Objectives: This article provides estimates of the prevalence of cognitive impairment by age and sex for a nationally representative sample of the U.S. population aged 70 and over. From these estimates, years of life with and without cognitive impairment are calculated.
Methods: Using data from the Assets and Health Dynamics of the Oldest Old (AHEAD) survey, the prevalence of cognitive impairment is estimated for a sample representing both the community-dwelling and institutionalized older American population. Sullivan's method is used to calculate the average number of years an elderly person can expect to live with and without cognitive impairment.
Results: The prevalence of moderate to severe cognitive impairment in the total U.S. population aged 70 and over is 9.5%. At age 70, the average American can expect 1.5 years with cognitive impairment. Expected length of life with cognitive impairment is longer for women than men because of their longer life expectancy.
Discussion: As total life expectancy continues to increase, the length of life with cognitive impairment for the American population will increase unless age-specific prevalence is reduced. There is great potential for improvement in future early treatment and diagnosis of this condition.