Mayo Clinic Scientist Dr. Ron Peterson presented data at the International Alzheimer's Conference in Chicago that shows an astounding increase, particularly in men, in what was presented to the world media as Pre-Dementia.
Pre-Dementia, one form of which is sometimes called MCI, or Mild Cognitive Impairment, refers to decline in cognitive ability amongst younger adults that may become Alzheimer's.
Breathtakingly, up to 1 million people every year in the U.S. are new sufferers of pre-Dementia, not including the 500,000 people per annum who are diagnosed with Alzheimer's by a physician.
"We're seeing that in fact there's a much larger burgeoning problem out there" of people at risk of developing dementia, said Dr. Ronald Petersen, the Mayo scientist who led the study.
Dr. Ralph Nixon, a New York University psychiatrist and scientific adviser to the Alzheimer's Association, was blunt.
"We're facing a crisis," he said.
There are no treatments now to prevent this mental slide or reverse it once it starts.
But that may be changing. Researchers on Monday reported early, somewhat encouraging results from an experimental nose spray that seemed to improve certain memory measures in a study of mildly impaired people.
The drug, for now just called AL-108, needs testing in a longer, larger study. It is being developed by Allon Therapeutics Inc., based in Vancouver, B.C.
Doctors said it shows the potential for new types of medicines that target the protein tangles that kill nerve cells, instead of targeting the sticky brain deposits that have gotten most of the attention up to now.
The studies were reported at the International Conference on Alzheimer's Disease in Chicago.
Petersen is the scientist who defined mild cognitive impairment, or MCI, as a transition phase between healthy aging and dementia. It is more than "senior moments" like forgetting where you parked the car, but not as severe as having dementia, where you forget what a car is for.
People with it have impaired memory but not other problems like confusion, inattention or trouble putting thoughts into words.
The Alzheimer's Association says more than 5 million Americans have Alzheimer's, but no estimate for this "pre-dementia" has been available until now.
Petersen's federally funded study involved roughly 1,600 people, ages 70 through 89, living in Olmstead County, which surrounds the Mayo Clinic in Rochester, Minn. All tested normal when they were enrolled in the study, but more than 5 percent had developed mild impairment when evaluated a year later.
Men were nearly twice as likely as women to develop it. That's a surprise, because some studies have found more women with Alzheimer's than men. But there may be a simple explanation:
Even though more men may be impaired, women outlive them and therefore have more time to develop full-blown dementia.
"This is a very large and important issue for our country and for the world," said Duke University psychologist Brenda Plassman. A smaller study she published earlier this year backs up the Mayo study's findings.
The mild impairment rate is two to three times larger than many researchers had expected, Petersen said.
"It's the iceberg under the tip," agreed Dr. R. Scott Turner, incoming director of the memory disorders program at Georgetown University Medical Center. A prime goal is finding drugs to treat the mild impairment before Alzheimer's develops.