February 12, 2007
An updated review of the most common nervous system disorders in the United States found that 67 out of every 1,000 elderly Americans carries a diagnosis of Alzheimer's disease, a figure substantially higher than previous estimates. The findings were published in the January 30 issue of , the scientific journal of the American Academy of Neurology.
"Current, accurate estimates of the numbers of people affected by neurological disorders are needed to understand the burden of these conditions on patients, families, and society, to plan and carry out research on their causes and treatment, and to provide adequate services to people who suffer from these illnesses," said study leader Deborah Hirtz, MD, of the National Institute of Neurological Disorders and Stroke at the National Institutes of Health.
An estimated 4.5 million Americans currently suffer from Alzheimer's. With an aging population, that number is expected to grow considerably in coming decades unless a cure or effective treatment is found. Existing medications for Alzheimer's may provide temporary relief of symptoms but do nothing to stop the relentless downward progression of disease.
The current figures come from an in-depth analysis of nearly 500 scientific articles published between 1990 and 2005 in the United States and Europe. The Alzheimer's prevalence rate, of 1,275 people per 100,000 seniors age 65 and up, is higher than that for other common neurologic ailments in the elderly, including stroke (1,093 per 100,000) and Parkinson's disease (160 per 100,000). It is also far higher than the general population rate for multiple sclerosis (4.2 per 100,000), epilepsy (48 per 100,000), traumatic brain injuries (101 per 100,000), or ALS (Lou Gehrig's disease, 1.6 per 100,000).
"Neurologic disease affects millions of people worldwide, with the burden of such disease likely to grow as populations grow older," says Dr. Steven M. Albert of the University of Pittsburgh in an editorial accompanying the study. "Current projections of Alzheimer's disease suggest that there will be about 10 million cases in the United States in 2050, of which 6 million are expected to have moderate or severe dementia." Others put those estimates as high as 16 million Alzheimer's cases by 2050, with up to 9 million being moderate to severe.
Dr. Albert describes the effects that new Alzheimer's therapies might have on overall Alzheimer's prevalence. With a pill or other therapy that slowed Alzheimer's progression, he estimates the total number of cases would still be about 10 million in the year 2050, though more people (about 6 million) would have mild disease. With a treatment that delayed the onset of Alzheimer's by 6 to 7 years, the total number of cases would drop to 6 million in 2050, including 4 million with moderate to severe dementia. Even with a treatment that both delayed onset and slowed progression, there would still be about 6 million cases, including 2.5 million with moderate to severe Alzheimer's.
The figures call attention to the desperate need for a therapy that effectively treats, or even cures, Alzheimer's. The Fisher Center for Alzheimer's Research Foundation funds critical research into the search for an Alzheimer's cure. To learn more or to make a donation, visit www.ALZinfo.org.
D. Hirtz, MD; D.J. Thurman, MD, MPH; K. Gwinn-Hardy, MD, et al: "How Common Are the "Common" Neurologic Disorders?" (review article). Neurology, January 30, 2007, Volume 68, pages 326-337.
Steven M. Albert, PhD, MSPH: "Projecting Neurologic Disease Burden: Difficult but Critical" (editorial). Neurology, January 30, 2007, Volume 68, pages 322-323.