Background: No study on the long-term incidence of Alzheimer's disease (AD) and related dementias (ADRD) has been reported in women with breast cancer by vascular diseases.
Objective: To determine the risk of ADRD in association with cardiovascular diseases (CVD), stroke, hypertension, and diabetes in women with breast cancer.
Methods: Study identified 246,686 women diagnosed with breast cancer at age≥65 years in 1991-2015 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Women were free of ADRD at the time of cancer diagnosis and followed from 1991 to 2016.
Results: Cumulative incidence of AD over 26 years of follow-up varied from 10.7% to 13.6% by CVD, stroke, hypertension, and diabetes. Cumulative incidence of ADRD was higher in those with CVD (40.75%) versus no-CVD (31.32%), stroke (40.24%) versus no-stroke (31.34%), hypertension (33.06%) versus no-hypertension (30.47%), and diabetes (33.38%) versus no-diabetes (31.77%). After adjusting for confounders, those with CVD (hazard ratio:1.30, 95% CI: 1.27-1.33), stroke (1.50,1.47-1.54), hypertension (1.08,1.06-1.09), and diabetes (1.26,1.24-1.29) had significantly higher risks of developing ADRD. Women aged 80-84, and≥85 had 5- and 7-fold higher risks of AD than those aged 65-69. As compared to white women, black women had a significantly higher risk of AD (1.21, 1.16-1.27), whereas Asians/Pacific-Islanders had a significantly lower risk of AD (0.77, 0.71-0.83).
Conclusion: In women with breast cancer, CVD, stroke, hypertension, and diabetes were associated with a significantly higher risk of developing any ADRD combined. The risk of ADRD was higher in black women and lower in Asian/Pacific-Islanders than white women.
Keywords: Alzheimer’s disease; breast cancer; dementias; medicare; vascular diseases.