UC Irvine

Abstract Objective: To analyze common cardiovascular risk factors in relation to all-cause dementia risk in a cohort of oldest-old (90 years and older) participants. Background: Vascular diseases in middle life are commonly associated with an increased risk of dementia in later life. In contrast, we found that history of hypertension in the oldest-old was associated with a decreased risk of dementia. Whether this protective association is unique to hypertension or if other cardiovascular risk factors have similar effects is unknown. Design/Methods: Participants are from The 90+ Study, an ongoing population-based longitudinal study of people without dementia (DSM-IV). Participants were followed every 6 months for up to 10 years (average = 2.8 years) with dementia ascertained at each visit. We used Cox regression to estimate risk of dementia in relation to cardiovascular risk factors, using age as the time scale, dementia diagnosis as the outcome, and adjusting for gender and education. Results: At baseline, participants were on average 93 years old (range: 90–103) and most were women (71%). During follow-up, 224 (40%) participants developed dementia. The prevalence of vascular disease ranged from 6% for diabetes to 58% for hypertension. Congestive heart failure, heart valve disease, and stroke were significantly associated with an increased dementia risk. In contrast, hypertension was associated with a decreased dementia risk. When the four significant conditions were analyzed simultaneously, estimates were similar and three of the four diseases remained significantly associated with dementia, suggesting these conditions relate to dementia independently of each other. Conclusions: Our results suggest that the association with dementia changes with age for some but not all cardiovascular risk factors, as some continue to have an increased risk while others have a decreased risk at very advanced ages. As many of these risk factors are potentially modifiable, understanding their unique contribution to dementia in the oldest-old is crucial. Study Supported by: Supported by PHS grant AG021055