Evidence suggests that
aspirin use reduces the occurrence of colorectal
neoplasia. Few studies have investigated the association among Black Americans, who are disproportionately burdened by the disease. We assessed
aspirin use in relation to colorectal
adenoma among Black women. The Black Women's Health Study is a prospective cohort of self-identified Black American women established in 1995. Participants reported regular
aspirin use on baseline and follow-up questionnaires. Beginning in 1999, participants reported undergoing a colonoscopy or sigmoidoscopy, the only procedures through which colorectal
adenomas can be diagnosed. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between
aspirin use and colorectal
adenoma among 34 397 women who reported at least 1 colonoscopy or sigmoidoscopy. From 1997 through 2018, 1913 women were diagnosed with an
adenoma. Compared to nonaspirin users, regular users had 14% (OR = 0.86, 95% CI: 0.78-0.95) lower odds of
adenoma. The odds of
adenoma decreased with increasing duration of
aspirin use (≥10 years: OR = 0.80, 95% CI: 0.66-0.96). Initiating
aspirin at a younger age was associated with a reduced
adenoma occurrence (age < 40 years at initiation: OR = 0.69, 95% CI: 0.55-0.86). Regular
aspirin use was associated with a decreased odds of colorectal
adenoma in our study of Black women. These findings support evidence demonstrating a chemopreventive impact of
aspirin on colorectal
neoplasia and suggest that
aspirin may be a useful prevention strategy among US Black women.