U.S. Alzheimer's Cases
To Triple, Study Shows

WASHINGTON (Reuters) - The number of Alzheimer's cases in the United States will more than triple over the next 50 years, although drugs that could in the future delay the onset of the brain-destroying disease would help significantly, researchers said Tuesday. Ron Brookmeyer and colleagues at the Johns Hopkins University School of Public Health examined several studies linking Alzheimer's to age and found that about 2.3 million Americans currently suffer from the disease. Other estimates have ranged to above four million. About 4 percent of 75-year-olds, 8.5 percent of 80-year-olds and 28.5 percent of 90-year-olds suffer from Alzheimer's, which is incurable and always fatal, Brookmeyer's team found. ``It is estimated that there are approximately 360,000 new cases of Alzheimer's disease each year,'' they wrote in the American Journal of Public Health. The researchers, who specialize in such statistics, compared those rates to projections for the U.S. population and found cases would more than triple. ``Within the next 50 years, the prevalence could be expected to rise by a factor of 3.7, to 8.64 million,'' they wrote. ``The annual number of new cases could be expected to rise more than three-fold, from 360,000 cases in 1997 to 1.14 million new cases in 2047.'' But they said treatment that delayed the onset of disease would greatly reduce that impact. Delaying onset by one year would result in 210,000 fewer cases 10 years later and 770,000 fewer cases 50 years later. There are no drugs on the market that really do that, but companies are working to develop them. Current drugs can help symptoms. Two drugs are approved in the United States for use against Alzheimer's. Aricept, made by Japan's Eisai Co. Ltd. and distributed by Pfizer, can help reduce memory loss but eventually stops working. Warner-Lambert's Tacrine (Cognex) can slow the progression of the disease but not by very much. A third drug, metrifonate, which is made by Bayer, is up for approval by the U.S. Food and Drug Administration (FDA). Ginkgo, a tree extract, may also help sharpen the memory in Alzheimer's patients. Another problem is diagnosing Alzheimer's. Most experts agree the only real way to diagnose Alzheimer's is with a brain biopsy -- which is done after death. ``There has been continuing debate about whether Alzheimer's disease incidence rates continue to rise at the oldest ages, or if they eventually plateau or even decline,'' Brookmeyer said in a statement. ``The data in this study suggested that the risk of Alzheimer's disease continues to rise at least through age 90 but there is little reliable data about risk beyond 90.'' Alzheimer's starts with simple memory loss and advances to confusion, severe memory loss and physical deterioration as more brain cells are destroyed. There is a genetic factor, but outside influences are also important. Doctors are trying to learn what those might be -- from what food people eat, to viral or bacterial infections.