Breast cancer and diabetes mellitus-related mortality among U.S. adults: a 25-year CDC WONDER analysis (1999-2023).

Breast cancer (BC) and diabetes mellitus (DM) frequently coexist, posing significant clinical challenges. Evaluating long-term mortality trends helps assess the impact of healthcare practices and public health policies. This study examines mortality trends involving breast cancer and DM in US adults aged > 25, stratified by demographics and geography. We conducted a retrospective analysis of CDC WONDER mortality data from 1999 to 2023 for individuals aged ≥ 25 years. BC and DM were identified using ICD-10 codes C50 and E10-E14. Age-adjusted mortality rates (AAMR) per 100,000 were calculated. Joinpoint regression estimated annual percentage changes (APC) with 95% confidence intervals (CI). From 1999 to 2023, 79,139 deaths involving BC and DM. Overall, AAMR remained stable (AAPC 0.23; 95% CI, -0.002 to 0.475, p > 0.05). Females had higher AAMR (2.42) than males (0.05). Non-Hispanic (NH) Blacks had the highest AAMR (2.69), followed by Hispanics (1.31), NH Whites (1.28). Older adults, rural residents, and the Midwest region had higher mortality. Mortality involving BC and DM has remained largely stable over two decades, but disparities by sex, age, race/ethnicity, and geography persist, highlighting the need for targeted interventions in high-risk populations. The online version contains supplementary material available at https://doi.org/10.1007/s40200-026-02074-4.