Projections of Alzheimer's disease in the United States and the public health impact of delaying disease onset.
OBJECTIVE
The goal of this study was to project the future prevalence and incidence of Alzheimer's disease in the United States and the potential impact of interventions to delay disease onset.


METHODS
The numbers of individuals in the United States with Alzheimer's disease and the numbers of newly diagnosed cases that can be expected over the next 50 years were estimated from a model that used age-specific incidence rates summarized from several epidemiological studies, US mortality rates, and US Bureau of the Census projections.


RESULTS
in 1997, the prevalence of Alzheimer's disease in the United States was 2.32 million (range: 1.09 to 4.58 million); of these individuals, 68% were female. It is projected that the prevalence will nearly quadruple in the next 50 years, by which time approximately 1 in 45 Americans will be afflicted with the disease. Currently, the annual number of new incident cases in 360,000. If interventions could delay onset of the disease by 2 years, after 50 years there would be nearly 2 million fewer cases than projected; if onset could be delayed by 1 year, there would be nearly 800,000 fewer prevalent cases.


CONCLUSIONS
As the US population ages, Alzheimer's disease will become an enormous public health problem. interventions that could delay disease onset even modestly would have a major public health impact.
Brookmeyer
R
R
Department of Biostatistics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 22105-2179, USA. rbrook@jhsph.edu
Gray
S
S
Kawas
C
C
D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000191:economics / Q000453:epidemiology*; D005260:Female; D005544:Forecasting; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011634:Public Health; D012044:Regression Analysis; D012737:Sex Factors; D014481:United States / Q000453:epidemiology