Washington Alzheimer's disease is increasing so fast that more than 22 million people worldwide will be affected by 2025, experts warned Sunday. They urged new research to spot the very earliest symptoms and hunt for ways to protect these people's brains.
Already, doctors have discovered that a mild memory impairment sometimes confused with normal aging can progress to full-blown Alzheimer's at a rate of about 12 percent a year.
This "mild cognitive impairment" is "a slippery slope to Alzheimer's," Dr. Ronald Petersen of the Mayo Clinic told scientists gathered for the world's largest Alzheimer's meeting. The challenge now, he said, is "can we predict who will convert more rapidly?"
There is no known cure for Alzheimer's, which today afflicts about 4 million Americans and 8 million others. Scientists do not know what causes the sticky brain deposits that inevitably kill off neural cells until memory disintegrates and ultimately the patient dies.
Lots of risks are under study. Certain genes make some families vulnerable. Head injuries may increase risk; high blood pressure is a new suspect.
People with more education, in contrast, seem at lower risk of Alzheimer's. A study presented Sunday of twins where one twin had Alzheimer's and the other was healthy suggests a love of reading might be protective.
But the biggest risk for Alzheimer's is age: Alzheimer's cases double with every five years of age between 65 and 85.
With global population aging, "We have an imminent worldwide epidemic," warned Edward Truschke, president of the Alzheimer's Assn. "If we don't find a cure ... more than 22 million people will have this disease in 25 years."
Worse, by 2050, 45 million people worldwide may have Alzheimer's, a toll rivaling cancer, Dr. Robert Katzman of the University of California said.