Although there is general agreement that the diagnosis of dementia reduces life expectancy, the estimated number of years for survival following the onset of dementia has been reported to vary from 3 to over 9 years. We examined mortality in 3602 participants of the Cardiovascular Health Cognition Study in four U.S. communities evaluated for dementia incidence between 1992 and 1999 and followed an average of 6.5 years. Alzheimer’s disease (AD) was determined using NINCDS–ADRDA criteria and vascular dementia (VaD) used ADDTC criteria. Average age of the cohort was 75.1 years. By June 2000, 33 of 62 (53.2%) participants with VaD had died compared to 79 of 245
(32.2%) with AD, 66 of 151 (43.7%) with both AD and VaD, and 429 of 2318 (18.5%) with normal cognition. Using Cox proportional hazards regression with a time-dependent covariate for dementia status adjusted for age, gender and race, individuals with VaD were more than four times as likely to die during follow-up than those with normal cognitive status (HR: 4.4, 95% CI: 3.1–6.3). The hazard ratios were 2.1 (95% CI: 1.6–2.7) for AD and 2.5 (95% CI: 1.9–3.3) for both types. Individuals with VaD were more likely to die of cerebrovascular disease (42.4%) than those with AD (9.2%), both types (9.2%) or with normal cognition (7.5%). Accelerated life models estimated median survival from dementia onset to death as 3.8 years for those with VaD only, 6.8 years for those with AD only, and 5.2 years for those with both types of dementia.