Abstract A120: Aspirin use and risk of multiple myeloma among US Black women

Abstract Introduction: Multiple myeloma is a fatal cancer of the blood that is 2-3 more times common in Black men and women than in non-Hispanic white individuals. Critical gaps exist in the understanding of modifiable risk factors for myeloma, especially among underrepresented populations. Aspirin blocks B-cell activation mediated by nuclear factor (NF)-κB and targets pro-inflammatory cytokines and thus has strong biological plausibility for reducing risk of myeloma; however, few epidemiologic studies have evaluated the possible association between aspirin use and multiple myeloma risk, with mixed results. Further, all prior studies included majority white populations. Methods: We evaluated the association between aspirin use and risk of multiple myeloma in the Black Women’s Health Study (BWHS), a prospective cohort of 59,000 self-identified Black women from across the U.S. who have been followed biennially since 1995. Participants were ages 21-69 (mean age, 38) at baseline. We queried aspirin use (at least 3 times per week) on each biennial questionnaire and treated aspirin use as time-varying in analyses. Cancer diagnoses were confirmed via medical record review and linkage to state cancer registries. We fit Cox proportional hazards regression models, stratified by age, to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of multiple myeloma among current or past aspirin users compared to non-users. Multivariable models were additionally adjusted for body mass index (BMI), height, educational attainment, alcohol consumption, smoking history, and physical activity. Results: Among 57,007 BWHS participants with no prior history of cancer in 1995, we confirmed 296 incident diagnoses of multiple myeloma over 26 years of follow-up. Compared to non-users of aspirin, age-adjusted HRs for past and current users were 1.25 (95% CI: 0.93, 1.67) and 1.17 (95% CI: 0.87, 1.59), respectively. Results were slightly attenuated in models adjusted for potential confounders, including BMI; corresponding multivariable-adjusted HRs were 1.20 (95% CI: 0.89, 1.62) and 1.06 (95% CI: 0.78, 1.45). Conclusions: Our preliminary findings do not support the hypothesis that aspirin may have a chemopreventive effect on multiple myeloma risk in Black women. Analyses are ongoing to evaluate whether duration of use may be associated with risk. Further investigation of potentially modifiable risk factors for multiple myeloma is essential to reducing the incidence of this cancer and closing the gap in racial disparities in multiple myeloma. Citation Format: Kimberly A. Bertrand, Etienne X. Holder, Julie R. Palmer. Aspirin use and risk of multiple myeloma among US Black women [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A120.