Dementia-free life expectancy in France

Increasing concern with the quality of gains in life years has led to the development of a new synthetic indicator of population health:health expectancy. Until now, calculations have been made for physical disabilities only. A first estimate of mental health expectancy is presented: dementia-free life expectancy.

Sullivan's method was used to calculate dementia-free life expectancy for a random representative sample of 4134 persons over 65 years of age in the Bordeaux region of France. The diagnosis of senile dementia was made in two stages, based on Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria.

At 65 years of age, a person's dementia-free life expectancy is 16.9 years within a total life-expectancy of 17.7 years; it decreases with age in parallel with the decrease in total life expectancy so that life expectancy with dementia stays constant at 0.8 years. Although dementia prevalence increases with age, if the prevalence is adjusted for mortality, the largest number of persons with dementia are in their early eighties. At each age women have a higher dementia-free life expectancy.

Trends in dementia-free life expectancy are similar to those found in disability-free life expectancy. Because the dementia prevalence rates used in this estimate resemble a general model derived from meta-analysis, it can be assumed that similar results will be found in other Western countries with similar mortality rates.