CI -3.7, 2.8). There was a positive association between high alcohol intake and dense area after full adjustments (servings/week >7 β = 5.8, 95% CI -2.7, 14.2; ≤7 β = -0.1, 95% CI -4.4, 4.2). We did not observe race/ethnicity modification of the association between alcohol intake and percent density. In women with a BMI of <25 kg/m(2), drinkers consuming >7 servings/week of alcohol had a = 17% increase in percent density compared to nondrinkers (95% CI 5.4, 29.0) and there was no association in women with a BMI ≥ 25 kg/m(2) (BMI ≥ 25-30 kg/m(2) > 7 β = 5.1, 95% CI -8.5, 18.7 and BMI > 30 kg/m(2) > 7 β = 0.5, 95% CI -6.5, 7.5) after adjusting for age and BMI (continuous).

Conclusion: In a racially/ethnically diverse cohort, women who consumed >7 servings/week of alcohol, especially those with a BMI < 25 kg/m(2), had higher percent density.