Effects of dementia on mortality in the radiation effects research foundation adult health study

BACKGROUND: Although dementia is rarely listed on death certificates, it does contribute to mortality. The predominant immediate causes of death coincident with dementia are pneumonia and cardiovascular diseases. OBJECTIVE: To estimate the impact of dementia on specific mortality risks. METHODS: We applied DSM-III/R criteria for Alzheimer's disease (AD) and vascular dementia (VaD) to 2,172 subjects of the Adult Health Study of the Radiation Effects Research Foundation who were 60 or more years old when examined from 1992 to 1996. The underlying causes of death were compiled from death certificates. We performed a Poisson regression analysis to evaluate specific causes of mortality for which AD or VaD was a significant risk factor. RESULTS: The relative risk of mortality was 2.2 for AD and 2.4 for VaD. Mortality from pneumonia and stroke was elevated for both types of dementia, independent of other medical conditions. AD was also associated with death from trauma. CONCLUSION: Dementia was a predictor of death due to pneumonia, stroke, and trauma among the Japanese elderly. The prevention and early detection of those conditions are important in the medical care and treatment of dementia cases.