More people than expected will develop an early form of Alzheimer's, according to researchers at the Mayo Clinic.
Mild Cognitive Impairment is an intermediate stage between Alzheimer's and normal aging.
In an observational study researchers found five percent of people between the ages of 70 to 89 develop the disease. Researchers expected that number to be one to two percent.
Mayo Clinic neurologist Ron Petersen said more than 24 million Americans are in that age range.
"This would translate into a rate of over a million people a year progressing into mild cognitive impairment and that really translates into a staggering figure," Petersen said.
Petersen said currently there are no drug treatments for the disease. He said that's particularly concerning as the Baby Boomer generation continues to age.