Cancer linked to Alzheimer disease but not vascular dementia

Objective: To investigate whether cancer is associated with Alzheimer disease (AD) and vascular dementia (VaD). Methods: Cox proportional hazards models were used to test associations between prevalent dementia and risk of future cancer hospitalization, and associations between prevalent cancer and risk of subsequent dementia. Participants in the Cardiovascular Health Study–Cognition Substudy, a prospective cohort study, aged 65 years or older (n 3,020) were followed a mean of 5.4 years for dementia and 8.3 years for cancer. Results: The presence of any AD (pure AD mixed AD/VaD; hazard ratio [HR] 0.41, 95% confidence interval [CI] 0.20–0.84) and pure AD (HR 0.31, 95% CI 0.12–0.86) was associated with a reduced risk of future cancer hospitalization, adjusted for demographic factors, smoking, obesity, and physical activity. No significant associations were found between dementia at baseline and rate of cancer hospitalizations for participants with diagnoses of VaD. Prevalent cancer was associated with reduced risk of any AD (HR 0.72;95%CI 0.52–0.997) and pure AD (HR 0.57;95% CI 0.36–0.90) among white subjects after adjustment for demographics, number of APOE 4 alleles, hypertension, diabetes, and coronary heart disease; the opposite association was found among minorities, but the sample size was too small to provide stable estimates. No significant association was found between cancer and subsequent development of VaD. Conclusions: In white older adults, prevalent Alzheimer disease (AD) was longitudinally associated with a reduced risk of cancer, and a history of cancer was associated with a reduced risk of AD. Together with other work showing associations between cancer and Parkinson disease, these findings suggest the possibility that cancer is linked to neurodegeneration.Supported by contract numbers N01-HC-85079 through N01-HC- 85086, N01-HC-35129, N01 HC-15103, N01 HC-55222, N01-HC- 75150, and N01-HC-45133, and grant U01 HL080295 from the National Heart, Lung, and Blood Institute, with additional contribution from the National Institute of Neurological Disorders and Stroke, grants 5 R01 AG15928-02, P50-AG05681, and P01-AG03991 from the National Institute on Aging of the NIH, Bethesda, MD, the Charles and Joanne Knight Alzheimer Research Initiative of the Washington University Alzheimer’s Disease Research Center, St. Louis, MO, and the Postdoctoral Program of 1UL1RR024992-01 from the National Center for Research Resources