Treatment for Alzheimer's may be necessary before 50
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The researchers found that in people genetically prone to Alzheimer's, significant amounts of a brain-clogging protein start moving from the spinal fluid to the brain about age 50 or younger.
"It can be going on for decades before we have an inkling of symptoms," said Dr. Elaine Peskind, associate director of the University of Washington Alzheimer's Disease Research Center at the VA Puget Sound Health Care System in Seattle.
Previous research has indicated that Alzheimer's begins years before symptoms appear. But this latest work by Peskind, the lead scientist, and her colleagues is the first to look at early signs across a wide range of ages -- from 21 to 88. The research is particularly significant because scientists predict a dramatic increase in Alzheimer's in the decades ahead. About 4.5 million people in the United States have the disease, and researchers say that could increase to 16 million by 2050.
Peskind and scientists from five other medical centers analyzed the effects of aging and the presence of a gene connected to Alzheimer's, APOE4, on 184 adult volunteers with an average age of 50 and all mentally normal.
People with the APOE4 gene have a higher Alzheimer's risk because it produces a sticky protein, called beta amyloid, in the form of a plaque that is thought to damage brain cells.
Among the volunteers with the gene, the level of one important form of the protein in the spinal fluid was dramatically lower in participants 50 and older than in the younger ones.
The decline in levels "possibly begins in young adulthood" in those with the gene, the scientists report in the July edition of the Archives of Neurology. Among the volunteers without the gene, the protein levels dropped slowly into old age.
About a quarter of the population has the APOE4 gene, though there are other physical factors that also influence whether a person develops the disease. Because there is no cure or vaccine for Alzheimer's, such tests would be unwise now, because they could affect whether someone could obtain health insurance or long-term-care insurance, she said.
The four prescription drugs now available for Alzheimer's merely ease the symptoms for a few years. Other drugs are under investigation, including two at the University of Washington. One is to remove the plaque. The other is to prevent its production.
But Peskind predicts it will be many years before a major drug will be available to prevent or control the disease. "I think within 10 years, it will definitely be possible," she said.
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