Risk of Alzheimer's disease incidence attributable to vascular disease in the population

Background: Although Alzheimer's disease (AD) is a neurodegenerative disorder, there is growing interest in the influence of vascular factors on its incidence. Methods: In a population-based longitudinal epidemiological study, we fit Cox proportional hazard models to examine the risk of incident dementia and AD associated with self-reported vascular disease. The population-attributable risk percent (percent of the incidence of dementia and AD in the population that would be eliminated if vascular disease was eliminated) was calculated using the adjusted hazard ratios (HR). Results: Of 822 eligible participants, 94 individuals developed incident dementia, with 79 having AD (probable/possible AD) during the follow-up period of on average 8 years. Stroke/transient ischemic attack history was associated with incident dementia (HR = 2.6) as well as AD (HR = 2.4) among non-apolipoprotein E epsilon 4 carriers. Conclusions: At the community level, the risk of dementia could be potentially reduced by 10.8% by eliminating overt cerebrovascular disease, and the risk of AD by 9.1% for non-apolipoprotein E epsilon 4 carriers. (C) 2011 The Alzheimer's Association. All rights reserved.