MONDAY, March 17, 2008 (HealthDay News) -- More than one-fifth of Americans over age 70 have some memory impairment that isn't classified as dementia, a new study finds.
While an estimated 3.5 million Americans suffer from dementia, another 5.4 million over age 70 have some memory loss that affects their lifestyle but isn't severe enough to limit their ability to function normally, the study authors said.
"An estimated 22 percent of individuals over age 70 have some type of cognitive impairment that does not reach the threshold of dementia," said lead researcher Brenda Plassman, an associate research professor of psychiatry at Duke University School of Medicine.
Previous studies hadn't been able to estimate this 22 percent number, Plassman said, adding, "The number is actually about 60 percent higher than the number who had dementia among the people in our study."
The findings are published in the March 18 issue of the Annals of Internal Medicine.
For the study, Plassman's team collected data on 856 people 71 years of age and older who were part of the Health and Retirement Study. The participants completed a neuropsychological exam, and close family members were asked about their relatives' memory and ability to do daily activities. The participants were followed from July 2001 through March 2005.
The researchers found that 22 percent of the participants had some form of memory loss that didn't reach the threshold for dementia. Among these people, about 24 percent had chronic health problems such as diabetes or heart disease that may have been the cause of their cognitive impairment.
"The people with cognitive impairment without dementia were at higher risk of progressing to dementia within a year or so," Plassman said. "We estimated that people with cognitive impairment without dementia progressed to dementia at about the rate of 12 percent a year."
"However, during the same time period, about 20 percent reverted back to normal cognition," Plassman said. "That's important, because these numbers are rather startling, and we don't want to give the impression that there's not hope out there," she added.
Plassman said she thinks that some of the people who reverted back to normal just didn't do well on the initial tests. "But I don't think we really know the answer," she said. "We need more research to determine who will progress to dementia and who will not."
People with cognitive impairment without dementia may encounter problems with daily living, Plassman said. For example, they may not be able to communicate their health problems to their doctors or be able to follow doctor's directions.
And "they may be at risk for being taken advantage of," Plassman said.
Colin Milner, chief executive officer of the International Council on Active Aging, thinks the fast pace of modern life may contribute to memory problems among seniors.
"If you take your time, you will find that there are a lot of things you can do without losing your edge," he said. "We get so busy that some of the symptoms that are associated with memory loss are also associated with a fast-paced lifestyle," he said.
Milner thinks the key to aging well is finding balance in your life. "We don't take the time to really enjoy experiences, books or the newspaper," he said. "Slow down and take in what's around you. When you do that, you'd be surprised at how much clearer everything is."
Milner also believes that keeping your mind active can help stave off cognitive decline. For example, he recommends playing "brain games," such as crossword puzzles
"If you can find a cognitive challenge on a regular basis that is fun and you enjoy doing, you can keep your mind sharp," Milner said. "Your brain is like your body -- use it or lose it."
For more about memory, visit the U.S. National Library of Medicine.