Age-specific and sex-specific prevalence and incidence of mild cognitive impairment, dementia, and Alzheimer dementia in blacks and whites: a report from the Einstein Aging Study.

As the population ages, the need to characterize rates of cognitive impairment and dementia within demographic groups defined by age, sex, and race becomes increasingly important. There are limited data available on the prevalence and incidence of amnestic mild cognitive impairment (aMCI) and nonamnestic mild cognitive impairment (naMCI) from population-based studies. The Einstein Aging Study, a systematically recruited community-based cohort of 1944 adults aged 70 or older (1168 dementia free at baseline; mean age, 78.8 y; average follow-up, 3.9 y), provides the opportunity to examine the prevalence and incidence rates for dementia, Alzheimer dementia (AD), aMCI, and naMCI by demographic characteristics. Dementia prevalence was 6.5% (4.9% AD). Overall dementia incidence was 2.9/100 person-years (2.3/100 person-years for AD). Dementia and AD rates increased with age but did not differ by sex. Prevalence of aMCI was 11.6%, and naMCI prevalence was 9.9%. aMCI incidence was 3.8 and naMCI incidence was 3.9/100 person-years. Rates of aMCI increased significantly with age in men and in blacks; sex, education, and race were not significant risk factors. In contrast, naMCI incidence did not increase with age; however, blacks were at higher risk compared with whites, even when controlling for sex and education. Results highlight the public health significance of preclinical cognitive disease.