Dementia-free life expectancy in Australia.

Dementia-free life expectancy is a synthetic indicator of an important aspect of mental health which may have considerable use in public health decision making. Dementia expectancies were derived from senile dementia prevalence rates in Australia in 1991-1992 in conjunction with national life tables using Sullivan's method. Dementia-free life expectancy for Australian women aged 70 years was found to be 14 years within a total life expectancy of 15 years, and 11 years for men within a total life expectancy of 12 years. Between 70 and 85 years there is a constant average expectation of about one year of life expectancy with dementia. The age at which the largest number of persons with dementia is found is 82 years. Australians appear to have very similar dementia-free life expectancies to those reported in the European studies, with small differences probably due to sampling variation or to differences in case-finding methods.