Associations Between Vascular Diseases and Alzheimer's Disease or Related Dementias in a Large Cohort of Men and Women with Colorectal Cancer.

BACKGROUND

Long term risk of Alzheimer's disease (AD) and related dementias (ADRD) associated with vascular diseases in people with colorectal cancer is unknown.

OBJECTIVE

To determine the risk of ADRD in association with cardiovascular diseases (CVD), stroke, hypertension, and diabetes in a cohort of patients with colorectal cancer.

METHODS

This retrospective cohort study consisted of 210,809 patients diagnosed with colorectal cancer at age≥65 years in 1991-2015 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database with follow-up from 1991-2016, who were free of any ADRD at the baseline (<12 months prior to or < 30 days after the date of cancer diagnosis).

RESULTS

The crude 26-year cumulative incidence of total ADRD in men and women with colorectal cancer was higher in those with versus without CVD (31.92% versus 28.12%), with versus without stroke (39.82% versus 26.39%), with versus without hypertension (31.88% versus 24.88%), and with versus without diabetes (32.01% versus 27.66%). After adjusting for socio-demographic and tumor factors, the risk of developing ADRD was significantly higher in patients with CVD (adjusted hazard ratio: 1.17, 95% confidence intervals: 1.14-1.20), stroke (1.65, 1.62-1.68), hypertension (1.07, 1.05-1.09), and diabetes (1.26, 1.24-1.29) versus persons without. For those with 1, 2, 3 and 4 vascular diseases present versus absent, the risk of AD increased from 1.12 (1.07-1.16) to 1.31 (1.25-1.36), 1.66 (1.57-1.75), and 2.03 (1.82-2.27).

CONCLUSION

In older patients with colorectal cancer, a significant dose-response relationship was observed between an increasing number of these vascular diseases and the risk of all types of dementia.